LLC circuit in vehicle-mounted charger

Abstract

The utility model provides an LLC circuit in a vehicle-mounted charger. The LLC circuit comprises a switch controller U1, an output transformer T1, a switch tube Q3 and a switch tube Q4. The switch tube Q3 and the switch tube Q4 are N-type MOS (Metal Oxide Semiconductor) tubes; one end of the capacitor C1 is connected with high voltage HV, and the other end is grounded; one end of the resistor R1 is connected with high voltage HV, the other end of the resistor R1 is connected with an input voltage detection end of the switch controller U1, one end of the capacitor C2 and one end of the resistor R2, and the other end of the capacitor C2 and the other end of the resistor R2 are grounded; the soft start discharge end of the switch controller U1 is connected with one end of a resistor R3, the other end of the resistor R3 is connected with one end of a resistor R4 and one end of a capacitor C3, and the other end of the capacitor C3 is grounded; the highest frequency clamping end of the switch controller U1 is grounded through a resistor R5; the timing setting end of the switch controller U1 is grounded through a resistor R6 and a capacitor C4 which are connected in parallel. The utility model has the advantages of complete protection function and large output current, and can meet the charging requirement of a high-capacity vehicle-mounted battery.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of core circuits in vehicle charger, especially a LLC circuit in vehicle charger. BACKGROUND

[0002] Vehicle battery energy loss is large when working, and the service life of vehicle battery will be reduced if not timely power supply or long-term power supply.

[0003] For large-capacity vehicle battery, the power supply period will be longer if charged with small current, which affects the use of vehicle.

[0004] In vehicle charger, LLC circuit (half-bridge resonant circuit) is its core circuit, LLC circuit involves more protection functions and determines the ability of output current; Therefore, the design of LLC circuit is crucial. SUMMARY

[0005] In view of the deficiencies in the prior art, the utility model embodiment provides a LLC circuit in vehicle charger, which has the advantages of perfect protection function and large output current, and can meet the charging needs of large-capacity vehicle battery. To achieve the above technical purpose, the utility model embodiment adopts the technical scheme of:

[0006] The utility model embodiment provides a LLC circuit in vehicle charger, which comprises a switching controller U1, an output transformer T1, a switching tube Q3 and a switching tube Q4; The switching tube Q3 and the switching tube Q4 are N-type MOS tubes;

[0007] One end of capacitor C1 is connected to high voltage HV, and the other end is connected to ground; One end of resistor R1 is connected to high voltage HV, and the other end is connected to the input voltage detection end of switching controller U1, one end of capacitor C2 and one end of resistor R2; The other end of capacitor C2 and the other end of resistor R2 are connected to ground; One end of resistor R3 connected to the soft start discharge end of switching controller U1, one end of resistor R4 and one end of capacitor C3 are connected to the other end of resistor R3; The other end of capacitor C3 is connected to ground; The highest frequency clamping end of switching controller U1 is connected to ground through resistor R5; The timing setting end of switching controller U1 is connected to ground through parallel resistor R6 and capacitor C4; The lowest frequency clamping end of switching controller U1 is connected to the other end of resistor R4 and connected to ground through resistor R7; The feedback end of switching controller U1 is connected to one end of capacitor C5 and one end of resistor R10, and the other end of capacitor C5 is connected to ground; The dead zone width setting end of switching controller U1 is connected to ground through resistor R8; The skip / disable input end of switching controller U1 is connected to the other end of resistor R10 and connected to ground through parallel resistor R9 and capacitor C6;

[0008] The power supply end of the switch controller U1 is connected with the power voltage VCC and one end of the capacitor C13 and one end of the capacitor C11, the other end of the capacitor C13 is connected with the power ground, and the other end of the capacitor C11 is connected with the ground; the bootstrap end of the switch controller U1 is connected with one end of the capacitor C7 and the cathode of the diode D1, and the anode of the diode D1 is connected with the power voltage VCC through the resistor R11;

[0009] The high side switch driving end of the switch controller U1 is connected with the base of the PNP triode Q1 and one end of the resistor R12, the emitter of the PNP triode Q1 is connected with the other end of the resistor R12 and one end of the resistor R13; the other end of the resistor R13 is connected with one end of the resistor R14 and the gate of the switch tube Q3, the drain of the switch tube Q3 is connected with the high voltage HV; the half bridge connection end of the switch controller U1 is connected with the other end of the capacitor C7, the collector of the PNP triode Q1, the other end of the resistor R14, the source of the switch tube Q3 and one end of the inductor L1;

