Car lamp boost control circuit and car lamp controller

Abstract

The invention discloses a vehicle lamp boost control circuit and a vehicle lamp controller, the vehicle lamp boost control circuit comprises a power supply module, an MCU control module and a BOOST module, the power supply module is used for supplying power to the BOOST module, the MCU control module is used for performing SPI communication with the BOOST module to control the BOOST module to stably boost, and the power supply module is used for supplying power to the BOOST module. The BOOST module superposes the output voltage of the first boosting unit and the output voltage of the second boosting unit, so that the output voltage fluctuation of the first boosting unit and the output voltage fluctuation of the second boosting unit are mutually offset, and therefore stable voltage is output. The vehicle lamp boost control circuit performs differential phase control through variable period rectangular waves, respectively drives two independent boost circuits, ensures that stable voltage can be output after superposition of two boost voltages, and can also search and set actual voltage required by a vehicle lamp according to actual requirements of a user, so that the vehicle lamp boost control circuit is more convenient to use. The energy utilization rate is improved; and the electromagnetic radiation interference in the boosting process is reduced.

Description

Technical Field

[0001] The invention belongs to the field of vehicle control, and in particular relates to a vehicle light boost control circuit and a vehicle light controller. Background Art

[0002] At present, light emitting diode (LED) headlights or matrix headlights are commonly used on the market. With the continuous improvement of the requirements for appearance, the shape of headlights has become more and more diverse. Compared with the previous halogen lamps, they are not only more beautiful, but also significantly brighter. However, this has also brought more and more technical difficulties. As we all know, the small battery of a vehicle is generally 12V, but the voltage required to drive a string of LEDs is much greater than 12V, so a boost process is required. Usually, the voltage needs to be increased to more than 40-50V to meet the normal working requirements of the headlights. At present, the voltage is generally fixedly boosted to a specific value on the market, and then the voltage is reduced to drive the headlights. This method has the problem of low energy utilization, and most of the boosting process will generate large electromagnetic radiation interference, which not only affects the electromagnetic compatibility (EMC) performance of the whole vehicle, but may also cause serious interference to the surrounding electrical components. Summary of the invention

[0003] The purpose of the present invention is to provide a headlight boost control circuit and a headlight controller, which perform differential phase control through variable period rectangular waves to drive two independent boost circuits respectively, thereby ensuring that a stable voltage can be output after the two boost voltages are superimposed. At the same time, the actual voltage required for the headlight can be found and set according to the actual needs of the user, thereby solving the technical problems of low energy utilization rate of the boost scheme in the prior art and large electromagnetic radiation interference during the boost process.

[0004] In order to solve the above technical problems, the present invention is achieved through the following technical solutions:

[0005] The present invention provides a vehicle lamp voltage boost control circuit, which comprises: a power supply module, an MCU control module and a BOOST voltage boost module;

[0006] The power supply module is connected to the BOOST boost module and is used to supply power to the BOOST boost module;

[0007] The MCU control module is connected to the BOOST boost module and is used to control the BOOST boost module to stably boost the voltage;

[0008] The BOOST boost module comprises a BOOST chip, a first boost unit, a second boost unit, a first resistor and a second resistor, a power input pin of the BOOST chip is connected to the power module, an input end of the first boost unit is connected to a first output pin of the BOOST chip, an input end of the second boost unit is connected to a second output pin of the BOOST chip, an output end of the first boost unit, an output end of the second boost unit and a first end of the first resistor are connected to each other and then connected to a load, a second end of the first resistor is connected in series with the second resistor and then grounded, and a midpoint of the first resistor and the second resistor is connected to a voltage collection pin of the BOOST chip;

[0009] By superimposing the output voltages of the first boost unit and the second boost unit, output voltage fluctuations of the first boost unit and the second boost unit are offset, thereby outputting a stable voltage.

[0010] In one embodiment of the present invention, the BOOST boost module further includes an input protection unit for preventing reverse connection of the power supply, and the input protection unit includes a first anti-reverse diode, a second anti-reverse diode and an RC filter unit;

[0011] The anode of the first anti-reverse diode is connected to the first output terminal of the power module, and the cathode is connected to the input terminal of the RC filter unit;

[0012] The anode of the second anti-reverse diode is connected to the second output terminal of the power module, and the cathode is connected to the input terminal of the RC filter unit;

[0013] The output end of the RC filter unit is connected to the power input pin of the BOOST chip.

