Low-cost far and near light driving circuit scheme

Abstract

The invention relates to the technical field of vehicle lighting electronic control, and discloses a low-cost high-beam and low-beam driving circuit scheme, which comprises a high-beam signal input circuit comprising a D18, a D4 and an HB I / O, a high-beam control signal of an external high-beam signal input end HB + is received through the D18 and transmitted to the HB I / O, and the signal stability is guaranteed through the D4; the switching circuit comprises a T3, a T5, an R11, an R16 and a VOUT1 which are set to be NPN type triodes, high and low level signals of the HB I / O are transmitted to the T5 through the R11, and voltage division signals of the VOUT1 are transmitted to the T3 through the R16. According to the low-cost high-beam and low-beam driving circuit scheme, the high-beam and low-beam loads are driven at the same time by adopting the switching power supply circuit, so that an additional driving circuit in a traditional scheme is omitted, the number of components required by the circuit and the hardware layout space are greatly reduced, the purchase cost of core hardware is reduced, and the cost of the low-cost high-beam and low-beam driving circuit is reduced. And the production and assembly process is simplified, and the time cost of production and debugging links is reduced.

Description

Technical Field

[0001] This invention relates to the field of vehicle lighting electronic control technology, specifically a low-cost high and low beam drive circuit solution. Background Technology

[0002] The high / low beam drive circuit is an electronic circuit system that controls the switching and stable operation of the vehicle's headlights between high and low beams. Its core function is to receive control signals (mechanical levers, electronic switches, or intelligent sensor signals) to turn the high / low beams on and off, switch modes, and ensure that the lights operate stably under vehicle voltage fluctuations and load changes.

[0003] In existing technologies, separate driving circuits are required for high beams and low beams, doubling the number of components. This not only increases the procurement costs of core hardware but also occupies more hardware layout space. Furthermore, the complex circuit structure prolongs the production and assembly process, increasing the time costs of production and debugging. Moreover, existing high and low beam driving circuits lack reliability and stability, lacking comprehensive anti-reverse, filtering, and voltage regulation designs. They struggle to cope with vehicle voltage fluctuations, high-frequency interference, and voltage spike noise, easily leading to abnormal LED operation and shortening the lifespan of the LEDs and related components. Summary of the Invention

[0004] (a) Technical problems to be solved:

[0005] To address the shortcomings of existing technologies, this invention provides a low-cost high and low beam driving circuit solution, which solves the problems of high cost, insufficient reliability and stability, and short LED lifespan of independent driving circuits mentioned in the background.

[0006] (II) Technical Solution:

[0007] To achieve the above objectives, the present invention provides the following technical solution: a low-cost high / low beam driving circuit solution, comprising:

[0008] The high beam signal input circuit includes D18, D4 and HBI / O. The high beam control signal from the external high beam signal input terminal HB+ is received through D18 and transmitted to HBI / O. The signal stability is ensured by D4.

[0009] The switching circuit includes transistors T3 and T5, R11, R16, and VOUT1, which are configured as NPN transistors. The high and low level signals of the HBI / O are transmitted to T5 through R11, and the voltage divider signal of VOUT1 is transmitted to T3 through R16. By utilizing the conduction / cutoff characteristics of the transistors, T3 and T5 work alternately, thereby controlling the switching between low beam LEDs and high beam LEDs. This allows the high and low beam functions to be realized through a single power supply in conjunction with the high beam signal input circuit and the switching circuit, reducing the cost and space required for configuring separate independent drive circuits.

[0010] Preferably, one end of D18 is connected to HB+, and the other end is connected to HBI / O;

[0011] One end of D4 is connected to HBI / O, and the other end is grounded;

[0012] The switching circuit also includes HB LED+ and LB LED-;

[0013] One end of T3 is connected to the LB LED-, and the other end is connected to VOUT1;

[0014] One end of T5 is connected to HB LED+, and the other end is connected to VOUT1;

[0015] One end of R11 is connected to the HBI / O, and the other end is connected to the T5 control terminal;

[0016] One end of R16 is connected to VOUT1, and the other end is connected to the T3 control terminal.

