Voltage control circuit and voltage control method

Abstract

To reduce an increase in consumed current at a normal temperature and to suppress an increase in output voltage at a high temperature without remarkably increasing a circuit area.SOLUTION: A voltage control circuit controls an input voltage so as to be a predetermined output voltage corresponding to a reference voltage. The voltage control circuit includes: a voltage division circuit that divides an output voltage so as to output as a feedback voltage; a difference amplifier that amplifies a difference voltage between the reference voltage and the feedback voltage so as to output as a control voltage; an output transistor that controls an output current to be generated from an input voltage based on the control voltage; a first off transistor that generates a first leak current at a high temperature higher than a normal temperature; a current mirror circuit that includes a copy originator transistor which monitors and copies the first leak current, and a sink transistor which generates a sink current corresponding to the copied first leak current to cause the sink current to be sunk from the output current; and a resistor which increases a common control voltage of the current mirror circuit by resistance to increase the current sink performance of the sink transistor.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a voltage control circuit, such as a linear regulator, and a voltage control method for said voltage control circuit. [Background technology]

[0002] FIG. 8 is a circuit diagram showing a configuration of a regulator circuit 100 according to the conventional technique disclosed in Patent Document 1.

[0003] The disclosed series linear regulator circuit (hereinafter, referred to as the "regulator circuit") 100, as shown in FIG. (1) An error amplifier 114 that amplifies an error voltage between a reference voltage Vref of a reference voltage source formed in a semiconductor integrated circuit (hereinafter referred to as "IC") and a feedback voltage Vfb, and outputs an error amplified voltage Vg; (2) an output transistor 110 that controls an output load current IL based on an error amplified voltage Vg and supplies the output load current IL to a load 120 based on an input voltage Vin, thereby outputting an output voltage Vout; (3) a voltage dividing circuit consisting of voltage dividing resistors R101 and R102 that divides the output voltage Vout and feeds back the divided feedback voltage Vfb to the error amplifier 114; The present invention is configured to include the following components:

[0004] In the regulator circuit 100 configured as described above, when the output voltage Vout fluctuates due to the output load current IL or the input voltage Vin, the error voltage Vg between the reference voltage Vref and the feedback voltage Vfb is amplified, and negative feedback control is performed to keep the output voltage Vout constant.

[0005] Furthermore, the regulator circuit 100 can only step down the voltage, and is premised on a current flow from the power supply terminal 102 to the output terminal 104. Generally, the regulator circuit 100 does not control the output voltage Vout by drawing in (hereinafter referred to as "sink") an excessively high output voltage Vout into the regulator circuit 100. Therefore, when the output voltage Vout of the output terminal 104 becomes higher than the set output voltage, the output transistor 110 is turned off by negative feedback control. Here, the only components that reduce the output voltage Vout of the output terminal 104 are the externally connected load 120 and the internal voltage dividing resistors R101 and R102.

[0006] In this case, for example, when no load current IL flows externally and the ambient temperature at which the regulator circuit 100 is operated becomes high, if the leakage current from the output transistor 110 exceeds the current that can be sunk by the voltage dividing resistors, that is, if the voltage generated by the sum of the voltage dividing resistors (R101+R102)×the leakage current exceeds the set voltage, the output voltage Vout of the regulator circuit 100 will rise above the set voltage, and there is a risk that a voltage exceeding the withstand voltage of the connected load 120 will be applied.

[0007] In particular, when it is desired to reduce the current consumption of the IC, it is necessary to increase the absolute value of the voltage dividing resistor, which makes it easier for the output voltage to rise above the set voltage described above. As a conventional technique for solving such a problem, a technique is known in which the leakage current that becomes apparent at high temperatures is used to sink the leakage current of the output transistor 110 and suppress the rise in the output voltage (see Patent Document 1), as shown in FIG.

