Constant current control circuit and driving chip, electronic device

Abstract

The present disclosure relates to a constant current control circuit, a driving chip and an electronic device. The circuit comprises a voltage detection unit, an amplification unit and a constant current control unit. The voltage detection unit is connected to the gate of a driven transistor, the negative input end of the amplification unit and the current output end of the constant current control unit. The positive input end of the amplification unit is used to receive an amplified reference voltage. The voltage detection unit is used to obtain a detection voltage according to the driving current output to the gate of the driven transistor. The amplification unit is used to amplify the difference between the amplified reference voltage and the detection voltage and output an amplified signal. The constant current control unit is connected to the amplification unit and is used to adjust the driving current according to the amplified signal to achieve constant current driving of the driven transistor. The embodiment of the present disclosure can ensure that the voltage change rate remains relatively constant when the transistor is turned on under different loads, thereby facilitating EMI control.

Description

Technical Field

[0001] This disclosure relates to the field of integrated circuit technology, and in particular to a constant current control circuit and driver chip, and electronic equipment. Background Technology

[0002] Currently, all semiconductor power devices on the market require a drive circuit. The switching speed of semiconductor power devices is determined by the drive current of the drive circuit. However, most of the current drives are constant voltage drives, which results in different dV / dT (voltage change rate) under different load conditions. The difference in dV / dT makes EMI control difficult. Summary of the Invention

[0003] According to one aspect of this disclosure, a constant current control circuit is provided, the circuit comprising: a voltage detection unit, an amplification unit, and a constant current control unit, wherein,

[0004] The first terminal of the voltage detection unit is connected to the gate of the driven transistor, the second terminal of the voltage detection unit is connected to the negative input terminal of the amplification unit and the current output terminal of the constant current control unit, the positive input terminal of the amplification unit is used to receive the amplified reference voltage, the voltage detection unit is used to obtain the detection voltage according to the driving current output to the gate of the driven transistor, and the amplification unit is used to amplify the difference between the amplified reference voltage and the detection voltage and output an amplified signal.

[0005] The constant current control unit is connected to the amplification unit and is used to adjust the drive current according to the amplified signal to achieve constant current drive of the driven transistor.

[0006] In one possible implementation, the voltage detection unit includes a first diode, a first resistor, and a second resistor, wherein,

[0007] The anode of the first diode is connected to the first terminal of the second resistor, the negative input terminal of the amplification unit, and the current output terminal of the constant current control unit.

[0008] The negative terminal of the first diode is connected to the first end of the first resistor, and the second ends of the first resistor and the second resistor are both connected to the gate of the driven transistor.

[0009] In one possible implementation, the constant current control unit includes a constant current control circuit, a current mirror, and a third transistor, wherein,

[0010] The constant current control circuit is connected to the output terminal of the amplification unit, the first terminal of the current mirror, and the gate of the third transistor. The constant current control circuit generates a control current based on the amplified signal and inputs it to the first terminal of the current mirror. The second terminal of the current mirror outputs a mirror current of the control current.

[0011] The second terminal of the current mirror is connected to the drain of the third transistor and the second terminal of the voltage detection unit, and the source of the third transistor is grounded.

[0012] The constant current control circuit is also used to control the third transistor to turn on or off according to the control signal.

[0013] In one possible implementation, the constant current control circuit includes a NOR gate, a buffer, a NOT gate, an OR gate, a second diode, and a third resistor; the current mirror includes a fourth transistor and a fifth transistor, wherein...

[0014] The first input terminal of the NOR gate and the input terminal of the NOT gate are used to receive the control signal.

[0015] The second input terminal of the NOR gate is connected to the first input terminal of the OR gate.

[0016] The output of the NOR gate is connected to the input of the buffer, and the output of the buffer is connected to the gate of the third transistor.

[0017] The output of the NOT gate is connected to the second input of the OR gate.

[0018] The output of the OR gate is connected to the positive terminal of the second diode, and the first end of the third resistor is connected to the output of the amplification unit.

[0019] The collector of the fourth transistor is connected to the base of the fourth transistor, the base of the fifth transistor, the output terminal of the second diode, and the second terminal of the third resistor, for receiving the control current.

[0020] The emitter of the fourth transistor and the emitter of the fifth transistor are used to receive the power supply voltage.

[0021] The collector of the fifth transistor is connected to the drain of the third transistor, the negative input terminal of the amplification unit, the positive terminal of the first diode, and the first terminal of the second resistor.

