Reference source circuit
By designing a reference source circuit including switching circuits and thermal circuits, the problems of large area and high current consumption of traditional reference source circuits are solved, and the reference voltage and current output with zero temperature coefficient is realized, reducing power consumption and area occupation.
Patent Information
- Application Number
- CN202420752233.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-11
- Publication Date
- 2024-12-10
- Estimated Expiration
- 2034-04-11
AI Technical Summary
Traditional reference source circuits include transistors and op amps, resulting in large area and high current consumption, which limits the chip's integration and power consumption.
A reference source circuit including a first switching circuit, a thermal circuit, a second switching circuit and a third switching circuit are designed, and the reference of zero temperature coefficient is realized by adjusting the width-length ratio of the switching circuit and the temperature coefficient of the thermal circuit. Voltage and reference current output reduce current consumption and area occupancy.
The zero-temperature coefficient output of the reference voltage and reference current is realized, reducing the power consumption and area occupation of the circuit, and adapting chips with strict requirements on the cost and current consumption.
Smart Images
Figure CN222145438U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of reference sources, in particular to a reference source circuit. Background Art
[0002] Many chips, such as ADC (analog-to-digital converter) and DAC (digital-to-analog converter), require a stable reference voltage to ensure accurate conversion. These reference voltages must not be affected by temperature and supply voltage changes to ensure conversion accuracy. Therefore, a voltage source that is not affected by temperature and supply voltage is often required inside the chip. The usual practice to generate this reference source is to use a traditional bandgap reference (BJT+RES+op amp). The bipolar transistor base-emitter voltage difference ΔVBE has a positive temperature coefficient, while the bipolar transistor base-emitter voltage VBE has a negative temperature coefficient. If the two voltages are added, theoretically a zero temperature coefficient voltage can be achieved by designing appropriate parameters.
[0003] Traditional bandgap references include transistors, resistors, operational amplifiers and other devices. In order to achieve good characteristics during design, the ratio of transistors is usually 32:8, which results in a large area being occupied, limiting the integration of other functional modules on the chip. In addition, since the operational amplifier and its internal temperature coefficient adjustment circuit (usually two branches) consume a large current, the large current consumption directly leads to an increase in power consumption. Utility Model Content
[0004] The main purpose of the utility model is to provide a reference source circuit, aiming to solve the problem that the traditional reference source of the chip has a large area and consumes a large current, so as to better adapt to the chip with strict requirements on cost and current consumption.
[0005] In order to achieve the above-mentioned object, the reference source circuit proposed by the utility model is characterized in that the reference source circuit comprises:
[0006] a first switch circuit, wherein an input end of the first switch circuit is used to connect to a power supply, and a controlled end of the first switch circuit is used to receive a disconnection signal or a conduction signal;
[0007] Thermal circuit;
[0008] a second switch circuit, wherein an input end of the second switch circuit is electrically connected to an output end of the first switch circuit, a controlled end of the second switch circuit is electrically connected to an output end of the second switch circuit, and an output end of the second switch circuit is electrically connected to a first end of the thermistor circuit;
[0009] a third switch circuit and a fourth switch circuit, wherein the input end of the third switch circuit is electrically connected to the second end of the thermistor circuit, the input end of the fourth switch circuit is used to access a power supply, the input end of the third switch circuit is electrically connected to a controlled end of the fourth switch circuit, and the controlled end of the third switch circuit is electrically connected to an output end of the fourth switch circuit;
[0010] A voltage divider circuit, wherein a first end of the voltage divider circuit is electrically connected to an output end of the fourth switch circuit, the first end of the voltage divider circuit is used to output a reference voltage, and the other end of the voltage divider circuit is used to output a reference current;
[0011] Among them, the second switch circuit is a depletion-type switch circuit, and the third switch circuit is an enhancement-type switch circuit.
[0012] Optionally, the thermistor circuit includes:
[0013] a thermistor, wherein a first end of the thermistor is electrically connected to an output end of the second switch circuit, a second end of the thermistor is electrically connected to an input end of the third switch circuit, and a resistance value of the thermistor decreases as temperature increases, or a resistance value of the thermistor increases as temperature increases.
[0014] Optionally, the first switch circuit includes:
[0015] A first switch tube, wherein the input end of the first switch tube is used to connect to a power supply, the controlled end of the first switch tube is used to receive a disconnection signal or a conduction signal, and the output end of the first switch tube is electrically connected to the input end of the second switch circuit.
