Reference voltage output circuit

Abstract

In a reference voltage output circuit (10), a first transistor (40) generates a first voltage (VA) caused by a first PN junction between a collector terminal (41) and an emitter terminal (42) by flowing a branch current (Ic) between the collector terminal (41) and the emitter terminal (42), and a second transistor (60) generates a second voltage (VA) caused by a second PN junction between the emitter terminal (61) and the collector terminal (62) by flowing a branch current between the emitter terminal (61) and the collector terminal (62). The resistance voltage divider circuit (50) adds a voltage obtained by multiplying the third voltage (VZ-VA) by the first weight and a voltage obtained by multiplying the second voltage (VB) by the second weight, and outputs the added voltage as a reference voltage (Vref). The temperature dependence of the Zener voltage (VZ) is offset by the temperature dependence of the first voltage and the temperature dependence of the second voltage, and the stress dependence of the Zener voltage is offset by the stress dependence of the first voltage and the stress dependence of the second voltage.

Description

Reference voltage output circuit Technical Field

[0001] This disclosure relates to a reference voltage output circuit. Background Technology

[0002] Previously, a reference voltage output circuit was proposed that is configured between a current source and ground to output a reference voltage (see, for example, Patent Document 1). The reference voltage output circuit includes a Zener diode and a voltage divider circuit. The Zener diode and the voltage divider circuit are connected in parallel between the current source and ground. The Zener diode has a cathode terminal connected to the current source and an anode terminal connected to ground. By allowing a portion of the main current flowing from the current source, i.e., a first branch current, to flow through the Zener diode, a Zener voltage is generated between the current source and ground using the Zener effect. The Zener voltage exhibits a positive temperature dependence, increasing with the temperature of the Zener diode.

[0003] The voltage divider circuit includes a first resistive element, a second resistive element, a first diode, and a second diode connected in series between the current source and ground. Hereinafter, the first diode and the second diode will be collectively referred to as the first and second diodes, and the first resistive element and the second resistive element will be collectively referred to as the first and second resistive elements. The first and second diodes are connected in series between the first and second resistive elements and ground. The anode terminal of the first diode is connected to the side of the first and second resistive elements, and the cathode terminal is connected to the second diode. The anode terminal of the second diode is connected to the first diode, and the cathode terminal is connected to ground. The first and second diodes each have a P-type semiconductor and an N-type semiconductor disposed on the ground side relative to the P-type semiconductor and bonded to the P-type semiconductor to form a PN junction. The remaining current in the main current, excluding the first branch current, i.e., the second branch current, flows to ground through the first and second resistive elements, the first and second diodes, and the second diode.

[0004] The voltage between the anode and cathode terminals of the first diode is caused by the PN junction, exhibiting a negative temperature dependence where the voltage decreases as the diode's temperature rises. Similarly, the voltage between the anode and cathode terminals of the second diode is caused by the PN junction, also exhibiting a negative temperature dependence where the voltage decreases as the diode's temperature rises. The voltage divider circuit adds the Zener voltage multiplied by a first weight, the first terminal voltage multiplied by a second weight, and the second terminal voltage multiplied by a third weight, and outputs this sum as the reference voltage. The first, second, and third weights are set by the voltage division of the first and second resistive elements, respectively. Thus, the temperature dependence of the Zener voltage is canceled out by the temperature dependence of the first and second terminal voltages. Therefore, changes in the reference voltage output from the voltage divider circuit due to temperature variations in the Zener diode can be suppressed.

[0005] Prior art literature, patent literature, patent literature 1: US Patent No. 3,916,508 specification Summary of the Invention

[0006] In the aforementioned reference voltage output circuit, the temperature dependence of the Zener voltage is offset by the temperature dependence of the voltage between the first and second terminals. Therefore, changes in the reference voltage caused by temperature variations in the Zener diode can be suppressed. However, when the Zener diode, the first diode, and the second diode constitute an integrated circuit device, the following undesirable situation may occur: the integrated circuit device is configured such that the Zener diode, the first diode, and the second diode are covered by a package component. For example, due to thermal expansion of the package component, stress may sometimes be applied to the Zener diode, the first diode, and the second diode from the package component.

[0007] The Zener voltage exhibits the following stress-dependent behavior: when tensile stress is applied to the Zener diode from the package component, the Zener voltage increases; when compressive stress is applied, the Zener voltage decreases. Similarly, the first terminal voltage exhibits the following stress-dependent behavior: when tensile stress is applied to the first diode from the package component, the first terminal voltage increases; when compressive stress is applied, the first terminal voltage decreases. The second terminal voltage exhibits the following stress-dependent behavior: when tensile stress is applied to the second diode from the package component, the second terminal voltage increases; when compressive stress is applied, the second terminal voltage decreases. Therefore, the reference voltage output from the voltage divider circuit changes according to the stress applied to the Zener diode from the package component.

[0008] In view of the above points, the present disclosure aims to provide a reference voltage output circuit that suppresses changes in the reference voltage caused by temperature changes and changes in the reference voltage caused by stress changes.

[0009] According to one aspect of this disclosure, a reference voltage output circuit includes: a current source disposed between the positive and negative electrodes of a DC power supply, wherein a main current, which is a constant DC current, flows from the positive electrode to the negative electrode based on the power supply voltage between the positive and negative electrodes; a Zener diode disposed between the current source and the negative electrode, wherein a first branch current, which is a portion of the main current, flows through it, thereby generating a Zener voltage caused by the Zener effect between the current source and the negative electrode; and a first semiconductor unit having: a first input terminal disposed between the current source and the negative electrode; a first output terminal disposed between the first input terminal and the negative electrode; and a first P-type diode disposed between the first input terminal and the first output terminal. The first semiconductor section includes: a first P-type semiconductor and a first output terminal; and a first N-type semiconductor disposed between the first P-type semiconductor and the first output terminal, and in contact with the first P-type semiconductor to form a first PN junction, wherein a second branch current in the main current, other than the first branch current, flows from the first input terminal through the first PN junction to the first output terminal, thereby generating a first voltage caused by the first PN junction between the first input terminal and the first output terminal; a second semiconductor section having: a second input terminal disposed between the first semiconductor section and the negative electrode; a second output terminal disposed between the second input terminal and the negative electrode; a second P-type semiconductor disposed between the second input terminal and the second output terminal; and a second N-type semiconductor disposed between the second P-type semiconductor and the second output terminal. The second N-type semiconductor, which forms a second PN junction in contact with the second P-type semiconductor, has a second branch current flowing from the second input terminal through the second PN junction to the second output terminal, thereby generating a second voltage caused by the second PN junction between the second input terminal and the second output terminal; and a reference voltage generation unit, disposed between the first semiconductor unit and the second semiconductor unit, outputs a reference voltage. The Zener diode, the first semiconductor unit, and the second semiconductor unit are configured to be covered by a packaged component. The Zener voltage has a temperature dependence that varies with the temperature of the Zener diode, and the first voltage has a temperature dependence that varies with the temperature of the first semiconductor unit, and the first voltage varies with the temperature of the first semiconductor unit applied from the packaged component to the first... The second voltage has a stress dependence that varies with the temperature of the second semiconductor part and a stress dependence that varies with the stress applied to the second semiconductor part from the packaging component. When the voltage obtained by reducing the Zener voltage by the amount of the first voltage is set as the third voltage, the reference voltage generation unit outputs a voltage obtained by adding the voltage obtained by multiplying the third voltage by the first weight and the voltage obtained by multiplying the second voltage by the second weight as the reference voltage. The temperature dependence of the Zener voltage is offset by the temperature dependence of the first voltage and the temperature dependence of the second voltage, and the stress dependence of the first voltage and the stress dependence of the second voltage are offset.

[0010] Therefore, it is possible to provide a reference voltage output circuit that suppresses changes in the reference voltage caused by temperature variations and changes in the reference voltage caused by stress variations.

[0011] According to another aspect of this disclosure, a reference voltage output circuit includes: a current source disposed between the positive and negative electrodes of a DC power supply, wherein a main current, which is a constant DC current, flows from the positive electrode to the negative electrode based on the power supply voltage between the positive and negative electrodes; a Zener diode disposed between the current source and the negative electrode, wherein a first branch current, which is a portion of the main current, flows through it, thereby generating a Zener voltage caused by the Zener effect between the current source and the negative electrode; and a first semiconductor section having: a first input terminal disposed between the current source and the negative electrode; a first output terminal disposed between the first input terminal and the negative electrode; a first P-type semiconductor disposed between the first input terminal and the first output terminal; and a first PN junction disposed between the first P-type semiconductor and the first output terminal, and in contact with the first P-type semiconductor. The first N-type semiconductor has a second branch current (other than the first branch current) flowing from the first input terminal through the first PN junction to the first output terminal, thereby generating a first voltage caused by the first PN junction between the first input terminal and the first output terminal; the second semiconductor section has: a second input terminal disposed between the first semiconductor section and the negative electrode; a second output terminal disposed between the second input terminal and the negative electrode; a second P-type semiconductor disposed between the second input terminal and the second output terminal; and a second N-type semiconductor disposed between the second P-type semiconductor and the second output terminal, and in contact with the second P-type semiconductor to form a second PN junction, wherein a second branch current flows from the second input terminal through the second PN junction to the second output terminal, thereby generating a second voltage caused by the second PN junction between the second input terminal and the second output terminal;A reference voltage generation unit is disposed between the first semiconductor unit and the second semiconductor unit to output a reference voltage. The Zener diode, the first semiconductor unit, and the second semiconductor unit are configured to be covered by a packaged component. The Zener voltage has a temperature dependence that varies with the temperature of the Zener diode and a stress dependence that varies with the stress applied to the Zener diode from the packaged component. The first voltage has a temperature dependence that varies with the temperature of the first semiconductor unit and a stress dependence that varies with the stress applied to the first semiconductor unit from the packaged component. The second voltage has a temperature dependence that varies with the temperature of the second semiconductor unit. The reference voltage generator outputs a voltage obtained by multiplying the third voltage by a first weight and the second voltage by a second weight, using the temperature dependence of the first voltage and the stress dependence of the second voltage as a function of the temperature dependence of the first voltage and the stress dependence of the second voltage, respectively. This voltage is used to offset the temperature dependence of the Zener voltage using the temperature dependence of the first voltage and the temperature dependence of the second voltage, and also to offset the stress dependence of the first voltage and the stress dependence of the second voltage.

[0012] Therefore, it is possible to provide a reference voltage output circuit that suppresses changes in the reference voltage caused by temperature variations and changes in the reference voltage caused by stress variations. Attached Figure Description

[0013] Figure 1 is a circuit diagram showing the overall structure of the reference voltage output circuit in the first embodiment of this disclosure, and is a diagram showing the connection relationship of the current source, Zener diode, two transistors, and resistor voltage divider circuit.

[0014] Figure 2 is a cross-sectional view of an integrated circuit device in which an IC chip constituting the reference voltage output circuit of the first embodiment of Figure 1 is built. It is a diagram used to illustrate the temperature dependence and stress dependence of the Zener voltage, the first voltage, and the second voltage.

[0015] Figure 3 is a circuit diagram showing the overall structure of the reference voltage output circuit in the comparative example of the first embodiment. It shows the connection relationship of the current source, Zener diode, two diodes, and resistor voltage divider circuit.

[0016] Figure 4 is a circuit diagram showing the overall structure of the reference voltage output circuit in the second embodiment of this disclosure, and it shows the connection relationship of the current source, Zener diode, two transistors, and resistor voltage divider circuit.

[0017] Figure 5 is a circuit diagram showing the detailed circuit structure of the resistor divider circuit of the reference voltage output circuit in the second embodiment of Figure 4. It is a diagram showing the connection relationship of multiple resistive elements and multiple switches.

[0018] Figure 6 is a circuit diagram showing the overall structure of the reference voltage output circuit in the third embodiment of this disclosure, and is a diagram showing the connection relationship of the current source, Zener diode, diode, transistor, and resistor voltage divider circuit.

[0019] Figure 7 is a circuit diagram showing the overall structure of the reference voltage output circuit in the fourth embodiment of this disclosure. It is a diagram showing the connection relationship of the current source, Zener diode, two diodes, transistor, and resistor voltage divider circuit.

[0020] Figure 8 is a circuit diagram showing the overall structure of the reference voltage output circuit in the fifth embodiment of this disclosure, and is a diagram showing the connection relationship of the current source, two diodes, two Zener diodes, and the resistor voltage divider circuit.

[0021] Figure 9 is a circuit diagram showing the overall structure of the reference voltage output circuit in the sixth embodiment of this disclosure, and is a diagram showing the connection relationship of the current source, two Zener diodes, two diodes, and the resistor voltage divider circuit.

[0022] Figure 10 is a circuit diagram showing the overall structure of the reference voltage output circuit in the seventh embodiment of this disclosure, and is a diagram showing the connection relationship of the current source, two Zener diodes, two diodes, and the resistor voltage divider circuit.

