A discharge device with a pre-connection undervoltage protection function

Abstract

The present invention provides a discharge device with a pre-connection undervoltage protection function, comprising: a discharge circuit and a pre-connection undervoltage protection circuit, the latter comprising: a first, a second, and a third circuit. The input end of the first circuit is connected to an external power supply; the input end of the second circuit is connected to the output end of the first circuit and the positive pole of the input end of the discharge circuit; the third circuit is connected to the external power supply, the positive pole of the input end of the discharge circuit, and the output end of the second circuit; when the device is connected to an external power supply, the input voltage Vin+ of the device gradually rises, and during the rising process, when Vin+ < V 一级 , the pre-connection undervoltage protection circuit does not supply power to the discharge circuit; when Vin+ ≥ V 一级 , the external power supply is connected to the positive pole of the input end of the discharge circuit and the input end of the second circuit through the first circuit, and the input voltage of the discharge circuit is greater than its minimum operating voltage; when Vin+ ≥ V 二级 , a voltage division is provided to the third circuit through the second circuit; when Vin+ ≥ V 三级 , the third circuit directly connects the external power supply to the positive pole of the input end of the discharge circuit based on the voltage division provided by the second circuit; where V 一级 , V 二级 , V 三级 are set voltage values, and V 三级 > V 二级 > V 一级 .

Description

Technical Field

[0001] The present invention relates to the technical field of discharge circuits, and particularly to a discharge device with a pre-connection undervoltage protection function. Background Art

[0002] Modern satellites or spacecrafts are gradually developing towards the trend of having more payloads and higher power. To meet the high-power demand and ensure the high reliability of the aerospace power subsystem, the bus voltage and the battery pack voltage are often increased during design to ensure the maximum power output per unit current. Therefore, high-voltage buses and high-voltage battery packs are gradually applied in aerospace power systems.

[0003] In an aerospace power system, the power controller stores the energy collected by the solar array during the illumination period into the battery pack for discharging the battery during the shadow period. As an important part of the power controller, the aerospace power discharge circuit converts the primary voltage bus into a secondary voltage bus to supply power to the loads of low-voltage power distribution, or converts the high voltage of the battery pack into a low voltage to supply power to the loads. However, directly connecting the high voltage of the primary bus or the battery pack to the discharge circuit has the following two disadvantages: First, when the input voltage is connected instantaneously, it charges the backend capacitor, resulting in an excessive starting surge current, causing stress impact on the devices, and even breaking down the devices in severe cases; Second, during the process of the input voltage rising slowly, the output voltage also rises gradually. If the operating voltage value range of the output load is small, the output low voltage may damage or destroy the load device. Summary of the Invention

[0004] The purpose of the present invention is to provide a discharge device with a pre-connection undervoltage protection function. The first to third circuits of the pre-connection undervoltage protection circuit in the device have a hierarchical startup function, which can gradually connect the output voltage of the pre-connection undervoltage protection circuit to the main power discharge circuit. Through the present invention, the problem that the stress impact on the devices of the main power discharge circuit caused by the excessive starting surge current when the pre-connection undervoltage protection circuit is instantaneously connected to the main power discharge circuit is effectively solved. At the same time, when the output voltage value of the pre-connection undervoltage protection circuit is lower than the set voltage value V 一级 , the pre-connection undervoltage protection circuit and the main power discharge circuit will not establish a connection; effectively avoiding damage to the load device caused by the input voltage of the main power discharge circuit being lower than the minimum voltage value for its safe operation during the process of the output voltage of the pre-connection undervoltage protection circuit rising from 0V.

[0005] To achieve the above purpose, the present invention provides a discharge device with a pre-connection undervoltage protection function, comprising:

[0006] A discharge circuit for supplying power to external devices;

[0007] The pre - connection undervoltage protection circuit supplies power to the discharge circuit based on the electrical energy provided by an external power supply, and includes: a first circuit, a second circuit, and a third circuit; the external power supply is a regulated power supply.