[0014] In one embodiment of the present invention, the first boost unit includes a first inductor, a first switch tube, a first Schottky diode, a first RC absorption unit, a first gate resistor, a first bias resistor, and a first source resistor;

[0015] The first end of the first inductor is connected to the first output end of the power module;

[0016] The second end of the first inductor is connected to the drain of the first switch tube and the anode of the first Schottky diode;

[0017] The cathode of the first Schottky diode is connected to the first end of the first resistor;

[0018] The first RC absorption unit is connected in parallel to the two ends of the first Schottky diode, and is used to absorb transient voltage and realize soft shutdown of the first Schottky diode;

[0019] A first end of the first gate resistor is connected to a first output pin of the BOOST chip, and a second end is connected in series with the first bias resistor and then grounded;

[0020] The gate of the first switch tube is connected to the second end of the first gate resistor, and the source is connected to the first end of the first source resistor;

[0021] A second terminal of the first source resistor is grounded.

[0022] In one embodiment of the present invention, the second boost unit includes a second inductor, a second switch tube, a second Schottky diode, a second RC absorption unit, a second gate resistor, a second bias resistor, and a second source resistor;

[0023] The first end of the second inductor is connected to the second output end of the power module;

[0024] The second end of the second inductor is connected to the drain of the second switch tube and the anode of the second Schottky diode;

[0025] The cathode of the second Schottky diode is connected to the first end of the first resistor;

[0026] The second RC absorption unit is connected in parallel to the two ends of the second Schottky diode, and is used to absorb transient voltage and realize soft shutdown of the second Schottky diode;

[0027] A first end of the second gate resistor is connected to the second output pin of the BOOST chip, and a second end is connected in series with the second bias resistor and then grounded;

[0028] The gate of the second switch tube is connected to the second end of the second gate resistor, and the source is connected to the first end of the second source resistor;

[0029] A second terminal of the second source resistor is grounded.

[0030] In one embodiment of the present invention, the gate control signals of the first switch tube and the second switch tube are pulse width modulation signals, and the first switch tube and the second switch tube are turned on alternately.

[0031] In one embodiment of the present invention, the MCU control module dynamically adjusts the period and duty cycle of the pulse width modulation signal according to the voltage collected by the first voltage collection pin of the BOOST chip to ensure the stability of the output voltage of the BOOST boost module.

[0032] In one embodiment of the present invention, the MCU control module sends different required boost values ​​to the BOOST chip through SPI communication, and the BOOST chip controls the BOOST boost module to perform stable boost according to the written required boost value.

[0033] In one embodiment of the present invention, the BOOST boost module also includes a limp home unit, the input end of the limp home unit is connected to the MCU control module, and the output end is connected to the limp home function input pin of the BOOST chip, and is used for controlling the BOOST chip to perform forced boost output through hard wiring when the SPI communication between the MCU control module and the BOOST chip fails.

[0034] In one embodiment of the present invention, the limp home unit includes a pull-up resistor, a first voltage-dividing resistor, a second voltage-dividing resistor, a filter capacitor and a third switch tube;

[0035] A first end of the pull-up resistor is connected to a limp home function input pin of the BOOST chip, and a second end is connected to an auxiliary power supply;

[0036] A first end of the first voltage-dividing resistor is connected to the limp-home signal output by the MCU control module, and a second end is connected in series with the second voltage-dividing resistor and then grounded;

[0037] The first end of the filter capacitor is connected to the gate of the third switch tube, and the second end is grounded;

[0038] The drain of the third switch tube is connected to the limp home function input pin of the BOOST chip, the gate is connected to the midpoint of the first voltage-dividing resistor and the second voltage-dividing resistor, and the source is grounded.

[0039] Based on the same inventive concept, another embodiment of the present invention further provides a vehicle light controller, the vehicle light controller comprising the vehicle light boost control circuit as described in any of the above embodiments.

[0040] As described above, the present invention provides a vehicle light boost control circuit, comprising a power module, an MCU control module and a BOOST boost module; the power module is connected to the BOOST boost module to supply power to the BOOST boost module; the MCU control module is connected to the BOOST boost module to perform SPI communication with the BOOST boost module to control the BOOST boost module to stably boost; the BOOST boost module comprises a BOOST chip, a first boost unit, a second boost unit, a first resistor and a second resistor, the power input pin of the BOOST chip is connected to the power module, the input pin of the first boost unit The input end is connected to the first output pin of the BOOST chip, the input end of the second boost unit is connected to the second output pin of the BOOST chip, the output end of the first boost unit, the output end of the second boost unit and the first end of the first resistor are connected to each other and then connected to the load, the second end of the first resistor is connected in series with the second resistor and then grounded, and the midpoint of the first resistor and the second resistor is connected to the voltage collection pin of the BOOST chip; wherein, by superimposing the output voltages of the first boost unit and the second boost unit, the output voltage fluctuations of the first boost unit and the second boost unit are offset, thereby outputting a stable voltage. The headlight boost control circuit of the present invention uses a variable period rectangular wave for differential phase control, and drives two boost circuits respectively, ensuring that the two boost voltages can output a stable voltage after being superimposed, greatly reducing voltage fluctuations, and effectively reducing electromagnetic radiation interference caused by voltage glitches or voltage jitters. In addition, the MCU identifies the user's need to turn on the lights, and searches and sets the actual voltage value required for the lights according to the user's actual needs, and then writes the voltage value into the BOOST chip register, thereby achieving on-demand boosting, avoiding unnecessary high-voltage boosting and multiple voltage conversions, greatly improving energy efficiency, and greatly reducing the heat generated by the control module, reducing various faults that may be caused by high temperature, thereby extending the service life of the control module. In addition, the headlight boost control circuit of the present invention adopts two independent power supply systems and independent boost circuits, with double insurance. Even if one of the power supplies fails, the other power supply can still be used normally, thereby ensuring that the headlights can be illuminated safely. In order to minimize electromagnetic radiation emission, the present invention designs RC absorption circuits in both boost circuits. The RC absorption circuit can effectively absorb voltage spikes and realize soft shutdown of Schottky diodes, thereby significantly improving the service life of related components. Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0042] Figure 1 This is a structural block diagram of a vehicle light boost control circuit provided by an exemplary embodiment of the present application.