[0017] Preferably, the high beam signal input circuit further includes:

[0018] D3, one end is connected to HB+, and the other end is connected to the connection node between D18 and HBI / O;

[0019] R27, one end is connected to the HBI / O, and the other end is connected to R11 of the switching circuit;

[0020] R24, one end connected to the HBI / O, the other end grounded;

[0021] C24, one end is connected to the HBI / O, and the other end is grounded.

[0022] Preferably, the switching circuit further includes:

[0023] R18, one end of which is connected to the control terminal of T5, and the other end is grounded;

[0024] C16, one end is connected to VOUT1, and the other end is connected to GND.

[0025] Preferably, the switching circuit further includes:

[0026] TP2, with one end connected to VOUT1 and the other end connected to the connection node between R16 and the control terminal of T3, is used to detect the voltage signal of T3 and verify the working status of T3.

[0027] Preferably, it also includes a filtering circuit, including an input port and an output port, for filtering high-frequency interference and voltage spike noise in the input signal, so that the voltage and current transmitted to subsequent circuits are more stable.

[0028] Preferably, it further includes:

[0029] The anti-reverse circuit includes two signal input terminals and one signal output terminal, which are respectively connected to the external low beam signal input terminal LB+ and the external high beam signal input terminal HB+. The signal output terminal is connected to the input port of the filter circuit, which is used to receive the input signal of the external low beam signal input terminal LB+ and transmit it to the filter circuit after anti-reverse and voltage regulation processing, so as to provide a safe and stable signal source for subsequent circuits.

[0030] Preferably, it further includes:

[0031] The switching power supply circuit has its input terminal connected to the output port of the filter circuit and its output terminal connected to VOUT1 of the switching circuit. It is used to convert, stabilize, and regulate the electrical energy input to the switching power supply circuit, and output a stable voltage and current that meet the load requirements.

[0032] Preferably, it further includes:

[0033] The load circuit includes 12 LEDs, of which 8 are connected in series to form a low beam series group and 4 are connected in series to form a high beam series group.

[0034] Preferably, the positive common terminal of the low beam series group is connected to the LB LED+, and the negative common terminal is connected to the HB LED+;

[0035] The positive common terminal of the high beam series group is connected to the HB LED+, and the negative common terminal is grounded. The switching circuit controls the on / off state of the low beam series group and the high beam series group.

[0036] (III) Beneficial Effects:

[0037] The low-cost high / low beam driving circuit solution provided by this invention has the following beneficial effects:

[0038] 1. This low-cost high and low beam drive circuit solution uses a single switching power supply circuit to drive both the high beam and low beam loads simultaneously, thereby eliminating the need for an additional drive circuit in traditional solutions. This significantly reduces the number of components and hardware layout space required for the circuit, thereby not only reducing the procurement cost of core hardware but also simplifying the production and assembly process and reducing the time cost of production and debugging.

[0039] 2. This low-cost high and low beam driving circuit solution provides a safe, stable and demand-compliant power supply for high and low beam LED loads through reverse connection protection and voltage regulation by the anti-reverse circuit, filtering of high-frequency interference and voltage spike noise by the filter circuit, and the power conversion, voltage regulation and regulation synergistic effect of the switching power supply circuit. This effectively avoids the impact of voltage fluctuations and signal interference on the LED working state, significantly improves the overall reliability and stability of the circuit, and extends the service life of LEDs and related components. Attached Figure Description

[0040] Figure 1 This is a block diagram showing the overall circuit connection of the present invention;

[0041] Figure 2 This is a schematic diagram of the anti-reverse circuit structure of the present invention;

[0042] Figure 3 This is a circuit diagram of the switching power supply of the present invention;

[0043] Figure 4 This is a structural diagram of the high beam signal input circuit of the present invention;

[0044] Figure 5 This is a schematic diagram of the switching circuit structure of the present invention;

[0045] Figure 6 This is a structural diagram of the load circuit of the present invention. Detailed Implementation

