Band gap comparator, power management system, chip and electronic equipment

Abstract

The invention provides a band gap comparator, a power management system, a chip and electronic equipment. Under the action of the enable signal, the low-voltage protection circuit can work. Therefore, when the low-voltage protection circuit monitors that the current of the comparison circuit is greater than the preset current, the first signal is transmitted to the comparison circuit, so that the comparison circuit can obtain the first signal. Therefore, the comparison circuit can compare the power supply voltage with the reference voltage according to the first signal to obtain the comparison signal, so that the comparison circuit can monitor the power supply voltage. The low-voltage protection circuit judges whether the comparison circuit has a certain current capability or not by monitoring the magnitude relationship between the current of the comparison circuit and the preset current, so that the low-voltage protection circuit can monitor whether the power supply voltage is within the preset voltage range or not without setting a resistor with a very large resistance value. Therefore, the area cost of the low-voltage protection circuit is reduced, and the area cost of the band gap comparator is lower. Meanwhile, the low-voltage protection circuit can realize lower power consumption.

Description

Technical Field

[0001] The present application relates to the technical field of power management chips, and in particular to a bandgap comparator, a power management system, a chip and an electronic device. Background Art

[0002] The safety of the power management system is of vital importance. In order to ensure the safety of the power management system, a bandgap comparator circuit is usually used to monitor the power supply voltage in the power management system to monitor and protect the power supply voltage from overvoltage and undervoltage. The bandgap comparator circuit generally includes a low-voltage protection circuit. When the low-voltage protection circuit detects that the power supply voltage meets the preset voltage value, the bandgap comparator circuit is turned on to enable the bandgap comparator circuit to work.

[0003] However, if the power consumption of the low voltage protection circuit is reduced to nA level, a resistor with a large resistance value needs to be set in the low voltage protection circuit, resulting in a large area cost of the low voltage protection circuit and a large area cost of the bandgap comparator. Summary of the invention

[0004] The present application provides a bandgap comparator, a power management system, a chip and an electronic device, which can reduce the area cost of a low-voltage protection circuit, reduce the area cost of the bandgap comparator, and have low power consumption.

[0005] In a first aspect, the present application provides a bandgap comparator, which includes: a comparison circuit and a low-voltage protection circuit.

[0006] The input end of the low-voltage protection circuit is used to access an enable signal, and the enable signal is used to enable the low-voltage protection circuit. The first end of the low-voltage protection circuit is electrically connected to the first end of the comparison circuit, and the second end of the low-voltage protection circuit is electrically connected to the second end of the comparison circuit. The output end of the low-voltage protection circuit is electrically connected to the third end and the fourth end of the comparison circuit respectively. The input end of the comparison circuit is used to access an input voltage, and the input voltage is related to the power supply voltage. The output end of the comparison circuit is used to output a comparison signal, and the comparison signal is used to characterize whether the power supply voltage is within a preset voltage range.

[0007] The low voltage protection circuit is used to transmit a first signal to the comparison circuit when it is detected that the current of the comparison circuit is greater than a preset current under the action of an enable signal, and the first signal is used to enable the comparison circuit.

[0008] The comparison circuit is used to compare the input voltage and the reference voltage according to the first signal to obtain a comparison signal.

[0009] Through the bandgap comparator provided by the first aspect, the low-voltage protection circuit can work under the action of the enable signal for enabling the low-voltage protection circuit. In this way, when the low-voltage protection circuit detects that the current of the comparison circuit is greater than the preset current, the first signal for enabling the comparison circuit is transmitted to the comparison circuit, so that the comparison circuit can obtain the first signal. In this way, the comparison circuit can compare the power supply voltage and the reference voltage according to the first signal for enabling the comparison circuit, and obtain a comparison signal, so that the comparison circuit can monitor the power supply voltage. Since the low-voltage protection circuit determines whether the comparison circuit has a certain current capacity by monitoring the magnitude relationship between the current of the comparison circuit and the preset current, the low-voltage protection circuit can monitor whether the power supply voltage is within the preset voltage range without setting a resistor with a very large resistance value. Thereby, the area cost of the low-voltage protection circuit can be reduced, and the area cost of the bandgap comparator is low. At the same time, the low-voltage protection circuit can achieve lower power consumption.

[0010] In one possible design, the low voltage protection circuit includes: a first pull-up circuit, a first pull-down circuit and a first signal output circuit.

[0011] The first end of the first pull-up circuit is electrically connected to the first end of the first signal output circuit, the control end of the first pull-up circuit and the control end of the first pull-down circuit are both used to access the enable signal, the second end of the first pull-up circuit and the second end of the first signal output circuit are both electrically connected to the first end of the comparison circuit, the third end of the first signal output circuit is electrically connected to the first end of the first pull-down circuit, the fourth end of the first signal output circuit is electrically connected to the second end of the comparison circuit, the fifth end of the first signal output circuit is electrically connected to the third end of the comparison circuit, and the sixth end of the first signal output circuit and the second end of the first pull-down circuit are both grounded.

[0012] The first pull-up circuit is used to disconnect the pull-up of the first signal output circuit when the enable signal is at a high level.

[0013] The first pull-down circuit is used to disconnect the pull-down of the first signal output circuit when the enable signal is at a high level.

[0014] The first signal output circuit is used to output a first signal when the current of the comparison circuit is greater than a preset current after the pull-up of the first pull-up circuit and the pull-down of the first pull-down circuit are both disconnected.

[0015] In one possible design, the first signal output circuit includes: a first signal amplifying component, a current monitoring component, a first mirror component, a second mirror component and a current output component.

[0016] The first end of the current monitoring component is electrically connected to the first end of the first pull-up circuit, the second end of the current monitoring component is electrically connected to the first end of the comparison circuit, the third end of the current monitoring component is electrically connected to the first end of the first mirror component, the first end of the first pull-down circuit and the input end of the first signal amplification component are both electrically connected between the third end of the current monitoring component and the first end of the first mirror component, the second end of the first mirror component is respectively electrically connected to the first end of the current output component and the second end of the second mirror component, the first end of the second mirror component is electrically connected to the second end of the comparison circuit, the output end of the first signal amplification component is electrically connected to the third end of the comparison circuit, and the third end of the first mirror component, the second end of the current output component, and the third end of the second mirror component are all grounded.

[0017] The current output component is used to output a first current, and the first current is used as a pull-down current.

[0018] The first mirror component is used to mirror the first current to obtain a second current, and transmit the second current to the first signal amplifying component, and the second current is used to pull down the potential of the input terminal of the first signal amplifying component.