[0008] The input end of the first circuit is connected to the external power supply, and the output end of the first circuit is connected to the positive pole of the input end of the discharge circuit and the input end of the second circuit; the third circuit is connected to the external power supply, the positive pole of the input end of the discharge circuit, and the output end of the second circuit.

[0009] The pre - connection undervoltage protection circuit includes four working states:

[0010] The first working state, Vin+ < V 一级 , the pre - connection undervoltage protection circuit does not supply power to the discharge circuit; Vin+ is the input voltage value of the discharge device, and V 一级 is a set voltage value.

[0011] The second working state, V 一级 ≤Vin+ < V 二级 , the external power supply is connected to the positive pole of the input end of the discharge circuit and the input end of the second circuit through the first circuit, and the input voltage of the discharge circuit is greater than its minimum working voltage; V 二级 is a set voltage value.

[0012] The third working state, V 二级 ≤Vin+ < V 三级 , a voltage division is provided to the third circuit through the second circuit.

[0013] The fourth working state, V 三级 ≤Vin+ < V e , the third circuit directly connects the external power supply to the positive pole of the input end of the discharge circuit based on the voltage division provided by the second circuit; V 三级 is a set voltage value, and V e is the input regulated power supply voltage.

[0014] Optionally, the first circuit includes: a power switch tube Q1, a current - limiting resistor R5, a capacitor C1, and voltage - dividing resistors R1, R2, R3, and R4.

[0015] The source electrode of the power switch tube, the first end of the voltage - dividing resistor R1, and the first end of the capacitor C1 are connected to the external power supply; the second end of the voltage - dividing resistor R1 is connected to the first end of the voltage - dividing resistor R2; the second end of the voltage - dividing resistor R2, the first end of the voltage - dividing resistor R3, the first end of the voltage - dividing resistor R4, the second end of the capacitor C1, and the gate electrode of the power switch tube Q1 are connected to each other; the second end of the voltage - dividing resistor R3 and the second end of the voltage - dividing resistor R4 are grounded; the drain electrode of the power switch tube Q1 is connected to the first end of the current - limiting resistor R5, and the second end of the current - limiting resistor R5 is connected to the positive pole of the input end of the discharge circuit.

[0016] When Vin+≥V 一级 , the power switch Q1 conducts.

[0017] Optionally, the second circuit includes: a voltage regulator diode D1, voltage dividing resistors R6 and R7, a current limiting resistor R8, and a triode Q3;

[0018] The second terminal of the current limiting resistor R5 is connected to the first terminal of the voltage dividing resistor R6; the second terminal of the voltage dividing resistor R6 is connected to the cathode of the voltage regulator diode D1; the anode of the voltage regulator diode D1, the first terminal of the voltage dividing resistor R7, and the first terminal of the current limiting resistor R8 are connected to each other; the second terminal of the voltage dividing resistor R7 and the emitter of the triode Q3 are grounded; the second terminal of the current limiting resistor R8 is connected to the base of the triode Q3; the collector of the triode Q3 is connected to the third circuit;

[0019] When Vin+≥V 二级 , the triode Q3 conducts.

[0020] Optionally, the third circuit includes: a power switch Q2, a capacitor C2, voltage dividing resistors R 10 , R 11 , R 12 , R 13 ;

[0021] The first terminal of the voltage dividing resistor R 10 , the first terminal of the capacitor C2, and the source of the power switch Q2 are connected to an external power supply; the second terminal of the voltage dividing resistor R 10 is connected to the first terminal of the voltage dividing resistor R 11 ; the second terminal of the capacitor C2, the second terminal of the voltage dividing resistor R 11 , the first terminal of the voltage dividing resistor R 12 , the first terminal of the voltage dividing resistor R 13 , and the gate of the power switch Q2 are connected to each other; the second terminal of the voltage dividing resistor R 12 , the second terminal of the voltage dividing resistor R 13 are connected to the collector of the triode Q3; the drain of the power switch Q2 is connected to the second terminal of the current limiting resistor R5;

[0022] When Vin+≥V 三级 , the power switch Q2 conducts.