[0043] Figure 2 A circuit diagram of a vehicle light boost control circuit provided by an exemplary embodiment of the present application.

[0044] Figure 3 A schematic diagram of a rectangular wave for controlling the on and off of a switch tube provided by an exemplary embodiment of the present application.

[0045] Figure 4 A schematic diagram of the first rectangular wave output current and voltage changes when the first switch tube is turned on is provided in an exemplary embodiment of the present application.

[0046] Figure 5 A schematic diagram of the first rectangular wave output current and voltage changes when the first switch tube is turned off provided by an exemplary embodiment of the present application.

[0047] Figure 6 A schematic diagram of the second rectangular wave output current and voltage changes when the first switch tube is turned on is provided in an exemplary embodiment of the present application.

[0048] Figure 7 A schematic diagram of the second rectangular wave output current and voltage changes when the first switch tube is turned off provided by an exemplary embodiment of the present application.

[0049] Figure 8 A schematic diagram of the change of the inductor current and the output voltage under equal-cycle control provided by an exemplary embodiment of the present application.

[0050] Fig. 9 A schematic diagram of a two-path superimposed output voltage with unequal period difference phase provided by an exemplary embodiment of the present application.

[0051] The reference numerals are as follows:

[0052] 100 Power Module

[0053] 200 MCU control module

[0054] 300BOOST boost module

[0055] 310 Input protection unit

[0056] 320 Limp Home Unit

[0057] 330 First booster unit

[0058] 331 first RC absorption unit

[0059] 340 Second booster unit

[0060] 341 Second RC absorption unit

[0061] 350 Output filter unit

[0062] 400 load DETAILED DESCRIPTION

[0063] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0064] It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and thus the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0065] In the following description, numerous details are discussed to provide a more thorough explanation of the embodiments of the present invention. However, it is obvious to those skilled in the art that the embodiments of the present invention can be implemented without these specific details. In other embodiments, well-known structures and devices are shown in the form of block diagrams rather than in detail to avoid making the embodiments of the present invention difficult to understand.

[0066] In order to solve the technical problems of low energy utilization rate of the boosting scheme in the prior art and large electromagnetic radiation interference during the boosting process, the present invention provides a headlight boost control circuit, which performs differential phase control through a variable period rectangular wave to drive two independent boost circuits respectively, ensuring that a stable voltage can be output after the two boost voltages are superimposed. At the same time, it can also find and set the actual voltage required for the headlight according to the actual needs of the user.

[0067] See also Figure 1As shown, in an exemplary embodiment of the present application, the vehicle light boost control circuit includes a power module 100, an MCU control module 200 and a BOOST boost module 300; the power module 100 is connected to the BOOST boost module 300 to supply power to the BOOST boost module 300; the MCU control module 200 is connected to the BOOST boost module 300 to control the BOOST boost module 300 to stably boost; the BOOST boost module 300 includes a BOOST chip, a first boost unit 330, a second boost unit 340, a first resistor R18 and a second resistor R17, the power input pin of the BOOST chip is connected to the power module 100, and the input end of the first boost unit 330 is connected to the BOOST boost module 300. The first boost unit 330 is connected to the first output pin of the BOOST chip, the input end of the second boost unit 340 is connected to the second output pin of the BOOST chip, the output end of the first boost unit 330, the output end of the second boost unit 340 and the first end of the first resistor R18 are connected to each other and then connected to the load, the second end of the first resistor R18 is connected in series with the second resistor R17 and then grounded, and the midpoint of the first resistor R18 and the second resistor R17 is connected to the voltage collection pin of the BOOST chip; wherein, by superimposing the output voltages of the first boost unit 330 and the second boost unit 340, the output voltage fluctuations of the first boost unit 330 and the second boost unit 340 offset each other, thereby outputting a stable voltage.

