Current comparison circuit, driving chip and electronic equipment

Abstract

The invention provides a current comparison circuit, a driving chip and electronic equipment. The current comparison circuit may include a positive feedback circuit and an input circuit. When the mirror current is greater than the reference current, the input circuit can pull up the potential of the output end of the input circuit, so that the potential of the second end of the positive feedback circuit is also pulled up. Therefore, under the action of the second end of the positive feedback circuit for increasing the potential, the positive feedback circuit can form positive feedback, so that the potential of the second end of the positive feedback circuit is rapidly increased. Therefore, the positive feedback circuit can quickly pull down the potential of the control end of the high-side power tube to the potential of the first voltage, so that the high-side power tube is quickly turned off. Therefore, the current comparison circuit can quickly turn off the high-side power tube, thereby preventing the high-side power tube from generating large current, and protecting the high-side power tube.

Description

Technical Field

[0001] The present application relates to the technical field of integrated circuits, and in particular to a current comparison circuit, a driver chip and an electronic device. Background Art

[0002] In chips such as motor drive and high-side drive in the field of automotive electronics, the voltage difference between the gate terminal GATE1 and the source terminal OUT1 of the high-side power tube is pumped to between 10V and 15V through a charge pump, so that the chip can meet the driving requirements of the high-side power tube.

[0003] In the related art, the driving circuit can generally include: a current limiting operational amplifier circuit, a high-side power tube and a mirror switch tube. The mirror switch tube copies the current of the high-side power tube when it is turned on, that is, the load current, so that the mirror switch tube can generate a mirror current. In this way, the mirror current can flow into the negative input terminal of the current limiting operational amplifier circuit, and the reference current can flow into the positive input terminal of the current limiting operational amplifier circuit. Furthermore, when the load current is too large, that is, when the mirror current is greater than the reference current, the current limiting operational amplifier circuit is triggered. Thereby, the current limiting operational amplifier circuit can clamp the gate terminal of the high-side power tube so that the load current can be limited within the current limiting value.

[0004] However, in the related art, the response speed of the current limiting loop composed of the current limiting operational amplifier circuit, the high-side power tube and the mirror switch tube is slow, so that a large current may appear in the high-side power tube, resulting in the risk of the high-side power tube being burned. Summary of the invention

[0005] The present application provides a current comparison circuit, a driver chip and an electronic device, which can quickly shut down the high-side power tube when the load current is too large, thereby avoiding the high-side power tube from having a large current and eliminating the risk of the high-side power tube being burned, thereby protecting the high-side power tube.

[0006] In a first aspect, the present application provides a current comparison circuit, which includes: a positive feedback circuit and an input circuit.

[0007] The first input end of the input circuit is used to access a mirror current, and the mirror current is used to characterize the magnitude of the current when the high-side power tube is turned on. The second input end of the input circuit is used to access a reference current. The output end of the input circuit is electrically connected to the first end of the positive feedback circuit. The first end of the input circuit and the second end of the positive feedback circuit are both used to access a working current, and the working current is used to operate the current comparison circuit. The third end of the positive feedback circuit is electrically connected to the control end of the high-side power tube.

[0008] The input circuit is used to pull up the potential of the output end of the input circuit when the mirror current is greater than the reference current, so as to pull up the potential of the second end of the positive feedback circuit.

[0009] The positive feedback circuit is used to form positive feedback under the action of the second end of the positive feedback circuit that pulls up the potential, so as to quickly pull the potential of the control end of the high-side power tube down to the potential of the first voltage, so that the high-side power tube is turned off.

[0010] By means of the current comparison circuit provided in the first aspect, when the mirror current is greater than the reference current, the input circuit can pull up the potential of the output end of the input circuit, so that the potential of the second end of the positive feedback circuit is also pulled up. In this way, under the action of the second end of the positive feedback circuit that pulls up the potential, the positive feedback circuit can form positive feedback, so that the potential of the second end of the positive feedback circuit rises rapidly. In this way, the positive feedback circuit can quickly pull down the potential of the control end of the high-side power tube to the potential of the first voltage, so that the high-side power tube is quickly turned off. Thus, the current comparison circuit can quickly turn off the high-side power tube, avoid the occurrence of large current in the high-side power tube, and protect the high-side power tube.

[0011] In a possible design, the positive feedback circuit is further used to release the positive feedback after the control end of the high-side power tube is completely discharged, so that the current comparison circuit can re-perform overcurrent detection.

[0012] Based on this, after the control end of the high-side power tube is completely discharged, the positive feedback circuit can release the positive feedback, so that the current comparison circuit will not be locked. Thus, the current comparison circuit can perform overcurrent detection again.

[0013] In one possible design, the positive feedback circuit includes: a clamping circuit and a latching circuit.

[0014] The first end of the latch circuit is electrically connected to the output end of the input circuit, the second end of the latch circuit and the first end of the clamp circuit are both used to access the working current, the third end of the latch circuit is electrically connected to the control end of the high-side power tube, and the fourth end of the latch circuit is used to access the bias voltage, and the bias voltage is used to determine the working state of the transistor in the latch circuit.

[0015] The latch circuit is used to pull up the potential of the second end of the latch circuit under the action of the output end of the input circuit with a high potential, so as to pull down the potential of the fourth end of the latch circuit, so that the positive feedback is formed.

[0016] The clamping circuit is used to clamp the potential of the second end of the latch circuit.

[0017] Based on this, under the action of the output end of the input circuit that pulls up the potential, the latch circuit can pull up the potential of the second end of the latch circuit, so that the potential of the fourth end of the latch circuit is pulled down. In this way, the latch circuit can form the positive feedback, so that the potential of the second end of the latch circuit rises rapidly until the potential of the second end of the latch circuit is clamped by the clamp circuit, which can prevent the potential of the second end of the latch circuit from rising to the second voltage. Thus, the positive feedback circuit can quickly pull down the potential of the control end of the high-side power tube to the potential of the first voltage, so that the high-side power tube is quickly turned off.

