Switching control voltage generator, band-gap reference generator and switching voltage generation method thereof

Abstract

A semiconductor device including a bandgap reference generator that generates a reference voltage; a switch control voltage generator that generates a first reference current based on the reference voltage, and generates an adaptive switch level voltage by distributing the first reference current to a first path including a first resistor and a second path including a second resistor; the second path comprises a second resistor and a first bipolar junction transistor which are connected in series; and a switch controller that generates a switch control signal for controlling a switch included in the bandgap reference generator based on the adaptive switch level voltage. The adaptive switching level voltage has a slope with respect to temperature greater than a slope with respect to temperature of a base-emitter voltage of the first bipolar junction transistor.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the priority of Korean Patent Application No. 10-2023-0090436 filed in the Korean Intellectual Property Office on July 12, 2023, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] Embodiments of the present disclosure relate to semiconductor devices, and more particularly, to a switching control voltage generator, a bandgap reference generator, and a switching voltage generating method thereof. Background Art

[0004] Due to the development of fine processes, it has become possible to integrate more devices per unit area in semiconductor chips. The performance improvement of semiconductor chips is also accelerating. Due to the improved performance and reduced line width, the heat generated from semiconductor devices has a great influence on the stability of the devices. Therefore, generating a reference voltage that is stable with respect to temperature has become a means for ensuring the performance or reliability of semiconductor devices.

[0005] Bandgap reference BGR circuits are usually used to generate reference voltages for semiconductor devices. With the development of advanced processes, process issues such as bipolar junction transistor BJT dispersion, leakage current, and contact resistance have an increasing impact on the accuracy of BGR circuits. In order to optimize the accuracy of BGR circuits in such environments, techniques such as trimming or chopping are applied. Trimming or chopping of BGR circuits is performed using the on / off action of a switch connected to the BJT. However, controlling switches in low-voltage environments has become an increasingly difficult problem due to the miniaturization of processes. Summary of the invention

[0006] Example embodiments of the inventive concept provide a switching voltage generating circuit and a voltage generating method capable of improving the switching accuracy of a switch controlling a bandgap reference BGR circuit even under miniaturization and low voltage conditions. Example embodiments of the inventive concept also provide a bandgap reference generator capable of improving the reliability of a reference voltage based on high switching accuracy.

[0007] An example embodiment of the inventive concept provides a semiconductor device including: a bandgap reference generator that generates a reference voltage; a switch control voltage generator that generates a first reference current based on the reference voltage and generates an adaptive switch level voltage by distributing the first reference current to a first path and a second path, the first path including a first resistor, and the second path including a second resistor and a first bipolar junction transistor connected in series; and a switch controller that generates a switch control signal for controlling a switch included in the bandgap reference generator based on the adaptive switch level voltage. The adaptive switch level voltage has a slope with respect to temperature greater than a slope with respect to temperature of a base-emitter voltage of the first bipolar junction transistor.

[0008] An example embodiment of the inventive concept also provides a switch control voltage generator, comprising: a first current source connected to a power supply voltage, the first current source transmitting a first reference current having a constant level relative to temperature to a first node; a first resistor connected between the first node and ground; a second resistor having one end connected to the first node; and a diode-connected bipolar junction transistor connected between the other end of the second resistor and ground. The first resistor, the second resistor, and the diode-connected bipolar junction transistor generate an adaptive switch level voltage at the first node, the slope and magnitude of the offset of the adaptive switch level control voltage relative to temperature being adjustable based on the resistance of the first resistor and the second resistor.

[0009] An example embodiment of the present inventive concept also provides a method for generating a switching voltage for switching of a bandgap reference generator, the method comprising: generating a reference current based on a reference voltage provided from the bandgap reference generator; generating an adaptive switching level voltage by distributing the reference current to a first path and a second path, the first path comprising a first resistor, and the second path comprising a second resistor connected in series and a diode-connected bipolar junction transistor; generating a switching control signal for controlling a switching element of the bandgap reference generator based on the adaptive switching level voltage; and applying the switching control signal to the switching element of the bandgap reference generator. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The above and other objects and features of the present disclosure will become apparent in view of the description of example embodiments of the present disclosure with reference to the accompanying drawings.

[0011] Figure 1 is a block diagram illustrating a semiconductor device including a switching-controlled voltage generator according to some example embodiments of the inventive concept.

[0012] Figure 2 It is shown Figure 1 A circuit diagram of an example of a switch-controlled voltage generator.

[0013] Figure 3A , Figure 3B , Figure 3C and Figure 3D It is shown Figure 2 A graph of the temperature characteristics of the control voltage generator.

[0014] Figure 4 is a circuit diagram illustrating a bandgap reference generator using a switch-controlled voltage generator according to some example embodiments of the inventive concept.

[0015] Figure 5A and Figure 5B are respectively shown according to some example embodiments Figure 4 Circuit diagram of the trimming circuit and the chopping circuit.

[0016] Figure 6 is a diagram showing some example embodiments of the present invention. Figure 1 Circuit diagram of a switch controlled voltage generator.

[0017] Figure 7 It shows that according to Figure 6 Circuit diagrams of bandgap reference generators using switch-controlled voltage generators of some example embodiments of the inventive concepts.

[0018] Figure 8 is a flow chart illustrating a method of controlling a low voltage switch for trimming or chopping of a bandgap reference generator according to some example embodiments of the inventive concept.

[0019] Fig. 9 is a circuit diagram illustrating a bandgap reference generator using a switch-controlled voltage generator according to some example embodiments of the inventive concept.

[0020] Fig.10 is a circuit diagram illustrating a bandgap reference generator using a switch-controlled voltage generator according to some example embodiments of the inventive concept. DETAILED DESCRIPTION

[0021] It should be understood that both the foregoing general description and the following detailed description correspond to example embodiments.Where possible, the same reference numerals and characters are used in the specification and drawings to refer to the same or similar parts.

[0022] When the terms "approximately" or "substantially" are used in conjunction with a numerical value in this specification, it is intended that the associated numerical value includes a manufacturing or operating tolerance (e.g., ±10%) around the numerical value. In addition, when the words "approximately" and "substantially" are used in conjunction with a geometric shape, it is intended that the precision of the geometric shape is not required, but rather the tolerance of the shape is within the scope of the present disclosure. In addition, regardless of whether a numerical value or shape is modified as "approximately" or "substantially", it should be understood that these values ​​and shapes should be interpreted as including a manufacturing or operating tolerance (e.g., ±10%) around the numerical value or shape. When a range is specified, the range includes all values ​​therebetween, such as increments of 0.1%.

[0023] In addition, for example, "at least one of A, B, and C" and similar language (e.g., "at least one selected from the group consisting of A, B, and C") may be interpreted as A only, B only, C only, or any combination of two or more of A, B, and C, such as ABC, AB, BC, and AC.

[0024] In the following, the advantages of the inventive concept will be explained using a bandgap reference BGR generator using a bipolar junction transistor BJT as an example. A switch of a trimming circuit or a chopper circuit for increasing the accuracy of a bandgap reference generator will be described using a PMOS transistor as an example. However, based on the teachings herein, those skilled in the art will readily understand other advantages and capabilities of the inventive concept. The inventive concept may be implemented or applied through other embodiments. The detailed description may be modified or changed according to viewpoints and applications without significantly departing from the scope, spirit, and other purposes of the inventive concept.

[0025] Figure 1 is a block diagram illustrating a semiconductor device including a switch-controlled voltage generator according to some example embodiments of the inventive concept. Figure 1 , the semiconductor device 100 may include a switch control voltage generator 110 , a switch controller 130 , and a bandgap reference generator 150 .