[0010] The low side switch driving end of the switch controller U1 is connected with the base of the PNP triode Q2 and one end of the resistor R15, the emitter of the PNP triode Q2 is connected with the other end of the resistor R15 and one end of the resistor R16; the other end of the resistor R16 is connected with one end of the resistor R17 and the gate of the switch tube Q4, the drain of the switch tube Q4 is connected with one end of the inductor L1; the ground connection end of the switch controller U1 is connected with the collector of the PNP triode Q2, the other end of the resistor R17, the source of the switch tube Q4 and the ground;

[0011] The other end of the inductor L1 is connected with the same end of the primary winding of the output transformer T1, the different end of the primary winding of the output transformer T1 is connected with one end of the capacitor C8 and one end of the capacitor C9; the other end of the capacitor C8 is connected with the high voltage HV, and the other end of the capacitor C9 is connected with the ground;

[0012] One end of the resistor R18 is connected with the different end of the primary winding of the output transformer T1, the other end is connected with one end of the capacitor C10, the other end of the capacitor C10 is connected with one end of the resistor R19, the anode of the diode D5 and the cathode of the diode D4, the other end of the resistor R19 and the anode of the diode D4 are connected with the ground; the cathode of the diode D5 is connected with one end of the resistor R20 and one end of the resistor R21, the other end of the resistor R21 is connected with the ground; the other end of the resistor R20 is connected with the fault detection input end of the switch controller U1 and one end of the capacitor C12 and one end of the capacitor C12; the other end of the resistor R22 and the other end of the capacitor C12 are connected with the ground.

[0013] Further, the switch controller U1 adopts NCP1397.

[0014] Further, the LLC circuit in the vehicle charger further comprises the diode D2 and the diode D3; the anode of the diode D2 is connected with one end of the capacitor C8, and the cathode is connected with the high voltage HV; the cathode of the diode D3 is connected with one end of the capacitor C9, and the anode is connected with the ground.

[0015] Further, the secondary of the output transformer T1 is provided with a plurality of secondary windings, the same name ends of the plurality of secondary windings are connected, and the different name ends are connected.

[0016] Further, the secondary windings of the output transformer T1 are configured as 3.

[0017] The beneficial effects brought by the technical scheme provided by the embodiment of the utility model are:

[0018] 1) It has overvoltage and undervoltage protection function, and realizes overcurrent detection and protection function, and the protection function is relatively perfect.

[0019] 2) The output current is large, and the charging needs of the large-capacity vehicle-mounted battery can be met. DRAWINGS

[0020] Figure 1 The LLC circuit principle diagram in the embodiment of the utility model. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical scheme and advantages of the utility model more clear and obvious, the utility model is further described in detail below by combining with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the utility model, and are not used to limit the utility model.

[0022] As shown in Figure 1 The utility model embodiment proposes a LLC circuit in vehicle-mounted charger, including switch controller U1, output transformer T1, switch tube Q3 and switch tube Q4;Switch tube Q3 and switch tube Q4 are N type MOS tube;

[0023] One end of the capacitor C1 is connected to the high voltage HV, and the other end is connected to the ground; one end of the resistor R1 is connected to the high voltage HV, and the other end is connected to the input voltage detection end (5th pin) of the switch controller U1, and one end of the capacitor C2 and one end of the resistor R2, and the other end of the capacitor C2 and the other end of the resistor R2 are connected to the ground; the soft start discharge end (1st pin) of the switch controller U1 is connected to one end of the resistor R3, and the other end of the resistor R3 is connected to one end of the resistor R4 and one end of the capacitor C3, and the other end of the capacitor C3 is connected to the ground; the highest frequency clamping end (2nd pin) of the switch controller U1 is connected to the ground through the resistor R5; the timing setting end (3rd pin) of the switch controller U1 is connected to the ground through the parallel connection of the resistor R6 and the capacitor C4; the lowest frequency clamping end (4th pin) of the switch controller U1 is connected to the other end of the resistor R4 and connected to the ground through the resistor R7; the feedback end (6th pin) of the switch controller U1 is connected to one end of the capacitor C5 and one end of the resistor R10, and the other end of the capacitor C5 is connected to the ground; the dead zone width setting end (7th pin) of the switch controller U1 is connected to the ground through the resistor R8; the skip / disable input end (8th pin) of the switch controller U1 is connected to the other end of the resistor R10 and connected to the ground through the parallel connection of the resistor R9 and the capacitor C6;

