Output over-current self-locking isolation protection circuit of DCDC power supply module

Abstract

The invention discloses a DCDC power supply module output overcurrent self-locking isolation protection circuit, which comprises a current sampling circuit and a signal amplification circuit, and also comprises a signal comparison circuit, an isolation control circuit and a self-locking protection circuit, the input end of the current sampling circuit is connected with the output end of a DCDC power supply module, and the output end of the signal amplification circuit is connected with the isolation control circuit. The current sampling circuit, the signal amplification circuit, the signal comparison circuit, the isolation control circuit and the self-locking protection circuit are connected in sequence, and the output end of the self-locking protection circuit is connected to a control pin of the DCDC power supply module. According to the invention, the current sampling circuit, the signal amplification circuit, the signal comparison circuit, the isolation control circuit and the self-locking protection circuit are connected in sequence, so that when the output current of the DCDC power supply module is increased, the control pin of the power supply module can be controlled, and the output of the power supply module is cut off. The power supply module can be protected from being damaged, and the power supply module can work normally after being electrified again.

Description

Technical Field

[0001] The invention relates to the technical field of power electronics, and in particular to a DCDC power module output overcurrent self-locking isolation protection circuit. Background Art

[0002] With the continuous development of power electronics technology, airborne electrical equipment has higher and higher performance requirements for power modules. The power modules need to continuously provide power to airborne electrical equipment. During the operation of airborne electrical equipment, the required power supply current will suddenly increase, which may exceed the output current capacity of the power module, causing damage to the power module or reducing the service life of the power module. The existing overcurrent protection circuit cannot simultaneously realize isolation control and overcurrent self-locking protection functions. Summary of the invention

[0003] The object of the present invention is to provide a DCDC power module output overcurrent self-locking isolation protection circuit to solve the problem that the existing overcurrent protection circuit cannot simultaneously realize isolation control and overcurrent self-locking protection functions. In order to achieve the above purpose, the present invention adopts the following technical solutions: A DCDC power module output overcurrent self-locking isolation protection circuit, comprising a current sampling circuit and a signal amplifying circuit, and further comprising a signal comparison circuit, an isolation control circuit and a self-locking protection circuit, wherein the input end of the current sampling circuit is connected to the output end of the DCDC power module, the current sampling circuit, the signal amplifying circuit, the signal comparison circuit, the isolation control circuit and the self-locking protection circuit are connected in sequence, and the output end of the self-locking protection circuit is connected to the control pin of the DCDC power module; The current sampling circuit is used to collect signals of the output current of the DCDC power supply module; the signal amplification circuit is used to amplify the signal obtained by the current sampling circuit; the signal comparison circuit is used to compare the signal amplified by the signal amplification circuit with the reference signal, and transmit the signal obtained after comparison to the isolation control circuit; the isolation control circuit is used to generate a control signal according to the signal obtained after comparison sent by the signal comparison circuit, and transmit the control signal to the self-locking protection circuit; the self-locking protection circuit is used to control the self-locking protection circuit with the control signal of the isolation control circuit, and realize self-locking when an overcurrent signal comes.

[0004] Furthermore, the current sampling circuit includes a resistor R10, a resistor R11, a voltage regulator Z1 and a capacitor C3, wherein one end of the resistor R10 is connected to one end of the resistor R11, and the connection point is connected to the output end of the DCDC power supply module as the input end of the current sampling circuit; the other end of the resistor R10 is commonly connected to one end of the voltage regulator Z1 and one end of the capacitor C3, and the connection point is connected to the input end of the signal amplification circuit as the input end of the current sampling circuit; the other end of the resistor R11, the other end of the voltage regulator Z1 and the other end of the capacitor C3 are commonly grounded.

[0005] Furthermore, the signal amplification circuit includes an operational amplifier U3, a resistor R8 and a resistor R9, wherein pin 3 of the operational amplifier U3 is connected to the output end of the current sampling circuit as the input end of the signal amplification circuit; pin 4 of the operational amplifier U3 is connected to one end of the resistor R8 and one end of the resistor R9; pin 2 of the operational amplifier U3 is connected to the first input end of the signal comparison circuit as the first output end of the signal amplification circuit; the other end of the resistor R8 is connected to pin 1 of the operational amplifier U3, and the connection point is connected to the second input end of the signal comparison circuit as the second output end of the signal amplification circuit; pin 5 of the operational amplifier U3 is grounded.