[0022] In one possible implementation, the circuit further includes:

[0023] A Miller clamping unit is used to clamp the driven transistor. The Miller clamping unit includes a second transistor and a comparator. The source of the second transistor is connected to the positive input of the comparator and the gate of the driven transistor. The drain of the second transistor is grounded. The gate of the second transistor is used to receive a Miller control voltage.

[0024] The negative input terminal of the comparator is used to receive the comparison threshold voltage, and the output terminal of the comparator is used to output the comparison result.

[0025] In one possible implementation, the constant current control circuit further includes a control component connected to the constant current control unit for controlling the constant current control unit to drive the driven transistor with a constant current.

[0026] According to one aspect of this disclosure, a driver chip is provided, the chip including the aforementioned constant current control circuit.

[0027] According to one aspect of this disclosure, an electronic device is provided, the electronic device including the aforementioned driver chip.

[0028] In this embodiment, a voltage detection unit obtains a detection voltage based on the drive current output to the gate of the driven transistor. The amplification unit amplifies the difference between the amplified reference voltage and the detection voltage, outputting an amplified signal. A constant current control unit adjusts the drive current based on the amplified signal to achieve constant current drive of the driven transistor. This ensures that the transistor maintains a relatively constant voltage change rate when it is turned on under different loads, facilitating EMI control.

[0029] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Other features and aspects of this disclosure will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0030] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the specification, serve to illustrate the technical solutions of this disclosure.

[0031] Figure 1 A schematic diagram of a constant current control circuit according to an embodiment of the present disclosure is shown.

[0032] Figure 2 A schematic diagram of a constant current control circuit according to an embodiment of the present disclosure is shown.

[0033] Figure 3 A schematic diagram of a constant current control circuit according to an embodiment of the present disclosure is shown. Detailed Implementation

[0034] Various exemplary embodiments, features, and aspects of this disclosure will now be described in detail with reference to the accompanying drawings. The same reference numerals in the drawings denote elements that have the same or similar functions. Although various aspects of the embodiments are shown in the drawings, they are not necessarily drawn to scale unless specifically indicated otherwise.

[0035] In the description of this disclosure, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this disclosure and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this disclosure.

[0036] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this disclosure, "a plurality of" means two or more, unless otherwise expressly specified.

[0037] In this disclosure, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances.

[0038] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments.

[0039] In this document, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A alone, A and B simultaneously, and B alone. Furthermore, the term "at least one" in this document means any combination of at least two of any one or more elements. For example, including at least one of A, B, and C can mean including any one or more elements selected from the set consisting of A, B, and C.

[0040] Furthermore, to better illustrate this disclosure, numerous specific details are set forth in the following detailed description. Those skilled in the art will understand that this disclosure can be practiced without certain specific details. In some instances, methods, means, components, and circuits well known to those skilled in the art have not been described in detail in order to highlight the main points of this disclosure.

[0041] Please see Figure 1 , Figure 1 A schematic diagram of a constant current control circuit according to an embodiment of the present disclosure is shown.

[0042] like Figure 1 As shown, the circuit includes: a voltage detection unit 10, an amplification unit 20, and a constant current control unit 30, wherein,

[0043] The first terminal of the voltage detection unit 10 is connected to the gate of the driven transistor Q1, and the second terminal of the voltage detection unit 10 is connected to the negative input terminal of the amplification unit 20 and the current output terminal of the constant current control unit 30. The positive input terminal of the amplification unit 20 is used to receive the amplified reference voltage VR2. The voltage detection unit 10 is used to obtain the detection voltage based on the driving current Iout output to the gate of the driven transistor Q1. The amplification unit 20 is used to amplify the difference between the amplified reference voltage VR2 and the detection voltage and output an amplified signal.

[0044] The constant current control unit 30 is connected to the amplification unit 20 and is used to adjust the drive current Iout according to the amplified signal to achieve constant current drive of the driven transistor Q1.

[0045] In this embodiment, the voltage detection unit 10 obtains the detection voltage based on the drive current Iout output to the gate of the driven transistor Q1. The amplification unit 20 amplifies the difference between the amplified reference voltage VR2 and the detection voltage, outputting an amplified signal. The constant current control unit 30 adjusts the drive current Iout based on the amplified signal to achieve constant current drive of the driven transistor Q1. This ensures that the voltage change rate remains relatively constant when the transistor is turned on under different loads, facilitating EMI control.

