KR20070047476A - Vehicle head lamp control apparatus - Google Patents

Abstract

The present invention provides a headlight control apparatus for a vehicle for preventing shortening of life while maintaining the illuminance of the vehicle headlight in an optimal state.

To this end, the present invention controls the operation of the headlight driving means by dividing the input voltage into a plurality of stages by the headlight driving means for supplying a constant DC voltage to the headlamp by the step-up and decompression operation according to the change of the input voltage. And step-up / depressor control means for controlling the input voltage to be stepped up and down by the headlamp driving means by comparing the voltage signal discrimination means and the measurement signal of the voltage applied to the headlamp and the reference signal.

Vehicle, headlight, illuminance, sawtooth wave, clamping

Description

Vehicle headlight control device {VEHICLE HEAD LAMP CONTROL APPARATUS}

1 is a view showing a circuit configuration for a headlight control apparatus for a vehicle according to the present invention;

2A to 2F are diagrams showing a circuit operation state for controlling input power by dividing the input power into four steps according to a preferred embodiment of the present invention;

3 is a diagram illustrating an operating state of a transistor represented by four stages of input power according to the present invention.

<Description of the symbols for the main parts of the drawings>

2: headlight driving circuit, 10: clamping circuit,

20,30: comparison circuit, 40: reference voltage source circuit,

50: voltage measuring circuit, 60: sawtooth wave generating circuit.

The present invention relates to a headlight control apparatus for a vehicle, and more particularly, to a headlight control apparatus for a vehicle for preventing the shortening of life by maintaining the optimum illuminance for the headlight of the vehicle.

In general, the lighting device of the vehicle includes a headlight, a taillight, a vehicle width lamp, a fog lamp, and the like, most of which are used in the case of a headlight, it is important to maintain a constant illuminance and to prevent shortening of life.

The headlights of these vehicles use the electric load as the battery voltage due to a lack of alternator capacity when a large number of electric loads are used in the vehicle or at a low engine RPM, and the brightness of the headlights due to the voltage drop of the power supply is reduced. There is a possibility that a drop may occur, and in particular, when an electric load consuming a large current is required, three to ten times as much power as the rated power is required. As the fork is generated, the life of the headlamp is expected to be shortened.

On the other hand, as a way to prevent the shortening of the life of the headlamp, there is a method of lowering the high voltage by adjusting the W / H length. In this method, the W / H length and thickness are made longer than necessary to fit the vehicle environment. It is possible to lower the supply voltage of the headlamp by the voltage drop generated, which has the advantage of lowering the supply voltage due to the voltage drop even when the cost is the lowest and the high voltage is supplied. There is a high possibility that the headlights are darker because the same voltage drop occurs, and the headlights become considerably dark, especially when the voltage drop generated from the wire is severe.

In addition, as a method of preventing the shortening of the life of the headlamp, there is a method of reducing the headlight life by lowering the high voltage by using a PWM (Chopping) signal. In this method, even if a high voltage is supplied, the headlight is supplied to the headlamp by the PWM control. It is possible to keep the power constant, so that it is possible to maintain constant power at relatively low cost, but there is no effect in the state where low voltage is supplied, and the brightness of the headlamp decreases due to the voltage drop depending on the number of contact points in the circuit. In addition, the halogen lamp used as a headlamp can reduce the filament temperature of the bulb due to the switching interruption of the power supply, thereby causing an interruption in the halogen cycle process. The disadvantage is that it can be requested.

In addition, there is a method of preventing the shortening of the lifespan of the headlights, and there is a method of maintaining the headlight illuminance and shortening the headlight lifespan by using an electrostatic source holding device. This method uses a PWM control and a transformer to always maintain a constant voltage. By configuring the power supply to maintain the supply of DC output voltage through the headlights. This has the advantage that the headlamp can be maintained in an optimal state by supplying a constant DC voltage regardless of voltage fluctuations, but the cost increase due to the addition of a transformer is inevitable, and due to the mechanical characteristics of the transformer, a noise such as "beep" during operation This has the disadvantage that will occur.

On the other hand, as another method of preventing the shortening of the lifespan of the headlamp, there is a method of configuring a static electricity source holding device using a relay, a boost circuit, and a chopping circuit. When a high voltage is applied, the voltage is lowered by chopping the power supply to charge the capacitor, and when the low voltage is applied, the power is boosted through the boost circuit to increase the voltage. In this case, it is possible to supply a constant DC voltage irrespective of voltage fluctuations, but when the voltage is lowered, a large amount of ripple voltage is generated, and a momentary voltage drop may occur during relay switching. As a result, since both the boost and the step-down circuits are separately configured, the cost increases.

