Band-gap reference circuit and electronic device

Abstract

The invention provides a band-gap reference circuit and electronic equipment, and belongs to the technical field of power electronics. The band-gap reference circuit includes a current generating circuit and a voltage generating circuit. The voltage generation circuit can generate the first band-gap reference voltage based on the positive temperature coefficient current generated by the current generation circuit, and then performs secondary voltage reduction processing on the generated first band-gap reference voltage to generate the second band-gap reference voltage, so that the voltage reduction processing mode can be flexibly set; therefore, the voltage generation circuit can flexibly generate expected small band-gap reference voltage which is basically not changed along with temperature according to actual requirements, the requirements of different circuits are well met, and the band-gap reference circuit is good in working flexibility.

Description

Technical Field

[0001] The present application relates to the field of power electronics technology, and in particular to a bandgap reference circuit and electronic equipment. Background Art

[0002] A bandgap reference circuit is a circuit that can generate a bandgap reference voltage that is basically unchanged with temperature. It is mostly used to provide the required reference voltage to circuits such as operational amplifiers, linear voltage regulators or reference current sources.

[0003] However, due to structural limitations and other factors, traditional bandgap reference circuits can only generate a bandgap reference voltage of a fixed size, and the generated bandgap reference voltage is generally large and has poor working flexibility. Summary of the invention

[0004] The embodiment of the present application provides a bandgap reference circuit and an electronic device, which can solve the problem of poor working flexibility of the bandgap reference circuit in the related art. The technical solution is as follows:

[0005] In one aspect, a bandgap reference circuit is provided, the bandgap reference circuit comprising: a current generating circuit and a voltage generating circuit; the current generating circuit is connected to the voltage generating circuit;

[0006] The current generating circuit is used to: generate a positive temperature coefficient current;

[0007] The voltage generating circuit is used for generating a first bandgap reference voltage based on the positive temperature coefficient current, and performing a voltage reduction process on the first bandgap reference voltage to generate a second bandgap reference voltage.

[0008] Optionally, the voltage reduction process includes: voltage division process; the voltage generating circuit includes: a voltage generating subcircuit and a voltage dividing subcircuit; the voltage generating subcircuit is connected to the current generating circuit and the voltage dividing subcircuit respectively;

[0009] The voltage generating subcircuit and the voltage dividing subcircuit are used to: generate the first bandgap reference voltage based on the positive temperature coefficient current;

[0010] The voltage division subcircuit is further used for: performing voltage division processing on the first bandgap reference voltage to generate the second bandgap reference voltage.

[0011] Optionally, the voltage divider subcircuit includes: at least two first resistors;

[0012] The at least two first resistors are sequentially connected in series, with one end of the series connection connected to the voltage generating subcircuit and the other end of the series connection being grounded, wherein at least one series node is used to output the second bandgap reference voltage.

[0013] Optionally, the voltage generating subcircuit comprises: a current mirror unit and a voltage generating unit; the current mirror unit is connected to the current generating circuit and the voltage generating unit respectively, and the voltage generating unit is also connected to the voltage dividing subcircuit;

[0014] The current mirror unit is used to: output the positive temperature coefficient current mirror image to the voltage generating unit;

[0015] The voltage generating unit and the voltage dividing sub-circuit are used to generate the first bandgap reference voltage based on the positive temperature coefficient current output by the current mirror unit.

[0016] Optionally, the current mirror unit includes: a first transistor and a second transistor; the voltage generating unit includes: a second resistor, a third resistor and a triode;

[0017] The gate of the first transistor and the gate of the second transistor are both connected to the current generating circuit, the source of the first transistor is connected to the power supply terminal, the drain of the first transistor is connected to the source of the second transistor, the drain of the second transistor is connected to one end of the second resistor, the other end of the second resistor is connected to one end of the third resistor, the other end of the third resistor is connected to the emitter of the transistor, and the base and collector of the transistor are both grounded; and the voltage divider subcircuit is connected to the connection point of the second resistor and the third resistor.

[0018] Optionally, the bandgap reference circuit further includes: a self-starting circuit; the self-starting circuit is connected to the current generating circuit;

[0019] The self-starting circuit is used to: receive a first control signal, and output a start control signal to the current generating circuit based on the first control signal;

[0020] The current generating circuit is used for generating the positive temperature coefficient current in response to the start control signal.

[0021] Optionally, the self-starting circuit comprises: a first control subcircuit, a second control subcircuit and a charge-discharge electronic circuit; the first control subcircuit is respectively connected to a power supply terminal, a ground terminal and a control node, the second control subcircuit is respectively connected to the control node, the power supply terminal and the current generating circuit, and the charge-discharge electronic circuit is connected between the control node and the ground terminal;

[0022] The first control subcircuit is used to: receive the first control signal, and in response to the first control signal, control the connection and disconnection between the power supply terminal and the control node, control the connection and disconnection between the ground terminal and the control node, and adjust the potential of the control node by charging and discharging the charge-discharge electronic circuit;

[0023] The second control subcircuit is used to receive the first control signal, and in response to the first control signal and the potential of the control node, control the connection and disconnection between the power supply terminal and the current generating circuit to output the start control signal to the current generating circuit.

[0024] Optionally, the first control subcircuit includes: a third transistor and a fourth transistor;

[0025] The gate of the third transistor is used to receive the first control signal, the source of the third transistor is connected to the power supply terminal, and the drain of the third transistor is connected to the control node;

[0026] The gate of the fourth transistor is used to receive the first control signal, the source of the fourth transistor is connected to the ground terminal, and the drain of the fourth transistor is connected to the control node.

[0027] Optionally, the second control subcircuit includes: a fifth transistor and a sixth transistor;

[0028] The gate of the fifth transistor is used to receive the first control signal, the source of the fifth transistor is connected to the power supply terminal, the drain of the fifth transistor is connected to the source of the sixth transistor, the gate of the sixth transistor is connected to the control node, and the drain of the sixth transistor is connected to the current generating circuit.