[0019] The second mirror component is used for mirroring the first current to obtain a third current, and transmit the third current to the comparison circuit, and the third current is used for pulling down the potential of the second end of the comparison circuit.

[0020] The current monitoring component is used to monitor the current of the comparison circuit, obtain a fourth current, and transmit the fourth current to the first signal amplifying component, and the fourth current is used to pull up the potential of the input terminal of the first signal amplifying component.

[0021] The first signal amplifying component is used to obtain a first signal when the fourth current is greater than the second current.

[0022] In a possible design, the first signal amplifying component includes: a first Schmitt trigger, a first inverter, and a second inverter.

[0023] The input end of the first Schmitt trigger is electrically connected between the third end of the current monitoring component and the first end of the first mirror component, the output end of the first Schmitt trigger is electrically connected to the input end of the first inverter, the output end of the first inverter is electrically connected to the input end of the second inverter, and the output end of the second inverter is electrically connected to the third end of the comparison circuit.

[0024] In a possible design, the current output component includes: a current source and a first transistor.

[0025] The output end of the current source is electrically connected to the first end of the first transistor, the control end of the first transistor and the second end of the first mirror component respectively, and the second end of the first transistor is grounded.

[0026] In one possible design, the comparison circuit includes: a first resistor, a second resistor, a third resistor, a current mirror, a first transistor, a second transistor, a second pull-up circuit, a second pull-down circuit, and a second transistor.

[0027] The first end of the first transistor is electrically connected to the first end of the current mirror, the first end of the low voltage protection circuit is electrically connected between the first end of the first transistor and the first end of the current mirror, the second end of the current mirror is electrically connected to the first end of the second transistor, the third end of the current mirror and the first end of the second pull-up circuit are both electrically connected to the second end of the second transistor, the second end of the second pull-up circuit and the control end of the second transistor are both electrically connected between the second end of the current mirror and the first end of the second transistor, the first end of the second transistor is electrically connected to the first end of the second pull-down circuit, the control end of the second pull-up circuit and the control end of the second pull-down circuit are both connected to the low voltage protection circuit. The output end of the low voltage protection circuit is electrically connected, the second end of the low voltage protection circuit is electrically connected between the first end of the second transistor and the first end of the second pull-down circuit, the second end of the first triode and the second end of the second triode are both used to access the power supply voltage, the third end of the first triode is electrically connected to the first end of the first resistor, the second end of the first resistor is electrically connected to the third end of the second triode, the first end of the second resistor is electrically connected between the second end of the first resistor and the third end of the second triode, the second end of the second resistor is electrically connected to the first end of the third resistor, and the second end of the third resistor and the second end of the second pull-down circuit are grounded.

[0028] The second pull-up circuit is used to disconnect the pull-up of the second end of the current mirror according to the first signal, so that the comparison circuit obtains a comparison signal.

[0029] The second pull-down circuit is used to disconnect the pull-down of the first end of the second transistor according to the first signal, so that the comparison circuit obtains a comparison signal.

[0030] In one possible design, the first pull-down circuit or the second pull-down circuit includes: a third inverter and a third transistor.

[0031] The input end of the third inverter is used to access the enable signal, or is electrically connected to the output end of the low-voltage protection circuit, the output end of the third inverter is electrically connected to the control end of the third transistor, the first end of the third transistor is electrically connected to the third end of the first signal output circuit, or the first end of the second transistor, and the second end of the third transistor is grounded.

[0032] In one possible design, the bandgap comparator further includes: a signal output circuit.

[0033] The first input end of the signal output circuit is electrically connected to the output end of the comparison circuit, the second input end of the signal output circuit is electrically connected to the output end of the low-voltage protection circuit, and the output end of the signal output circuit is used to output a protection signal, which is used to indicate whether the power supply voltage is undervoltage or overvoltage.

[0034] The signal output circuit is used to output a protection signal according to the comparison signal.

[0035] In one possible design, the signal output circuit includes: a second signal amplification component and a logic processing component.

[0036] The input end of the second signal amplifying component is electrically connected to the output end of the comparison circuit, the output end of the second signal amplifying component is electrically connected to the first input end of the logic processing component, the second input end of the logic processing component is electrically connected to the output end of the low-voltage protection circuit, and the output end of the logic processing component is used to output a protection signal.

[0037] The second signal amplifying component is used to amplify the comparison signal to obtain an amplified comparison signal, and transmit the amplified comparison signal to the logic processing component.

[0038] The logic processing component is used to perform a logic operation on the amplified comparison signal and the first signal to obtain a protection signal.

[0039] In a possible design, the second signal amplifying component includes: a second Schmitt trigger, a fourth inverter, and a fifth inverter.

[0040] The input end of the second Schmitt trigger is electrically connected to the output end of the comparison circuit, the output end of the second Schmitt trigger is electrically connected to the input end of the fourth inverter, the output end of the fourth inverter is electrically connected to the input end of the fifth inverter, and the output end of the fifth inverter is used to output a protection signal.

[0041] In one possible design, the comparison circuit also includes: a fourth transistor.

[0042] The control end of the fourth transistor is electrically connected to the output end of the second signal amplifying component, the first end of the fourth transistor is electrically connected between the second end of the second resistor and the first end of the third resistor, and the second end of the fourth transistor is grounded.

[0043] In one possible design, the low-voltage protection circuit is also used to transmit a second signal to the comparison circuit when the enable signal is at a high level and it is monitored that the current of the comparison circuit is less than or equal to a preset current, or when the enable signal is at a low level, and the second signal is used to indicate that the comparison circuit is not working.

[0044] The comparison circuit is also used to stop monitoring the power supply voltage under the action of the second signal, obtain a third signal, and transmit the third signal to the signal output circuit.

[0045] The signal output circuit is further used to obtain an error signal according to the third signal, and the error signal is used to indicate that the power supply voltage is lower than a preset voltage.

[0046] In a second aspect, the present application provides a power management system, comprising: the bandgap comparator in the above-mentioned first aspect and each possible design of the above-mentioned first aspect.

[0047] The beneficial effects of the power management system provided in the above-mentioned second aspect and each possible design of the above-mentioned second aspect can be referred to the beneficial effects brought about by the above-mentioned first aspect and each possible implementation method of the first aspect, and will not be repeated here.

[0048] In a third aspect, the present application provides a chip, comprising: the power management system in the above-mentioned second aspect.