[0006] Furthermore, the signal comparison circuit includes a resistor R5, a resistor R6, a resistor R7, a diode D2 and an operational amplifier U2, wherein one end of the resistor R6 is connected to pin 2 of the operational amplifier U2 and one end of the resistor R5, and the connection point is connected to the first output end of the signal amplification circuit as the first input end of the signal comparison circuit; the other end of the resistor R6 is connected to one end of the resistor R7 and pin 4 of the operational amplifier U2, and the other end of the resistor R7 is grounded; pin 3 of the operational amplifier U2 is connected to the second output end of the signal amplification circuit as the second input end of the signal comparison circuit; pin 5 of the operational amplifier U2 is grounded; pin 1 of the operational amplifier U2 is connected to one end of the resistor R5 and the anode of the diode D2, and the anode of the diode D2 is connected to the input end of the isolation control circuit as the output end of the signal comparison circuit.

[0007] Furthermore, the isolation control circuit includes a resistor R4 and an optocoupler U1, wherein one end of the resistor R4 is connected to the output end of the signal comparison circuit as the input end of the isolation control circuit; the other end of the resistor R4 is connected to pin 1 of the optocoupler U1; pin 2 of the optocoupler U1 is grounded; pin 3 of the optocoupler U1 is connected to the first input end of the self-locking protection circuit, and pin 4 of the optocoupler U1 is connected to the second input end of the self-locking protection circuit.

[0008] Furthermore, the self-locking protection circuit includes a resistor R1, a resistor R2, a resistor R3, a capacitor C1, a capacitor C2, a diode D1, a transistor Q1 and a MOS tube Q2, wherein the cathode of the diode D1 is commonly connected to one end of the capacitor C1, one end of the resistor R2, the base of the transistor Q1, and the drain of the MOS tube Q2, and the connection point is connected to the isolation control circuit as the first input end of the self-locking protection circuit; the anode of the diode D1 is connected to the control pin of the DCDC power supply module as the output end of the self-locking protection circuit; the other end of the capacitor C1 is commonly connected to one end of the resistor R1, the other end of the resistor R2, and the emitter of the transistor Q1; the other end of the resistor R1 is connected to the positive input end; the collector of the transistor Q1 is commonly connected to one end of the capacitor C2, one end of the resistor R3, and the gate of the MOS tube Q2; the other end of the capacitor C2 is commonly connected to the other end of the resistor R3 and the source of the MOS tube Q2, and the connection point is commonly connected to the ground end of the isolation control circuit as the second input end of the self-locking protection circuit.

[0009] Compared with the prior art, the technical effects of the present invention are as follows: (1) The present invention sequentially connects a current sampling circuit, a signal amplification circuit, a signal comparison circuit, an isolation control circuit, and a self-locking protection circuit, and reasonably sets the parameters of the circuit components, so that when the output current of the DC-DC power module increases, the control pin of the power module can be controlled to shut down the output of the power module. The power module can be protected from damage, and after normal power-on, the power module can work normally.

[0010] (2) The circuit structure of the present invention is easy to implement and has low cost. The module output current can flexibly and conveniently set the overcurrent point according to the sampling circuit. It is suitable for most DC-DC power modules and can effectively prevent the DC-DC power conversion module from being damaged or malfunctioning when the output current increases, thereby improving the safety and reliability of the power module. It is an overcurrent self-locking isolation protection circuit with excellent performance, simplicity and practicality.

[0011] (3) Each circuit of the present invention is composed of discrete components, and the overcurrent point can be set as needed. It is flexible and convenient to use and has low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 The present invention is a structural block diagram of a DCDC power module output overcurrent self-locking isolation protection circuit.

[0013] Figure 2 4 is a circuit diagram of an embodiment of the present invention. DETAILED DESCRIPTION

[0014] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0015] like Figure 1 As shown, the DCDC power module output overcurrent self-locking isolation protection circuit provided by the present invention includes a current sampling circuit 1, a signal amplifying circuit 2, a signal comparing circuit 3, an isolation control circuit 4 and a self-locking protection circuit 5, wherein the input end of the current sampling circuit 1 is connected to the output end of the DCDC power module, the current sampling circuit 1, the signal amplifying circuit 2, the signal comparing circuit 3, the isolation control circuit 4 and the self-locking protection circuit 5 are connected in sequence, and the output end of the self-locking protection circuit 5 is connected to the control pin of the DCDC power module.