[0046] Furthermore, the constant current control circuit of this disclosure has the advantages of simple structure and low cost compared with the complex circuits in related technologies, making it easy to promote and utilize.

[0047] For example, the amplification unit 20 may include an error amplifier. The amplification unit 20 amplifies the difference between the amplified reference voltage VR2 and the detected voltage. After outputting the amplified signal, the constant current control unit 30 can generate a control current according to the amplified signal, thereby adjusting the drive current.

[0048] The present disclosure does not limit the specific implementation of the voltage detection unit 10, the amplification unit 20, and the constant current control unit 30. Those skilled in the art can choose appropriate technical means to implement them according to actual conditions and needs. The following provides an exemplary description of the possible implementations of the voltage detection unit 10, the amplification unit 20, and the constant current control unit 30.

[0049] Please see Figure 2 , Figure 2 A schematic diagram of a constant current control circuit according to an embodiment of the present disclosure is shown.

[0050] In one possible implementation, such as Figure 2 As shown, the voltage detection unit 10 may include a first diode D1, a first resistor R1, and a second resistor R2, wherein,

[0051] The anode of the first diode D1 is connected to the first terminal of the second resistor R2, the negative input terminal of the amplification unit 20, and the current output terminal of the constant current control unit 30.

[0052] The cathode of the first diode D1 is connected to the first end of the first resistor R1, and the second ends of the first resistor R1 and the second ends of the second resistor R2 are both connected to the gate of the driven transistor Q1.

[0053] This disclosure does not limit the device parameters or types of the first diode D1, the first resistor R1, and the second resistor R2. Those skilled in the art can select suitable devices for application in the constant current control circuit of this disclosure according to actual conditions and needs. This disclosure uses the first resistor R1 and the second resistor R2 on the drive circuit for current detection, which can improve detection efficiency and reduce detection cost. There is no need to set up other complex detection circuits or complex detection logic.

[0054] In one possible implementation, such as Figure 2 As shown, the constant current control unit 30 may include a constant current control circuit 310, a current mirror 320, and a third transistor Q3, wherein,

[0055] The constant current control circuit 310 is connected to the output terminal of the amplification unit 20, the first terminal of the current mirror 320, and the gate of the third transistor Q3. The constant current control circuit 310 is used to generate a control current according to the amplified signal and input it to the first terminal of the current mirror 320. The second terminal of the current mirror 320 is used to output a mirror current of the control current.

[0056] The second terminal of the current mirror 320 is connected to the drain of the third transistor Q3 and the second terminal of the voltage detection unit 10, and the source of the third transistor Q3 is grounded.

[0057] The constant current control circuit 310 is also used to control the third transistor Q3 to turn on or off according to the control signal.

[0058] In this embodiment, the constant current control circuit 310 generates a control current based on the amplified signal and inputs it to the first terminal of the current mirror 320. The current mirror 320 then outputs a mirror current of the control current to the driven transistor Q1, enabling adaptive adjustment of the drive current Iout to achieve constant current driving of the driven transistor Q1. Furthermore, through the control of the third transistor Q3, this embodiment can conveniently drive the operating state of the driving circuit. For example, when constant current driving of the driven transistor Q1 is required, the third transistor Q3 can be disconnected via a control signal, and the constant current control unit 30 outputs the drive current Iout to drive the driven transistor Q1. The voltage detection unit 10, amplification unit 20, and constant current control unit 30 work together to adaptively adjust the drive current Iout, achieving constant current driving of the driven transistor Q1. For example, when it is necessary to turn off the driven transistor Q1, the third transistor Q3 can be turned on via a control signal, thus pulling the driven transistor Q1 down through the second resistor R2.

[0059] The present disclosure does not limit the specific implementation of the constant current control circuit 310 and the current mirror 320. Those skilled in the art can choose appropriate technical means to implement them according to the actual situation and needs. The following is an exemplary description of the possible implementations of the constant current control circuit 310 and the current mirror 320.

[0060] Please see Figure 3 , Figure 3 A schematic diagram of a constant current control circuit according to an embodiment of the present disclosure is shown.

[0061] In one possible implementation, such as Figure 3 As shown, the constant current control circuit 310 may include a NOR gate 3110, a buffer 3113, a NOT gate 3111, an OR gate 3112, a second diode D2, and a third resistor R3. The current mirror 320 may include a fourth transistor Q4 and a fifth transistor Q5.