[0018] In one possible design, the latch circuit includes: a first transistor, a second transistor, a third transistor, and a fourth transistor.

[0019] The first end of the first transistor is electrically connected to the output end of the input circuit, the control end of the first transistor is used to access the bias voltage, the second end of the first transistor and the control end of the second transistor are both used to access the working current, the second end of the second transistor is electrically connected to the control end of the high-side power tube, the first end of the second transistor is respectively electrically connected to the second end of the third transistor, the control end of the third transistor and the control end of the fourth transistor, the second end of the fourth transistor is electrically connected to the control end of the first transistor, and the first end of the third transistor and the first end of the fourth transistor are both used to access the first voltage.

[0020] Based on this, under the action of the output end of the input circuit that pulls up the potential, the potential of the second end of the first transistor is pulled up, so that the second transistor is turned on. In this way, under the action of the turned-on second transistor, the potential of the control end of the third transistor is pulled up, and when the potential of the control end of the third transistor is higher than the threshold voltage of the third transistor, the third transistor is turned on. In this way, the second transistor and the third transistor are both turned on, so that the first voltage pulls current from the control end of the high-side power tube. At the same time, when the second transistor and the third transistor are both turned on, the fourth transistor is turned on, so that the potential of the control end of the first transistor is pulled down, so that the positive feedback is formed. As a result, the potential of the second end of the first transistor rises rapidly, so that the potential of the second end of the latch circuit rises rapidly.

[0021] In a possible design, the clamping circuit includes: a first P-type MOS transistor, a second P-type MOS transistor, a first N-type MOS transistor, and a second N-type MOS transistor.

[0022] The first end of the first P-type MOS tube is used to access the working current, the second end of the first P-type MOS tube and the control end of the first P-type MOS tube are both electrically connected to the first end of the second P-type MOS tube, the second end of the second P-type MOS tube and the control end of the second P-type MOS tube are both electrically connected to the second end of the first N-type MOS tube, the second end of the first N-type MOS tube is also electrically connected to the control end of the first N-type MOS tube, the first end of the first N-type MOS tube is respectively electrically connected to the second end of the second N-type MOS tube and the control end of the second N-type MOS tube, and the first end of the second N-type MOS tube is used to access a first voltage.

[0023] Based on this, under the action of the working current, the first P-type MOS transistor, the second P-type MOS transistor, the first N-type MOS transistor and the second N-type MOS transistor are all turned on. In this way, after the latch circuit can form positive feedback, the potential of the second end of the latch circuit can be clamped by the first P-type MOS transistor, the second P-type MOS transistor, the first N-type MOS transistor and the second N-type MOS transistor. Thus, the clamping circuit can clamp the potential of the second end of the latch circuit, and can prevent the potential of the second end of the latch circuit from rising to the second voltage.

[0024] In one possible design, the input circuit includes: a fifth transistor, a sixth transistor, a first resistor, and a second resistor.

[0025] The first end of the first resistor and the first end of the second resistor are both used to access the first voltage, the second end of the first resistor and the first end of the fifth transistor are both used to access the mirror current, the second end of the fifth transistor is electrically connected to the first end of the positive feedback circuit, the control end of the fifth transistor is electrically connected to the control end of the sixth transistor, the second end of the second resistor and the first end of the sixth transistor are both used to access the reference current, and the second end of the sixth transistor is used to access the working current.

[0026] Based on this, when the mirror current is greater than the reference current, the potential of the second end of the fifth transistor is increased by increasing the potential of the first end of the fifth transistor. In this way, under the action of the second end of the fifth transistor with increased potential, the potential of the second end of the latch circuit is increased. Thus, under the action of the output end of the input circuit with increased potential, the latch circuit can increase the potential of the second end of the latch circuit.

[0027] In one possible design, the current comparison circuit also includes: a seventh transistor and a third resistor.

[0028] The second end of the seventh transistor is used to access the working current, the control end of the seventh transistor is electrically connected to the fourth end of the latch circuit, the first end of the seventh transistor is electrically connected to the first end of the third resistor, and the second end of the third resistor is used to access the first voltage.

[0029] Based on this, the bias voltage can be provided to the first transistor through the seventh transistor and the third resistor, so that the working state of the first transistor changes, so that the latch circuit can work.

[0030] In one possible design, the current comparison circuit also includes: an operating current output circuit.

[0031] The power supply end of the working current output circuit is used to access the second voltage, and the output end of the working current output circuit is electrically connected to the first end of the input circuit.

[0032] The working current output circuit is used to output the working current.

[0033] Based on this, the working current can be outputted through the working current output circuit, so that the input circuit and the positive feedback circuit can obtain the working current. Thus, the current comparison circuit can operate.

[0034] In one possible design, the working current output circuit includes: a first current mirror tube, a second current mirror tube, a third current mirror tube, a fourth current mirror tube, a fifth current mirror tube, a sixth current mirror tube, a seventh current mirror tube, an eighth current mirror tube and a current source.

[0035] The first end of the first current mirror tube, the first end of the third current mirror tube, the first end of the fifth current mirror tube and the first end of the seventh current mirror tube are all used to connect to the second voltage. The control end of the first current mirror tube is electrically connected to the second end of the first current mirror tube, the first end of the second current mirror tube, the control end of the third current mirror tube, the control end of the fifth current mirror tube and the control end of the seventh current mirror tube respectively. The second end of the second current mirror tube is electrically connected to the first end of the current source, the control end of the second current mirror tube, the control end of the fourth current mirror tube, the control end of the sixth current mirror tube and the control end of the eighth current mirror tube respectively. The second end of the third current mirror tube is electrically connected to the first end of the fourth current mirror tube, the second end of the fifth current mirror tube is electrically connected to the first end of the sixth current mirror tube, the second end of the seventh current mirror tube is electrically connected to the first end of the eighth current mirror tube, the second end of the fourth current mirror tube is electrically connected to the first end of the input circuit, the second end of the eighth current mirror tube is electrically connected to the second end of the positive feedback circuit, the second end of the sixth current mirror tube is used to output the working current, and the second end of the current source is grounded.