[0049] In a fourth aspect, the present application provides an electronic device, which includes the chip in the third aspect above. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 A schematic diagram of the structure of a bandgap comparator provided in an embodiment of the present application;

[0051] Figure 2 A schematic diagram of the structure of another bandgap comparator provided in an embodiment of the present application. DETAILED DESCRIPTION

[0052] In this application, "at least one" means one or more, and "plurality" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. The character " / " generally indicates that the associated objects before and after are in an "or" relationship. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, at least one of a, b, or c alone can represent: a, b, c, a and b, a and c, or a, b, and c, where a, b, and c can be single or multiple. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0053] The directions or positional relationships indicated by terms such as "center", "longitudinal", "lateral", "up", "down", "left", "right", "front", and "back" are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present application and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present application.

[0054] The terms "connected" and "connected" should be understood in a broad sense. For example, the "connected" or "connected" of a circuit structure can refer to not only physical connection, but also electrical connection or signal connection. For example, it can be directly connected, that is, physically connected, or indirectly connected through at least one intermediate element, as long as the circuit is connected, or it can be the internal connection of two elements; signal connection can refer to signal connection through a circuit or through a media medium, such as radio waves. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0055] The power management system generally includes: comparators, logic circuits and internal devices. When the power supply voltage is lower than the normal working range, it will cause logic circuit errors, making some circuits in the power management system work abnormally. When the power supply voltage is higher than the normal working range, it will cause internal devices to be damaged, causing the chip where the power management system is located to burn out and other serious consequences.

[0056] For the corresponding monitoring and protection of the power supply voltage overvoltage and the power supply voltage undervoltage, the power supply voltage and the reference voltage are compared by a comparator. Since the reference voltage is generated by a bandgap reference circuit, the comparator requires a comparator circuit and a bandgap reference circuit, which makes the power consumption of the comparator larger. In addition, before the bandgap reference circuit is established, the comparator cannot monitor the power supply voltage.

[0057] The bandgap reference circuit can be replaced by a MOS tube. In this way, the threshold voltage of the MOS tube is used as a reference voltage to compare with the power supply voltage. However, since the threshold voltage of the MOS tube is unstable and has a large temperature drift, the accuracy of the comparator in monitoring the power supply voltage cannot be guaranteed.

[0058] Therefore, the power supply voltage is monitored by combining a comparator circuit with a bandgap reference circuit, that is, a bandgap comparator circuit. In this way, the problem of needing a bandgap reference circuit to monitor the power supply voltage can be solved, and the stability of the reference voltage and small temperature drift can be ensured.

[0059] The bandgap comparator circuit in the related art can monitor the power supply voltage while ensuring high integration, so as to ensure that the bandgap comparator circuit has an output result with a certain accuracy. However, the bandgap comparator circuit requires a certain power supply voltage to have load capacity. When the power supply voltage is low, the output state of the bandgap comparator circuit is uncertain, causing the output result of the bandgap comparator circuit to be erroneously flipped.

[0060] Therefore, the power supply voltage is monitored by a low-voltage protection circuit with a function of preventing false flipping. When the low-voltage protection circuit detects that the power supply voltage meets the preset voltage value, the bandgap comparator circuit is turned on to enable the bandgap comparator circuit to work. The low-voltage protection circuit is implemented by a simple power supply voltage comparison circuit.

[0061] Although the power consumption of the low-voltage protection circuit in the related technology has been reduced to a few uA level, for the lower nA level power consumption, a resistor with a large resistance value needs to be set in the low-voltage protection circuit, resulting in a large area cost of the low-voltage protection circuit and a large area cost of the bandgap comparator.

[0062] The essence of the low voltage protection circuit is that the bandgap comparator circuit outputs the result only after the bandgap comparator circuit has a certain current capability, and the core components in the bandgap comparator circuit only require a current of several hundred nA to work normally.

[0063] Therefore, the present application monitors the current of the core components in the bandgap comparator circuit through the low voltage protection circuit to determine whether the bandgap comparator has a certain current capability, that is, after the low voltage protection circuit monitors that the bandgap comparator has a certain current capability, the bandgap comparator is enabled. Thus, the bandgap comparator will correctly monitor the power supply voltage.

[0064] The present application provides a bandgap comparator, a power management system, a chip and an electronic device.

[0065] The power management system may be a chip or a circuit module.

[0066] In this application, electronic devices may include but are not limited to: mobile phones, wireless communication devices, smart home devices, and tablet computers.

[0067] Reference Figure 1 , Figure 1 A schematic diagram of the structure of a bandgap comparator provided in an embodiment of the present application. Figure 1 As shown, the bandgap comparator 1000 may include: a comparison circuit 200 and a low voltage protection circuit 100 .

[0068] The input end of the low voltage protection circuit 100 is used to access the enable signal ENB1_CMP, and the enable signal ENB1_CMP is used to enable the low voltage protection circuit 100. The first end of the low voltage protection circuit 100 is electrically connected to the first end of the comparison circuit 200, and the second end of the low voltage protection circuit 100 is electrically connected to the second end of the comparison circuit 200. The output end of the low voltage protection circuit 100 is electrically connected to the third end and the fourth end of the comparison circuit 200 respectively. The input end of the comparison circuit 200 is used to access the input voltage VIN, and the input voltage VIN is related to the power supply voltage VDD. The output end of the comparison circuit 200 is used to output a comparison signal.

[0069] The comparison signal is used to indicate whether the power supply voltage VDD is within a preset voltage range.

[0070] The comparison circuit 200 and the low voltage protection circuit 100 may be arranged separately or integratedly.

[0071] Figure 1 In the figure, the first end of the low voltage protection circuit 100 is recorded as 1, the second end of the low voltage protection circuit 100 is recorded as 2, the input end of the low voltage protection circuit 100 is recorded as 3, the output end of the low voltage protection circuit 100 is recorded as 4, the first end of the comparison circuit 200 is recorded as 1, the second end of the comparison circuit 200 is recorded as 2, the third end of the comparison circuit 200 is recorded as 3, the fourth end of the comparison circuit 200 is recorded as 4, the input end of the comparison circuit 200 is recorded as 5, and the output end of the comparison circuit 200 is recorded as 6.

[0072] In some examples, the power supply voltage VDD is converted into the input voltage VIN by a voltage divider circuit formed by resistors R4 and R5. In this way, the input voltage VIN can be input to the comparison circuit 200. Thus, the comparison circuit 200 can monitor the power supply voltage VDD.

[0073] The input voltage VIN can be calculated according to formula (1):

[0074] VIN=VDD*r5 / (r4+r5) (1)

[0075] Wherein, VIN is the input voltage, VDD is the power supply voltage, r4 is the resistance value of the resistor R4, and r5 is the resistance value of the resistor R5.