[0046] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] Example 1

[0048] refer to Figures 1 to 4 and Figure 6 A low-cost high / low beam driving circuit scheme according to a preferred embodiment of the present invention will be described in detail below: including

[0049] The high beam signal input circuit includes D18, D4, and HBI / O. D18 receives the high beam control signal from the external high beam signal input terminal HB+ and transmits it to HBI / O. D4 ensures signal stability. The unidirectional conductivity of D18 effectively prevents reverse current interference in signal transmission, ensuring the high beam control signal is accurately and losslessly transmitted from HB+ to HBI / O. D4, a Zener diode, clamps the signal voltage at HBI / O within a preset safe range, preventing signal distortion due to voltage fluctuations and providing a reliable signal foundation for accurate triggering of subsequent switching circuits.

[0050] The switching circuit includes transistors T3 and T5, configured as NPN transistors, and resistors R11, R16, and VOUT1. R11 transmits the high and low level signals of the HBI / O circuit to T5, and R16 transmits the voltage divider signal from VOUT1 to T3. Utilizing the transistor's on / off characteristics, T3 and T5 alternate operation, thereby controlling the switching between low beam and high beam LEDs. This allows for high and low beam functionality to be achieved with a single power supply, in conjunction with the high beam signal input circuit and the switching circuit, reducing the cost and space required for separate driver circuits. R11 and R16 are current-limiting resistors, providing appropriate drive current to the control terminals of T5 and T3 to prevent excessive current from burning out the transistors. They also regulate the voltage division to ensure the control signal reaches the transistor's on / off threshold voltage, ensuring accurate triggering of the switching action. The alternating operation of T3 and T5 achieves interlocking control of the high and low beam loads, preventing overload caused by simultaneous high and low beam operation. Furthermore, the single power supply significantly simplifies the circuit structure by enabling function switching.

[0051] The D18 connects to HB+ on one end and HBI / O on the other, thereby shortening the signal transmission path, reducing signal attenuation and interference during transmission, and ensuring that the high beam control signal can respond quickly.

[0052] D4 is connected to HBI / O at one end and grounded at the other end, forming a complete voltage regulation circuit. When the voltage at HBI / O rises abnormally, D4 breaks down and conducts, releasing the excess voltage through the ground terminal. This protects HBI / O and the switching circuit components connected afterward from high voltage damage, improving the overall anti-interference capability and stability of the circuit.

[0053] The switching circuit also includes HB LED+ and LB LED-, where HB LED+ is the positive terminal of the high beam load group and LB LED- is the negative terminal of the low beam load group.

[0054] T3 is connected to LB LED- at one end and VOUT1 at the other end. The conduction and cutoff of T3 control the current loop of the low beam load group.

[0055] T5 is connected to HB LED+ at one end and VOUT1 at the other end. The conduction and cutoff of T5 control the current loop of the high beam load group.

[0056] R11 is connected to the HBI / O on one end and to the control terminal of T5 on the other end, so that the high beam control signal output by the HBI / O can directly act on the control terminal of T5. The current limiting function of R11 can accurately control the current flowing into the base of T5, so that T5 can accurately turn on or off under the action of the control signal, avoiding the problem of unstable operation of the transistor due to abnormal base current.

[0057] One end of R16 is connected to VOUT1, and the other end is connected to the control terminal of T3. VOUT1 is the stable voltage output by the switching power supply circuit. Through the voltage division effect of R16, it provides a continuous and stable bias voltage to the control terminal of T3, thereby ensuring that T3 can remain in the conducting state when there is no high beam signal input, so that the low beam LED can work normally.

[0058] Also includes:

[0059] The reverse beam protection circuit includes two signal input terminals and one signal output terminal. These are connected to the external low beam signal input terminal LB+ and the external high beam signal input terminal HB+, respectively. The signal output terminal is connected to the input port of the filter circuit. It receives the input signal from the external low beam signal input terminal LB+, processes it for reverse beam protection and voltage regulation, and then transmits it to the filter circuit, providing a safe and stable signal source for subsequent circuits. The reverse beam protection circuit adopts a bidirectional reverse beam protection design. It prevents reverse current from flowing into the circuit from the LB+ and HB+ input terminals, avoiding circuit burnout caused by reversed power supply polarity. Simultaneously, it uses internal voltage regulator components to initially regulate the input signal, filtering out some low-frequency voltage fluctuations and ensuring the circuit's power supply safety.