[0036] The current source is used to output a reference current so that the working current output circuit can output the working current.

[0037] Based on this, after the second current mirror tube obtains the reference current, the first current mirror tube, the second current mirror tube, the third current mirror tube and the fourth current mirror tube are used so that the second end of the fourth current mirror tube can output the working current. The third current mirror tube, the fourth current mirror tube, the fifth current mirror tube and the sixth current mirror tube are used so that the second end of the sixth current mirror tube can output the working current. The fifth current mirror tube, the sixth current mirror tube, the seventh current mirror tube and the eighth current mirror tube are used so that the second end of the eighth current mirror tube can output the working current. In this way, the working current output circuit can output the working current, so that the input circuit and the positive feedback circuit can obtain the working current. Thus, the current comparison circuit can operate.

[0038] In a second aspect, the present application provides a driver chip, comprising: a driver, a high-side power tube, a mirror circuit, and a current comparison circuit in the above-mentioned first aspect and any possible design of the first aspect.

[0039] The input end of the driver is used to access a driving signal, and the driving signal is used to drive the high-side power tube to be turned on or off. The output end of the driver is electrically connected to the control end of the high-side power tube. The first end of the high-side power tube and the first end of the mirror circuit are both used to access a power supply voltage. The second end of the mirror circuit is electrically connected to the first input end of the current comparison circuit. The second input end of the current comparison circuit is used to access a reference current. The output end of the current comparison circuit and the control end of the mirror circuit are both electrically connected between the output end of the driver and the control end of the high-side power tube. The power supply end of the current comparison circuit is used to access a second voltage. The ground end of the current comparison circuit is used to access a first voltage. The second end of the high-side power tube is grounded. The current comparison circuit is located in a voltage domain between the second voltage and the first voltage.

[0040] The driver is used to drive the high-side power tube to conduct according to the driving signal.

[0041] The mirror circuit is used to mirror the current of the high-side power tube when it is turned on to obtain a mirror current.

[0042] The current comparison circuit is used to obtain the mirror current from the mirror circuit, and when the mirror current is greater than the reference current, quickly pull down the potential of the control end of the high-side power tube to the potential of the first voltage to turn off the high-side power tube.

[0043] The beneficial effects of the driver chip provided in the second aspect and each possible design of the second aspect can be referred to the beneficial effects brought about by the first aspect and each possible implementation method of the first aspect, which will not be repeated here.

[0044] In a third aspect, the present application provides an electronic device, comprising: the driving chip in the above-mentioned second aspect.

[0045] The above description is only an overview of the technical solution of the embodiment of the present application. In order to more clearly understand the technical means of the embodiment of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the embodiment of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solutions of the embodiments of the present application, a brief introduction will be given below to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0047] Figure 1It is a structural schematic diagram of a driving circuit in the related art;

[0048] Figure 2 A schematic diagram of the structure of a driver chip provided in one embodiment of the present application;

[0049] Figure 3 A schematic diagram of the structure of a current comparison circuit provided in one embodiment of the present application. DETAILED DESCRIPTION

[0050] 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.

[0051] 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.

[0052] 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.

[0053] Reference Figure 1 , Figure 1 FIG. 1 is a schematic diagram of the structure of a driving circuit in the related art. Figure 1As shown, the driving circuit in the related art may generally include: a current limiting operational amplifier circuit, a high-side power tube MD1 and a mirror switch tube MCL1. The mirror switch tube MCL1 can, for example, copy the load current Iload1 in a ratio of 1:N, so that the mirror switch tube MCL1 can generate a mirror current ICL1. In this way, the mirror current ICL1 can flow into the negative phase input terminal of the current limiting operational amplifier circuit, and the reference current Iref1 can flow into the positive phase input terminal of the current limiting operational amplifier circuit. Furthermore, when the load current Iload1 is too large, that is, when the mirror current ICL1 is greater than the reference current Iref1, the current limiting operational amplifier circuit is triggered. Thus, the current limiting operational amplifier circuit can clamp the gate terminal GATE1 of the high-side power tube MD1, so that the load current Iload1 can be limited within the current limiting value.

[0054] However, the response speed of the current limiting loop composed of the current limiting operational amplifier circuit, the high-side power tube and the mirror switch tube is slow, so that a large current may appear in the high-side power tube MD1, resulting in the risk of burning the high-side power tube MD1.

[0055] In order to solve the above problems, the present application provides a current comparison circuit, a driving chip and an electronic device.

[0056] The current comparison circuit 100 may be a chip or a circuit module.

[0057] In this application, electronic devices may include, but are not limited to: household appliances, automotive electronics, industrial automation, and smart homes.

[0058] Reference Figure 2 , Figure 2 This is a schematic diagram of the structure of a driver chip provided in one embodiment of the present application. Figure 2 As shown, the driver chip 1000 may include: a driver 200 , a high-side power transistor MD2 , a mirror circuit 300 and a current comparison circuit 100 .

[0059] The input end of the driver 200 is used to access the drive signal EN_DRV2, and the drive signal EN_DRV2 is used to drive the high-side power tube MD2 to be turned on or off. The output end of the driver 200 is electrically connected to the control end GATE2 of the high-side power tube MD2. The first end of the high-side power tube MD2 and the first end of the mirror circuit 300 are both used to access the power supply voltage VS2. The second end of the mirror circuit 300 is electrically connected to the first input end of the current comparison circuit 100. The second input end of the current comparison circuit 100 is used to access the reference current Iref2. The output end of the current comparison circuit 100 and the control end of the mirror circuit 300 are both electrically connected between the output end of the driver 200 and the control end GATE2 of the high-side power tube MD2. The power supply end of the current comparison circuit 100 is used to access the second voltage VCP2. The ground end of the current comparison circuit 100 is used to access the first voltage VOUT2. The second end of the high-side power tube MD2 is grounded. The current comparison circuit 100 is located in a voltage domain between the second voltage VCP2 and the first voltage VOUT2.

[0060] The reference current Iref2 is provided by a reference current source, for example.