[0026] The switch control voltage generator 110 generates an adaptive switch level voltage VASL for ensuring or improving the reliability of the bandgap reference generator 150. For example, the switch control voltage generator 110 generates an adaptive switch level voltage VASL for trimming or chopping the bandgap reference generator 150. The trimming or chopping of the bandgap reference generator 150 is performed by switching the low voltage transistor. Therefore, the switch control voltage provided to the bandgap reference generator 150 must be able to reduce the leakage current of the low voltage transistor at a specific temperature. The switch control voltage must be able to provide the conduction reliability of the low voltage transistor at other specific temperatures. To this end, the switch control voltage generator 110 generates a voltage close to the base-emitter voltage VBE of a bipolar junction transistor (e.g., BJT) at a low temperature (e.g., T0), and generates a voltage higher than the base-emitter voltage VBE at a high temperature (e.g., T1). That is, the switch control voltage generator 110 can generate an adaptive switch level voltage VASL according to the temperature.

[0027] According to the characteristics of the switch control voltage generator 110, such as Figure 1 As shown, the adaptive switch level voltage VASL is lower than the withstand voltage Vd of the switching transistor and is close to the base-emitter voltage VBE at a low temperature (T0, for example, about -55°C). On the other hand, at a high temperature (T1, for example, about 150°C), the adaptive switch level voltage VASL can be generated at a level V2 higher than the level V1 of the base-emitter voltage VBE. Therefore, if the adaptive switch level voltage VASL is used, it is higher than the threshold voltage of the low voltage switch implemented using the PMOS transistor even at a low temperature (T0), thereby limiting or preventing the turn-off failure problem. Even at a high temperature (T1), when the adaptive switch level voltage VASL is applied, the low voltage switch implemented using the PMOS transistor can be cut off without leakage current.

[0028] The switch controller 130 controls the switching transistor of the bandgap reference generator 150 using the adaptive switch level voltage VASL. For example, the switch controller 130 generates a switch control voltage VSW of a low voltage transistor for trimming or chopping of the bandgap reference generator 150. The switch controller 130 generates a switch control voltage VSW for controlling the trimming circuit 152 of the bandgap reference generator 150 using the adaptive switch level voltage VASL. That is, the switch controller 130 uses the switch control voltage VSW generated based on the adaptive switch level voltage VASL to turn on or off the low voltage transistor that determines the size of the resistance in the trimming circuit 152. The switch controller 130 can control the chopping circuit 154 of the bandgap reference generator 150 using the switch control voltage VSW generated based on the adaptive switch level voltage VASL. That is, the switch controller 130 can perform switching of the switch of the chopping circuit 154 based on the adaptive switch level voltage VASL.

[0029] The bandgap reference generator 150 may be a circuit that generates a bandgap reference voltage VBGR. The bandgap reference voltage VBGR may be used as a reference voltage for various functional blocks of the semiconductor device 100. The bandgap reference voltage VBGR may be used as a reference voltage used in an analog circuit or a digital circuit. For example, the bandgap reference voltage VBGR may be provided as a reference voltage to an analog circuit such as a comparator.

[0030] When the reference voltage is different from the expected value at the time of design, the semiconductor device 100 may fail or output an incorrect data signal. In order to ensure the operational reliability of the semiconductor device 100, the bandgap reference generator 150 must be robust to external factors (e.g., temperature changes, noise, leakage current, etc.). That is, the bandgap reference generator 150 may need to generate a reference voltage that is insensitive to process-voltage-temperature PVT.

[0031] The bandgap reference generator 150 of the present inventive concept includes a trimming circuit 152 and a chopping circuit 154, which are switched by a switch control voltage VSW provided from a switch controller 130. The bandgap reference generator 150 can generate a highly accurate bandgap reference voltage VBGR using the trimming circuit 152 and the chopping circuit 154. The trimming circuit 152 trims the emitter current according to the switch control voltage VSW. In some example embodiments, since the switch control voltage VSW becomes higher than the base-emitter voltage VBE at a high temperature, a leakage current generated from a turned-off low voltage switch can be blocked. Therefore, the degradation of the distribution of the bandgap reference voltage VBGR caused by the leakage current of the switch transistor of the bandgap reference generator 150 can be improved.

[0032] The switch control voltage VSW may also be used in the chopper circuit 154 of the bandgap reference generator 150. The chopper circuit 154 is a circuit for eliminating offsets by cross-switching differential signals at input terminals or inside an amplifier (not shown). For example, the switch control voltage VSW of the present invention may be used to control a low voltage switch constituting the chopper circuit 154. In some example embodiments, even at a low temperature T0 where the voltage level is relatively low compared to a high temperature, a turn-off failure of the low voltage switch may be limited or prevented. Therefore, the offset elimination effect of the chopper circuit 154 switched using the switch control voltage VSW may be guaranteed. Therefore, the reliability of the bandgap reference generator 150 may be improved.

[0033] The semiconductor device 100 described above can control the switch of the bandgap reference generator 150 using the adaptive switch level voltage VASL generated by the switch control voltage generator 110. Therefore, the bandgap reference generator 150 that provides a highly reliable bandgap reference voltage VBGR can be implemented.

[0034] Figure 2 is a diagram showing some example embodiments Figure 1 The circuit diagram of the switch controlled voltage generator. Figure 2 According to some example embodiments, the switch control voltage generator 110a includes a current source 111, a bipolar junction transistor Q1, and first and second resistors R1 and R2. The switch control voltage generator 110a may generate an adaptive switch level voltage VASL using a base-emitter voltage VBE of the bipolar junction transistor Q1.

[0035] The first current I CTAT is supplied to the first resistor R1, and the second current I PTAT The current source 111 can maintain the reference current I even when the temperature changes. REF For example, the current source 111 may be a current source 112 which is a constant level of . Figure 1 ) generates a bandgap reference voltage VBGR to mirror the current.

[0036] The reference current I supplied by the current source 111 REF is branched into two current paths. That is, through the first path including the first resistor R1, the reference current I REF is branched into a first current I CTAT In addition, through the second path including the second resistor R1 and the bipolar junction transistor Q1, the reference current I REF Branched into the second current IPTAT.

[0037] When current is supplied, a base-emitter voltage VBE is formed in the diode-connected bipolar junction transistor Q1. The base-emitter voltage VBE of the bipolar junction transistor Q1 generally exhibits a complementary to absolute temperature (ComplementaryTo Absolute Temperature) CTAT characteristic, which decreases as the temperature increases. The adaptive switching level voltage VASL dominated by the influence of the base-emitter voltage VBE also has a characteristic of decreasing as the temperature increases.

[0038] When the adaptive switch level voltage VASL decreases as the temperature increases, the first current I flowing through the first resistor R1 CTAT On the other hand, the second current I flowing through the second resistor R2 PTAT With the reference current I REF Subtract the first current I CTAT Therefore, the second current I flowing through the second resistor R2 PTAT The second current I PTAT The voltage V formed on the second resistor R2 PTAT Will have a PTAT characteristic that is proportional to temperature.