[0023] Optionally, the discharge circuit includes: a main discharge power circuit and a discharge control circuit;

[0024] The main discharge power circuit includes: power switches Q3 and Q4, capacitors C3, C4, and C5, a transformer T1, diodes D2, D3, and D4, an auxiliary winding L1, and a load resistor R 14 ; The transformer T1 includes: a primary winding L2, a first secondary winding L3, and a second secondary winding L4;

[0025] The source electrode of the power switch tube Q3, the first end of the capacitor C3, the second end of the current-limiting resistor R5, and the drain electrode of the power switch tube Q2 are connected to each other; the drain electrode of the power switch tube Q3 is connected to the first end of the primary winding L2; the source electrode of the power switch tube Q4, the second end of the capacitor C3, and the first end of the capacitor C4 are connected to the second end of the primary winding L2; the drain electrode of the power switch tube Q4 and the second end of the capacitor C4 are grounded;

[0026] The first end of the first secondary winding L3 is connected to the anode of the diode D2, the cathode of the diode D2 is connected to the first end of the auxiliary winding L1, and the second end of the auxiliary winding L1, the anode of the diode D4, and the first end of the capacitor C5 are connected to each other; the cathode of the diode D4 is connected to the first end of the load resistor R 14 ; the second end of the first secondary winding L3, the first end of the second secondary winding L4, the second end of the capacitor C5, and the second end of the load resistor R 14 are grounded; the second end of the second secondary winding L4 is connected to the anode of the diode D3; the cathode of the diode D3 is connected to the first end of the auxiliary winding L1;

[0027] The input end of the discharge control circuit is connected to both ends of the load resistor R 14 ; the output end of the discharge control circuit is connected to the gate electrodes of the power switch tubes Q3 and Q4; the discharge control circuit sends PWM signals to the power switch tubes Q3 and Q4 based on the voltage across the load resistor R 14 across both ends, and controls the conduction and cutoff of the power switch tubes Q3 and Q4.

[0028] Optionally, the pre-connection undervoltage protection circuit further includes a fifth working state, in which Vin+ = V e .

[0029] Optionally, the external power supply is a storage battery.

[0030] Optionally, the number of turns of the first secondary winding L3 is equal to the number of turns of the second secondary winding L4.

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0032] 1) With the increase of the external power supply voltage (the input voltage of the device), the discharge device with the pre-connection undervoltage protection function of the present invention autonomously conducts the power switch tubes in the first to third circuits in sequence, and automatically realizes the hierarchical start function of the first to third circuits; when the first circuit starts, the pre-connection undervoltage protection circuit pre-connects the discharge main power circuit. At this time, the input voltage of the discharge main power circuit is small, and by setting the current-limiting resistor R5, the inrush current of the input discharge main power circuit can be effectively reduced, protecting the components from being damaged.

[0033] 2) When the input voltage value of the pre-connection undervoltage protection circuit of the present invention is lower than the set voltage value V 一级 (undervoltage protection value), the pre-connection undervoltage protection circuit and the discharge main power circuit will not establish a connection; it is ensured that the output voltage of the pre-connection undervoltage protection circuit is greater than the minimum operating voltage of the backend load device (discharge main power circuit), avoiding damage to the components of the backend load device.

[0034] 3) The discharge circuit of the present invention is applicable to the working conditions of high-voltage wide-range input voltage, with a simple circuit and high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solution of the present invention, the drawings required for description will be briefly introduced below. Obviously, the drawings in the following description are an embodiment of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings:

[0036] Figure 1 Schematic diagram of the discharge device with pre-connection undervoltage protection function of the present invention;

[0037] Figure 2 The first circuit schematic diagram of the pre-connection undervoltage protection circuit of the present invention;

[0038] Figure 3 The second circuit schematic diagram of the pre-connection undervoltage protection circuit of the present invention;

[0039] Figure 4 The third circuit schematic diagram of the pre-connection undervoltage protection circuit of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0040] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0041] It should be understood that when used in this specification and the appended claims, the term "comprising" indicates the presence of the described features, wholes, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or their combinations.