[0061] The first end of the reference current source is used to access the second voltage VCP2, and the second end of the reference current source is electrically connected to the second input end of the current comparison circuit 100. That is, the reference current Iref2 is provided by the second voltage VCP2.

[0062] Figure 2 In the figure, the input end of the driver 200 is recorded as 1, the output end of the driver 200 is recorded as 2, the first end of the high-side power tube MD2 is recorded as 1, the second end of the high-side power tube MD2 is recorded as 2, the first end of the mirror circuit 300 is recorded as 1, the second end of the mirror circuit 300 is recorded as 2, the first input end of the current comparison circuit 100 is recorded as 1, the second input end of the current comparison circuit 100 is recorded as 2, and the output end of the current comparison circuit 100 is recorded as 3.

[0063] In some examples, the mirror circuit 300 may be a current mirror tube MCL2 or a current mirror tube group composed of multiple current mirror tubes MCL2, which is not specifically limited in the present embodiment. For ease of description, the present embodiment is described by taking a current mirror tube MCL2 as an example.

[0064] For example, when the driving signal EN_DRV2 is at a high level, the driver 200 can drive the high-side power tube MD2 to turn on according to the driving signal EN_DRV2. For another example, when the driving signal EN_DRV2 is at a low level, the driver 200 can drive the high-side power tube MD2 to turn off according to the driving signal EN_DRV2.

[0065] The driver 200 can drive the high-side power tube MD2 to turn on according to the driving signal EN_DRV2. In this way, the mirror circuit 300, for example, mirrors the current of the high-side power tube MD2 when it is turned on, that is, the load current Iload2, at a ratio of 1:N, so that the mirror circuit 300 can obtain the mirror current ICL2. In addition, the mirror circuit 300 can transmit the mirror current ICL2 to the current comparison circuit 100, so that the current comparison circuit 100 can obtain the mirror current ICL2. Furthermore, when the mirror current ICL2 is greater than the reference current Iref2, that is, when the mirror current ICL2 reaches the overcurrent point, the current comparison circuit 100 can quickly pull down the potential of the control terminal GATE2 of the high-side power tube MD2 to the potential of the first voltage VOUT2. Thereby, the current comparison circuit 100 can quickly turn off the high-side power tube MD2 to avoid a large current in the high-side power tube MD2, so as to protect the high-side power tube MD2.

[0066] In summary, the driver can drive the high-side power tube to turn on according to the driving signal. In this way, the mirror circuit can mirror the current of the high-side power tube when it is turned on, so that the mirror circuit can obtain the mirror current. In this way, the current comparison circuit can obtain the mirror current from the mirror circuit. Moreover, when the mirror current is greater than the reference current, the current comparison circuit can quickly pull down the potential of the control end of the high-side power tube to the potential of the first voltage. Thus, the current comparison circuit can quickly turn off the high-side power tube to avoid large current in the high-side power tube to protect the high-side power tube.

[0067] Reference Figure 3 , Figure 3 Shows Figure 2 A schematic diagram of the structure of a current comparison circuit. Figure 3 As shown, the current comparison circuit 100 may include: a positive feedback circuit 120 and an input circuit 110 .

[0068] The first input terminal of the input circuit 110 is used to access the mirror current ICL2, and the mirror current ICL2 is used to characterize the magnitude of the current when the high-side power tube MD2 is turned on. The second input terminal of the input circuit 110 is used to access the reference current Iref2. The output terminal of the input circuit 110 is electrically connected to the first terminal of the positive feedback circuit 120. The first terminal of the input circuit 110 and the second terminal of the positive feedback circuit 120 are both used to access the working current, and the working current is used to operate the current comparison circuit 100. The third terminal of the positive feedback circuit 120 is electrically connected to the control terminal GATE2 of the high-side power tube MD2.

[0069] The positive feedback circuit 120 and the input circuit 110 may be arranged separately or integratedly.

[0070] Figure 3In the figure, the first input terminal of the input circuit 110 is marked as 1, the second input terminal of the input circuit 110 is marked as 2, the output terminal of the input circuit 110 is marked as 3, the first terminal of the input circuit 110 is marked as 4, the first terminal of the positive feedback circuit 120 is marked as 1, the second terminal of the positive feedback circuit 120 is marked as 2, and the third terminal of the positive feedback circuit 120 is marked as 3.

[0071] When the mirror current ICL2 is greater than the reference current Iref2, that is, when the load current ILoad2 is too large, the input circuit 110 can pull up the potential of the output end of the input circuit 110, so that the potential of the second end of the positive feedback circuit 120 is also pulled up. In this way, under the action of the second end of the positive feedback circuit 120 that pulls up the potential, the positive feedback circuit 120 triggers the latch latch, that is, the positive feedback circuit 120 can form positive feedback, so that the potential of the second end of the positive feedback circuit 120 rises rapidly. In this way, the positive feedback circuit 120 can quickly pull down the potential of the control end GATE2 of the high-side power tube MD2 to the potential of the first voltage VOUT2, so that the high-side power tube MD2 is quickly turned off. Thereby, the current comparison circuit 100 can quickly turn off the high-side power tube MD2, avoid the high-side power tube MD2 from having a large current, and protect the high-side power tube MD2.

[0072] In some examples, when the high-side power tube MD2 is turned off, the control terminal GATE2 of the high-side power tube MD2 will discharge. In this way, after the control terminal GATE2 of the high-side power tube MD2 is completely discharged, the positive feedback circuit 120 can trigger the unlocking de-latch, that is, release the positive feedback, so that the current comparison circuit 100 will not be locked. Therefore, the current comparison circuit 100 can re-perform overcurrent detection.

[0073] The current comparison circuit, driver chip and electronic device provided by the present application, when the mirror current is greater than the reference current, the input circuit can pull up the potential of the output end of the input circuit, so that the potential of the second end of the positive feedback circuit is also pulled up. In this way, under the action of the second end of the positive feedback circuit that pulls up the potential, the positive feedback circuit can form positive feedback, so that the potential of the second end of the positive feedback circuit rises rapidly. In this way, the positive feedback circuit can quickly pull down the potential of the control end of the high-side power tube to the potential of the first voltage, so that the high-side power tube is quickly turned off. Thereby, the current comparison circuit can quickly turn off the high-side power tube to avoid large current in the high-side power tube to protect the high-side power tube.

