Synchronous boost circuit of combined headlight

Abstract

The utility model relates to a combined headlight synchronous boost circuit, a battery is connected with an input energy storage filtering unit, the output of the input energy storage filtering unit is connected with an output energy storage filtering unit through a boost energy storage unit and a control switch MOS tube in a switch control unit in sequence, and the output of the output energy storage filtering unit is connected with a load; the switch control unit comprises a boost control chip U1, a switch MOS tube and a drive circuit of the MOS tube, and the boost control chip U1 receives the voltage difference between the two ends of the boost energy storage unit detected by the detection unit and outputs a control signal to control the switch MOS tube to be connected or disconnected. An original structure that a discrete device field effect transistor MOS is combined with a Schottky diode under a non-synchronous boost circuit is changed into a structure that a discrete device field effect transistor MOS is combined with a field effect transistor MOS under a synchronous boost circuit, so that the working efficiency is improved; in the prior art, in order to meet the same power requirement, multiple paths of asynchronous boost circuits are needed, so that the cost is increased, and the requirement can be met by only one path of synchronous boost circuit.

Description

Technical Field

[0001] The utility model relates to an automobile lighting power supply control technology, in particular to a combined headlight synchronous boost circuit. Background Art

[0002] In the past, automotive lighting had incandescent lamps, halogen lamps, xenon lamps, etc. However, with the continuous expansion of LED in the field of automotive lighting, LEDs are now used in every position of automotive lighting. The gradual rise of LEDs is closely related to its own excellent characteristics. For example, compared with the incandescent lamps used in automotive lighting in the past, LEDs have very significant advantages such as long life, energy saving, high light quality, simple LED structure, good shock resistance, fast response speed, low applicable voltage, small size and the ability to change the shape of the lamp at will.

[0003] Since the headlight assembly has position lights, daytime running lights, turn signals, high beams, low beams, corner lights, and fog lights, the position lights are connected to a control circuit board, the daytime running lights are connected to a control circuit board, the turn signals are connected to a control circuit board, the high beams are connected to a control circuit board, the low beams are connected to a control circuit board, the corner lights are connected to a control circuit board, and the fog lights are connected to a control circuit board. Each control circuit board needs to be connected to the BCM control of the car, and then each circuit board is driven separately to make each light work. Based on such a design, more space needs to be provided on the car to place each control circuit board separately, so that it occupies more space in the car, resulting in increased production costs. Moreover, after the connection, the lines are messy and inconvenient for maintenance.

[0004] Due to the non-integrated drive, its size, weight and power density are not ideal. From split drive units to simple physical integration, it is now moving towards all-in-one intelligent integration and standardized platforms. This direction requires reducing the weight of the system, reducing the size of the system, and effectively improving the power density of the drive system; after the number of parts is reduced, the overall durability of the system is greatly improved, the manufacturing cost is reduced, and it is also more conducive to assembly and production by enterprises. Integration promotes cost reduction and efficiency improvement. Integration can bring advantages such as high efficiency, lightness and low cost. Ultimately, on the one hand, it can simplify the assembly of the whole lamp factory and improve the product qualification rate; on the other hand, it can greatly reduce the number of suppliers to achieve the purpose of standardizing and streamlining the industrial chain.

[0005] Because the asynchronous boost circuit used in the previous integrated boost circuit has low working efficiency and high heat generation, multiple boost circuits are required for power supply, which increases the cost. Utility Model Content

[0006] Aiming at the low working efficiency of non-synchronous boost circuit, a combined headlight synchronous boost circuit is proposed. The synchronous boost circuit is used for optimization. While improving the working efficiency, only one synchronous boost circuit can meet its needs, reducing heat generation and reducing costs.

[0007] The technical solution of the utility model is: a combined headlight synchronous boost circuit, including an input energy storage filter unit, a detection unit, a boost energy storage unit, a switch control unit and an output energy storage filter unit; the battery output is connected to the input energy storage filter unit, the input energy storage filter unit output is connected to the output energy storage filter unit through the boost energy storage unit and the switch control unit in sequence, and the output of the output energy storage filter unit is connected to the load;

[0008] The input energy storage filter unit is a parallel capacitor circuit, which is used to perform energy storage filtering on the positive and negative input terminals of the battery and output stable electric energy;

[0009] The boost energy storage unit is an energy storage device used to store the output electric energy of the input energy storage filter unit;

