Voltage adjustment circuit for vehicle lights

Abstract

This invention relates to a voltage adjustment circuit for vehicle lighting fixtures, comprising: a power input unit; a step-down control unit; a feedback adjustment voltage output unit capable of supplying a conduction voltage to the lighting fixture; a current sensing unit capable of outputting judgment data, including a current sensor, a comparator, and a judgment unit; and a processing unit that receives the judgment data and performs calculations. If there is a large voltage difference between the conduction voltage and the feedback adjustment output voltage, the current sensor can generate a large sensing current, causing the preset lighting fixture to be lit. If the conduction voltage and the feedback adjustment output voltage are at the same potential, the preset lighting fixture cannot be turned on and a voltage boost adjustment is required.

Description

[Technical Field]

[0001] The present invention relates to a voltage adjustment circuit for vehicle lamps, particularly the processing unit of the voltage adjustment circuit automatically controls the output of a first conduction voltage, a second conduction voltage, or a third conduction voltage from low to high based on the output data of a current sensor, a comparator, and a judge, so as to conduct lamps with different DC voltage specifications, thereby enabling the voltage adjustment circuit suitable for vehicle lamps to provide a variety of DC voltages. [Previous Technology]

[0002] Note that, generally, automobiles and motorcycles powered by internal combustion engines or motors generate the necessary power for electronic devices in the vehicle body (such as ignition devices, fuel injection computers, batteries, lights of various sizes and charging ports) by rotating the rotor of the generator through the operation of the engine, so as to ensure that the electromechanical system can operate normally.

[0003] Furthermore, the output voltage of automobile and motorcycle generators is alternating current (AC) voltage, but most electronic devices in the vehicle body use direct current (DC) voltage. Therefore, a bridge full-wave rectifier is coupled to the generator output to filter and convert the AC voltage into DC voltage. The voltage specification for automotive lighting is approximately 12V DC voltage, but the maximum AC voltage output by automobile and motorcycle generators is approximately 55V. Therefore, voltage adjustment circuits using AC / DC conversion and DC / DC step-down conversion are necessary to meet the requirements of automotive lighting. If the AC / DC converter or DC / DC step-down converter malfunctions, it may cause damage to automotive lighting or other electronic devices. In addition, conventional voltage adjustment circuits installed in automobiles and motorcycles are mostly only suitable for a single voltage specification and cannot provide power to electronic devices with different DC voltage specifications. The aforementioned shortcomings of conventional voltage adjustment circuits need to be addressed by those in the industry through research and development. [Summary of the Invention]

[0004] Therefore, in view of the above-mentioned problems and deficiencies, the inventor collected relevant information and, after extensive evaluation and consideration, designed and invented this voltage adjustment circuit for vehicle lamps.

[0005] The main objective of this invention is to provide a voltage adjustment circuit for vehicle lighting fixtures, comprising: a power input unit; a step-down control unit; a feedback adjustment voltage output unit capable of supplying a conduction voltage to the lighting fixture; a current sensing unit capable of outputting judgment data, including a current sensor, a comparator, and a judgment unit; and a processing unit that receives the judgment data and performs calculations. If there is a large voltage difference between the conduction voltage and the feedback adjustment output voltage, the current sensor can generate a large sensing current, causing the preset lighting fixture to be lit. If the conduction voltage and the feedback adjustment output voltage are at the same potential, the preset lighting fixture cannot be turned on and voltage boost adjustment is required. Through the above, the processing unit automatically controls the output of a first conduction voltage, a second conduction voltage, or a third conduction voltage from low to high based on the output data of the current sensor, comparator, and judgment unit, to turn on lighting fixtures with different DC voltage specifications, thereby enabling the voltage adjustment circuit suitable for vehicle lighting fixtures to provide multiple DC voltages.

[0006] A secondary objective of the present invention is that the power input unit further includes an isolation transformer at the input end of the AC / DC converter to reduce the AC input voltage and reduce line noise, and the AC / DC converter is composed of a bridge full-wave rectifier.

[0007] Another object of the present invention is that the power input unit and the buck control unit are further coupled with a plurality of bypass capacitors that can perform DC rectification and are connected in parallel.

[0008] Another object of the present invention is that the feedback adjustment voltage output unit includes a low-pass filter and the low-pass filter is composed of a complex number of filter capacitors connected in parallel.

[0009] Another object of the present invention is that a manual adjustment output voltage unit is further coupled between the buck control unit and the feedback adjustment voltage output unit. The manual adjustment output voltage unit includes a first mechanical switch that, when closed, causes the conduction voltage to be superimposed with a first feedback adjustment output voltage, and a second mechanical switch that, when closed, causes the conduction voltage to be superimposed with a second feedback adjustment output voltage. When the manual adjustment output voltage unit is activated, it can be sensed by the buck control unit and the microcontroller unit, and the automatic adjustment output voltage unit can be stopped from outputting.