[0016] Optionally, the second switch circuit includes:
[0017] A second switch tube, the input end of the second switch tube is electrically connected to the output end of the first switch circuit, the controlled end of the second switch tube is electrically connected to the output end of the second switch tube, and the output end of the second switch tube is electrically connected to the input end of the third switch circuit; the second switch tube is a depletion type switch tube.
[0018] Optionally, the third switch circuit includes:
[0019] A third switch tube, wherein the input end of the third switch tube is electrically connected to the second end of the thermistor circuit and the controlled end of the fourth switch circuit respectively, the controlled end of the third switch tube is electrically connected to the output end of the fourth switch circuit, and the output end of the third switch tube is grounded; the third switch tube is an enhanced switch tube.
[0020] Optionally, the fourth switching circuit includes a fourth switching tube, the voltage divider circuit includes a second resistor, the input end of the fourth switching tube is used to connect to the power supply, the controlled end of the fourth switching tube is electrically connected to the input end of the third switching circuit, the output end of the fourth switching tube is respectively electrically connected to the controlled end of the third switching circuit and the first end of the second resistor, and the second end of the second resistor is grounded.
[0021] Optionally, the reference source circuit further includes:
[0022] A first current mirror circuit, wherein the first input terminal and the second input terminal of the first current mirror circuit are both used to connect to a power supply, the first output terminal of the first current mirror circuit is electrically connected to the input terminal of the fourth switch circuit, the controlled terminal of the first current mirror circuit is electrically connected to the input terminal of the fourth switch circuit, and the second output terminal of the first current mirror circuit is used to output a reference current.
[0023] Optionally, the first current mirror circuit includes:
[0024] a third resistor, a fifth switch tube, a sixth switch tube, a seventh switch tube and an eighth switch tube, wherein the input end of the sixth switch tube is used to connect to a power supply, the output end of the sixth switch tube is electrically connected to the input end of the fifth switch tube, the output end of the fifth switch tube is electrically connected to the first end of the third resistor, the second end of the third resistor is electrically connected to the input end of the fourth switch circuit, the controlled end of the sixth switch tube is electrically connected to the first end of the third resistor, the controlled end of the fifth switch tube is electrically connected to the second end of the third resistor, the input end of the seventh switch tube is used to connect to a power supply, the controlled end of the seventh switch tube is electrically connected to the controlled end of the sixth switch tube, the output end of the seventh switch tube is electrically connected to the input end of the eighth switch tube, the controlled end of the eighth switch tube is electrically connected to the controlled end of the fifth switch tube, and the output end of the eighth switch tube is used to output a reference current.
[0025] Optionally, the reference source circuit also includes N second current mirror circuits, the input ends of the N second current mirror circuits are used to connect to the power supply, the controlled end of the first second current mirror circuit is electrically connected to the controlled end of the first current mirror circuit, the controlled end of the M+1th second current mirror circuit is electrically connected to the controlled end of the Mth second current mirror circuit, and the output ends of the N second current mirror circuits are used to output a reference current; wherein, 1<M<N.
[0026] The technical solution of the utility model includes a first switch circuit, a thermistor circuit, a second switch circuit, a third switch circuit and a fourth switch circuit. The first switch circuit is turned off when receiving a disconnection signal and turned on when receiving a conduction signal, thereby playing a role in starting or closing the circuit. Since the second switch circuit is a depletion-type switch tube and its controlled end is short-circuited with the output end, the second switch circuit is in a normally open state. The voltage of the power supply is transmitted to the controlled end of the fourth switch circuit via the first switch circuit and the second switch circuit. The fourth switch circuit is turned on. Since the controlled end of the third switch circuit is electrically connected to the output end of the fourth switch circuit, the third switch circuit is also turned on. Since the input end of the fourth switch circuit is connected to the power supply, the power supply outputs a corresponding reference current via the output end of the fourth switch circuit and the voltage divider circuit. The first end of the voltage divider circuit is used to output a reference voltage, and the accuracy of the reference current and the reference voltage is related to the voltage stability of the controlled end of the fourth switch circuit. With such a configuration, the user can adjust the equivalent resistance of the voltage divider circuit according to actual needs, thereby outputting the required reference voltage or reference current. In practical applications, assuming that the second switch circuit is a depletion switch circuit, and its threshold voltage is a negative temperature coefficient and a negative value; the third switch circuit is an enhancement switch circuit, and its threshold voltage is also a negative temperature coefficient and a positive value, then the