[0023] Figure 11 is a circuit diagram showing the overall structure of the reference voltage output circuit in the eighth embodiment of this disclosure, and is a diagram showing the connection relationship of the current source, a Zener diode, two transistors, and the resistor voltage divider circuit. Detailed Implementation

[0024] Hereinafter, embodiments of the present disclosure will be described based on the accompanying drawings. Furthermore, in order to simplify the description of each of the following embodiments, identical or equivalent parts will be labeled with the same symbols in the drawings.

[0025] (First Embodiment) As shown in FIG1, the reference voltage output circuit 10 includes a current source 20, a Zener diode 30, a transistor 40, a resistor voltage divider circuit 50, and a transistor 60. The current source 20 is disposed between the positive electrode 1 and the negative electrode 2 of the DC power supply. The current source 20 is a constant current power supply with a main current Ia flowing from the positive electrode 1 to the negative electrode 2 as a constant DC current based on the power supply voltage (i.e., DC voltage) between the positive electrode 1 and the negative electrode 2.

[0026] In this embodiment, Zener diode 30 is disposed between current source 20 and negative electrode 2. Transistors 40 and 60 and resistor divider circuit 50 are disposed between current source 20 and negative electrode 2. Therefore, transistors 40 and 60 and resistor divider circuit 50 are connected in parallel with Zener diode 30 between current source 20 and negative electrode 2. A branch current Ib, which is the first branch current, flows through Zener diode 30. Branch current Ib is a portion of the main current Ia. A branch current Ic, which is the second branch current, flows through transistors 40 and 60 and resistor divider circuit 50. Branch current Ic is the remaining current in the main current Ia other than branch current Ib.

[0027] The Zener diode 30 has a cathode terminal 31 connected to the current source 20 and an anode terminal 32 connected to the negative electrode 2. The Zener diode 30 generates a Zener voltage between the cathode terminal 31 and the anode terminal 32 due to the Zener effect by the flow of a branch current Ib from the current source 20. That is, the Zener diode 30 generates a Zener voltage between the current source 20 and the negative electrode 2 due to the Zener effect.

[0028] Transistor 40 has a collector terminal 41 connected to the current source 20 as a first input terminal and an emitter terminal 42 connected to the resistor divider circuit 50 as a first output terminal. Transistor 40 is a first semiconductor portion having a base terminal 43 connected to the collector terminal 41. Thus, transistor 40 is connected to a diode. In this embodiment, a bipolar junction transistor (BJT) is used as transistor 40. BJT is an abbreviation for bipolar junction transistor. Furthermore, bipolar junction transistor will also be referred to as BJT below. An NPN type transistor is used as transistor 40. Transistor 40 includes an N-type semiconductor disposed between the current source 20 and the resistor divider circuit 50, a P-type semiconductor disposed between the N-type semiconductor and the resistor divider circuit 50, and an N-type semiconductor disposed between the P-type semiconductor and the resistor divider circuit 50.

[0029] Furthermore, for ease of explanation and to distinguish the two N-type semiconductors constituting transistor 40, the following description is provided: The N-type semiconductor disposed between the current source 20 and the P-type semiconductor is designated as the positive-side N-type semiconductor, and the N-type semiconductor disposed between the P-type semiconductor and the resistor divider circuit 50 is designated as the negative-side N-type semiconductor. The positive-side N-type semiconductor is connected to the collector terminal 41. The P-type semiconductor is connected to the base terminal 43. The P-type semiconductor is the first P-type semiconductor that forms a first PN junction with the negative-side N-type semiconductor. The negative-side N-type semiconductor is the first N-type semiconductor connected to the emitter terminal 42. Hereinafter, transistor 40 and transistor 60 will also be collectively referred to as transistors 40 and 60.

[0030] The resistor divider circuit 50 in Figure 1 is a reference voltage generation unit disposed between transistors 40 and 60. The resistor divider circuit 50 includes resistor element 50a and resistor element 50b. Resistor element 50a and resistor element 50b are also collectively referred to as resistor elements 50a and 50b. Resistor elements 50a and 50b are connected in series between transistors 40 and 60. Furthermore, resistor element 50a is disposed on the transistor 40 side relative to resistor element 50b. Resistor elements 50a and 50b form a common connection terminal 51 that is mutually connected. In this embodiment, the common connection terminal 51 is connected to an output unit 52. As described later, the output unit 52 outputs a reference voltage Vref.

[0031] Transistor 60 is disposed between resistor divider circuit 50 and negative electrode 2. Transistor 60 has an emitter terminal 61 connected to resistor divider circuit 50 as a second input terminal, and a collector terminal 62 connected to negative electrode 2 as a second output terminal. Transistor 60 is a second semiconductor portion having a base terminal 63 connected to collector terminal 62. Thus, transistor 60 is connected as a diode. In this embodiment, BJT is used as transistor 60, similar to transistor 40.

[0032] A PNP type transistor is used as transistor 60. Transistor 60 includes a P-type semiconductor disposed between the resistor divider circuit 50 and the negative electrode 2, an N-type semiconductor disposed between the P-type semiconductor and the negative electrode 2, and a P-type semiconductor disposed between the N-type semiconductor and the negative electrode 2. Hereinafter, for ease of explanation and to distinguish the two P-type semiconductors constituting transistor 60, the following description will be provided: The P-type semiconductor disposed between the resistor divider circuit 50 and the N-type semiconductor is designated as the positive-side P-type semiconductor, and the P-type semiconductor disposed between the N-type semiconductor and the negative electrode 2 is designated as the negative-side P-type semiconductor. The positive-side P-type semiconductor is connected to the emitter terminal 61. The positive-side P-type semiconductor is a second P-type semiconductor that forms a second PN junction with the N-type semiconductor. The N-type semiconductor is a second N-type semiconductor connected to the base terminal 63. The negative-side P-type semiconductor is connected to the collector terminal 62.

[0033] In this embodiment, the current source 20, Zener diode 30, transistors 40 and 60, and resistor voltage divider circuit 50 constitute the IC chip 71 shown in FIG2. That is, the IC chip 71 includes the current source 20, Zener diode 30, transistors 40 and 60, and resistor voltage divider circuit 50. FIG2 is a cross-sectional view of an integrated circuit device 70 including the IC chip 71 of this embodiment. The IC chip 71, together with the substrate 72, adhesive layer 73, multiple lead frames 74, multiple bonding wires 75, and resin component 76, constitute the integrated circuit device 70. The IC chip 71 is disposed on one side of the substrate 72 in the thickness direction Ya.

[0034] The IC chip 71 is fixed to one side of the substrate 72 in the thickness direction Ya by an adhesive layer 73. Multiple lead frames 74 electrically connect the circuit board on the outside of the integrated circuit device 70 to the IC chip 71. Multiple bonding wires 75 electrically connect one end 74a of each of the multiple lead frames 74 to the IC chip 71. The multiple bonding wires 75 are connected to the multiple lead frames 74 via pads 77. One end 74a of each of the multiple lead frames 74 is disposed inside the resin component 76.

[0035] The other end 74b of each of the plurality of lead frames 74 is disposed on the outside of the resin component 76. The IC chip 71, the substrate 72, the adhesive layer 73, the plurality of lead frames 74, and the plurality of bonding wires 75 are covered by the resin component 76 from one side and the other side in the thickness direction Ya. The resin component 76 is a component made of a resin material having electrical insulating properties. The integrated circuit device 70 of this embodiment is used, for example, as an automotive electronic component. The resin component 76 together with the substrate 72 constitutes a package component formed in a manner that covers the IC chip 71. Next, the operation of the reference voltage output circuit 10 of this embodiment will be described with reference to FIGS. 1, 2, and 3.

[0036] First, current source 20, based on the power supply voltage between positive electrode 1 and negative electrode 2, causes the main current Ia to flow from positive electrode 1 to negative electrode 2. A branch current Ib of the main current Ia flows from current source 20 to negative electrode 2 through Zener diode 30. Accompanyingly, Zener diode 30 generates a Zener voltage VZ between current source 20 and negative electrode 2 due to the Zener effect. On the other hand, branch current Ic, excluding branch current Ib of the main current Ia, flows from current source 20 to negative electrode 2 through transistors 40 and 60 and resistors 50a and 50b.

[0037] A portion of the branch current Ic flows as the base current from the base terminal 43 of transistor 40 through the first PN junction to the emitter terminal 42. Therefore, transistor 40 is turned on. Simultaneously, the remaining current in transistor 40, excluding the base current, flows from the collector terminal 41 through the first PN junction to the emitter terminal 42. Therefore, the branch current Ic flows from the collector terminal 41 through the first PN junction to the emitter terminal 42. Consequently, a voltage VA caused by the first PN junction is generated between the collector terminal (i.e., the first input terminal) 41 and the emitter terminal 42 (i.e., the second output terminal).

[0038] Additionally, the branch current Ic flows from the emitter terminal 61 of transistor 60 through the second PN junction into the N-type semiconductor. The base current in this flowing branch current Ic flows from the N-type semiconductor to the base terminal 63. This outflowing base current bypasses the negative-side P-type semiconductor and flows to the collector terminal 62. Thus, transistor 60 is turned on. Therefore, the remaining current in the branch current Ic, excluding the base current, flows from the N-type semiconductor through the negative-side P-type semiconductor and the collector terminal 62 to the negative electrode 2.

[0039] Therefore, the branch current Ic flows from the emitter terminal 61 through the second P-type semiconductor and the collector terminal 62 to the negative electrode 2. Thus, a second voltage, VB, caused by the second PN junction is generated between the emitter terminal 61 and the collector terminal 62. Furthermore, the resistor divider circuit 50, as shown in equation 1, outputs a reference voltage Vref from the common connection terminal 51. This reference voltage is obtained by multiplying the voltage VZ-VA (obtained by stepping down the Zener voltage VZ by an amount equivalent to voltage VA) by a first weight, and the voltage VB by a second weight.

[0040] [Formula 1] Let the resistance value of resistor 50a be R1, and the resistance value of resistor 50b be R2. In Equation 1, the first weight is the value obtained by dividing R2 by R1+R2 (the sum of R1 and R2). The second weight is the value obtained by dividing R1 by R1+R2. Therefore, the reference voltage Vref is the voltage obtained by superimposing the voltage divided by resistors 50a and 50b on the voltage VZ-VA.

[0041] For example, when the integrated circuit device 70 is mounted in an automobile, the ambient temperature of the integrated circuit device 70 rises, and sometimes heat is transferred from the periphery of the integrated circuit device 70 to the IC chip 71 through the resin component 76. In this case, the temperatures of both the resin component 76 and the IC chip 71 rise. The Zener voltage VZ has a temperature dependence. This temperature dependence is a positive temperature dependence, where the Zener voltage VZ increases as the temperature of the Zener diode 30 increases, and decreases as the temperature of the Zener diode 30 decreases. The voltage VA has a temperature dependence. This temperature dependence is a negative temperature dependence, where the voltage VA decreases as the temperature of the transistor 40 increases, and increases as the temperature of the transistor 40 decreases.

[0042] Therefore, the voltage VZ-VA exhibits a positive temperature dependence. Thus, as the temperatures of Zener diode 30 and transistor 60 increase, the voltage VZ-VA increases. Conversely, as the temperatures of Zener diode 30 and transistor 60 decrease, the voltage VZ-VA decreases. Additionally, the voltage VB exhibits a negative temperature dependence. This dependence is a condition where the voltage VB decreases as the temperature of transistor 60 increases, and increases as the temperature of transistor 60 decreases.

[0043] For example, in the packaging process of the integrated circuit device 70, when the IC chip 71 is fixed to the base 72 by an adhesive, the adhesive cures and shrinks, thereby applying stress to the IC chip 71 from the adhesive. For example, after the chip soldering process, when a resin component 76 is formed by covering the IC chip 71 with resin material, the resin material cures and shrinks, thereby applying stress to the IC chip 71 from the resin component 76.

[0044] Furthermore, the resin material expands or contracts due to heat and humidity, thereby applying stress to the IC chip 71 from the resin component 76. For example, when the packaged integrated circuit device 70 is soldered onto a circuit board, the molten solder solidifies and shrinks, thereby generating stress in the solder. This stress is applied to the IC chip 71 through the multiple lead frames 74 and the resin component 76. Stress caused by such temperature changes, humidity, soldering, etc., is applied to the IC chip 71 from the resin component 76, i.e., the packaging component.

[0045] Therefore, in this embodiment, stress is applied from the resin component 76 to the Zener diode 30, transistors 40 and 60. The Zener voltage VZ exhibits a stress dependence due to the piezoelectric bonding effect. This stress dependence is a positive stress dependence where the Zener voltage VZ increases when tensile stress is applied to the Zener diode 30 and decreases when compressive stress is applied to the Zener diode 30.

