Direct-current power supply input circuit and pre-charging circuit

Abstract

The utility model provides a direct-current power supply input circuit and a pre-charging circuit, the pre-charging circuit can be applied to the direct-current power supply input circuit, and a first end of a comparison unit in the circuit serves as a control input end of the pre-charging circuit; the second end of the comparison unit is connected with the first end of the charging unit; a third end of the comparison unit is used as a cathode input end of the pre-charging circuit and is connected to an input cathode of the direct-current power supply input circuit; the second end of the charging unit serves as the positive electrode input end of the pre-charging circuit and is connected to the input positive electrode of the direct-current power supply input circuit, and the third end of the charging unit serves as the charging output end of the pre-charging circuit and is connected to the parallel positive electrode of a voltage stabilizing capacitor in the direct-current power supply input circuit. The first triode is conducted to promote the second triode to be conducted so as to pre-charge the parallel positive electrode of the voltage stabilizing capacitor, and the problems that an existing circuit adopts a power device with very small on-resistance as a switch tube for reducing series impedance of the capacitor, the size is large, cost is high, and circuit reliability is low are solved.

Description

Technical Field

[0001] The present application relates to the technical field of electronic circuits, and in particular to a direct current power supply input circuit and a pre-charging circuit. Background Art

[0002] With the development of society, people's demand for battery-based DC power supply applications is also increasing. In order to stabilize the voltage, a large number of electrolytic capacitors are usually connected to the DC input to store energy. When the input is powered on, a lot of impact current will be generated, causing sparks.

[0003] In order to avoid the occurrence of sparking, a pre-charging circuit is needed to slowly charge the subsequent capacitor when the input is powered on to suppress the generation of large current.

[0004] like Figure 1 As shown, the existing pre-charging circuit mainly connects all electrolytic capacitors in series with a power resistor, and slowly charges the capacitor through the resistor. When the capacitor is fully charged, the power tube in parallel with the resistor is turned on to short-circuit the resistor. Although this method can effectively control the impact of the impact of the capacitor's impact current, in order to reduce the series impedance of the capacitor, the switch tube needs a power device with a very small on-resistance. This device is large in size and high in cost. At the same time, the switch tube is required to be in a working state all the time, and the circuit reliability is low. Utility Model Content

[0005] In this regard, the present application provides a DC power supply input circuit and a pre-charging circuit to solve the problem that the existing circuit uses a power device with very small on-resistance as a switch tube to reduce the series impedance of the capacitor, which has large size, high cost and low circuit reliability.

[0006] To achieve the above objectives, the present application provides the following technical solutions:

[0007] In a first aspect, the present application discloses a pre-charging circuit, which is applied to a DC power supply input circuit. The pre-charging circuit includes: a comparison unit and a charging unit;

[0008] The first end of the comparison unit serves as the control input end of the pre-charging circuit to receive the pre-charging control voltage; the second end of the comparison unit is connected to the first end of the charging unit; the third end of the comparison unit serves as the negative input end of the pre-charging circuit to be connected to the negative input end of the DC power supply input circuit; the second end of the charging unit serves as the positive input end of the pre-charging circuit to be connected to the positive input end of the DC power supply input circuit; the third end of the charging unit serves as the charging output end of the pre-charging circuit to be connected to the parallel positive end of the voltage-stabilizing capacitor in the DC power supply input circuit;

[0009] When the pre-charge control voltage is greater than the turn-on voltage of the first transistor in the comparison unit, the first transistor is turned on to cause the second transistor in the charging unit to be turned on, so as to pre-charge the parallel positive electrode of the voltage-stabilizing capacitor.

[0010] Optionally, in the above-mentioned pre-charging circuit, the comparison unit includes: a first base resistor, a first current limiting resistor and the first transistor;

[0011] One end of the first base resistor serves as the first end of the comparison unit, the other end of the first base resistor is respectively connected to one end of the first current limiting resistor and the base of the first transistor, the collector of the first transistor serves as the second end of the comparison unit, the emitter of the first transistor is connected to the other end of the first current limiting resistor, and the connection point serves as the third end of the comparison unit.

[0012] Optionally, in the above-mentioned pre-charging circuit, the charging unit includes: a second base resistor, a second current limiting resistor, the second transistor and a buffer suppression resistor;

[0013] One end of the second base resistor is connected to the emitter of the second transistor, and the connection point serves as the second end of the charging unit. The other end of the second base resistor is respectively connected to the base of the second transistor and one end of the second current limiting resistor, and the other end of the second current limiting resistor serves as the first end of the charging unit. The collector of the second transistor is connected to one end of the buffer suppression resistor, and the other end of the buffer suppression resistor serves as the third end of the charging unit.

[0014] Optionally, the above-mentioned pre-charging circuit also includes: a control circuit, wherein the input end of the control circuit is connected to the positive input terminal of the DC power supply input circuit, and the output end of the control circuit is connected to the control input end of the pre-charging circuit to output the pre-charging control voltage.

