Input terminal protection circuit and power conversion device

Abstract

The present invention mainly discloses an input protection circuit with a function of quickly shutting off a discharge path, which is applied to a DC-DC converter having a DC-DC conversion module and an input capacitor, and is used to couple between the input capacitor and a DC power source, and mainly includes a discharge circuit cutoff unit and a control unit. When the DC-DC converter is working normally, the control unit controls the discharge circuit cutoff unit according to at least one reference signal to form a channel, so that the input capacitor is coupled to the DC power source through the channel. When the input end of the DC-DC converter is short-circuited, the control unit controls the discharge circuit cutoff unit according to at least one reference signal to disconnect the channel, cut off the coupling between the input capacitor and the DC power source, and block the discharge circuit of the input capacitor when the input end is short-circuited, thereby maintaining the output voltage of the DC-DC converter from decreasing within a holding time.

Description

Technical Field

[0001] The present invention relates to the technical field of power converters, and more particularly to an input protection circuit with a function of quickly shutting off a discharge path and a power conversion device having the input protection circuit. Background Art

[0002] As we all know, railway transportation can be regarded as a national basic transportation construction. In order to cope with changes in climate, temperature, terrain, and power supply conditions, Europe has formulated the EN50155 regulations for the test standards of train electrical equipment. Other countries have formulated their own train electrical equipment test standards based on the EN50155 regulations.

[0003] In the power supply system of railway trains, a DC-DC converter plays a very important role. It is used to perform a voltage conversion process on the DC power provided by the generator, thereby supplying DC power with corresponding voltage values ​​to various load devices in the train. Figure 1 A block diagram showing a conventional DC-DC converter used in a train power supply system. Figure 1 As shown, the conventional DC-DC converter 1' mainly includes an input terminal protection unit 11' and a DC-DC conversion module 12'. The input terminal protection unit 11' is coupled between an input voltage signal and the DC-DC conversion module 12', and includes a diode D1' and an input capacitor Cin'. In addition, the DC-DC conversion module 12' has a first input terminal +Vin, a second input terminal -Vin, a first output terminal +Vout, and a second output terminal -Vout. In more detail, the diode D1' is used to prevent the input power supply from being reversely connected, and the input capacitor Cin' is usually an aluminum electrolytic capacitor, which is used to stabilize and filter the input DC power passing through the diode D1'.

[0004] EN50155 requires that the DC-DC converter 1' must comply with the S2 and S3 specifications when the input voltage signal is abnormal. If the output voltage of the DC-DC converter 1' can remain stable during the entire process in which the input voltage signal level suddenly drops to 0V and returns to normal after 10mS, the DC-DC converter 1' complies with the S2 specification. On the other hand, if the output voltage of the DC-DC converter 1' can remain stable during the entire process in which the input voltage signal level suddenly drops to 0V and returns to normal after 20mS, the DC-DC converter 1' complies with the S3 specification.

[0005] In practical applications, the output voltage holding time can be determined by designing the capacitance value of the input capacitor Cin' so that the DC-DC converter 1' complies with the S2 and / or S3 specifications. Figure 1 It can be seen that the input voltage signal includes VIN+ and VIN-. Practical experience shows that when the DC-DC conversion module 12' has an input short circuit fault, the VIN- level in the input voltage signal will rise rapidly, thereby accelerating the discharge of the input capacitor Cin', thereby causing the output voltage holding time to decrease, causing the DC-DC converter 1' to fail to meet the S2 and / or S3 specifications.

[0006] From the above description, it can be seen that the input protection unit 11' included in the conventional DC-DC converter 1' still has room for further improvement. In view of this, the inventor of the present invention has made great efforts to research and create, and finally developed an input protection circuit with a function of quickly shutting off the discharge path of the present invention. Summary of the invention

[0007] The main purpose of the present invention is to provide an input protection circuit with a function of quickly shutting off a discharge path, which is applied to a DC-DC converter having a DC-DC conversion module and an input capacitor, and is used to couple between the input capacitor and a DC power source, and mainly includes a discharge circuit cutoff unit and a control unit. According to the design of the present invention, when the DC-DC converter works normally, the control unit controls the discharge circuit cutoff unit to form a channel according to at least one reference signal, so that the input capacitor is coupled to the DC power source through the channel. In addition, when the input end of the DC-DC converter is short-circuited, the control unit controls the discharge circuit cutoff unit to disconnect the channel according to at least one reference signal, thereby cutting off the coupling between the input capacitor and the DC power source.

[0008] With such a design, when a short circuit occurs at the input end of the DC-DC converter, a discharge loop (discharge path) of the input capacitor will be blocked, thereby maintaining the output voltage of the DC-DC converter from decreasing within a holding time, so that the DC-DC converter can comply with S2 and / or S3 specifications.

[0009] To achieve the above-mentioned object, the present invention proposes a first embodiment of an input terminal protection circuit with a function of quickly shutting down a discharge path, which is applied to a DC-DC converter, wherein the DC-DC converter has a DC-DC conversion module and an input capacitor, the DC-DC conversion module has a first input terminal coupled to a first power supply terminal of a DC power source and a second input terminal coupled to a ground terminal, and the input capacitor is coupled between the first input terminal and the second input terminal with a first terminal and a second terminal; wherein the input terminal protection circuit comprises:

[0010] a discharge circuit cutoff unit coupled between a second power supply terminal of the DC power supply and the second terminal of the input capacitor; and

[0011] a control unit, coupled to the discharge loop cutoff unit, the second end of the input capacitor, the ground end, and a reference signal;

[0012] Wherein, when the DC-DC converter works normally, the control unit controls the discharge circuit cutoff unit to form a channel according to the reference signal, so that the second end of the input capacitor is coupled to the second power supply end of the DC power source through the channel of the discharge circuit cutoff unit;

[0013] When the input end of the DC-DC converter is short-circuited, the control unit controls the discharge circuit cutoff unit to disconnect the channel according to the reference signal, thereby cutting off the coupling between the second end of the input capacitor and the second power supply end of the DC power supply.

[0014] Furthermore, the discharge circuit cutoff unit comprises:

[0015] A MOSFET component having a drain terminal, a source terminal, and a gate terminal;

[0016] A first diode, with an anode terminal and a cathode terminal thereof respectively coupled to a drain terminal of the MOSFET component and a first terminal of the first capacitor;

[0017] a first capacitor, having a first terminal coupled to a cathode terminal of the first diode and a second terminal coupled to a source terminal of the MOSFET component; and

[0018] A first resistor is connected in parallel with the first capacitor.