[0029] Optionally, the charging and discharging electronic circuit comprises: a seventh transistor;

[0030] A gate of the seventh transistor is connected to the control node, and a source and a drain of the seventh transistor are connected to the ground terminal.

[0031] Optionally, the bandgap reference circuit further includes: a switch control circuit; the switch control circuit is connected to the self-starting circuit;

[0032] The switch control circuit is used to output the first control signal to the self-starting circuit.

[0033] Optionally, the switch control circuit is also connected to the current generating circuit;

[0034] The switch control circuit is further used to: output a second control signal to the current generating circuit;

[0035] The current generating circuit is used for generating the positive temperature coefficient current in response to the start control signal and the second control signal.

[0036] Optionally, the switch control circuit is used to: receive an enable signal, and generate the first control signal and the second control signal based on the enable signal.

[0037] Optionally, in the same period, the potential of the second control signal is opposite to the potential of the first control signal; the switch control circuit comprises: a first inverter and a second inverter;

[0038] The input end of the first inverter is used to receive the enable signal, the output end of the first inverter is connected to the input end of the self-starting circuit and the second inverter respectively, and the output end of the second inverter is connected to the current generating circuit.

[0039] Optionally, the first inverter and the second inverter both include: a complementary metal oxide semiconductor field effect transistor connected between a power supply terminal and a ground terminal.

[0040] Optionally, the current generating circuit is a current generating circuit with a self-bias structure.

[0041] In another aspect, an electronic device is provided, the electronic device comprising: a load, and the bandgap reference circuit as described in the above aspect;

[0042] Wherein, the bandgap reference circuit is connected to the load and is used to output a bandgap reference voltage to the load.

[0043] In summary, the technical solution provided by the embodiments of the present application brings at least the following beneficial effects:

[0044] A bandgap reference circuit and an electronic device are provided. The bandgap reference circuit includes a current generating circuit and a voltage generating circuit. Since the voltage generating circuit can first generate a first bandgap reference voltage based on a positive temperature coefficient current generated by the current generating circuit, and then perform a secondary voltage reduction process on the generated first bandgap reference voltage to generate a second bandgap reference voltage, it can be seen that the voltage reduction process can be flexibly set so that the voltage generating circuit can flexibly generate a desired smaller bandgap reference voltage that is substantially invariant to temperature according to actual needs, thereby better meeting the needs of different circuits, and the bandgap reference circuit has good working flexibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0046] Figure 1is a schematic structural diagram of a bandgap reference circuit provided in an embodiment of the present application;

[0047] Figure 2 is a schematic diagram of a voltage generating circuit provided in an embodiment of the present application;

[0048] Figure 3 is a structural schematic diagram of another voltage generating circuit provided in an embodiment of the present application;

[0049] Figure 4 is a circuit structure diagram of a voltage generating circuit provided in an embodiment of the present application;

[0050] Figure 5 is a circuit structure schematic diagram of another voltage generating circuit provided in an embodiment of the present application;

[0051] Figure 6 is a schematic structural diagram of another bandgap reference circuit provided in an embodiment of the present application;

[0052] Figure 7 It is a structural schematic diagram of a self-starting circuit provided in an embodiment of the present application;

[0053] Figure 8 It is a circuit structure schematic diagram of a self-starting circuit provided in an embodiment of the present application;

[0054] Fig. 9 is a structural schematic diagram of another bandgap reference circuit provided in an embodiment of the present application;

[0055] Fig.10 is a circuit structure diagram of a switch control circuit provided in an embodiment of the present application;

[0056] Fig.11 is a circuit structure schematic diagram of a current generating circuit provided in an embodiment of the present application;

[0057] Fig.12 1 is a schematic diagram of a circuit structure of a bandgap reference circuit provided in an embodiment of the present application;

[0058] Fig.13 It is a structural schematic diagram of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0059] In order to make the objectives, technical solutions and advantages of the present application clearer, the implementation methods of the present application will be further described in detail below with reference to the accompanying drawings.

[0060] The embodiment of the present application provides a bandgap reference circuit that can generate and output a lower bandgap reference voltage lower than 1V, and can flexibly adjust the output voltage as needed. At the same time, it can also flexibly output multiple different bandgap reference voltages to meet the complex needs of various circuits.

[0061] Figure 1 Schematic diagram of the structure of the bandgap reference circuit provided by the embodiment of the present application. Figure 1 As shown, the bandgap reference circuit 00 includes: a current generating circuit 01 and a voltage generating circuit 02. The current generating circuit 01 is connected to the voltage generating circuit 02.

[0062] The current generating circuit 01 is used to generate a positive temperature coefficient current.

[0063] The voltage generating circuit 02 is used to generate a first bandgap reference voltage based on a positive temperature coefficient current, and to perform a voltage reduction process on the first bandgap reference voltage to generate a second bandgap reference voltage. It is understandable that, through the voltage reduction process, the voltage generating circuit 02 can ultimately generate a second bandgap reference voltage that is smaller than the first bandgap reference voltage.

[0064] Among them, the positive temperature coefficient current is also a current that is proportional to absolute temperature (PTAT), also known as PTAT current. Proportional can mean that the higher the temperature, the larger the PTAT current; conversely, the lower the temperature, the smaller the PTAT current. When the voltage generating circuit 02 generates a bandgap reference voltage based on the PTAT current, it can compensate the positive temperature coefficient by a negative temperature coefficient to generate a voltage that does not change with temperature. Generally, the bandgap reference voltage (i.e., the first bandgap reference voltage) generated by the voltage generating circuit 02 based on the PTAT current is about 1V. In the embodiment of the present application, since the voltage generating circuit 02 will also step down the first bandgap reference voltage after generating the first bandgap reference voltage based on the PTAT current, it is possible to flexibly set the step-down processing method to finally generate and output a bandgap reference voltage less than 1V (i.e., the second bandgap reference voltage).