[0010] Another object of the present invention is that the judgment data of the judgment device includes a sequence clock signal, a sequence data output signal and a chip selection signal.

Implementation Method

[0011] In order to achieve the above-mentioned objectives and effects, the technical means and structure adopted by the present invention are described in detail below with reference to the preferred embodiments of the present invention, so as to facilitate a complete understanding.

[0012] Please refer to Figure 1, which is a voltage adjustment circuit diagram of the vehicle lamp of the present invention. As can be clearly seen from the figure, the voltage adjustment circuit of the present invention mainly includes a power input unit 1, a step-down control unit 2, a feedback adjustment voltage output unit 3, a current sensing unit 4, a processing unit 5, and an automatic adjustment output voltage unit 6. Its main components and features are detailed below:

[0013] The power input unit 1 includes an AC / DC converter 11 that converts AC power into DC power and outputs a high DC voltage.

[0014] The step-down control unit 2 receives the high DC voltage and performs voltage reduction processing, and outputs a low DC voltage.

[0015] The feedback adjustment voltage output unit 3 receives the low DC voltage and performs high-frequency noise filtering, and outputs a conduction voltage Vout that can supply power to a preset lamp (not shown in the figure) according to a feedback adjustment output voltage ADJ_Vout.

[0016] The current sensing unit 4 includes a current sensor RSENSE1 that receives the conduction voltage Vout and compares it with the feedback adjustment output voltage ADJ_Vout, and a comparator 41. The comparator 41 receives whether the current sensor RSENSE1 generates a sensing current (current value is about 0.2~0.3A) and outputs a comparison data. The comparison data is logically judged by a judge 42 based on the reference values ​​of a pair of differential signals (REF+, REF-) and outputs a judgment data.

[0017] The processing unit 5 receives the judgment data and performs calculations. If there is a large voltage difference between the conduction voltage Vout and the feedback adjustment output voltage ADJ_Vout, the current sensor RSENSE1 can generate a large sensing current and light up the preset lamp. If the conduction voltage Vout and the feedback adjustment output voltage ADJ_Vout are at the same potential, the preset lamp cannot be turned on and voltage boost adjustment is required. The voltage boost adjustment is performed by the processing unit 5 controlling the first active switch MQ1 of the automatic adjustment output voltage unit 6 to make the conduction voltage Vout superimposed on the first feedback adjustment output voltage ADJ_Vout1 and light up the preset lamp. If the conduction voltage Vout superimposed on the first feedback adjustment output voltage ADJ_Vout1 cannot light up the preset lamp, the processing unit 5 controls the second active switch MQ2 of the automatic adjustment output voltage unit 6 to make the conduction voltage Vout superimposed on the second feedback adjustment output voltage ADJ_Vout2 and light up the preset lamp.

[0018] The power input unit 1 described above further includes an isolation transformer 12 at the input terminal of the AC / DC converter 11 to step down the AC input voltage (e.g., step down the AC 90V~240V produced by the generator to AC 55V) and reduce line noise, and the AC / DC converter 11 is composed of a bridge full-wave rectifier.

[0019] The power input unit 1 and the step-down control unit 2 are further coupled with a plurality of bypass capacitors 7 that can perform DC rectification and are connected in parallel, and these bypass capacitors 7 refer to capacitors (C7, C8, C9, C10, C11, C12, C13).

[0020] The aforementioned feedback adjustment voltage output unit 3 includes a low-pass filter, which is composed of a complex number of filter capacitors connected in parallel, namely capacitors (C2, C3, C4, C5).

[0021] A manual adjustment output voltage unit 8 is coupled between the aforementioned step-down control unit 2 and the feedback adjustment voltage output unit 3 at the coupling node FB. The manual adjustment output voltage unit 8 includes a first mechanical switch SW1 that, when closed, superimposes the conduction voltage Vout with a first feedback adjustment output voltage ADJ_Vout1, and a second mechanical switch SW2 that, when closed, superimposes the conduction voltage Vout with a second feedback adjustment output voltage ADJ_Vout2. When the manual adjustment output voltage unit 8 is activated, it can be sensed by the pins (Feedback) of the step-down control unit 2 and the microcontroller unit 51, causing the automatic adjustment output voltage unit 6 to stop outputting. This means that when the user knows that the voltage specification of the lamp is higher than 12V DC (e.g., 24V or 48V), by directly operating the manual adjustment output voltage unit 8 to the required voltage specification of the lamp, and omitting the operation of the microcontroller unit 51 controlling the adjustment voltage of the automatic adjustment output voltage unit 6, the voltage adjustment circuit can provide a more stable conduction voltage for the lamp.