[0042] It should also be understood that the terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. As used in the specification of this application and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" are intended to include the plural forms.

[0043] It should be further understood that the term "and / or" used in the specification of this application and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0044] As used in this specification and the appended claims, the term "if" can be interpreted as "when", "once", "in response to determining", or "in response to detecting" depending on the context. Similarly, the phrase "if determined" or "if [the described condition or event] is detected" can be interpreted as meaning "once determined", "in response to determining", "once [the described condition or event] is detected", or "in response to detecting [the described condition or event]" depending on the context.

[0045] In addition, in the description of this application, the terms "first", "second", "third", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0046] The present invention provides a discharge device with a pre-connection undervoltage protection function, as Figure 1 shown, comprising: a discharge circuit 200 and a pre-connection undervoltage protection circuit 100.

[0047] The discharge circuit 200 is used to supply power to an external device.

[0048] The pre-connection undervoltage protection circuit 100 supplies power to the discharge circuit 200 based on the electrical energy provided by an external power source (which is a regulated power source, such as a storage battery). The pre-connection undervoltage protection circuit 100 comprises: a first circuit 101, a second circuit 102, and a third circuit 103.

[0049] As Figure 2 shown, the first circuit 101 comprises: a power switch tube Q1 (which is a PMOS tube in this embodiment), a current-limiting resistor R5, a capacitor C1, and voltage-dividing resistors R1, R2, R3, and R4.

[0050] As Figure 1As shown, the source of the power switch transistor, the first end of the voltage dividing resistor R1, and the first end of the capacitor C1 are connected to an external power supply; the second end of the voltage dividing resistor R1 is connected to the first end of the voltage dividing resistor R2; the second end of the voltage dividing resistor R2, the first end of the voltage dividing resistor R3, the first end of the voltage dividing resistor R4, the second end of the capacitor C1, and the gate of the power switch transistor Q1 are interconnected; the second end of the voltage dividing resistor R3 and the second end of the voltage dividing resistor R4 are grounded; the drain of the power switch transistor Q1 is connected to the first end of the current limiting resistor R5, and the second end of the current limiting resistor R5 is connected to the positive pole of the input end of the discharge circuit.

[0051] As Figure 3 shown, the second circuit 102 includes: a voltage stabilizing diode D1, voltage dividing resistors R6 and R7, a current limiting resistor R8, and a triode Q3.

[0052] As Figure 1 shown, the second end of the current limiting resistor R5 is connected to the first end of the voltage dividing resistor R6; the second end of the voltage dividing resistor R6 is connected to the cathode of the voltage stabilizing diode D1; the anode of the voltage stabilizing diode D1, the first end of the voltage dividing resistor R7, and the first end of the current limiting resistor R8 are interconnected; the second end of the voltage dividing resistor R7 and the emitter of the triode Q3 are grounded; the second end of the current limiting resistor R8 is connected to the base of the triode Q3.

[0053] As Figure 4 shown, the third circuit 103 includes: a power switch transistor Q2 (a PMOS transistor in this embodiment), a capacitor C2, and voltage dividing resistors R 10 、R 11 、R 12 、R 13 .

[0054] As Figure 1 shown, the first end of the voltage dividing resistor R 10 , the first end of the capacitor C2, and the source of the power switch transistor Q2 are connected to an external power supply; the second end of the voltage dividing resistor R 10 is connected to the first end of the voltage dividing resistor R 11 ; the second end of the capacitor C2, the second end of the voltage dividing resistor R 11 , the first end of the voltage dividing resistor R 12 , the first end of the voltage dividing resistor R 13 , and the gate of the power switch transistor Q2 are interconnected; the second end of the voltage dividing resistor R 12 , the second end of the voltage dividing resistor R 13 are connected to the collector of the triode Q3; the drain of the power switch transistor Q2 is connected to the second end of the current limiting resistor R5.