[0039] The adaptive switch level voltage VASL is proportional to the base-emitter voltage VBE and the temperature voltage V formed at the second resistor R2. PTAT Since the base-emitter voltage VBE basically exhibits a temperature complementary CTAT characteristic, the adaptive switch level voltage VASL is proportional to the temperature voltage V PTAT However, by forming a temperature proportional voltage V in the second resistor R2 PTAT The temperature proportional characteristic of the base-emitter voltage VBE is added to the temperature complementary characteristic of the base-emitter voltage VBE, and the adaptive switching level voltage VASL appears in the form of an increased slope greater than the slope of the base-emitter voltage VBE. The adaptive switching level voltage VASL can be generated at a level lower than the withstand voltage of the switching transistor used for chopping or trimming. That is, the adaptive switching level voltage VASL is close to the base-emitter voltage VBE at low temperatures, but can be generated as a temperature complementary CTAT voltage that is a certain level higher than the base-emitter voltage VBE at high temperatures. The relationship between the adaptive switching level voltage VASL and the base-emitter voltage VBE will be described in more detail through the drawings described later.

[0040] A PNP type bipolar junction transistor Q1 has been described as an example embodiment for explaining the advantages of the inventive concept. However, the inventive concept is not limited to the disclosure herein, and various modifications are possible. That is, the bipolar junction transistor Q1 of the inventive concept has been described as a PNP type commonly used in CMOS semiconductor processes as an example, but it will be well understood that it can be an NPN type bipolar junction transistor.

[0041] The switch control voltage generator 110a according to some example embodiments of the above-described inventive concepts may generate an adaptive switch level voltage VASL having a slope with respect to temperature greater than a slope with respect to temperature of a base-emitter voltage VBE. This function may be implemented by a current source 111 that generates a reference current I of a constant magnitude regardless of temperature changes using a first resistor R1 and a second resistor R2. REF and current distribution.

[0042] Figure 3A , Figure 3B , Figure 3C and Figure 3D It is shown Figure 2 A graph of the temperature characteristics of the switching control voltage generator. Figure 3A The first current I is adjusted according to the size of the first resistor R1. CTAT changes. Figure 3B The second current I is shown according to the adjustment of the size (eg, resistance adjustment) of the first resistor R1. PTAT changes. Figure 3C FIG. 4 shows the change of the adaptive switch level voltage VASL adjusted according to the size of the first resistor R1. In addition, Figure 3D The variation of the slope of the adaptive switching level voltage VASL adjusted according to the size of the second resistor R2 is shown.

[0043] refer to Figure 3A , showing a first current I according to the magnitude (eg, resistance) of the first resistor R1 in the switch control voltage generator 110a. CTAT The reference current I that maintains a constant level relative to temperature changes REF is distributed to the current path formed by the first resistor R1 and the second resistor R2. The adaptive switching level voltage VASL based on the base-emitter voltage VBE of the bipolar junction transistor Q1 basically has a temperature-compensated CTAT characteristic. Therefore, the adaptive switching level voltage VASL having the temperature-compensated CTAT characteristic is formed at both ends of the first resistor R1. The first current I flowing through the first resistor R1 CTATThe amplitude of the first current I can be controlled by adjusting the amplitude of the first resistor R1. If the amplitude of the first resistor R1 increases, the first current I CTAT The slope of is constant, but the magnitude decreases over the entire temperature range. On the other hand, if the magnitude of the first resistor R1 decreases, the first current I CTAT The magnitude of the first current I will show an increasing magnitude characteristic, although the slope is constant over the entire temperature range. Increasing or decreasing the first current I over the entire temperature range CTAT The absolute amplitude characteristic is defined as the expression of increasing or decreasing offset. Therefore, it can be seen that by adjusting the size of the first resistor R1, the first current I CTAT The slope with respect to temperature is constant, but the offset can be adjusted.

[0044] refer to Figure 3B , showing the second current I according to the magnitude (eg, resistance) of the first resistor R1 of the switch control voltage generator 110a. PTAT The reference current I does not change level with respect to temperature changes. REF As the first current I CTAT is distributed to the first resistor R1 and as the second current I PTAT is distributed to the second resistor R2. Therefore, by REF Subtract the first current I CTAT To obtain the second current I PTAT This means that the second current I can also be controlled by adjusting the size of the first resistor R1 (eg, adjusting the resistance). PTAT If the magnitude of the first resistor R1 increases, the first current I CTAT The amplitude of the second current I PTAT On the other hand, when the magnitude of the first resistor R1 decreases, the first current I CTAT The amplitude of the second current I PTAT According to this mechanism, the second current I PTAT The second current I can be increased or decreased with the same slope in the whole temperature range according to the adjustment of the first resistor R1. That is, the second current I can be adjusted in the whole temperature range according to the adjustment of the first resistor R1. PTAT offset.

[0045] refer to Figure 3C, shows a change in the adaptive switch level voltage VASL according to the magnitude (e.g., resistance) of the first resistor R1 in the switch control voltage generator 110a. The adaptive switch level voltage VASL is also a voltage formed on the first resistor R1. Therefore, the adaptive switch level voltage VASL appears as a function of the first current I flowing through the first resistor R1. CTAT Therefore, the adaptive switching level voltage VASL can be similar to Figure 3A The first current I shown in CTAT For example, when the magnitude of the first resistor R1 increases, the first current I CTAT The magnitude of the adaptive switch level voltage VASL decreases. Therefore, according to the size (e.g., resistance) of the first resistor R1, the adaptive switch level voltage VASL shows a characteristic of only decreasing in size without changing in slope over the entire temperature range. On the other hand, when the first resistor R1 decreases, the level of the adaptive switch level voltage VASL increases over the entire temperature range without changing in slope according to the first current I CTAT changes with the increase of.

[0046] However, the adaptive switching level voltage VASL must be equal to or higher than the base-emitter voltage VBE at the low temperature T0. The adaptive switching level voltage VASL of the switching transistor of the chopper circuit 154 must be higher than the bipolar junction transistor (Q2, see the following description) of the bandgap reference generator 150. Figure 4 ) has a high base-emitter voltage VBE. This is because the turn-off failure of the switching transistor of the chopper circuit 154 can be limited and / or prevented. At high temperature T1, the adaptive switching level voltage VASL must be at the bipolar junction transistor (Q2, see the following description) of the bandgap reference generator 150. Figure 4 ) has a sufficient margin on the base-emitter voltage VBE. This is to block leakage current that may occur in the switch transistor of the trimming circuit 152. Therefore, it can be seen that the difference between the adaptive switching level voltage VASL and the base-emitter voltage VBE can be adjusted by adjusting the size of the first resistor R1.

[0047] Figure 3D1 shows a change in the adaptive switch level voltage VASL according to the magnitude (e.g., resistance) of the second resistor R2 in the switch control voltage generator 110a. The adaptive switch level voltage VASL can be considered as the sum of the voltage drop level at the second resistor R2 and the base-emitter voltage VBE. Therefore, when the voltage drop component of the second resistor R2 increases in the adaptive switch level voltage VASL, the voltage proportionality characteristic of the adaptive switch level voltage VASL increases. That is, if the size (e.g., resistance) of the second resistor R2 increases, the slope of the adaptive switch level voltage VASL with respect to temperature can increase. On the other hand, when the voltage drop component of the second resistor R2 decreases in the adaptive switch level voltage VASL, the voltage proportionality characteristic of the adaptive switch level voltage VASL decreases. That is, if the size of the second resistor R2 decreases, the slope of the adaptive switch level voltage VASL with respect to temperature will decrease.

[0048] The characteristic change of the adaptive switching level voltage VASL according to the adjustment of the first resistor R1 or the second resistor R2 in the switch control voltage generator 110a has been briefly described. In the switch control voltage generator 110a of the present inventive concept, the slope of the adaptive switching level voltage VASL with respect to temperature or the relative amplitude with respect to the base-emitter voltage VBE can be freely adjusted by selecting the first resistor R1 and the second resistor R2.