[0015] Optionally, in the above-mentioned pre-charging circuit, the control circuit includes: a first capacitor, a second capacitor and a first resistor;

[0016] One end of the first capacitor is connected to one end of the second capacitor, and the connection point serves as the input end of the control circuit; the other end of the first capacitor is respectively connected to the other end of the second capacitor and one end of the first resistor, and the other end of the first resistor serves as the output end of the control circuit.

[0017] Optionally, in the above-mentioned pre-charging circuit, it further includes: an MCU, wherein an output terminal of the MCU is connected to a control input terminal of the pre-charging circuit, and outputs the pre-charging control voltage;

[0018] Among them, when the output end of the MCU outputs a high level, the pre-charge control voltage is greater than the conduction voltage of the first transistor, and when the output end of the MCU outputs a low level, the pre-charge control voltage is less than the conduction voltage of the first transistor.

[0019] The second aspect of the present application discloses a DC power supply input circuit, comprising: an anti-reverse protection unit, an input sampling unit, a voltage stabilizing unit, an output sampling unit, a unidirectional cut-off unit, and a pre-charging circuit as disclosed in any one of the first aspects;

[0020] The anti-reverse protection unit, the input sampling unit, the pre-charging circuit, the voltage stabilizing unit and the output sampling unit are connected in parallel in sequence, and the two ends of the parallel connection are respectively connected to the input positive electrode of the DC power supply input circuit and the input negative electrode of the DC power supply input circuit, and the unidirectional cut-off unit is connected in series to the input positive electrode branch between the pre-charging circuit and the voltage stabilizing unit.

[0021] Optionally, in the above-mentioned DC power supply input circuit, the first end of the anti-reverse protection unit, the first end of the input sampling unit, the positive input end of the pre-charging circuit, the first end of the voltage stabilizing unit and the first end of the output sampling unit are connected, and the connection point is connected to the input positive electrode of the DC power supply input circuit as one end in parallel;

[0022] The second end of the anti-reverse protection unit, the second end of the input sampling unit, the negative input end of the pre-charging circuit, the second end of the voltage stabilizing unit and the second end of the output sampling unit are connected, and the connection point is connected to the input negative electrode of the DC power supply input circuit as the other end of the parallel connection.

[0023] Optionally, in the above-mentioned DC power supply input circuit, the anti-reverse protection unit includes: a common cathode diode, the cathode of the common cathode diode serves as the first end of the anti-reverse protection unit; the first anode and the second anode of the common cathode diode are connected, and the connection point serves as the second end of the anti-reverse protection unit;

[0024] The input sampling unit comprises: a thirteenth resistor, a fourteenth resistor and a third capacitor;

[0025] One end of the thirteenth resistor serves as the first end of the input sampling unit, and the other end of the thirteenth resistor is respectively connected to one end of the fourteenth resistor and one end of the third capacitor, and the connection point outputs the input sampling voltage; the other end of the fourteenth resistor is connected to the other end of the third capacitor, and the connection point serves as the second end of the input sampling unit;

[0026] The one-way cut-off unit includes: a first power tube, a second power tube, a third power tube, a fourth power tube, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor and a tenth resistor;

[0027] The drain of the first power tube is respectively connected to the drain of the second power tube, the drain of the third power tube and the drain of the fourth power tube, and serves as a first connection point; the source of the first power tube is respectively connected to the source of the second power tube, the source of the third power tube, the source of the fourth power tube, one end of the third resistor, one end of the fourth resistor, one end of the fifth resistor and one end of the sixth resistor, and serves as a second connection point, and the first connection point and the second connection point are connected in series to the input positive electrode branch between the pre-charging circuit and the voltage stabilizing unit;

[0028] The gate of the first power tube is respectively connected to the other end of the third resistor and one end of the seventh resistor; the gate of the second power tube is respectively connected to the other end of the fourth resistor and one end of the eighth resistor; the gate of the third power tube is respectively connected to the other end of the fifth resistor and one end of the ninth resistor; the gate of the fourth power tube is respectively connected to the other end of the sixth resistor and one end of the tenth resistor;

[0029] The other end of the seventh resistor is respectively connected to the other end of the eighth resistor, the other end of the ninth resistor and the other end of the tenth resistor, and the connection points receive a cut-off signal;

[0030] The voltage stabilizing unit comprises: a first voltage stabilizing capacitor and a second voltage stabilizing capacitor;

[0031] The positive electrode of the first voltage-stabilizing capacitor is connected to the positive electrode of the second voltage-stabilizing capacitor, and the connection point serves as the first end of the voltage-stabilizing unit; the negative electrode of the first voltage-stabilizing capacitor is connected to the negative electrode of the second voltage-stabilizing capacitor, and the connection point serves as the second end of the voltage-stabilizing unit;

[0032] The output sampling unit comprises: an eleventh resistor, a twelfth resistor and a fourth capacitor;

[0033] One end of the eleventh resistor serves as the first end of the output sampling unit, and the other end of the eleventh resistor is respectively connected to one end of the twelfth resistor and one end of the fourth capacitor, and the connection point outputs the output sampling voltage; the other end of the twelfth resistor is connected to the other end of the fourth capacitor, and the connection point serves as the second end of the output sampling unit.