[0060] Also includes:

[0061] The switching power supply circuit has its input terminal connected to the output port of the filter circuit and its output terminal connected to VOUT1 of the switching circuit. It is used to convert, regulate, and adjust the electrical energy input to the switching power supply circuit, and output a stable voltage and current that meet the load requirements.

[0062] Also includes:

[0063] The load circuit includes 12 LEDs (model SWWOCS10A is optional), of which 8 are connected in series to form a low beam series group and 4 are connected in series to form a high beam series group. By connecting them in series, the current of the LEDs in the group is kept consistent, ensuring that the brightness of each LED is uniform and avoiding local over-brightness or dimness caused by uneven current distribution, thus improving the stability of the lighting effect.

[0064] The positive common terminal of the low beam series group is connected to the LB LED+, and the negative common terminal is connected to the HB LED+, thereby realizing the reuse of the power supply interface of the low beam series group, eliminating the need for additional independent nodes and saving layout space.

[0065] The positive common terminal of the high beam series group is connected to the HB LED+, and the negative common terminal is grounded. The switching circuit controls the on / off state of the low beam series group and the high beam series group. By sharing the HB LED+ node with the low beam series group to adapt to single-path power supply logic, the grounding design shortens the current loop, and the switching circuit achieves safe interlocking switching.

[0066] The following is the complete working process and working principle of the above embodiments:

[0067] When the external low beam signal input terminal LB+ is powered on, the signal first enters the reverse connection protection circuit. After reverse connection protection and voltage regulation, it is passed to the filter circuit. The filter circuit filters out high-frequency interference and voltage spike noise in the input signal, making the voltage and current more stable. Subsequently, the stable signal is input to the switching power supply circuit. The switching power supply circuit converts, regulates, and adjusts the electrical energy, outputting a stable voltage and current that meets the load requirements to VOUT1 of the switching circuit. During this process, R16 in the switching circuit transmits the voltage divider signal of VOUT1 to the NPN transistor T3, causing T3 to conduct. Since the high beam signal is not input, R11 does not transmit a valid high or low level signal to T5, so T5 is cut off. However, the low beam load group forms a complete current loop because T3 is conducting, and the low beam LED lights up. When the high beam control signal is input to the external high beam signal input terminal HB+, the high beam signal input circuit receives the signal through D18 and transmits it to HB1 / O. D4 ensures signal stability, and R11 transmits the high and low level signals of HB1 / O to T5, causing T5 to conduct. At the same time, T3 is cut off. The high beam load group in the load circuit forms a complete current loop due to the conduction of T5, and the high beam LED lights up. The entire process relies on a single power supply. Through the coordination of the high beam signal input circuit and the switching circuit, the switching characteristics of the transistor are used to achieve the alternating operation of T3 and T5, thereby controlling the switching between low beam LEDs and high beam LEDs. There is no need to configure separate independent driver circuits. At the same time, the synergistic effect of the reverse protection, filtering, and switching power supply circuits also ensures the reliability and stability of the circuit operation.

[0068] Example 2

[0069] refer to Figures 1 to 2 , Figure 5 The high beam signal input circuit also includes:

[0070] D3 connects to HB+ on one end and to the connection node between D18 and HBI / O on the other end, forming a dual unidirectional conduction protection between D3 and D18. This further enhances the anti-reverse interference capability of the high beam signal transmission. When a reverse voltage appears at the HB+ terminal, D3 and D18 work together to completely block the reverse current, preventing damage to HBI / O and subsequent circuits. At the same time, the presence of D3 can divert some abnormal current, reduce the working pressure on D18, and extend its service life.

[0071] R27 is connected to HBI / O on one end and to R11 of the switching circuit on the other end. R27 is an intermediate connection resistor for signal transmission. It not only limits the current but also further shapes the signal output from HBI / O, making the signal waveform more regular and reducing the impact of signal jitter on the T5 control terminal.