[0049] Figure 4 is a circuit diagram illustrating a bandgap reference generator using a switch-controlled voltage generator according to some example embodiments of the inventive concept. Figure 4 The bandgap reference generator 150 performs chopping or trimming using the adaptive switching level voltage VASL generated from the switch control voltage generator 110 a. The switch control signals VSWT, VSWC1 and VSWC2 for chopping or trimming are generated by the switch controller 130 .

[0050] The switch control voltage generator 110a includes a PMOS transistor PM1, a bipolar junction transistor Q1, and a first resistor R1 and a second resistor R2. The switch control voltage generator 110a can generate an adaptive switch level voltage VASL using a base-emitter voltage VBE of the bipolar junction transistor Q1. The PMOS transistor PM1 connected to the source of the power supply voltage VDD performs Figure 2 That is, the reference voltage V output from the amplifier 156 is REFis provided to the gate of the PMOS transistor PM1. The reference voltage VREF is one of the output voltages of the bandgap reference generator 150 and maintains a constant level even when the temperature changes. Therefore, the PMOS transistor PM1 can convert the reference current I REF Transmitted to the first resistor R1 and the second resistor R2. According to the reference current I REF The first current I CTAT is supplied to the first resistor R1, and the second resistor R2 and the diode-connected bipolar junction transistor Q1 are supplied with a second current I PTAT Therefore, the switch control voltage generator 110a can generate an adaptive switch level voltage VASL that is lower than the withstand voltage (eg, 0.95V) of the switch transistor and has a slope with respect to temperature greater than the slope of the base-emitter voltage VBE with respect to temperature.

[0051] The switch controller 130 generates switch control signals VSWT, VSWC1, and VSWC2 using the clock signal CLK and the adaptive switch level voltage VASL. The switch control signals VSWT, VSWC1, and VSWC2 are switch signals for controlling the trimming circuit 152 or the chopping circuits 154 and 158 of the bandgap reference generator 150. The trimming circuit 152 or the chopping circuits 154 and 158 may include digitally driven low voltage transistors. The switch controller 130 may use the switch control signal VSWT to control the resistance of the trimming circuit 152 of the bipolar junction transistor Q3. The magnitude of the emitter current of the bipolar junction transistor Q3 may be controlled by controlling the resistance of the trimming circuit 152.

[0052] The switch controller 130 can control the chopper circuits 154 and 158 using the switch control signals VSWC1 and VSWC2 for eliminating the offset between the differential signals of the amplifier 156. The levels of the switch control signals VSWT, VSWC1, and VSWC2 are generated based on the adaptive switch level voltage VASL. Therefore, problems such as leakage current or turn-off failure that may occur depending on the temperature of the low voltage transistors included in the trimming circuit 152 or the chopper circuits 154 and 158 can be limited or prevented.

[0053] The bandgap reference generator 150 generates a bandgap reference voltage VBGR that maintains a constant voltage level even when the temperature changes. The bandgap reference generator 150 includes bipolar junction transistors Q2 and Q3, a trimming circuit 152, chopping circuits 154 and 158, an amplifier 156, PMOS transistors PM2, PM3 and PM4, and resistors R3, R4 and Ro.

[0054] The basic operation of the bandgap reference generator 150 is based on the temperature-compensated CTAT characteristic provided by using the base-emitter voltage VBE of the bipolar junction transistor Q3. That is, the bandgap reference generator 150 can generate a bandgap reference voltage VBGR having low temperature dependency by using the temperature-compensated CTAT characteristic of the base-emitter voltage VBE. For example, the current I flowing through the PMOS transistor PM3 constituting the current mirror 1 It can be expressed as the emitter current I of the bipolar junction transistor Q3 2 and the current I flowing through resistor R4 3 In addition, due to the current I 1 The mirrored current also flows through the output resistor Ro, so the bandgap reference voltage VBGR can be expressed by the following equation 1.

[0055] [Equation 1]

[0056]

[0057] 'Vt' represents a thermal voltage that increases in proportion to temperature, 'N' represents the number of parallel connections of the bipolar junction transistor Q3, and 'VBE' represents the base-emitter voltage of the bipolar junction transistor Q3. Therefore, it can be seen that the temperature dependency of the bandgap reference voltage VBGR can be controlled by adjusting the trimming resistor Rt of the trimming circuit 152. Therefore, it can be seen that by setting the trimming resistor Rt of the trimming circuit 152, the bandgap reference voltage VBGR can be maintained at a constant level regardless of temperature changes.

[0058] To this end, the trimming circuit 152 provides a function of a variable resistor for adjusting the resistance value of the trimming resistor Rt by trimming a plurality of resistors connected in series using a plurality of low-voltage switches. The trimming circuit 152 receives a switch control signal VSWT generated based on the adaptive switch level voltage VASL. The level of the switch control signal VSWT may be provided in the form of a slope with respect to temperature that is greater than the increase with respect to temperature of the base-emitter voltage VBE. For example, the switch of the trimming circuit 152 may be a digital low-voltage transistor having a withstand voltage of 0.95V. In some cases, at low temperatures, the gate voltage of the low-voltage transistor is lower than the base-emitter voltage VBE and may not be completely turned off. However, as Figure 3DAs shown, even at low temperature (T0, for example, -55°C), the adaptive switch level voltage VASL of the inventive concept is generated to be higher than the base-emitter voltage VBE. The switch control signal VSWT generated using the adaptive switch level voltage VASL can maintain a value higher than the base-emitter voltage VBE even at low temperature. Even at high temperature, the switch control signal VSWT is higher than the base-emitter voltage VBE, so that the leakage current of the low voltage switch turned off for trimming can be effectively blocked.

[0059] The chopper circuits 154 and 158 are switched at a specific frequency to effectively eliminate the offset existing between the differential signals of the amplifier 156. For example, the positive input terminal (+) and the negative input terminal (-) of the amplifier 156 are virtual ground terminals maintained at the same voltage by the bipolar junction transistors Q2 and Q3. The offset as the voltage difference between the positive input terminal (+) and the negative input terminal (-) provides an offset to the output voltage of the amplifier 156, thereby reducing the accuracy of the bandgap reference voltage VBGR. Therefore, the chopper circuits 154 and 158 use alternating switches to eliminate the offset. The low-voltage transistors used in the chopper circuits 154 and 158 can be, for example, digital low-voltage transistors having a withstand voltage or breakdown voltage of 0.95V. If the gate voltage of the low-voltage transistor is lower than the base-emitter voltage VBE at low temperatures, a turn-off failure in which the transistor is not completely turned off may occur. Alternatively, even at high temperatures, the chopping effect can be reduced due to leakage current. However, as Figure 3D As shown, even at a low temperature (T0, for example, -55°C), the adaptive switch level voltage VASL of the inventive concept is provided to be higher than the base-emitter voltage VBE. Even at a low temperature, the switch control signals VSWC1 and VSWC2 generated from the adaptive switch level voltage VASL can maintain a value higher than the base-emitter voltage VBE. Even at a high temperature, the switch control signals VSWC1 and VSWC2 are higher than the base-emitter voltage VBE, so that the leakage current of the low voltage switch turned off for chopping can be effectively blocked.

[0060] Here, PNP-type bipolar junction transistors Q1, Q2, and Q3 have been described with respect to some example embodiments of the inventive concept. However, the inventive concept is not limited to the disclosure herein, and various modifications are possible. For example, the bipolar junction transistors Q1, Q2, and Q3 of the inventive concept have been described as PNP-types commonly used in CMOS semiconductor processes, but it will be well understood that in some other example embodiments, they may be NPN-type bipolar junction transistors.