[0076] For example, when the enable signal ENB1_CMP is at a high level, the low voltage protection circuit 100 can work under the action of the enable signal ENB1_CMP. In this way, when the low voltage protection circuit 100 detects that the current of the comparison circuit 200 is greater than the preset current, it means that when the low voltage protection circuit 100 detects that the comparison circuit 200 has a certain current capability, the low voltage protection circuit 100 can obtain the first signal ENB2_CMP1. In addition, the low voltage protection circuit 100 can transmit the first signal ENB2_CMP1 to the comparison circuit 200, so that the comparison circuit 200 can obtain the first signal ENB2_CMP1.

[0077] The first signal ENB2_CMP1 is used to enable the comparison circuit 200 .

[0078] In this way, after the first signal ENB2_CMP1 enables the comparison circuit 200, the comparison circuit 200 can work, and the comparison circuit 200 can be prevented from erroneously flipping, thereby ensuring that the bandgap comparator 1000 will not erroneously flip. In this way, after the comparison circuit 200 can work, the comparison circuit 200 can compare the power supply voltage VDD with the reference voltage to obtain a comparison signal, so that the comparison circuit can monitor the power supply voltage VDD.

[0079] Among them, since the low voltage protection circuit 100 determines whether the comparison circuit 200 has a certain current capacity by monitoring the magnitude relationship between the current of the comparison circuit 200 and the preset current, the low voltage protection circuit 100 can monitor whether the power supply voltage VDD is within the preset voltage range without setting a resistor with a very large resistance value, that is, whether the power supply voltage VDD is within the normal operating voltage range. Therefore, the area cost of the low voltage protection circuit 100 can be reduced, and the area cost of the bandgap comparator 1000 is relatively low.

[0080] At the same time, compared with the low voltage protection circuit that monitors the power supply voltage, the low voltage protection circuit 100 can achieve lower power consumption.

[0081] The bandgap comparator, power management system, chip and electronic device provided by the present application can work under the action of the enable signal for enabling the low-voltage protection circuit. In this way, when the low-voltage protection circuit detects that the current of the comparison circuit is greater than the preset current, the first signal for enabling the comparison circuit is transmitted to the comparison circuit, so that the comparison circuit can obtain the first signal. In this way, the comparison circuit can compare the power supply voltage and the reference voltage according to the first signal for enabling the comparison circuit, and obtain the comparison signal, so that the comparison circuit can monitor the power supply voltage. Since the low-voltage protection circuit determines whether the comparison circuit has a certain current capacity by monitoring the magnitude relationship between the current of the comparison circuit and the preset current, the low-voltage protection circuit can monitor whether the power supply voltage is within the preset voltage range without setting a resistor with a very large resistance value. Thereby, the area cost of the low-voltage protection circuit can be reduced, and the area cost of the bandgap comparator is low. At the same time, the low-voltage protection circuit can achieve lower power consumption.

[0082] Based on the description of the above embodiment, a possible implementation of the low voltage protection circuit 100 is exemplified. Figure 2 , Figure 2 Shows Figure 1 Schematic diagram of the structure of the medium bandgap comparator. Figure 2 As shown, the low voltage protection circuit 100 may include: a first pull-up circuit 110 , a first pull-down circuit 120 and a first signal output circuit 130 .

[0083] The first end of the first pull-up circuit 110 is electrically connected to the first end of the first signal output circuit 130, the control end of the first pull-up circuit 110 and the control end of the first pull-down circuit 120 are both used to access the enable signal ENB1_CMP, the second end of the first pull-up circuit 110 and the second end of the first signal output circuit 130 are both electrically connected to the first end of the comparison circuit 200, the third end of the first signal output circuit 130 is electrically connected to the first end of the first pull-down circuit 120, the fourth end of the first signal output circuit 130 is electrically connected to the second end of the comparison circuit 200, the fifth end of the first signal output circuit 130 is electrically connected to the third end of the comparison circuit 200, and the sixth end of the first signal output circuit 130 and the second end of the first pull-down circuit 120 are both grounded.

[0084] In some examples, the first pull-up circuit 110 may include: a fifth P-type transistor MP5 .

[0085] When the enable signal ENB1_CMP is at a high level, the first pull-up circuit 110 is turned off, so that the first pull-up circuit 110 can stop pulling up the first signal output circuit 130 .

[0086] When the enable signal ENB1_CMP is at a high level, the first pull-down circuit 120 is turned off, so that the first pull-down circuit 120 can stop pulling down the first signal output circuit 130 .

[0087] Thus, after the pull-up of the first pull-up circuit 110 and the pull-down of the first pull-down circuit 120 are both disconnected, when the current of the comparison circuit 200 is greater than the preset current, the first signal output circuit 130 can output the first signal ENB2_CMP1, so that the first signal output circuit 130 can transmit the first signal ENB2_CMP1 to the comparison circuit 120.

[0088] Among them, after the first pull-up circuit 110 and the first pull-down circuit 120 are turned off, when the current of the comparison circuit 200 is greater than the preset current, it means that the current of the comparison circuit 120 is large, that is, the current capacity of the comparison circuit 120 is sufficient, so that the comparison circuit 120 can output a comparison signal.

[0089] In summary, when the enable signal is at a high level, the first pull-up circuit can disconnect the pull-up of the first signal output circuit, and the first pull-down circuit can disconnect the pull-down of the first signal output circuit. In this way, after the pull-up of the first pull-up circuit and the pull-down of the first pull-down circuit are disconnected, when the current of the comparison circuit is greater than the preset current, the first signal output circuit can output the first signal, so that the comparison circuit can output the comparison signal.

[0090] Based on the description of the above embodiment, a possible implementation of the first signal output circuit 130 is exemplified. Figure 2 As shown, the first signal output circuit 130 may include: a first signal amplifying component 131 , a current monitoring component 132 , a first mirror component 133 , a second mirror component 134 and a current output component 135 .

[0091] The first end of the current monitoring component 132 is electrically connected to the first end of the first pull-up circuit 110, the second end of the current monitoring component 132 is electrically connected to the first end of the comparison circuit 200, the third end of the current monitoring component 132 is electrically connected to the first end of the first mirror component 133, the first end of the first pull-down circuit 120 and the input end of the first signal amplification component 131 are both electrically connected between the third end of the current monitoring component 132 and the first end of the first mirror component 133, the second end of the first mirror component 133 is electrically connected to the first end of the current output component 135 and the second end of the second mirror component 134 respectively, the first end of the second mirror component 134 is electrically connected to the second end of the comparison circuit 200, the output end of the first signal amplification component 131 is electrically connected to the third end of the comparison circuit 200, and the third end of the first mirror component 133, the second end of the current output component 135 and the third end of the second mirror component 134 are all grounded.