[0072] R24 is connected to HBI / O on one end and grounded on the other. R24 is a pull-down resistor. When there is no high beam signal input at HB+, R24 pulls the voltage at HBI / O to a low level, thereby ensuring that T5 is in a stable cutoff state. This prevents T5 from being mis-turned on due to weak residual signals in the circuit and prevents the high beam LED from being lit up accidentally.

[0073] C24 is connected to HBI / O on one end and grounded on the other. C24 is a filter capacitor. Its charging and discharging characteristics filter out high-frequency noise in the signal at HBI / O, making the high beam control signal smoother and more stable, thereby reducing the impact of high-frequency interference on signal transmission and ensuring that the signal output by HBI / O can accurately reflect the high beam control command.

[0074] The switching circuit also includes:

[0075] R18 is a pull-down resistor for the T5 control terminal. One end of R18 is connected to the T5 control terminal, and the other end is grounded. R18 works in conjunction with R24 to pull the voltage of the T5 control terminal to a low level when there is no high beam signal input, keeping T5 in the off state. This prevents the transistor from becoming unstable due to the control terminal being left floating. At the same time, it can divert excess current from the T5 control terminal, protecting the T5 control transistor and improving its working stability and service life.

[0076] C16 is a filter capacitor connected to VOUT1 on one end and GND on the other. It is used to filter out the high-frequency ripple in the output voltage of VOUT1, making the power supply voltage provided by VOUT1 more stable and reducing the impact of voltage fluctuations on the working state of T3 and T5. At the same time, its charging and discharging characteristics can play a voltage compensation role when the circuit voltage fluctuates instantaneously, ensuring the power supply stability of the switching circuit, and thus ensuring the smoothness and stability of the high beam / low beam switching process.

[0077] The switching circuit also includes:

[0078] TP2, with one end connected to VOUT1 and the other end connected to the connection node between R16 and the control terminal of T3, is used to detect the voltage signal of T3 and verify the working status of T3. As a test point, personnel can directly read the voltage value of the control terminal of T3 through testing tools, and thus quickly determine whether T3 is in a normal conducting or cut-off state.

[0079] It also includes a filtering circuit, including input and output ports, to filter high-frequency interference and voltage spike noise in the input signal, making the voltage and current transmitted to subsequent circuits more stable.

[0080] The following is the complete working process and working principle of the above embodiments:

[0081] Throughout the process, in the switching circuit, R16 transmits the voltage divider signal of VOUT1 to NPN transistor T3, causing T3 to conduct. When the high beam signal is not input, R24 pulls the voltage at HBI / O to a low level, and R18 simultaneously pulls the voltage at the control terminal of T5 to a low level, keeping T5 off. The low beam load group forms a complete current loop due to the conduction of T3, and the eight LEDs in the low beam load group light up. In addition, D3 and D18 in the high beam signal input circuit form a double unidirectional conduction protection. C24 filters out high-frequency noise from the signal at HBI / O, ensuring stable signal transmission. When the high beam control signal is input at the external high beam signal input terminal HB+, the high beam signal input circuit receives the signal through D18 and transmits it to HB1 / O. D4 ensures signal stability. R27 shapes the signal and then transmits the high and low level signals of HB1 / O to T5 via R11, turning on T5 and simultaneously turning off T3. The high beam load group forms a complete current loop due to the conduction of T5, illuminating the four LEDs in the high beam load group. C16 in the switching circuit filters out the high-frequency ripple of the VOUT1 output voltage, ensuring a smooth switching process. TP2 can detect the voltage signal of T3 in real time to verify its operating status. The entire process relies on a single power supply. Through multiple protections in the high beam signal input circuit, noise filtering in the filtering circuit, voltage regulation in the switching power supply circuit, and precise control in the switching circuit, T3 and T5 work alternately, thereby controlling the switching of high and low beam LEDs. No independent drive circuit is required, thus improving the reliability and stability of the circuit operation.