[0061] The structure of the bandgap reference generator 150 that performs chopping and trimming using the adaptive switching level voltage VASL according to some example embodiments of the inventive concept has been briefly described. The trimming circuit 152 and the chopping circuits 154 and 158 (including low voltage transistors) use the adaptive switching level voltage VASL, which has a higher level than the base-emitter voltage VBE and has a greater slope with respect to temperature than the slope of the base-emitter voltage VBE with respect to temperature. Therefore, the reliability of the trimming and chopping operations of the bandgap reference generator 150 can be ensured.

[0062] Figure 5A and Figure 5B are circuit diagrams according to some example embodiments, which respectively show Figure 4 The trimming circuit and chopping circuit. Figure 5A The trimming circuit 152 is connected between a first node N1 connected to the positive input terminal (+) of the amplifier 156 and a second node N2 connected to the bipolar junction transistor Q3. The emitter current I 2 The size of can be controlled by the trimming resistor Rt set in the trimming circuit 152.

[0063] The trimming circuit 152 includes a plurality of series resistors RD1 to RDn and switches P1 to Pn-1 that bypass the first node N1 and each of the series resistors RD1 to RDn. For example, each of the switches P1 to Pn-1 may be formed by a low voltage transistor having a withstand voltage of 0.95V. If all of the switch control signals VSWT1 to VSWTn-1 are at a high level, all of the switches P1 to Pn-1 are turned off, and the trimming resistor Rt is the sum of the series resistors RD1 to RDn. On the other hand, for example, when only the switch control signals VSWT1 and VSWT2 are provided at a low level and the remaining switch control signals VSWT3 to VSWTn-1 are provided at a high level, the switches P1 and P2 are turned on, and the switches P3 to Pn-1 will be turned off. Then, the trimming resistor Rt is set to a size obtained by subtracting the two resistors RD1 and RD2 from the sum of the series resistors RD1 to RDn.

[0064] The switches P1 to Pn-1 of the trimming circuit 152 may be low voltage transistors used in digital circuits and have a withstand voltage of about 0.95 V. The switches P1 to Pn-1 may be controlled using switch control signals VSWT1 to VSWTn generated using an adaptive switch level voltage VASL. Therefore, even at high temperatures, a gate voltage higher than the base-emitter voltage VBE may be provided to turn off the switches P1 to Pn-1, thereby blocking leakage current.

[0065] The switches P1 to Pn-1 are shown as PMOS type transistors, but the inventive concept is not limited thereto. It will be well understood that in some other example embodiments, the switches P1 to Pn-1 may be implemented with NMOS type transistors.

[0066] refer to Figure 5B , the chopper circuit 154 is configured using a plurality of switches P11 to P14. The switches P11 to P14 may be low voltage transistors having a withstand voltage of 0.95V, for example, used in digital circuits. The chopper circuit 154 repeatedly crosses and transmits the input differential voltages V1 and V3 to the two input terminals (+, -) of the amplifier 156 using switches P11 to P14. Switches P12 and P13 are switched by a switch control signal VSWC (e.g., VSWC1), and switches P11 and P14 are switched by an inverted switch control signal / VSWC. Then, the offsets of the differential voltages V1 and V3 sent from the nodes N1 and N3 corresponding to the virtual ground terminals, respectively, may be eliminated.

[0067] The switch control signals VSWC and / VSWC are generated using the adaptive switch level voltage VASL. Therefore, at low and high temperatures, a gate voltage of the turn-off switches P11 to P14 that is higher than the base-emitter voltage VBE can be provided, thereby effectively blocking leakage current. The switches P11 to P14 are shown as PMOS type transistors, but the inventive concept is not limited thereto. It will be well understood that in some other example embodiments, the switches P11 to P14 can be implemented with NMOS type transistors.

[0068] Figure 6 is a diagram showing some other exemplary embodiments of the present invention. Figure 1 The circuit diagram of the switch controlled voltage generator. Figure 6 , the switch control voltage generator 110b includes a first current source 111a, a second current source 111b, a bipolar junction transistor Q1, and a first resistor R1 and a second resistor R2. The switch control voltage generator 110b can stably generate an adaptive switching level voltage VASL using a base-emitter voltage VBE of the bipolar junction transistor Q1. The switch control voltage generator 110b can ensure the operational reliability of the bipolar junction transistor Q1 by using the second current source 111b.

[0069] Provides the first reference current I even when the temperature changes REF1 The first current source 111a with a constant level converts the first current I CTAT is supplied to the first resistor R1. In addition, the first current source 111a can supply the second current I PTAT The first current source 111a can maintain a first reference current I with respect to temperature changes.REF1 For example, the first current source 111a may be a current source 111b which is a current source of a bandgap reference generator 150 (see Figure 1 ) generates a bandgap reference voltage to mirror the current.

[0070] When the first reference current I REF1 When supplied by the first current source 111a, a base-emitter voltage VBE is formed in the diode-connected bipolar junction transistor Q1. The base-emitter voltage VBE of the bipolar junction transistor Q1 exhibits a temperature-compensated CTAT characteristic that decreases as the temperature increases. In addition, like the base-emitter voltage VBE, the adaptive switch level voltage VASL also has a characteristic of decreasing as the temperature increases. When the adaptive switch level voltage VASL decreases as the temperature increases, the first current I flowing through the first resistor R1 CTAT The second current I flowing through the second resistor R2 decreases as the temperature increases. PTAT By changing the first reference current I from a constant value according to the temperature REF1 Subtract the first current I CTAT Therefore, the second current I flowing through the second resistor R2 PTAT The voltage V proportional to the temperature will increase with the increase of temperature. That is, the voltage V proportional to the temperature formed at the second resistor R2 is PTAT Will have a voltage characteristic that is proportional to temperature.

[0071] The adaptive switch level voltage VASL is proportional to the base-emitter voltage VBE and the temperature voltage V formed at the second resistor R2. PTAT Since the base-emitter voltage VBE basically exhibits a temperature complementary CTAT characteristic, the temperature proportional voltage V PTAT The adaptive switch level voltage VASL exhibits a temperature complementary characteristic. However, by forming a temperature proportional voltage V PTAT The temperature proportional characteristic of the base-emitter voltage VBE is added to the temperature complementary characteristic of the base-emitter voltage VBE, and the adaptive switching level voltage VASL appears in the form of an increased slope greater than the slope of the base-emitter voltage VBE with respect to temperature. The adaptive switching level voltage VASL can be generated at a level lower than the withstand voltage (e.g., 0.95V) of the switching transistor used for chopping or trimming. That is, the adaptive switching level voltage VASL can be generated as a temperature complementary voltage that is close to the base-emitter voltage VBE at low temperatures but is higher than the base-emitter voltage VBE by a certain level at high temperatures.

[0072] The first reference current I supplied from the first current source 111a REF1The first current I is branched into the first resistor R1. CTAT and a second current I flowing to the second resistor R2 PTAT Therefore, when the second current I PTAT When not fully supplied, the bipolar junction transistor Q1 may not be activated. In this case, the adaptive switch level voltage VASL only reflects the effect of the voltage drop of the first resistor R1 which is independent of the base-emitter voltage VBE.

[0073] Therefore, according to Figure 6 In some example embodiments of the present inventive concept shown in FIG. 1 , the switch control voltage generator 110 b may use the second current source 111 b to directly provide the second reference current I at the emitter of the bipolar junction transistor Q1. REF2 Even if due to various reasons the second current I PTAT is not fully supplied, the second current source 111b also stably supplies the second reference current I REF2 Therefore, the cut-off state of the bipolar junction transistor Q1 can be limited and / or prevented. Therefore, the adaptive switching level voltage VASL having a slope with respect to temperature greater than the slope with respect to temperature of the base-emitter voltage VBE can be stably provided.