[0068] It should be noted that, in this embodiment, the power module 100 includes two independent power supply systems, which are specifically used to provide a 12V power supply voltage for the BOOST boost module 300. The BOOST boost module 300 is responsible for receiving the control instructions from the MCU control module 200, and boosting the received power supply voltage to a specified voltage value according to the control instructions. During the boosting process, the BOOST boost module 300 will also feedback the actual output voltage value and whether a fault occurs to the MCU control module 200. The MCU control module 200 communicates with the BOOST boost module 300 through the SPI communication mode, and sends the required boost value, enable signal, and limp home signal to it.

[0069] See also Figure 2As shown, in an exemplary embodiment of the present application, the BOOST boost module 300 also includes an input protection unit 310 for preventing reverse connection of the power supply, and the input protection unit 310 includes a first anti-reverse diode D1, a second anti-reverse diode D2 and an RC filter unit; the anode of the first anti-reverse diode D1 is connected to the first output terminal Vbat1 of the power module 100, and the cathode is connected to the input terminal of the RC filter unit; the anode of the second anti-reverse diode D2 is connected to the second output terminal Vbat2 of the power module, and the cathode is connected to the input terminal of the RC filter unit; the output terminal of the RC filter unit is connected to the power input pin VIN of the BOOST chip.

[0070] The RC filter unit includes a resistor R1 and a capacitor C1. The resistor R1 and the capacitor C1 form a first-order RC low-pass filter for filtering high-frequency noise in the power input and reducing the voltage ripple of the power input, so that the power voltage input is more stable.

[0071] Please continue reading Figure 2 As shown, in an exemplary embodiment of the present application, the first boost unit 330 includes a first inductor L1, a first switch tube Q1, a first Schottky diode D3, a first RC absorption unit, a first gate resistor R22, a first bias resistor R19, and a first source resistor R21; the first end of the first inductor L1 is connected to the first output terminal Vbat1 of the power module 100; the second end of the first inductor L1 is connected to the drain of the first switch tube Q1 and the anode of the first Schottky diode D3; the cathode of the first Schottky diode D3 is connected to the first resistor The first end of R18 is connected; the first RC absorption unit is connected in parallel to the two ends of the first Schottky diode D3, for absorbing transient voltage and realizing soft shutdown of the first Schottky diode D3; the first end of the first gate resistor R22 is connected to the first output pin GATE1 of the BOOST chip, and the second end is connected in series with the first bias resistor R19 and then grounded; the gate of the first switch tube Q1 is connected to the second end of the first gate resistor R22, and the source is connected to the first end of the first source resistor R21; the second end of the first source resistor R21 is grounded.

[0072] The first boost unit 330 further includes a resistor R20 and a capacitor C14, wherein one end of the resistor R20 is connected to the ISP1 pin of the BOOST chip, and the second end is connected to the source of the first switch tube Q1. The first end of the capacitor C14 is connected to the ISP1 pin of the BOOST chip, and the second end is grounded. The BOOST chip uses the ISP1 pin to collect the voltage of the source of the first switch tube Q1, thereby performing voltage detection, and judging whether the first boost unit 330 has a fault.

[0073] The first RC absorption unit includes an absorption capacitor C15 and an absorption resistor R23. The absorption capacitor C15 and the absorption resistor R23 are connected in series and connected to both ends of the first Schottky diode D3, so as to absorb voltage spikes and eliminate oscillations and realize soft shutdown of the first Schottky diode D3, thereby significantly improving the service life of the first Schottky diode D3.

[0074] Please continue reading Figure 2 As shown, in an exemplary embodiment of the present application, the second boost unit 340 includes a second inductor L2, a second switch tube Q2, a second Schottky diode D4, a second RC absorption unit, a second gate resistor R15, a second bias resistor R12, and a second source resistor R13; the first end of the second inductor L2 is connected to the second output terminal Vbat2 of the power module 100; the second end of the second inductor L2 is connected to the drain of the second switch tube Q2 and the anode of the second Schottky diode D4; the cathode of the second Schottky diode D4 is connected to the first resistor The first end of R18 is connected; the second RC absorption unit is connected in parallel to the two ends of the second Schottky diode D4, for absorbing transient voltage and realizing soft shutdown of the second Schottky diode D4; the first end of the second gate resistor R15 is connected to the second output pin GATE2 of the BOOST chip, and the second end is connected in series with the second bias resistor R12 and then grounded; the gate of the second switch tube Q2 is connected to the second end of the second gate resistor R15, and the source is connected to the first end of the second source resistor R13; the second end of the second source resistor R13 is grounded.