[0016] In the above technical scheme, the current sampling circuit 1 is used to collect the signal of the output current of the DCDC power module; the signal amplifying circuit 2 is used to amplify the signal obtained by the current sampling circuit 1; the signal comparison circuit 3 is used to compare the signal amplified by the signal amplifying circuit 2 with the reference signal, and transmit the signal obtained after comparison to the isolation control circuit 4; the isolation control circuit 4 is used to generate a control signal according to the signal obtained after comparison sent by the signal comparison circuit 3, and transmit the control signal to the self-locking protection circuit 5; the self-locking protection circuit 5 is used to control the self-locking protection circuit 5 with the control signal of the isolation control circuit 4, and realize self-locking when an overcurrent signal comes.

[0017] Embodiment 1: This embodiment is a preferred embodiment of the present invention. Figure 2 In the DCDC power module output overcurrent self-locking isolation protection circuit provided in this embodiment, each circuit is configured as follows: The current sampling circuit 1 includes a resistor R10, a resistor R11, a voltage regulator Z1 and a capacitor C3, wherein one end of the resistor R10 is connected to one end of the resistor R11, and the connection point is connected to the output end (end A, current signal) of the DCDC power module as the input end of the current sampling circuit 1; the other end of the resistor R10 is commonly connected to one end of the voltage regulator Z1 and one end of the capacitor C3, and the connection point is connected to the input end of the signal amplification circuit 2 as the input end of the current sampling circuit 1; the other end of the resistor R11, the other end of the voltage regulator Z1 and the other end of the capacitor C3 are commonly grounded.

[0018] The signal amplifying circuit 2 includes an operational amplifier U3, a resistor R8 and a resistor R9, wherein the pin 3 of the operational amplifier U3 is connected to the output end of the current sampling circuit 1 as the input end of the signal amplifying circuit 2; the pin 4 of the operational amplifier U3 is connected to one end of the resistor R8 and one end of the resistor R9; the pin 2 of the operational amplifier U3 is connected to the first input end of the signal comparison circuit 3 as the first output end VCC of the signal amplifying circuit 2; the other end of the resistor R8 is connected to the pin 1 of the operational amplifier U3, and the connection point is connected to the second input end of the signal comparison circuit 3 as the second output end of the signal amplifying circuit 2; the pin 5 of the operational amplifier U3 is grounded.

[0019] The signal comparison circuit 3 includes a resistor R5, a resistor R6, a resistor R7, a diode D2 and an operational amplifier U2, wherein one end of the resistor R6 is connected to pin 2 of the operational amplifier U2 and one end of the resistor R5, and the connection point is connected to the first output end VCC of the signal amplification circuit 2 as the first input end of the signal comparison circuit 3; the other end of the resistor R6 is connected to one end of the resistor R7 and pin 4 of the operational amplifier U2, and the other end of the resistor R7 is grounded; pin 3 of the operational amplifier U2 is connected to the second output end of the signal amplification circuit 2 as the second input end of the signal comparison circuit 3; pin 5 of the operational amplifier U2 is grounded; pin 1 of the operational amplifier U2 is connected to one end of the resistor R5 and the anode of the diode D2, and the anode of the diode D2 is connected to the input end of the isolation control circuit 4 as the output end of the signal comparison circuit 3.

[0020] The isolation control circuit 4 includes a resistor R4 and an optocoupler U1, wherein one end of the resistor R4 is connected to the output end of the signal comparison circuit 3 as the input end of the isolation control circuit 4; the other end of the resistor R4 is connected to pin 1 of the optocoupler U1; pin 2 of the optocoupler U1 is grounded; pin 3 of the optocoupler U1 is connected to the first input end of the self-locking protection circuit 5, and pin 4 of the optocoupler U1 is connected to the second input end of the self-locking protection circuit 5.