[0065] That is, in the embodiment of the present application, combined with Figure 1 The bandgap reference voltage finally generated by the bandgap reference circuit 00 and output to other loads (eg, a linear voltage regulator) via the output terminal VOUT may be a second bandgap reference voltage less than 1V.

[0066] In summary, an embodiment of the present application provides a bandgap reference circuit. The bandgap reference circuit includes a current generating circuit and a voltage generating circuit. Since the voltage generating circuit can first generate a first bandgap reference voltage based on the positive temperature coefficient current generated by the current generating circuit, and then perform a secondary voltage reduction process on the generated first bandgap reference voltage to generate a second bandgap reference voltage, it can be seen that the voltage reduction process can be flexibly set so that the voltage generating circuit can flexibly generate a desired smaller bandgap reference voltage that is basically not affected by temperature according to actual needs, thereby better meeting the needs of different circuits, and the working flexibility of the bandgap reference circuit is better.

[0067] Optionally, the voltage reduction process may include: voltage division process. That is, the voltage generating circuit 02 may perform voltage division process on the first bandgap reference voltage generated based on the positive temperature coefficient current to generate a second bandgap reference voltage smaller than the first bandgap reference voltage. On this basis, Figure 2 FIG. 2 shows a schematic diagram of the structure of a voltage generating circuit 02. Figure 2 As shown, the voltage generating circuit 02 may include: a voltage generating subcircuit 021 and a voltage dividing subcircuit 022. The voltage generating subcircuit 021 may be connected to the current generating circuit 01 (not shown in the figure) and the voltage dividing subcircuit 022, respectively.

[0068] The voltage generating subcircuit 021 and the voltage dividing subcircuit 022 can be used to generate a first bandgap reference voltage based on a positive temperature coefficient current.

[0069] The voltage divider subcircuit 022 may also be used to perform voltage division processing on the first bandgap reference voltage to generate a second bandgap reference voltage.

[0070] That is, first, the voltage generating subcircuit 021 and the voltage dividing subcircuit 022 can cooperate with each other to generate a first bandgap reference voltage that does not substantially change with temperature based on the PTAT current that changes with temperature, and then the voltage dividing subcircuit 022 divides the first bandgap reference voltage to generate a second bandgap reference voltage that is smaller than the first bandgap reference voltage, thereby achieving the purpose of voltage reduction.

[0071] Optionally, in Figure 2 On the basis of Figure 3 FIG. 2 shows a schematic diagram of another voltage generating circuit 02. Figure 3 As shown, the voltage generating subcircuit 021 may include: a current mirror unit 0211 and a voltage generating unit 0212. The current mirror unit 0211 may be connected to the current generating circuit 01 (not shown) and the voltage generating unit 0212 respectively, and the voltage generating unit 0212 may also be connected to the voltage dividing subcircuit 022.

[0072] The current mirror unit 0211 can be used to output the positive temperature coefficient current mirror image to the voltage generating unit 0212 .

[0073] The voltage generating unit 0212 and the voltage dividing sub-circuit 022 can be used to generate a first bandgap reference voltage based on the positive temperature coefficient current output by the current mirror unit 0211 .

[0074] That is, first, the current mirror unit 0211 can use the current mirror function to output the temperature-varying PTAT current mirror image generated by the current generating circuit 01 to the voltage generating unit 0212, and then the voltage generating unit 0212 and the voltage divider subcircuit 022 cooperate with each other to generate a first bandgap reference voltage that does not vary substantially with temperature based on the received PTAT current.

[0075] Optionally, in Figure 3 On the basis of Figure 4 FIG. 2 shows a schematic diagram of a circuit structure of a voltage generating circuit 02. Figure 4 As shown, the voltage divider subcircuit 022 may include: at least two first resistors R1.

[0076] The at least two first resistors R1 are connected in series in sequence, and one end of the series connection is connected to the voltage generating sub-circuit 021, and the other end of the series connection is grounded, that is, connected to the ground terminal GND, wherein at least one series connection node is used to output the second bandgap reference voltage. That is, at least two first resistors R1 can be used as voltage dividing resistors to implement voltage dividing processing of the first bandgap reference voltage.

[0077] It is understandable that, combined with Figure 4 , one end and the other end of the series connection may refer to the head end and the tail end of at least two first resistors R1 connected in series in sequence, respectively. At least one series node may refer to the series node of each adjacent two first resistors R1 in at least two first resistors R1 connected in series in sequence. One (or one) second bandgap reference voltage can be output by voltage division through one series node, and then multiple (or multiple) second bandgap reference voltages can be output by voltage division through multiple series nodes. That is, the number of second bandgap reference voltages generated by the voltage divider subcircuit 022 may be equal to the number of series nodes possessed by the voltage divider subcircuit 022.

[0078] For example, refer to Figure 4 , the voltage divider subcircuit 022 shown therein includes two first resistors R1 connected in series, which are marked as R1-1 and R1-2 for distinction. The two first resistors R1-1 and R1-2 have a series node S1. Under the voltage division process of the two first resistors R1-1 and R1-2, the voltage divider subcircuit 022 can output a second bandgap reference voltage through the series node S1.

[0079] For example, refer to Figure 5 , the voltage divider subcircuit 022 shown therein includes four first resistors R1 connected in series in sequence, which are respectively marked as R1-1, R1-2, R1-3 and R1-4 for distinction. The four first resistors R1-1 to R1-4 have three series nodes S1, S2 and S3. Under the voltage division process of the four first resistors R1-1 to R1-4, the voltage divider subcircuit 022 can output three second bandgap reference voltages through the three series nodes S1 to S3.

[0080] Combination Figure 4 and Figure 5 It can be seen that in the embodiment of the present application, the resistance ratio of each two adjacent first resistors R1 can be flexibly adjusted to generate any desired second bandgap reference voltage lower than 1V. In addition, the number of first resistors R1 can be flexibly set to obtain any desired multiple second bandgap reference voltages lower than 1V.