Accordingly, the present invention has been made in view of the above-described conventional situation, and an object thereof is to provide a headlight control apparatus for a vehicle for preventing shortening of life while maintaining the illuminance of the vehicle headlight in an optimal state.

Another object of the present invention is to provide a headlight control device for a vehicle that can reduce the cost and improve the power quality by configuring a circuit for boosting and stepping down the input voltage in a single circuit for supplying a constant DC voltage to the headlight of the vehicle at all times. will be.

Still another object of the present invention is to provide a headlight control apparatus for a vehicle that can contribute to improving durability of the headlight by controlling input power supplied to the vehicle headlight in a plurality of stages.

In order to achieve the above object, according to the present invention, the headlight driving means for supplying a constant DC voltage to the headlamp by the step-up, decompression operation according to the change in the input voltage, and the input voltage is divided into a plurality of stages for each voltage step A voltage step dividing means for controlling the operation of the headlight driving means, and a step-up / decompression control means for controlling the headlamp driving means to step up or down the input voltage by comparing the measurement signal of the voltage applied to the headlamp with a reference signal; It provides a headlight control device for a vehicle, characterized in that configured.

Hereinafter, the present invention configured as described above will be described in detail with reference to the accompanying drawings.

That is, FIG. 1 is a diagram illustrating a circuit configuration of a headlight control apparatus for a vehicle according to the present invention.

As shown in FIG. 1, the headlight control apparatus for a vehicle according to the present invention includes a headlight driving circuit 2 for driving a headlight HL flashing by receiving an input voltage and dividing the supply voltage into four stages, respectively. The clamping circuit 10, the first and second comparison circuits 20 and 30, the reference voltage source circuit 40, the voltage measuring circuit 50 for measuring the voltage supplied to the headlamp HL, a sawtooth wave of a constant frequency It consists of a sawtooth wave generation circuit 60 for making a.

The headlamp driving circuit 2 includes a first transistor Q1 connected in series with one end of the inductor L1, a second transistor Q2 connected in parallel with the inductor L1, diodes D1 and D2, and Two capacitors CE1 and CE2 connected in parallel to the other ends of the inductor l1 are configured.

The first transistor Q1 is driven by a fourth transistor Q4 driven by the first comparison circuit 20, and the second transistor Q2 is driven by the second comparison circuit 30. It is operated by the third transistor Q3.

The clamping circuit 10 includes a zener diode ZD3 connected between an input voltage VB terminal and a ground side, and a diode D3 connected in parallel between the zener diode ZD3 and a resistor R23 on the ground side. It is configured by.

The first comparison circuit 20 has an inverting input terminal (-) connected to an input voltage VB terminal through a resistor R26, and a non-inverting input terminal (+) connected to a reference voltage source circuit through resistors R34 and R35. Comprising a comparator (COMP2) is connected to the 40 is configured.

The second comparison circuit 30 has an inverting input terminal (-) connected to an input voltage VB terminal through a resistor R39 and a non-inverting input terminal (+) connected to the reference voltage source circuit 40. It comprises a comparator COMP4.

The reference voltage source circuit 40 includes a resistor R32 for generating a reference voltage, a zener diode ZD4, and a capacitor C6.

The voltage measuring circuit 50 has its inverting input terminal (-) connected to the power input terminal of the headlamp HL through a resistor R2, and its non-inverting input terminal (+) through a resistor R9. ZD1) and capacitor C1, in addition to the sawtooth wave generating circuit 60, and comprises an amplifier (OP1) for comparing the power supply voltage supplied to the headlight with the sawtooth wave, which changes the bias voltage In addition, inverted amplification of the amplifier OP1 is performed.

The sawtooth wave generating circuit 60 differentiates the output of the comparator COMP3 for oscillation of a predetermined frequency, the plurality of resistors R24, R28, R29, R31, R33, capacitor C5, and the output of the comparator COMP3 The eighth transistor Q8 and the capacitor C4 for discharging the charging voltage of the capacitor C3 and the sixth transistor Q6 for generating the sawtooth wave by the current charging method at the rising edge of the capacitor C3. ), A capacitor C3, and a Zener diode ZD2.

In addition, in the present invention, the inverting input terminal (-) is connected with the sawtooth wave generating circuit 60, and the non-inverting input terminal (+) is connected with the voltage measuring circuit 50, so that the first and second transistors ( A comparator COMP1 for outputting signals for controlling Q1 and Q2 is configured.

The comparator COMP1 compares the output signal from the voltage measuring circuit 50 with the sawtooth signal from the sawtooth wave generating circuit 60 to generate a signal having a required duty value, and thus the signal has a constant hysteresis. And a PWM signal for driving the third and fourth transistors Q3 and Q4.