[0022] The judgment data of the aforementioned judgment device 42 includes a sequence clock signal (SCK), a sequence data output signal (SDO), and a chip select signal (CS).

[0023] The current sensor RSENSE1 of the current sensing unit 4 is composed of a resistor; and the comparator 41 is composed of an operational amplifier.

[0024] The aforementioned processing unit 5 is composed of a microcontroller 51 (MCU) and a low-dropout regulator 52 (LDO). The low-dropout regulator 52 can step down (e.g., step down from 5V to 3.3V) and regulate the DC power supply. After the voltage is stepped down to 3.3V by the low-dropout regulator 52, it can provide the rated voltage for the integrated circuits (ICs) such as the step-down control unit 2, comparator 41, judge 42 and microcontroller 51, and can make these integrated circuits operate stably and not easily burned out.

[0025] The first active switch MQ1 and the second active switch MQ2 of the above-mentioned automatic adjustment output voltage unit 6 are composed of an N-channel enhancement type metal-oxide-semiconductor field-effect transistor (N-MOSFET), and the N-channel enhancement type metal-oxide-semiconductor field-effect transistor has a Zener diode connected between its source (S) and drain (D) to prevent electrostatic discharge.

[0026] The voltage adjustment circuit of the present invention includes at least three conduction voltage values, wherein the voltage range of the first conduction voltage is between 11.9 and 11.999V; the voltage range of the second conduction voltage is between 23.9 and 23.999V; and the voltage range of the third conduction voltage is between 47.9 and 47.999V. The first conduction voltage is suitable for lighting or warning lights of automobiles and locomotives; while the second and third conduction voltages are suitable for lighting or warning lights of (for example, for forklifts, cranes, excavators, or bulldozers of engineering vehicles).

[0027] All resistors (R1~R15), inductors (L1), and some capacitors (C1, C6, C14, C15, C16, C17) in the diagram of the voltage regulation circuit are matching impedances. MCVV and VIN are external voltage sources that are common to general circuits, so individual components will not be described in detail.

[0028] Regarding the operating principle of how the microcontroller 51 adjusts the conduction voltage of the lamp according to the current sensor RSENSE1, for example: the initial DC voltage value of the conduction voltage Vout located to the left of the current sensor RSENSE1 is 0V; the initial DC voltage value of the feedback adjustment output voltage ADJ_Vout located to the right of the current sensor RSENSE1 is 12V. A larger voltage difference (12V - 0V = 12V) can cause the current sensor RSENSE1 to generate a larger sensing current IA (e.g., greater than 0.25A), and cause the lamp with a preset drive voltage of 12V to be lit; conversely, If there is a small voltage difference between the conduction voltage Vout and the feedback adjustment output voltage ADJ_Vout, the current sensor RSENSE1 will generate a small sensing current IA (e.g., less than 0.2A). When the microcontroller 51 receives the judgment data from the judgment unit 42, if the current sensor RSENSE1 generates a small voltage difference (e.g., less than 0.025V), it means that the conduction voltage Vout (e.g., 11.999V) and the feedback adjustment output voltage ADJ_Vout (e.g., 12V) are at the same potential or have a small voltage difference. The default lamp cannot be lit and voltage boost adjustment is required. The voltage boost adjustment method is as follows: If the driving voltage of the preset lamp is 24V, the feedback adjustment output voltage ADJ_Vout is first set to 12V. When the conduction voltage Vout is 12V, the current sensor RSENSE1 generates a small voltage difference (e.g., less than 0.025V). The processing unit 5 controls the first active switch MQ1 of the automatic adjustment output voltage unit 6 to make the conduction voltage Vout superimposed on the first feedback adjustment output voltage ADJ_Vout1, which can generate a feedback adjustment output voltage ADJ_Vout of 24V and make the preset lamp with a driving voltage of 24V light up. If the preset driving voltage of the lamp is 48V, the feedback adjustment output voltage ADJ_Vout is first set to 24V. When the conduction voltage Vout is 24V, the current sensor RSENSE1 generates a small voltage difference (e.g., less than 0.025V). The processing unit 5 controls the second active switch MQ2 of the automatic adjustment output voltage unit 6 to make the conduction voltage Vout superimposed on the second feedback adjustment output voltage ADJ_Vout2, which can generate a feedback adjustment output voltage ADJ_Vout of 48V and make the preset lamp with a driving voltage of 48V light up.

[0029] The main feature of the present invention is that the processing unit 5 of the voltage adjustment circuit automatically controls the output of a first conduction voltage (e.g., 12V), a second conduction voltage (e.g., 24V), or a third conduction voltage (e.g., 48V) from low to high according to the output data of the current sensor RSENSE1, the comparator 41, and the judge 42, so as to conduct lamps with different DC voltage specifications, thereby enabling the voltage adjustment circuit suitable for vehicle lamps to provide a variety of DC voltages.