[0034] Optionally, in the above-mentioned DC power supply input circuit, it further includes: an input terminal, through which the input positive electrode of the DC power supply input circuit and the input negative electrode of the DC power supply input circuit are connected to a DC power supply;

[0035] And / or, a fuse, wherein the fuse is arranged at a subsequent stage of the input terminal and is connected in series between an input positive electrode of the DC power supply input circuit and an input negative electrode of the DC power supply input circuit.

[0036] The pre-charging circuit provided in the present application can be applied to a DC power supply input circuit, and the pre-charging circuit includes: a comparison unit and a charging unit; the first end of the comparison unit serves as a control input end of the pre-charging circuit to receive a pre-charging control voltage; the second end of the comparison unit is connected to the first end of the charging unit; the third end of the comparison unit serves as a negative input end of the pre-charging circuit and is connected to the input negative electrode of the DC power supply input circuit; the second end of the charging unit serves as a positive input end of the pre-charging circuit and is connected to the input positive electrode of the DC power supply input circuit, and the third end of the charging unit serves as a charging output end of the pre-charging circuit and is connected to the parallel positive electrode of the voltage-stabilizing capacitor in the DC power supply input circuit; when the pre-charging control voltage is greater than the conduction voltage of the first transistor in the comparison unit, the first transistor is turned on to cause the second transistor in the charging unit to be turned on to pre-charge the parallel positive electrode of the voltage-stabilizing capacitor, which can effectively prevent excessive input current from impacting and sparking, and solves the problem that the existing circuit uses a power device with a very small on-resistance as a switch tube to reduce the series impedance of the capacitor, which has a large volume, high cost and low circuit reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0038] Figure 1 A circuit diagram of an existing pre-charging circuit provided in an embodiment of the present application;

[0039] Figure 2 and Figure 3 A schematic diagram of the structures of two pre-charging circuits provided in an embodiment of the present application;

[0040] Figure 4 A circuit diagram of a pre-charging circuit provided in an embodiment of the present application;

[0041] Figure 5 A schematic diagram of the structure of a pre-charging circuit provided in an embodiment of the present application;

[0042] Figure 6 A circuit diagram of a DC power supply input circuit provided in an embodiment of the present application. DETAILED DESCRIPTION

[0043] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0044] First of all, it should be noted that Figure 1 , the electrolytic capacitors are capacitors C56 and C57 in the figure, the power resistor is R38, and the power tube is Q26.

[0045] The present application provides a pre-charging circuit to solve the problem that the existing circuit uses a power device with very small on-resistance as a switch tube to reduce the series impedance of the capacitor, which has large size, high cost and low circuit reliability.

[0046] See also Figure 2 The pre-charging circuit can be applied to a DC power supply input circuit and may include: a comparing unit 101 and a charging unit 102 .

[0047] Among them, the first end of the comparison unit 101 serves as the control input end of the pre-charging circuit to receive the pre-charging control voltage; the second end of the comparison unit 101 is connected to the first end of the charging unit 102; the third end of the comparison unit 101 serves as the negative input end of the pre-charging circuit and is connected to the negative input end of the DC power supply input circuit (BAT- in the figure); the second end of the charging unit 102 serves as the positive input end of the pre-charging circuit and is connected to the positive input end of the DC power supply input circuit (BAT+ in the figure); the third end of the charging unit 102 serves as the charging output end of the pre-charging circuit and is connected to the parallel positive electrode of the voltage-stabilizing capacitor in the DC power supply input circuit.

[0048] When the pre-charge control voltage is greater than the turn-on voltage of the first transistor in the comparison unit 101, the first transistor is turned on to cause the second transistor in the charging unit 102 to be turned on, so as to pre-charge the parallel positive electrode of the voltage-stabilizing capacitor.

[0049] In some embodiments, Figure 4As shown, the comparison unit 101 may include: a first base resistor R45, a first current limiting resistor R46 and a first transistor Q10; wherein, one end of the first base resistor R45 serves as the first end of the comparison unit 101, the other end of the first base resistor R45 is respectively connected to one end of the first current limiting resistor R46 and the base of the first transistor Q10, the collector of the first transistor Q10 serves as the second end of the comparison unit 101, the emitter of the first transistor Q10 is connected to the other end of the first current limiting resistor R46, and the connection point serves as the third end of the comparison unit 101.

[0050] In actual applications, the first base resistor R45 in the comparison unit 101 can be used to generate a driving voltage corresponding to the first transistor Q10 according to the input pre-charge control voltage; the first current limiting resistor R46 can discharge the base of the first transistor Q10 to avoid the base of the first transistor Q10 being subjected to a higher voltage when it does not need to be turned on.

[0051] It should be noted that the first transistor Q10 can be a small-signal NPN transistor; of course, it is not limited to this, and can also be determined according to the application environment and user needs. This application does not limit it and it is within the protection scope of this application.

[0052] Exemplarily, the model of the first base resistor R45 may be 427AR, the model of the first current limiting resistor R46 may be 103CR, and the model of the first transistor Q10 may be LABT4401LTIG.