[0092] The node B is located between the second terminal of the current monitoring component 132 and the first terminal of the comparison circuit 200 .

[0093] In some examples, the current output component 135 can include: a current source and a first transistor M1 .

[0094] The output end of the current source is electrically connected to the first end of the first transistor M1 , the control end of the first transistor M1 and the second end of the first mirror component 133 , respectively. The second end of the first transistor M1 is grounded.

[0095] The current source outputs the first current Ib, so that the current output component 135 can output the first current Ib.

[0096] The first current Ib is used as a pull-down current. For example, the first current Ib is a pull-down current of 200 nA.

[0097] In some examples, the first mirror component 133 and the second mirror component 134 may include an N-type transistor MN.

[0098] The first mirror component 133 and the first transistor M1 form a current mirror, so that the first mirror component 133 can mirror the first current Ib. In this way, the first mirror component 133 can obtain the second current. In addition, the first mirror component 133 can transmit the second current to the first signal amplifying component 131, so that the first signal amplifying component 131 can obtain the second current.

[0099] The second current is used to pull down the potential of the input terminal of the first signal amplifying component 131 , that is, the potential of the node A.

[0100] The second mirror component 134 and the first transistor M1 form a current mirror, so that the second mirror component 134 can mirror the first current Ib. In this way, the second mirror component 134 can obtain the third current. In addition, the second mirror component 134 can transmit the third current to the comparison circuit 120.

[0101] The third current is used to pull down the potential of the second terminal of the comparison circuit 200 .

[0102] In some examples, the current monitoring component 132 can include: a fourth P-type transistor.

[0103] Since the fourth P-type transistor can mirror the current of the first terminal of the comparison circuit 120, the current monitoring component 132 can monitor the current of the comparison circuit 200. In this way, the current monitoring component 132 can obtain the fourth current. In addition, the current monitoring component 132 can transmit the fourth current to the first signal amplification component 131.

[0104] The fourth current is used to pull up the potential of the input terminal of the first signal amplifying component 131 , that is, the potential of the node A.

[0105] In some examples, the first signal amplifying component 131 may include a first Schmitt trigger SMT1 , a first inverter INV1 , and a second inverter INV2 .

[0106] The input end of the first Schmitt trigger SMT1 is electrically connected between the third end of the current monitoring component 132 and the first end of the first mirror component 133, the output end of the first Schmitt trigger SMT1 is electrically connected to the input end of the first inverter INV1, the output end of the first inverter INV1 is electrically connected to the input end of the second inverter INV2, and the output end of the second inverter INV2 is electrically connected to the third end of the comparison circuit 200.

[0107] Furthermore, when the fourth current is greater than the second current, the potential of the node A is at a high level, so that the input end of a Schmitt trigger SMT1 is at a high level. After passing through the first Schmitt trigger SMT1, the first inverter INV1 and the second inverter INV2, the output end of the second inverter INV2 is at a high level, so that the first signal amplifying component 131 can obtain the first signal ENB2_CMP1, and the first signal output circuit 130 can obtain the first signal ENB2_CMP1.

[0108] In summary, the current output component outputs a first current used as a pull-down current. The first current can be mirrored by the first mirror component, so that the first mirror component can obtain a second current. In addition, the first mirror component can transmit a second current for pulling down the potential of the input end of the first signal amplification component to the first signal amplification component, so that the first signal amplification component can obtain the second current. The second mirror component can mirror the first current, so that the second mirror component can obtain a third current. In addition, the second mirror component can transmit a third current for pulling down the potential of the second end of the comparison circuit to the comparison circuit, so that the comparison circuit can obtain the third current. The current monitoring component can monitor the current of the comparison circuit, so that the current monitoring component can obtain a fourth current, and transmit a fourth current for pulling up the potential of the input end of the first signal amplification component to the first signal amplification component. Furthermore, when the fourth current is greater than the second current, the first signal amplification component can obtain a first signal. Thus, the first signal output circuit can obtain a first signal.

[0109] Based on the description of the above embodiment, a possible implementation of the comparison circuit 200 is exemplified. Figure 2 As shown, the comparison circuit 200 may include: a first resistor R1, a second resistor R2, a third resistor R3, a current mirror 210, a first transistor Q1, a second transistor Q2, a second pull-up circuit 220, a second pull-down circuit 230 and a second transistor M2.

[0110] The first end of the first transistor Q1 is electrically connected to the first end of the current mirror 210, the first end of the low voltage protection circuit 100 is electrically connected between the first end of the first transistor Q1 and the first end of the current mirror 210, the second end of the current mirror 210 is electrically connected to the first end of the second transistor Q2, the third end of the current mirror 210 and the first end of the second pull-up circuit 220 are both electrically connected to the second end of the second transistor M2, the second end of the second pull-up circuit 220 and the control end of the second transistor M2 are both electrically connected between the second end of the current mirror 210 and the first end of the second transistor Q2, the first end of the second transistor M2 is electrically connected to the first end of the second pull-down circuit 230, the control end of the second pull-up circuit 220 and the control end of the second pull-down circuit 230 are both electrically connected to the The output end of the low voltage protection circuit 100 is electrically connected, the second end of the low voltage protection circuit 100 is electrically connected between the first end of the second transistor M2 and the first end of the second pull-down circuit 230, the second end of the first transistor Q1 and the second end of the second transistor Q2 are both used to access the input voltage VIN, the third end of the first transistor Q1 is electrically connected to the first end of the first resistor R1, the second end of the first resistor R1 is electrically connected to the third end of the second transistor Q2, the first end of the second resistor R2 is electrically connected between the second end of the first resistor R1 and the third end of the second transistor Q2, the second end of the second resistor R2 is electrically connected to the first end of the third resistor R3, and the second end of the third resistor R3 and the second end of the second pull-down circuit 230 are grounded.

[0111] Under the action of the first signal ENB2_CMP1, the second pull-up circuit 220 is turned off, so that the second pull-up circuit 220 can disconnect the pull-up of the second end of the current mirror 210, that is, the second pull-up circuit 220 disconnects the pull-up of the node C.

[0112] In some examples, the first pull-down circuit 120 or the second pull-down circuit 230 may include: a third inverter INV3 and a third transistor M3.

[0113] The input end of the third inverter INV3 is used to access the enable signal ENB1_CMP, or is electrically connected to the output end of the low voltage protection circuit 100, the output end of the third inverter INV3 is electrically connected to the control end of the third transistor M3, the first end of the third transistor M3 is electrically connected to the third end of the first signal output circuit 130, or the first end of the second transistor M2, and the second end of the third transistor M3 is grounded.