[0008] In the regulator circuit 100 of FIG. (1) a monitor MOS field effect transistor (hereinafter referred to as an "off transistor"; further, a MOS field effect transistor is referred to as an "MOS transistor") 112 whose gate and source are connected so as to be in an off state and which monitors the leakage current in the off characteristic of the output transistor 110 as a monitor current Im; (2) a current mirror circuit including a copy source MOS transistor (hereinafter referred to as the "copy source transistor") M1 that copies (copies) the monitor current Im and passes it, and a sink MOS transistor (hereinafter referred to as the "sink transistor") M2 that is connected to the output terminal 104 via a resistor R103 and sinks a sink current Ic (current corresponding to the copied current) that is a part of the output current IL; This configuration has the advantage that at an environmental temperature where no leakage current is generated from the output transistor 110, no leakage current is generated from the off transistor 112, and current consumption can be reduced. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Patent No. 5544105 Summary of the Invention [Problem to be solved by the invention]

[0010] In a circuit for preventing an increase in output voltage using a current generating circuit with the same leakage characteristics as the output transistor 110, an off transistor 112 is provided for generating the current, and a monitor current Im generated in the off transistor 112 is amplified by a current mirror circuit to generate a sink current Ic. For this reason, in the conventional technology of Fig. 8, it is necessary to set the size ratio between the output transistor 110 and the off transistor 112 so that the monitor current Im flowing in the off transistor 112 is 1 / 50 to 1 / 100 times the leakage current of the output transistor 110, which causes a problem of a significant increase in the circuit area.

[0011] Furthermore, depending on the size of the off transistor 112, the monitor current Im at room temperature may reach a level that affects the standby current of the IC, which may reduce the value of the regulator circuit 100 having low current consumption.

[0012] The object of the present invention is to provide a voltage control circuit and a voltage control method for said voltage control circuit, which can solve the above problems and reduce the increase in current consumption at room temperature while suppressing the increase in output voltage at high temperatures without significantly increasing the circuit area compared to the prior art. [Means for solving the problem]

[0013] A voltage control circuit according to one aspect of the present invention includes: A voltage control circuit that controls and outputs an input voltage so as to stabilize it to a predetermined output voltage corresponding to a reference voltage, a voltage divider circuit including a first resistor and a second resistor, which divides the output voltage and outputs the divided voltage as a feedback voltage; an error amplifier that amplifies a difference voltage between the reference voltage and the feedback voltage and outputs the amplified difference voltage as a control voltage; an output transistor that controls an output current generated from the input voltage based on the control voltage, and outputs the output current; a first off transistor that generates a first leakage current at a high temperature that is higher than a normal temperature; a current mirror circuit including a copy source transistor that monitors and copies the first leakage current, and a sink transistor that generates a sink current corresponding to the copied first leakage current, thereby sinking the sink current from the output current; a third resistor connected between the copy source transistor and ground, the third resistor increasing a common control voltage in the current mirror circuit by the third resistor, thereby increasing the current sinking capability of the sink transistor; Equipped with. Effect of the Invention

[0014] Therefore, according to the present invention, the amplification factor of the current mirror circuit that converts leakage current into sink current is amplified only at high temperatures, so that it is possible to reduce the increase in current consumption at room temperature and suppress the increase in output voltage at high temperatures without significantly increasing the circuit area compared to conventional technology. [Brief description of the drawings]

[0015] [Figure 1] 1 is a circuit diagram showing an example of the configuration of a voltage control circuit 1 according to a first embodiment. [Diagram 2] 1 is a circuit diagram showing an example of the configuration of a voltage control circuit 1A according to a first modified example of the first embodiment. [Diagram 3] 10 is a circuit diagram showing a configuration example of a voltage control circuit 1B according to a second modification of the first embodiment. FIG. [Figure 4] 10 is a circuit diagram showing an example of the configuration of a voltage control circuit 2 according to a second embodiment. FIG. [Diagram 5] 11 is a circuit diagram showing an example of the configuration of a voltage control circuit 2A according to a first modified example of the second embodiment. FIG. [Figure 6] 13 is a circuit diagram showing a configuration example of a voltage control circuit 2B according to a second modification of the second embodiment. FIG. [Figure 7] 4 is a graph showing an example of temperature characteristics of the resistance value of a resistor R11 used in the first and second embodiments. [Figure 8] FIG. 1 is a circuit diagram showing a configuration of a regulator circuit 100 according to the prior art. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, embodiments and modifications of the present invention will be described with reference to the drawings. Note that the same or similar components are denoted by the same reference numerals.