[0046] The voltage VA exhibits a stress dependence caused by the piezoelectric bonding effect. This stress dependence is a positive stress dependence, where the voltage VA increases when tensile stress is applied to transistor 40, and decreases when compressive stress is applied to transistor 40. The voltage VB also exhibits a positive stress dependence caused by the piezoelectric bonding effect. This stress dependence is a positive stress dependence, where the voltage VB increases when tensile stress is applied to transistor 60, and decreases when compressive stress is applied to transistor 60.

[0047] Here, the stress applied to the Zener diode 30, transistors 40 and 60 by the resin component 76 is defined as σ. Furthermore, the value obtained by partially differentiating the stress with respect to the reference voltage Vref is defined as the stress coefficient of the reference voltage Vref. The value obtained by partially differentiating the stress with respect to the Zener voltage VZ is defined as the stress coefficient of the Zener voltage VZ. The stress coefficient of the Zener voltage VZ is... Divide by The values ​​obtained are as follows: The value obtained by partial differentiation of voltage VA with respect to stress is set as the stress coefficient of voltage VA. The value obtained by partial differentiation of voltage VB with respect to stress is set as the stress coefficient of voltage VB.

[0048] The stress coefficient of the reference voltage Vref is shown in Equation 2, and can be expressed by the stress coefficients of the Zener voltage VZ, the voltage VA, and the voltage VB.

[0049] [Formula 2] In this embodiment, transistors 40 and 60 and Zener diode 30 are configured such that the stress coefficient of voltage VA is greater than that of voltage VB, and the stress coefficient of voltage VA is greater than that of Zener voltage VZ. Here, tensile stress is represented by positive values, and compressive stress by negative values. The value obtained by subtracting the stress coefficient of voltage VA from the stress coefficient of Zener voltage VZ is negative. The stress coefficient of voltage VB is positive. Therefore, as shown in Equation 2, the stress coefficient of the reference voltage Vref can be made close to zero.

[0050] In this embodiment, as described above, the resistor divider circuit 50 adds the voltage obtained by multiplying voltage VZ-VA by a first weight and the voltage obtained by multiplying voltage VB by a second weight, and uses the resulting voltage as the reference voltage Vref. Thus, the temperature dependence of the Zener voltage VZ is canceled out by the temperature dependence of voltage VA and voltage VB. Furthermore, the stress dependence of voltage VA and voltage VB cancel each other out. Therefore, the stress dependence of the Zener voltage VZ is canceled out by the stress dependence of voltage VA.

[0051] According to the embodiment described above, the reference voltage output circuit 10 includes a current source 20, a Zener diode 30, transistors 40 and 60, and a resistor divider circuit 50. The current source 20 is disposed between the positive electrode 1 and the negative electrode 2 of the DC power supply, and a main current Ia flows from the positive electrode 1 to the negative electrode 2 based on the power supply voltage between the positive electrode 1 and the negative electrode 2. The Zener diode 30 is disposed between the current source 20 and the negative electrode 2, and has a cathode terminal 31 connected to the current source 20 and an anode terminal 32 connected to the negative electrode 2.

[0052] The Zener diode 30 generates a Zener voltage between the current source 20 and the negative electrode 2 by allowing a portion of the main current Ia to flow through the cathode terminal 31 and the anode terminal 32, thereby generating a Zener voltage caused by the Zener effect. Additionally, the transistor 40 includes a collector terminal 41 connected to the current source 20 and an emitter terminal 42 connected to the negative electrode 2. The transistor 40 has a first P-type semiconductor disposed between the collector terminal 41 and the emitter terminal 42, and a first N-type semiconductor disposed between the first P-type semiconductor and the emitter terminal 42 and in contact with the first P-type semiconductor to form a first PN junction.

[0053] The branch current Ic of the main current Ia, excluding a portion of the branch current Ib, flows through the first PN junction of transistor 40 between collector terminal 41 and emitter terminal 42. This generates a voltage VA between collector terminal 41 and emitter terminal 42 caused by the first PN junction. Transistor 60 is positioned between resistor divider circuit 50 and negative electrode 2. Transistor 60 has emitter terminal 61 connected to resistor divider circuit 50 and collector terminal 62 connected to negative electrode 2.

[0054] Transistor 60 has a second P-type semiconductor disposed between emitter terminal 61 and collector terminal 62, and a second N-type semiconductor disposed between the second P-type semiconductor and collector terminal 62 and in contact with the second P-type semiconductor to form a second PN junction. A branch current Ic flows between emitter terminal 61 and collector terminal 62 through the second PN junction of transistor 60. This generates a voltage VB between emitter terminal 61 and collector terminal 62 caused by the second PN junction. A resistor divider circuit 50 is disposed between transistors 40 and 60, outputting a reference voltage Vref from output section 52. Zener diode 30, transistors 40 and 60 are covered by resin component 76.

[0055] The Zener voltage VZ exhibits a temperature dependence that increases with increasing temperature of the Zener diode 30. The Zener voltage VZ also exhibits a stress dependence that increases when tensile stress is applied to the Zener diode 30 from the resin component 76 and decreases when compressive stress is applied. The voltage VA exhibits a temperature dependence that decreases with increasing temperature of the transistor 40. The voltage VA also exhibits a stress dependence that increases when tensile stress is applied to the transistor 40 from the resin component 76 and decreases when compressive stress is applied. The voltage VB exhibits a temperature dependence that decreases with increasing temperature of the transistor 60. The voltage VB also exhibits a stress dependence that increases when tensile stress is applied to the transistor 60 from the resin component 76 and decreases when compressive stress is applied.

[0056] Here, the voltage after the Zener voltage VZ drops by an amount equivalent to voltage VA (i.e., the amount of the first voltage) is set as voltage VZ-VA, which is equivalent to the third voltage. The voltage output by the resistor divider circuit 50 is the voltage obtained by multiplying voltage VZ-VA by the first weight and adding the voltage obtained by multiplying voltage VB by the second weight, which is used as the reference voltage Vref. Thus, the temperature dependence of the Zener voltage VZ is canceled out by the temperature dependence of voltage VA and voltage VB. In addition, the stress dependence of voltage VA and voltage VB cancel each other out. Furthermore, the stress dependence of Zener voltage VZ is canceled out by the stress dependence of voltage VA. Through the above, a reference voltage output circuit 10 can be provided that suppresses the change of reference voltage Vref caused by temperature change and suppresses the change of reference voltage Vref caused by stress change.

[0057] In contrast, as shown in Figure 3, a reference voltage output circuit 10A is considered, in which diodes 3a and 3b are connected in series between the resistor divider circuit 50 and the negative electrode 2. The anode terminal of diode 3a is connected to the resistor element 50b, and the cathode terminal is connected to the anode terminal of diode 3b. The anode terminal of diode 3b is connected to the cathode terminal of diode 3a, and the cathode terminal is connected to the negative electrode 2. In this case, the branch current Ic flows from the current source 20 through the resistor elements 50a and 50b and the diodes 3a and 3b to the negative electrode 2. At this time, a voltage VD1 caused by the PN junction of diode 3a is generated between the anode and cathode terminals of diode 3a. A voltage VD2 caused by the PN junction of diode 3b is generated between the anode and cathode terminals of diode 3b. In the Zener diode 30, the Zener voltage generated between the cathode terminal 31 and the anode terminal 32 due to the Zener effect is denoted as VZ. The voltage obtained by adding voltage VD1 and voltage VD2 is denoted as voltage VD1+VD2.

[0058] As shown in Equation 3, the resistor voltage divider circuit 50 outputs a reference voltage Vref obtained by multiplying the Zener voltage VZ by the first weight and adding the voltage obtained by multiplying the voltage VD1+VD2 by the second weight from the common connection terminal 51.

[0059] [Formula 3] The Zener voltage VZ exhibits a positive temperature dependence, meaning the higher the temperature of Zener diode 30, the larger the Zener voltage VZ becomes. The voltage VD1 between the anode and cathode terminals of diode 3a exhibits a negative temperature dependence, meaning the higher the temperature of diode 3a, the smaller the voltage VD1 becomes. The voltage VD2 between the anode and cathode terminals of diode 3b exhibits a negative temperature dependence, meaning the higher the temperature of diode 3b, the smaller the voltage VD2 becomes. Therefore, the temperature dependence of the Zener voltage is canceled out by the temperature dependence of the inter-terminal voltage of diode 3a and the temperature dependence of the inter-terminal voltage of diode 3b.

[0060] Therefore, the resistor divider circuit 50 can suppress changes in the reference voltage Vref caused by temperature variations. Furthermore, when the reference voltage output circuit 10A is configured as an integrated circuit device similar to the reference voltage output circuit 10A in the first embodiment described above, stress is sometimes applied to the Zener diode 30, diodes 3a, and 3b from the package components. In this case, the stress coefficient of the reference voltage Vref obtained by partially differentiating the reference voltage Vref from the stress can be expressed by equation 4.

[0061] [Formula 4] Here, tensile stress is represented by positive values, and compressive stress by negative values. In Equation 4, the stress coefficient of the Zener voltage VZ is positive. That is, when tensile stress is applied to the Zener diode 30 from the package component, the Zener voltage VZ increases. When compressive stress is applied to the Zener diode 30 from the package component, the Zener voltage VZ decreases. The stress coefficient of voltage VD1, obtained by partially differentiating voltage VD1 with respect to stress, is positive. Therefore, when tensile stress is applied to diode 3a from the package component, voltage VD1 increases, and when compressive stress is applied to diode 3a from the package component, voltage VD1 decreases. The stress coefficient of voltage VD2, obtained by partially differentiating voltage VD2 with respect to stress, is positive. Therefore, when tensile stress is applied to diode 3b from the package component, voltage VD2 increases, and when compressive stress is applied to diode 3b from the package component, voltage VD2 decreases. Therefore, the stress coefficient of the reference voltage Vref is positive. Therefore, the reference voltage Vref changes depending on the stress applied from the packaging components, etc.

[0062] In contrast, in the reference voltage output circuit 10 of this embodiment, as described above, the stress dependence of voltage VA and voltage VB cancel each other out, and the stress dependence of Zener voltage VZ is canceled out by the stress dependence of voltage VA. Therefore, as described above, changes in the reference voltage Vref caused by stress variations applied from the package components, etc., can be suppressed. In this embodiment with such a configuration, the following effects (a), (b), and (c) can be obtained.

[0063] (a) Transistor 40 is diode-connected by connecting base terminal 43 to collector terminal 41. Thus, in transistor 40, a voltage VA caused by the PN junction can be generated with a simple structure.

[0064] (b) Similarly, transistor 60 is diode-connected by connecting base terminal 63 to collector terminal 62. Thus, in transistor 60, a voltage VB caused by the second PN junction can be generated with a simple structure.

[0065] (c) The resistive voltage divider circuit 50 has resistive elements 50a and 50b connected in series between transistor 40 and transistor 60. For the resistive voltage divider circuit 50, the voltage obtained by dividing the voltage VZ-VA through the resistive elements 50a and 50b is obtained by multiplying the voltage VZ-VA by a weight. For the resistive voltage divider circuit 50, the voltage obtained by dividing the voltage VB through the resistive elements 50a and 50b is obtained by multiplying the voltage VB by a weight. Therefore, the voltage obtained by multiplying the voltage VZ-VA by a first weight and the voltage obtained by multiplying the voltage VB by a second weight can be easily obtained.

[0066] (Second Embodiment) In the first embodiment described above, an example of outputting a reference voltage Vref from the common connection terminal 51 of the two resistor elements 50a and 50b in the resistor voltage divider circuit 50 was explained. However, instead, this second embodiment, which uses three or more resistor elements to output a reference voltage Vref of an appropriate voltage value, will be described with reference to FIGS. 4 and 5. FIG. 4 is a circuit diagram showing the overall circuit structure of the reference voltage output circuit 10. FIG. 5 is a circuit diagram showing the detailed circuit structure of the resistor voltage divider circuit 50 in FIG. 4. The reference voltage output circuit 10 of this embodiment differs from the reference voltage output circuit 10 of the first embodiment in terms of the circuit structure of the resistor voltage divider circuit 50. Hereinafter, the resistor voltage divider circuit 50 in the reference voltage output circuit 10 of this embodiment will be mainly described. In FIG. 4, the same symbols as in FIG. 1 indicate the same parts, and their descriptions are omitted.

[0067] As shown in Figure 4, the resistor divider circuit 50 of this embodiment includes resistor elements 50a and 50f, and a switching circuit 50A. Resistor elements 50a and 50f and the switching circuit 50A are connected in series between transistors 40 and 60. Resistor element 50a is positioned between transistor 40 and the switching circuit 50A. The switching circuit 50A is positioned between resistor elements 50a and 50f. Resistor element 50f is positioned between the switching circuit 50A and the transistor 60.

[0068] As shown in Figure 5, the switching circuit 50A includes: resistors 50b, 50c, 50d, and 50e; switches SW1, SW2, SW3, SW4, and SW5; an output section 52; and a control circuit 53. Resistor elements 50b, 50c, 50d, and 50e are connected in series between resistors 50a and 50f. Therefore, resistors 50a, 50b, 50c, 50d, 50e, and 50f are arranged from transistor 40 to transistor 60 in the order of resistors 50a, 50b, 50c, 50d, 50e, and 50f. Furthermore, for ease of explanation, resistors 50a, 50b, 50c, 50d, 50e, and 50f will be collectively referred to as resistors 50a to 50f. Switches SW1, SW2, SW3, SW4, and SW5 will also be collectively referred to as switches SW1 to SW5.