[0019] Furthermore, the control unit comprises:

[0020] An operational amplifier having a positive input terminal, a negative input terminal, a positive bias terminal, a negative bias terminal, and an output terminal, wherein the positive input terminal is coupled to the reference signal, the negative input terminal is coupled to the drain terminal of the MOSFET component, the positive bias terminal is coupled to an operating voltage, and the negative bias terminal is coupled to the ground terminal;

[0021] a BJT component having a base terminal, an emitter terminal and a collector terminal, wherein the base terminal is coupled to the output terminal of the operational amplifier, the collector terminal is coupled to the ground terminal, and the emitter terminal is coupled to the gate terminal of the MOSFET component through an emitter resistor; and

[0022] A second resistor has one end coupled to the operating voltage and the other end coupled to the base terminal of the BJT component.

[0023] Furthermore, the BJT component is a PNP-type BTJ component, and the operational amplifier is a comparator or an error amplifier.

[0024] Furthermore, the reference signal is a reference voltage signal or a ground voltage signal.

[0025] Furthermore, the input terminal protection circuit further includes:

[0026] a first filter comprising a third resistor and a second capacitor, wherein the third resistor is coupled between the reference signal and the ground terminal, and the second capacitor is connected in parallel with the third resistor;

[0027] a second filter comprising a fourth resistor and a third capacitor, wherein the fourth resistor is coupled between the negative input terminal of the operational amplifier and the ground terminal, and the third capacitor is connected in parallel with the fourth resistor;

[0028] a fourth capacitor coupled between the second end of the input capacitor and the operating voltage;

[0029] a fifth resistor coupled between the emitter resistor and the gate terminal of the MOSFET component;

[0030] a sixth resistor, coupled between the emitter resistor and the second end of the first capacitor;

[0031] a seventh resistor, coupled between the emitter resistor and the operating voltage;

[0032] an eighth resistor coupled between the drain terminal of the MOSFET element and the negative bias terminal of the operational amplifier; and

[0033] A ninth resistor is coupled between the positive input terminal of the operational amplifier and the reference signal.

[0034] The present invention also discloses a power conversion device, which includes a DC-DC converter having a DC-DC conversion module and an input capacitor, and further includes the first embodiment of the input terminal protection circuit with a fast shut-off discharge path function of the present invention as described above.

[0035] To achieve the above-mentioned object, the present invention also proposes a second embodiment of an input terminal protection circuit with a function of quickly shutting down a discharge path, which is applied to a DC-DC converter, wherein the DC-DC converter has a DC-DC conversion module and an input capacitor, the DC-DC conversion module has a first input terminal coupled to a first power supply terminal of a DC power source and a second input terminal coupled to a ground terminal, and the input capacitor is coupled between the first input terminal and the second input terminal with a first terminal and a second terminal; wherein the input terminal protection circuit includes:

[0036] a discharge circuit cutoff unit coupled between a second power supply terminal of the DC power supply and the second terminal of the input capacitor; and

[0037] a control unit, coupled to the discharge loop cutoff unit, the second end of the input capacitor, the ground end, and a reference signal;

[0038] Wherein, when the DC-DC converter works normally, the control unit controls the discharge circuit cutoff unit to form a channel according to the reference signal, so that the second end of the input capacitor is coupled to the second power supply end of the DC power source through the channel of the discharge circuit cutoff unit;

[0039] When the input end of the DC-DC converter is short-circuited, the control unit controls the discharge circuit cutoff unit to disconnect the channel according to the reference signal, thereby cutting off the coupling between the second end of the input capacitor and the second power supply end of the DC power supply.

[0040] Furthermore, the control unit comprises:

[0041] An operational amplifier has a positive input terminal, a negative input terminal, a positive bias terminal, a negative bias terminal, and an output terminal, wherein the positive input terminal is coupled to the reference signal, the negative input terminal is coupled to the drain terminal of the MOSFET component, the positive bias terminal is coupled to an operating voltage, the negative bias terminal is coupled to the ground terminal, and the output terminal is coupled to the gate terminal of the MOSFET component.

[0042] Furthermore, the operational amplifier is a comparator or an error amplifier.

[0043] Furthermore, the reference signal is a reference voltage signal or a ground voltage signal.

[0044] Furthermore, the input terminal protection circuit also includes:

[0045] a first filter comprising a second resistor and a second capacitor, wherein the second resistor is coupled between the reference signal and the ground terminal, and the second capacitor is connected in parallel with the second resistor;

[0046] a second filter comprising a third resistor and a third capacitor, wherein the third resistor is coupled between the negative input terminal of the operational amplifier and the ground terminal, and the third capacitor is connected in parallel with the third resistor;

[0047] a fourth capacitor coupled between the second end of the input capacitor and the operating voltage; a fourth resistor coupled between the positive input end of the operational amplifier and the reference signal;

[0048] a fifth resistor coupled between the output terminal of the operational amplifier and the gate terminal of the MOSFET component;

[0049] a sixth resistor coupled between the fifth resistor and the second end of the first capacitor; and

[0050] A seventh resistor is coupled between the drain terminal of the MOSFET element and the negative input terminal of the operational amplifier.

[0051] The present invention also discloses a power conversion device, which includes a DC-DC converter having a DC-DC conversion module and an input capacitor, and further includes the second embodiment of the input terminal protection circuit with a fast shut-off discharge path function of the present invention as described above.