[0017] (Embodiment 1) Fig. 1 is a circuit diagram showing a configuration example of a voltage control circuit 1 according to a first embodiment. The voltage control circuit 1 in Fig. 1 is, for example, a series linear regulator, characterized in that a current mirror circuit 14 is connected to an output terminal and an off transistor Q2 that generates a leak current at a high temperature higher than room temperature, and a resistor R11 is inserted between the source of the copy source transistor Q11 of the current mirror circuit 14 and the ground. As a result, the current ratio per unit W / L of the transistors constituting the transistors Q11 and Q12, that is, the current I11 flowing through the copy source transistor Q11 of the current mirror circuit 14 and the current I12 flowing through the sink transistor Q12, is shifted from 1:1 to increase the current on the I12 side, thereby reducing an increase in current consumption at room temperature without significantly increasing the circuit area compared to the conventional technology, and suppressing an increase in output voltage at high temperatures.

[0018] In FIG. 1, the voltage control circuit 1 has a power supply terminal T1, an output terminal T2, and a ground terminal T3. The voltage control circuit 1 includes a reference voltage source 11, which is a reference voltage generating circuit, an error amplifier 12, an output transistor Q1, which is a power transistor, an off transistor Q2, whose gate and source are connected and turned off, a voltage dividing circuit 13, and a current mirror circuit 14. Here, the voltage dividing circuit 13 is configured as a series circuit of two resistors R1 and R2. The current mirror circuit 14 includes a diode-connected copy source transistor Q11 and a sink transistor Q12. The output transistor Q1 and the off transistor Q2 are configured as PMOS transistors, and the copy source transistor Q11 and the sink transistor Q12 are configured as NMOS transistors. The output terminal T2 is connected to, for example, a resistor element or a load 3 of an electronic device.

[0019] In FIG. 1, a power supply voltage VDD is input to an input terminal T1 as an input voltage Vin, and the input terminal T1 is grounded via the source and drain of an output transistor Q1, resistors R1 and R2 of a voltage dividing circuit 13, and a ground terminal T3. The input terminal T1 is also grounded via the source and drain of an off transistor Q2, the drain and source of a copy source transistor Q11, a resistor R11, and a ground terminal T3. A reference voltage source 11 generates a predetermined reference voltage Vref and outputs it to an inverting input terminal of an error amplifier 12. A divided voltage divided by resistors R1 and R2 of the voltage dividing circuit 13 is input to a non-inverting input terminal of the error amplifier 12 as a feedback voltage Vfb. The error amplifier 12 amplifies the difference voltage (Vfb-Vref) between the two input voltages, and applies the amplified voltage to the gate of the output transistor Q1 as a gate voltage Vg, which is a control voltage. The connection point between the drain of the output transistor Q1 and one end of the resistor R1 is connected to the output terminal T2, and is also grounded via the drain and source of the sink transistor Q12 of the current mirror circuit .

[0020] Here, the off transistor Q2 generates a leakage current at a high temperature (e.g., 30°C to 35°C or higher) higher than normal temperature, for example, 25°C, and passes the leakage current through the copy source transistor Q11 and resistor R11 of the current mirror circuit 14. In the current mirror circuit 14, when a current I11 flows through the copy source transistor Q11, a current proportional to the current I11, for example, I12=a×I11 (where a is a positive proportionality coefficient), flows through the sink transistor Q12. This current I12 is a current that compensates for (sinks) the leakage current generated in the output transistor Q1 at high temperatures (hereinafter referred to as "sink operation").

[0021] The back gate of the copy source transistor Q11 of the current mirror circuit 14 is connected to the source of the copy source transistor Q11.

[0022] In the voltage control circuit 1 configured as above, the error amplifier 12 generates and amplifies a difference voltage (Vfb-Vref) between the reference voltage Vref and the feedback voltage Vfb, which is a divided voltage obtained by dividing the output voltage Vout by the voltage divider circuit 13, in an imaginary short state, and applies the amplified difference voltage as a gate voltage Vg to the gate of the output transistor Q1 to control the current flowing through the output transistor Q1. As a result, the output voltage Vout is controlled by negative feedback so as to be stabilized to a predetermined voltage corresponding to the reference voltage source Vref. At this time, the voltage control circuit 1 is premised on supplying a load current in the direction of the ground voltage, and therefore does not have a mechanism for actively lowering the voltage of the output terminal T2 when the output voltage Vout rises.