[0081] Optionally, continue to refer to Figure 5 It can be seen that the current mirror unit 0211 may include: a first transistor M1 and a second transistor M2. The voltage generating unit 0212 may include: a second resistor R2, a third resistor R3 and a transistor T1.

[0082] The gate of the first transistor M1 and the gate of the second transistor M2 can be connected to the current generating circuit 01, the source of the first transistor M1 can be connected to the power supply terminal VDD, the drain of the first transistor M1 can be connected to the source of the second transistor M2, the drain of the second transistor M2 can be connected to one end of the second resistor R2, the other end of the second resistor R2 can be connected to one end of the third resistor R3, the other end of the third resistor R3 can be connected to the emitter of the transistor T1, and the base and collector of the transistor T1 can be grounded, that is, connected to the ground terminal GND.

[0083] Furthermore, the voltage divider subcircuit 022 may be connected to a connection point P0 between the second resistor R2 and the third resistor R3. That is, at least two first resistors R1 included in the voltage divider subcircuit 022 may be connected in series between the connection point P0 and the ground terminal GND.

[0084] Understandably, Figure 4 and Figure 5 The current generating circuit 01 is not shown, and V1 indicates that the gate of the first transistor M1 is connected to the current generating circuit 01, V2 indicates that the gate of the second transistor M2 is connected to the current generating circuit 01, and V3 indicates the second bandgap reference voltage output through the output terminal VOUT. Figure 5 On the basis of setting four first resistors R1 - 1 to R1 - 4 , three second bandgap reference voltages V3 - 1 , V3 - 2 and V3 - 3 can be output.

[0085] It can also be understood that the potential of the power signal provided by the power terminal VDD is generally a high potential, and the potential of the signal provided by the ground terminal GND is generally a low potential. Of course, the high potential and low potential here are relative.

[0086] Optionally, continue to refer to Figure 4 and Figure 5 It can also be seen that the transistors shown are all P-type transistors, and the triodes shown are PNP-type transistors.

[0087] And, combined with Figure 4 and Figure 5 It can be seen that in the embodiment of the present application, the mirror current of the PTAT current generated by the current generating circuit 01 can be obtained by the current mirror formed by the first transistor M1 and the second transistor M2. The PTAT current flows through the second resistor R2, the third resistor R3, multiple first resistors R1 and the transistor T1, and can be compensated with the negative temperature coefficient of the transistor T1, thereby obtaining a bandgap reference voltage that does not change with temperature. The resistance values ​​of each resistor can be flexibly adjusted so that a first bandgap reference voltage of about 1V (e.g., 0.9V) is generated at the common node (i.e., connection point P0) of the second resistor R2, the third resistor R3 and multiple first resistors R1. After that, through the voltage division process of multiple first resistors R1, a second bandgap reference voltage lower than 1V (e.g., 0.5V) that is smaller than the first bandgap reference voltage can be generated.

[0088] Optionally, in Figure 1 On the basis of Figure 6 FIG. 2 shows a schematic diagram of the structure of another bandgap reference circuit. Figure 6 As shown, the bandgap reference circuit may further include: a self-starting circuit 03. The self-starting circuit 03 may be connected to the current generating circuit 01.

[0089] The self-starting circuit 03 can be used to receive a first control signal VC, and output a start control signal VO to the current generating circuit 01 based on the first control signal.

[0090] The current generating circuit 01 can be used to generate a positive temperature coefficient current in response to a start control signal VO.

[0091] That is, the self-starting circuit 03 can be set to output a starting control signal to the current generating circuit 01, so that the current generating circuit 01 can reliably start in response to the starting control signal to enter a normal working state, thereby ensuring that the current generating circuit 01 can enter a normal working state to reliably generate a PTAT current during the power-on process.

[0092] For example, when the potential of the first control signal VC is the first potential, the self-starting circuit 03 can output a start control signal to the current generating circuit 01, so that the current generating circuit 01 is turned on and works. When the potential of the first control signal VC is the second potential, the self-starting circuit 03 can stop outputting the start control signal to the current generating circuit 01. And, generally, when the bandgap reference circuit is started (i.e., power on), the potential of the first control signal can be the first potential; when the bandgap reference circuit is turned off (i.e., power down), the potential of the first control signal can be the second potential.

[0093] Optionally, the first potential may be an effective potential, and the second potential may be an invalid potential. Moreover, for a P-type transistor, the effective potential may be a low potential relative to the invalid potential; for an N-type transistor, the effective potential may be a high potential relative to the invalid potential.

[0094] Optionally, in Figure 6 On the basis of Figure 7 FIG. 2 shows a schematic diagram of the structure of a self-starting circuit 03. Figure 7 As shown, the self-starting circuit 03 includes: a first control subcircuit 031, a second control subcircuit 032 and a charge-discharge electronic circuit 033. The first control subcircuit 031 can be connected to the power supply terminal VDD, the ground terminal GND and the control node N0 respectively, the second control subcircuit 032 can be connected to the control node N0, the power supply terminal VDD and the current generating circuit 01 respectively, and the charge-discharge electronic circuit 033 can be connected between the control node N0 and the ground terminal GND. Figure 7 The current generating circuit 01 is not shown.

[0095] The first control subcircuit 031 can be used to: receive a first control signal VC, and in response to the first control signal VC, control the connection and disconnection between the power supply terminal VDD and the control node N0, control the connection and disconnection between the ground terminal GND and the control node N0, and adjust the potential of the control node N0 by charging and discharging the charge and discharge electronic circuit 033.

[0096] For example, when the potential of the first control signal VC is the first potential, the first control subcircuit 031 can control the power supply terminal VDD to be turned on and the control node N0 to be disconnected, and the ground terminal GND to be disconnected from the control node N0, and the power supply terminal VDD to form a path with the ground terminal GND through the charging and discharging electronic circuit 033 to charge the charging and discharging electronic circuit 033, and finally adjust the potential of the control node N0 from the initial low potential to gradually increase to a high potential; and when the potential of the first control signal VC is the second potential, the power supply terminal VDD can be disconnected from the control node N0, and the ground terminal GND to be turned on and the charge stored in the charging and discharging electronic circuit 033 can be discharged to the ground, and the charging and discharging electronic circuit 033 starts to discharge, and finally adjusts the potential of the control node N0 from the high potential to gradually recover to the low potential. It can also be seen that in the first control subcircuit 031, the transistor that controls the connection between the power supply terminal VDD and the control node N0 and the transistor that controls the connection between the ground terminal GND and the control node N0 can be of different types, that is, one can be a P-type transistor and the other can be an N-type transistor.