[0010] The detection unit is a detection device, which is used to detect the voltage values ​​at the input and output ends of the boost energy storage unit and the voltage value at the front end of the output energy storage filter unit, and the detected voltage values ​​are sent to the switch control unit;

[0011] The switch control unit includes a boost control chip U1, two switch MOS tubes and a driving circuit for the two MOS tubes. The boost control chip U1 receives the detection voltage value output by the detection unit and outputs a control signal to control the two switch MOS tubes to be turned on or off; wherein the second switch MOS tube is connected in series between the boost energy storage unit and the ground GND; and the first switch MOS tube is connected in series between the boost energy storage unit and the output energy storage filter unit;

[0012] The output energy storage filter unit is a parallel capacitor circuit, which is used to perform energy storage filtering on the output voltage ripple to supply power to the load.

[0013] Preferably, the detection unit includes an input detection resistor R2 connected between the positive output of the input energy storage filter unit and the boost energy storage unit, a protection circuit to ensure that the voltage difference across the detection resistor R2 changes stably, and an output current limiting resistor R11 connected to the front end of the output energy storage filter unit.

[0014] Preferably, the protection circuit is a resistor R5, a capacitor C10 and a resistor R4 connected in series in sequence, wherein the capacitor C10 is a bypass filter capacitor, and the resistor R5 and the resistor R4 are current limiting resistors.

[0015] Preferably, the first switch MOS tube in the switch control unit is connected in series between the boost energy storage unit and the output energy storage filter unit, the gate of the first switch MOS tube is connected to the boost control chip U1 drive control output end through the current limiting resistor R10 that controls the opening speed of the first switch MOS tube, the gate source of the first switch MOS tube is connected in parallel with the discharge resistor R3 that accelerates the discharge of the gate charge of the first switch MOS tube, and the two ends of the first switch MOS tube are connected to the series resistor R1 and the capacitor C2 for absorbing the noise of the first switch MOS tube.

[0016] Preferably, the second switch MOS tube in the switch control unit is connected in series between the boost energy storage unit and the ground GND, the gate of the second switch MOS tube is connected to the control output end of the boost control chip U1 through a current limiting resistor R8 that controls the opening speed of the second switch MOS tube, the gate source of the second switch MOS tube is connected in parallel with a discharge resistor R7 that speeds up the discharge of the gate charge of the second switch MOS tube, and the two ends of the second switch MOS tube are connected to a series resistor R9 and a capacitor C6 for absorbing the noise of the second switch MOS tube.

[0017] Preferably, the input energy storage filter unit includes an electrolytic capacitor CE1, a capacitor C4, and a capacitor C5, the positive and negative electrodes of the battery being connected in parallel in sequence.

[0018] Preferably, the output energy storage filter unit includes a capacitor C7, a capacitor C8, and an electrolytic capacitor CE2 which are sequentially connected in parallel.

[0019] The beneficial effects of the utility model are as follows: the utility model combined headlight synchronous boost circuit, in view of the problem that the original structure of the discrete device field effect tube MOS combined with the Schottky diode under the asynchronous boost circuit leads to low working efficiency and high heat generation, is changed to a discrete device field effect tube MOS combined with the field effect tube MOS structure under the synchronous boost circuit, thereby improving its working efficiency; in order to achieve the same power requirement, it originally required multiple asynchronous boost circuits, resulting in an increase in its cost, but now only one synchronous boost circuit can meet its demand, thereby reducing its cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a synchronous boost circuit diagram of the combined headlight of the utility model. DETAILED DESCRIPTION

[0021] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and a specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0022] like Figure 1The combined headlight synchronous boost circuit diagram shown includes an input energy storage filter unit, a detection unit, a boost energy storage unit, a switch control unit and an output energy storage filter unit; the positive and negative ends of the battery output stable electric energy after reducing the input voltage ripple through the input energy storage filter unit, and the electric energy is sent to the boost energy storage unit for storage. The detection unit detects the input and output voltages of the boost energy storage unit to determine whether the boost energy storage unit meets the load requirements. The switch control unit receives the detection signal of the detection unit, controls the switch circuit in the switch control unit to turn on or off, and turns on or off the path between the boost energy storage unit and the output energy storage filter unit. The output energy storage filter unit reduces the output voltage ripple and supplies power to the load at the same time.