[0069] Resistive elements 50a-50f constitute common connection terminals 51a, 51b, 51c, 51d, and 51e that connect adjacent resistive elements 50a-50f. Hereinafter, common connection terminals 51a, 51b, 51c, 51d, and 51e will also be collectively referred to as common connection terminals 51a-51e. Common connection terminal 51a is the terminal that commonly connects resistive elements 50a and 50b. Common connection terminal 51b is the terminal that commonly connects resistive elements 50b and 50c. Common connection terminal 51c is the terminal that commonly connects resistive elements 50c and 50d. Common connection terminal 51d is the terminal that commonly connects resistive elements 50d and 50e. Common connection terminal 51e is the terminal that commonly connects resistive elements 50e and 50f.

[0070] Switch SW1 is positioned between the common connection terminal 51a and the output unit 52. Switch SW1 connects or disconnects the common connection terminal 51a and the output unit 52. Switch SW2 is positioned between the common connection terminal 51b and the output unit 52. Switch SW2 connects or disconnects the common connection terminal 51b and the output unit 52. Switch SW3 is positioned between the common connection terminal 51c and the output unit 52. Switch SW3 connects or disconnects the common connection terminal 51c and the output unit 52. Switch SW4 is positioned between the common connection terminal 51d and the output unit 52. Switch SW4 connects or disconnects the common connection terminal 51d and the output unit 52. Switch SW5 is positioned between the common connection terminal 51e and the output unit 52. Switch SW5 connects or disconnects the common connection terminal 51e and the output unit 52.

[0071] The output unit 52 outputs the voltage between any one of the common connection terminals 51a-51e and the negative electrode 2 as the reference voltage Vref. The control circuit 53 turns on any one of the switches SW1, SW2, SW3, SW4, and SW5, and turns off the remaining four switches. Thus, the output voltage of any one of the common connection terminals 51a-51e is output from the output unit 52 as the reference voltage Vref. Next, the operation of the reference voltage output circuit 10 of this embodiment will be described with reference to FIGS. 4 and 5.

[0072] First, current source 20, based on the power supply voltage between positive electrode 1 and negative electrode 2, causes the main current Ia to flow from positive electrode 1 to negative electrode 2. A branch current Ib within the main current Ia flows from current source 20 to negative electrode 2 through Zener diode 30. Simultaneously, Zener diode 30 generates a Zener voltage VZ between current source 20 and negative electrode 2 due to the Zener effect. On the other hand, branch current Ic, excluding branch current Ib within the main current Ia, flows to negative electrode 2 through transistor 40, resistors 50a-50f, and transistor 60.

[0073] Control circuit 53 turns on any one of switches SW1 to SW5 and turns off the remaining four switches. As a result, the common connection terminal 51a to 51e corresponding to any one of the switches is connected to the output unit 52. Simultaneously, the voltage between the common connection terminal 51a to 51e corresponding to any one of the switches and the negative electrode 2 is output from the output unit 52 as a reference voltage Vref.

[0074] For example, control circuit 53 turns on switch SW3 and turns off switches SW1, SW2, SW4, and SW5. Therefore, common connection terminal 51c is connected to negative electrode 2, and common connection terminals 51a, 51b, 51d, and 51e are disconnected from negative electrode 2. Therefore, the voltage between common connection terminal 51c and negative electrode 2 is output from output unit 52 as a reference voltage Vref. Resistor voltage divider circuit 50, as shown in equation 5, outputs reference voltage Vref from common connection terminal 51c. This reference voltage Vref is obtained by multiplying the voltage VZ-VA (obtained by stepping down the Zener voltage VZ by an amount equivalent to voltage VA) by a first weight, and the voltage VB (obtained by multiplying the voltage VB by a second weight).

[0075] [Formula 5] Let the resistance value of resistor 50a be R1, the resistance value of resistor 50b be R2, the resistance value of resistor 50c be R3, the resistance value of resistor 50d be R4, the resistance value of resistor 50e be R5, and the resistance value of resistor 50f be R6. Furthermore, in equation 5, the first weight is the value obtained by dividing R4+R5+R6 by R1+R2+R3+R4+R5+R6. R1+R2+R3+R4+R5+R6 is the resistance value obtained by adding R1, R2, R3, R4, R5, and R6. R4+R5+R6 is the resistance value obtained by adding R4, R5, and R6.

[0076] The second weight is the value obtained by dividing R1+R2+R3 by R1+R2+R3+R4+R5+R6. R1+R2+R3 is the resistance value obtained by adding R1, R2, and R3. The reference voltage Vref is the voltage obtained by superimposing the voltage divided by resistors 50a, 50b, 50c, 50d, 50e, and 50f on voltage VZ-VA and the voltage divided by resistors 50a, 50b, 50c, 50d, 50e, and 50f on voltage VB. Furthermore, the stress coefficient of the reference voltage Vref, as shown in Equation 6, can be expressed by the stress coefficients of the Zener voltage VZ, voltage VA, and voltage VB.

[0077] [Formula 6] In this embodiment, similar to the first embodiment described above, transistors 40 and 60 are configured such that the stress coefficient of voltage VA is greater than the stress coefficient of voltage VB. Transistor 40 and Zener diode 30 are configured such that the stress coefficient of voltage VA is greater than the stress coefficient of Zener voltage VZ. Here, tensile stress is represented by a positive value, and compressive stress by a negative value. In this case, the value obtained by subtracting the stress coefficient of voltage VA from the stress coefficient of Zener voltage VZ is negative. The stress coefficient of voltage VB is positive. Therefore, as shown in Formula 6, the stress coefficient of the reference voltage Vref can be made close to zero.

[0078] In this embodiment, as described above, the resistor divider circuit 50 adds the voltage obtained by multiplying voltage VZ-VA by a first weight and the voltage obtained by multiplying voltage VB by a second weight, and uses the resulting voltage as the reference voltage Vref. Thus, the temperature dependence of the Zener voltage VZ is canceled out by the temperature dependence of voltage VA and voltage VB. Furthermore, the stress dependence of voltage VA and voltage VB cancels out, and the stress dependence of the Zener voltage VZ is canceled out by the stress dependence of voltage VA.

[0079] According to the embodiment described above, the resistor divider circuit 50 includes resistor elements 50a-50f, an output section 52 that outputs a reference voltage Vref, and switches SW1-SW5. The resistor elements 50a-50f form common connection terminals 51a-51f that connect adjacent resistor elements 50a-50f in a common manner. Switches SW1-SW5 connect any one of the common connection terminals 51a-51f to the output section 52, and disconnect the remaining common connection terminals (other than the one mentioned above) from the output section 52.

[0080] Therefore, the reference voltage output circuit 10 outputs the voltage between any one of the common connection terminals 51a-51f and the negative electrode 2 as a reference voltage Vref from the output unit 52. Thus, by outputting the output voltage of any one of the common connection terminals 51a-51f from the output unit 52 as the reference voltage Vref, a reference voltage Vref of an appropriate voltage value can be output from the output unit 52.

[0081] (Third Embodiment) In the first embodiment described above, an example was described in which a transistor 60 was disposed between the resistor divider circuit 50 and the negative electrode 2 as a second semiconductor unit in the reference voltage output circuit 10. However, instead, this third embodiment, in which a Zener diode 60a is disposed between the resistor divider circuit 50 and the negative electrode 2 as a second semiconductor unit in the reference voltage output circuit 10, will be described with reference to FIG6.

[0082] Figure 6 is a circuit diagram showing the circuit structure of the reference voltage output circuit 10 of this embodiment. In Figure 6, the same symbols as in Figure 1 denote the same parts, and their descriptions are omitted. As shown in Figure 6, the reference voltage output circuit 10 of this embodiment uses a Zener diode 60a instead of a transistor 60. The Zener diode 60a has an anode terminal 61a connected to the resistor divider circuit 50 as a second input terminal, and a cathode terminal 62a connected to the negative electrode 2 as a second output terminal.

[0083] The Zener diode 60a is a second semiconductor section comprising a P-type semiconductor and an N-type semiconductor. The P-type semiconductor is a second P-type semiconductor disposed between the resistor voltage divider circuit 50 and the negative electrode 2. An anode terminal 61a is connected to the P-type semiconductor. The N-type semiconductor is a second N-type semiconductor disposed between the P-type semiconductor and the negative electrode 2. The N-type semiconductor and the P-type semiconductor are in contact to form a second PN junction. A cathode terminal is connected to the N-type semiconductor. Furthermore, the circuit structure of the reference voltage output circuit 10 in this embodiment, except for the Zener diode 60a, is the same as that of the reference voltage output circuit 10 in the first embodiment described above.

[0084] Next, the operation of the reference voltage output circuit 10 of this embodiment will be described with reference to FIG6. First, the current source 20 causes the main current Ia to flow from the positive electrode 1 to the negative electrode 2 based on the power supply voltage between the positive electrode 1 and the negative electrode 2. In addition, the branch current Ib in the main current Ia flows from the current source 20 to the negative electrode 2 through the Zener diode 30. Accompanying this, the Zener diode 30 generates a Zener voltage VZ caused by the Zener effect between the current source 20 and the negative electrode 2. On the other hand, the branch current Ic flows from the current source 20 to the negative electrode 2 through the transistor 40, the resistor elements 50a and 50b, and the Zener diode 60a.

[0085] Similar to the first embodiment described above, the branch current Ic flows from the collector terminal 41 of the transistor 40 through the first PN junction to the emitter terminal 42. Therefore, a voltage VA caused by the first PN junction is generated between the collector terminal 41 and the emitter terminal 42. The branch current Ic flows between the anode terminal 61a and the cathode terminal 62a through the second PN junction of the Zener diode 60a. Thus, a voltage VB caused by the second PN junction is generated between the anode terminal 61a and the cathode terminal 62a.

[0086] The voltage VB exhibits temperature dependence. This temperature dependence is negative, meaning that VB decreases as the temperature of the Zener diode 60a increases, and increases as the temperature of the Zener diode 60a decreases. The voltage VB also exhibits stress dependence. This stress dependence is positive, meaning that VB increases when tensile stress is applied to the Zener diode 60a by the resin component 76, and decreases when compressive stress is applied to the Zener diode 60a by the resin component 76. In other words, the voltage VB in this embodiment has the same temperature and stress dependence as the voltage VB in the first embodiment described above.

[0087] Similar to the first embodiment described above, the resistive voltage divider circuit 50 outputs a reference voltage Vref from the common connection terminal 51. This reference voltage Vref is obtained by multiplying the voltage VZ-VA (obtained by stepping down the Zener voltage VZ by an amount equivalent to voltage VA) by a first weight, and the voltage VB by a second weight. Thus, the temperature dependence of the Zener voltage VZ is canceled out by the temperature dependence of voltage VA and voltage VB. Furthermore, the stress dependence of voltage VA and voltage VB cancels out, and the stress dependence of the Zener voltage VZ is canceled out by the stress dependence of voltage VA.

[0088] According to the embodiment described above, the reference voltage output circuit 10 includes a Zener diode 60a instead of the transistor 60 of the first embodiment. The Zener diode 60a has a P-type semiconductor disposed between the anode terminal 61a and the cathode terminal 62a. The Zener diode 60a also has an N-type semiconductor disposed between the P-type semiconductor and the cathode terminal 62a, and in contact with the P-type semiconductor to form a second PN junction. A branch current Ic flows through the second PN junction between the emitter terminal 61 and the collector terminal 62 of the transistor 60, thereby generating a voltage VB caused by the second PN junction between the emitter terminal 61 and the collector terminal 62. The Zener diode 30, the transistor 40, and the Zener diode 60a are each covered by a resin component 76.

[0089] The Zener voltage VZ exhibits the same temperature and stress dependence as in the first embodiment described above. The voltage VA also exhibits the same temperature and stress dependence as in the first embodiment described above. The voltage VB exhibits the same temperature and stress dependence as in the first embodiment described above. The resistor divider circuit 50 outputs a voltage obtained by multiplying voltage VZ - VA by a first weight and adding the voltage obtained by multiplying voltage VB by a second weight, which serves as the reference voltage Vref. Thus, the temperature dependence of voltage VA and voltage VB cancels out, and the stress dependence of the Zener voltage VZ is canceled out by the stress dependence of voltage VA. Through the above, a reference voltage output circuit 10 can be provided that suppresses changes in the reference voltage Vref caused by temperature variations and suppresses changes in the reference voltage Vref caused by stress variations.