[0097] The second control subcircuit 032 can be used to receive the first control signal VC, and in response to the first control signal VC and the potential of the control node N0, control the connection between the power supply terminal VDD and the current generating circuit 01 to output a start control signal VO to the current generating circuit 01.

[0098] For example, the second control subcircuit 032 can control the power supply terminal VDD to be connected with the current generating circuit 01 when the potential of the first control signal VC and the potential of the control node N0 are both at the first potential, so as to output the start control signal VO to the current generating circuit 01; and can control the power supply terminal VDD to be disconnected from the current generating circuit 01 when the potential of the first control signal VC and / or the potential of the control node N0 are at the second potential, so as to stop outputting the start control signal VO to the current generating circuit 01. It can also be known that the transistors included in the second control subcircuit 032 can be of the same type, that is, they can all be P-type transistors or N-type transistors.

[0099] Optionally, in Figure 7 On the basis of Figure 8 FIG. 2 shows a circuit structure diagram of a self-starting circuit 03. Figure 8 As shown, the first control subcircuit 031 may include: a third transistor M3 and a fourth transistor M4. In addition, in combination with the above description, reference Figure 8 , the third transistor M3 shown therein is a P-type transistor, and the fourth transistor M4 is an N-type transistor.

[0100] The gate of the third transistor M3 may be used to receive the first control signal VC, the source of the third transistor M3 may be connected to the power supply terminal VDD, and the drain of the third transistor M3 is connected to the control node N0.

[0101] A gate of the fourth transistor M4 may be configured to receive the first control signal VC, a source of the fourth transistor M4 may be connected to the ground terminal GND, and a drain of the fourth transistor M4 may be connected to the control node N0.

[0102] Optionally, continue to refer to Figure 8 It can be seen that the second control subcircuit 032 may include: a fifth transistor M5 and a sixth transistor M6. Figure 8 , the fifth transistor M5 and the sixth transistor M6 shown therein are both P-type transistors.

[0103] The gate of the fifth transistor M5 can be used to receive the first control signal VC, the source of the fifth transistor M5 can be connected to the power supply terminal VDD, the drain of the fifth transistor M5 can be connected to the source of the sixth transistor M6, the gate of the sixth transistor M6 can be connected to the control node N0, and the drain of the sixth transistor M6 can be connected to the current generating circuit 01. Figure 8 The current generating circuit 01 is not shown either, but the start control signal VO output to the current generating circuit 01 is schematically shown. Figure 8 As shown, the start control signal VO can be outputted through the drain of the sixth transistor M6.

[0104] Optionally, continue to refer to Figure 8 It can be seen that the charging and discharging electronic circuit 033 may include: a seventh transistor M7.

[0105] The gate of the seventh transistor M7 can be connected to the control node N0, and the source and drain of the seventh transistor M7 can be connected to the ground terminal GND. That is, a transistor can be used to form a capacitor to realize charging and discharging. Of course, in some other embodiments, the seventh transistor M7 can also be replaced by a capacitor.

[0106] And, combined with Figure 8 It can be seen that in the embodiment of the present application, the self-starting circuit 03 can charge and discharge the node capacitance (such as the capacitance formed by the seventh transistor M7) to force the node potential to be pulled up or down, thereby achieving the purpose of self-starting, so as to solve the problem that the bandgap reference circuit cannot be started normally after power-on. That is, it is ensured that the bandgap reference circuit can be started normally.

[0107] by Figure 8Taking the structure shown as an example, combined with the above records, it can be known that the initial potential of the control node N0 is generally a low potential, and accordingly, the P-type sixth transistor M6 can be turned on. Then, when the bandgap reference circuit is started (i.e., power on), the potential of the first control signal VC can be a low potential. In this way, the P-type third transistor M3 and the P-type fifth transistor M5 can be turned on, and the N-type fourth transistor M4 can be turned off. Furthermore, the power supply terminal VDD and the control node N0 and the current generating circuit 01 can be turned on, and the current can pull up the internal node potential of the current generating circuit 01 through the turned-on fifth transistor M5 and the sixth transistor M6, that is, the start control signal VO can be output to the current generating circuit 01, the current generating circuit 01 is turned on, and the control current generating circuit 01 is started. At the same time, the current can also charge the seventh transistor M7 as a capacitor through the turned-on third transistor M3 to pull up the potential of the gate of the P-type sixth transistor M6 (i.e., the control node N0) until the P-type sixth transistor M6 is turned off, and the self-starting circuit 03 completes the startup function. When the bandgap reference circuit is turned off (i.e., powerdown), the potential of the first control signal VC can be changed from a low potential to a high potential. In this way, the P-type third transistor M3 and the P-type fifth transistor M5 can be turned off, and the N-type fourth transistor M4 can be turned on. In addition, the charge stored in the seventh transistor M7 as a capacitor can be discharged to the ground through the turned-on fourth transistor M4, and the potential of the gate of the P-type sixth transistor M6 (i.e., the control node N0) is gradually reduced again, and finally the P-type sixth transistor M6 is turned on to prepare for the next startup.

[0108] Optionally, in Figure 6 On the basis of Fig. 9 FIG. 2 shows a schematic diagram of the structure of another bandgap reference circuit. Fig. 9 As shown, the bandgap reference circuit may further include: a switch control circuit 04. The switch control circuit 04 may be connected to the self-starting circuit 03.