[0023] Next, the current sink operation of the voltage control circuit 1 of FIG. 1 will be described below.

[0024] In the voltage control circuit 1 of Fig. 1, an off transistor Q2, a current mirror circuit 14, and a resistor R11 are provided as a circuit for sinking a leak current generated when the output transistor Q1 is at a high temperature. Here, the off transistor Q2 generates a leak current I11 when the temperature is high, and passes it to the copy source transistor Q11 of the current mirror circuit 14. At this time, the leak current I11 of the off transistor Q2 also passes through the resistor R11, and a drop voltage V11 expressed as the product of the leak current I11 and the resistance value of the resistor R11 occurs, and a voltage difference V11 occurs between the source voltage of the copy source transistor Q11 of the current mirror circuit 14 and the source voltage of the sink transistor Q12. Then, the common gate voltage (common control voltage) Vgcm of the current mirror circuit 14 increases compared to when the resistor R11 is not present, and the current sink capability of the sink transistor Q12 is increased compared to when the resistor R11 is not present.

[0025] As described above, in the first embodiment, by inserting the resistor R11, the mirror amplification amount of the current mirror circuit 14 increases only with the leakage current I11 of the off transistor Q2, so that if the resistor R11 is not present, the size (e.g., gate width) of the off transistor Q2 or the sink transistor Q12 must be increased to compensate for the sink capacity, but by simply adding the resistor R11, even if the size of the off transistor Q2 or the sink transistor Q12 is reduced, the sink current is high, so the increase in the output voltage Vout can be suppressed. Therefore, since the amplification factor of the current mirror circuit 14 that converts the leakage current into the sink current is amplified only at high temperatures, it is possible to suppress the increase in the output voltage at high temperatures while reducing the increase in the current consumption at normal temperatures without significantly increasing the circuit area compared to the conventional technology.

[0026] In the voltage control circuit 1 of FIG. 1, for example, it is preferable that the resistor R11 and the resistors constituting the voltage dividing circuit 13 are made of the same type of resistors (for example, resistors of the same type made of the same material and produced in the same manufacturing process). This configuration is also applicable to the following modified example of the first embodiment and the second embodiment and its modified example. For example, by using the same type of resistors, the absolute value variation of the resistance value within the same chip shows the same tendency in spite of the manufacturing variation of the resistors. That is, if the resistance value of the resistor R11 varies low, the resistance values ​​of the voltage dividing resistors R1 and R2 also decrease similarly. In this case, the drop voltage V11 described above decreases with the decrease in resistance, and the common gate voltage Vgcm also decreases accordingly, so that the sink capability of the sink transistor Q12 is reduced, but at this time, the resistance value of the current sink path formed by the voltage dividing resistors R1 and R2 decreases, and the current sink capability increases. Conversely, in a chip in which the resistance value of the resistor R11 varies high, the resistance values ​​of the voltage dividing resistors R1 and R2 also increase. In this case, the current sinking capability of the voltage dividing circuit 13 decreases, but the resistance value of the resistor R11 also increases, and as described above, the sinking capability of the sink transistor Q12 of the current mirror circuit 14 by the resistor R11 increases. In this way, by configuring the resistor R11 and the voltage dividing resistor 103 with the same type of resistor, a circuit configuration is obtained in which the total sinking capability can be complementarily compensated for the manufacturing variation of the resistors. Therefore, redundant design that takes into account the manufacturing variation of the resistance value is not necessary, and the circuit can be configured with a minimum number of resistors, making it possible to reduce the circuit area compared to when the same type of resistors are not used.

[0027] In the voltage control circuit 1 of FIG. 1, it is preferable to configure the resistor R11 with a resistor having a so-called positive temperature characteristic (an example is shown in FIG. 7), in which the resistance value becomes high at high temperatures higher than room temperature. This configuration is also applicable to the modified example of the first embodiment and the modified example of the second embodiment. As described above, when the resistance value of the resistor of the voltage dividing circuit 13 becomes high, the sink capability of the sink transistor Q12 of the current mirror circuit 14 becomes high. Therefore, by using a device having a high resistance value at high temperatures higher than room temperature for the resistor R11, the sink capability at high temperatures can be improved. This allows a circuit having the resistor R11 to be configured with a resistor having a smaller resistance value, so that the circuit area can be made smaller than when configured with a resistor without a positive temperature characteristic.