input terminal voltage of the third switch circuit is equal to the sum of the threshold voltage of the second switch circuit and the threshold voltage of the third switch circuit, and since the threshold voltage of the second switch circuit is a negative value, the input terminal voltage of the third switch circuit is also equal to the absolute value of the threshold voltage of the third switch circuit and the threshold voltage of the second switch circuit. The difference is set in this way. In actual applications, when the ambient temperature rises or falls, the threshold voltage of the second switch circuit and the threshold voltage of the third switch circuit both decrease or increase. The user can adjust the width-to-length ratio of the second switch circuit and the third switch circuit according to the needs of the actual scenario, so that the rate at which the threshold voltages of the second switch circuit and the third switch circuit change with temperature is closer or the amount of change is more matched, so that the difference, that is, the voltage at the input end of the third switch circuit, is not affected by temperature changes and remains basically unchanged, and the conduction degree of the fourth switch circuit is also not affected by temperature, so its output reference voltage is a zero temperature coefficient voltage, and the output reference current is a zero temperature coefficient current.In practical applications, due to process deviation, adjusting the width-to-length ratio of the switch circuit can effectively reduce the temperature drift of the threshold voltage, but it cannot completely eliminate it. For this reason, the process deviation can be further compensated by adjusting the temperature coefficient of the thermistor circuit. For example, when the negative temperature coefficient of the second switch circuit is larger than the negative temperature coefficient of the third switch circuit, the negative deviation can be compensated by adjusting the temperature coefficient of the thermistor circuit to a positive temperature coefficient; on the contrary, when the negative temperature coefficient of the second switch circuit is smaller than the negative temperature coefficient of the third switch circuit, the positive deviation can be compensated by adjusting the temperature coefficient of the thermistor circuit to a negative temperature coefficient. In this way, the voltage at the controlled end of the fourth switch circuit is basically not affected by temperature, thereby obtaining a reference voltage value and a reference current value that are least affected by temperature. The utility model only needs to use the temperature coefficient adjustment circuit of the first switch circuit, the second switch circuit and the third switch circuit. Compared with the traditional temperature coefficient adjustment circuit, the utility model consumes less current and does not require components such as op amps, thereby avoiding an increase in power consumption and reducing the area occupancy of the overall circuit in the applied product. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.
[0028] Figure 1 This is a schematic diagram of a module of an embodiment of the utility model;
[0029] Figure 2 This is a schematic diagram of the circuit structure of another embodiment of the utility model;
[0030] Figure 3 This is a schematic diagram of the circuit structure of another embodiment of the utility model.
[0031] Description of Figure Numbers:
[0032] Label name Label name 10 First switch circuit 50 Fourth switch circuit 20 Thermal circuit 60 The first current mirror circuit 30 Second switch circuit 70 Second current mirror circuit 40 The third switch circuit 80 Voltage divider circuit
[0033] The realization of the purpose, functional features and advantages of the utility model will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION
[0034] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.
[0035] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back...) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.
[0036] In addition, the descriptions of "first", "second", etc. in the present utility model are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in this field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present utility model.
[0037] Many chips, such as ADC (analog-to-digital converter) and DAC (digital-to-analog converter), require a stable reference voltage to ensure accurate conversion. These reference voltages must not be affected by temperature and supply voltage changes to ensure conversion accuracy. Therefore, a voltage source that is not affected by temperature and supply voltage is often required inside the chip. The usual practice to generate this reference source is to use a traditional bandgap reference (BJT+RES+op amp). The bipolar transistor base-emitter voltage difference ΔVBE has a positive temperature coefficient, while the bipolar transistor base-emitter voltage VBE has a negative temperature coefficient. If the two voltages are added, theoretically a zero temperature coefficient voltage can be achieved by designing appropriate parameters.
[0038] Traditional bandgap references include transistors, resistors, operational amplifiers and other devices. In order to achieve good characteristics during design, the ratio of transistors is usually 32:8, which results in a large area being occupied, limiting the integration of other functional modules on the chip. In addition, since the operational amplifier and its internal temperature coefficient adjustment circuit (usually two branches) consume a large current, the large current consumption directly leads to an increase in power consumption.
[0039] To this end, the utility model provides a reference source circuit, aiming to solve the problem that the traditional reference source of the chip has a large area and consumes a large current, so as to better adapt to the chip with strict requirements on cost and current consumption.