[0074] Based on the description of the above embodiment, a possible implementation of the positive feedback circuit 120 is exemplified. Figure 3 As shown, the positive feedback circuit 120 may include: a clamp circuit 121 and a latch circuit 122 .

[0075] The first end of the latch circuit 122 is electrically connected to the output end of the input circuit 110, the second end A of the latch circuit 122 and the first end of the clamp circuit 121 are both used to connect to the working current, the third end of the latch circuit 122 is electrically connected to the control end GATE2 of the high-side power tube MD2, and the fourth end C of the latch circuit 122 is used to connect to the bias voltage, and the bias voltage is used to determine the working state of the transistor in the latch circuit 122.

[0076] The working state may include: a cut-off state of the transistor, a saturation state of the transistor, and an amplification state of the transistor.

[0077] The first end of the latch circuit 122 is the first end of the positive feedback circuit 120 , the second end A of the latch circuit 122 is the second end of the positive feedback circuit 120 , and the third end of the latch circuit 122 is the third end of the positive feedback circuit 120 .

[0078] Under the action of the output end of the input circuit 110 that pulls up the potential, the latch circuit 122 can pull up the potential of the second end A of the latch circuit 122, so that the potential of the fourth end C of the latch circuit 122 is pulled down. In this way, the latch circuit 122 can form positive feedback, so that the potential of the second end A of the latch circuit 122 rises rapidly, until the potential of the second end A of the latch circuit 122 is clamped by the clamp circuit 121, which can prevent the potential of the second end A of the latch circuit 122 from rising to the second voltage VCP2. Thus, the positive feedback circuit 120 can quickly pull down the potential of the control end GATE2 of the high-side power tube MD2 to the potential of the first voltage VOUT2, so that the high-side power tube MD2 is quickly turned off.

[0079] In summary, under the action of the output end of the input circuit that pulls up the potential, the latch circuit can pull up the potential of the second end of the latch circuit, so that the potential of the fourth end of the latch circuit is pulled down. In this way, the latch circuit can form positive feedback, so that the potential of the second end of the latch circuit rises rapidly, until the potential of the second end of the latch circuit is clamped by the clamp circuit, which can prevent the potential of the second end of the latch circuit from rising to the second voltage. Thus, the positive feedback circuit can quickly pull down the potential of the control end of the high-side power tube to the potential of the first voltage, so that the high-side power tube is quickly turned off.

[0080] Based on the description of the above embodiment, a possible implementation of the latch circuit 122 is exemplified. Figure 3 As shown, the latch circuit 122 may include: a first transistor M1, a second transistor M2, a third transistor M3 and a fourth transistor M4.

[0081] The first end of the first transistor M1 is electrically connected to the output end of the input circuit 110, the control end of the first transistor M1 is used to access the bias voltage, the second end of the first transistor M1 and the control end of the second transistor M2 are both used to access the working current, the second end of the second transistor M2 is electrically connected to the control end GATE2 of the high-side power tube MD2, the first end of the second transistor M2 is electrically connected to the second end of the third transistor M3, the control end B of the third transistor M3 and the control end of the fourth transistor M4 respectively, the second end of the fourth transistor M4 is electrically connected to the control end of the first transistor M1, and the first end of the third transistor M3 and the first end of the fourth transistor M4 are both used to access the first voltage VOUT2.

[0082] Among them, the first end of the first transistor M1 is the first end of the latch circuit 122, the second end of the first transistor M1 is the second end A of the latch circuit 122, the second end of the second transistor M2 is the third end of the latch circuit 122, and the control end of the first transistor M1 is the fourth end C of the latch circuit 122.

[0083] Under the action of the output end of the input circuit 110 that pulls up the potential, the potential of the second end of the first transistor M1 is pulled up, so that the second transistor M2 is turned on. In this way, under the action of the turned-on second transistor M2, the potential of the control end B of the third transistor M3 is pulled up. When the potential of the control end B of the third transistor M3 is higher than the threshold voltage Vth of the third transistor M3, the third transistor M3 is turned on. In this way, the second transistor M2 and the third transistor M3 are both turned on, so that the first voltage VOUT2 pulls current from the control end GATE2 of the high-side power tube MD2.

[0084] At the same time, when the second transistor M2 and the third transistor M3 are both turned on, the fourth transistor M4 is turned on, so that the potential of the control terminal of the first transistor M1 is pulled down, so that positive feedback is formed. As a result, the potential of the second terminal of the first transistor M1 rises rapidly, so that the potential of the second terminal A of the latch circuit 122 rises rapidly.

[0085] After the control terminal GATE2 of the high-side power tube MD2 is completely discharged, no current flows through the second transistor M2 and the third transistor M3. In this way, the latch circuit 122 can trigger the de-latch to release the positive feedback of the positive feedback circuit 120. Thus, the current comparison circuit 100 can perform overcurrent detection again.

[0086] In summary, under the action of the output end of the input circuit that pulls up the potential, the potential of the second end of the first transistor is pulled up, so that the second transistor is turned on. In this way, under the action of the turned-on second transistor, the potential of the control end of the third transistor is pulled up, and when the potential of the control end of the third transistor is higher than the threshold voltage of the third transistor, the third transistor is turned on, so that both the second transistor and the third transistor are turned on, so that the first voltage pulls current from the control end of the high-side power tube. At the same time, when the second transistor and the third transistor are both turned on, the fourth transistor is turned on, so that the potential of the control end of the first transistor is pulled down, so that positive feedback is formed. As a result, the potential of the second end of the first transistor rises rapidly, so that the potential of the second end of the latch circuit rises rapidly.