In the present invention according to the drawing, when the input voltage VB is input at 9 V or less, the comparator COMP2 of the first comparison circuit 20 causes the input voltage VB to be inputted from the reference voltage source circuit 40. As a result of the comparison with the reference voltage, as the output signal of the "high" level is generated, as the seventh transistor Q7 is turned on and the fourth transistor Q4 is turned off, the first transistor Q1 is turned on. It is turned off to cut off the power input to the headlamp (HL).

On the other hand, when the input voltage VB is input at 21 V or more, the "high" level signal through the diode D3 while the zener diode ZD3 of the clamping circuit 10 passes the input voltage VB of 21 V or more. As the seventh transistor Q7 is turned on to turn off the fourth transistor Q4, the first transistor Q1 is turned off to cut off the power input to the headlamp HL.

In addition, when the input voltage VB is input at 9 to 14 V, the zener diode ZD3 of the cranking circuit 10 is turned on by a voltage of 21 V or more, so that the state is maintained in the off state, and thus the "low" level. Outputs a signal, and the comparator COMP2 of the first comparison circuit 20 compares an input voltage VB of 9 to 14V with a reference voltage from the reference voltage source circuit 40 to output a low signal. As is generated, power is supplied to the inductor L1 by turning on the first transistor Q1 by turning on the fourth transistor Q4 while the seventh transistor Q7 is turned off.

At this time, the comparator COMP1 compares the output signal from the voltage measuring circuit 50 with the sawtooth signal from the sawtooth wave generating circuit 60 to obtain a PWM signal capable of determining the current charging time of the inductor L1. To generate a third transistor Q3 and to switch on / off the second transistor Q2 according to the switching of the third transistor Q3 to convert energy from the inductor L1 into the capacitors CE1 and CE2. ) To repeat the charging process to increase the voltage.

When the input voltage VB is input at 14 to 21 V, the comparator COMP4 of the second comparison circuit 30 compares the input voltage VB with a reference voltage from the reference voltage source circuit 40. As the "low" level signal is generated, as the ninth transistor Q9 of the npn transistor is turned on, the third transistor Q3 is turned on to turn off the second transistor Q2 to stop the boost function.

On the other hand, the comparator COMP1 compares the output signal from the voltage measuring circuit 50 and the sawtooth signal from the sawtooth wave generating circuit 60 to obtain a PWM signal capable of determining the current charging time of the inductor L1. To generate the fifth transistor Q5 and to switch on / off the first transistor Q1 according to the switching of the fifth transistor Q5 to convert energy from the inductor L1 into the capacitors CE1 and CE2. ) To repeat the charging process so that the voltage is stepped down.

Here, in the present invention, the input voltage of the headlamp driving circuit 2 is measured to perform the operation divided into four steps. First, when the input voltage VB is input at 9V or less, the first voltage as described above is used. By the operation of the comparison circuit 20, the first transistor Q1 is turned off to cut off the power supply.

In addition, when the input voltage VB is supplied at 9 to 14 V, the input power is boosted by the boost circuit operation so that the rated DC voltage is supplied to the headlamp HL. When the PWM signal is applied and switched to the second transistor Q2 in the turned-on state, a power path of "A" is formed when the second transistor Q2 is turned on, as shown in FIG. 2A, thereby inductor L1. ) Energy is accumulated.

Then, when the second transistor Q2 is turned off by the duty of the PWM signal, the energy of the inductor L1 is charged to the capacitors CE1 and CE2 through the diode D1, as shown in FIG. 2B. As the power path of the "B" is formed as described above, by increasing the amount of energy supplied to the energy consumed by the load, it is possible to increase the voltage up to the breakdown voltage of the capacitors CE1 and CE2.

Meanwhile, according to the signal comparison between the output signal of the voltage measuring circuit 50 by the comparator COMP1 and the sawtooth wave signal of the sawtooth wave generating circuit 60, the voltages of the capacitors CE1 and CE2 are compared with the second voltage. As the duty value of the PWM signal applied to (Q2) is adjusted, as shown in FIG. 2C, the PWM signal of "C" applied to the second transistor Q2 is adjusted.

In addition, when the input voltage VB is input at 14 to 21 V, the input power is reduced by using a buck circuit operation so that the rated DC voltage can be supplied to the headlamp HL. As the PWM signal is applied and switched to the first transistor Q1 while the second transistor Q2 is turned off, as shown in FIG. 2D, when the first transistor Q1 is turned on, the power of "D" is turned on. A path is formed to accumulate energy in the inductor L1, and to charge energy in each of the capacitors CE1 and CE2.