[0052] To achieve the above-mentioned object, the present invention proposes a third embodiment of an input terminal protection circuit with a function of quickly shutting down a discharge path, which is applied to a DC-DC converter, wherein the DC-DC converter has a DC-DC conversion module and an input capacitor, the DC-DC conversion module has a first input terminal coupled to a first power supply terminal of a DC power source and a second input terminal coupled to a ground terminal, and the input capacitor is coupled between the first input terminal and the second input terminal with a first terminal and a second terminal; wherein the input terminal protection circuit includes:

[0053] a common-mode inductor coupled to the first power supply terminal of the DC power supply and the first input terminal of the DC-DC conversion module, and also coupled between a second power supply terminal of the DC power supply and the second input terminal of the DC-DC conversion module;

[0054] a discharge circuit cutoff unit coupled between the second power supply terminal of the DC power supply and the common mode inductor;

[0055] a control unit, coupled to the discharge circuit cutoff unit, the first power supply end of the DC power supply, the ground end, and the first input end of the DC-DC conversion module;

[0056] Wherein, when the DC-DC converter is operating normally, the control unit controls the discharge circuit cutoff unit to form a channel according to a first reference signal sampled from the first power supply end of the DC power supply and a second reference signal sampled from the first input end of the DC-DC conversion module, so that the second end of the input capacitor is coupled to the second power supply end of the DC power supply through the channel of the discharge circuit cutoff unit;

[0057] Wherein, when the input end of the DC-DC converter is short-circuited, the control unit controls the discharge circuit cutoff unit to disconnect the channel based on a first reference signal sampled from the first power supply end of the DC power supply and a second reference signal sampled from the first input end of the DC-DC conversion module, thereby cutting off the coupling between the second end of the input capacitor and the second power supply end of the DC power supply.

[0058] Furthermore, the discharge circuit interruption unit comprises:

[0059] A MOSFET component having a drain terminal, a source terminal, and a gate terminal;

[0060] a first diode, with an anode terminal and a cathode terminal thereof respectively coupled to a drain terminal of the MOSFET component and a first terminal of the first capacitor;

[0061] a first capacitor, having a first terminal coupled to a cathode terminal of the first diode and a second terminal coupled to a source terminal of the MOSFET component; and

[0062] A first resistor is connected in parallel with the first capacitor.

[0063] Furthermore, the control unit comprises:

[0064] An operational amplifier has a positive input terminal, a negative input terminal, a positive bias terminal, a negative bias terminal, and an output terminal, wherein the positive input terminal is coupled to the first power supply terminal of the DC power supply, the negative input terminal is coupled to the drain terminal of the MOSFET component, the positive bias terminal is coupled to an operating voltage, the negative bias terminal is coupled to the ground terminal, and the output terminal is coupled to the first input terminal of the DC-DC conversion module.

[0065] Furthermore, the operational amplifier is a comparator or an error amplifier.

[0066] Furthermore, the input terminal protection circuit also includes:

[0067] a first sampling resistor, one end of which is coupled to the first power supply end of the DC power supply;

[0068] a first filter, comprising a second resistor and a second capacitor, wherein the second resistor is coupled between the other end of the first sampling resistor and the ground end, and the second capacitor is connected in parallel with the second resistor;

[0069] a second sampling resistor, with a first end thereof coupled to the first input end of the DC-DC conversion module;

[0070] a second filter, comprising a third resistor and a third capacitor, wherein the third resistor is coupled between a second end of the second sampling resistor and the ground end, and the third capacitor is connected in parallel with the third resistor;

[0071] a Zener diode, with a cathode end thereof coupled to the second end of the second sampling resistor, and an anode end thereof coupled to the ground end;

[0072] a fourth capacitor coupled to the working voltage and the ground terminal;

[0073] a fourth resistor coupled between the output terminal of the operational amplifier and the gate terminal of the MOSFET component;

[0074] a fifth resistor, coupled between the fourth resistor and the second end of the first capacitor;

[0075] a sixth resistor coupled between the drain terminal of the MOSFET device and the negative input terminal of the operational amplifier; and

[0076] A second diode is coupled between the sixth resistor and the negative input terminal of the operational amplifier.

[0077] The present invention also discloses a power conversion device, which includes a DC-DC converter having a DC-DC conversion module and an input capacitor, and further includes the third embodiment of the input terminal protection circuit with a fast shut-off discharge path function of the present invention as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0078] Figure 1 A block diagram of a prior art DC-DC converter used in a train power supply system;

[0079] Figure 2 A block diagram of a power conversion device having an input terminal protection circuit with a function of quickly shutting down a discharge path according to a first embodiment of the present invention;

[0080] Figure 3 The circuit topology diagram of the input terminal protection circuit with the function of quickly shutting off the discharge path according to the first embodiment of the present invention;

[0081] Figure 4A block diagram of a power conversion device having an input terminal protection circuit with a function of quickly shutting down a discharge path according to a second embodiment of the present invention;

[0082] Figure 5 FIG. 1 is a circuit topology diagram of an input terminal protection circuit with a function of quickly shutting off a discharge path according to a second embodiment of the present invention;

[0083] Figure 6 A block diagram of a power conversion device having an input terminal protection circuit with a function of quickly shutting down a discharge path according to a third embodiment of the present invention;

[0084] Figure 7 FIG. 4 is a circuit topology diagram of an input terminal protection circuit with a function of quickly shutting down a discharge path according to a third embodiment of the present invention.

[0085] Among them, the symbols or numbers in the figure and their corresponding component names are as follows:

[0086] 1, 2, 3: input end protection circuit; 11, 21, 31: discharge circuit cutoff unit;

[0087] 12, 22, 32: control unit; 13, 23, 33: first filter;

[0088] 14, 24, 34: second filter; 35: common mode inductor;

[0089] DCV: DC-DC conversion module; Cin: input capacitance;

[0090] +Vin: first input terminal; -Vin: second input terminal;

[0091] +Vout: first output terminal; -Vout: second output terminal;

[0092] VIN+: first power supply terminal; VIN-: second power supply terminal;

[0093] GND: ground terminal; Q1, Q1a, Q1b: MOSFET components;

[0094] C1, C1a, C1b: first capacitor; R1, R1a, R1b: first resistor;

[0095] D1, D1a, D1b: first diode; OP, OPa, OPb: operational amplifier;

[0096] Q2: BJT component; R2, R2a, R2b: second resistor;

[0097] C2, C2a, C2b: second capacitor; R3, R3a, R3b: third resistor;

[0098] C3, C3a, C3b: third capacitor; C4, C4a, C4b: fourth capacitor;

[0099] R5, R5a, R5b: fifth resistor; R6, R6a, R6b: sixth resistor;

[0100] R7, R7a: seventh resistor; R8: eighth resistor;

[0101] R9: the ninth resistor; R E : Emitter resistor;

[0102] R S1 : The first sampling resistor; R S2 : The second sampling resistor;

[0103] D2b: Zener diode; D3b: second diode;

[0104] 1': DC-DC converter; 11': input terminal protection unit;

[0105] 12': DC-DC conversion module; D1': diode;

[0106] Cin': input capacitance; +Vin': first input terminal;

[0107] -Vin': second input terminal; +Vout': first output terminal;

[0108] -Vout': second output terminal; GND': ground terminal DETAILED DESCRIPTION

[0109] In order to more clearly describe the input terminal protection circuit with the function of quickly shutting off the discharge path proposed by the present invention, the preferred embodiment of the present invention will be described in detail below with reference to the drawings.