[0109] The switch control circuit 04 can be used to output a first control signal VC to the self-starting circuit 03. That is, a switch control circuit 04 can be set to flexibly output a first control signal VC of a desired potential to the self-starting circuit 03. Figure 8 It can also be known that the switch control circuit 04 can be connected to the gate of the third transistor M3 , the gate of the fourth transistor M4 , and the gate of the fifth transistor M5 in the self-starting circuit 03 .

[0110] Optionally, continue to refer to Fig. 9 It can be seen that, in some embodiments, the switch control circuit 04 may also be connected to the current generating circuit 01 .

[0111] The switch control circuit 04 may also be configured to output a second control signal VG to the current generating circuit 01 .

[0112] The current generating circuit 01 can be used to generate a positive temperature coefficient current in response to a start control signal VO and a second control signal VG.

[0113] That is, the switch control circuit 04 may be configured to flexibly output a second control signal VG of a required potential to the current generating circuit 01, so as to further reliably ensure the normal startup and operation of the current generating circuit 01. For example, the current generating circuit 01 may be started and generate the PTAT current when the startup control signal VO is received and the potential of the second control signal VG is a valid potential (e.g., a low potential).

[0114] Optionally, in some other embodiments, continue to refer to Fig. 9 It can be seen that the switch control circuit 04 can also be connected to the voltage generating circuit 02 and used to output a control signal to the voltage generating circuit 02 to control the voltage generating circuit 02 to turn on or off, with better control flexibility and richer control objects.

[0115] Optionally, the switch control circuit 04 may be configured to: receive an enable signal EN, and generate a first control signal VC and a second control signal VG based on the enable signal EN.

[0116] Optionally, in the same period, the potential of the second control signal VG may be opposite to the potential of the first control signal VC. That is, when the potential of the first control signal VC is high, the potential of the second control signal VG may be low; and when the potential of the first control signal VC is low, the potential of the second control signal VG may be high.

[0117] Accordingly, Fig.10 FIG. 4 is a schematic diagram showing a circuit structure of a switch control circuit 04. Fig.10 As shown, the switch control circuit 04 may include: a first inverter F1 and a second inverter F2.

[0118] The input end of the first inverter F1 can be used to receive the enable signal EN, the output end of the first inverter F1 can be connected to the self-starting circuit 03 and the input end of the second inverter F2 respectively, and the output end of the second inverter F2 can be connected to the current generating circuit 01. Fig.10 The self-starting circuit 03 and the current generating circuit 01 are not shown.

[0119] And combined with Fig.10It can be seen that in the embodiment of the present application, the switch control circuit 04 can generate the control signal (also called the switch control signal) required by each circuit in the bandgap reference circuit according to the enable signal EN (also called the input control signal), thereby controlling the opening and closing of each circuit. In addition, the switch control circuit 04 may include a two-stage inverter (i.e., a first inverter F1 and a second inverter F2), thereby generating two control signals with opposite phases. First, the switch control circuit 04 may perform a first inversion process on the potential of the enable signal EN through the first inverter F1 to obtain a signal EN1, and output it to the self-starting circuit 03. Correspondingly, it can be seen that the first control signal VC output to the self-starting circuit 03 is the signal EN1. Then, the switch control circuit 04 may perform a second inversion process on the signal EN1 through the second inverter F2 to obtain a signal EN2, and output it to the current generating circuit 01. Correspondingly, it can be seen that the second control signal VG output to the current generating circuit 01 is the signal EN2. In the same period, the potential of the signal EN1 is exactly opposite to the potential of the signal EN2.

[0120] Optionally, continue to refer to Fig.10 It can be seen that the first inverter F1 and the second inverter F2 may both include complementary metal-oxide-semiconductor field-effect transistors (CMOS transistors for short) connected between the power supply terminal VDD and the ground terminal GND.

[0121] It can be understood that CMOS transistors refer to transistors including P-type transistors and N-type transistors. Fig.10 In the figure, the P-type transistor and the N-type transistor in the CMOS tube included in the first inverter F1 are marked as M8 and M9 respectively; the P-type transistor and the N-type transistor in the CMOS tube included in the second inverter F2 are marked as M10 and M11 respectively.

[0122] Among them, the gate of the P-type transistor M8 and the gate of the N-type transistor M9 can both be used to receive the enable signal EN. For example, they can be connected to a separate enable terminal to receive the enable signal provided by the enable terminal. The source of the P-type transistor M8 can be connected to the power supply terminal VDD, the source of the N-type transistor M9 can be connected to the ground terminal GND, the drain of the P-type transistor M8 can be connected to the drain of the N-type transistor M9 and can output the signal EN1. The gate of the P-type transistor M10 and the gate of the N-type transistor M11 can both be used to receive the enable signal EN1, that is, they can be connected to the drain of the P-type transistor M8 and the drain of the N-type transistor M9. The source of the P-type transistor M10 can be connected to the power supply terminal VDD, the source of the N-type transistor M11 can be connected to the ground terminal GND, the drain of the P-type transistor M10 can be connected to the drain of the N-type transistor M11 and can output the signal EN2.

[0123] Optionally, Fig.11 FIG. 1 is a schematic diagram showing a circuit structure of a current generating circuit 01. Fig.11 As shown, the current generating circuit 01 may be a current generating circuit 01 with a self-biasing structure.

[0124] refer to Fig.11 It can be seen that the current generating circuit 01 may include: eight transistors, namely, the twelfth transistor M12 to the nineteenth transistor M19, two transistors, namely, the transistors T2 and T3, and six resistors, namely, the fourth resistor R4, the fifth resistor R5 and the sixth resistor R6. Fig.11 , no more details. And, combined with Fig.11 As can be seen from the structure shown, the current generating circuit 01 can generate PTAT current by using the voltage difference between the base and emitter of the two transistors T2 and T3. The width-to-length ratio of the two transistors T2 and T3 can be 1:N, where N can be any positive integer.