Next, in a state where the first transistor Q1 is turned off by the duty of the PWM signal, as the energy charged in the capacitors CE1 and CE2 performs freewheeling through the diode D2 to form a path, FIG. As shown in 2e, a power path of "E" is formed to allow the voltage to be reduced.

Meanwhile, according to the signal comparison between the output signal of the voltage measuring circuit 50 by the comparator COMP1 and the sawtooth signal of the sawtooth wave generating circuit 60, the voltages of the capacitors CE1 and CE2 are compared with the reference voltages. As the duty value of the PWM signal applied to (Q1) is adjusted, as shown in FIG. 2F, the PWM signal of "F" applied to the first transistor Q1 is adjusted.

In addition, when the input voltage VB is input to 21 V or more, the power is turned off by turning off the first transistor Q1 to cut off the power supply to the headlamp HL in order to protect the capacitors CE1 and CE2. As shown in FIG. 3, the headlamp HL is not turned off substantially since the voltage region of 21 V has a very short occurrence time as a surge voltage form.

On the other hand, the present invention is not limited to the above-described typical preferred embodiments, but can be carried out in various ways without departing from the gist of the present invention, various modifications, alterations, substitutions or additions are common in the art Those who have knowledge will easily understand. If the implementation by such improvement, change, replacement or addition falls within the scope of the appended claims, the technical idea should also be regarded as belonging to the present invention.

According to the present invention as described above, by configuring a circuit for boosting and depressurizing the input voltage into a single circuit so that a constant DC voltage can always be supplied to the headlamp, the headlamp constant illumination irrespective of fluctuations in the power environment. In addition to maintaining it, the disturbance caused by the surge voltage can be eliminated, and the life of the headlamp can be extended, and it is possible to perform a more stable flicker function of the headlamp.

Claims (9)

Headlight driving means for supplying a constant DC voltage to the headlamp by a step-up / decompression operation according to a change in the input voltage; A voltage step dividing means for dividing an input voltage into a plurality of steps to control an operation of the headlamp driving means for each voltage step; A booster / depressor control means for controlling the input voltage of the headlight driving means to increase or decrease the input voltage by comparing the measurement signal of the voltage applied to the headlight and the reference signal. The method of claim 1, The headlamp driving means includes an inductor, a first transistor connected in series to one end of the inductor, a second transistor connected in parallel to the other end of the inductor, a diode, and two capacitors connected in parallel to the other end of the inductor, respectively. Headlight control device of a vehicle, characterized in that configured. The method according to claim 1 or 2, The voltage step dividing means may include: a clamping circuit for clamping an input voltage, a first comparison circuit for driving a first transistor of the headlight driving means, a second comparison circuit for driving a second transistor of the headlight driving means, and And a reference voltage source circuit for supplying a reference voltage to the first and second comparison circuits. The method of claim 3, wherein The clamping circuit comprises a zener diode connected between an input voltage terminal and a ground side, and a diode connected in parallel between the zener diode and a resistor on the ground side. The method of claim 3, wherein The first comparison circuit includes a comparator having an inverting input terminal (−) connected to an input voltage terminal through a resistor and a non-inverting input terminal (+) connected to a reference voltage source circuit through a resistor. Headlight control device of the vehicle. The method of claim 3, wherein The second comparison circuit includes a comparator having an inverting input terminal (-) connected to an input voltage terminal through a resistor and a non-inverting input terminal (+) connected to the reference voltage source circuit. Headlight control device. The method according to claim 1 or 2, The boost / deceleration control means includes a voltage measuring circuit for measuring a voltage charged in a capacitor of the headlamp driving means, a sawtooth wave generating circuit for generating a sawtooth wave of a constant frequency, and an output signal and a sawtooth wave generating circuit of the voltage measuring circuit. And a comparator configured to compare the sawtooth signal of and drive the first and second transistors of the headlamp driving means to generate a PWM signal for boosting or depressing an input voltage. The method of claim 7, wherein The voltage measuring circuit includes a sawtooth wave generating means connected to a power input terminal of the headlamp through a resistor thereof, and a non-inverting input terminal (+) connected to a zener diode and a capacitor through a resistor. And an amplifier for connecting the power supply voltage supplied to the headlamp with a sawtooth wave. The method of claim 7, wherein The sawtooth wave generating circuit is configured to generate a comparator, a plurality of resistors and a capacitor for oscillation of a constant frequency, and a transistor, a capacitor, and a constant current for differentiating the output of the comparator to discharge the charging voltage of the capacitor at the rising edge of the waveform. A headlight control apparatus for a vehicle, comprising a transistor, a capacitor, and a zener diode generating a sawtooth wave by a current charging method.

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