[0030] The above is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Therefore, any simple modifications and equivalent structural changes made based on the description and drawings of the present invention should also be included in the patent scope of the present invention and are hereby stated.

[0031] In summary, the voltage adjustment circuit for the vehicle lamps described above in this invention can reliably achieve its function and purpose when in use. Therefore, this invention is indeed a highly practical invention. In order to meet the application requirements for an invention patent, this application is hereby filed in accordance with the law. We hope that the Examination Board will grant this application as soon as possible to protect the inventor's hard work in research and development. If the Examination Board has any questions, please do not hesitate to write to us for guidance. The inventor will do his best to cooperate. We would be very grateful for your help. [Simplified Explanation of the Diagram]

[0032] [Figure 1] is a voltage adjustment circuit diagram of the vehicle lamp of the present invention.

Claims

1. A voltage adjustment circuit for a vehicle lamp, comprising: A power input unit includes an AC / DC converter that converts AC power to DC power and outputs a high DC voltage; a step-down control unit that receives the high DC voltage, performs step-down processing, and outputs a low DC voltage; a feedback-adjusted voltage output unit that receives the low DC voltage, performs high-frequency noise filtering, and outputs a conduction voltage that can power a preset lamp according to a feedback-adjusted output voltage; a current sensing unit including a current sensor that receives the conduction voltage and compares it with the feedback-adjusted output voltage, and a comparator that receives whether the current sensor generates a sense current and outputs comparison data. The comparison data is logically judged by a judge based on a pair of differential signal reference values, and a judgment data is output; and a processing unit that receives the judgment data and performs calculation processing. If there is a large voltage difference between the conduction voltage and the feedback-adjusted output voltage, the current sensor can generate a large sense current and the preset lamp can be lit. If the conduction voltage and the feedback adjustment output voltage are at the same potential, the preset lamp cannot be turned on and a voltage boost adjustment is required. The voltage boost adjustment is achieved by the processing unit controlling the first active switch of the automatic adjustment output voltage unit to make the conduction voltage superimposed on the first feedback adjustment output voltage and thus turn on the preset lamp. If the conduction voltage superimposed on the first feedback adjustment output voltage cannot turn on the preset lamp, then the processing unit controls the second active switch of the automatic adjustment output voltage unit to make the conduction voltage superimposed on the second feedback adjustment output voltage and thus turn on the preset lamp.

2. The voltage regulation circuit for vehicle lighting as described in claim 1, wherein the power input unit further includes an isolation transformer at the input terminal of the AC / DC converter to step down the AC input voltage and reduce line noise, and the AC / DC converter is composed of a bridge full-wave rectifier.

3. The voltage regulation circuit for vehicle lighting as described in claim 1, wherein the power input unit and the step-down control unit are further coupled with a plurality of bypass capacitors that can perform DC rectification and are connected in parallel.

4. The voltage adjustment circuit for a vehicle lamp as described in claim 1, wherein the feedback adjustment voltage output unit includes a low-pass filter and the low-pass filter is composed of a complex number of filter capacitors connected in parallel.

5. The voltage adjustment circuit for a vehicle lamp as described in claim 1, wherein a manual adjustment output voltage unit is further coupled between the buck control unit and the feedback adjustment voltage output unit. The manual adjustment output voltage unit includes a first mechanical switch that, when closed, causes the conduction voltage to be superimposed with a first feedback adjustment output voltage, and a second mechanical switch that, when closed, causes the conduction voltage to be superimposed with a second feedback adjustment output voltage. When the manual adjustment output voltage unit is activated, it can be sensed by the buck control unit and the microcontroller unit, causing the automatic adjustment output voltage unit to stop outputting.

6. The voltage adjustment circuit for vehicle lamps as described in claim 1, wherein the judgment data of the judgment device includes a sequence clock signal, a sequence data output signal, and a chip selection signal.

7. The voltage adjustment circuit for a vehicle lamp as described in claim 1, wherein the current sensor of the current sensing unit is composed of a resistor; and the comparator is composed of an operational amplifier.

8. The voltage regulation circuit for vehicle lamps as described in claim 1, wherein the processing unit comprises a microcontroller and a low-dropout regulator, the low-dropout regulator being capable of stepping down and regulating the DC power supply.

9. The voltage adjustment circuit for a vehicle lamp as claimed in claim 1, wherein the first active switch and the second active switch of the automatic adjustment output voltage unit are composed of an N-channel enhancement mode metal-oxide-semiconductor field-effect transistor, and the N-channel enhancement mode metal-oxide-semiconductor field-effect transistor has a Zener diode connected between its source and drain to prevent electrostatic discharge.

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