[0023] The input energy storage filter unit includes an electrolytic capacitor CE1, a capacitor C4, and a capacitor C5, which are connected in parallel in sequence to the positive and negative electrodes of the battery; the detection unit includes an input detection resistor R2 connected between the output positive electrode of the input energy storage filter unit and the inductor L1 of the boost energy storage unit, a protection circuit composed of a resistor R5, a capacitor C10, and a resistor R4 connected in series in sequence, and an output current limiting resistor R11 connected to the front end of the output energy storage filter unit; the switch control unit includes a boost control chip U1, switch MOS tubes Q1, Q2, a driving circuit of the two MOS tubes, and a protection circuit of the two MOS tubes, wherein the switch MOS tube Q1 is connected in series between the inductor L1 of the boost energy storage unit and the ground GND, and the switch MOS tube Q2 is connected in series between the inductor L1 of the boost energy storage unit and the output energy storage filter unit; the output energy storage filter unit includes a capacitor C7, a capacitor C8, and an electrolytic capacitor CE2, which are connected in parallel in sequence.

[0024] 1. Working principle:

[0025] 1. U1 uses MPQ3447U or MPQ3446U, and connects a bootstrap capacitor between the BST and SW pins to provide gate current during the on-time of each cycle to charge the gate of Q1. The VOUT pin of U1 collects the output voltage value through the current limiting resistor R11, and sets the output overvoltage and undervoltage protection values ​​through the internal voltage divider resistor of U1. The CSA pin of U1 and the CSB pin of U1 detect the current ripple of the inductor L1 (the voltage difference across R2) through R2, and set the overpower value to prevent overpower damage.

[0026] 2. When U1 works normally, the current ripple of L1 (the voltage difference across R2) is detected through the CSA pin of U1 and the CSB pin of U1 through R2, and the voltage difference is compared with the value collected by the voltage divider resistor inside the VOUT pin of U1, so as to control the conduction or cutoff of the MOS tube Q2 through the BG pin of U1.

[0027] 3. When the current ripple of L1 (the voltage difference between the two ends of R2) detected by R2 does not reach the set value, the BG pin of U1 outputs a high level and connects to the gate of Q2 through resistor R8, driving Q2 to turn on, L1 is between the positive electrode of the battery and the ground, L1 stores energy, and the TG pin of U1 outputs a low level and connects to the gate of MOS tube Q1 through resistor R10, so that MOS tube Q1 is cut off and disconnected from the load end, and the battery charges the inductor L1 to boost the voltage; the current ripple of L1 (the voltage difference between the two ends of R2) detected by R2 reaches the preset value, and is compared with the value collected by the voltage divider resistor in the VOUT pin of U1. When the two values ​​are equal, The BG pin of U1 outputs a low level to turn off Q2, and the TG pin of U1 outputs a high level to drive Q1 to turn on. The electric energy stored in L1 charges the capacitors C7, C8 and electrolytic capacitor CE2 connected in parallel at the output end of the circuit through the turned-on Q1 and supplies power to the load. At this time, the current ripple on L1 will also decrease. The CSA pin of U1 and the CSB pin of U1 detect the L1 current ripple (the voltage difference across R2) through R2 and decrease. When it decreases to the preset value, the BG pin of U1 outputs a high level to drive Q2 to turn on, and L1 stores energy. At the same time, the TG pin of U1 outputs a low level to turn off Q1, and the above steps are cycled periodically.

[0028] 2. Charging stage during working:

[0029] Current flow: positive pole of power supply BAT+ to R2 to L1 to Q2 to negative pole of power supply BAT-.

[0030] 3. Discharge stage during operation

[0031] Current flow: positive pole of power supply BAT+ to R2 to L1 to Q1 to load to negative pole of power supply BAT-.

[0032] 4. Function of each part:

[0033] CE1, C4, C5 energy storage filter, reduce input voltage ripple; C1, C3 energy storage filter, reduce L1 current ripple to the instantaneous change of voltage difference across R2, increase the stability of the control loop; R5, R4 current limiting, C10 bypass filter, reduce the instantaneous change of voltage difference across R2, increase the stability of the control loop; L1 energy storage filter, boost; C9 bootstrap capacitor, provide Q1 gate current during the conduction period of each cycle, charge the gate of Q1 device; R6 current limiting, reduce C9 discharge current, so as to control the opening of Q1 speed; D1 prevents the leakage current of the BST pin from discharging the voltage of BST-SW to <-0.3V under no-switching conditions; R8 limits the current and controls the opening speed of Q2; R7 discharge resistor accelerates the discharge of Q2 gate charge; Q2 controls the switch; R9 and C6 absorb Q2 noise; R3 discharge resistor accelerates the discharge of Q1 gate charge; R10 limits the current and controls the opening speed of Q1; R1 and C2 absorb Q1 noise; Q1 controls the switch; R11 current limiting resistor; C7, C8, CE2 energy storage filter to reduce output voltage ripple; U1 controller. 4. Key components of synchronous boost topology:

[0034] This is achieved by controlling the on / off of Q1 and Q2 through U1.