[0110] First embodiment:

[0111] See also Figure 2 , which shows a block diagram of a power conversion device including an input terminal protection circuit with a fast shut-off discharge path function according to the present invention. Figure 2As shown, the power conversion device is a DC-DC converter, and the DC-DC converter has a DC-DC conversion module DCV and an input capacitor Cin. In more detail, the DC-DC conversion module DCV has a first input terminal +Vin, a second input terminal -Vin, a first output terminal +Vout, and a second output terminal -Vout; wherein the first input terminal +Vin is coupled to a first power supply terminal VIN+ of a DC power source, the second input terminal -Vin is coupled to a second input terminal -Vin of a ground terminal GND, and the first output terminal +Vout and the second output terminal -Vout are coupled to an external load device 3L. On the other hand, the input capacitor Cin is coupled between the first input terminal +Vin and the second input terminal -Vin with a first terminal and a second terminal.

[0112] In the first embodiment, the input protection circuit 1 includes: a discharge circuit interruption unit 11 and a control unit 12. Figure 2 As shown, the discharge circuit cutoff unit 11 is coupled between a second power supply terminal VIN- of the DC power supply and the second end of the input capacitor Cin, and the control unit 12 is simultaneously coupled to the discharge circuit cutoff unit 11, the second end of the input capacitor Cin, the ground terminal GND, and a reference signal. It is particularly noted that in the first embodiment, the reference signal may be a reference voltage signal V REF Furthermore, in a practical embodiment, the reference signal may also be a ground voltage signal (V GND ), that is, coupling it to the ground terminal GND.

[0113] According to the design of the present invention, Figure 2 As shown, when the DC-DC converter is working normally, the control unit 12 generates a signal based on the reference signal V REF / V GND The discharge circuit cutoff unit 11 is controlled to form a channel, so that the second end of the input capacitor Cin is coupled to the second power supply end VIN- of the DC power supply through the channel of the discharge circuit cutoff unit 11. It is worth noting that in the case of a short circuit at the input end of the DC-DC converter, the terminal voltage of the second power supply end VIN- of the DC power supply will rise rapidly; at this time, the control unit 12 controls the discharge circuit cutoff unit 11 to disconnect the channel according to the reference signal, thereby cutting off the coupling between the second end of the input capacitor Cin and the second power supply end VIN- of the DC power supply. In this way, a discharge circuit (discharge path) of the input capacitor will be blocked in the event of a short circuit at the input end, thereby maintaining the output voltage of the DC-DC converter from decreasing within a holding time, so that the DC-DC converter can meet the S2 and / or S3 specifications.

[0114] Continue to read Figure 2 , and please also refer to Figure 3 , which shows a circuit topology diagram of the input terminal protection circuit with the function of quickly shutting off the discharge path of the present invention. Figure 2 and Figure 3 As shown, in the first embodiment, the discharge circuit interruption unit 11 includes: a MOSFET component Q1, a first diode D1, a first capacitor C1 and a first resistor R1. In particular, the MOSFET component Q1 used in the present invention has a drain terminal, a source terminal and a gate terminal. An anode terminal and a cathode terminal of the first diode D1 are respectively coupled to a drain terminal of the MOSFET component Q1 and a first terminal of the first capacitor C1, a second terminal of the first capacitor C1 is coupled to a source terminal of the MOSFET component Q1, and the first resistor R1 is connected in parallel with the first capacitor C1.

[0115] In more detail, the control unit 12 mainly includes: an operational amplifier OP, a BJT component Q2 and a second resistor R2. It is particularly noted that in a feasible embodiment, the operational amplifier OP can be a comparator or an error amplifier, and the BJT component Q2 is a PNP type BTJ component. Figure 3 As shown, the operational amplifier OP has a positive input terminal, a negative input terminal, a positive bias terminal, a negative bias terminal, and an output terminal; wherein the positive input terminal is coupled to the reference signal (V REF / V GND ), the negative input terminal is coupled to the drain terminal of the MOSFET component Q1, and the positive bias terminal is coupled to a working voltage (V CC ), and the negative bias terminal is coupled to the ground terminal GND. On the other hand, the BJT element Q2 has a base terminal, an emitter terminal and a collector terminal, wherein the base terminal is coupled to the output terminal of the operational amplifier OP, the collector terminal is coupled to the ground terminal GND, and the emitter terminal is connected to the ground terminal GND through an emitter resistor R E The second resistor R2 has two terminals coupled to the gate terminal of the MOSFET component Q1. CC ) and the base terminal of the BJT component Q2.

[0116] It is additionally noted that if Figure 3As shown, in the case of a short circuit at the input end of the DC-DC converter, the terminal voltage of the second power supply terminal VIN- of the DC power supply will rise rapidly; at this time, the terminal voltage of the negative input end of the operational amplifier OP will be greater than the terminal voltage of its positive input end, so that the operational amplifier OP transmits a low-level signal to the BJT component Q2 through its output end, thereby quickly turning off the MOSFET component Q1. When the MOSFET component Q1 is turned off, a discharge loop (discharge path) of the input capacitor is blocked, so that the output voltage of the DC-DC converter will not drop within a holding time, so that the DC-DC converter can meet the S2 and / or S3 specifications. At the same time, the loop composed of the first diode D1, the first capacitor C1 and the first resistor R1 can absorb the voltage spike at the moment when the MOSFET component Q1 is turned off, preventing the MOSFET component Q1 from being damaged and playing a protective role. On the other hand, the control unit 11 also has the function of preventing the input power from being reversed. When the input power of the DC-DC converter is reversed, the MOSFET component Q1 is in a turned-off state, that is, the function of input power reverse protection is achieved.