[0053] In some embodiments, Figure 4 As shown, the charging unit 102 may include: a second base resistor R40, a second current limiting resistor R32, a second triode Q5 and a buffer suppression resistor R27; wherein, one end of the second base resistor R40 is connected to the emitter of the second triode Q5, and the connection point serves as the second end of the charging unit 102, the other end of the second base resistor R40 is respectively connected to the base of the second triode Q5 and one end of the second current limiting resistor R32, the other end of the second current limiting resistor R32 serves as the first end of the charging unit 102, the collector of the second triode Q5 is connected to one end of the buffer suppression resistor R27, and the other end of the buffer suppression resistor R27 serves as the third end of the charging unit 102.

[0054] In actual applications, the second base resistor R40 in the charging unit 102 can be used to generate a driving voltage corresponding to the second transistor Q5 according to the voltage of the collector of the first transistor Q10; the second current limiting resistor R32 can discharge the base of the second transistor Q5 to prevent the base of the second transistor Q5 from being subjected to a higher voltage when it does not need to be turned on.

[0055] It should be noted that the second transistor Q5 can be a PNP transistor; of course, it is not limited to this, and can also be determined according to the application environment and user needs. This application does not limit it and it is within the protection scope of this application.

[0056] Exemplarily, the model of the second base resistor R40 may be 203R, the model of the second current limiting resistor R32 may be 103CR, and the model of the second transistor Q5 may be 2SB1124.

[0057] In combination with the above, it can be understood that the pre-charging circuit mainly includes: a comparison unit 101 and a charging unit 102. Among them, the first end of the comparison unit 101 is used as the control input end of the pre-charging circuit to receive the pre-charging control voltage, the second end of the comparison unit 101 is connected to the first end of the charging unit 102, and the third end of the comparison unit 101 is used as the negative input end of the pre-charging circuit, connected to the input negative pole of the DC power supply input circuit; the second end of the charging unit 102 is used as the positive input end of the pre-charging circuit, connected to the input positive pole of the DC power supply input circuit; the third end of the charging unit 102 is used as the charging output end of the pre-charging circuit, connected to the parallel positive pole of the voltage-stabilizing capacitor in the DC power supply input circuit; when the pre-charging control voltage is greater than the conduction voltage of the first transistor Q10 in the comparison unit 101, the first transistor Q10 and the second transistor Q5 in the charging unit 102 are both turned on, and the pre-charging circuit charges the voltage-stabilizing capacitor through the buffer suppression resistor R27 in the charging unit 102.

[0058] In practical applications, the pre-charge control voltage can be generated by the control circuit 103 or the MCU 104 , that is, the control method of the pre-charge circuit provided in the present application can be controlled by the control circuit 103 or by the MCU 104 .

[0059] In some embodiments, Figure 3 As shown, the pre-charging circuit may also include a control circuit 103, wherein the input end of the control circuit 103 is connected to the positive input terminal of the DC power supply input circuit, and the output end of the control circuit 103 is connected to the control input end of the pre-charging circuit to output a pre-charging control voltage.

[0060] like Figure 4 As shown, the control circuit 103 mainly includes: a first capacitor C77, a second capacitor C78 and a first resistor R34; wherein, one end of the first capacitor C77 is connected to one end of the second capacitor C78, ​​and the connection point serves as the input end of the control circuit 103; the other end of the first capacitor C77 is respectively connected to the other end of the second capacitor C78 and one end of the first resistor R34, and the other end of the first resistor R34 serves as the output end of the control circuit 103.

[0061] It should be noted that after the DC power supply input circuit is powered on, the control circuit 103 composed of the first capacitor C77, the second capacitor C78 and the first resistor R34 can output a pre-charge control voltage, that is, it can provide a conduction current for the comparison unit 101. When the pre-charge control voltage is greater than the conduction voltage of the first transistor Q10 in the comparison unit 101, the first transistor Q10 and the second transistor Q5 in the charging unit 102 are both turned on, and the voltage-stabilizing capacitor of the subsequent stage in the DC power supply input circuit can be pre-charged; when the pre-charge control voltage output by the control circuit 103 is not sufficient to maintain the conduction of the first transistor Q10, the pre-charge ends automatically.

[0062] In some embodiments, Figure 5 As shown, the pre-charging circuit may further include an MCU104, wherein the output end of the MCU104 is connected to the control input end of the pre-charging circuit, and outputs a pre-charging control voltage; wherein, when the output end of the MCU104 outputs a high level, the pre-charging control voltage is greater than the conduction voltage of the first transistor Q10, and when the output end of the MCU104 outputs a low level, the pre-charging control voltage is less than the conduction voltage of the first transistor Q10.

[0063] It should be noted that, after the DC power supply input circuit is powered on, the output terminal of the MCU104 can be controlled to output a high level, the first transistor Q10 in the comparison unit 101 can be controlled to be turned on, and then the second transistor Q5 in the charging unit 102 can be controlled to be turned on, and the voltage stabilizing capacitor is pre-charged through the buffer suppression resistor R27. When the output sampling voltage output by the output sampling unit 207 in the DC power supply input circuit reaches a preset value, the output terminal of the MCU104 is controlled to output a low level, and then the first transistor Q10 and the second transistor Q5 are controlled to be disconnected, and the pre-charging ends.