[0040] refer to Figure 1 In one embodiment of the present utility model, a reference source circuit is provided, the reference source circuit comprising:
[0041] A first switch circuit 10, wherein an input end of the first switch circuit 10 is used to connect to a power supply, and a controlled end of the first switch circuit 10 is used to receive a disconnection signal or a conduction signal;
[0042] Thermistor circuit 20;
[0043] a second switch circuit 30, wherein an input end of the second switch circuit 30 is electrically connected to an output end of the first switch circuit 10, a controlled end of the second switch circuit 30 is electrically connected to an output end of the second switch circuit 30, and an output end of the second switch circuit 30 is electrically connected to a first end of the thermistor circuit 20;
[0044] a third switch circuit 40 and a fourth switch circuit 50, wherein the input end of the third switch circuit 40 is electrically connected to the second end of the thermistor circuit 20, the input end of the fourth switch circuit 50 is used to access a power supply, the input end of the third switch circuit 40 is electrically connected to a controlled end of the fourth switch circuit 50, and the controlled end of the third switch circuit 40 is electrically connected to an output end of the fourth switch circuit 50;
[0045] A voltage divider circuit 80, wherein a first end of the voltage divider circuit 80 is electrically connected to an input end of the fourth switch circuit 50, the first end of the voltage divider circuit 80 is used to output a reference voltage, and the other end of the voltage divider circuit 80 is used to output a reference current;
[0046] The second switch circuit 30 is a depletion-type switch circuit, and the third switch circuit 40 is an enhancement-type switch circuit.
[0047] In this embodiment, the first switch circuit 10 and the fourth switch circuit 50 can be implemented by using at least one switch tube, such as a MOS tube, an IGBT tube, a thyristor, a triode, a power tube, etc.
[0048] In this embodiment, the second switch circuit 30 can be implemented by at least one depletion-type switch tube, and the third switch circuit 40 can be implemented by at least one enhancement-type switch tube. The number of switches used can be determined according to actual needs and is not limited here.
[0049] In this embodiment, the thermistor circuit 20 may be implemented by using at least one thermistor with a negative temperature coefficient or a positive temperature coefficient. The number of the thermistors used may be determined according to actual needs and is not limited herein.
[0050] The technical solution of the utility model includes a first switch circuit 10, a thermistor circuit 20, a second switch circuit 30, a third switch circuit 40 and a fourth switch circuit 50. The first switch circuit 10 is turned off when receiving a disconnection signal and turned on when receiving a conduction signal, thereby starting or shutting down the circuit. Since the second switch circuit 30 is a depletion type switch tube and its controlled end is short-circuited with the output end, the second switch circuit 30 is in a normally open state. The voltage of the power supply is transmitted to the controlled end of the fourth switch circuit 50 through the first switch circuit 10 and the second switch circuit 30. The fourth switch circuit 50 is turned on. Since the controlled end of the third switch circuit 40 is electrically connected to the output end of the fourth switch circuit 50, the third switch circuit 40 is also turned on. Since the input end of the fourth switch circuit 50 is connected to the power supply, the power supply outputs a corresponding reference current IBIAS through the output end of the fourth switch circuit 50 and the voltage divider circuit 80. The first end of the voltage divider circuit 80 is used to output a reference voltage VREF, and the accuracy of the reference current and the reference voltage is associated with the voltage stability of the controlled end of the fourth switch circuit 50. With such a configuration, the user can adjust the equivalent resistance of the voltage divider circuit 80 according to actual needs, so as to output the required reference voltage or reference current. In practical applications, it is assumed that the second switch circuit 30 is a depletion-type switch circuit, so the threshold voltage of the second switch circuit 30 is a negative temperature coefficient and a negative value; since the third switch circuit 40 is an enhancement-type switch circuit, the threshold voltage of the third switch circuit 40 is also a negative temperature coefficient and a positive value, then the input terminal voltage of the third switch circuit 40 is equal to the sum of the threshold voltage of the second switch circuit 30 and the threshold voltage of the third switch circuit 40. Since the threshold voltage of the second switch circuit 30 is a negative value, the input terminal voltage of the third switch circuit 40 is also equal to the threshold voltage of the third switch circuit 40. The difference between the absolute value of the threshold voltage of the second switch circuit 30 and the threshold voltage of the third switch circuit 40 is set in this way. In actual applications, when the ambient temperature rises or falls, the threshold voltage of the second switch circuit 30 and the threshold voltage of the third switch circuit 40 both decrease or increase. The user can adjust the width-to-length ratio of the second switch circuit 30 and the third switch circuit 40 according to the needs of the actual scene, so that the rate at which the threshold voltage of the second switch circuit 30 and the third switch circuit 40 change with temperature is closer or the amount of change is more matched, so that the difference, that is, the input terminal voltage of the third switch circuit 40 is not affected by temperature changes and remains basically unchanged, and the conduction degree of the fourth switch circuit 50 is also not affected by temperature, so its output reference voltage is a zero temperature coefficient voltage.In practical applications, due to process deviation, adjusting the width-to-length ratio of the switch circuit can effectively reduce the temperature drift of the threshold voltage, but it cannot completely eliminate it. For this reason, the process deviation can be further compensated by adjusting the temperature coefficient of the thermistor circuit 20. For example, when the negative temperature coefficient of the second switch circuit 30 is larger than the negative temperature coefficient of the third switch circuit 40, the negative deviation can be compensated by adjusting the temperature coefficient of the thermistor circuit 20 to a positive temperature coefficient. On the contrary, when the negative temperature coefficient of the second switch circuit 30 is smaller than the negative temperature coefficient of the third switch circuit 40, the positive deviation can be compensated by adjusting the temperature coefficient of the thermistor circuit 20 to a negative temperature coefficient. In this way, the voltage at the controlled end of the fourth switch circuit 50 is basically not affected by temperature, thereby obtaining a reference voltage value with the least temperature effect. In addition, the utility model only needs to use the temperature coefficient adjustment circuit of the first switch circuit 10, the second switch circuit 30 and the third switch circuit 40. Compared with the traditional temperature coefficient adjustment circuit, the utility model consumes less current and does not require components such as op amps, thereby avoiding the increase of power consumption and reducing the area occupancy of the overall circuit in the applied product.