[0125] Optionally, combined Figure 4 , Figure 8 , Fig.10 and Fig.11 , Fig.12The overall circuit structure diagram of a bandgap reference circuit is schematically shown. In combination with the above-mentioned figures, it can be seen that the gate of the first transistor M1 in the voltage generating circuit 02 can be connected to the gate of the thirteenth transistor M13 in the current generating circuit 01, and the gate of the second transistor M2 in the voltage generating circuit 02 can be connected to the gate of the fifteenth transistor M15 in the current generating circuit 01, thereby establishing a connection between the current generating circuit 01 and the voltage generating circuit 02. The drain of the sixth transistor M6 in the self-starting circuit 03 can be connected to the connection point between the fourth resistor R4 and the sixteenth transistor M16 in the current generating circuit 01, thereby establishing a connection between the self-starting circuit 03 and the current generating circuit 01. The drain of the eighth transistor M8 and the drain of the ninth transistor M9 in the switch control circuit 04 can be connected to the gate of the third transistor M3, the gate of the fourth transistor M4 and the gate of the fifth transistor M5 in the self-starting circuit 03, thereby establishing a connection between the switch control circuit 04 and the self-starting circuit 03. Furthermore, the drain of the tenth transistor M10 and the drain of the eleventh transistor M11 in the switch control circuit 04 are connected to the gate of the twentieth transistor M20 in the current generating circuit 01, thereby establishing a connection between the switch control circuit 04 and the current generating circuit 01. Accordingly, the gate control signal of the twentieth transistor M20 in the current generating circuit 01 and the gate control signals of the third transistor M3 to the fifth transistor M5 in the self-starting circuit 03 can all come from the switch control circuit 04.

[0126] On this basis, the switch control circuit 04 can output two signals EN1 and EN2 with opposite potentials based on the received enable signal EN. Among them, EN1 can be transmitted to the self-starting circuit 03 as the first control signal VC to drive the self-starting circuit 03 to output the start control signal VO to the current generating circuit 01 in response to the first control signal VC. EN2 can be transmitted to the current generating circuit 01 as the second control signal VG to drive the current generating circuit 01 to control the on and off of the power supply terminal VDD and itself in response to the second control signal VG. The current generating circuit 01 can finally start and work in response to the start control signal VO and the second control signal VG to generate a PTAT current that varies with temperature. The voltage generating circuit 02 can first mirror the PTAT current, and then generate a first bandgap reference voltage that is basically invariant to temperature based on the mirrored PTAT current, and finally divide the first bandgap reference voltage to generate a second bandgap reference voltage that is basically invariant to temperature and is smaller than or even lower than 1V relative to the first bandgap reference voltage.

[0127] It is understandable that the various circuit structures described in the above embodiments are schematic illustrations, and any other alternative circuit structures can be applied to the embodiments of the present application. For example, a voltage regulator can be used instead of a voltage divider resistor (i.e., at least two first resistors R1) to achieve the same voltage reduction purpose. For another example, the voltage generating circuit 02 can also include the twentieth transistor M20 in the current generating circuit 01 to receive a control signal provided by the switch control circuit 04, and start to enter the working state in response to the control signal.

[0128] In summary, an embodiment of the present application provides a bandgap reference circuit. The bandgap reference circuit includes a current generating circuit and a voltage generating circuit. Since the voltage generating circuit can first generate a first bandgap reference voltage based on the positive temperature coefficient current generated by the current generating circuit, and then perform a secondary voltage reduction process on the generated first bandgap reference voltage to generate a second bandgap reference voltage, it can be seen that the voltage reduction process can be flexibly set so that the voltage generating circuit can flexibly generate a desired smaller bandgap reference voltage that is basically not affected by temperature according to actual needs, thereby better meeting the needs of different circuits, and the working flexibility of the bandgap reference circuit is better.

[0129] The present application also provides an electronic device. Fig.13 As shown, the electronic device includes: a load 10, and a bandgap reference circuit 00 as described in the above embodiment.

[0130] The bandgap reference circuit 00 is connected to the load 10 and is used to output a bandgap reference voltage to the load 10 .

[0131] It can be understood that the bandgap reference circuit 00 provided in the embodiment of the present application can output a relatively low bandgap reference voltage lower than 1V to the load 10, which can meet the complex requirements of various circuits and has more application scenarios.

[0132] Optionally, the load 10 may be, for example, an operational amplifier, a linear voltage regulator, a reference current source, etc. The electronic device may be, for example, a processor, a memory, a communication radio frequency device, etc.

[0133] It can be understood that, since the electronic device has substantially the same technical effects as the aforementioned bandgap reference circuit, the technical effects of the electronic device will not be described repeatedly here for the purpose of brevity.

[0134] It should be noted that the terms used in the embodiments of the present application are used to explain the embodiments of the present application, and are not intended to limit the present application. Unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present application should be the common meanings understood by people with ordinary skills in the field to which the present application belongs.

[0135] For example, the words "first", "second" or "third" and similar words used in the patent application specification and claims of this application do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "one" or "an" do not indicate a quantitative limitation, but rather indicate the existence of at least one. Words such as "include" or "comprise" mean that the elements or objects appearing before "include" or "comprise" include the elements or objects listed after "include" or "comprise" and their equivalents, and do not exclude other elements or objects. "Up", "down", "left" or "right" etc. are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly. "Connected" or "coupled" refers to an electrical connection. The character " / " generally indicates that the objects associated before and after are in an "or" relationship.

[0136] The above description is only an exemplary embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the principles of the present application shall be included in the protection scope of the present application.

Claims

1. A bandgap reference circuit, characterized in that: The bandgap reference circuit comprises: a current generating circuit and a voltage generating circuit; the current generating circuit is connected to the voltage generating circuit; The current generating circuit is used to: generate a positive temperature coefficient current; The voltage generating circuit is used for generating a first bandgap reference voltage based on the positive temperature coefficient current, and performing a voltage reduction process on the first bandgap reference voltage to generate a second bandgap reference voltage.