[0064] It is worth noting that compared with using the output of MCU104 as the pre-charge control voltage, using the output of the control circuit 103 as the pre-charge control voltage can achieve automatic pre-charging, that is, automatic pre-charging when the DC power supply current is powered on, and automatically ending the pre-charging when the first capacitor C77 and the second capacitor C78 are fully charged.

[0065] It should also be noted that the voltage stabilizing capacitor in the DC power supply input circuit can be a large-capacity capacitor arranged at the rear stage of the pre-charging circuit, such as Figures 2 to 4 The capacitors C56, C57 and the subsequent parallel capacitors, these large-capacity capacitors are mainly used to stabilize the fluctuation of the input voltage. The positive poles of these large-capacity capacitors in parallel serve as the parallel positive poles of the voltage-stabilizing capacitors.

[0066] In summary, the pre-charging circuit provided in this embodiment can be applied to a DC power supply input circuit, and the pre-charging circuit includes: a comparison unit 101 and a charging unit 102; the first end of the comparison unit 101 serves as a control input end of the pre-charging circuit to receive a pre-charging control voltage; the second end of the comparison unit 101 is connected to the first end of the charging unit 102; the third end of the comparison unit 101 serves as a negative input end of the pre-charging circuit to be connected to the negative input end of the DC power supply input circuit; the second end of the charging unit 102 serves as a positive input end of the pre-charging circuit to be connected to the positive input end of the DC power supply input circuit The third end of the charging unit 102 is used as the charging output end of the pre-charging circuit and is connected to the parallel positive electrode of the voltage-stabilizing capacitor in the DC power supply input circuit; when the pre-charging control voltage is greater than the turn-on voltage of the first transistor Q10 in the comparison unit 101, the first transistor Q10 is turned on to cause the second transistor Q5 in the charging unit 102 to be turned on, so as to pre-charge the parallel positive electrode of the voltage-stabilizing capacitor, which can effectively prevent the impact of excessive input current from sparking, and solves the problem that the existing circuit uses a power device with a very small on-resistance as a switch tube to reduce the series impedance of the capacitor, which has the problems of large size, high cost and low circuit reliability.

[0067] Based on the pre-charging circuit provided in the above embodiment, optionally, another embodiment of the present application further provides a DC power supply input circuit, see Figure 6 The DC power supply input circuit mainly includes: an anti-reverse protection unit 202, an input sampling unit 203, a voltage stabilizing unit 206, an output sampling unit 207, a unidirectional cut-off unit 205 and a pre-charging circuit 204 as described in any of the above embodiments.

[0068] The anti-reverse protection unit 202, the input sampling unit 203, the pre-charging circuit 204, the voltage stabilizing unit 206 and the output sampling unit 207 are connected in parallel in sequence, and the two ends of the parallel connection are respectively connected to the input positive pole of the DC power supply input circuit and the input negative pole of the DC power supply input circuit, and the unidirectional cut-off unit 205 is connected in series to the input positive pole branch between the pre-charging circuit 204 and the voltage stabilizing unit 206.

[0069] In some embodiments, the first end of the anti-reverse protection unit 202, the first end of the input sampling unit 203, the positive input end of the pre-charging circuit 204, the first end of the voltage stabilizing unit 206, and the first end of the output sampling unit 207 are connected, and the connection point is connected to the positive input of the DC power supply input circuit as one end of the parallel connection; the second end of the anti-reverse protection unit 202, the second end of the input sampling unit 203, the negative input end of the pre-charging circuit 204, the second end of the voltage stabilizing unit 206, and the second end of the output sampling unit 207 are connected, and the connection point is connected to the negative input of the DC power supply input circuit as the other end of the parallel connection.

[0070] In practical applications, such as Figure 6As shown, the DC power supply input circuit may further include: an input terminal J1, and an input positive electrode of the DC power supply input circuit and an input negative electrode of the DC power supply input circuit are connected to a DC power supply through the input terminal J1. The input positive electrode of the DC power supply input circuit is connected to the positive electrode of the DC power supply through pin 2 of the input terminal J1, and the input negative electrode of the DC power supply input circuit is connected to the negative electrode of the DC power supply through pin 1 of the input terminal J1.

[0071] Specifically, the specific model of the input terminal J1 may be CON_396_2; of course, it is not limited thereto, and other existing input terminals J1 may be selected depending on the application environment and user needs. This application does not limit this, and all are within the protection scope of this application.

[0072] Combination Figure 6 The anti-reverse protection unit 202 mainly includes: a common cathode diode D14, a cathode 3 of the common cathode diode D14 serves as a first end of the anti-reverse protection unit 202; a first anode 1 and a second anode 2 of the common cathode diode D14 are connected, and the connection point serves as a second end of the anti-reverse protection unit 202.

[0073] It should be noted that by connecting the cathode 3 of the common cathode diode D14 to the positive input pole of the DC power supply input circuit, and connecting the first anode 1 and the second anode 2 of the common cathode diode D14 to the negative input pole of the DC power supply input circuit respectively, the reverse flow of current can be prevented, thereby protecting other circuits or devices from the influence of reverse current.