[0075] The second boost unit 340 also includes a resistor R14 and a capacitor C4, one end of the resistor R14 is connected to the ISP2 pin of the BOOST chip, and the second end is connected to the source of the second switch tube Q2. The first end of the capacitor C4 is connected to the ISP2 pin of the BOOST chip, and the second end is grounded. The BOOST chip uses the ISP2 pin to collect the voltage of the source of the second switch tube Q2, thereby performing voltage detection, and judging whether the second boost unit 340 has a fault.

[0076] The second RC absorption unit includes an absorption capacitor C6 and an absorption resistor R16. The absorption capacitor C6 and the absorption resistor R16 are connected in series and connected to both ends of the second Schottky diode D4 to absorb voltage spikes and eliminate oscillations and achieve soft shutdown of the second Schottky diode D4, thereby significantly improving the service life of the second Schottky diode D4.

[0077] It should be noted that the gate control signals of the first switch tube Q1 and the second switch tube Q2 are pulse width modulation signals (PWM), and the first switch tube Q1 and the second switch tube Q2 are turned on alternately. The MCU control module 200 dynamically adjusts the period and duty cycle of the pulse width modulation signal according to the voltage collected by the first voltage collection pin FB1 / OV1 of the BOOST chip to ensure the output voltage of the BOOST boost module 300 is stable.

[0078] In an exemplary embodiment of the present application, the MCU control module 300 sends different required boost values ​​to the BOOST chip through SPI communication, and the BOOST chip controls the BOOST boost module 300 to perform stable boost according to the written required boost value.

[0079] Please continue reading Figure 2 As shown, in an exemplary embodiment of the present application, the BOOST boost module 300 also includes a limp home unit 320, the input end of the limp home unit 320 is connected to the MCU control module 200, and the output end is connected to the limp home function input pin LH of the BOOST chip, and is used for controlling the BOOST chip to perform forced boost output through hard wire when the SPI communication between the MCU control module 300 and the BOOST chip fails.

[0080] In an exemplary embodiment of the present application, the limp home unit includes a pull-up resistor R8, a first voltage-dividing resistor R9, a second voltage-dividing resistor R10, a filter capacitor C2 and a third switch tube Q3; the first end of the pull-up resistor R8 is connected to the limp home function input pin LH of the BOOST chip, and the second end is connected to the auxiliary power supply VDD; the first end of the first voltage-dividing resistor R9 is connected to the limp home signal ECU Limp_CON output by the MCU control module, and the second end is connected in series with the second voltage-dividing resistor R10 and then grounded; the first end of the filter capacitor C2 is connected to the gate of the third switch tube Q3, and the second end is grounded; the drain of the third switch tube Q3 is connected to the limp home function input pin LH of the BOOST chip, the gate is connected to the midpoint of the first voltage-dividing resistor R9 and the second voltage-dividing resistor R10, and the source is grounded.

[0081] It should be noted that when the electronic control unit (ECU) detects an internal fault, the third switch tube Q3 is controlled to be turned off, and the LH pin voltage of the BOOST chip is pulled up. When the BOOST chip detects a high level through the LH pin, an independent control system is enabled to force the output of the GATE1 pin and the GATE2 pin. It is worth noting that the BOOST chip and the MCU control module 200 use a serial peripheral interface (SPI) as a communication means. The MOSI pin of the BOOST chip is connected to the MOSI pin of the MCU control module 200 for sending data from the MCU to the BOOST chip. At the same time, the MISO pin of the BOOST chip is connected to the MISO pin of the MCU control module 200 for transmitting data back from the BOOST chip to the MCU.

[0082] Next, we will combine the Figure 3 To Attachment Fig. 9 To elaborate on the working principle of the headlight boost control circuit:

[0083] The vehicle light boost control circuit adopts a two-phase boost control method, specifically, time-sharing control through the GATE1 pin and the GATE2 pin of the BOOST chip, that is, when the GATE1 pin controls the first switch tube Q1 to turn on, the GATE2 pin controls the second switch tube Q2 to turn off. Similarly, when the GATE2 pin controls the second switch tube Q2 to turn on, the GATE1 pin controls the first switch tube Q1 to turn off. It should be noted that, in this embodiment, the first switch tube Q1, the second switch tube Q2 and the third switch tube Q3 are all N-type MOS tubes. Please refer to Figure 3 As shown, the MCU control module 200 controls the staggered on and off of the first switch tube Q1 and the second switch tube Q2 by sending a PWM rectangular wave (duty ratio of 50%, period of 2t1).