[0114] Since the working principles of the first pull-down circuit 120 and the second pull-down circuit 230 are similar, for the sake of convenience, the second pull-down circuit 230 is taken as an example for description.

[0115] The first signal ENB2_CMP1 is inverted and converted into the inverted first signal ENN2_CMP1 by the third inverter INV3, so that the second transistor M2 is turned off. In this way, the second pull-down circuit 230 disconnects the pull-down of the first end of the second transistor M2, that is, disconnects the pull-down of the node D. After the second pull-up circuit 220 and the second pull-down circuit 230 are turned off, it means that the comparison circuit 200 has sufficient current capacity, so that the comparison circuit 120 can obtain the comparison signal.

[0116] Since the current monitoring component 132 serves as a mirror current mirror of the current mirror 210, the current monitoring component 132 can monitor the current of the comparison circuit 120. In other words, the current monitoring component 132 can monitor the current of the first transistor Q1.

[0117] By comparing the input voltage VIN with the reference voltage, the current of the first transistor Q1 and the current of the second transistor Q2 can be compared. The reference voltage can be specifically calculated according to formula (2):

[0118] VREF=VBE2+2*ΔVBE*(r2+r3) / r1=VBE2+2*(VBE2-VBE1)*(r2+r3) / r1 (2)

[0119] Among them, VREF is the reference voltage, VBE2 is the voltage difference between the base and the emitter of the second transistor Q2, VBE1 is the voltage difference between the base and the emitter of the second transistor Q2, r1 is the resistance value of the first resistor R1, r2 is the resistance value of the second resistor R2, and r3 is the resistance value of the third resistor R3.

[0120] When the input voltage VIN is greater than the reference voltage VREF, the current of the second transistor Q2 is greater than the current of the first transistor Q1. In this way, the current of the first transistor Q1 is mirrored to the node C through the current mirror 210. In this way, the current of the first transistor Q1 can pull down the potential of the node C, so that the conduction current of the second transistor M2 is greater than the third current. Furthermore, the potential of the node D is pulled up, so that the comparison circuit 120 outputs a comparison signal.

[0121] Based on the description of the above embodiment, a possible implementation of the bandgap comparator 1000 is exemplified. Figure 1 and Figure 2 As shown, the bandgap comparator 1000 may further include: a signal output circuit 300 .

[0122] The first input end of the signal output circuit 300 is electrically connected to the output end of the comparison circuit 200, the second input end of the signal output circuit 300 is electrically connected to the output end of the low voltage protection circuit 100, and the output end of the signal output circuit 300 is used to output a protection signal VDD_V, and the protection signal VDD_V is used to indicate whether the power supply voltage VIN is undervoltage or overvoltage.

[0123] The protection signal VDD_V may include: an undervoltage protection signal VDD_UV1 and an overvoltage protection signal VDD_OV1 .

[0124] The signal output circuit 300 can obtain the protection signal VDD_V according to the comparison signal. Furthermore, when the power supply voltage VDD is undervoltage, the signal output circuit 300 can output the undervoltage protection signal VDD_UV1. Alternatively, when the power supply voltage VDD is overvoltage, the signal output circuit 300 can output the overvoltage protection signal VDD_OV1. Thus, it is possible to timely feedback whether the power supply voltage VIN is undervoltage or overvoltage.

[0125] Among them, since the principle of overvoltage protection of the power supply voltage VDD is similar to the principle of undervoltage protection of the power supply voltage VDD, for the convenience of explanation, the embodiments of the present application are explained by taking the undervoltage protection of the power supply voltage VDD as an example.

[0126] In summary, the signal output circuit can output a protection signal according to the comparison signal, and timely feedback whether the power supply voltage is undervoltage or overvoltage.

[0127] Based on the description of the above embodiment, a possible implementation of the signal output circuit 300 is exemplified. Figure 2 As shown, the signal output circuit 300 may include: a second signal amplifying component 310 and a logic processing component 320 .

[0128] The input end of the second signal amplifying component 310 is electrically connected to the output end of the comparison circuit 200, the output end of the second signal amplifying component 310 is electrically connected to the first input end of the logic processing component 320, the second input end of the logic processing component 320 is electrically connected to the output end of the low voltage protection circuit 100, and the output end of the logic processing component 320 is used to output the protection signal VDD_V.

[0129] In some examples, the second signal amplifying component 310 may include a second Schmitt trigger SMT2 , a fourth inverter INV4 , and a fifth inverter INV5 .

[0130] The input end of the second Schmitt trigger SMT2 is electrically connected to the output end of the comparison circuit 200, the output end of the second Schmitt trigger SMT2 is electrically connected to the input end of the fourth inverter INV4, the output end of the fourth inverter INV4 is electrically connected to the input end of the fifth inverter INV5, and the output end of the fifth inverter INV5 is used to output the protection signal VDD_V.

[0131] The second signal amplifying component 310 can amplify the comparison signal to obtain an amplified comparison signal UVLO. In addition, the second signal amplifying component 310 can transmit the amplified comparison signal UVLO to the logic processing component 320 so that the logic processing component 320 can obtain the amplified comparison signal UVLO.

[0132] In this way, the logic processing component 320 can perform a logic operation on the amplified comparison signal UVLO and the first signal ENB2_CMP1 to obtain the protection signal VDD_V, so that the signal output circuit 130 can obtain the protection signal VDD_V.

[0133] In some examples, the logic processing component 320 is a NOT gate device NAND1.

[0134] The protection signal VDD_V is, for example, a low level, ie, an undervoltage protection signal VDD_UV1 , indicating that the power supply voltage VDD is not undervoltage.

[0135] In summary, the second signal amplification component can amplify the comparison signal to obtain the amplified comparison signal, and transmit the amplified comparison signal to the logic processing component, so that the logic processing component can obtain the amplified comparison signal. In this way, the logic processing component can perform a logic operation on the amplified comparison signal and the first signal to obtain a protection signal. Thus, the signal output circuit can obtain the protection signal.

[0136] Based on the description of the above embodiment, a possible implementation of the comparison circuit 200 is exemplified. Figure 2 As shown, the comparison circuit 200 may further include: a fourth transistor M4.

[0137] The control end of the fourth transistor M4 is electrically connected to the output end of the second signal amplifying element 310 , the first end of the fourth transistor M4 is electrically connected between the second end of the second resistor R2 and the first end of the third resistor R3 , and the second end of the fourth transistor M4 is grounded.