[0074] Combination Figure 6 , the input sampling unit 203 may include: a thirteenth resistor R36, a fourteenth resistor R48 and a third capacitor C60.

[0075] Among them, one end of the thirteenth resistor R36 serves as the first end of the input sampling unit 203, and the other end of the thirteenth resistor R36 is respectively connected to one end of the fourteenth resistor R48 and one end of the third capacitor C60, and the connection point outputs the input sampling voltage; the other end of the fourteenth resistor R48 is connected to the other end of the third capacitor C60, and the connection point serves as the second end of the input sampling unit 203.

[0076] For example, the specific model of the thirteenth resistor R36 may be 2002AR, the specific model of the fourteenth resistor R48 may be 102CR, and the specific model of the third capacitor C60 may be 103CHXD.

[0077] It should be noted that the input sampling unit 203 composed of the thirteenth resistor R36, the fourteenth resistor R48 and the third capacitor C60 can implement sampling of the input voltage of the DC power supply input circuit.

[0078] Combination Figure 6 The unidirectional cut-off unit 205 may include: a first power tube Q3, a second power tube Q4, a third power tube Q6, a fourth power tube Q9, a third resistor R24, a fourth resistor R26, a fifth resistor R30, a sixth resistor R39, a seventh resistor R25, an eighth resistor R28, a ninth resistor R35 and a tenth resistor R44.

[0079] The drain of the first power tube Q3 is respectively connected to the drain of the second power tube Q4, the drain of the third power tube Q6 and the drain of the fourth power tube Q9, and serves as a first connection point; the source of the first power tube Q3 is respectively connected to the source of the second power tube Q4, the source of the third power tube Q6, the source of the fourth power tube Q9, one end of the third resistor R24, one end of the fourth resistor R26, one end of the fifth resistor R30 and one end of the sixth resistor R39, and serves as a second connection point. The first connection point and the second connection point are connected in series to the input positive electrode branch between the pre-charging circuit 204 and the voltage stabilizing unit 206; the first power tube Q The gates of the second power tube Q3 are respectively connected to the other end of the third resistor R24 ​​and one end of the seventh resistor R25; the gates of the second power tube Q4 are respectively connected to the other end of the fourth resistor R26 and one end of the eighth resistor R28; the gates of the third power tube Q6 are respectively connected to the other end of the fifth resistor R30 and one end of the ninth resistor R35; the gates of the fourth power tube Q9 are respectively connected to the other end of the sixth resistor R39 and one end of the tenth resistor R44; the other end of the seventh resistor R25 is respectively connected to the other end of the eighth resistor R28, the other end of the ninth resistor R35 and the other end of the tenth resistor R44, and the connection points receive the cut-off signal.

[0080] In practical applications, the on / off states of the first power tube Q3, the second power tube Q4, the third power tube Q6, and the fourth power tube Q9 can be controlled by the cut-off signal to control whether the one-way cut-off unit 205 is in the cut-off state. When the cut-off signal is at a high level, the one-way cut-off unit 205 can be controlled to be in the cut-off state, and when the cut-off signal is at a low level, the one-way cut-off unit 205 can be controlled not to be in the cut-off state.

[0081] It should be noted that the cut-off signal can be determined based on the output sampling voltage sampled by the output sampling unit 207 in the DC power supply input circuit. When the output sampling voltage is greater than the preset value, that is, it indicates that the DC power supply input circuit has reached a stable state after powering on, the output can control the unidirectional cut-off unit 205 to be in a high-level signal in the on state; conversely, when the output sampling voltage is not greater than the preset value, that is, it indicates that the DC power supply input circuit has not yet reached a stable state after powering on, the output can control the unidirectional cut-off unit 205 to be in a low-level signal in the off state.

[0082] Exemplarily, the specific models of the first power tube Q3, the second power tube Q4, the third power tube Q6 and the fourth power tube Q9 can be SFS08R03GNF, the specific models of the third resistor R24, the fourth resistor R26, the fifth resistor R30 and the sixth resistor R39 can be 103CR, and the specific models of the seventh resistor R25, the eighth resistor R28, the ninth resistor R35 and the tenth resistor R44 can be 221AR.

[0083] Combination Figure 6 The voltage stabilizing unit 206 mainly includes: a first voltage stabilizing capacitor C56 and a second voltage stabilizing capacitor C57.

[0084] Among them, the positive electrode of the first voltage-stabilizing capacitor C56 is connected to the positive electrode of the second voltage-stabilizing capacitor C57, and the connection point serves as the first end of the voltage-stabilizing unit 206. The negative electrode of the first voltage-stabilizing capacitor C56 is connected to the negative electrode of the second voltage-stabilizing capacitor C57, and the connection point serves as the second end of the voltage-stabilizing unit 206.

[0085] It should be noted that, by providing the first voltage stabilizing capacitor C56C56 and the second voltage stabilizing capacitor C57 in the DC power supply input circuit, the distribution of voltage and current in the circuit can be adjusted, thereby improving the power supply stability of the DC power supply input circuit.

[0086] Exemplarily, the operating voltage of the first stabilizing capacitor C56 and the second stabilizing capacitor C57 may be: 180 μF / 60V.