[0021] The self-locking protection circuit 5 includes a resistor R1, a resistor R2, a resistor R3, a capacitor C1, a capacitor C2, a diode D1, a transistor Q1 and a MOS transistor Q2, wherein the cathode of the diode D1 is connected to one end of the capacitor C1, one end of the resistor R2, the base of the transistor Q1 and the drain of the MOS transistor Q2, and the connection point is connected to the isolation control circuit 4 as the first input end of the self-locking protection circuit 5; the anode of the diode D1 is connected to the control pin EN of the DCDC power module as the output end of the self-locking protection circuit 5 The other end of the capacitor C1 is connected to one end of the resistor R1, the other end of the resistor R2, and the emitter of the transistor Q1; the other end of the resistor R1 is connected to the positive power supply terminal VIN+ of the circuit of the present invention; the collector of the transistor Q1 is connected to one end of the capacitor C2, one end of the resistor R3, and the gate of the MOS tube Q2; the other end of the capacitor C2 is connected to the other end of the resistor R3 and the source of the MOS tube Q2, and the connection point is connected to the ground terminal VIN- as the second input terminal of the self-locking protection circuit 5 and the isolation control circuit 4.

[0022] In order to clearly understand the structure and overall operation of the present invention, the detailed working process of the present invention is described as follows: The current signal A is connected to the current sampling circuit 1 composed of the resistor R10, the resistor R11, the voltage regulator Z1 and the capacitor C3. The sampled signal is given to the signal amplifying circuit 2. The signal amplifying circuit 2 is used to amplify the obtained signal in a certain proportion and compare the amplified signal with the reference signal of the signal comparison circuit 3. When the amplified signal value is higher than the reference signal, the signal comparison circuit 3 outputs a high-level voltage, and the high-level voltage is transmitted to the isolation control circuit 4. The resistor R4 in the isolation control circuit 4 limits the current and then gives it to the optocoupler U1. The light-emitting diode inside the optocoupler U1 works to turn on the triode inside the optocoupler U1, thereby realizing the isolation control in the output overcurrent isolation self-locking protection circuit of the present invention. The isolation control circuit 4 transmits the control signal to the self-locking protection circuit 5. The diode D1 in the self-locking protection circuit 5 connects the power supply The control terminal EN of the module is pulled down to a low level, the DCDC power module is turned off at this time, the base of the transistor Q1 in the self-locking protection circuit 5 is also at a low level, the transistor Q1 works in the on state, the positive power supply terminal VIN+ passes through the transistor Q1 to the gate of the MOS tube Q2, at this time the gate of the MOS tube Q2 is at a high level, the MOS tube Q2 works in the on state, and the control terminal EN of the DCDC power module connected to the diode D1 is also pulled down to a low level, and the base of the transistor Q1 is also pulled down to a low level, if the overcurrent signal A is cancelled at this time, since there is always a voltage at the positive power supply terminal VIN+, the transistor Q1 and the MOS tube Q2 will always be in the on state, the EN terminal of the DCDC power module connected to the diode D1 is also always at a low level, and the DCDC power module is in the off state. Only after the positive power supply terminal VIN+ is turned off and then powered on again, the self-locking protection circuit 5 will be released from the working state, thereby realizing the self-locking protection function in the output overcurrent isolation self-locking protection circuit of the present invention.

[0023] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be thought of by any technician familiar with the field within the technical scope disclosed by the present invention without creative work should be covered within the protection scope of the present invention.

Claims

1. A DCDC power module output overcurrent self-locking isolation protection circuit, comprising a current sampling circuit (1) and a signal amplification circuit (2), characterized in that: It also includes a signal comparison circuit (3), an isolation control circuit (4) and a self-locking protection circuit (5), wherein the input end of the current sampling circuit (1) is connected to the output end of the DCDC power module, the current sampling circuit (1), the signal amplification circuit (2), the signal comparison circuit (3), the isolation control circuit (4) and the self-locking protection circuit (5) are connected in sequence, and the output end of the self-locking protection circuit (5) is connected to the control pin of the DCDC power module; The current sampling circuit (1) is used to collect the signal of the output current of the DCDC power module; the signal amplifying circuit (2) is used to amplify the signal obtained by the current sampling circuit (1); the signal comparing circuit (3) is used to compare the signal amplified by the signal amplifying circuit (2) with a reference signal, and transmit the signal obtained after the comparison to the isolation control circuit (4); the isolation control circuit (4) is used to generate a control signal according to the signal obtained after the comparison sent by the signal comparing circuit (3), and transmit the control signal to the self-locking protection circuit (5); the self-locking protection circuit (5) is used to control the self-locking protection circuit (5) with the control signal of the isolation control circuit (4), so as to realize self-locking when an overcurrent signal comes.