[0138] The amplified comparison signal UVLO may be used as a hysteresis signal of the comparison circuit 120 . The amplified comparison signal UVLO controls the fourth transistor M4 to be turned on, thereby increasing the current capacity of the second diode Q2 .

[0139] When the enable signal ENB1_CMP is at a low level, that is, before the bandgap comparator 1000 works, the first pull-down circuit 120 is turned on, so that the first pull-down circuit 120 can pull down the potential of the node A, and the first pull-up circuit 110 is turned on, so that the first pull-up circuit 110 can pull up the potential of the node B, so that the potential of the node A is at a low level. In this way, the low voltage protection circuit 100 can obtain the second signal ENB2_CMP2, and transmit the second signal ENB2_CMP2 to the comparison circuit 200, so that the comparison circuit 200 can obtain the second signal ENB2_CMP2.

[0140] Under the action of the second signal ENB2_CMP2, the second pull-up circuit 220 is turned on, so that the second pull-up circuit 220 can pull up the potential of the node C, and the second pull-down circuit 230 is turned on, so that the second pull-down circuit 230 can pull down the potential of the node D, so that the potential of the node D is low. Then, the comparison circuit 200 can obtain the third signal, and transmit the third signal to the signal output circuit 300, so that the signal output circuit 300 can obtain the third signal. Thus, the signal output circuit 300 can obtain the high-level error signal VDD_UV2 according to the third signal.

[0141] In addition, based on the above content, it can be known that the four high-resistance points, namely, node A, node B, node C and node D, all have certain potentials before the bandgap comparator 1000 works.

[0142] When the enable signal ENB1_CMP is at a high level, that is, when the bandgap comparator 1000 needs to work, the first pull-down circuit 120 and the first pull-up circuit 110 are turned off. At this time, the current source outputs the first current Ib, so that the current output component 135 outputs the first current Ib. In this way, the first mirror component 133 can obtain the second current, so that the second current can pull down the potential of the node A, and the second mirror component 134 can obtain the third current, so that the third current pulls down the potential of the node D.

[0143] Since the power supply voltage VDD is low when the bandgap comparator 1000 needs to work, the current of the current mirror 210 is very small or even has no current capability. Therefore, the fourth current obtained by the current monitoring component 132 is also very small or even zero, so that the potential of the node A is still at a low level. In this way, the low voltage protection circuit 100 can obtain the second signal ENB2_CMP2 and transmit the second signal ENB2_CMP2 to the comparison circuit 200, so that the comparison circuit 200 can obtain the second signal ENB2_CMP2.

[0144] Under the action of the second signal ENB2_CMP2, the second pull-up circuit 220 is turned on, so that the second pull-up circuit 220 can pull up the potential of the node C, and the second pull-down circuit 230 is turned on, so that the second pull-down circuit 230 can pull down the potential of the node D, so that the potential of the node D is low. Then, the comparison circuit 200 can obtain the third signal, and transmit the third signal to the signal output circuit 300, so that the signal output circuit 300 can obtain the third signal. Thus, the signal output circuit 300 can obtain the high-level error signal VDD_UV2 according to the third signal, which can prevent the output signal of the bandgap comparator 1000 from being flipped by mistake.

[0145] The second signal ENB2_CMP2 is used to indicate that the comparison circuit 200 does not work. The error signal VDD_UV2 is used to indicate that the power supply voltage VIN is lower than a preset voltage.

[0146] Finally, it should be noted that the above embodiments are only specific implementation methods of the present application, but the protection scope of the present application is not limited thereto, and any changes or substitutions within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A bandgap comparator, It is characterized in that The bandgap comparator comprises: a comparison circuit and a low voltage protection circuit; The input end of the low voltage protection circuit is used to access an enable signal, and the enable signal is used to enable the low voltage protection circuit. The first end of the low voltage protection circuit is electrically connected to the first end of the comparison circuit, and the second end of the low voltage protection circuit is electrically connected to the second end of the comparison circuit. The output end of the low voltage protection circuit is electrically connected to the third end and the fourth end of the comparison circuit respectively. The input end of the comparison circuit is used to access an input voltage, and the input voltage is related to the power supply voltage. The output end of the comparison circuit is used to output a comparison signal, and the comparison signal is used to indicate whether the power supply voltage is within a preset voltage range. The low voltage protection circuit is used to transmit a first signal to the comparison circuit when it is detected that the current of the comparison circuit is greater than a preset current under the action of the enable signal, wherein the first signal is used to enable the comparison circuit; The comparison circuit is used to compare the input voltage and a reference voltage according to the first signal to obtain the comparison signal.

2. The bandgap comparator according to claim 1, It is characterized in that The low voltage protection circuit comprises: a first pull-up circuit, a first pull-down circuit and a first signal output circuit; The first end of the first pull-up circuit is electrically connected to the first end of the first signal output circuit, the control end of the first pull-up circuit and the control end of the first pull-down circuit are both used to access the enable signal, the second end of the first pull-up circuit and the second end of the first signal output circuit are both electrically connected to the first end of the comparison circuit, the third end of the first signal output circuit is electrically connected to the first end of the first pull-down circuit, the fourth end of the first signal output circuit is electrically connected to the second end of the comparison circuit, the fifth end of the first signal output circuit is electrically connected to the third end of the comparison circuit, and the sixth end of the first signal output circuit and the second end of the first pull-down circuit are both grounded; The first pull-up circuit is used to disconnect the pull-up of the first signal output circuit when the enable signal is at a high level; The first pull-down circuit is used to disconnect the pull-down of the first signal output circuit when the enable signal is at a high level; The first signal output circuit is used to output the first signal when the current of the comparison circuit is greater than a preset current after the pull-up of the first pull-up circuit and the pull-down of the first pull-down circuit are both disconnected.

3. The bandgap comparator according to claim 2, It is characterized in that The first signal output circuit comprises: a first signal amplifying component, a current monitoring component, a first mirror component, a second mirror component and a current output component; The first end of the current monitoring component is electrically connected to the first end of the first pull-up circuit, the second end of the current monitoring component is electrically connected to the first end of the comparison circuit, the third end of the current monitoring component is electrically connected to the first end of the first mirror component, the first end of the first pull-down circuit and the input end of the first signal amplifying component are both electrically connected between the third end of the current monitoring component and the first end of the first mirror component, the second end of the first mirror component is electrically connected to the first end of the current output component and the second end of the second mirror component respectively, the first end of the second mirror component is electrically connected to the second end of the comparison circuit, the output end of the first signal amplifying component is electrically connected to the third end of the comparison circuit, and the third end of the first mirror component, the second end of the current output component and the third end of the second mirror component are all grounded; The current output component is used to output a first current, and the first current is used as a pull-down current; The first mirror component is used to mirror the first current to obtain a second current, and transmit the second current to the first signal amplifying component, wherein the second current is used to pull down the potential of the input terminal of the first signal amplifying component; The second mirror component is used to mirror the first current to obtain a third current, and transmit the third current to the comparison circuit, wherein the third current is used to pull down the potential of the second end of the comparison circuit; The current monitoring component is used to monitor the current of the comparison circuit to obtain a fourth current, and transmit the fourth current to the first signal amplifying component, wherein the fourth current is used to pull up the potential of the input terminal of the first signal amplifying component; The first signal amplifying component is used to obtain the first signal when the fourth current is greater than the second current.