[0028] (Modification 1 of the first embodiment) Fig. 2 is a circuit diagram showing a configuration example of a voltage control circuit 1A according to Modification 1 of Embodiment 1. The voltage control circuit 1A in Fig. 2 differs from the voltage control circuit 1 in Fig. 1 in the following points. (1) The back gate of the copy source transistor Q11 of the current mirror circuit 14 is grounded via the ground terminal T3. The differences will be explained below.

[0029] In the voltage control circuit 1A configured as described above, when the back gate of the copy source transistor Q11 is grounded, the back bias effect of the copy source transistor Q11 causes the threshold voltage of the copy source transistor Q11 to become higher than the voltage drop V11 generated by the product of the resistance value of the resistor R11 and the current I11, and the common gate voltage Vgcm of the current mirror circuit 14 becomes higher than when the back gate of the copy source transistor Q11 is not grounded, and as a result, the current sink capability of the sink transistor Q12 is increased.

[0030] As described above, according to the first modification of the first embodiment, the operational effects of the first embodiment are obtained, and the current sink capability of the sink transistor Q12 can be increased due to the back bias effect of the copy source transistor Q11. The current sink capability of the first modification of the first embodiment can be increased more than that of the first embodiment.

[0031] (Modification 2 of the first embodiment) Fig. 3 is a circuit diagram showing a configuration example of a voltage control circuit 1B according to Modification 2 of Embodiment 1. The voltage control circuit 1B in Fig. 3 differs from the voltage control circuit 1A in Fig. 2 in the following points. (1) In place of the source transistor Q11 and the sink transistor Q12 of the current mirror circuit 14, a source transistor Q11A and a sink transistor Q12A having thicker gate oxide films than the source transistor Q11 and the sink transistor Q12, for example, are used in order to increase the withstand voltage of the gate terminals. The differences will be explained below.

[0032] In general, in order to increase the withstand voltage of the gate terminal of a MOS transistor, the back bias effect becomes more pronounced by thickening the gate oxide film. In the voltage control circuit 1B of FIG. 3, the sink current is amplified by the current mirror circuit 14 using the back bias effect of the copy source transistor Q11, and therefore the copy source transistor Q11A and the sink transistor Q12A, which are devices with thick gate oxide films, are used in the copy source transistor Q11 and the sink transistor Q12, making the back bias effect more pronounced. As a result, the increase in the circuit area of ​​the sink circuit can be reduced even in a high withstand voltage circuit.

[0033] As described above, according to the second modification of the first embodiment, the effects of the first modification of the first embodiment are achieved, and by thickening the gate oxide films of the copy source transistor Q11A and the sink transistor Q12A, the back bias effect becomes more pronounced, and the current sinking capability can be increased compared to the first modification of the first embodiment.

[0034] In addition, FIG. 3 shows an example configuration in which the source transistor Q11A and the sink transistor Q12A are MOS transistors with thick gate oxide films. However, even if only the source transistor Q11A has a thick gate oxide film, the effect of increasing the sink capability due to the back bias effect can be obtained.

[0035] (Embodiment 2) Fig. 4 is a circuit diagram showing an example of the configuration of a voltage control circuit 2 according to embodiment 2. The voltage control circuit 2 in Fig. 4 differs from the voltage control circuit 1 in Fig. 1 in the following points. (1) In the voltage control circuit 1 of FIG. 1, an off transistor Q3, which has a threshold voltage lower than the threshold voltages of the output transistor Q1 and the off transistor Q2 and generates a leakage current at high temperatures higher than room temperature, like the off transistor Q2, is connected in parallel to the series circuit of the off transistor Q2 and the copy source transistor Q11. The differences will be explained below.