[0035] The above-mentioned embodiments only express several implementation methods of the utility model, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the utility model patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the utility model, which all belong to the protection scope of the utility model. Therefore, the protection scope of the utility model patent shall be based on the attached claims.

Claims

1. A combined headlight synchronous boost circuit, characterized in that: It includes an input energy storage filter unit, a detection unit, a boost energy storage unit, a switch control unit and an output energy storage filter unit; the battery output is connected to the input energy storage filter unit, the input energy storage filter unit output is connected to the output energy storage filter unit through the boost energy storage unit and the switch control unit in sequence, and the output of the output energy storage filter unit is connected to the load; The input energy storage filter unit is a parallel capacitor circuit, which is used to perform energy storage filtering on the positive and negative input terminals of the battery and output stable electric energy; The boost energy storage unit is an energy storage device used to store the output electric energy of the input energy storage filter unit; The detection unit is a detection device, which is used to detect the voltage values ​​at the input and output ends of the boost energy storage unit and the voltage value at the front end of the output energy storage filter unit, and the detected voltage values ​​are sent to the switch control unit; The switch control unit includes a boost control chip U1, two switch MOS tubes and a driving circuit for the two MOS tubes. The boost control chip U1 receives the detection voltage value output by the detection unit and outputs a control signal to control the two switch MOS tubes to be turned on or off; wherein the second switch MOS tube is connected in series between the boost energy storage unit and the ground GND; and the first switch MOS tube is connected in series between the boost energy storage unit and the output energy storage filter unit; The output energy storage filter unit is a parallel capacitor circuit, which is used to perform energy storage filtering on the output voltage ripple to supply power to the load.

2. The combined headlight synchronous boost circuit according to claim 1, characterized in that: The detection unit includes an input detection resistor R2 connected between the positive output of the input energy storage filter unit and the boost energy storage unit, a protection circuit to ensure that the voltage difference across the detection resistor R2 changes stably, and an output current limiting resistor R11 connected to the front end of the output energy storage filter unit.

3. The combined headlight synchronous boost circuit according to claim 2, characterized in that: The protection circuit comprises a resistor R5, a capacitor C10 and a resistor R4 which are connected in series in sequence, wherein the capacitor C10 is a bypass filter capacitor, and the resistor R5 and the resistor R4 are current limiting resistors.

4. The combined headlight synchronous boost circuit according to claim 1, characterized in that: The first switch MOS tube in the switch control unit is connected in series between the boost energy storage unit and the output energy storage filter unit. The gate of the first switch MOS tube is connected to the drive control output end of the boost control chip U1 through a current limiting resistor R10 that controls the opening speed of the first switch MOS tube. The gate source of the first switch MOS tube is connected in parallel with a discharge resistor R3 that accelerates the discharge of the gate charge of the first switch MOS tube. The two ends of the first switch MOS tube are connected to a series resistor R1 and a capacitor C2 for absorbing the noise of the first switch MOS tube.

5. The combined headlight synchronous boost circuit according to claim 1, characterized in that: The second switch MOS tube in the switch control unit is connected in series between the boost energy storage unit and the ground GND, the gate of the second switch MOS tube is connected to the control output end of the boost control chip U1 through a current limiting resistor R8 that controls the opening speed of the second switch MOS tube, the gate source of the second switch MOS tube is connected in parallel with a discharge resistor R7 that speeds up the discharge of the gate charge of the second switch MOS tube, and the two ends of the second switch MOS tube are connected to a series resistor R9 and a capacitor C6 for absorbing the noise of the second switch MOS tube.

6. The combined headlight synchronous boost circuit according to claim 1, characterized in that: The input energy storage filter unit includes an electrolytic capacitor CE1, a capacitor C4, and a capacitor C5, the positive and negative electrodes of the battery being connected in parallel in sequence.

7. The combined headlight synchronous boost circuit according to claim 1, characterized in that: The output energy storage filter unit includes a capacitor C7, a capacitor C8, and an electrolytic capacitor CE2 which are sequentially connected in parallel.

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