[0074] The second reference current I provided by the second current source 111b REF2 The magnitude of the first reference current I REF1 For example, the second reference current I REF2 The amplitude of the first reference current I REF1 The bipolar junction transistor Q1 has been described as an example of a PNP type commonly used in CMOS semiconductor processes, but it will be well understood that in other example embodiments, it may be an NPN type bipolar junction transistor.

[0075] The switch control voltage generator 110b according to some other example embodiments may generate an adaptive switch level voltage VASL having an increased slope with respect to temperature greater than the slope with respect to temperature of the base-emitter voltage VBE. A second current source 111b may be added to stably supply an operating current of the bipolar junction transistor Q1. Therefore, according to the switch control voltage generator 110b according to some other example embodiments, a stable operation of the bipolar junction transistor Q1 may be ensured.

[0076] Figure 7 It is shown that the use Figure 6 Circuit diagrams of bandgap reference generators of some other example embodiments of switch-controlled voltage generators. Figure 7The bandgap reference generator 150 may perform chopping or trimming using the adaptive switch level voltage VASL generated from the switch control voltage generator 110b. The switch control signals VSWT, VSWC1, and VSWC2 for chopping or trimming are generated by the switch controller 130 based on the adaptive switch level voltage VASL.

[0077] The switch control voltage generator 110b includes PMOS transistors PM1 and PM5, a bipolar junction transistor Q1, and a first resistor R1 and a second resistor R2. The switch control voltage generator 110b generates an adaptive switch level voltage VASL using a base-emitter voltage VBE of the bipolar junction transistor Q1. The PMOS transistors PM1 and PM5, whose gates are provided with a reference voltage VREF and whose sources are connected to a power supply voltage VDD, perform Figure 6 The current sources 111a and 111b of the PMOS transistors 150 are configured to function as current sources 111a and 111b. That is, the reference voltage VREF output from the amplifier 156 is supplied to the gates of the PMOS transistors PM1 and PM5. The reference voltage VREF is one of the output voltages of the bandgap reference generator 150, and is a voltage that maintains a constant level even when the temperature changes. Therefore, the PMOS transistors PM1 and PM5 can supply the reference current I that is not affected by temperature changes through the current mirror. REF1 and I REF2 The first reference current I REF1 is transmitted to the first resistor R1 and the second resistor R2, and the second reference current I REF2 is supplied as a current for activating the operation of the bipolar junction transistor Q1. In some example embodiments, the sizes of the PMOS transistors PM1 and PM5 may be based on the second reference current I REF2 and the first reference current I REF1 The size ratio is determined.

[0078] Based on the reference current I REF1 and I REF2 The first current I CTAT is supplied to the first resistor R1, and the second current I PTAT is supplied to the second resistor R2 and the diode-connected bipolar junction transistor Q1. Thus, as mentioned above with reference Figure 6 As described above, the switch control voltage generator 110 b stabilizes the adaptive switch level voltage VASL, which is lower than the withstand voltage of the switch transistor and has a slope with respect to temperature greater than the slope of the base-emitter voltage VBE with respect to temperature.

[0079] The switch controller 130 and the bandgap reference generator 150 can be used with Figure 4The switch controller and the bandgap reference generator are substantially the same, and a description thereof will be omitted.

[0080] A technique for stably generating an adaptive switching level voltage VASL using a switch control voltage generator 110b according to some other example embodiments of the inventive concept has been described. The reliability of chopping and trimming of the bandgap reference generator 150 can be increased by using a stable level of the adaptive switching level voltage VASL generated by the switch control voltage generator 110b. Therefore, the bandgap reference generator 150 of the inventive concept can provide a high-quality bandgap reference voltage VBGR capable of compensating for temperature dependency.

[0081] Figure 8 is a flow chart illustrating a method of controlling a low voltage switch for dynamic element matching, trimming or chopping of a bandgap reference generator according to some example embodiments of the inventive concept. Figure 8 , through the adaptive switching level voltage VASL generated by the switch control voltage generator 110, the low voltage switch can be stably controlled regardless of the temperature.

[0082] In step S110, the switch controls the voltage generator 110 (see Figure 1 ) generates an adaptive switch level voltage VASL. The switch control voltage generator 110 can utilize Figure 2 or Figure 6 For example, the switch control voltage generator 110 includes a current source 111 (which may be, for example, Figure 4 The PMOS transistor PM1 shown in the figure), the bipolar junction transistor Q1, and the first resistor R1 and the second resistor R2, the current source 111 generates a reference current that maintains a constant level relative to the temperature. IREF The amplitude and slope of the adaptive switch level voltage VASL can be set to a target value by the amplitude of the first resistor R1 and the second resistor R2. Figure 2 or Figure 6 The adaptive switching level voltage VASL is set to a relatively higher value than the base-emitter voltage VBE of the bipolar junction transistor Q1 over the entire temperature range in the manner described in . The adaptive switching level voltage VASL can be generated in the form of a slope with respect to temperature that is greater than the slope with respect to temperature of the base-emitter voltage VBE.

[0083] In step S120, the switch control signals VSWT, VSWC1, and VSWC2 may be generated using the adaptive switch level voltage VASL provided from the switch control voltage generator 110. For example, the switch controller 130 (see Figure 1) generates switch control signals VSWT, VSWC1, and VSWC2 corresponding to the level of the adaptive switch level voltage VASL. The switch control signals VSWC1 and VSWC2 provided to the chopper circuits 154 and 158 may be provided in the form of complementary signals switched at a specific frequency (see, for example, Figure 5B The switch control signal VSWT provided to the trimming circuit 152 may be generated as a set of control signals for turning on or off a switch including a plurality of low voltage transistors (see, for example, Figure 5A ). The high levels of these switch control signals VSWC1 and VSWC2 can be made equal to the temperature adaptive switch level voltage VASL.

[0084] In step S130, the trimming circuit 152 or the chopping circuits 154 and 158 (see Figure 1 ) and a dynamic element matching circuit (not shown) perform trimming, dynamic element matching or chopping operations in response to switch control signals VSWT, VSWC1 and VSWC2. The trimming circuit 152 or chopping circuits 154 and 158 may include digitally driven low voltage transistors. The resistance of the trimming circuit 152 is set to control the emitter current of the bipolar junction transistor Q3 through the switch control signal VSWT. The offset of the amplifier 156 can be eliminated by supplying the switch control signals VSWC1 and VSWC2 to the chopping circuits 154 and 158.

[0085] The operational reliability of the low voltage transistor included in the trimming circuit 152 or the chopping circuits 154 and 158 can be increased by the switch control signals VSWT, VSWC1, and VSWC2 generated based on the adaptive switch level voltage VASL. That is, problems such as leakage current or turn-off failure of the low voltage transistor that may occur due to temperature changes can be limited or prevented by the switch control signals VSWT, VSWC1, and VSWC2.

[0086] Fig. 9 is a circuit diagram illustrating a bandgap reference generator using a switch-controlled voltage generator according to some other example embodiments of the inventive concept. Fig. 9 The bandgap reference generator 150a can use the adaptive switch level voltage VASL generated from the switch control voltage generator 110b to perform chopping or trimming of various devices. The switch control signals VSWT, VSWC1 and VSWC2 for chopping or trimming are generated by the switch controller 130 based on the adaptive switch level voltage VASL.