[0036] 4, the input terminal T1 is connected to the gate and source of the off transistor Q3, and the drain is grounded via a resistor R11 and a ground terminal T3. The off transistor Q3 is a device having a lower threshold voltage than the threshold voltages of the output transistor Q1 and the off transistor Q2, and generates a leakage current I13 larger than the leakage current of the off transistor Q2. By injecting this leakage current I13 into the resistor R11, as described in the first embodiment, the drop voltage V11 generated by the resistor R11 and the leakage current can be increased, and the sink capability of the sink transistor Q12 of the current mirror circuit 14 can be amplified.

[0037] It is also possible to inject the leakage current I13 of the off transistor Q3 into the drain of the copy source transistor Q11 of the current mirror circuit 14. However, in this case, the sink current of the copy source transistor Q11 would begin to increase at a temperature lower than the temperature at which conventional leakage currents become a problem, increasing the current consumption of the IC. Therefore, the leakage current I13 of the off transistor Q3, which has a lower threshold voltage and is therefore more prone to leakage, is not injected into the current mirror circuit 14.

[0038] As described above, according to the second embodiment, the sink current I12 of the sink transistor Q12 of the current mirror circuit 14 occurs only at the temperature where only the leakage current I1 of the output transistor Q1 becomes apparent, and the sink capability of the sink transistor Q12 can be increased by using the leakage characteristic of the off transistor Q3, compared to the case where only the leakage current I11 of the off transistor Q2 occurs. Therefore, even if the off transistor Q3 is configured with a smaller circuit area than the off transistor Q2, the leakage current I13 occurs, so that the sink transistor Q12 can have a sufficient sink capability with an even smaller circuit area, and the rise in the output voltage can be suppressed, compared to the first embodiment configured with only the off transistor Q2.

[0039] (Modification 1 of the second embodiment) Fig. 5 is a circuit diagram showing a configuration example of a voltage control circuit 2A according to Modification 1 of Embodiment 2. The voltage control circuit 2A in Fig. 5 differs from the voltage control circuit 2 in Fig. 4 in the following points. (1) The back gate of the copy source transistor Q11 of the current mirror circuit 14 is grounded via the ground terminal T3. The differences will be explained below.

[0040] In the voltage control circuit 2A configured as described above, when the back gate of the copy source transistor Q11 is grounded, the back bias effect of the copy source transistor Q11 causes the common gate voltage Vgcm of the current mirror circuit 14 to rise above the voltage drop V11 generated by the product of the resistance value of the resistor R11 and the current I11, as compared to when the back gate of the copy source transistor Q11 is not grounded, and as a result, the current sink capability of the sink transistor Q12 is increased.

[0041] As described above, according to the first modification of the second embodiment, the effects of the second embodiment are achieved, and the current sink capability of the sink transistor Q12 can be increased due to the back bias effect of the copy source transistor Q11. The current sink capability of the second modification of the second embodiment can be increased more than that of the second embodiment.

[0042] (Modification 2 of the second embodiment) Fig. 6 is a circuit diagram showing a configuration example of a voltage control circuit 2B according to Modification 2 of Embodiment 2. The voltage control circuit 2B in Fig. 6 differs from the voltage control circuit 2A in Fig. 5 in the following points. (1) In place of the source transistor Q11 and sink transistor Q12 of the current mirror circuit 14, for example, a source transistor Q11A and a sink transistor Q12A having thicker gate oxide films than the source transistor Q11 and the sink transistor Q12 are used in order to increase the withstand voltage of the gate terminals. The differences will be explained below.

[0043] In general, in order to increase the withstand voltage of the gate terminal of a MOS transistor, the back bias effect becomes more pronounced by thickening the gate oxide film. In the voltage control circuit 2A of FIG. 5, the sink current is amplified by the current mirror circuit 14 using the back bias effect of the copy source transistor Q11, so by using the copy source transistor Q11A, which is a device with a thick gate oxide film, in the copy source transistor Q11, the back bias effect becomes more pronounced. As a result, the increase in the circuit area of ​​the sink circuit can be reduced even in a high-withstand voltage circuit. In addition, by using a device with the same oxide film thickness as Q11A in the sink transistor Q12A, the error in the threshold voltages of Q12A and Q11A can be minimized, which is preferable.