[0084] When the GATE1 pin controls the first switch tube Q1 to be turned on, the power supply Vbat1 provided by the power module 100 is divided into two paths after passing through the first inductor L1. One path passes through the first switch tube Q1 and the first source resistor R21 and finally reaches the ground. The current magnitude is I m The other path passes through the first Schottky diode D3, the first resistor R18, the second resistor R17, and finally reaches the ground. Its current is I D When the GATE1 pin controls the first switch tube Q1 to turn off, because the inductor has the characteristic that the current cannot change suddenly, at the moment when the first switch tube Q1 is turned off, the current I flowing through the first inductor L1 is L =I Q +ID will remain unchanged, because the first switch tube Q1 is turned off, and the current flowing through the first switch tube Q1 is substantially zero. The current I L =I Q +I D All the voltage will pass through the first resistor R18 and the second resistor R17 and finally return to the ground. Considering only the voltage boost of the first inductor L1, the voltage at the output end can reach I L ×(R18+R17).

[0085] See also Figure 4 As shown in FIG. 1 , when the BOOST chip controls the first switch tube Q1 to turn on through the GATE1 pin, the first inductor L1 is in the power-on stage. As the conduction time of the inductor increases, the output current will continue to increase until At this time, the voltage value at the output end also reaches the maximum value V out =U bat When the first switch tube Q1 is turned on for a time period of t1, the current of the first inductor L1 is I L1 =I Q1 +I D1 , the output current is I D1 , the output voltage is U out1 =I D1 ×(R17+R18).

[0086] See also Figure 5 As shown, when the BOOST chip controls the first switch tube Q1 to be turned off through the GATE1 pin, since the first inductor L1 has the characteristic that the current cannot change suddenly, that is, the current I flowing through the first inductor L1 L1 =I Q1 +I D1 Will remain unchanged. At this time, the first inductor L1 is in the discharge stage. The current at the inductor end all returns to the ground through the first Schottky diode D3, the first resistor R18, and the second resistor R17. At this time, the voltage U out =U max =I L1 ×(R17+R18), as the inductor continues to discharge, the current and voltage will continue to decrease. When the discharge time reaches t1, the inductor current is I L2 , the output current is V = o ut2 =I L2 ×(R17+R18).

[0087] See also Figure 6 As shown, when the BOOST chip outputs a high level through the GATE1 pin, the first switch tube Q1 is turned on, and the first inductor L1 starts to charge. Because the inductor has the characteristic that the current cannot change suddenly, when the first switch tube Q1 is just turned on, the current of the first inductor L1 is I L2, but the current flowing through the first Schottky diode D3 suddenly changes, and part of the current flows back to the ground through the first switch tube Q1 and the first source resistor R21. That is, the output voltage U out A mutation occurred. As the charging time of the inductor increases, the current flowing through the first inductor L1 increases continuously, and the voltage at the output end also increases continuously. When the charging time reaches t1, the current flowing through the inductor reaches I L3 , the voltage at the output also reaches U out3 .

[0088] See also Figure 7 As shown, when the BOOST chip executes the low level of the second matrix wave through the GATE1 pin, the first switch tube Q1 is immediately turned off. At this time, the first inductor L1 is in a discharge state. Before the first switch tube Q1 is turned off, the current flowing through the first inductor L1 is I L3 , that is, when the first switch tube Q1 is turned off, the current flowing through the first inductor L1 will remain unchanged, that is, it is also I L3 , because the first switch tube Q1 is turned off at this time, the current of the first inductor L1 passes through the first Schottky diode D3, the first resistor R18, the second resistor R17, and finally returns to the ground to form a loop. At this time, the voltage at the output end is U out =U max =I L3 ×(R17+R18).

[0089] According to the above description of the two matrix waves controlling the on and off rules of the switch tubes according to the unchanged period, when a single switch tube is controlled, the changes in the inductor current and the output voltage can be found in Figure 8 As shown in FIG. 1 , the current flowing through the first inductor L1 increases continuously in a sawtooth shape, but the maximum and minimum values ​​tend to be stable. L1 L3 L5 L7 , but the difference between the two adjacent values ​​will continue to decrease and tend to be stable. Because the inductor has the characteristic that the current cannot change suddenly, the output voltage will change suddenly at the moment when the switch tube is turned on and off. For example, in the first rectangular wave cycle, when the switch tube changes from on (the first inductor L1 is charged) to off (the first inductor L1 is discharged), the output voltage changes from U out1 Mutation to I L1 ×(R17+R18).

[0090] ​​​If a single switch tube is used to control the voltage boost, the output voltage jump will be relatively large, which is not conducive to stable voltage output. Moreover, if the rectangular wave period that controls the opening and closing of the switch tube remains unchanged, the output voltage will continue to increase as the output time increases. If a variable rectangular wave period is used for control and the opening and closing time of the switch tube is continuously adjusted, the output voltage can be guaranteed to be basically consistent in each cycle.