[0087] Based on the description of the above embodiment, a possible implementation of the clamping circuit 121 is exemplified. Figure 3 As shown, the clamping circuit 121 may include: a first P-type MOS transistor Mp1, a second P-type MOS transistor Mp2, a first N-type MOS transistor Mn1, and a second N-type MOS transistor Mn2.

[0088] The first end of the first P-type MOS transistor Mp1 is used to access the working current, the second end of the first P-type MOS transistor Mp1 and the control end of the first P-type MOS transistor Mp1 are both electrically connected to the first end of the second P-type MOS transistor Mp2, the second end of the second P-type MOS transistor Mp2 and the control end of the second P-type MOS transistor Mp2 are both electrically connected to the second end of the first N-type MOS transistor Mn1, the second end of the first N-type MOS transistor Mn1 is also electrically connected to the control end of the first N-type MOS transistor Mn1, the first end of the first N-type MOS transistor Mn1 is electrically connected to the second end of the second N-type MOS transistor Mn2 and the control end of the second N-type MOS transistor Mn2, respectively, and the first end of the second N-type MOS transistor Mn2 is used to access the first voltage VOUT2.

[0089] Under the action of the working current, the first P-type MOS transistor Mp1, the second P-type MOS transistor Mp2, the first N-type MOS transistor Mn1, and the second N-type MOS transistor Mn2 are all turned on. In this way, after the latch circuit 122 can form positive feedback, the potential of the second terminal A of the latch circuit 122 can be clamped to the clamping voltage through the first P-type MOS transistor Mp1, the second P-type MOS transistor Mp2, the first N-type MOS transistor Mn1, and the second N-type MOS transistor Mn2. Thus, the potential of the second terminal A of the latch circuit 122 can be prevented from rising to the second voltage VCP2.

[0090] The clamping voltage refers to the sum of the threshold voltage of the first P-type MOS transistor Mp1, the threshold voltage of the second P-type MOS transistor Mp2, the threshold voltage of the first N-type MOS transistor Mn1, and the threshold voltage of the second N-type MOS transistor Mn2.

[0091] In summary, under the action of the working current, the first P-type MOS transistor Mp1, the second P-type MOS transistor Mp2, the first N-type MOS transistor Mn1, and the second N-type MOS transistor Mn2 are all turned on. In this way, the potential of the second end of the latch circuit can be clamped by the first P-type MOS transistor, the second P-type MOS transistor, the first N-type MOS transistor, and the second N-type MOS transistor. Thus, the clamping circuit can clamp the potential of the second end of the latch circuit, and can prevent the potential of the second end of the latch circuit from rising to the second voltage.

[0092] Based on the description of the above embodiment, a possible implementation of the input circuit 110 is exemplified. Figure 3 As shown, the input circuit 110 may include: a fifth transistor M5, a sixth transistor M6, a first resistor R1 and a second resistor R2.

[0093] The first end of the first resistor R1 and the first end of the second resistor R2 are both used to access the first voltage VOUT2, the second end of the first resistor R1 and the first end of the fifth transistor M5 are both used to access the mirror current ICL2, the second end of the fifth transistor M5 is electrically connected to the first end of the positive feedback circuit 120, the control end of the fifth transistor M5 is electrically connected to the control end of the sixth transistor M6, the second end of the second resistor R2 and the first end of the sixth transistor M6 are both used to access the reference current Iref2, and the second end of the sixth transistor M6 is used to access the working current.

[0094] The fifth transistor M5 and the first resistor R1 may constitute a first input terminal of the input circuit 110 , and the sixth transistor M6 and the second resistor R2 may constitute a second input terminal of the input circuit 110 .

[0095] When the mirror current ICL2 is greater than the reference current Iref2, that is, when the load current ILoad2 is too large, the potential of the first end of the fifth transistor M5 increases, so that the potential of the second end of the fifth transistor M5 increases. In this way, under the action of the second end of the fifth transistor M5 with the increased potential, the potential of the second end A of the latch circuit 122 increases. Therefore, under the action of the output end of the input circuit 110 with the potential pulled up, the latch circuit 122 can pull up the potential of the second end A of the latch circuit 122.

[0096] In summary, when the mirror current is greater than the reference current, the potential of the second end of the fifth transistor is increased by increasing the potential of the first end of the fifth transistor. In this way, under the action of the second end of the fifth transistor with increased potential, the potential of the second end of the latch circuit is increased. Thus, under the action of the output end of the input circuit that pulls up the potential, the latch circuit can pull up the potential of the second end of the latch circuit.

[0097] Based on the description of the above embodiment, another possible implementation of the current comparison circuit 100 is exemplified. Figure 3 As shown, the current comparison circuit 100 may further include: a seventh transistor M7 and a third resistor R3.

[0098] The second end of the seventh transistor M7 is used to access the working current, the control end of the seventh transistor M7 is electrically connected to the fourth end B of the latch circuit 122, the first end of the seventh transistor M7 is electrically connected to the first end of the third resistor R3, and the second end of the third resistor R3 is used to access the first voltage VOUT2.

[0099] The bias voltage can be provided to the first transistor M1 through the seventh transistor M7 and the third resistor R3 to change the working state of the first transistor M1. Thus, the latch circuit 122 can work.

[0100] The working state of the first transistor M1 may include: a cut-off state of the first transistor M1 , a saturation state of the first transistor M1 , and an amplification state of the first transistor M1 .

[0101] In summary, the bias voltage can be provided to the first transistor through the seventh transistor and the third resistor to change the working state of the first transistor. Thus, the latch circuit can work.

[0102] Based on the description of the above embodiment, another possible implementation of the current comparison circuit 100 is exemplified. Figure 3 As shown, the current comparison circuit 100 may further include: a working current output circuit 130 .

[0103] The power supply terminal of the working current output circuit 130 is used to access the second voltage VCP2 , and the output terminal of the working current output circuit 130 is electrically connected to the first terminal of the input circuit 110 .