[0062] The first input terminal of the NOR gate 3110 and the input terminal of the NOT gate 3111 are used to receive the control signal.

[0063] The second input terminal of the NOR gate 3110 is connected to the first input terminal of the OR gate 3112.

[0064] The output of the NOR gate 3110 is connected to the input of the buffer 3113, and the output of the buffer 3113 is connected to the gate of the third transistor Q3.

[0065] The output of the NOT gate 3111 is connected to the second input of the OR gate 3112.

[0066] The output terminal of the OR gate 3112 is connected to the positive terminal of the second diode D2, and the first terminal of the third resistor R3 is connected to the output terminal of the amplifier unit 20.

[0067] The collector of the fourth transistor Q4 is connected to the base of the fourth transistor Q4, the base of the fifth transistor Q5, the output terminal of the second diode D2, and the second terminal of the third resistor R3, for receiving the control current.

[0068] The emitter of the fourth transistor Q4 and the emitter of the fifth transistor Q5 are used to receive the power supply voltage.

[0069] The collector of the fifth transistor Q5 is connected to the drain of the third transistor Q3, the negative input terminal of the amplification unit 20, the positive terminal of the first diode D1, and the first terminal of the second resistor R2.

[0070] For example, the second input terminal of the NOR gate 3110 and the first input terminal of the OR gate 3112 can be set to float.

[0071] For example, such as Figure 3 As shown, if the third transistor Q3 is a PMOS transistor, when the input signal Vg is high, the NOR gate 3110 outputs a high level, and correspondingly, the buffer 3113 also outputs a high level, turning off the third transistor Q3. The constant current circuit then generates a drive current Iout to drive the driven transistor Q1, as shown. Figure 3 As shown, the constant current control is implemented by generating a drive current Iout when the third transistor Q3 is turned off. This generates a detection voltage across the first resistor R1 and the second resistor R2 connected in parallel. When the detection voltage is lower than the amplified reference voltage VR2, the constant current control circuit 310 increases the output drive current Iout until the voltage difference between the MCLP node and the OUTH node (i.e., the two input terminals of the error amplifier Diff) reaches the amplified reference voltage VR2 and enters a balanced state. The output is the set current, thus realizing constant current drive.

[0072] For example, the following are specific applications of the drive current Iout and the turn-off resistor:

[0073] Assuming the power supply voltage VDD=20V and the amplified reference voltage VR2=2V, if the resistance Roff of the second resistor R2=2 ohms, then the maximum shutdown current=20V / 2Ohm=10A. If the drive current Iout is to be set to 5A, since the amplified reference voltage VR2 is also applied to the second resistor R2, the resulting current is 2V / 2Ohm=1A. Therefore, the current flowing through the first resistor R1 is 5A-1A=4A. If the voltage drop of the first diode D1 is 0.4V, the resistance Ron of the first resistor R1=(2V-0.4V) / 4A=0.4Ohm.

[0074] In one possible implementation, such as Figure 2 As shown, the circuit may further include:

[0075] Miller clamping unit 40 is used to Miller clamp the driven transistor Q1. The Miller clamping unit 40 includes a second transistor Q2 and a comparator COM. The source of the second transistor Q2 is connected to the positive input terminal of the comparator COM and the gate of the driven transistor Q1. The drain of the second transistor Q2 is grounded. The gate of the second transistor Q2 is used to receive the Miller control voltage Vm.

[0076] The negative input terminal of the comparator COM is used to receive the comparison threshold voltage VR1, and the output terminal of the comparator COM is used to output the comparison result Vco.

[0077] For example, such as Figure 2 As shown, in this embodiment of the present disclosure, the constant current control unit 30 and the Miller clamping unit 40 share a single pin (MCLP). By sharing the pin, this embodiment of the present disclosure can reuse the pins, thereby reducing the pin usage of the driver chip. Compared with related technologies that require additional detection and driving and use additional pins, this embodiment of the present disclosure can reduce costs and improve pin utilization efficiency.

[0078] In one possible implementation, the constant current control circuit may further include a control component 50 connected to the constant current control unit 30, for controlling the constant current control unit 30 to drive the driven transistor Q1 with a constant current.