[0117] It is worth noting that when the input terminal protection circuit 1 of the present invention is actually applied, Figure 3 As shown, a first filter 13, a second filter 14, a fourth capacitor C4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, and a ninth resistor R9 can be added to the circuit structure. Among them, the first filter 13 includes a third resistor R3 and a second capacitor C2, the third resistor R3 is coupled between the reference signal and the ground terminal GND, and the second capacitor C2 is connected in parallel with the third resistor R3. In addition, the second filter 14 includes a fourth resistor R4 and a third capacitor C3, the fourth resistor R4 is coupled between the negative input terminal of the operational amplifier OP and the ground terminal GND, and the third capacitor C3 is connected in parallel with the fourth resistor R4. Furthermore, the fourth capacitor C4 is coupled to the second end of the input capacitor Cin and the operating voltage (V CC ), the fifth resistor R5 is coupled to the emitter resistor R E The sixth resistor R6 is coupled to the emitter resistor R E The seventh resistor R7 is coupled to the emitter resistor R E With the working voltage (V CC ), the eighth resistor R8 is coupled between the drain terminal of the MOSFET component Q1 and the negative bias terminal of the operational amplifier OP, and the ninth resistor R9 is coupled between the positive input terminal of the operational amplifier OP and the reference signal.

[0118] Second embodiment

[0119] See also Figure 4 , which shows a block diagram of a power conversion device including an input protection circuit with a fast discharge path shutoff function according to the present invention. In the second embodiment, the input protection circuit 2 includes: a discharge loop cutoff unit 21 and a control unit 22. Figure 4 As shown, the discharge circuit cutoff unit 21 is coupled between a second power supply terminal VIN- of the DC power supply and the second end of the input capacitor Cin, and the control unit 22 is simultaneously coupled to the discharge circuit cutoff unit 21, the second end of the input capacitor Cin, the ground terminal GND, and the reference signal (V REF \V GND ).

[0120] According to the design of the present invention, Figure 4 As shown, when the DC-DC converter is working normally, the control unit 22 generates a signal based on the reference signal (V REF \V GND ) and controls the discharge circuit cutoff unit 21 to form a channel, so that the second end of the input capacitor Cin is coupled to the second power supply end VIN- of the DC power supply through the channel of the discharge circuit cutoff unit 21. It is worth noting that in the case of a short circuit at the input end of the DC-DC converter, the terminal voltage of the second power supply end VIN- of the DC power supply will rise rapidly; at this time, the control unit 22 controls the discharge circuit cutoff unit 21 to disconnect the channel according to the reference signal, thereby cutting off the coupling between the second end of the input capacitor Cin and the second power supply end VIN- of the DC power supply. In this way, a discharge circuit (discharge path) of the input capacitor will be blocked in the event of a short circuit at the input end, thereby maintaining the output voltage of the DC-DC converter from decreasing within a holding time, so that the DC-DC converter can meet the S2 and / or S3 specifications.

[0121] Continue to read Figure 4 , and please also refer to Figure 5 , which shows a circuit topology diagram of the input terminal protection circuit with the function of quickly shutting off the discharge path of the present invention. Figure 4 and Figure 5As shown, in the second embodiment, the discharge circuit interruption unit 21 includes: a MOSFET component Q1a, a first diode D1a, a first capacitor C1a and a first resistor R1a. In particular, the MOSFET component Q1a used in the present invention has a drain terminal, a source terminal and a gate terminal. An anode terminal and a cathode terminal of the first diode D1a are respectively coupled to a drain terminal of the MOSFET component Q1a and a first terminal of the first capacitor C1a, a second terminal of the first capacitor C1a is coupled to a source terminal of the MOSFET component Q1a, and the first resistor R1a is connected in parallel with the first capacitor C1a.

[0122] In particular, in the second embodiment, the control unit 22 only includes an operational amplifier OPa, which may be a comparator or an error amplifier. Figure 5 As shown, the operational amplifier OPa has a positive input terminal, a negative input terminal, a positive bias terminal, a negative bias terminal, and an output terminal. The positive input terminal is coupled to the reference signal (V REF \V GND ), the negative input terminal is coupled to the drain terminal of the MOSFET component Q1a, and the positive bias terminal is coupled to a working voltage (V CC ), the negative bias terminal is coupled to the ground terminal GND, and the output terminal is coupled to the gate terminal of the MOSFET component Q1a. It should be understood that in the case of a short circuit at the input terminal of the DC-DC converter, the terminal voltage of the second power supply terminal VIN- of the DC power supply will rise rapidly; at this time, the terminal voltage of the negative input terminal of the operational amplifier OPa will be greater than the terminal voltage of its positive input terminal, so that the operational amplifier OPa transmits a low-level signal to the gate terminal of the MOSFET component Q1a through its output terminal, thereby turning off the MOSFET component Q1a. When the MOSFET component Q1a is turned off, a discharge loop (discharge path) of the input capacitor is blocked, thereby maintaining the output voltage of the DC-DC converter from dropping within a holding time, so that the DC-DC converter can meet the S2 and / or S3 specifications. At the same time, the loop composed of the first diode D1a, the first capacitor C1a and the first resistor R1a can absorb the voltage spike at the moment when the MOSFET component Q1a is turned off, preventing the MOSFET component Q1 from being damaged, and playing a protective role. On the other hand, the control unit 11 also has the function of preventing the input power from being reversely connected. When the input power of the DC-DC converter is reversely connected, the MOSFET component Q1a is in the off state, that is, the input power reverse connection protection function is achieved.

[0123] It should be noted that in practical applications such as Figure 5When the input protection circuit 2 of the present invention is shown, a first filter 23, a second filter 24, a fourth capacitor C4a, a fourth resistor R4a, a fifth resistor R5a, a sixth resistor R6a, and a seventh resistor R7a can be added to the circuit structure. Among them, the first filter 23 includes a second resistor R2a and a second capacitor C2a, the second resistor R2a is coupled between the reference signal and the ground terminal GND, and the second capacitor C2a is connected in parallel with the second resistor R2a. On the other hand, the second filter 24 includes a third resistor R3a and a third capacitor C3a, the third resistor R3a is coupled between the negative input terminal of the operational amplifier OPa and the ground terminal GND, and the third capacitor C3a is connected in parallel with the third resistor R3a. Furthermore, the fourth capacitor C4a is coupled to the second end of the input capacitor Cin and the working voltage (V CC ), the fourth resistor R4a is coupled between the positive input terminal of the operational amplifier OPa and the reference signal, the fifth resistor R5a is coupled between the output terminal of the operational amplifier OPa and the gate terminal of the MOSFET component Q1a, the sixth resistor R6a is coupled between the fifth resistor R5a and the second terminal of the first capacitor C1a, and the seventh resistor R7a is coupled between the drain terminal of the MOSFET component Q1a and the negative input terminal of the operational amplifier OPa.