[0104] Based on the description of the above embodiment, a possible implementation of the working current output circuit 130 is exemplified. Figure 3 As shown, the working current output circuit 130 may include: a first current mirror tube Mc1, a second current mirror tube Mc2, a third current mirror tube Mc3, a fourth current mirror tube Mc4, a fifth current mirror tube Mc5, a sixth current mirror tube Mc6, a seventh current mirror tube Mc7, an eighth current mirror tube Mc8 and a current source 131.

[0105] The first end of the first current mirror tube Mc1, the first end of the third current mirror tube Mc3, the first end of the fifth current mirror tube Mc5 and the first end of the seventh current mirror tube Mc7 are all used to access the second voltage VCP2, the control end of the first current mirror tube Mc1 is electrically connected to the second end of the first current mirror tube Mc1, the first end of the second current mirror tube Mc2, the control end of the third current mirror tube Mc3, the control end of the fifth current mirror tube Mc5 and the control end of the seventh current mirror tube Mc7, and the second end of the second current mirror tube Mc2 is electrically connected to the first end of the current source 131, the control end of the second current mirror tube Mc2, the control end of the fourth current mirror tube Mc4, the control end of the sixth current mirror tube Mc7 and the control end of the seventh current mirror tube Mc7. The control end of the current mirror tube Mc6 is electrically connected to the control end of the eighth current mirror tube Mc8, the second end of the third current mirror tube Mc3 is electrically connected to the first end of the fourth current mirror tube Mc4, the second end of the fifth current mirror tube Mc5 is electrically connected to the first end of the sixth current mirror tube Mc6, the second end of the seventh current mirror tube Mc7 is electrically connected to the first end of the eighth current mirror tube Mc8, the second end of the fourth current mirror tube Mc4 is electrically connected to the first end of the input circuit 110, the second end of the eighth current mirror tube Mc8 is electrically connected to the second end of the positive feedback circuit 120, the second end of the sixth current mirror tube Mc6 is used to output the working current, and the second end of the current source 131 is grounded.

[0106] The second end of the second current mirror tube Mc2 , the second end of the fourth current mirror tube Mc4 , the second end of the sixth current mirror tube Mc6 and the second end of the eighth current mirror tube Mc8 are all output ends of the working current output circuit 130 .

[0107] The second end of the sixth current mirror tube Mc6 is electrically connected to the second end of the seventh transistor M7.

[0108] The current source 131 can output a reference current IB, so that the second current mirror tube Mc2 can obtain the reference current IB.

[0109] Since the first current mirror tube Mc1, the second current mirror tube Mc2, the third current mirror tube Mc3, the fourth current mirror tube Mc4, the fifth current mirror tube Mc5, the sixth current mirror tube Mc6, the seventh current mirror tube Mc7 and the eighth current mirror tube Mc8 can form a current mirror. Therefore, after the second current mirror tube Mc2 obtains the reference current IB, the second end of the fourth current mirror tube Mc4 can output the working current through the first current mirror tube Mc1, the second current mirror tube Mc2, the third current mirror tube Mc3 and the fourth current mirror tube Mc4. Through the third current mirror tube Mc3, the fourth current mirror tube Mc4, the fifth current mirror tube Mc5 and the sixth current mirror tube Mc6, the second end of the sixth current mirror tube Mc6 can output the working current. Through the fifth current mirror tube Mc5, the sixth current mirror tube Mc6, the seventh current mirror tube Mc7 and the eighth current mirror tube Mc8, the second end of the eighth current mirror tube Mc8 can output the working current. Thus, the operating current output circuit 130 can output the operating current, so that the current comparison circuit 100 can operate.

[0110] In summary, after the second current mirror tube obtains the reference current, the second end of the fourth current mirror tube can output the working current through the first current mirror tube, the second current mirror tube, the third current mirror tube and the fourth current mirror tube. The second end of the sixth current mirror tube can output the working current through the third current mirror tube, the fourth current mirror tube, the fifth current mirror tube and the sixth current mirror tube. The second end of the eighth current mirror tube can output the working current through the fifth current mirror tube, the sixth current mirror tube, the seventh current mirror tube and the eighth current mirror tube. In this way, the working current output circuit can output the working current, so that the input circuit and the positive feedback circuit can obtain the working current. Thus, the current comparison circuit can operate.

[0111] It should be noted that: Figure 3 The transistor in the embodiment may be a metal oxide semiconductor field effect transistor device. At the same time, the transistor may also be an insulated gate bipolar transistor device, an integrated gate rectifier thyristor device, a gate turn-off thyristor device, a silicon controlled rectifier device, a junction gate field effect transistor device, a MOS controlled thyristor device, a gallium nitride-based power device, a silicon nitride-based power device, etc. The embodiments of the present application do not specifically limit this.

[0112] 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 current comparison circuit, characterized in that: The current comparison circuit comprises: a positive feedback circuit and an input circuit; The first input end of the input circuit is used to access the mirror current, and the mirror current is used to characterize the magnitude of the current when the high-side power tube is turned on. The second input end of the input circuit is used to access the reference current. The output end of the input circuit is electrically connected to the first end of the positive feedback circuit. The first end of the input circuit and the second end of the positive feedback circuit are both used to access the working current, and the working current is used to operate the current comparison circuit. The third end of the positive feedback circuit is electrically connected to the control end of the high-side power tube. The input circuit is used to pull up the potential of the output end of the input circuit when the mirror current is greater than the reference current, so as to pull up the potential of the second end of the positive feedback circuit; The positive feedback circuit is used to form positive feedback under the action of the second end of the positive feedback circuit that pulls up the potential, so as to quickly pull down the potential of the control end of the high-side power tube to the potential of the first voltage, so that the high-side power tube is turned off.

2. The circuit according to claim 1, characterized in that The positive feedback circuit is also used to release the positive feedback after the control end of the high-side power tube is completely discharged, so that the current comparison circuit can perform overcurrent detection again.