[0090] (Fourth Embodiment) In the first embodiment described above, an example was described in which a transistor 60 was arranged between the resistor divider circuit 50 and the negative electrode 2 in the reference voltage output circuit 10. However, instead, this fourth embodiment, in which diodes 60b and 60c are arranged in parallel between the resistor divider circuit 50 and the negative electrode 2 in the reference voltage output circuit 10, will be described with reference to FIG7.

[0091] Figure 7 is a circuit diagram showing the circuit structure of the reference voltage output circuit 10 of this embodiment. In Figure 7, the same symbols as in Figure 1 denote the same parts, and their descriptions are omitted. As shown in Figure 7, the reference voltage output circuit 10 of this embodiment uses diodes 60b and 60c instead of transistor 60. Diode 60b has an anode terminal connected to the resistor divider circuit 50 as a second input terminal and a cathode terminal connected to the negative electrode 2 as a second output terminal. Diode 60c has an anode terminal connected to the resistor divider circuit 50 as a second input terminal and a cathode terminal connected to the negative electrode 2 as a second output terminal.

[0092] Diodes 60b and 60c are semiconductor elements connected in parallel between the resistor divider circuit 50 and the negative electrode 2. Diodes 60b and 60c constitute the second semiconductor section 60X. The anode terminal of diode 60b and the anode terminal of diode 60c are connected in a common manner to form the input terminal 61x of the second semiconductor section 60X. The cathode terminal of diode 60b and the cathode terminal of diode 60c are connected in a common manner to form the output terminal 62x of the second semiconductor section 60X.

[0093] Diode 60b comprises a P-type semiconductor and an N-type semiconductor. The P-type semiconductor is disposed between the resistor divider circuit 50 and the negative electrode 2. An anode terminal is connected to the P-type semiconductor. An N-type semiconductor is disposed between the P-type semiconductor and the negative electrode 2. The N-type semiconductor and the P-type semiconductor are in contact to form a second PN junction. A cathode terminal is connected to the N-type semiconductor. Diode 60c comprises a P-type semiconductor and an N-type semiconductor. The P-type semiconductor is disposed between the resistor divider circuit 50 and the negative electrode 2. An anode terminal is connected to the P-type semiconductor. An N-type semiconductor is disposed between the P-type semiconductor and the negative electrode 2. The N-type semiconductor and the P-type semiconductor are in contact to form a second PN junction. A cathode terminal is connected to the N-type semiconductor.

[0094] Furthermore, the P-type semiconductors of diode 60b and diode 60c respectively constitute second P-type semiconductors. The N-type semiconductors of diode 60b and diode 60c respectively constitute second N-type semiconductors. The circuit structure of the reference voltage output circuit 10 in this embodiment, except for diodes 60b and 60c, is the same as that of the reference voltage output circuit 10 in the first embodiment described above. Next, the operation of the reference voltage output circuit 10 of this embodiment will be described with reference to FIG7.

[0095] First, current source 20, based on the power supply voltage between positive electrode 1 and negative electrode 2, causes the main current Ia to flow from positive electrode 1 to negative electrode 2. A branch current Ib within the main current Ia flows from current source 20 to negative electrode 2 through Zener diode 30. Accompanying this, Zener diode 30 generates a Zener voltage VZ between current source 20 and negative electrode 2 due to the Zener effect. On the other hand, branch current Ic flows from current source 20 to negative electrode 2 through transistor 40, resistors 50a and 50b, and diodes 60b and 60c.

[0096] Specifically, a portion of the branch current Ic flows through diode 60b. The remaining current, excluding a portion of the branch current Ic, flows through diode 60c. That is, current flows from the resistor divider circuit 50 to diodes 60b and 60c, respectively. Consequently, a voltage VB, caused by the first PN junction and the second PN junction, is generated between the input terminal 61x and the output terminal 62x of the second semiconductor section 60X. In the reference voltage output circuit 10 of FIG7, the voltage generated between the terminals due to the second PN junction of diode 60b is defined as voltage VB1. "Between terminals" refers to the sum of the currents between the anode and cathode terminals of diode 60b.

[0097] In the reference voltage output circuit 10 of Figure 7, the voltage generated between the terminals due to the second PN junction of diode 60c is set as voltage VB2. "Between the terminals" refers to the area between the anode and cathode terminals of diode 60c. In this embodiment, based on the current-voltage characteristics of the second PN junctions of diodes 60b and 60c, current flows from the resistor divider circuit 50 to diodes 60b and 60c so that voltages VB1 and VB2 become the same voltage (i.e., voltage VB).

[0098] Voltage VB1 exhibits temperature dependence. This temperature dependence is negative, meaning that voltage VB1 decreases when the temperature of diode 60b increases and increases when the temperature of diode 60b decreases. Voltage VB2 also exhibits temperature dependence. This temperature dependence is negative, meaning that voltage VB2 decreases when the temperature of diode 60c increases and increases when the temperature of diode 60c decreases. Therefore, voltage VB exhibits a negative temperature dependence, meaning that voltage VB decreases when the temperature of diodes 60b and 60c increases and increases when the temperature of diodes 60b and 60c decreases. In other words, voltage VB in this embodiment has the same temperature dependence as voltage VB in the first embodiment described above.

[0099] Voltage VB1 exhibits stress dependence. This stress dependence is a positive stress dependence, where voltage VB1 increases when tensile stress is applied from resin component 76 to diode 60b, and decreases when compressive stress is applied from resin component 76 to diode 60b. Voltage VB2 also exhibits stress dependence. This stress dependence is a positive stress dependence, where voltage VB2 increases when tensile stress is applied from resin component 76 to diode 60c, and decreases when compressive stress is applied from resin component 76 to diode 60c. In other words, the voltage VB in this embodiment exhibits the same stress dependence as the voltage VB in the first embodiment described above.

[0100] The resistor divider circuit 50 in this embodiment, similar to that in the first embodiment described above, outputs a reference voltage Vref from the common connection terminal 51. This reference voltage is obtained by adding the voltage obtained by multiplying the voltage VZ-VA by a first weight and the voltage obtained by multiplying the voltage VB by a second weight. Therefore, the temperature dependence of the Zener voltage VZ is canceled out by the temperature dependence of the voltage VA and the voltage VB. Furthermore, the stress dependence of the voltage VA and the stress dependence of the voltage VB are canceled out, and the stress dependence of the Zener voltage VZ is canceled out by the stress dependence of the voltage VA.

[0101] The reference voltage output circuit 10 of this embodiment described above uses diodes 60b and 60c instead of the transistor 60 of the first embodiment. Diodes 60b and 60c form a second semiconductor section 60X connected in parallel between the resistor divider circuit 50 and the negative electrode 2. A voltage VB is generated between the input terminal 61x and the output terminal 62x of the second semiconductor section 60X, which is the average of voltages VB1 and VB2.

[0102] The voltage VA in this embodiment has the same temperature dependence and stress dependence as the voltage VA in the first embodiment described above. The voltage VB in this embodiment has a negative temperature dependence, decreasing when the temperature of diodes 60b and 60c rises and increasing when the temperature of diodes 60b and 60c falls. The voltage VB has a stress dependence, increasing when tensile stress is applied to diodes 60b and 60c from the resin component 76 and decreasing when compressive stress is applied to diodes 60b and 60c from the resin component 76. In this embodiment, similarly to the above embodiment, the resistor divider circuit 50 outputs a reference voltage Vref from the output unit 52, obtained by adding the voltage VZ-VA multiplied by a first weight to the voltage VB multiplied by a second weight.

[0103] Therefore, similarly to the first embodiment described above, the temperature dependence of the Zener voltage VZ is canceled out by the temperature dependence of the voltage VA and the temperature dependence of the voltage VB. Furthermore, the stress dependence of the voltage VA and the stress dependence of the voltage VB cancel each other out, and the stress dependence of the Zener voltage VZ is canceled out by the stress dependence of the voltage VA. Through the above, a reference voltage output circuit 10 that suppresses changes in the reference voltage caused by temperature variations and changes in the reference voltage caused by stress variations can be provided.

[0104] (Fifth Embodiment) In the third embodiment described above, an example was given in which a transistor 40 was arranged between the current source 20 and the resistor divider circuit 50 in the reference voltage output circuit 10. However, instead, this fifth embodiment will be described with reference to FIG8, in which diodes 40a and 40b are connected in parallel between the current source 20 and the resistor divider circuit 50 in the reference voltage output circuit 10. FIG8 is a circuit diagram showing the circuit structure of the reference voltage output circuit 10 of this embodiment. In FIG8, the same symbols as in FIG6 denote the same parts, and their descriptions are omitted.

[0105] As shown in Figure 8, the reference voltage output circuit 10 of this embodiment uses diodes 40a and 40b instead of transistor 40. Diode 40a has an anode terminal connected to the current source 20 as a first input terminal and a cathode terminal connected to the resistor divider circuit 50 as a first output terminal. Diode 40b has an anode terminal connected to the current source 20 as a first input terminal and a cathode terminal connected to the resistor divider circuit 50 as a first output terminal. Diodes 40a and 40b are semiconductor elements connected in parallel between the current source 20 and the negative electrode 2. Diodes 40a and 40b constitute the first semiconductor section 40X.

[0106] The anode terminal of diode 40a and the anode terminal of diode 40b are connected in a common manner to form the input terminal 41x of the first semiconductor section 40X. The cathode terminal of diode 40a and the cathode terminal of diode 40b are connected in a common manner to form the output terminal 42x of the first semiconductor section 40X. Diode 40a includes a P-type semiconductor and an N-type semiconductor. The P-type semiconductor is disposed between the current source 20 and the resistor voltage divider circuit 50. An anode terminal is connected to the P-type semiconductor. The N-type semiconductor is disposed between the P-type semiconductor and the resistor voltage divider circuit 50. The N-type semiconductor and the P-type semiconductor are in contact to form a first PN junction. A cathode terminal is connected to the N-type semiconductor.

[0107] Diode 40b comprises a P-type semiconductor and an N-type semiconductor. The P-type semiconductor is disposed between the current source 20 and the resistor divider circuit 50. An anode terminal is connected to the P-type semiconductor. An N-type semiconductor is disposed between the P-type semiconductor and the resistor divider circuit 50. The N-type semiconductor and the P-type semiconductor are in contact to form a first PN junction. A cathode terminal is connected to the N-type semiconductor. Furthermore, the P-type semiconductors of diodes 40a and 40b respectively constitute first P-type semiconductors. The N-type semiconductors of diodes 40a and 40b respectively constitute first N-type semiconductors. The circuit structure of the reference voltage output circuit 10 in this embodiment, excluding diodes 40a and 40b, is the same as that of the reference voltage output circuit 10 in the third embodiment described above.

[0108] Next, the operation of the reference voltage output circuit 10 of this embodiment will be described with reference to FIG8. First, the current source 20 causes the main current Ia to flow from the positive electrode 1 to the negative electrode 2 based on the power supply voltage between the positive electrode 1 and the negative electrode 2. The branch current Ib flows from the current source 20 to the negative electrode 2 through the Zener diode 30. Accompanyingly, the Zener diode 30 generates a Zener voltage VZ caused by the Zener effect between the current source 20 and the negative electrode 2. On the other hand, the branch current Ic flows from the current source 20 to the negative electrode 2 through diodes 40a, 40b, resistors 50a, 50b, diodes 60b, and 60c. Specifically, a portion of the branch current Ic flows through diode 40a. The remaining current other than a portion of the branch current Ic flows through diode 40b.

[0109] Consequently, a voltage VA caused by the first PN junctions of diodes 40a and 40b is generated between the input terminal 41x and the output terminal 42x of the first semiconductor section 40X. In the reference voltage output circuit 10 of FIG8, the voltage generated between the terminals due to the first PN junction of diode 40a is defined as voltage VA1. "Between terminals" refers to the sum of the voltages between the anode and cathode terminals of diode 40a. In the reference voltage output circuit 10 of FIG8, the voltage generated between the terminals due to the first PN junction of diode 40b is defined as voltage VA2. "Between terminals" refers to the sum of the voltages between the anode and cathode terminals of diode 40b. In this embodiment, based on the current-voltage characteristics of the first PN junctions of diodes 40a and 40b, current flows from the current source 20 to diodes 40a and 40b so that voltages VA1 and VA2 become the same voltage (i.e., voltage VA).

[0110] Voltage VA1 exhibits temperature dependence. This temperature dependence is negative, meaning that voltage VA1 decreases when the temperature of diode 40a increases and increases when the temperature of diode 40a decreases. Voltage VA2 also exhibits temperature dependence. This temperature dependence is negative, meaning that voltage VA2 decreases when the temperature of diode 40b increases and increases when the temperature of diode 40b decreases. Voltage VA exhibits a negative temperature dependence, meaning that voltage VA decreases when the temperature of diodes 40a and 40b increases and increases when the temperature of diodes 40a and 40b decreases. That is, voltage VA in this embodiment exhibits the same temperature dependence as voltage VA in the first embodiment described above. Voltage VA1 also exhibits stress dependence. This stress dependence is positive, meaning that voltage VA1 increases when tensile stress is applied to diode 40a from resin component 76 and decreases when compressive stress is applied to diode 40a from resin component 76. Voltage VA2 also exhibits stress dependence. The stress dependence is a positive stress dependence where voltage VA2 increases when tensile stress is applied from resin component 76 to diode 40b, and decreases when compressive stress is applied from resin component 76 to diode 40b. Voltage VA exhibits a positive stress dependence where voltage VA increases when tensile stress is applied from resin component 76 to diodes 40a and 40b, and decreases when compressive stress is applied from resin component 76 to diodes 40a and 40b. That is, the voltage VA in this embodiment has the same stress dependence as the voltage VA in the third embodiment described above.