[0055] As Figure 1 shown, the discharge circuit 200 includes: a main discharge power circuit 201 and a discharge control circuit 202.

[0056] The main discharge power circuit 201 includes: power switching transistors Q3 and Q4, capacitors C3, C4, and C5, transformer T1, diodes D2, D3, and D4, auxiliary winding L1, and load resistor R. 14 The transformer T1 includes: primary winding L2, first secondary winding L3, and second secondary winding L4.

[0057] The source of power switching transistor Q3, the first end of capacitor C3, the second end of current-limiting resistor R5, and the drain of power switching transistor Q2 are connected to each other; the drain of power switching transistor Q3 is connected to the first end of primary winding L2; the source of power switching transistor Q4, the second end of capacitor C3, and the first end of capacitor C4 are connected to the second end of primary winding L2; the drain of power switching transistor Q4, the second end of capacitor C4 are grounded.

[0058] The first end of the first secondary winding L3 is connected to the anode of diode D2, the cathode of diode D2 is connected to the first end of auxiliary winding L1, and the second end of auxiliary winding L1, the anode of diode D4, and the first end of capacitor C5 are connected to each other; the cathode of diode D4 is connected to the first end of load resistor R. 14 The second end of the first secondary winding L3, the first end of the second secondary winding L4, the second end of capacitor C5, and the second end of load resistor R 14 are grounded; the second end of the second secondary winding L4 is connected to the anode of diode D3; the cathode of diode D3 is connected to the first end of auxiliary winding L1.

[0059] The turn ratio of the primary winding L2, the first secondary winding L3, and the second secondary winding L4 is N1:N2:N3. In the embodiments of the present invention, N2 is equal to N3.

[0060] The input end of the discharge control circuit 202 is connected to both ends of the load resistor R 14 ; the output end of the discharge control circuit 202 is connected to the gates of power switching transistors Q3 and Q4; the discharge control circuit 202 sends PWM signals to power switching transistors Q3 and Q4 based on the voltage across the load resistor R 14 to control the conduction and cutoff of power switching transistors Q3 and Q4.

[0061] The working principle of the discharge device of the present invention is as follows:

[0062] The pre-connection undervoltage protection circuit 100 includes four working states.

[0063] When the pre-connection undervoltage protection circuit 100 is connected to the external power supply instantaneously, the input voltage Vin+ of the pre-connection undervoltage protection circuit 100 starts to rise from 0V, and the pre-connection undervoltage protection circuit 100 enters the first working state. In the first working state, Vin+ < V 一级 , V 一级is a set voltage value (undervoltage protection value). The voltage-dividing resistors R1, R2, R3, and R4 are used for voltage division. The gate of the power switch Q1 can obtain the voltage division value V2, and the source voltage V1 of the power switch Q1 = Vin+.

[0064]

[0065] The turn-on voltage between the gate and source of the power switch Q1 is V GS1 (which is negative). Before Vin+ rises to the undervoltage protection value V 一级 , |V2 - V1| < |V GS1 |, the power switch Q1 turns off, and the pre-connection undervoltage protection circuit 100 does not supply power to the discharge main power circuit 201. Here, |·| represents taking the absolute value.

[0066] When the input voltage Vin+ reaches the undervoltage protection value V 一级 and continues to rise, the pre-connection undervoltage protection circuit 100 enters the second working state. In the second working state, V 一级 ≤ Vin+ < V 二级 , V 二级 is a set voltage value. When Vin+ ≥ V 一级 , it can satisfy |V2 - V1| ≥ |V GS1 |, the power switch Q1 of the first circuit 101 conducts (also known as the pre-connection undervoltage protection circuit 100 completes the first-stage startup), and the input voltage of the pre-connection undervoltage protection circuit 100 is connected to the discharge main power circuit 201 to achieve the pre-connection function.