[0091] The vehicle lamp boost control circuit of the present invention adopts two-way boost difference phase control, that is, the output voltage is the superposition of the two-way boost voltage, which can avoid the output voltage jumping in a large range and greatly improve the electromagnetic interference (EMI). After adopting two-way difference phase control and variable rectangular wave period control, the output voltage can be guaranteed to be basically constant. Please refer to Fig. 9 As shown, the red line represents the output voltage after the first inductor L1 is boosted, the black line represents the output voltage after the second inductor L2 is boosted, t1 is the first half cycle of the rectangular wave, t2 is the second half cycle of the rectangular wave, t3 is the third half cycle of the rectangular wave, and so on. In the half cycle 0-t1, the first switch tube Q1 is turned on, the first inductor L1 starts to charge, and the output voltage gradually increases from zero. In the half cycle t1-t2, the first switch tube Q1 is turned off, the first inductor L1 starts to discharge, and the output voltage increases from U discharge2 Gradually reduce to U discharge1 At the same time, the second switch tube Q2 is turned on, the second inductor L2 starts to charge, and the output voltage is U charge1 Gradually rise to U charge2 In the half cycle t1-t2, the boosted voltages of the first inductor L1 and the second inductor L2 are superimposed and output. At t1, the boosted output voltage of the first inductor L1 is the maximum, and the boosted output voltage of the second inductor L2 is the minimum. The total output voltage is U discharge2 +U charge1 At time t2, the output voltage of the first inductor L1 is the smallest after boosting, but the output voltage of the second inductor L2 is the largest after boosting. The total output voltage is U discharge1 +U charge2 , the superimposed voltage of the two boosted paths remains basically unchanged in the entire half cycle, that is, U discharge2 +U charge1 ≈U discharge1 +U charge2 .

[0092] Based on the same inventive concept, another embodiment of the present invention further provides a vehicle light controller, the vehicle light controller comprising the vehicle light boost control circuit described in any of the above embodiments. Since the vehicle light controller provided in this embodiment and the vehicle light boost control circuit provided in any of the above embodiments belong to the same inventive concept, they at least have the same beneficial effects as the above embodiments, and are not described one by one here.

[0093] In summary, the present invention provides a vehicle light boost control circuit, comprising a power module, an MCU control module and a BOOST boost module; the power module is connected to the BOOST boost module to supply power to the BOOST boost module; the MCU control module is connected to the BOOST boost module to perform SPI communication with the BOOST boost module to control the BOOST boost module to stably boost; the BOOST boost module comprises a BOOST chip, a first boost unit, a second boost unit, a first resistor and a second resistor, the power input pin of the BOOST chip is connected to the power module, the input pin of the first boost unit is connected to the The input end is connected to the first output pin of the BOOST chip, the input end of the second boost unit is connected to the second output pin of the BOOST chip, the output end of the first boost unit, the output end of the second boost unit and the first end of the first resistor are connected to each other and then connected to the load, the second end of the first resistor is connected in series with the second resistor and then grounded, and the midpoint of the first resistor and the second resistor is connected to the voltage acquisition pin of the BOOST chip; wherein, by superimposing the output voltages of the first boost unit and the second boost unit, the output voltage fluctuations of the first boost unit and the second boost unit are offset, thereby outputting a stable voltage. The headlight boost control circuit of the present invention can flexibly control the rectangular wave cycle to achieve different stable boost values. The MCU sends different required boost values ​​to the BOOST chip through SPI communication according to the customer's demand for turning on the headlights, and the BOOST chip controls different rectangular wave cycles for stable boost according to the written required boost value. For example, if the driver only turns on the position light, the MCU writes the required configured voltage value into the corresponding register of the BOOST chip, and the BOOST chip boosts according to the written required boost value. If the driver turns on the position lights and low beam lights, the MCU will write the larger value of the two configuration values ​​into the corresponding register of the BOOST chip based on the previously configured position light and low beam voltage values, and the BOOST chip will boost the voltage according to the written required boost value. Similarly, if the driver turns on multiple lights at the same time, the MCU will compare the maximum value of the configuration voltage among the turned-on lights, and write the maximum value into the corresponding register of the BOOST chip, and the BOOST chip will boost the voltage according to the written required boost value. Applying this method, it is possible to boost the voltage according to actual needs and avoid excessive boosting, which not only reduces the conversion efficiency, but also causes excessive internal heating and rapid temperature rise, thereby affecting the service life of the control module and reducing energy utilization.

[0094] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A vehicle lamp boost control circuit, characterized in that: include: Power module, MCU control module and BOOST boost module; The power supply module is connected to the BOOST boost module and is used to supply power to the BOOST boost module; The MCU control module is connected to the BOOST boost module and is used to control the BOOST boost module to stably boost the voltage; The BOOST boost module comprises a BOOST chip, a first boost unit, a second boost unit, a first resistor and a second resistor, a power input pin of the BOOST chip is connected to the power module, an input end of the first boost unit is connected to a first output pin of the BOOST chip, an input end of the second boost unit is connected to a second output pin of the BOOST chip, an output end of the first boost unit, an output end of the second boost unit and a first end of the first resistor are connected to each other and then connected to a load, a second end of the first resistor is connected in series with the second resistor and then grounded, and a midpoint of the first resistor and the second resistor is connected to a voltage collection pin of the BOOST chip; By superimposing the output voltages of the first boost unit and the second boost unit, output voltage fluctuations of the first boost unit and the second boost unit are offset, thereby outputting a stable voltage.