[0111] Similar to the first embodiment described above, the resistor divider circuit 50 outputs from the output unit 52 a voltage obtained by multiplying voltage VZ-VA by a first weight and the voltage obtained by multiplying voltage VB by a second weight, which serves as the reference voltage Vref. Thus, the temperature dependence of the Zener voltage VZ is canceled out by the temperature dependence of voltage VA and voltage VB. Furthermore, the stress dependence of voltage VA and voltage VB cancels out, and the stress dependence of the Zener voltage VZ is canceled out by the stress dependence of voltage VA.

[0112] The reference voltage output circuit 10 of this embodiment described above replaces the transistor 40 of the third embodiment with diodes 40a and 40b. Diodes 40a and 40b form a first semiconductor section 40X connected in parallel between the current source 20 and the resistor divider circuit 50. A voltage VA caused by the first PN junction of each of the diodes 40a and 40b is generated between the input terminal 41x and the output terminal 42x of the first semiconductor section 40X. The voltage VA has a negative temperature dependence, which decreases when the temperature of the diodes 40a and 40b rises and increases when the temperature of the diodes 40a and 40b falls. The voltage VA has a positive stress dependence, which increases when tensile stress is applied to the diodes 40a and 40b from the resin component 76 and decreases when compressive stress is applied to the diodes 40a and 40b from the resin component 76. The voltage VA of this embodiment has the same temperature dependence and stress dependence as the voltage VA of the third embodiment described above.

[0113] The resistor divider circuit 50 in this embodiment, like the third embodiment described above, outputs from the output unit 52 a voltage obtained by multiplying voltage VZ-VA by a first weight and the voltage obtained by multiplying voltage VB by a second weight, as the reference voltage Vref. Therefore, similar to the third embodiment, the temperature dependence of the Zener voltage VZ is canceled out by the temperature dependence of voltage VA and voltage VB. The stress dependence of voltage VA and voltage VB cancels out, and the stress dependence of Zener voltage VZ is canceled out by the stress dependence of voltage VA. Through the above, a reference voltage output circuit 10 that suppresses changes in the reference voltage caused by temperature variations and changes in the reference voltage caused by stress variations can be provided.

[0114] (Sixth Embodiment) In the third embodiment described above, an example was given in which a transistor 40 was arranged between the current source 20 and the resistor divider circuit 50 in the reference voltage output circuit 10. However, instead, this sixth embodiment will be described with reference to FIG9, in which diodes 40c and 40d are connected in series between the current source 20 and the resistor divider circuit 50 in the reference voltage output circuit 10. FIG9 is a circuit diagram showing the circuit structure of the reference voltage output circuit 10 of this embodiment. In FIG9, the same symbols as in FIG6 denote the same parts, and their descriptions are omitted. As shown in FIG9, the reference voltage output circuit 10 of this embodiment uses diodes 40c and 40d instead of transistor 40.

[0115] Diode 40c has an anode terminal connected to current source 20 and a cathode terminal connected to the anode terminal of diode 40d. Diode 40d has an anode terminal 41b connected to the cathode terminal of diode 40c and a cathode terminal connected to resistor divider circuit 50. Diodes 40c and 40d are semiconductor elements connected in series between current source 20 and resistor divider circuit 50. Diodes 40c and 40d constitute a first semiconductor section 40Z. The anode terminal of diode 40c constitutes the input terminal 41z of the first semiconductor section 40Z. The cathode terminal of diode 40d constitutes the output terminal 42z of the first semiconductor section 40Z.

[0116] Diode 40c includes a P-type semiconductor and an N-type semiconductor. The P-type semiconductor is disposed between the current source 20 and diode 40d. An anode terminal is connected to the P-type semiconductor. An N-type semiconductor is disposed between the P-type semiconductor and diode 40d. The N-type semiconductor and P-type semiconductor are in contact to form a first PN junction. A cathode terminal is connected to the N-type semiconductor. Diode 40d includes a P-type semiconductor and an N-type semiconductor. The P-type semiconductor is disposed between diode 40c and resistor divider circuit 50. An anode terminal is connected to the P-type semiconductor. The N-type semiconductor is disposed between the P-type semiconductor and resistor divider circuit 50. Furthermore, the N-type semiconductor and P-type semiconductor are in contact to form a first PN junction. A cathode terminal is connected to the N-type semiconductor. The circuit structure of the reference voltage output circuit 10 in this embodiment, except for diodes 40c and 40d, is the same as that of the reference voltage output circuit 10 in the third embodiment described above.

[0117] Next, the operation of the reference voltage output circuit 10 of this embodiment will be described with reference to FIG9. First, the current source 20 causes the main current Ia to flow from the positive electrode 1 to the negative electrode 2 based on the power supply voltage between the positive electrode 1 and the negative electrode 2. The branch current Ib flows from the current source 20 to the negative electrode 2 through the Zener diode 30. Accompanyingly, the Zener diode 30 generates a Zener voltage VZ caused by the Zener effect between the current source 20 and the negative electrode 2. On the other hand, the branch current Ic flows from the current source 20 to the negative electrode 2 through diodes 40c and 40d, resistors 50a and 50b, and Zener diode 60a.

[0118] At this time, a voltage VA1a caused by the first PN junction of diode 40c is generated between the anode terminal and the cathode terminal 42c of diode 40c. A voltage VA2a caused by the first PN junction of diode 40d is generated between the anode terminal 41d and the cathode terminal of diode 40d. In this embodiment, a voltage VA obtained by adding voltage VA1a and voltage VA2a is generated between the input terminal 41x and the output terminal 42x of the first semiconductor section 40X.

[0119] Voltage VA1a exhibits temperature dependence. This temperature dependence is negative, meaning that voltage VA1a decreases as the temperature of diode 40c increases and increases as the temperature of diode 40c decreases. Voltage VA2a also exhibits temperature dependence. This temperature dependence is negative, meaning that voltage VA2a decreases as the temperature of diode 40d increases and increases as the temperature of diode 40d decreases. Voltage VA exhibits the same negative temperature dependence, meaning that voltage VA decreases as the temperatures of diodes 40c and 40d increase as the temperatures of diodes 40c and 40d decrease. In other words, voltage VA in this embodiment has the same temperature dependence as voltage VA in the first embodiment described above.

[0120] Voltage VA1a exhibits stress dependence. This stress dependence is a positive stress dependence, where voltage VA1a increases when tensile stress is applied from resin component 76 to diode 40c, and decreases when compressive stress is applied from resin component 76 to diode 40c. Voltage VA2a also exhibits stress dependence. This stress dependence is a positive stress dependence, where voltage VA2a increases when tensile stress is applied from resin component 76 to diode 40d, and decreases when compressive stress is applied from resin component 76 to diode 40d. Voltage VA exhibits a positive stress dependence, where voltage VA increases when tensile stress is applied from resin component 76 to diodes 40c and 40d, and decreases when compressive stress is applied from resin component 76 to diodes 40c and 40d. In other words, the voltage VA in this embodiment exhibits the same stress dependence as the voltage VA in the first embodiment described above.

[0121] The resistor divider circuit 50 in this embodiment, similar to that in the third embodiment described above, outputs a reference voltage Vref from the common connection terminal 51. This voltage is obtained by multiplying voltage VZ-VA by a first weight and voltage VB by a second weight. Thus, the temperature dependence of the Zener voltage VZ is canceled out by the temperature dependence of voltage VA and voltage VB. Furthermore, the stress dependence of voltage VA and voltage VB cancels out, and the stress dependence of the Zener voltage VZ is canceled out by the stress dependence of voltage VA.

[0122] The reference voltage output circuit 10 of this embodiment, as described above, includes diodes 40c and 40d instead of transistor 40. Diode 40c has an anode terminal connected to current source 20 and a cathode terminal connected to diode 40d. Diode 40d has an anode terminal connected to diode 40c and a cathode terminal connected to resistor divider circuit 50. Diodes 40c and 40d are connected in series between current source 20 and resistor divider circuit 50 to form a first semiconductor section 40Z. A voltage VA, which is the sum of voltages VA1 and VA2, is generated between the input terminal 41z and the output terminal 42z of the first semiconductor section 40Z.

[0123] The voltage VA exhibits a negative temperature dependence, decreasing as the temperature of diodes 40c and 40d increases, and increasing as the temperature of diodes 40c and 40d decreases. The voltage VA also exhibits a positive stress dependence, increasing when tensile stress is applied to diodes 40c and 40d from the resin component 76, and decreasing when compressive stress is applied to diodes 40c and 40d from the resin component 76. The voltage VB in this embodiment exhibits the same temperature and stress dependence as the voltage VB in the third embodiment described above. Similar to the third embodiment, the resistor divider circuit 50 in this embodiment outputs from the output unit 52 a voltage obtained by multiplying voltage VZ-VA by a first weight and a voltage obtained by multiplying voltage VB by a second weight, which serves as a reference voltage Vref.

[0124] Therefore, similarly to the third embodiment described above, the temperature dependence of the Zener voltage VZ is canceled out by the temperature dependence of the voltage VA and the temperature dependence of the voltage VB. The stress dependence of the voltage VA and the stress dependence of the voltage VB cancel each other out, and the stress dependence of the Zener voltage VZ is canceled out by the stress dependence of the voltage VA. Through the above, a reference voltage output circuit 10 that suppresses changes in the reference voltage caused by temperature variations and changes in the reference voltage caused by stress variations can be provided.

[0125] (Seventh Embodiment) In the fourth embodiment described above, an example was described in which diodes 60b and 60c were connected in parallel between the resistor divider circuit 50 and the negative electrode 2 in the reference voltage output circuit 10. However, instead, this seventh embodiment will be described with reference to FIG10, in which diodes 60e and 60f are connected in series between the resistor divider circuit 50 and the negative electrode 2 in the reference voltage output circuit 10.

[0126] Figure 10 is a circuit diagram showing the circuit structure of the reference voltage output circuit 10 of this embodiment. In Figure 10, the same symbols as in Figure 7 denote the same parts, and their descriptions are omitted. As shown in Figure 10, the reference voltage output circuit 10 of this embodiment has diodes 60e and 60f instead of diodes 60b and 60c. Diodes 60e and 60f are semiconductor elements connected in series between the resistor voltage divider circuit 50 and the negative electrode 2. Diodes 60e and 60f constitute the second semiconductor section 60Z.

[0127] Diode 60e has an anode terminal connected to the resistor divider circuit 50 and a cathode terminal connected to the anode terminal of diode 60f. The anode terminal of diode 60e constitutes the input terminal 61z of the second semiconductor section 60Z. Diode 60f has an anode terminal connected to the cathode terminal of diode 60e and a cathode terminal connected to the negative electrode 2. The cathode terminal of diode 60f constitutes the output terminal 62z of the second semiconductor section 60Z.

[0128] As shown in Figure 10, diode 60e has a P-type semiconductor and an N-type semiconductor. The P-type semiconductor is disposed between the resistor divider circuit 50 and diode 60f. An anode terminal is connected to the P-type semiconductor. An N-type semiconductor is disposed between the P-type semiconductor and the negative electrode 2. The N-type semiconductor and the P-type semiconductor are in contact to form a second PN junction. A cathode terminal is connected to the N-type semiconductor. Diode 60f has a P-type semiconductor and an N-type semiconductor. The P-type semiconductor is disposed between diode 60e and the negative electrode 2. An anode terminal is connected to the P-type semiconductor. The N-type semiconductor is disposed between the P-type semiconductor and the negative electrode 2. The N-type semiconductor and the P-type semiconductor are in contact to form a second PN junction. A cathode terminal is connected to the N-type semiconductor. The P-type semiconductors of diode 60f and diode 60e respectively constitute a second P-type semiconductor. The N-type semiconductors of diode 60f and diode 60e respectively constitute a second N-type semiconductor.

[0129] As shown in Figure 10, the reference voltage output circuit 10 of this embodiment uses a Zener diode 40f instead of a transistor 40. The Zener diode 40f has an anode terminal 41f connected to the current source 20 as a first input terminal, and a cathode terminal 42f connected to the resistor divider circuit 50 as a first output terminal. The Zener diode 40f has a P-type semiconductor and an N-type semiconductor. The P-type semiconductor is a first P-type semiconductor disposed between the resistor divider circuit 50 and the negative electrode 2. The P-type semiconductor is connected to the anode terminal 41f. The N-type semiconductor is disposed between the P-type semiconductor and the negative electrode 2. The N-type semiconductor and the P-type semiconductor are in contact to form a first PN junction. The N-type semiconductor is a first N-type semiconductor connected to the cathode terminal 42f. The circuit structure of the reference voltage output circuit 10 of this embodiment, except for the Zener diode 40f, diodes 60e and 60f, is the same as that of the reference voltage output circuit 10 of the fourth embodiment described above.