[0067] Among them, the current-limiting resistor R5 plays a current-limiting role, limiting the input current Iin of the discharge main power circuit 201 + to:

[0068]

[0069] The voltage drop across the resistor R5 is Iin + ·R5, and the input voltage of the discharge main power circuit 201 is V1 - Iin + ·R5, which is greater than the minimum working voltage when the discharge main power circuit 201 works normally. In the second working state, the duty cycle of the PWM signal is D zkb1 , and the output voltage V0 of the discharge main power circuit 201 (the voltage across the load resistor R 14 ) can be obtained.

[0070]

[0071] Therefore, by setting the undervoltage protection value, the input voltage of the main discharge power circuit 201 can meet its normal working requirements. This effectively solves the problem that during the process of the input voltage of the pre-connection undervoltage protection circuit rising and the output voltage of the pre-connection undervoltage protection circuit 100 rising from 0V to full establishment, the too low output voltage of the pre-connection undervoltage protection circuit 100 causes damage to the backend load device.

[0072] The input voltage Vin+ of the pre-connection undervoltage protection circuit 100 reaches V 二级 and continues to rise, and the pre-connection undervoltage protection circuit 100 enters the third working state. In the third working state, V 二级 ≤Vin+<V 三级 ,V 三级 is the set voltage value. After the first-level startup is completed, the voltage V1-Iin + ·R5 is connected to the main discharge power circuit 201. The on and off of the triode Q3 can be controlled by setting the resistance values of the resistors R6 and R7 and the regulated voltage value V D1 of the voltage regulator diode D1. The turn-on voltage of the triode Q3 is V on ,and the voltage across R7 is V R7 ,then

[0073]

[0074] When Vin+≥V 二级 ,it satisfies V R7 >V on ,and the triode Q3 turns on. At this time, it is also said that the pre-connection undervoltage protection circuit 100 completes the second-level startup, and the second circuit 102 provides voltage division for the third circuit 103.

[0075] The input voltage Vin+ of the pre-connection undervoltage protection circuit 100 reaches V 三级 and continues to rise, and the pre-connection undervoltage protection circuit 100 enters the fourth working state. In the fourth working state, V 三级 ≤Vin+<Ve. Ve is the input regulated power supply voltage. When Vin+ rises, the input voltage V1-Iin + ·R5 of the main discharge power circuit 201 is continuously rising, and the source voltage of the power switch tube Q2 is also continuously rising. When Vin+≥V 三级 ,the source voltage V3 of the power switch tube Q2 has the following relationship:

[0076] V in+ ≥V3>V1-Iin + ·R5

[0077] Through the resistors R 10 、R 11 、R 12 、R 13The voltage is divided, and the gate of the power switch tube Q2 can obtain the divided voltage value V4.

[0078]

[0079] The turn-on voltage between the gate and source of the power switch tube Q2 is V GS2 (which is negative). When Vin+ ≥ V 三级 , |V4 - V3| > |V GS2 |, the power switch tube Q2 conducts (it is also said that the pre-turn-on undervoltage protection circuit 100 completes the three-stage startup). V3 is connected to the discharge main power circuit 201, realizing the second connection of the input voltage of the pre-turn-on undervoltage protection circuit 100 to the discharge main power circuit 201.

[0080] In the fourth working state, the power switch tube Q2 conducts. At this time, V3 is connected to the discharge main power circuit 201, and the duty cycle of the PWM signal is D zkb2 , so the output voltage V0 of the discharge main power circuit 201 can be obtained at this time.

[0081]

[0082] When the power switch tube Q2 conducts, the hierarchical startup function of the pre-turn-on undervoltage protection circuit 100 is completed, and the pre-turn-on undervoltage protection circuit 100 enters the fifth working state. In the fifth working state, the input voltage Vin+ continues to rise to Ve. At this time, the duty cycle of the PWM signal is D zkb3 , so the output voltage V0 of the discharge main power circuit 201 can be obtained at this time.