[0087] The switch control voltage generator 110b includes PMOS transistors PM1 and PM5, a bipolar junction transistor Q1, and first and second resistors R1 and R2. The switch control voltage generator 110b generates an adaptive switch level voltage VASL using a base-emitter voltage VBE of the bipolar junction transistor Q1. Figure 7 The circuit structure of is shown as an example of the switch control voltage generator 110b, but the inventive concept is not limited thereto. That is, it should be understood that in other example embodiments, the switch control voltage generator 110b may be composed of a single current source. Figure 4 The switch control voltage generator 110a is replaced.

[0088] The switch controller 130a generates switch control signals VSWT, VSWC1, and VSWC2 using the clock signal CLK and the adaptive switch level voltage VASL. The switch control signals VSWT, VSWC1, and VSWC2 are switch signals for the trimming circuit 152, the chopping circuits 154 and 158, and the elements R3, R4, PM2, PM3, and PM4 of the bipolar junction transistors Q2 and Q3 connected to the bandgap reference generator 150a. The trimming circuit 152, the chopping circuits 154 and 158, and the elements R3, R4, PM2, PM3, and PM4 may include digitally driven low voltage transistors.

[0089] The switch controller 130a can use the switch control signal VSWT to set the resistance of the trimming circuit 152 of the bipolar junction transistor Q3 and the resistor elements R3 and R4. In addition, the switch controller 130a can use the switch control signal VSWT to perform trimming between the PMOS transistors PM2, PM3 and PM4 used as current sources through mirroring. That is, the switch control signal VSWT can be used to trim the characteristic adjustment (for example, the channel size) so as to set the amplitude of the current flowing through each of the PMOS transistors PM2, PM3 and PM4 equally. The control method of the chopping circuits 154 and 158 and the trimming circuit 152 of the switch controller 130a is the same as that described above. Figure 7 Therefore, the description of these will be omitted.

[0090] The bandgap reference generator 150a generates a bandgap reference voltage VBGR that maintains a constant voltage level even when the temperature changes. The bandgap reference generator 150a includes bipolar junction transistors Q2 and Q3, a trimming circuit 152, chopper circuits 154 and 158, an amplifier 156, PMOS transistors PM2, PM3 and PM4, and resistors R3, R4 and Ro. For example, in the bandgap reference generator 150a, various elements Rt, R3, R4, PM2, PM3 and PM4 connected to the bipolar junction transistor Q3 can be trimmed by the switch control signal VSWT. The switch control signal VSWT generated from the adaptive switch level voltage VASL can maintain a value higher than the base-emitter voltage VBE even at low temperatures. Even at high temperatures, the switch control signal VSWT is higher than the base-emitter voltage VBE, so that the leakage current of the low voltage switch turned off for trimming can be effectively blocked.

[0091] The bandgap reference generator 150a can effectively eliminate the offset between the differential signals of the amplifier 156 using the chopping circuits 154 and 158. The chopping circuits 154 and 158 can be switched by the switch control signals VSWC1 and VSWC2, respectively. Even at low temperatures, the switch control signals VSWC1 and VSWC2 generated from the adaptive switch level voltage VASL can maintain a value higher than the base-emitter voltage VBE. Even at high temperatures, the switch control signals VSWC1 and VSWC2 are higher than the base-emitter voltage VBE, so that the leakage current of the low voltage switch turned off for chopping can be effectively blocked.

[0092] PNP-type bipolar junction transistors Q1, Q2, and Q3 have been described as examples for explaining the advantages of the inventive concept. However, the inventive concept is not limited thereto. For example, the bipolar junction transistors Q1, Q2, and Q3 of the inventive concept have been described as PNP-types commonly used in CMOS semiconductor processes, but it will be well understood that in other example embodiments, they may be NPN-type bipolar junction transistors.

[0093] The structure of the bandgap reference generator 150a that performs chopping and trimming using the adaptive switching level voltage VASL according to some example embodiments of the inventive concept has been briefly described. The chopping circuits 154 and 158 including the low voltage transistor, the trimming circuit 152, and the various elements R3, R4, PM2, PM3, and PM4 can be switched using the adaptive switching level voltage VASL, which has a level higher than the base-emitter voltage VBE and has a slope with respect to temperature greater than the slope with respect to temperature of the base-emitter voltage VBE. Therefore, according to the inventive concept, the reliability of the trimming and chopping operations of the bandgap reference generator 150a can be ensured.

[0094] Fig.10 is a circuit diagram illustrating a bandgap reference generator using a switch-controlled voltage generator according to some other example embodiments of the inventive concept. Fig.10 The bandgap reference generator 150b can use the adaptive switch level voltage VASL generated from the switch control voltage generator 110b to perform switching, chopping or trimming of various devices. The switch control signals VSWDEM, VSWT, VSWC1 and VSWC2 for switching, chopping or trimming are generated by the switch controller 130b based on the adaptive switch level voltage VASL.

[0095] The switch control voltage generator 110b includes PMOS transistors PM1 and PM5, a bipolar junction transistor Q1, and first and second resistors R1 and R2. The switch control voltage generator 110b generates an adaptive switch level voltage VASL using a base-emitter voltage VBE of the bipolar junction transistor Q1. Figure 7 The circuit structure of is shown as an example of the switch control voltage generator 110b, but the inventive concept is not limited thereto. That is, it should be understood that in some example embodiments, the switch control voltage generator 110b may be composed of a single current source. Figure 4 The switch control voltage generator 110a is replaced.

[0096] The switch controller 130b generates switch control signals VSWDEM, VSWT, VSWC1, and VSWC2 using the clock signal CLK and the adaptive switch level voltage VASL. The switch control signals VSWDEM, VSWT, VSWC1, and VSWC2 are provided to the dynamic element matching circuit 151, the trimming circuit 152 or the chopping circuits 154 and 158 of the bandgap reference generator 150b, and the elements R3, R4, PM2, PM3, and PM4 connected to the bipolar junction transistors Q2 and Q3. The dynamic element matching circuit 151, the trimming circuit 152, the chopping circuits 154 and 158, and the elements R3, R4, PM2, PM3, and PM4 may include digitally driven low voltage transistors.

[0097] The switch controller 130b may switch the dynamic element matching circuit 151 using the element matching signal VSWDEM. The dynamic element matching circuit 151 periodically cycles the outputs of the PMOS transistors PM2, PM3, and PM4 operating as current sources by mirroring. For example, the dynamic element matching circuit 151 may switch the drain of the PMOS transistor PM2 to be connected to one side of the trimming circuit 152 instead of the bipolar junction transistor Q2. In addition, the dynamic element matching circuit 151 may switch to connect the drain of the PMOS transistor PM3 to the output resistor Ro side instead of the trimming circuit 152. In addition, the dynamic element matching circuit 151 may switch the drain of the PMOS transistor PM4 to be connected to one side of the bipolar junction transistor Q2 instead of the output resistor Ro. The switching may be repeated according to a desired (and / or alternatively predetermined) period. The PMOS transistors PM2, PM3, and PM4 of the dynamic element matching circuit 151 may maintain the same magnitude of current provided by the mirroring through the dynamic element matching action. In addition to device matching operations, switch controller 130b may perform switching for chopping or trimming of bandgap reference generator 150b.

[0098] The bandgap reference generator 150b may include a dynamic element matching circuit 151 and Fig. 9 By reducing the offset of the current mirrored by the switching of the dynamic element matching circuit 151, a bandgap reference voltage VBGR having high reliability even when a temperature change occurs is generated.