[0051] refer to Figure 2 In one embodiment of the present utility model, the thermistor circuit 20 includes:
[0052] Thermistor R1, a first end of the thermistor R1 is electrically connected to the output end of the second switch circuit 30, a second end of the thermistor R1 is electrically connected to the input end of the third switch circuit 40, and a resistance value of the thermistor R1 decreases as the temperature rises, or a resistance value of the thermistor R1 increases as the temperature rises.
[0053] In this embodiment, the thermistor R1 with a negative temperature coefficient or a positive temperature coefficient is added to compensate for the deviation of the second switch circuit 30 and the third switch circuit 40 due to process errors, so that the reference voltage output by the fourth switch circuit 50 is not affected by temperature. The temperature coefficient of the thermistor R1 can be adjusted according to the actual situation of the circuit. With such a setting, in actual applications, when the negative temperature coefficient of the second switch circuit 30 is larger than the positive temperature coefficient of the third switch circuit 40, the user can adjust the thermistor R1 to a positive temperature coefficient to compensate for its negative deviation; when the negative temperature coefficient of the second switch circuit 30 is smaller than the positive temperature coefficient of the third switch circuit 40, the user can adjust the thermistor R1 to a negative temperature coefficient to compensate for its positive deviation. For the user, there is no need to adjust the sizes of the second switch circuit 30 and the third switch circuit 40 multiple times, and the deviation can be compensated only by adjusting or replacing the temperature coefficient of the thermistor R1, which is simple and convenient.
[0054] refer to Figure 2In one embodiment of the present utility model, the first switch circuit 10 includes:
[0055] The first switch tube Q1, the input end of the first switch tube Q1 is used to connect to the power supply, the controlled end of the first switch tube Q1 is used to receive a disconnection signal or a conduction signal, and the output end of the first switch tube Q1 is electrically connected to the input end of the second switch circuit 30.
[0056] In this embodiment, the first switch tube Q1 can be a transistor, a MOS tube or an IGPT tube.
[0057] In this embodiment, the first switch tube Q1 is a PMOS enabling tube. When the controlled end of the first switch tube Q1 receives a low-level signal, the first switch tube Q1 is turned on; when the controlled end of the first switch tube Q1 receives a high-level signal, the first switch tube Q1 is turned off. In this configuration, since the traditional bandgap reference has a complex circuit design, a startup circuit is required, and there are very strict requirements on the startup circuit, and the circuit design of the reference source circuit of the utility model is relatively simple, and it can be realized by using multiple switch tubes and multiple resistors. Therefore, the startup circuit of the utility model only needs one switch tube to be realized, and since the utility model needs to be used for a long time in actual applications, the power consumption can be reduced by using a low-level turn-on PMOS tube.
[0058] refer to Figure 2 In one embodiment of the present utility model, the second switch circuit 30 includes:
[0059] A second switch tube Q2, the input end of the second switch tube Q2 is electrically connected to the output end of the first switch circuit 10, the controlled end of the second switch tube Q2 is electrically connected to the output end of the second switch tube Q2, and the output end of the second switch tube Q2 is electrically connected to the input end of the third switch circuit 40; the second switch tube Q2 is a depletion type switch tube.