2. The vehicle light boost control circuit according to claim 1, characterized in that: The BOOST boost module also includes an input protection unit for preventing reverse connection of the power supply, and the input protection unit includes a first anti-reverse diode, a second anti-reverse diode and an RC filter unit; The anode of the first anti-reverse diode is connected to the first output terminal of the power module, and the cathode is connected to the input terminal of the RC filter unit; The anode of the second anti-reverse diode is connected to the second output terminal of the power module, and the cathode is connected to the input terminal of the RC filter unit; The output end of the RC filter unit is connected to the power input pin of the BOOST chip.

3. The vehicle light boost control circuit according to claim 1, characterized in that: The first boost unit includes a first inductor, a first switch tube, a first Schottky diode, a first RC absorption unit, a first gate resistor, a first bias resistor, and a first source resistor; The first end of the first inductor is connected to the first output end of the power module; The second end of the first inductor is connected to the drain of the first switch tube and the anode of the first Schottky diode; The cathode of the first Schottky diode is connected to the first end of the first resistor; The first RC absorption unit is connected in parallel to the two ends of the first Schottky diode, and is used to absorb transient voltage and realize soft shutdown of the first Schottky diode; A first end of the first gate resistor is connected to a first output pin of the BOOST chip, and a second end is connected in series with the first bias resistor and then grounded; The gate of the first switch tube is connected to the second end of the first gate resistor, and the source is connected to the first end of the first source resistor; A second terminal of the first source resistor is grounded.

4. The vehicle light boost control circuit according to claim 1, characterized in that: The second boost unit includes a second inductor, a second switch tube, a second Schottky diode, a second RC absorption unit, a second gate resistor, a second bias resistor, and a second source resistor; The first end of the second inductor is connected to the second output end of the power module; The second end of the second inductor is connected to the drain of the second switch tube and the anode of the second Schottky diode; The cathode of the second Schottky diode is connected to the first end of the first resistor; The second RC absorption unit is connected in parallel to the two ends of the second Schottky diode, and is used to absorb transient voltage and realize soft shutdown of the second Schottky diode; A first end of the second gate resistor is connected to the second output pin of the BOOST chip, and a second end is connected in series with the second bias resistor and then grounded; The gate of the second switch tube is connected to the second end of the second gate resistor, and the source is connected to the first end of the second source resistor; A second terminal of the second source resistor is grounded.

5. The vehicle lamp boost control circuit according to claims 3 and 4, characterized in that: The gate control signals of the first switch tube and the second switch tube are pulse width modulation signals, and the first switch tube and the second switch tube are turned on alternately.

6. The vehicle lamp boost control circuit according to claim 5, characterized in that: The MCU control module dynamically adjusts the period and duty cycle of the pulse width modulation signal according to the voltage collected by the first voltage collection pin of the BOOST chip to ensure the stability of the output voltage of the BOOST boost module.

7. The vehicle light boost control circuit according to claim 1, characterized in that: The MCU control module sends different required boost values ​​to the BOOST chip through SPI communication, and the BOOST chip controls the BOOST boost module to perform stable boost according to the written required boost value.

8. The vehicle light boost control circuit according to claim 1, characterized in that: The BOOST boost module also includes a limp home unit, the input end of the limp home unit is connected to the MCU control module, and the output end is connected to the limp home function input pin of the BOOST chip, and is used for controlling the BOOST chip to perform forced boost output through hard wiring when the SPI communication between the MCU control module and the BOOST chip fails.

9. The vehicle lamp boost control circuit according to claim 8, characterized in that: The limp home unit includes a pull-up resistor, a first voltage-dividing resistor, a second voltage-dividing resistor, a filter capacitor and a third switch tube; A first end of the pull-up resistor is connected to a limp home function input pin of the BOOST chip, and a second end is connected to an auxiliary power supply; A first end of the first voltage-dividing resistor is connected to the limp-home signal output by the MCU control module, and a second end is connected in series with the second voltage-dividing resistor and then grounded; The first end of the filter capacitor is connected to the gate of the third switch tube, and the second end is grounded; The drain of the third switch tube is connected to the limp home function input pin of the BOOST chip, the gate is connected to the midpoint of the first voltage-dividing resistor and the second voltage-dividing resistor, and the source is grounded.

10. A vehicle light controller, characterized in that: The vehicle light controller comprises a vehicle light boost control circuit as described in any one of claims 1 to 9 above.

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