[0130] Next, the operation of the reference voltage output circuit 10 of this embodiment will be described with reference to FIG10. First, the current source 20 causes the main current Ia to flow from the positive electrode 1 to the negative electrode 2 based on the power supply voltage between the positive electrode 1 and the negative electrode 2. Accompanying this, the branch current Ib flows from the current source 20 to the negative electrode 2 through the Zener diode 30. Therefore, the Zener diode 30 generates a Zener voltage VZ caused by the Zener effect between the current source 20 and the negative electrode 2. On the other hand, the branch current Ic flows from the current source 20 to the negative electrode 2 through the Zener diode 40f, the resistor elements 50a and 50b, and the diodes 60e and 60f.

[0131] A voltage VA caused by the first PN junction is generated between the anode terminal 41f and the cathode terminal 42f of the Zener diode 40f. A voltage VB1a caused by the second PN junction of the diode 60e is generated between the anode terminal and the cathode terminal of the diode 60e. A voltage VB2a caused by the second PN junction of the diode 60f is generated between the anode terminal and the cathode terminal of the diode 60f. Simultaneously, a voltage VB, obtained by adding voltages VB1a and VB2a, is generated between the input terminal 61z and the output terminal 62z of the second semiconductor section 60Z.

[0132] The voltage VA exhibits a temperature dependence. This temperature dependence is negative, meaning that the voltage VA decreases as the temperature of the Zener diode 40f increases, and increases as the temperature of the Zener diode 40f decreases. In other words, the voltage VA in this embodiment has the same temperature dependence as the voltage VA in the fourth embodiment described above. The voltage VA also exhibits a stress dependence. This stress dependence is positive, meaning that the voltage VA increases when tensile stress is applied to the Zener diode 40f from the resin component 76, and decreases when compressive stress is applied to the Zener diode 40f from the resin component 76. In other words, the voltage VA in this embodiment has the same stress dependence as the voltage VA in the fourth embodiment described above.

[0133] Voltage VB1a exhibits temperature dependence. This temperature dependence is negative, meaning that voltage VB1a decreases as the temperature of diode 60e increases, and increases as the temperature of diode 60e decreases. Voltage VB2a also exhibits temperature dependence. This temperature dependence is negative, meaning that voltage VB2a decreases as the temperature of diode 60f increases, and increases as the temperature of diode 60f decreases. Therefore, voltage VB exhibits a negative temperature dependence, meaning that voltage VB decreases as the temperature of diodes 60e and 60f increases, and increases as the temperature of diodes 60e and 60f decreases. In other words, voltage VB in this embodiment has the same temperature dependence as voltage VB in the fourth embodiment described above.

[0134] Voltage VB1a exhibits stress dependence. This stress dependence is a positive stress dependence, where voltage VB1a increases when tensile stress is applied from resin component 76 to diode 60e, and decreases when compressive stress is applied from resin component 76 to diode 60e. Voltage VB2a also exhibits stress dependence. This stress dependence is a positive stress dependence, where voltage VB2a increases when tensile stress is applied from resin component 76 to diode 60f, and decreases when compressive stress is applied from resin component 76 to diode 60f. Therefore, voltage VB exhibits a stress dependence where voltage VB increases when tensile stress is applied from resin component 76 to diodes 60e and 60f, and decreases when compressive stress is applied from resin component 76 to diodes 60e and 60f. In other words, voltage VB in this embodiment exhibits the same stress dependence as voltage VB in the fourth embodiment described above.

[0135] The resistor divider circuit 50 in this embodiment, similar to that in the fourth embodiment described above, outputs a reference voltage Vref from the common connection terminal 51. This voltage is obtained by multiplying voltage VZ-VA by a first weight and voltage VB by a second weight. Thus, the temperature dependence of the Zener voltage VZ is canceled out by the temperature dependence of voltage VA and voltage VB. Furthermore, the stress dependence of voltage VA and voltage VB cancels out, and the stress dependence of the Zener voltage VZ is canceled out by the stress dependence of voltage VA.

[0136] The reference voltage output circuit 10 of this embodiment described above uses a Zener diode 40f instead of a transistor 40. The Zener diode 40f has an anode terminal 41f connected to the current source 20 and a cathode terminal 42f connected to the resistor divider circuit 50. A voltage VA caused by the first PN junction of the Zener diode 40f is generated between the anode terminal 41f and the cathode terminal 42f. The voltage VA exhibits a negative temperature dependence, decreasing as the temperature of the Zener diode 40f increases and increasing as the temperature of the Zener diode 40f decreases. The voltage VA also exhibits a positive stress dependence, increasing when tensile stress is applied to the Zener diode 40f from the resin component 76 and decreasing when compressive stress is applied to the Zener diode 40f from the resin component 76.

[0137] The reference voltage output circuit 10 includes diodes 60e and 60f instead of diodes 60b and 60c. Diode 60e has an anode terminal connected to the resistor divider circuit 50 and a cathode terminal connected to the anode terminal of diode 60f. Diode 60f has an anode terminal connected to the cathode terminal of diode 60e and a cathode terminal connected to the negative electrode 2. Diodes 60e and 60f are connected in series between the resistor divider circuit 50 and the negative electrode 2 to form a second semiconductor section 60Z. A voltage VB, which is the sum of voltages VB1a and VB2a, is generated between the input terminal 61z and the output terminal 62z of the second semiconductor section 60Z.

[0138] The voltage VB exhibits a negative temperature dependence, decreasing as the temperature of diodes 60e and 60f increases and increasing as the temperature of diodes 60e and 60f decreases. The voltage VB also exhibits a positive stress dependence, increasing when tensile stress is applied to diodes 60e and 60f from the resin component 76 and decreasing when compressive stress is applied to diodes 60e and 60f from the resin component 76. Similar to the fourth embodiment described above, the resistor divider circuit 50 of this embodiment outputs from the output unit 52 a voltage obtained by multiplying voltage VZ-VA by a first weight and a voltage obtained by multiplying voltage VB by a second weight, which serves as a reference voltage Vref.

[0139] Therefore, similarly to the fourth embodiment described above, the temperature dependence of the Zener voltage VZ is canceled out by the temperature dependence of the voltage VA and the temperature dependence of the voltage VB. The stress dependence of the voltage VA and the stress dependence of the voltage VB cancel each other out, and the stress dependence of the Zener voltage VZ is canceled out by the stress dependence of the voltage VA. Through the above, a reference voltage output circuit 10 that suppresses changes in the reference voltage caused by temperature variations and changes in the reference voltage caused by stress variations can be provided.

[0140] (Eighth Embodiment) In the first embodiment described above, an example was described in which an NPN type transistor was used as a transistor 40 disposed between the current source 20 and the resistor divider circuit 50 in the reference voltage output circuit 10. However, instead, this eighth embodiment will be described with reference to FIG11 in which a PNP type transistor 40A is disposed between the current source 20 and the resistor divider circuit 50 in the reference voltage output circuit 10.

[0141] Figure 11 is a circuit diagram showing the circuit structure of the reference voltage output circuit 10 of this embodiment. In Figure 11, the same symbols as in Figure 1 denote the same parts, and their descriptions are omitted. As shown in Figure 11, the reference voltage output circuit 10 of this embodiment includes a transistor 40A instead of a transistor 40 as the first semiconductor unit. The transistor 40A includes a P-type semiconductor disposed between the current source 20 and the resistor divider circuit 50, an N-type semiconductor disposed between the P-type semiconductor and the resistor divider circuit 50, and a P-type semiconductor disposed between the N-type semiconductor and the resistor divider circuit 50.

[0142] Furthermore, for ease of explanation, the two P-type semiconductors constituting transistor 40A will be described below. The P-type semiconductor disposed between the current source 20 and the N-type semiconductor is designated as the positive-side P-type semiconductor, and the P-type semiconductor disposed between the N-type semiconductor and the resistor divider circuit 50 is designated as the negative-side P-type semiconductor. The positive-side P-type semiconductor is connected to the emitter terminal 41g. The N-type semiconductor is connected to the base terminal 43g. The positive-side P-type semiconductor is the first P-type semiconductor that forms a first PN junction with the N-type semiconductor. The negative-side P-type semiconductor is connected to the collector terminal 42g. Furthermore, the structure of the reference voltage output circuit 10 in this embodiment, except for transistor 40A, is the same as that in the reference voltage output circuit 10 of the first embodiment. Next, the operation of the reference voltage output circuit 10 of this embodiment will be described with reference to FIGS. 1, 2, and 3.

[0143] First, current source 20, based on the power supply voltage between positive electrode 1 and negative electrode 2, causes the main current Ia to flow from positive electrode 1 to negative electrode 2. A branch current Ib of the main current Ia flows from current source 20 to negative electrode 2 through Zener diode 30. Accompanyingly, Zener diode 30 generates a Zener voltage VZ between current source 20 and negative electrode 2 due to the Zener effect. On the other hand, branch current Ic, excluding branch current Ib of the main current Ia, flows from current source 20 to negative electrode 2 through transistors 40A and 60 and resistors 50a and 50b.

[0144] The branch current Ic flows from the emitter terminal 41g of transistor 40A through the first PN junction to the N-type semiconductor. A portion of the branch current Ic, i.e., the base current, flows from the N-type semiconductor through the base terminal 43g, bypassing the negative-side P-type semiconductor, to the collector terminal 42g. Therefore, transistor 40A is turned on. Simultaneously, in transistor 40A, the remaining current in the branch current Ic, excluding the base current, flows through the N-type semiconductor and the negative-side P-type semiconductor to the collector terminal 42g. Therefore, the branch current Ic flows from the collector terminal 41g through the first PN junction to the emitter terminal 42g. Thus, a voltage VA caused by the first PN junction is generated between the collector terminal (i.e., the first input terminal) 41g and the emitter terminal 42g (i.e., the second output terminal).

[0145] Furthermore, the branch current Ic flows through transistor 60 in the same manner as in the first embodiment described above. Therefore, the branch current Ic flows from emitter terminal 61 through the second P-type semiconductor and collector terminal 62 to the negative electrode 2. Consequently, a second voltage, namely voltage VB, is generated between emitter terminal 61 and collector terminal 62 due to the second PN junction. Additionally, the resistor divider circuit 50, as shown in Equation 1 above, outputs a reference voltage Vref from the common connection terminal 51. This reference voltage is obtained by multiplying the voltage VZ-VA (obtained by reducing the Zener voltage VZ by an amount equivalent to voltage VA) by a first weight, and the voltage VB by a second weight.

[0146] The Zener voltage VZ exhibits the same temperature dependence as in the first embodiment described above. The voltage VA also exhibits the same temperature dependence as in the first embodiment described above. Therefore, voltage VZ-VA has a positive temperature dependence. Voltage VB exhibits the same temperature dependence as in the first embodiment described above. The Zener voltage VZ exhibits the same stress dependence as in the first embodiment described above. Voltage VA exhibits the same stress dependence as in the first embodiment described above. Voltage VB exhibits the same stress dependence as in the first embodiment described above. The stress coefficient of the reference voltage Vref, as shown in Equation 2 above, can be expressed by the stress coefficients of the Zener voltage VZ, VA, and VB.

[0147] Furthermore, in this embodiment, as described above, the resistor divider circuit 50 adds the voltage obtained by multiplying the voltage VZ-VA by a first weight and the voltage obtained by multiplying the voltage VB by a second weight, and uses the resulting voltage as the reference voltage Vref. Thus, the stress dependence of voltage VA and the stress dependence of voltage VB cancel each other out. Moreover, in this embodiment, by using a PNP type transistor as transistor 40A, the stress coefficient of voltage VA in this embodiment is smaller than the stress coefficient of voltage VA in the first embodiment described above.

[0148] According to the embodiment described above, the reference voltage output circuit 10 includes a current source 20, a Zener diode 30, transistors 40A and 60, and a resistor divider circuit 50. Transistors 40A and 60 are PNP type transistors. The resistor divider circuit 50 outputs a voltage obtained by multiplying voltage VZ-VA by a first weight and adding the voltage obtained by multiplying voltage VB by a second weight, which is used as the reference voltage Vref. Thus, the temperature dependence of the Zener voltage VZ is canceled out by the temperature dependence of voltage VA and voltage VB. Furthermore, the stress dependence of voltage VA and voltage VB is also canceled out. Therefore, compared to the reference voltage output circuit 10A in FIG3, the reference voltage output circuit 10 can suppress changes in the reference voltage Vref caused by stress variations. Through the above, a reference voltage output circuit 10 that suppresses changes in the reference voltage Vref caused by temperature variations and also suppresses changes in the reference voltage Vref caused by stress variations can be provided.