[0060] In this embodiment, the second switch tube Q2 is a depletion-type NMOS tube, the threshold voltage of the depletion-type NMOS tube is negative, and has a negative temperature coefficient, the gate and source of the depletion-type NMOS tube are short-circuited, and when UGS=0V, there is a conductive channel between the drain and source of the depletion-type NMOS tube, so no additional voltage is required to open the conductive channel, and the second switch tube Q2 is in a normally open state. With such a setting, compared with the traditional bandgap reference, the utility model does not need to use a large proportion of components such as triodes and operational amplifiers, and can directly use multiple switch tubes to achieve the effect that the reference voltage is basically not affected by temperature, and the second switch tube Q2 is in a normally open state, and there is no need to design a related startup circuit, thereby reducing the material cost and occupied area of the overall circuit.
[0061] refer to Figure 2In one embodiment of the present utility model, the third switch circuit 40 includes:
[0062] A third switch tube Q3, wherein the input end of the third switch tube Q3 is electrically connected to the second end of the thermistor circuit 20 and the controlled end of the fourth switch circuit 50 respectively, the controlled end of the third switch tube Q3 is electrically connected to the output end of the fourth switch circuit 50, and the output end of the third switch tube Q3 is grounded; the third switch tube Q3 is an enhanced switch tube.
[0063] In this embodiment, the third switch tube Q3 is an enhanced NMOS tube, the threshold voltage of the enhanced NMOS tube is positive, and has a negative temperature coefficient, the voltage at the input end of the third switch tube Q3 is equal to the sum of the threshold voltage of the third switch tube Q3 and the threshold voltage of the second switch circuit 30, and because the threshold voltage of the second switch circuit 30 is negative, the voltage at the input end of the third switch tube Q3 is also equal to the difference between the absolute value of the threshold voltage of the second switch circuit 30, so that in actual applications, the user can adjust the width-to-length ratio of the third switch tube Q3 and the second switch circuit 3 0, so that the rate of change of the threshold voltage of the second switch circuit and the third switch tube Q3 with temperature is closer or the amount of change is more matched, so that the voltage at the input end of the third switch tube Q3 is also equal to the difference of the absolute value of the threshold voltage of the second switch circuit 30, which is basically unchanged and not affected by temperature. Compared with the traditional bandgap reference, the utility model does not need to use a large proportion of components such as transistors and operational amplifiers, and can directly use multiple switch tubes to achieve the effect that the reference voltage is basically not affected by temperature, thereby reducing the material cost and occupied area of the overall circuit.
[0064] refer to Figure 2 In an embodiment of the utility model, the fourth switch circuit 50 includes a fourth switch tube Q4, the voltage divider circuit 80 includes a second resistor R2, the input end of the fourth switch tube Q4 is used to connect to the power supply, the controlled end of the fourth switch tube Q4 is electrically connected to the input end of the third switch circuit 40, the output end of the fourth switch tube Q4 is electrically connected to the controlled end of the third switch circuit 40 and the first end of the second resistor R2, and the second end of the second resistor R2 is grounded.
[0065] In the present embodiment, the fourth switch tube Q4 is an NMOS tube. Since the difference between the absolute value of the threshold voltage of the third switch circuit 40 and the absolute value of the threshold voltage of the second switch circuit 30 is not affected by temperature and remains substantially unchanged when the width-to-length ratio of the third switch circuit 40 and the width-to-length ratio of the second switch circuit 30 are within certain parameters, the voltage at the controlled end of the fourth switch tube Q4 is a zero temperature coefficient voltage, the conduction degree of the fourth switch tube Q4 remains substantially unchanged, the current outputted by the fourth switch tube Q4 is a zero temperature coefficient current, and the voltage (reference voltage) at the first end of the second resistor R2 is also a zero temperature coefficient voltage. With such a configuration, since the conduction degree of the fourth switch tube Q4 is substantially not affected by temperature, the current outputted by the fourth switch tube Q4 can be used as a reference current with a zero temperature coefficient, and the voltage of the second resistor R2 is a reference voltage with a zero temperature coefficient. In practical applications, the user can adjust the resistance value of the second resistor R2 according to actual needs to output the required reference voltage or reference current, which is simple and convenient.
[0066] refer to Figure 3 , the reference source circuit also includes:
[0067] A first current mirror circuit 60, wherein the first input terminal and the second input terminal of the first current mirror circuit 60 are both used to connect to a power supply, the first output terminal of the first current mirror circuit 60 is electrically connected to the input terminal of the fourth switch circuit 50, the controlled terminal of the first current mirror circuit 60 is electrically connected to the input terminal of the fourth switch circuit 50, and the second output terminal of the first current mirror circuit 60 is used to output a reference current.