[0024] The power supply end (12th pin) of the switch controller U1 is connected to the power supply voltage VCC and one end of the capacitor C13 and one end of the capacitor C11, and the other end of the capacitor C13 is connected to the power supply ground, and the other end of the capacitor C11 is connected to the ground; the bootstrap end (16th pin) of the switch controller U1 is connected to one end of the capacitor C7 and the cathode of the diode D1, and the anode of the diode D1 is connected to the power supply voltage VCC through the resistor R11;

[0025] The high-side switch drive end (15th pin) of the switch controller U1 is connected to the base of the PNP transistor Q1 and one end of the resistor R12, and the emitter of the PNP transistor Q1 is connected to the other end of the resistor R12 and one end of the resistor R13; the other end of the resistor R13 is connected to one end of the resistor R14 and the gate of the switch tube Q3, and the drain of the switch tube Q3 is connected to the high voltage HV; the half-bridge connection end (14th pin) of the switch controller U1 is connected to the other end of the capacitor C7, the collector of the PNP transistor Q1, the other end of the resistor R14, the source of the switch tube Q3, and one end of the inductor L1;

[0026] The low-side switch drive end (11th pin) of the switch controller U1 is connected to the base of the PNP transistor Q2 and one end of the resistor R15, and the emitter of the PNP transistor Q2 is connected to the other end of the resistor R15 and one end of the resistor R16; the other end of the resistor R16 is connected to one end of the resistor R17 and the gate of the switch tube Q4, and the drain of the switch tube Q4 is connected to one end of the inductor L1; the ground end (10th pin) of the switch controller U1 is connected to the collector of the PNP transistor Q2, the other end of the resistor R17, the source of the switch tube Q4, and the ground;

[0027] The other end of the inductor L1 is connected to the same end of the primary winding of the output transformer T1, and the different end of the primary winding of the output transformer T1 is connected to one end of the capacitor C8 and one end of the capacitor C9; the other end of the capacitor C8 is connected to high voltage HV, and the other end of the capacitor C9 is connected to ground;

[0028] One end of the resistor R18 is connected to the different end of the primary winding of the output transformer T1, and the other end of the resistor R18 is connected to one end of the capacitor C10, the anode of the diode D5 and the cathode of the diode D4, and the other end of the resistor R19 and the anode of the diode D4 are connected to ground; the cathode of the diode D5 is connected to one end of the resistor R20 and one end of the resistor R21, and the other end of the resistor R21 is connected to ground; the other end of the resistor R20 is connected to the fault detection input end (the 9th pin) of the switch controller U1 and one end of the resistor R22 and one end of the capacitor C12; the other end of the resistor R22 and the other end of the capacitor C12 are connected to ground.

[0029] In the embodiment, the switch controller U1 is NCP1397; the high voltage HV is output by the circuit before the LLC circuit, about 400v; the detection voltage obtained by voltage division of the resistors R1 and R2 is used for detecting the input voltage, that is, the high voltage HV, and the switch controller U1 is latched to be closed when overvoltage or undervoltage occurs; the current detection signal obtained by rectifying the resonance current of the primary winding of the output transformer T1 by the diodes D4 and D5 is fed back to the fault detection input end (the 9th pin) of the switch controller U1, so as to realize the overcurrent protection function; the capacitors C8 and C9 are resonance capacitors. The output voltage after rectification of the secondary winding of the output transformer T1 can be sampled by an optical coupler and fed back to the feedback end (the 6th pin) of the switch controller U1.

[0030] More preferably, the LLC circuit in the vehicle charger further comprises the diode D2 and the diode D3; the anode of the diode D2 is connected to one end of the capacitor C8, and the cathode is connected to high voltage HV; the cathode of the diode D3 is connected to one end of the capacitor C9, and the anode is connected to ground; the diode D2 and the diode D3 can prevent the voltage on the resonance capacitors C8 and C9 from being too high.

[0031] More preferably, the secondary winding of the output transformer T1 is provided with a plurality of secondary windings, and the same ends of the plurality of secondary windings are connected to each other, and the different ends of the plurality of secondary windings are connected to each other; so that a large current output can be obtained. In the embodiment, the secondary windings are configured as three.

[0032] Finally, it should be explained that the above specific embodiments are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described in detail with reference to the embodiments, it should be understood by those skilled in the art that the technical solutions of the present application can be modified or replaced equivalently without departing from the spirit and scope of the technical solutions of the present application, and all should be covered in the scope of the claims of the present application.