[0099] The structure of the bandgap reference generator 150b that performs dynamic device matching, chopping, and trimming using the adaptive switching level voltage VASL according to some example embodiments of the inventive concept has been briefly described. The dynamic element matching circuit 151, the chopping circuits 154 and 158, the trimming circuit 152, and the various elements R3, R4, PM2, PM3, and PM4 including the low voltage transistor can be switched using the adaptive switching level voltage VASL, which has a higher level than the base-emitter voltage VBE and a greater slope with respect to temperature than the slope of the base-emitter voltage VBE with respect to temperature. Therefore, according to the inventive concept, the reliability of the dynamic element matching, trimming, and chopping operations of the bandgap reference generator 150b can be ensured.

[0100] One or more of the elements disclosed above may include or be implemented in a processing circuit, such as hardware including logic circuits; a hardware / software combination, such as a processor executing software; or a combination thereof. For example, the processing circuit may include, but is not limited to, a central processing unit (CPU), an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable gate array (FPGA), a system on a chip (SoC), a programmable logic unit, a microprocessor, an application specific integrated circuit (ASIC), etc.

[0101] The example embodiments described for carrying out the inventive concept should not be interpreted as limiting. In addition to the above-described embodiments, the inventive concept may include simple design changes or easily changeable embodiments. The inventive concept will include techniques that can be easily modified and implemented using the embodiments. Therefore, the scope of the inventive concept should not be limited to the above-described embodiments, and should be defined by the claims and the equivalents of the claims and the claims described later.

Claims

1. A semiconductor device, comprising: a bandgap reference generator configured to generate a reference voltage; a switch control voltage generator configured to generate a first reference current based on the reference voltage and to generate an adaptive switch level voltage by distributing the first reference current to a first path and a second path, the first path including a first resistor, and the second path including a second resistor and a first bipolar junction transistor connected in series; as well as a switch controller configured to generate a switch control signal for controlling a switch included in the bandgap reference generator based on the adaptive switch level voltage, The adaptive switch level voltage has a slope relative to temperature that is greater than a slope relative to temperature of a base-emitter voltage of the first bipolar junction transistor.

2. The semiconductor device according to claim 1, wherein The switch control signal includes a first switch control signal and a second switch control signal, The bandgap reference generator comprises: a first transistor configured to mirror and generate a first current in response to the reference voltage; a second bipolar junction transistor configured to receive the first current and generate a first base-emitter voltage; a second transistor configured to mirror and generate a second current in response to the reference voltage; a trimming circuit configured to have a resistance value set according to the first switch control signal; a third diode-connected bipolar junction transistor, the third diode-connected bipolar junction transistor being connected in series between the trimming circuit and ground, the third diode-connected bipolar junction transistor being configured to generate a second base-emitter voltage; an amplifier connected to the first base-emitter voltage and to the second base-emitter voltage through the trimming circuit; and A chopper circuit is configured to chop the first base-emitter voltage and the second base-emitter voltage to provide a chopping voltage in response to the second switch control signal, and transmit the chopping voltage to an input terminal of the amplifier.

3. The semiconductor device according to claim 2, wherein: The bandgap reference generator comprises: a resistive element configured to bias the second bipolar junction transistor and the third diode-connected bipolar junction transistor, respectively; and a dynamic element matching circuit configured to periodically cycle the output currents of the first transistor and the second transistor, The trimming circuit, the chopper circuit, the resistor element and the dynamic element matching circuit include a low-voltage transistor with a withstand voltage of 0.95V as a switch.

4. The semiconductor device according to claim 1, wherein: The switch control voltage generator includes a first PMOS transistor having one terminal connected to a power supply voltage, the first PMOS transistor being configured to transmit the reference current to a first node based on the reference voltage, The first resistor is connected between the first node and ground, and a first bipolar junction transistor connected in series with the second resistor is connected between the first node and ground.

5. The semiconductor device according to claim 4, wherein: The slope of the adaptive switch level voltage is adjusted based on the resistance of the second resistor.

6. The semiconductor device according to claim 4, wherein: The switch control voltage generator includes a second PMOS transistor having one terminal connected to the power supply voltage, the second PMOS transistor being configured to supply a second reference current to an emitter terminal of the first bipolar junction transistor based on the reference voltage.

7. The semiconductor device according to claim 6, wherein: The second reference current is set to 1 / 4 of the first reference current.

8. The semiconductor device according to claim 1, wherein: the adaptive switch level voltage is greater than the base-emitter voltage by a first voltage difference at a first temperature and is greater than the base-emitter voltage by a second voltage difference at a second temperature higher than the first temperature, The second voltage difference is greater than the first voltage difference.

9. A switch-controlled voltage generator, comprising: a first current source connected to a power supply voltage, the first current source being configured to deliver a first reference current having a constant level with respect to temperature to the first node; a first resistor connected between the first node and ground; a second resistor having one end connected to the first node; as well as a diode-connected bipolar junction transistor connected between the other end of the second resistor and ground, The first resistor, the second resistor, and the diode-connected bipolar junction transistor are configured to generate an adaptive switch level voltage at the first node, the slope and magnitude of the offset of the adaptive switch level voltage with respect to temperature being adjustable based on the resistance of the first resistor and the second resistor.

10. The switch-controlled voltage generator of claim 9, wherein: A temperature complementary current flows through the first resistor and a temperature proportional current flows through the second resistor.

11. The switch-controlled voltage generator of claim 9, wherein: The first current source includes a first transistor configured to supply the first reference current by mirroring from the power supply voltage based on a reference voltage provided from a bandgap reference generator.

12. The switch-controlled voltage generator of claim 11, wherein: The diode-connected bipolar junction transistor is a PNP-type transistor having a base terminal and a collector terminal connected to ground.

13. The switch-controlled voltage generator of claim 9, wherein: the adaptive switch level voltage is greater than a base-emitter voltage of the diode-connected bipolar junction transistor by a first voltage difference at a first temperature and is greater than the base-emitter voltage by a second voltage difference at a second temperature higher than the first temperature, The second voltage difference is greater than the first voltage difference.

14. The switch-controlled voltage generator of claim 13, wherein: The slope of the adaptive switch level voltage with respect to temperature is greater than the slope of the base-emitter voltage with respect to temperature.

15. The switch-controlled voltage generator of claim 9, further comprising: A second current source, connected to the supply voltage, is configured to directly supply a second reference current of constant magnitude with respect to temperature to an emitter terminal of the diode-connected bipolar junction transistor.

16. The switch-controlled voltage generator of claim 15, wherein: The amplitude of the second reference current is smaller than the amplitude of the first reference current.

17. The switch-controlled voltage generator of claim 9, wherein: The adaptive switching level voltage is provided as a switching voltage of a chopping circuit or a trimming circuit of a bandgap reference generator.

18. A method for generating a switching voltage for switching of a bandgap reference generator, comprising: generating a reference current based on a reference voltage provided from the bandgap reference generator; generating an adaptive switch level voltage by distributing the reference current to a first path and a second path, the first path including a first resistor and the second path including a second resistor connected in series and a diode-connected bipolar junction transistor; generating a switch control signal for controlling a switch element of the bandgap reference generator based on the adaptive switch level voltage; as well as The switch control signal is applied to a switching element of the bandgap reference generator.

19. The method for generating a switching voltage as described in claim 18 also includes setting the resistance of the second resistor so that the adaptive switching level voltage has a slope relative to temperature that is greater than the slope of the base-emitter voltage of the diode-connected bipolar junction transistor relative to temperature.

20. The method for generating a switching voltage as claimed in claim 18, wherein: The switching element includes at least one of a dynamic element matching circuit, a chopping circuit and a trimming circuit, and The switching elements each include a low voltage transistor having a withstand voltage of 0.95 V, and the switching elements perform switching in response to the switching control signal.

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