[0068] In this embodiment, the first current mirror circuit 60 may be composed of a plurality of switch tubes.
[0069] In this embodiment, since the conduction degree of the fourth switch circuit 50 is not affected by temperature, the current output by the fourth switch circuit 50 is a zero temperature coefficient current and can be used as a reference current IBIAS, and the first current mirror circuit 60 is used to mirror the reference current so that the mirrored reference current is output from the second output terminal of the first current mirror circuit 60. In this arrangement, since the reference current has a zero temperature coefficient, the mirrored current output by the first current mirror circuit 60 will also have a zero temperature coefficient through the replication of the first current mirror circuit 60, thereby improving the temperature stability of the entire circuit, and can also conveniently provide a stable reference current for other circuit modules to meet a variety of different application requirements.
[0070] In this embodiment, the first current mirror circuit 60 includes:
[0071] a third resistor R3, a fifth switch tube Q5, a sixth switch tube Q6, a seventh switch tube Q7 and an eighth switch tube Q8, wherein the input end of the sixth switch tube Q6 is used to connect to a power supply, the output end of the sixth switch tube Q6 is electrically connected to the input end of the fifth switch tube Q5, the output end of the fifth switch tube Q5 is electrically connected to the first end of the third resistor R3, the second end of the third resistor R3 is electrically connected to the input end of the fourth switch circuit 50, the controlled end of the sixth switch tube Q6 is electrically connected to the first end of the third resistor R3, the controlled end of the fifth switch tube Q5 is electrically connected to the second end of the third resistor R3, the input end of the seventh switch tube Q7 is used to connect to a power supply, the controlled end of the seventh switch tube Q7 is electrically connected to the controlled end of the sixth switch tube Q6, the output end of the seventh switch tube Q7 is electrically connected to the input end of the eighth switch tube Q8, the controlled end of the eighth switch tube Q8 is electrically connected to the controlled end of the fifth switch tube Q5, and the output end of the eighth switch tube Q8 is used to output a reference current.
[0072] In this embodiment, the fifth switch tube Q5, the sixth switch tube Q6, the seventh switch tube Q7 and the eighth switch tube Q8 are all NMOS tubes and can form a self-biased current mirror architecture. Since the current mirrored by the biased current mirror architecture is determined by the fifth switch tube Q5 and the eighth switch tube Q8, the channel length of the fifth switch tube Q5 and the channel length of the eighth switch tube Q8 can be designed to be larger during the design process, so that the output impedance of the fifth switch tube Q5 and the eighth switch tube Q8 is large enough, thereby reducing the influence of their drain voltage and improving the accuracy of the mirror reference current.
[0073] In this embodiment, the reference source circuit also includes N second current mirror circuits 70, the input ends of the N second current mirror circuits 70 are used to connect to the power supply, the controlled end of the first second current mirror circuit 70 is electrically connected to the controlled end of the first current mirror circuit 60, the controlled end of the M+1th second current mirror circuit 70 is electrically connected to the controlled end of the Mth second current mirror circuit 70, and the output ends of the N second current mirror circuits 70 are used to output the reference current; wherein, 1<M<N.
[0074] In this embodiment, the second mirror circuit includes two NMOS tubes, wherein the input end of one of the NMOS tubes is used to connect to the power supply, the output end of one of the NMOS tubes is electrically connected to the input end of the other NMOS tube, the output end of the other NMOS tube is used to output a reference current, the gates of the two NMOS tubes of the M+1th second current mirror circuit 70 are electrically connected to the gates of the two NMOS tubes of the Mth second current mirror circuit 70, and the N second current mirror circuits 70 are used to copy the reference current output by the first current mirror circuit 60 and output N reference currents. With such a configuration, in practical applications, for example, in some complex electronic systems, multiple modules may work together to complete specific functions, and each module may require an independent reference current to ensure its normal operation and stable performance. The reference source circuit of the utility model can provide an independent reference current for each module by setting multiple second current mirror circuits 70, thereby ensuring that they can work together and meet the expected performance requirements.
[0075] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.