[0083]

[0084] The bridge arm capacitors C3 and C4 of the discharge main power circuit 201 are periodically charged and discharged alternately through the PWM signal generated by the discharge control circuit 202. By setting the turns ratio of the transformer T1 and rectifying through the diodes D2 and D3, the target output voltage V0 can be obtained, completing the function of input-output voltage conversion. In the discharge control circuit 202, after comparing the collected output voltage V0 and output current I0 of the discharge main power circuit 201 with the reference, through the PI compensation circuit, a PWM signal is generated to control the on and off of the power switch tubes Q3 and Q4, so that the output voltage V0 remains stable (this is the prior art).

[0085] It should be understood that the magnitudes of the sequence numbers of the steps in the above embodiments do not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.

[0086] As described above, it is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of various equivalent modifications or substitutions, and these modifications or substitutions should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A discharge device with a pre-connection undervoltage protection function, characterized in that, Comprising: A discharge circuit for powering an external device; A pre - turn - on undervoltage protection circuit that powers the discharge circuit based on electrical energy provided by an external power supply, comprising: a first circuit, a second circuit, and a third circuit; the external power supply is a regulated power supply; The input terminal of the first circuit is connected to the external power supply, and the output terminal of the first circuit is connected to the positive electrode of the input terminal of the discharge circuit and the input terminal of the second circuit; the third circuit is connected to the external power supply, the positive electrode of the input terminal of the discharge circuit, and the output terminal of the second circuit; The pre - turn - on undervoltage protection circuit has four working states: First working state, Vin+ < V 一级 , the pre-connection undervoltage protection circuit does not supply power to the discharge circuit; Vin+ is the input voltage value of the discharge device, V 一级 is the set voltage value; Second working state, V 一级 ≤Vin + <V 二级 , the external power supply is connected to the positive electrode of the input end of the discharge circuit and the input end of the second circuit through the first circuit, and the input voltage of the discharge circuit is greater than the lowest working voltage of its normal operation; V 二级 is a set voltage value; The third working state, V 二级 ≤Vin + <V 三级 , and provide a voltage division to the third circuit through the second circuit; Fourth working state, V 三级 ≤Vin + <V e , the third circuit realizes the direct connection of the external power supply to the positive electrode of the input end of the discharge circuit based on the voltage division provided by the second circuit; V 三级 is the set voltage value, V e is the input regulated power supply voltage.

2. The discharge device with a pre-connection undervoltage protection function as described in claim 1, characterized in that, The first circuit comprises: a power switch tube Q1, a current - limiting resistor R5, a capacitor C1, voltage - dividing resistors R1, R2, R3, and R4; The source electrode of the power switch tube, the first end of the voltage - dividing resistor R1, and the first end of the capacitor C1 are connected to the external power supply; the second end of the voltage - dividing resistor R1 is connected to the first end of the voltage - dividing resistor R2; the second end of the voltage - dividing resistor R2, the first end of the voltage - dividing resistor R3, the first end of the voltage - dividing resistor R4, the second end of the capacitor C1, and the gate electrode of the power switch tube Q1 are interconnected; the second end of the voltage - dividing resistor R3 and the second end of the voltage - dividing resistor R4 are grounded; the drain electrode of the power switch tube Q1 is connected to the first end of the current - limiting resistor R5, and the second end of the current - limiting resistor R5 is connected to the positive electrode of the input terminal of the discharge circuit; When Vin+ ≥ V 一级 , the power switch Q1 conducts.

3. The discharge device with a pre-connection undervoltage protection function as described in claim 2, wherein The second circuit comprises: a zener diode D1, voltage - dividing resistors R6, R7, a current - limiting resistor R8, and a triode Q3; The second end of the current - limiting resistor R5 is connected to the first end of the voltage - dividing resistor R6; the second end of the voltage - dividing resistor R6 is connected to the cathode of the zener diode D1; the anode of the zener diode D1, the first end of the voltage - dividing resistor R7, and the first end of the current - limiting resistor R8 are interconnected; the second end of the voltage - dividing resistor R7 and the emitter of the triode Q3 are grounded; the second end of the current - limiting resistor R8 is connected to the base of the triode Q3; the collector of the triode Q3 is connected to the third circuit; When Vin+≥V 二级 , the triode Q3 conducts.