2. The DCDC power module output overcurrent self-locking isolation protection circuit according to claim 1, characterized in that: The current sampling circuit (1) comprises a resistor R10, a resistor R11, a voltage regulator Z1 and a capacitor C3, wherein one end of the resistor R10 is connected to one end of the resistor R11, and the connection point is connected to the output end of the DCDC power supply module as the input end of the current sampling circuit (1); the other end of the resistor R10 is commonly connected to one end of the voltage regulator Z1 and one end of the capacitor C3, and the connection point is commonly connected to the input end of the signal amplification circuit (2) as the input end of the current sampling circuit (1); the other end of the resistor R11, the other end of the voltage regulator Z1 and the other end of the capacitor C3 are commonly grounded.

3. The DCDC power module output overcurrent self-locking isolation protection circuit according to claim 1, characterized in that: The signal amplification circuit (2) comprises an operational amplifier U3, a resistor R8 and a resistor R9, wherein the pin 3 of the operational amplifier U3 is connected to the output end of the current sampling circuit (1) as the input end of the signal amplification circuit (2); the pin 4 of the operational amplifier U3 is connected to one end of the resistor R8 and one end of the resistor R9; the pin 2 of the operational amplifier U3 is connected to the first input end of the signal comparison circuit (3) as the first output end of the signal amplification circuit (2); the other end of the resistor R8 is connected to the pin 1 of the operational amplifier U3, and the connection point is connected to the second input end of the signal comparison circuit (3) as the second output end of the signal amplification circuit (2); the pin 5 of the operational amplifier U3 is grounded.

4. The DCDC power module output overcurrent self-locking isolation protection circuit according to claim 1, characterized in that: The signal comparison circuit (3) comprises a resistor R5, a resistor R6, a resistor R7, a diode D2 and an operational amplifier U2, wherein one end of the resistor R6 is connected to pin 2 of the operational amplifier U2 and one end of the resistor R5, and the connection point is connected to the first output end of the signal amplification circuit (2) as the first input end of the signal comparison circuit (3); the other end of the resistor R6 is connected to one end of the resistor R7 and pin 4 of the operational amplifier U2, and the other end of the resistor R7 is grounded; pin 3 of the operational amplifier U2 is connected to the second output end of the signal amplification circuit (2) as the second input end of the signal comparison circuit (3); pin 5 of the operational amplifier U2 is grounded; pin 1 of the operational amplifier U2 is connected to one end of the resistor R5 and the anode of the diode D2, and the anode of the diode D2 is connected to the input end of the isolation control circuit (4) as the output end of the signal comparison circuit (3).

5. The DCDC power module output overcurrent self-locking isolation protection circuit according to claim 1, characterized in that: The isolation control circuit (4) comprises a resistor R4 and an optocoupler U1, wherein one end of the resistor R4 is connected to the output end of the signal comparison circuit (3) as the input end of the isolation control circuit (4); the other end of the resistor R4 is connected to pin 1 of the optocoupler U1; pin 2 of the optocoupler U1 is grounded; pin 3 of the optocoupler U1 is connected to the first input end of the self-locking protection circuit (5); and pin 4 of the optocoupler U1 is connected to the second input end of the self-locking protection circuit (5).

6. The DCDC power module output overcurrent self-locking isolation protection circuit according to claim 1, characterized in that: The self-locking protection circuit (5) comprises a resistor R1, a resistor R2, a resistor R3, a capacitor C1, a capacitor C2, a diode D1, a transistor Q1 and a MOS transistor Q2, wherein the cathode of the diode D1 is commonly connected to one end of the capacitor C1, one end of the resistor R2, the base of the transistor Q1 and the drain of the MOS transistor Q2, and the connection point is connected to the isolation control circuit (4) as the first input end of the self-locking protection circuit (5); the anode of the diode D1 is connected to the DCDC circuit as the output end of the self-locking protection circuit (5). The control pin of the source module is connected; the other end of the capacitor C1 is connected to one end of the resistor R1, the other end of the resistor R2, and the emitter of the transistor Q1; the other end of the resistor R1 is connected to the input positive terminal; the collector of the transistor Q1 is connected to one end of the capacitor C2, one end of the resistor R3, and the gate of the MOS transistor Q2; the other end of the capacitor C2 is connected to the other end of the resistor R3 and the source of the MOS transistor Q2, and the connection point is connected to the ground terminal together with the isolation control circuit (4) as the second input terminal of the self-locking protection circuit (5).

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