[0079] This disclosure does not limit the specific implementation of the control component 50. Those skilled in the art can choose appropriate technical means to implement it according to actual conditions and needs. For example, the control component 50 may include a processing component. In one example, the processing component includes, but is not limited to, a separate processor, discrete components, or a combination of a processor and discrete components. The processor may include a controller in an electronic device that has the function of executing instructions. The processor can be implemented in any suitable manner, for example, by one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), controllers, microcontrollers, microprocessors, or other electronic components. Inside the processor, the executable instructions can be executed by hardware circuits such as logic gates, switches, application-specific integrated circuits (ASICs), programmable logic controllers, and embedded microcontrollers.

[0080] According to one aspect of this disclosure, a driver chip is provided, the chip including the aforementioned constant current control circuit.

[0081] According to one aspect of this disclosure, an electronic device is provided, the electronic device including the aforementioned driver chip.

[0082] In one possible implementation, the electronic device may include a high-power device, such as a device used in new energy vehicles.

Claims

1. A constant current control circuit, characterized in that, The circuit includes: a voltage detection unit, an amplification unit, and a constant current control unit, wherein... The first terminal of the voltage detection unit is connected to the gate of the driven transistor, the second terminal of the voltage detection unit is connected to the negative input terminal of the amplification unit and the current output terminal of the constant current control unit, the positive input terminal of the amplification unit is used to receive the amplified reference voltage, the voltage detection unit is used to obtain the detection voltage according to the driving current output to the gate of the driven transistor, and the amplification unit is used to amplify the difference between the amplified reference voltage and the detection voltage and output an amplified signal. The constant current control unit is connected to the amplification unit and is used to adjust the drive current according to the amplified signal to achieve constant current drive of the driven transistor. The constant current control unit includes a constant current control circuit, a current mirror, and a third transistor, wherein... The constant current control circuit is connected to the output terminal of the amplification unit, the first terminal of the current mirror, and the gate of the third transistor. The constant current control circuit generates a control current based on the amplified signal and inputs it to the first terminal of the current mirror. The second terminal of the current mirror outputs a mirror current of the control current. The second terminal of the current mirror is connected to the drain of the third transistor and the second terminal of the voltage detection unit, and the source of the third transistor is grounded. The constant current control circuit is also used to control the third transistor to turn on or off according to the control signal. The constant current control circuit includes a NOR gate, a buffer, a NOT gate, an OR gate, a second diode, and a third resistor; the current mirror includes a fourth transistor and a fifth transistor, wherein... The first input terminal of the NOR gate and the input terminal of the NOT gate are used to receive the control signal. The second input terminal of the NOR gate is connected to the first input terminal of the OR gate. The output of the NOR gate is connected to the input of the buffer, and the output of the buffer is connected to the gate of the third transistor. The output of the NOT gate is connected to the second input of the OR gate. The output of the OR gate is connected to the positive terminal of the second diode, and the first end of the third resistor is connected to the output of the amplification unit. The collector of the fourth transistor is connected to the base of the fourth transistor, the base of the fifth transistor, the output terminal of the second diode, and the second terminal of the third resistor, for receiving the control current. The emitter of the fourth transistor and the emitter of the fifth transistor are used to receive the power supply voltage. The collector of the fifth transistor is connected to the drain of the third transistor and the negative input terminal of the amplification unit.

2. The constant current control circuit according to claim 1, characterized in that, The voltage detection unit includes a first diode, a first resistor, and a second resistor, wherein, The anode of the first diode is connected to the first terminal of the second resistor, the negative input terminal of the amplification unit, and the current output terminal of the constant current control unit. The negative terminal of the first diode is connected to the first end of the first resistor, and the second ends of the first resistor and the second resistor are both connected to the gate of the driven transistor.

3. The constant current control circuit according to claim 1, characterized in that, The circuit also includes: A Miller clamping unit is used to clamp the driven transistor. The Miller clamping unit includes a second transistor and a comparator. The source of the second transistor is connected to the positive input of the comparator and the gate of the driven transistor. The drain of the second transistor is grounded. The gate of the second transistor is used to receive a Miller control voltage. The negative input terminal of the comparator is used to receive the comparison threshold voltage, and the output terminal of the comparator is used to output the comparison result.

4. The constant current control circuit according to any one of claims 1 to 3, characterized in that, The constant current control circuit also includes a control component connected to the constant current control unit, used to control the constant current control unit to drive the driven transistor with a constant current.

5. A driver chip, characterized in that, The chip includes a constant current control circuit as described in any one of claims 1 to 4.

6. An electronic device, characterized in that, The electronic device includes the driver chip as described in claim 5.

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