2. The bandgap reference circuit according to claim 1, characterized in that: The voltage reduction process includes: voltage division process; the voltage generating circuit includes: a voltage generating subcircuit and a voltage dividing subcircuit; the voltage generating subcircuit is connected to the current generating circuit and the voltage dividing subcircuit respectively; The voltage generating subcircuit and the voltage dividing subcircuit are used to: generate the first bandgap reference voltage based on the positive temperature coefficient current; The voltage division subcircuit is further used for: performing voltage division processing on the first bandgap reference voltage to generate the second bandgap reference voltage.

3. The bandgap reference circuit according to claim 2, characterized in that: The voltage dividing subcircuit comprises: at least two first resistors; The at least two first resistors are sequentially connected in series, with one end of the series connection connected to the voltage generating subcircuit and the other end of the series connection being grounded, wherein at least one series node is used to output the second bandgap reference voltage.

4. The bandgap reference circuit according to claim 2, characterized in that: The voltage generating subcircuit comprises: a current mirror unit and a voltage generating unit; the current mirror unit is connected to the current generating circuit and the voltage generating unit respectively, and the voltage generating unit is also connected to the voltage dividing subcircuit; The current mirror unit is used to: output the positive temperature coefficient current mirror image to the voltage generating unit; The voltage generating unit and the voltage dividing sub-circuit are used to generate the first bandgap reference voltage based on the positive temperature coefficient current output by the current mirror unit.

5. The bandgap reference circuit according to claim 4, characterized in that: The current mirror unit includes: a first transistor and a second transistor; the voltage generating unit includes: a second resistor, a third resistor and a triode; The gate of the first transistor and the gate of the second transistor are both connected to the current generating circuit, the source of the first transistor is connected to the power supply terminal, the drain of the first transistor is connected to the source of the second transistor, the drain of the second transistor is connected to one end of the second resistor, the other end of the second resistor is connected to one end of the third resistor, the other end of the third resistor is connected to the emitter of the transistor, and the base and collector of the transistor are both grounded; and the voltage divider subcircuit is connected to the connection point of the second resistor and the third resistor.

6. The bandgap reference circuit according to any one of claims 1 to 5, characterized in that: The bandgap reference circuit further includes: a self-starting circuit; the self-starting circuit is connected to the current generating circuit; The self-starting circuit is used to: receive a first control signal, and output a start control signal to the current generating circuit based on the first control signal; The current generating circuit is used for generating the positive temperature coefficient current in response to the start control signal.

7. The bandgap reference circuit according to claim 6, characterized in that: The self-starting circuit comprises: a first control subcircuit, a second control subcircuit and a charge-discharge electronic circuit; the first control subcircuit is respectively connected to a power supply terminal, a ground terminal and a control node, the second control subcircuit is respectively connected to the control node, the power supply terminal and the current generating circuit, and the charge-discharge electronic circuit is connected between the control node and the ground terminal; The first control subcircuit is used to: receive the first control signal, and in response to the first control signal, control the connection and disconnection between the power supply terminal and the control node, control the connection and disconnection between the ground terminal and the control node, and adjust the potential of the control node by charging and discharging the charge-discharge electronic circuit; The second control subcircuit is used to receive the first control signal, and in response to the first control signal and the potential of the control node, control the connection and disconnection between the power supply terminal and the current generating circuit to output the start control signal to the current generating circuit.

8. The bandgap reference circuit according to claim 7, characterized in that: The first control subcircuit includes: a third transistor and a fourth transistor; The gate of the third transistor is used to receive the first control signal, the source of the third transistor is connected to the power supply terminal, and the drain of the third transistor is connected to the control node; The gate of the fourth transistor is used to receive the first control signal, the source of the fourth transistor is connected to the ground terminal, and the drain of the fourth transistor is connected to the control node.

9. The bandgap reference circuit according to claim 7, characterized in that: The second control subcircuit includes: a fifth transistor and a sixth transistor; The gate of the fifth transistor is used to receive the first control signal, the source of the fifth transistor is connected to the power supply terminal, the drain of the fifth transistor is connected to the source of the sixth transistor, the gate of the sixth transistor is connected to the control node, and the drain of the sixth transistor is connected to the current generating circuit.

10. The bandgap reference circuit according to claim 7, characterized in that: The charging and discharging electronic circuit comprises: a seventh transistor; A gate of the seventh transistor is connected to the control node, and a source and a drain of the seventh transistor are connected to the ground terminal.

11. The bandgap reference circuit according to claim 6, characterized in that: The bandgap reference circuit further includes: a switch control circuit; the switch control circuit is connected to the self-starting circuit; The switch control circuit is used to output the first control signal to the self-starting circuit.

12. The bandgap reference circuit according to claim 11, characterized in that: The switch control circuit is also connected to the current generating circuit; The switch control circuit is further used to: output a second control signal to the current generating circuit; The current generating circuit is used for generating the positive temperature coefficient current in response to the start control signal and the second control signal.

13. The bandgap reference circuit according to claim 12, characterized in that: The switch control circuit is used to receive an enable signal and generate the first control signal and the second control signal based on the enable signal.

14. The bandgap reference circuit according to claim 13, characterized in that: In the same period, the potential of the second control signal is opposite to the potential of the first control signal; the switch control circuit comprises: a first inverter and a second inverter; The input end of the first inverter is used to receive the enable signal, the output end of the first inverter is connected to the input end of the self-starting circuit and the second inverter respectively, and the output end of the second inverter is connected to the current generating circuit.

15. The bandgap reference circuit according to claim 14, characterized in that: The first inverter and the second inverter each include a complementary metal oxide semiconductor field effect transistor connected between a power supply terminal and a ground terminal.

16. The bandgap reference circuit according to any one of claims 1 to 5, characterized in that: The current generating circuit is a current generating circuit with a self-bias structure.

17. An electronic device, characterized in that: The electronic device comprises: a load, and a bandgap reference circuit as claimed in any one of claims 1 to 16; The bandgap reference circuit is connected to the load and is used to output a bandgap reference voltage to the load.

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