4. The discharge device with a pre-connection undervoltage protection function according to claim 3, characterized in that, The third circuit includes: a power switch transistor Q2, a capacitor C2, and voltage-dividing resistors R 10 , R 11 , R 12 , R 13 ; Voltage-dividing resistor R 10 The first terminal of the voltage-dividing resistor R, the first terminal of the capacitor C2, and the source electrode of the power switch tube Q2 are connected to an external power supply; the voltage-dividing resistor R 10 The second terminal of the voltage-dividing resistor R is connected to the first terminal of the voltage-dividing resistor R 11 The second terminal of the capacitor C2, the second terminal of the voltage-dividing resistor R 11 The second terminal of the voltage-dividing resistor R, the first terminal of the voltage-dividing resistor R 12 The first terminal of the voltage-dividing resistor R, the first terminal of the voltage-dividing resistor R 13 The first terminal of the voltage-dividing resistor R, and the gate electrode of the power switch tube Q2 are connected to each other; the voltage-dividing resistor R 12 The second terminal of the voltage-dividing resistor R, the second terminal of the voltage-dividing resistor R 13 The second terminal is connected to the collector of the triode Q3; the drain of the power switch tube Q2 is connected to the second terminal of the current-limiting resistor R5; When Vin+ ≥ V 三级 , the power switch Q2 conducts.

5. The discharge device with a pre-connection undervoltage protection function according to claim 4, characterized in that, The discharge circuit comprises: a discharge main power circuit and a discharge control circuit; The main discharge power circuit includes: power switching transistors Q3 and Q4, capacitors C3, C4, and C5, transformer T1, diodes D2, D3, and D4, auxiliary winding L1, and load resistor R 14 ; The transformer T1 includes: primary winding L2, first secondary winding L3, and second secondary winding L4; The source electrode of the power switch tube Q3, the first end of the capacitor C3, the second end of the current - limiting resistor R5, and the drain electrode of the power switch tube Q2 are interconnected; the drain electrode of the power switch tube Q3 is connected to the first end of the primary winding L2; the source electrode of the power switch tube Q4, the second end of the capacitor C3, and the first end of the capacitor C4 are connected to the second end of the primary winding L2; the drain electrode of the power switch tube Q4 and the second end of the capacitor C4 are grounded; The first end of the first secondary winding L3 is connected to the anode of the diode D2, the cathode of the diode D2 is connected to the first end of the auxiliary winding L1, and the second end of the auxiliary winding L1, the anode of the diode D4, and the first end of the capacitor C5 are interconnected; the cathode of the diode D4 is connected to the first end of the load resistor R 14 ; the second end of the first secondary winding L3, the first end of the second secondary winding L4, the second end of the capacitor C5, and the second end of the load resistor R 14 are grounded; the second end of the second secondary winding L4 is connected to the anode of the diode D3; the cathode of the diode D3 is connected to the first end of the auxiliary winding L1; The input terminal of the discharge control circuit is connected to both ends of the load resistor R 14 ; the output terminal of the discharge control circuit is connected to the gate of the power switch tube Q3 and the gate of the power switch tube Q4; the discharge control circuit sends PWM signals to the power switch tubes Q3 and Q4 based on the voltage across the load resistor R 14 to control the conduction and cutoff of the power switch tubes Q3 and Q4.

6. The discharge device with a pre-connection undervoltage protection function according to claim 5, characterized in that, The pre-connection undervoltage protection circuit further includes a fifth working state, in which Vin+ = V e .

7. The discharge device with a pre-connection undervoltage protection function according to claim 1, characterized in that, The external power supply is a storage battery.

8. The discharge device with a pre-connection undervoltage protection function as claimed in claim 5, characterized in that, The number of turns of the first secondary winding L3 is equal to the number of turns of the second secondary winding L4.

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