[0087] Combination Figure 6 The output sampling unit 207 may include: an eleventh resistor R37, a twelfth resistor R47 and a fourth capacitor C61.

[0088] Among them, one end of the eleventh resistor R37 serves as the first end of the output sampling unit 207, and the other end of the eleventh resistor R37 is respectively connected to one end of the twelfth resistor R47 and one end of the fourth capacitor C61, and the connection point outputs the output sampling voltage; the other end of the twelfth resistor R47 is connected to the other end of the fourth capacitor C61, and the connection point serves as the second end of the output sampling unit 207.

[0089] It should be noted that the output sampling unit 207 formed by the eleventh resistor R37 , the twelfth resistor R47 and the fourth capacitor C61 can implement sampling of the output voltage of the DC power supply input circuit.

[0090] For example, the specific model of the eleventh resistor R37 may be 2002AR, the specific model of the twelfth resistor R47 may be 102CR, and the specific model of the fourth capacitor C61 may be 103CHXD.

[0091] In some embodiments, see also Figure 6The DC power supply input circuit may further include: a fuse F1, which is arranged at the rear stage of the input terminal J1 and is connected in series between the input positive electrode of the DC power supply input circuit and the input negative electrode of the DC power supply input circuit.

[0092] In practical applications, after setting the fuse F1 after the input terminal J1, when the current output by the DC power supply exceeds the limit of the fuse F1, the fuse F1 can be melted to disconnect the circuit, thereby avoiding the influence of the current exceeding the limit on the DC power supply input circuit and subsequent devices.

[0093] Exemplarily, the operating voltage of fuse F1 may be 63A / 65V.

[0094] It should be noted that, combined with Figure 6 The pre-charging circuit 204 can be specifically arranged between the pre-charging circuit 204 and the voltage stabilizing unit 206, that is, connected in series with the input positive branch between the pre-charging circuit 204 and the voltage stabilizing unit 206, which can charge the subsequent voltage stabilizing capacitor when the DC power supply input circuit is powered on to prevent sparking caused by excessive input current impact.

[0095] It should also be noted that, for the relevant description of the pre-charging circuit 204, please refer to the corresponding embodiment above, which will not be repeated here. For the DC power supply input circuit, please refer to the prior art, which will not be repeated here one by one.

[0096] In this embodiment, after the pre-charging circuit 204 is added to the DC power supply input circuit, the subsequent voltage stabilizing capacitor can be pre-charged when the DC power supply input circuit is powered on to prevent sparking caused by excessive input impact current.

[0097] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

[0098] It should also be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

Claims

1. A pre-charging circuit, characterized in that: Applied to a DC power supply input circuit, the pre-charging circuit comprises: a comparison unit and a charging unit; The first end of the comparison unit serves as the control input end of the pre-charging circuit to receive the pre-charging control voltage; the second end of the comparison unit is connected to the first end of the charging unit; the third end of the comparison unit serves as the negative input end of the pre-charging circuit to be connected to the negative input end of the DC power supply input circuit; the second end of the charging unit serves as the positive input end of the pre-charging circuit to be connected to the positive input end of the DC power supply input circuit; the third end of the charging unit serves as the charging output end of the pre-charging circuit to be connected to the parallel positive end of the voltage-stabilizing capacitor in the DC power supply input circuit; When the pre-charge control voltage is greater than the turn-on voltage of the first transistor in the comparison unit, the first transistor is turned on to cause the second transistor in the charging unit to be turned on, so as to pre-charge the parallel positive electrode of the voltage-stabilizing capacitor.

2. The precharge circuit according to claim 1, characterized in that The comparison unit comprises: a first base resistor, a first current limiting resistor and the first transistor; One end of the first base resistor serves as the first end of the comparison unit, the other end of the first base resistor is respectively connected to one end of the first current limiting resistor and the base of the first transistor, the collector of the first transistor serves as the second end of the comparison unit, the emitter of the first transistor is connected to the other end of the first current limiting resistor, and the connection point serves as the third end of the comparison unit.

3. The precharge circuit according to claim 1, characterized in that: The charging unit comprises: a second base resistor, a second current limiting resistor, the second transistor and a buffer suppression resistor; One end of the second base resistor is connected to the emitter of the second transistor, and the connection point serves as the second end of the charging unit. The other end of the second base resistor is respectively connected to the base of the second transistor and one end of the second current limiting resistor, and the other end of the second current limiting resistor serves as the first end of the charging unit. The collector of the second transistor is connected to one end of the buffer suppression resistor, and the other end of the buffer suppression resistor serves as the third end of the charging unit.

4. The precharge circuit according to claim 1, characterized in that: Also includes: A control circuit, wherein the input end of the control circuit is connected to the positive input terminal of the DC power supply input circuit, and the output end of the control circuit is connected to the control input end of the pre-charge circuit to output the pre-charge control voltage.

5. The precharge circuit according to claim 4, characterized in that: The control circuit includes: a first capacitor, a second capacitor and a first resistor; One end of the first capacitor is connected to one end of the second capacitor, and the connection point serves as the input end of the control circuit; the other end of the first capacitor is respectively connected to the other end of the second capacitor and one end of the first resistor, and the other end of the first resistor serves as the output end of the control circuit.