[0124] Third embodiment

[0125] See also Figure 6 , which shows a block diagram of a power conversion device including an input protection circuit with a fast discharge path shutoff function according to the present invention. In the third embodiment, the input protection circuit 3 includes: a common mode inductor 35, a discharge loop cutoff unit 31 and a control unit 32. Figure 6 As shown, the common-mode inductor 35 is coupled to the first power supply terminal VIN+ of the DC power supply and the first input terminal +Vin of the DC-DC conversion module DCV, and is also coupled between a second power supply terminal VIN- of the DC power supply and the second input terminal -Vin of the DC-DC conversion module DCV. On the other hand, the discharge loop cutoff unit 31 is coupled between the second power supply terminal VIN- of the DC power supply and the common-mode inductor 35, and the control unit 32 is also coupled to the discharge loop cutoff unit 31, the first power supply terminal VIN+ of the DC power supply, the ground terminal GND, and the first input terminal +Vin of the DC-DC conversion module DCV.

[0126] According to the design of the present invention, Figure 6As shown, when the DC-DC converter works normally, the control unit 32 controls the discharge circuit cutoff unit 31 to form a channel according to a first reference signal sampled from the first power supply terminal VIN+ of the DC power source and a second reference signal sampled from the first input terminal +Vin of the DC-DC conversion module DCV, so that the second end of the input capacitor Cin is coupled to the second power supply terminal VIN- of the DC power source through the channel of the discharge circuit cutoff unit 31. It is worth noting that when the input terminal of the DC-DC converter is short-circuited, the control unit 32 controls the discharge circuit cutoff unit 31 to disconnect the channel according to the first reference signal sampled from the first power supply terminal VIN+ of the DC power source and the second reference signal sampled from the first input terminal +Vin of the DC-DC conversion module DCV, thereby cutting off the coupling between the second end of the input capacitor Cin and the second power supply terminal VIN- of the DC power source. In this way, a discharge loop (discharge path) of the input capacitor will be blocked when a short circuit occurs at the input end, thereby maintaining the output voltage of the DC-DC converter from decreasing within a holding time, so that the DC-DC converter can comply with S2 and / or S3 specifications.

[0127] Continue to read Figure 6 , and please also refer to Figure 7 , which shows a circuit topology diagram of the input terminal protection circuit with the function of quickly shutting off the discharge path of the present invention. Figure 6 and Figure 7 As shown, in the third embodiment, the discharge circuit interruption unit 31 includes: a MOSFET component Q1b, a first diode D1b, a first capacitor C1b and a first resistor R1b. In particular, the MOSFET component Q1b used in the present invention has a drain terminal, a source terminal and a gate terminal. An anode terminal and a cathode terminal of the first diode D1b are respectively coupled to a drain terminal of the MOSFET component Q1b and a first terminal of the first capacitor C1a, a second terminal of the first capacitor C1b is coupled to a source terminal of the MOSFET component Q1b, and the first resistor R1b is connected in parallel with the first capacitor C1b.

[0128] In the third embodiment, the control unit 32 also includes only an operational amplifier OPb, which can be a comparator or an error amplifier, and has a positive input terminal, a negative input terminal, a positive bias terminal, a negative bias terminal, and an output terminal. The positive input terminal is coupled to the first power supply terminal VIN+ of the DC power supply, the negative input terminal is coupled to the first input terminal +Vin of the DC-DC conversion module DCV, and the positive bias terminal is coupled to a working voltage (V CC), the negative bias terminal is coupled to the ground terminal GND, and the output terminal is coupled to the gate terminal of the MOSFET component Q1b.

[0129] Compare Figure 5 and Figure 6 Afterwards, it should be understood that the circuit operation mode of the control unit 32 and the discharge circuit cutoff unit 31 in the third embodiment is substantially the same as the circuit operation mode of the control unit 22 and the discharge circuit cutoff unit 21 in the second embodiment. The only difference is that in the third embodiment, the positive input terminal and the negative input terminal of the operational amplifier OPb are respectively coupled to the first power supply terminal VIN+ of the DC power supply and the first input terminal +Vin of the DC-DC conversion module DCV. In other words, the positive input terminal of the operational amplifier OPb receives a first reference signal transmitted from the first power supply terminal VIN+ of the DC power supply, and the negative input terminal of the operational amplifier OPb receives a second reference signal transmitted from the first input terminal +Vin of the DC-DC conversion module DCV. Then, according to the first reference signal and the second reference signal, the operational amplifier OPb outputs a control signal to control the on / off of the MOSFET component Q1b.

[0130] Moreover, in practical applications such as Figure 7 When the input terminal protection circuit 3 of the present invention is shown, a first sampling resistor R can be added to the circuit structure. S1 , a first filter 33, a second sampling resistor R S2 , a second filter 34, a (voltage stabilizing) Zener diode D2b, a fourth capacitor C4b, a fourth resistor R4b, a fifth resistor R5b, a sixth resistor R6b, and a second diode D3b. Figure 7 As shown, the first sampling resistor R S1 One end of the first filter 33 is coupled to the first power supply terminal VIN+ of the DC power supply. In addition, the first filter 33 includes a second resistor R2b and a second capacitor C2b, wherein the second resistor R2b is coupled to the first sampling resistor R S1 The other end of the first filter 33 is connected to the ground terminal GND, and the second capacitor C2b is connected in parallel with the second resistor R2b. It should be understood that the second resistor R2b of the first filter 33 and the first sampling resistor R S1 A voltage-dividing resistor is formed, and the voltage-dividing resistor is used to sample a reference (voltage) signal at the first power supply terminal VIN+ of the DC power supply, so that the positive input terminal of the operational amplifier OPb can receive a first reference signal transmitted from the first power supply terminal VIN+ of the DC power supply.