Claims

1. An LLC circuit in an on-board charger, characterized by, The switch controller U1, the output transformer T1, the switch tube Q3 and the switch tube Q4 are included; the switch tube Q3 and the switch tube Q4 are N-type MOS tubes; One end of the capacitor C1 is connected to the high voltage HV, and the other end is connected to the ground; one end of the resistor R1 is connected to the high voltage HV, and the other end is connected to the input voltage detection end of the switch controller U1, and one end of the capacitor C2 and one end of the resistor R2; the other end of the capacitor C2 and the other end of the resistor R2 are connected to the ground; one end of the resistor R3 connected to the soft start discharge end of the switch controller U1, the other end of the resistor R3 is connected to one end of the resistor R4 and one end of the capacitor C3, the other end of the capacitor C3 is connected to the ground; the highest frequency clamping end of the switch controller U1 is connected to the ground through the resistor R5; the timing setting end of the switch controller U1 is connected to the ground through the parallel resistor R6 and the capacitor C4; the lowest frequency clamping end of the switch controller U1 is connected to the other end of the resistor R4 and connected to the ground through the resistor R7; the feedback end of the switch controller U1 is connected to one end of the capacitor C5 and one end of the resistor R10, and the other end of the capacitor C5 is connected to the ground; the dead zone width setting end of the switch controller U1 is connected to the ground through the resistor R8; the skip / disable input end of the switch controller U1 is connected to the other end of the resistor R10 and connected to the ground through the parallel resistor R9 and the capacitor C6; The power supply end of the switch controller U1 is connected to the power supply voltage VCC and one end of the capacitor C13 and one end of the capacitor C11, the other end of the capacitor C13 is connected to the power supply ground, and the other end of the capacitor C11 is connected to the ground; the bootstrap end of the switch controller U1 is connected to one end of the capacitor C7 and the cathode of the diode D1, and the anode of the diode D1 is connected to the power supply voltage VCC through the resistor R11; The high side switch drive end of the switch controller U1 is connected to the base of the PNP triode Q1 and one end of the resistor R12, and the emitter of the PNP triode Q1 is connected to the other end of the resistor R12 and one end of the resistor R13; the other end of the resistor R13 is connected to one end of the resistor R14 and the gate of the switch tube Q3, and the drain of the switch tube Q3 is connected to the high voltage HV; the half-bridge connection end of the switch controller U1 is connected to the other end of the capacitor C7, the collector of the PNP triode Q1, the other end of the resistor R14, the source of the switch tube Q3 and one end of the inductor L1; The low side switch drive end of the switch controller U1 is connected to the base of the PNP triode Q2 and one end of the resistor R15, and the emitter of the PNP triode Q2 is connected to the other end of the resistor R15 and one end of the resistor R16; the other end of the resistor R16 is connected to one end of the resistor R17 and the gate of the switch tube Q4, and the drain of the switch tube Q4 is connected to one end of the inductor L1; the ground end of the switch controller U1 is connected to the collector of the PNP triode Q2, the other end of the resistor R17, the source of the switch tube Q4 and the ground; The other end of the inductor L1 is connected to the same end of the primary winding of the output transformer T1, and the different end of the primary winding of the output transformer T1 is connected to one end of the capacitor C8 and one end of the capacitor C9; the other end of the capacitor C8 is connected to the high voltage HV, and the other end of the capacitor C9 is connected to the ground; One end of the resistor R18 is connected to the opposite end of the primary winding of the output transformer T1, the other end of the resistor R18 is connected to one end of the capacitor C10, the other end of the capacitor C10 is connected to one end of the resistor R19, the anode of the diode D5 and the cathode of the diode D4, the other end of the resistor R19 and the anode of the diode D4 are grounded; the cathode of the diode D5 is connected to one end of the resistor R20 and one end of the resistor R21, the other end of the resistor R21 is grounded; the other end of the resistor R20 is connected to the fault detection input of the switch controller U1 and one end of the resistor R22 and one end of the capacitor C12; the other end of the resistor R22 and the other end of the capacitor C12 are grounded.

2. The LLC circuit in the vehicle charger according to claim 1, wherein, The switch controller U1 is NCP1397.

3. The LLC circuit in the vehicle charger according to claim 1, wherein, The LLC circuit in the vehicle charger further comprises a diode D2 and a diode D3; the anode of the diode D2 is connected to one end of the capacitor C8, the cathode is connected to the high voltage HV; the cathode of the diode D3 is connected to one end of the capacitor C9, the anode is grounded.

4. The LLC circuit in the vehicle charger according to claim 1, wherein, The secondary winding of the output transformer T1 is provided with a plurality of secondary windings, the same end of the plurality of secondary windings is connected, and the opposite end is connected.

5. The LLC circuit in the vehicle charger according to claim 4, wherein, The secondary windings of the output transformer T1 are configured as three.

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