6. The precharge circuit according to claim 1, characterized in that: Also includes: MCU, The output end of the MCU is connected to the control input end of the pre-charging circuit to output the pre-charging control voltage; Among them, when the output end of the MCU outputs a high level, the pre-charge control voltage is greater than the conduction voltage of the first transistor, and when the output end of the MCU outputs a low level, the pre-charge control voltage is less than the conduction voltage of the first transistor.

7. A DC power supply input circuit, characterized in that: include: An anti-reverse protection unit, an input sampling unit, a voltage stabilizing unit, an output sampling unit, a unidirectional cut-off unit, and a pre-charging circuit as claimed in any one of claims 1 to 6; The anti-reverse protection unit, the input sampling unit, the pre-charging circuit, the voltage stabilizing unit and the output sampling unit are connected in parallel in sequence, and the two ends of the parallel connection are respectively connected to the input positive electrode of the DC power supply input circuit and the input negative electrode of the DC power supply input circuit, and the unidirectional cut-off unit is connected in series to the input positive electrode branch between the pre-charging circuit and the voltage stabilizing unit.

8. The DC power supply input circuit according to claim 7, characterized in that: The first end of the anti-reverse protection unit, the first end of the input sampling unit, the positive input end of the pre-charging circuit, the first end of the voltage stabilizing unit and the first end of the output sampling unit are connected, and the connection point is connected to the input positive electrode of the DC power supply input circuit as one end in parallel; The second end of the anti-reverse protection unit, the second end of the input sampling unit, the negative input end of the pre-charging circuit, the second end of the voltage stabilizing unit and the second end of the output sampling unit are connected, and the connection point is connected to the input negative electrode of the DC power supply input circuit as the other end of the parallel connection.

9. The DC power supply input circuit according to claim 7, characterized in that: The anti-reverse protection unit comprises: a common cathode diode, the cathode of the common cathode diode serves as the first end of the anti-reverse protection unit; a first anode and a second anode of the common cathode diode are connected, and the connection point serves as the second end of the anti-reverse protection unit; The input sampling unit comprises: a thirteenth resistor, a fourteenth resistor and a third capacitor; One end of the thirteenth resistor serves as the first end of the input sampling unit, and the other end of the thirteenth resistor is respectively connected to one end of the fourteenth resistor and one end of the third capacitor, and the connection point outputs the input sampling voltage; the other end of the fourteenth resistor is connected to the other end of the third capacitor, and the connection point serves as the second end of the input sampling unit; The one-way cut-off unit includes: a first power tube, a second power tube, a third power tube, a fourth power tube, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor and a tenth resistor; The drain of the first power tube is respectively connected to the drain of the second power tube, the drain of the third power tube and the drain of the fourth power tube, and serves as a first connection point; the source of the first power tube is respectively connected to the source of the second power tube, the source of the third power tube, the source of the fourth power tube, one end of the third resistor, one end of the fourth resistor, one end of the fifth resistor and one end of the sixth resistor, and serves as a second connection point, and the first connection point and the second connection point are connected in series to the input positive electrode branch between the pre-charging circuit and the voltage stabilizing unit; The gate of the first power tube is respectively connected to the other end of the third resistor and one end of the seventh resistor; the gate of the second power tube is respectively connected to the other end of the fourth resistor and one end of the eighth resistor; the gate of the third power tube is respectively connected to the other end of the fifth resistor and one end of the ninth resistor; the gate of the fourth power tube is respectively connected to the other end of the sixth resistor and one end of the tenth resistor; The other end of the seventh resistor is respectively connected to the other end of the eighth resistor, the other end of the ninth resistor and the other end of the tenth resistor, and the connection points receive a cut-off signal; The voltage stabilizing unit comprises: a first voltage stabilizing capacitor and a second voltage stabilizing capacitor; The positive electrode of the first voltage-stabilizing capacitor is connected to the positive electrode of the second voltage-stabilizing capacitor, and the connection point serves as the first end of the voltage-stabilizing unit; the negative electrode of the first voltage-stabilizing capacitor is connected to the negative electrode of the second voltage-stabilizing capacitor, and the connection point serves as the second end of the voltage-stabilizing unit; The output sampling unit comprises: an eleventh resistor, a twelfth resistor and a fourth capacitor; One end of the eleventh resistor serves as the first end of the output sampling unit, and the other end of the eleventh resistor is respectively connected to one end of the twelfth resistor and one end of the fourth capacitor, and the connection point outputs the output sampling voltage; the other end of the twelfth resistor is connected to the other end of the fourth capacitor, and the connection point serves as the second end of the output sampling unit.

10. The DC power supply input circuit according to claim 7, characterized in that: Also includes: An input terminal, through which the input positive electrode of the DC power supply input circuit and the input negative electrode of the DC power supply input circuit are connected to a DC power source; And / or, a fuse, wherein the fuse is arranged at a subsequent stage of the input terminal and is connected in series between an input positive electrode of the DC power supply input circuit and an input negative electrode of the DC power supply input circuit.

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