[0131] According to the above description, the second sampling resistor R S2A first end is coupled to the first input end +Vin of the DC-DC conversion module DCV. In addition, the second filter 34 includes a third resistor R3b and a third capacitor C3b, wherein the third resistor R3b is coupled to the second sampling resistor R S2 and the ground terminal GND, and the third capacitor C3b is connected in parallel with the third resistor R3b. It should be understood that the third resistor R3b of the second filter 34 and the second sampling resistor R S2 A voltage-dividing resistor is also formed, so that a reference (voltage) signal is sampled at the first input terminal +Vin of the DC-DC conversion module DCV by using the voltage-dividing resistor, so that the negative input terminal of the operational amplifier OPb can receive a second reference signal transmitted from the first input terminal +Vin of the DC-DC conversion module DCV.

[0132] In more detail, the (voltage stabilizing) Zener diode D2b is coupled with the second sampling resistor R S2 The second end of the capacitor C4b is connected to the ground terminal GND. CC and the ground terminal GND, the fourth resistor R4b is coupled between the output terminal of the operational amplifier OPb and the gate terminal of the MOSFET component Q1b, the fifth resistor R5b is coupled between the fourth resistor R4a and the second terminal of the first capacitor C1b, the sixth resistor R6b is coupled between the drain terminal of the MOSFET component Q1b and the negative input terminal of the operational amplifier OPb, and the second diode D3b is coupled between the sixth resistor R6b and the negative input terminal of the operational amplifier OPb.

[0133] Thus, the above description has completely and clearly described all embodiments of an input protection circuit with a function of quickly shutting off a discharge path and a power conversion device with the input protection circuit disclosed in the present invention. It must be emphasized that the above detailed description is a specific description of a feasible embodiment of the present invention, but the embodiment is not used to limit the patent scope of the present invention. Any equivalent implementation or change that does not deviate from the technical spirit of the present invention should be included in the patent scope of this case.

Claims

1. An input protection circuit, applied to a DC-DC converter, characterized in that: The DC-DC converter comprises a DC-DC conversion module and an input capacitor, wherein the DC-DC conversion module comprises a first input terminal coupled to a first power supply terminal of a DC power source and a second input terminal coupled to a ground terminal, and the input capacitor is coupled between the first input terminal and the second input terminal with a first terminal and a second terminal; wherein the input terminal protection circuit comprises a discharge circuit cutoff unit and a control unit, wherein when the DC-DC converter works normally, the control unit controls the discharge circuit cutoff unit to form a channel according to at least one reference signal, so that the input capacitor is coupled to the DC power source through the channel; and, when the input terminal of the DC-DC converter is short-circuited, the control unit controls the discharge circuit cutoff unit to disconnect the channel according to at least one reference signal, thereby cutting off the coupling between the input capacitor and the DC power source; The discharge circuit cutoff unit is coupled between a second power supply terminal of the DC power supply and the second terminal of the input capacitor; The control unit is coupled to the discharge circuit cutoff unit, the second end of the input capacitor, the ground end, and the reference signal at the same time; Wherein, when the DC-DC converter works normally, the control unit controls the discharge circuit cutoff unit to form a channel according to the reference signal, so that the second end of the input capacitor is coupled to the second power supply end of the DC power supply through the channel of the discharge circuit cutoff unit; Wherein, in the case that the input end of the DC-DC converter is short-circuited, the control unit controls the discharge circuit cutoff unit to disconnect the channel according to the reference signal, thereby cutting off the coupling between the second end of the input capacitor and the second power supply end of the DC power supply; The discharge circuit cutoff unit comprises: A MOSFET component having a drain terminal, a source terminal, and a gate terminal; A first diode, with an anode terminal and a cathode terminal thereof respectively coupled to a drain terminal of the MOSFET component and a first terminal of the first capacitor; a first capacitor, having a first terminal coupled to a cathode terminal of the first diode and a second terminal coupled to a source terminal of the MOSFET component; and a first resistor connected in parallel with the first capacitor; The control unit comprises: An operational amplifier has a positive input terminal, a negative input terminal, a positive bias terminal, a negative bias terminal, and an output terminal, wherein the positive input terminal is coupled to the reference signal, the negative input terminal is coupled to the drain terminal of the MOSFET component, the positive bias terminal is coupled to an operating voltage, and the negative bias terminal is coupled to the ground terminal.

2. The input terminal protection circuit according to claim 1, characterized in that: The control unit also includes: An operational amplifier having a positive input terminal, a negative input terminal, a positive bias terminal, a negative bias terminal, and an output terminal, wherein the positive input terminal is coupled to the reference signal, the negative input terminal is coupled to the drain terminal of the MOSFET component, the positive bias terminal is coupled to an operating voltage, and the negative bias terminal is coupled to the ground terminal; a BJT component having a base terminal, an emitter terminal and a collector terminal, wherein the base terminal is coupled to the output terminal of the operational amplifier, the collector terminal is coupled to the ground terminal, and the emitter terminal is coupled to the gate terminal of the MOSFET component through an emitter resistor; and A second resistor has one end coupled to the operating voltage and the other end coupled to the base terminal of the BJT component.

3. The input terminal protection circuit according to claim 2, characterized in that: The BJT component is a PNP type BTJ component, and the operational amplifier is a comparator or an error amplifier.

4. The input terminal protection circuit according to claim 2, characterized in that: The reference signal is a reference voltage signal or a ground voltage signal.

5. The input terminal protection circuit according to claim 2, characterized in that: Also includes: a first filter comprising a third resistor and a second capacitor, wherein the third resistor is coupled between the reference signal and the ground terminal, and the second capacitor is connected in parallel with the third resistor; a second filter comprising a fourth resistor and a third capacitor, wherein the fourth resistor is coupled between the negative input terminal of the operational amplifier and the ground terminal, and the third capacitor is connected in parallel with the fourth resistor; a fourth capacitor coupled between the second end of the input capacitor and the operating voltage; a fifth resistor coupled between the emitter resistor and the gate terminal of the MOSFET component; a sixth resistor, coupled between the emitter resistor and the second end of the first capacitor; a seventh resistor, coupled between the emitter resistor and the operating voltage; an eighth resistor coupled between the drain terminal of the MOSFET element and the negative bias terminal of the operational amplifier; and A ninth resistor is coupled between the positive input terminal of the operational amplifier and the reference signal.