[0082] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A low-cost high / low beam driving circuit solution, characterized in that, include: The high beam signal input circuit includes D18, D4 and HBI / O. The high beam control signal from the external high beam signal input terminal HB+ is received through D18 and transmitted to HBI / O. The signal stability is ensured by D4. The switching circuit includes transistors T3 and T5, R11, R16, and VOUT1, which are configured as NPN transistors. The high and low level signals of the HBI / O are transmitted to T5 through R11, and the voltage divider signal of VOUT1 is transmitted to T3 through R16. By utilizing the conduction / cutoff characteristics of the transistors, T3 and T5 work alternately, thereby controlling the switching between low beam LEDs and high beam LEDs. This allows the high and low beam functions to be realized through a single power supply in conjunction with the high beam signal input circuit and the switching circuit, reducing the cost and space required for configuring separate independent drive circuits.

2. The low-cost high / low beam driving circuit scheme according to claim 1, characterized in that: One end of D18 is connected to HB+, and the other end is connected to HBI / O; One end of D4 is connected to HBI / O, and the other end is grounded; The switching circuit also includes HB LED+ and LB LED-; One end of T3 is connected to the LB LED-, and the other end is connected to VOUT1; One end of T5 is connected to HB LED+, and the other end is connected to VOUT1; One end of R11 is connected to the HBI / O, and the other end is connected to the T5 control terminal; One end of R16 is connected to VOUT1, and the other end is connected to the T3 control terminal.

3. The low-cost high / low beam driving circuit scheme according to claim 1, characterized in that: The high beam signal input circuit also includes: D3, one end is connected to HB+, and the other end is connected to the connection node between D18 and HBI / O; R27, one end is connected to the HBI / O, and the other end is connected to R11 of the switching circuit; R24, one end connected to the HBI / O, the other end grounded; C24, one end is connected to the HBI / O, and the other end is grounded.

4. The low-cost high / low beam driving circuit scheme according to claim 1, characterized in that: The switching circuit further includes: R18, one end of which is connected to the control terminal of T5, and the other end is grounded; C16, one end is connected to VOUT1, and the other end is connected to GND.

5. A low-cost high / low beam driving circuit solution according to claim 1, characterized in that: The switching circuit further includes: TP2, with one end connected to VOUT1 and the other end connected to the connection node between R16 and the control terminal of T3, is used to detect the voltage signal of T3 and verify the working status of T3.

6. A low-cost high / low beam driving circuit scheme according to claim 1, characterized in that, It also includes a filtering circuit, including input and output ports, to filter high-frequency interference and voltage spike noise in the input signal, making the voltage and current transmitted to subsequent circuits more stable.

7. A low-cost high / low beam driving circuit scheme according to claim 6, characterized in that, Also includes: The anti-reverse circuit includes two signal input terminals and one signal output terminal, which are respectively connected to the external low beam signal input terminal LB+ and the external high beam signal input terminal HB+. The signal output terminal is connected to the input port of the filter circuit, which is used to receive the input signal of the external low beam signal input terminal LB+ and transmit it to the filter circuit after anti-reverse and voltage regulation processing, so as to provide a safe and stable signal source for subsequent circuits.

8. A low-cost high / low beam driving circuit scheme according to claim 6, characterized in that: Also includes: The switching power supply circuit has its input terminal connected to the output port of the filter circuit and its output terminal connected to VOUT1 of the switching circuit. It is used to convert, stabilize, and regulate the electrical energy input to the switching power supply circuit, and output a stable voltage and current that meet the load requirements.

9. A low-cost high / low beam driving circuit scheme according to claim 1, characterized in that: Also includes: The load circuit includes 12 LEDs, of which 8 are connected in series to form a low beam series group and 4 are connected in series to form a high beam series group.

10. A low-cost high / low beam driving circuit scheme according to claim 1, characterized in that: The positive common terminal of the low beam series group is connected to the LB LED+, and the negative common terminal is connected to the HB LED+; The positive common terminal of the high beam series group is connected to the HB LED+, and the negative common terminal is grounded. The switching circuit controls the on / off state of the low beam series group and the high beam series group.

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