3. The circuit according to claim 2, characterized in that The positive feedback circuit comprises: a clamp circuit and a latch circuit; The first end of the latch circuit is electrically connected to the output end of the input circuit, the second end of the latch circuit and the first end of the clamp circuit are both used to access the working current, the third end of the latch circuit is electrically connected to the control end of the high-side power tube, and the fourth end of the latch circuit is used to access the bias voltage, and the bias voltage is used to determine the working state of the transistor in the latch circuit; The latch circuit is used to pull up the potential of the second end of the latch circuit under the action of the output end of the input circuit that pulls up the potential, so as to pull down the potential of the fourth end of the latch circuit, so that the positive feedback is formed; The clamping circuit is used to clamp the potential of the second end of the latch circuit.

4. The circuit according to claim 3, characterized in that The latch circuit comprises: a first transistor, a second transistor, a third transistor and a fourth transistor; The first end of the first transistor is electrically connected to the output end of the input circuit, the control end of the first transistor is used to access the bias voltage, the second end of the first transistor and the control end of the second transistor are both used to access the working current, the second end of the second transistor is electrically connected to the control end of the high-side power tube, the first end of the second transistor is respectively electrically connected to the second end of the third transistor, the control end of the third transistor and the control end of the fourth transistor, the second end of the fourth transistor is electrically connected to the control end of the first transistor, and the first end of the third transistor and the first end of the fourth transistor are both used to access the first voltage.

5. The circuit according to claim 3, characterized in that The clamping circuit comprises: a first P-type MOS transistor, a second P-type MOS transistor, a first N-type MOS transistor and a second N-type MOS transistor; The first end of the first P-type MOS tube is used to access the working current, the second end of the first P-type MOS tube and the control end of the first P-type MOS tube are both electrically connected to the first end of the second P-type MOS tube, the second end of the second P-type MOS tube and the control end of the first P-type MOS tube are both electrically connected to the second end of the first N-type MOS tube, the second end of the first N-type MOS tube is also electrically connected to the control end of the first N-type MOS tube, the first end of the first N-type MOS tube is respectively electrically connected to the second end of the second N-type MOS tube and the control end of the second N-type MOS tube, and the first end of the second N-type MOS tube is used to access the first voltage.

6. The circuit according to claim 2, characterized in that The input circuit includes: a fifth transistor, a sixth transistor, a first resistor and a second resistor; The first end of the first resistor and the first end of the second resistor are both used to access the first voltage, the second end of the first resistor and the first end of the fifth transistor are both used to access the mirror current, the second end of the fifth transistor is electrically connected to the first end of the positive feedback circuit, the control end of the fifth transistor is electrically connected to the control end of the sixth transistor, the second end of the second resistor and the first end of the sixth transistor are both used to access the reference current, and the second end of the sixth transistor is used to access the working current.

7. The circuit according to claim 3, characterized in that The current comparison circuit further includes: a seventh transistor and a third resistor; The second end of the seventh transistor is used to access the working current, the control end of the seventh transistor is electrically connected to the fourth end of the latch circuit, the first end of the seventh transistor is electrically connected to the first end of the third resistor, and the second end of the third resistor is used to access the first voltage.

8. The circuit according to any one of claims 1 to 7, characterized in that: The current comparison circuit also includes: a working current output circuit; The power supply end of the working current output circuit is used to access the second voltage, and the output end of the working current output circuit is electrically connected to the first end of the input circuit; The working current output circuit is used to output the working current.

9. The circuit according to claim 8, characterized in that The working current output circuit comprises: a first current mirror tube, a second current mirror tube, a third current mirror tube, a fourth current mirror tube, a fifth current mirror tube, a sixth current mirror tube, a seventh current mirror tube, an eighth current mirror tube and a current source; The first end of the first current mirror tube, the first end of the third current mirror tube, the first end of the fifth current mirror tube and the first end of the seventh current mirror tube are all used to access the second voltage, the control end of the first current mirror tube is electrically connected to the second end of the first current mirror tube, the first end of the second current mirror tube, the control end of the third current mirror tube, the control end of the fifth current mirror tube and the control end of the seventh current mirror tube respectively, the second end of the second current mirror tube is electrically connected to the first end of the current source, the control end of the second current mirror tube, the control end of the fourth current mirror tube, the control end of the sixth current mirror tube and the control end of the eighth current mirror tube respectively, the second end of the third current mirror tube is electrically connected to the first end of the fourth current mirror tube, the second end of the fifth current mirror tube is electrically connected to the first end of the sixth current mirror tube, the second end of the seventh current mirror tube is electrically connected to the first end of the eighth current mirror tube, the second end of the fourth current mirror tube is electrically connected to the first end of the input circuit, the second end of the eighth current mirror tube is electrically connected to the second end of the positive feedback circuit, the second end of the sixth current mirror tube is used to output the working current, and the second end of the current source is grounded; The current source is used to output a reference current so that the working current output circuit can output the working current.

10. A driver chip, characterized in that: include: A driver, a high-side power tube, a mirror circuit and a current comparison circuit as claimed in any one of claims 1 to 9; The input end of the driver is used to access a driving signal, and the driving signal is used to drive the high-side power tube to be turned on or off. The output end of the driver is electrically connected to the control end of the high-side power tube. The first end of the high-side power tube and the first end of the mirror circuit are both used to access a power supply voltage. The second end of the mirror circuit is electrically connected to the first input end of the current comparison circuit. The second input end of the current comparison circuit is used to access a reference current. The output end of the current comparison circuit and the control end of the mirror circuit are both electrically connected between the output end of the driver and the control end of the high-side power tube. The power supply end of the current comparison circuit is used to access a second voltage. The ground end of the current comparison circuit is used to access a first voltage. The second end of the high-side power tube is grounded. The current comparison circuit is located in a voltage domain between the second voltage and the first voltage. The driver is used to drive the high-side power tube to conduct according to the driving signal; The mirror circuit is used to mirror the current of the high-side power tube when it is turned on to obtain a mirror current; The current comparison circuit is used to obtain the mirror current from the mirror circuit, and when the mirror current is greater than the reference current, quickly pull down the potential of the control end of the high-side power tube to the potential of the first voltage to turn off the high-side power tube.

11. An electronic device, characterized in that: include: The driver chip as claimed in claim 10.

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