[0044] As described above, according to the second modification of the second embodiment, the effects of the first modification of the second embodiment are achieved, and in addition, by thickening the gate oxide films of the copy source transistor Q11A and the sink transistor Q12A, the back bias effect becomes more pronounced, and the current sinking capability can be increased compared to the first modification of the second embodiment.

[0045] Even if only the source transistor Q11A has a thick gate oxide film, the back bias effect can still increase the sink capacity. [Industrial Applicability]

[0046] As described above in detail, according to the present invention, since the amplification factor of the current mirror circuit that converts the leakage current into the sink current is amplified only at high temperatures, it is possible to reduce the increase in current consumption at normal temperatures and suppress the increase in output voltage at high temperatures without significantly increasing the circuit area compared to the conventional technology. In addition, since the effect is more pronounced in products that use devices with high-voltage oxide films, it is also suitable for application to high-voltage products. [Explanation of symbols]

[0047] 1, 1A~1B, 2, 2A~2B Voltage control circuit 3. Load 11 Reference voltage source 12 Error Amplifier 13 Voltage divider circuit 14 Current mirror circuit Q1 Output transistor Q2, Q3 off transistor Q11, Q11A Copy source transistor Q12, Q12A Sink transistor R1~R11 Resistors T1 power terminal T2 output terminal T3 ground terminal

Claims

1. A voltage control circuit that controls and outputs an input voltage so as to stabilize it to a predetermined output voltage corresponding to a reference voltage, a voltage divider circuit including a first resistor and a second resistor, which divides the output voltage and outputs the divided voltage as a feedback voltage; an error amplifier that amplifies a difference voltage between the reference voltage and the feedback voltage and outputs the amplified difference voltage as a control voltage; an output transistor that controls an output current generated from the input voltage based on the control voltage, and outputs the output current; a first off transistor generating a first leakage current at a high temperature higher than a normal temperature; a current mirror circuit including a copy source transistor that monitors and copies the first leakage current, and a first sink transistor that generates a sink current corresponding to the copied first leakage current, thereby sinking the sink current from the output current; a third resistor connected between the copy source transistor and ground, the third resistor increasing a common control voltage in the current mirror circuit by the third resistor, thereby increasing the current sinking capability of the first sink transistor; A voltage control circuit comprising:

2. a second off transistor having a threshold voltage lower than a threshold voltage of the first off transistor, generating a second leakage current at a high temperature higher than a room temperature, and causing the second leakage current to flow to ground via the third resistor; 2. The voltage control circuit of claim 1.

3. 3. The voltage control circuit according to claim 1, wherein the second resistor and the third resistor are made of the same type of resistor.

4. 3. The voltage control circuit according to claim 1, wherein the third resistor is configured so that its resistance value has a positive temperature characteristic.

5. 3. The voltage control circuit according to claim 1, wherein a back gate of the copy source transistor is grounded, and a current sink capability of the sink transistor is increased by a back bias effect.

6. 6. The voltage control circuit according to claim 5, wherein the gate of the copy source transistor is made to withstand high voltage to thereby increase the back bias effect and increase the current sink capability of the sink transistor.

7. A voltage control method for a voltage control circuit that controls and stabilizes an input voltage to a predetermined output voltage corresponding to a reference voltage, comprising the steps of: The voltage control circuit includes: a voltage divider circuit including a first resistor and a second resistor, which divides the output voltage and outputs the divided voltage as a feedback voltage; an error amplifier that amplifies a difference voltage between the reference voltage and the feedback voltage and outputs the amplified difference voltage as a control voltage; an output transistor that controls an output current generated from the input voltage based on the control voltage, and outputs the output current; a first off transistor generating a first leakage current at a high temperature higher than a normal temperature; a current mirror circuit including a copy source transistor that monitors and copies the first leakage current, and a sink transistor that generates a sink current corresponding to the copied first leakage current, thereby sinking the sink current from the output current; The voltage control method includes: a third resistor connected between the copy source transistor and ground increases a common control voltage in the current mirror circuit by the third resistor, thereby increasing a current sink capability of the sink transistor. Voltage control method.

8. a second off transistor having a threshold voltage lower than a threshold voltage of the first off transistor generates a second leakage current at a high temperature higher than a normal temperature, and causes the second leakage current to flow to ground via the third resistor. The voltage control method according to claim 7.

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