4. The bandgap comparator according to claim 3, It is characterized in that The first signal amplifying component includes: a first Schmitt trigger, a first inverter and a second inverter; The input end of the first Schmitt trigger is electrically connected between the third end of the current monitoring component and the first end of the first mirror component, the output end of the first Schmitt trigger is electrically connected to the input end of the first inverter, the output end of the first inverter is electrically connected to the input end of the second inverter, and the output end of the second inverter is electrically connected to the third end of the comparison circuit.

5. The bandgap comparator according to claim 3, It is characterized in that The current output component comprises: a current source and a first transistor; The output end of the current source is electrically connected to the first end of the first transistor, the control end of the first transistor and the second end of the first mirror component respectively, and the second end of the first transistor is grounded.

6. The bandgap comparator according to claim 2, It is characterized in that The comparison circuit comprises: a first resistor, a second resistor, a third resistor, a current mirror, a first triode, a second triode, a second pull-up circuit, a second pull-down circuit and a second transistor; The first end of the first transistor is electrically connected to the first end of the current mirror, the first end of the low voltage protection circuit is electrically connected between the first end of the first transistor and the first end of the current mirror, the second end of the current mirror is electrically connected to the first end of the second transistor, the third end of the current mirror and the first end of the second pull-up circuit are both electrically connected to the second end of the second transistor, the second end of the second pull-up circuit and the control end of the second transistor are both electrically connected between the second end of the current mirror and the first end of the second transistor, the first end of the second transistor is electrically connected to the first end of the second pull-down circuit, the control end of the second pull-up circuit and the control end of the second pull-down circuit are both electrically connected to the low voltage protection circuit. The output end of the low voltage protection circuit is electrically connected to the output end of the low voltage protection circuit, the second end of the low voltage protection circuit is electrically connected between the first end of the second transistor and the first end of the second pull-down circuit, the second end of the first triode and the second end of the second triode are both used to access the input voltage, the third end of the first triode is electrically connected to the first end of the first resistor, the second end of the first resistor is electrically connected to the third end of the second triode, the first end of the second resistor is electrically connected between the second end of the first resistor and the third end of the second triode, the second end of the second resistor is electrically connected to the first end of the third resistor, and the second end of the third resistor and the second end of the second pull-down circuit are grounded; The second pull-up circuit is used to disconnect the pull-up of the second end of the current mirror according to the first signal, so that the comparison circuit obtains the comparison signal; The second pull-down circuit is used to disconnect the pull-down of the first end of the second transistor according to the first signal, so that the comparison circuit obtains the comparison signal.

7. The bandgap comparator according to claim 6, It is characterized in that The first pull-down circuit or the second pull-down circuit comprises: a third inverter and a third transistor; The input end of the third inverter is used to access the enable signal, or is electrically connected to the output end of the low-voltage protection circuit, the output end of the third inverter is electrically connected to the control end of the third transistor, the first end of the third transistor is electrically connected to the third end of the first signal output circuit, or the first end of the second transistor, and the second end of the third transistor is grounded.

8. The bandgap comparator according to any one of claims 1 to 7, It is characterized in that The bandgap comparator further includes: a signal output circuit; The first input end of the signal output circuit is electrically connected to the output end of the comparison circuit, the second input end of the signal output circuit is electrically connected to the output end of the low voltage protection circuit, and the output end of the signal output circuit is used to output a protection signal, and the protection signal is used to indicate whether the power supply voltage is undervoltage or overvoltage; The signal output circuit is used to output the protection signal according to the comparison signal.

9. The bandgap comparator according to claim 8, It is characterized in that The signal output circuit includes: a second signal amplification component and a logic processing component; The input end of the second signal amplifying component is electrically connected to the output end of the comparison circuit, the output end of the second signal amplifying component is electrically connected to the first input end of the logic processing component, the second input end of the logic processing component is electrically connected to the output end of the low voltage protection circuit, and the output end of the logic processing component is used to output the protection signal; The second signal amplifying component is used to amplify the comparison signal to obtain the amplified comparison signal, and transmit the amplified comparison signal to the logic processing component; The logic processing component is used to perform a logic operation on the amplified comparison signal and the first signal to obtain the protection signal.

10. The bandgap comparator according to claim 9, It is characterized in that The second signal amplifying component includes: a second Schmitt trigger, a fourth inverter and a fifth inverter; The input end of the second Schmitt trigger is electrically connected to the output end of the comparison circuit, the output end of the second Schmitt trigger is electrically connected to the input end of the fourth inverter, the output end of the fourth inverter is electrically connected to the input end of the fifth inverter, and the output end of the fifth inverter is used to output the protection signal.

11. The bandgap comparator according to claim 9, It is characterized in that The comparison circuit further includes: a fourth transistor; The control end of the fourth transistor is electrically connected to the output end of the second signal amplifying component, the first end of the fourth transistor is electrically connected between the second end of the second resistor and the first end of the third resistor, and the second end of the fourth transistor is grounded.

12. The bandgap comparator according to claim 8, It is characterized in that The low voltage protection circuit is further configured to transmit a second signal to the comparison circuit when the current of the comparison circuit is less than or equal to the preset current when the enable signal is at a high level, or when the enable signal is at a low level, wherein the second signal is used to indicate that the comparison circuit is not working; The comparison circuit is further configured to stop monitoring the power supply voltage under the action of the second signal, obtain a third signal, and transmit the third signal to the signal output circuit; The signal output circuit is further used to obtain the error signal according to the third signal, and the error signal is used to indicate that the power supply voltage is lower than a preset voltage.

13. A power management system, It is characterized in that include: The bandgap comparator according to any one of claims 1 to 12.

14. A chip, It is characterized in that include: The power management system as claimed in claim 13.

15. An electronic device, It is characterized in that include: The chip as claimed in claim 14.

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