[0149] (Other Embodiments) (1) In the first embodiment described above, an example of a first semiconductor section consisting of one transistor 40 was described. However, the first semiconductor section may also consist of two or more transistors 40. Similarly, the second semiconductor section is not limited to the case where a single transistor 60 constitutes the second semiconductor section; it may also consist of two or more transistors 60.

[0150] (2) In the second embodiment described above, an example of using six resistor elements 50a to 50f to form a resistor voltage divider circuit 50 was described. However, instead, as long as three or more resistor elements are used, the number of resistor elements forming the resistor voltage divider circuit 50 is not limited to six.

[0151] (3) In the third embodiment described above, an example of a second semiconductor section consisting of a single Zener diode 60a was described. However, it is not limited to this, and the second semiconductor section may also consist of two or more Zener diodes 60a.

[0152] (4) In the fourth embodiment described above, an example was given of a second semiconductor section consisting of two diodes 60b and 60c connected in parallel. However, it is not limited to this; a second semiconductor section may also be consisting of three or more diodes connected in parallel. Similarly, a second semiconductor section may also be consisting of multiple Zener diodes connected in parallel. Similarly, a second semiconductor section may also be consisting of multiple transistors connected in parallel. Furthermore, a second semiconductor section may also be consisting of multiple semiconductor elements connected in parallel and multiple semiconductor elements connected in series. Here, a semiconductor element refers to any one of a BJT, a diode, or a Zener diode.

[0153] (5) In the fifth embodiment described above, an example was given in which two diodes 40a and 40b connected in parallel constitute the first semiconductor section. However, it is not limited to this; the first semiconductor section may also be constituted by three or more diodes connected in parallel. Similarly, the first semiconductor section may also be constituted by a plurality of Zener diodes connected in parallel. Similarly, the first semiconductor section may also be constituted by a plurality of transistors connected in parallel. Furthermore, the first semiconductor section may also be constituted by combining a plurality of semiconductor elements connected in parallel and a plurality of semiconductor elements connected in series. Here, semiconductor element refers to any one of BJT, diode, and Zener diode.

[0154] (6) In the sixth embodiment described above, an example was given in which the first semiconductor section is composed of two diodes 40c and 40d connected in series. However, it is not limited to this, and the first semiconductor section may also be composed of three or more diodes connected in series. Similarly, the first semiconductor section may also be composed of a plurality of Zener diodes connected in series. Similarly, the first semiconductor section may also be composed of a plurality of transistors connected in series.

[0155] (7) In the seventh embodiment described above, an example was given in which two diodes 60e and 60f connected in series constitute the second semiconductor section. However, it is not limited to this, and the second semiconductor section may also be constituted by three or more diodes connected in series. Similarly, the second semiconductor section may also be constituted by a plurality of Zener diodes connected in series. Similarly, the second semiconductor section may also be constituted by a plurality of transistors connected in series.

[0156] (8) In the first embodiment described above, an example was described in which a Zener voltage was generated between the current source 20 and the negative electrode 2 by placing a Zener diode 30 between the current source 20 and the negative electrode 2. However, it is also possible to generate a Zener voltage between the current source 20 and the negative electrode 2 by placing two or more Zener diodes 30 between the current source 20 and the negative electrode 2 instead. Similarly, in the second to seventh embodiments described above, a Zener voltage can also be generated between the current source 20 and the negative electrode 2 by placing two or more Zener diodes 30 between the current source 20 and the negative electrode 2.

[0157] (9) In the first embodiment described above, an example of using a resin component 76 made of an electrically insulating resin material was described. However, it is not limited to this, and the resin component 76 may also be made of a ceramic component. Similarly, in the second to seventh embodiments described above, the resin component 76 may also be made of a ceramic component. Furthermore, in the first to seventh embodiments described above, the resin component 76 may also be made of a material other than resin or ceramic.

[0158] (10) Furthermore, this disclosure is not limited to the above-described embodiments, but can be appropriately modified within the scope of the claims. Additionally, the above-described embodiments are not mutually exclusive and can be appropriately combined except in cases where they are clearly incompatible. Furthermore, it is undeniable that in the above-described embodiments, the elements constituting the embodiments are not necessarily essential, except where they are specifically stated to be necessary or are generally considered necessary. Furthermore, in the above-described embodiments, when referring to the number, value, quantity, range, etc., of the constituent elements of the embodiments, the number is not limited to that specific number, except where it is specifically stated to be necessary or is generally limited to that specific number. Furthermore, in the above-described embodiments, when referring to the shape, positional relationship, etc., of the constituent elements, the shape, positional relationship, etc., is not limited to that shape, positional relationship, etc., except where it is specifically stated or is generally limited to that specific shape, positional relationship, etc.

Claims

1. A reference voltage output circuit, comprising: a current source disposed between a positive electrode and a negative electrode of a DC power supply, wherein a main current, which is a constant DC current, flows from the positive electrode to the negative electrode based on the power supply voltage between the positive electrode and the negative electrode; A Zener diode is disposed between the current source and the negative electrode, through which a first branch current, which is a part of the main current, flows, thereby generating a Zener voltage caused by the Zener effect between the current source and the negative electrode; a first semiconductor portion has: a first input terminal disposed between the current source and the negative electrode; and a first output terminal disposed between the first input terminal and the negative electrode; A first P-type semiconductor is disposed between the first input terminal and the first output terminal; The system includes a first N-type semiconductor disposed between the first P-type semiconductor and the first output terminal, and in contact with the first P-type semiconductor to form a first PN junction. A second branch current, other than the first branch current, flows from the first input terminal through the first PN junction to the first output terminal, thereby generating a first voltage caused by the first PN junction between the first input terminal and the first output terminal. The second semiconductor section includes: a second input terminal disposed between the first semiconductor section and the negative electrode; a second output terminal disposed between the second input terminal and the negative electrode; and a second P-type semiconductor disposed between the second input terminal and the second output terminal. And a second N-type semiconductor, disposed between the second P-type semiconductor and the second output terminal, and in contact with the second P-type semiconductor to form a second PN junction, wherein the second branch current flows from the second input terminal through the second PN junction to the second output terminal, thereby generating a second voltage caused by the second PN junction between the second input terminal and the second output terminal; A reference voltage generation unit is disposed between the first semiconductor portion and the second semiconductor portion, and outputs a reference voltage. The Zener diode, the first semiconductor portion, and the second semiconductor portion are configured to be covered by a packaged component. The Zener voltage has a temperature dependence that varies with the temperature of the Zener diode. The first voltage has a temperature dependence that varies with the temperature of the first semiconductor portion and a stress dependence that varies with the stress applied to the first semiconductor portion from the packaged component. The second voltage has a temperature dependence that varies with the temperature of the second semiconductor portion and a stress dependence that varies with the stress applied to the second semiconductor portion from the packaged component. When a voltage obtained by reducing the Zener voltage by an amount equivalent to the first voltage is set as a third voltage, the reference voltage generation unit outputs a voltage obtained by adding the third voltage multiplied by a first weight to the second voltage multiplied by a second weight as the reference voltage, such that the temperature dependence of the Zener voltage is canceled out by the temperature dependence of the first voltage and the temperature dependence of the second voltage, and the stress dependence of the first voltage is canceled out by the stress dependence of the second voltage.

2. A reference voltage output circuit, comprising: a current source disposed between the positive and negative electrodes of a DC power supply, wherein a main current, as a constant DC current, flows from the positive electrode to the negative electrode based on the power supply voltage between the positive and negative electrodes; A Zener diode is disposed between the current source and the negative electrode, through which a first branch current, which is a part of the main current, flows, thereby generating a Zener voltage caused by the Zener effect between the current source and the negative electrode; a first semiconductor portion has: a first input terminal disposed between the current source and the negative electrode; and a first output terminal disposed between the first input terminal and the negative electrode; A first P-type semiconductor is disposed between the first input terminal and the first output terminal; The system includes a first N-type semiconductor disposed between the first P-type semiconductor and the first output terminal, and in contact with the first P-type semiconductor to form a first PN junction. A second branch current, other than the first branch current, flows from the first input terminal through the first PN junction to the first output terminal, thereby generating a first voltage caused by the first PN junction between the first input terminal and the first output terminal. The second semiconductor section includes: a second input terminal disposed between the first semiconductor section and the negative electrode; a second output terminal disposed between the second input terminal and the negative electrode; and a second P-type semiconductor disposed between the second input terminal and the second output terminal. And a second N-type semiconductor, disposed between the second P-type semiconductor and the second output terminal, and in contact with the second P-type semiconductor to form a second PN junction, wherein the second branch current flows from the second input terminal through the second PN junction to the second output terminal, thereby generating a second voltage caused by the second PN junction between the second input terminal and the second output terminal; A reference voltage generation unit is disposed between the first semiconductor portion and the second semiconductor portion to output a reference voltage. The Zener diode, the first semiconductor portion, and the second semiconductor portion are configured to be covered by a packaged component. The Zener voltage has a temperature dependence that the Zener voltage changes with the temperature of the Zener diode, and a stress dependence that the Zener voltage changes with the stress applied to the Zener diode from the packaged component. The first voltage has a temperature dependence that the first voltage changes with the temperature of the first semiconductor portion, and a stress dependence that the first voltage changes with the stress applied to the first semiconductor portion from the packaged component. The second voltage has a temperature dependence that the second voltage changes with the temperature of the second semiconductor portion. And the second voltage varies according to the stress dependence of the stress applied from the package component to the second semiconductor portion. When the voltage obtained after the Zener voltage is reduced by an amount equivalent to the first voltage is set as the third voltage, the reference voltage generation unit outputs a voltage obtained by adding the third voltage multiplied by a first weight to the voltage obtained by multiplying the second voltage by a second weight, as the reference voltage, such that the temperature dependence of the Zener voltage is canceled out by the temperature dependence of the first voltage and the temperature dependence of the second voltage, and the stress dependence of the first voltage is canceled out by the stress dependence of the second voltage, and the stress dependence of the Zener voltage is canceled out by the stress dependence of the first voltage.

3. The reference voltage output circuit according to claim 1 or 2, wherein the first semiconductor section comprises any one of a bipolar junction transistor, a diode, and a Zener diode.

4. The reference voltage output circuit according to claim 3, wherein the first semiconductor section comprises a plurality of said semiconductor elements connected in series between the current source and the reference voltage generation section.

5. The reference voltage output circuit according to claim 3, wherein the first semiconductor section comprises a plurality of said semiconductor elements connected in parallel between the current source and the reference voltage generating section.

6. The reference voltage output circuit according to claim 3, wherein the bipolar junction transistor is diode-connected by connecting its base terminal to the collector terminal, which serves as the first input terminal.

7. The reference voltage output circuit according to claim 3, wherein the first input terminal of the diode is an anode terminal and the first output terminal of the diode is a cathode terminal.

8. In the reference voltage output circuit according to claim 3, the first input terminal of the Zener diode is an anode terminal, and the first output terminal of the Zener diode is a cathode terminal.

9. The reference voltage output circuit according to claim 1 or 2, wherein the second semiconductor section comprises any one of a bipolar junction transistor, a diode, and a Zener diode.

10. The reference voltage output circuit according to claim 9, wherein the second semiconductor section comprises a plurality of said semiconductor elements connected in series between the reference voltage generating section and the negative electrode.

11. The reference voltage output circuit according to claim 9, wherein the second semiconductor section comprises a plurality of said semiconductor elements connected in parallel between the reference voltage generating section and the negative electrode.

12. The reference voltage output circuit according to claim 9, wherein the bipolar junction transistor is diode-connected by connecting its base terminal to the collector terminal, which serves as the second input terminal.

13. The reference voltage output circuit according to claim 9, wherein the second input terminal of the diode is an anode terminal and the second output terminal of the diode is a cathode terminal.

14. The reference voltage output circuit according to claim 9, wherein the second input terminal of the Zener diode is an anode terminal, and the second output terminal of the Zener diode is a cathode terminal.

15. The reference voltage output circuit according to claim 1 or 2, wherein the reference voltage generating unit has a plurality of resistive elements connected in series between the first semiconductor unit and the second semiconductor unit, the reference voltage generating unit sets the voltage obtained by dividing the third voltage through the plurality of resistive elements as the voltage obtained by multiplying the third voltage by the first weight, and sets the voltage obtained by dividing the second voltage through the plurality of resistive elements as the voltage obtained by multiplying the second voltage by the second weight.

16. The reference voltage output circuit according to claim 15, wherein the plurality of resistive elements constitute a plurality of common connection terminals in which adjacent two resistive elements are commonly connected, and the reference voltage generating unit comprises: an output unit for outputting the reference voltage; and a plurality of switches for connecting or disconnecting the plurality of common connection terminals from the output unit, wherein by connecting any one of the plurality of common connection terminals to the output unit using a corresponding switch among the plurality of switches, the voltage between the any one common connection terminal and the negative electrode is output from the output unit as the reference voltage.

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