Claims
1. A reference source circuit, characterized in that: The reference source circuit comprises: a first switch circuit, wherein an input end of the first switch circuit is used to connect to a power supply, and a controlled end of the first switch circuit is used to receive a disconnection signal or a conduction signal; Thermal circuit; a second switch circuit, wherein an input end of the second switch circuit is electrically connected to an output end of the first switch circuit, a controlled end of the second switch circuit is electrically connected to an output end of the second switch circuit, and an output end of the second switch circuit is electrically connected to a first end of the thermistor circuit; a third switch circuit and a fourth switch circuit, wherein the input end of the third switch circuit is electrically connected to the second end of the thermistor circuit, the input end of the fourth switch circuit is used to access a power supply, the input end of the third switch circuit is electrically connected to a controlled end of the fourth switch circuit, and the controlled end of the third switch circuit is electrically connected to an output end of the fourth switch circuit; A voltage divider circuit, wherein a first end of the voltage divider circuit is electrically connected to an output end of the fourth switch circuit, the first end of the voltage divider circuit is used to output a reference voltage, and the other end of the voltage divider circuit is used to output a reference current; Among them, the second switch circuit is a depletion-type switch circuit, and the third switch circuit is an enhancement-type switch circuit.
2. The reference source circuit according to claim 1, characterized in that: The thermal circuit comprises: A thermistor, wherein a first end of the thermistor is electrically connected to the output end of the second switch circuit, and a second end of the thermistor is electrically connected to the input end of the third switch circuit.
3. The reference source circuit according to claim 1, characterized in that: The first switch circuit comprises: A first switch tube, wherein the input end of the first switch tube is used to connect to a power supply, the controlled end of the first switch tube is used to receive a disconnection signal or a conduction signal, and the output end of the first switch tube is electrically connected to the input end of the second switch circuit.
4. The reference source circuit according to claim 1, characterized in that: The second switch circuit comprises: A second switch tube, the input end of the second switch tube is electrically connected to the output end of the first switch circuit, the controlled end of the second switch tube is electrically connected to the output end of the second switch tube, and the output end of the second switch tube is electrically connected to the input end of the third switch circuit; the second switch tube is a depletion type switch tube.
5. The reference source circuit according to claim 1, characterized in that: The third switch circuit comprises: A third switch tube, wherein the input end of the third switch tube is electrically connected to the second end of the thermistor circuit and the controlled end of the fourth switch circuit respectively, the controlled end of the third switch tube is electrically connected to the output end of the fourth switch circuit, and the output end of the third switch tube is grounded; the third switch tube is an enhanced switch tube.
6. The reference source circuit according to claim 1, characterized in that: The fourth switch circuit includes a fourth switch tube, the voltage divider circuit includes a second resistor, the input end of the fourth switch tube is used to connect to the power supply, the controlled end of the fourth switch tube is electrically connected to the input end of the third switch circuit, the output end of the fourth switch tube is electrically connected to the controlled end of the third switch circuit and the first end of the second resistor respectively, and the second end of the second resistor is grounded.
7. The reference source circuit according to claim 1, characterized in that: The reference source circuit also includes: A first current mirror circuit, wherein the first input terminal and the second input terminal of the first current mirror circuit are both used to connect to a power supply, the first output terminal of the first current mirror circuit is electrically connected to the input terminal of the fourth switch circuit, the controlled terminal of the first current mirror circuit is electrically connected to the input terminal of the fourth switch circuit, and the second output terminal of the first current mirror circuit is used to output a reference current.
8. The reference source circuit as claimed in claim 7, characterized in that: The first current mirror circuit comprises: a third resistor, a fifth switch tube, a sixth switch tube, a seventh switch tube and an eighth switch tube, wherein the input end of the sixth switch tube is used to connect to a power supply, the output end of the sixth switch tube is electrically connected to the input end of the fifth switch tube, the output end of the fifth switch tube is electrically connected to the first end of the third resistor, the second end of the third resistor is electrically connected to the input end of the fourth switch circuit, the controlled end of the sixth switch tube is electrically connected to the first end of the third resistor, the controlled end of the fifth switch tube is electrically connected to the second end of the third resistor, the input end of the seventh switch tube is used to connect to a power supply, the controlled end of the seventh switch tube is electrically connected to the controlled end of the sixth switch tube, the output end of the seventh switch tube is electrically connected to the input end of the eighth switch tube, the controlled end of the eighth switch tube is electrically connected to the controlled end of the fifth switch tube, and the output end of the eighth switch tube is used to output a reference current.
9. The reference source circuit according to claim 7, characterized in that: The reference source circuit also includes N second current mirror circuits, the input ends of the N second current mirror circuits are used to connect to the power supply, the controlled end of the first second current mirror circuit is electrically connected to the controlled end of the first current mirror circuit, the controlled end of the M+1th second current mirror circuit is electrically connected to the controlled end of the Mth second current mirror circuit, and the output ends of the N second current mirror circuits are used to output a reference current; wherein, 1<M<N.