6. The input terminal protection circuit according to claim 1, characterized in that: The output terminal is coupled to the gate terminal of the MOSFET component.

7. The input terminal protection circuit according to claim 6, characterized in that: The operational amplifier is a comparator or an error amplifier.

8. The input terminal protection circuit according to claim 6, characterized in that: The reference signal is a reference voltage signal or a ground voltage signal.

9. The input terminal protection circuit according to claim 6, characterized in that: Also includes: a first filter comprising a second resistor and a second capacitor, wherein the second resistor is coupled between the reference signal and the ground terminal, and the second capacitor is connected in parallel with the second resistor; a second filter comprising a third resistor and a third capacitor, wherein the third resistor is coupled between the negative input terminal of the operational amplifier and the ground terminal, and the third capacitor is connected in parallel with the third resistor; a fourth capacitor coupled between the second end of the input capacitor and the operating voltage; a fourth resistor coupled between the positive input end of the operational amplifier and the reference signal; a fifth resistor coupled between the output terminal of the operational amplifier and the gate terminal of the MOSFET component; a sixth resistor coupled between the fifth resistor and the second end of the first capacitor; and A seventh resistor is coupled between the drain terminal of the MOSFET element and the negative input terminal of the operational amplifier.

10. An input terminal protection circuit, characterized in that: The DC-DC converter has a DC-DC conversion module and an input capacitor, wherein the DC-DC conversion module has a first input terminal coupled to a first power supply terminal of a DC power source and a second input terminal coupled to a ground terminal, and the input capacitor is coupled between the first input terminal and the second input terminal with a first terminal and a second terminal; wherein the input terminal protection circuit includes a discharge circuit cutoff unit and a control unit, wherein when the DC-DC converter works normally, the control unit controls the discharge circuit cutoff unit to form a channel according to at least one reference signal, so that the input capacitor is coupled to the DC power source through the channel; and, when the input terminal of the DC-DC converter is short-circuited, the control unit controls the discharge circuit cutoff unit to disconnect the channel according to at least one reference signal, thereby cutting off the coupling between the input capacitor and the DC power source; The input terminal protection circuit further includes: a common-mode inductor coupled to a first power supply terminal of the DC power supply and a first input terminal of the DC-DC conversion module, and also coupled between a second power supply terminal of the DC power supply and a second input terminal of the DC-DC conversion module; The discharge circuit cutoff unit is coupled between the second power supply terminal of the DC power supply and the common mode inductor; The control unit is coupled to the discharge circuit cutoff unit, the first power supply terminal of the DC power supply, the ground terminal, and the first input terminal of the DC-DC conversion module; Wherein, when the DC-DC converter works normally, the control unit controls the discharge circuit cutoff unit to form a channel according to a first reference signal sampled from the first power supply end of the DC power supply and a second reference signal sampled from the first input end of the DC-DC conversion module, so that the second end of the input capacitor is coupled to the second power supply end of the DC power supply through the channel of the discharge circuit cutoff unit; Wherein, when an input terminal of the DC-DC converter is short-circuited, the control unit controls the discharge circuit cutoff unit to disconnect the channel based on the first reference signal sampled from the first power supply terminal of the DC power supply and the second reference signal sampled from the first input terminal of the DC-DC conversion module, thereby cutting off the coupling between the second terminal of the input capacitor and the second power supply terminal of the DC power supply.

11. The input terminal protection circuit according to claim 10, characterized in that: The discharge circuit cutoff unit comprises: A MOSFET component having a drain terminal, a source terminal, and a gate terminal; A first diode, with an anode terminal and a cathode terminal thereof respectively coupled to a drain terminal of the MOSFET component and a first terminal of the first capacitor; a first capacitor, having a first terminal coupled to a cathode terminal of the first diode and a second terminal coupled to a source terminal of the MOSFET component; and A first resistor is connected in parallel with the first capacitor.

12. The input terminal protection circuit according to claim 11, characterized in that: The control unit comprises: An operational amplifier has a positive input terminal, a negative input terminal, a positive bias terminal, a negative bias terminal, and an output terminal, wherein the positive input terminal is coupled to the first power supply terminal of the DC power supply, the negative input terminal is coupled to the drain terminal of the MOSFET component, the positive bias terminal is coupled to an operating voltage, the negative bias terminal is coupled to the ground terminal, and the output terminal is coupled to the first input terminal of the DC-DC conversion module.

13. The input terminal protection circuit according to claim 12, characterized in that: The operational amplifier is a comparator or an error amplifier.

14. The input terminal protection circuit according to claim 12, characterized in that: Also includes: a first sampling resistor, one end of which is coupled to the first power supply end of the DC power supply; a first filter, comprising a second resistor and a second capacitor, wherein the second resistor is coupled between the other end of the first sampling resistor and the ground end, and the second capacitor is connected in parallel with the second resistor; a second sampling resistor, with a first end thereof coupled to the first input end of the DC-DC conversion module; a second filter, comprising a third resistor and a third capacitor, wherein the third resistor is coupled between a second end of the second sampling resistor and the ground end, and the third capacitor is connected in parallel with the third resistor; a Zener diode, with a cathode end thereof coupled to the second end of the second sampling resistor, and an anode end thereof coupled to the ground end; a fourth capacitor coupled to the working voltage and the ground terminal; a fourth resistor coupled between the output terminal of the operational amplifier and the gate terminal of the MOSFET component; a fifth resistor, coupled between the fourth resistor and the second end of the first capacitor; a sixth resistor coupled between the drain terminal of the MOSFET device and the negative input terminal of the operational amplifier; and A second diode is coupled between the sixth resistor and the negative input terminal of the operational amplifier.

15. A power conversion device, comprising a DC-DC converter having a DC-DC conversion module and an input capacitor, characterized in that: The power conversion device comprises the input terminal protection circuit according to any one of claims 1 to 5.

16. A power conversion device, comprising a DC-DC converter having a DC-DC conversion module and an input capacitor, characterized in that: The power conversion device includes an input terminal protection circuit as claimed in any one of claims 6 to 9.

17. A power conversion device, comprising a DC-DC converter having a DC-DC conversion module and an input capacitor, characterized in that: The power conversion device comprises the input terminal protection circuit according to any one of claims 10 to 14.

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