JP5524936B2 - Lighting circuit controller - Google Patents

Description

  The present invention relates to an illumination circuit control device that controls turning on / off of a light source.

  Conventionally, for example, an illumination circuit control device 70 shown in FIG. 6 is well known as an illumination circuit control device that illuminates various devices of a vehicle (see Patent Document 1, etc.). The illumination circuit control device 70 is provided with an MPU (Micro Processing Unit) 71 that controls the illumination operation. The MPU 71 controls the illumination of the display unit 73 by switching on / off the light emitting diode 74 of the display unit 73 by turning on / off the transistor 72. In this case, when the transistor 72 is turned on, the light emitting diode 74 is turned on and the mark 75 is illuminated.

JP 2004-325324 A

  By the way, in the case of the lighting circuit control device 70 of Patent Document 1, when the power state of the vehicle, that is, the ignition switch is operated to an IG (Ignition) off state, the MPU 71 is not supplied with power and the MPU 71 stops. At this time, the control of the transistor 72 by the MPU 71 becomes impossible, and there is a current situation that the display device 73 is unconditionally turned off. That is, if the vehicle power supply is operated to turn off the IG, the display 73 is forcibly turned off, and it is impossible to maintain the display 73 in a lit state.

  Therefore, in recent vehicles, a technique has been studied in which the indicator 73 can be kept in a lighting state as long as the vehicle width lamp switch is on even when the vehicle power supply is switched on / off. By the way, when the lighting of the display device 73 is maintained, if the luminance of the display device 73 changes before and after the vehicle power supply is switched, it may appear as flickering of illumination. Therefore, there has been a need for development of a technique that can maintain lighting regardless of whether the power state of the vehicle is switched on / off, and can prevent the occurrence of lighting flickering when maintaining lighting.

  An object of the present invention is to provide an illumination circuit control device capable of maintaining lighting regardless of switching on / off of a vehicle power source and making it difficult to cause flickering of lighting at the time of switching.

  In order to solve the above problems, in the present invention, a first switch unit that turns on and off the energization of a light source that can be turned on by an illumination power source in a first path, and a second switch unit that turns on and off the light source in a second path; A connection switching circuit that switches between valid / invalid of lighting driving of the light source by an external control device, and a microcomputer that operates by a vehicle power source to control lighting of the light source, and the microcomputer, when activated, has the connection switching circuit The switch request signal is output to the second switch unit in an inactive state, and a pulsed control signal is output to the first switch unit in this state to turn on the light source by computer control. When the control is performed and the control is stopped, the control signal cannot be output, and the switching request signal is inverted and output. By switching the connection switching circuit to the second switch section valid state, the second switch section can be directly driven by the external pulse signal input from the external control device via the Zika line. The light source is controlled to be turned on by line control, and the microcomputer is provided with a signal output means for outputting a pulse of the control signal and a pulse of the switching request signal in synchronization with each other at the time of activation.

  According to the configuration of the present invention, when the vehicle power supply is turned on, the microcomputer is activated by the vehicle power supply. When the microcomputer is activated, supply of a pulse-shaped control signal from the microcomputer to the first switch unit is started, and lighting driving of the light source by computer control is started. At this time, for example, a Hi level signal switching request signal is output from the microcomputer to the connection switching circuit, and the connection switching circuit is set to the second switch section invalid state. For this reason, when the illumination power is turned on, the light source is controlled to be turned on by computer control rather than Zika line control.

  On the other hand, when the vehicle power supply is turned off, the microcomputer stops because power is not supplied to the microcomputer. When the microcomputer is stopped, it becomes impossible to output a control signal from the microcomputer to the first switch unit, so that computer control cannot be performed. However, at this time, the connection switching signal output from the microcomputer is inverted and the connection switching circuit is switched to the second switch portion valid state. Therefore, when the microcomputer is stopped, the computer control cannot be performed, but the light source can be driven to light by the Zika line control by the external control device. As a result, even if the microcomputer is stopped by turning off the vehicle power, the lighting of the light source is controlled by the Zika line control if the illumination power is turned on.

  Here, when the Zika line control is selected, if the vehicle power is turned on again, the lighting control of the light source is switched again from the Zika line control to the computer control. At this time, for each of the first switch unit and the connection switching circuit from the microcomputer, the output of the control signal is resumed to the first switch unit, and the switching request to switch the connection switch circuit to the second switch unit invalid state. The signal output is resumed. In the case of the present invention, when this signal is output, the pulse of the control signal and the pulse of the switching request signal are output in synchronization with each other, so that the timing for starting the lighting of the light source and switching the operation of the connection switching circuit is exactly the same. Therefore, it is possible to suppress flickering of illumination when switching from Zika line control to computer control.

  In the present invention, the microcomputer includes external signal input means for inputting the external pulse signal from the external control device, and the signal output means is synchronized with the external pulse signal when outputting the control signal. The gist is to output the control signal. According to this configuration, since the control signal is output in synchronization with the external pulse signal, the pulse cycle matches when switching from the Zika line control to the computer control. Therefore, it becomes possible to make it difficult to produce illumination flicker.

  The gist of the present invention is that the computer control is PWM control for setting the luminance of the light source by switching the duty ratio of the pulse of the control signal. According to this configuration, since the computer control is PWM control, it is possible to easily adjust the luminance of the light source by simply switching the duty ratio. Further, for example, the duty ratio can be adjusted in accordance with the fluctuation of the vehicle power supply, so that the luminance of the light source can be controlled to be constant.

  In the present invention, the microcomputer includes external signal input means for inputting the external pulse signal from the external control device, and the microcomputer outputs a PWM signal at a duty ratio corresponding to the external pulse signal, The gist is to drive the light source. According to this configuration, for example, when the brightness of the light source can be selected and operated by the external control device, the external control device outputs an external pulse signal having a duty ratio corresponding to the operation amount. When the PWM control of the light source is performed, the light source is controlled to be lighted by driving the first switch unit with a duty ratio corresponding to the external pulse signal. For this reason, the luminance of the light source can be appropriately switched to the luminance selected and operated by the external control device.

  The gist of the present invention is that the external control device is a rheostat operated when adjusting the luminance of the light source. According to this configuration, the luminance of the light source can be appropriately adjusted by operating the rheostat.

  In the present invention, the first switch unit is a first switching element that is driven and controlled during the computer control, and the second switch unit is a second switching element that is driven and controlled during the Zika line control. The connection switching circuit selects a third switching element for switching the computer control or the Zika line control based on the switching request signal inputted from the microcomputer, and the third switching element selects the Zika line control. And a fourth switching element that drives and controls the second switching element based on the external pulse signal input from the external control device. According to this configuration, the illumination circuit control device can be provided as a general-purpose circuit using switching elements.

  According to the present invention, lighting can be maintained regardless of whether the vehicle power supply is switched on / off, and flickering of illumination can be made difficult to occur at the time of switching.

The electrical block diagram of the illumination circuit control apparatus of one Embodiment. The electrical block diagram which shows the operation state of the illumination circuit control apparatus at the time of PWM control. The electrical block diagram which shows the operation state of the illumination circuit control apparatus at the time of Zika line control. The timing chart when the output timing of a PWM signal and a switch request signal has shifted | deviated. The timing chart when the output timing of a PWM signal and a switching request signal is united. The block diagram of the conventional illumination circuit control apparatus.

Hereinafter, an embodiment of a lighting circuit control apparatus embodying the present invention will be described with reference to FIGS.
As shown in FIG. 1, the vehicle is provided with an illumination circuit control device 1 that illuminates various devices of the vehicle. The lighting circuit control device 1 of this example can illuminate these devices in order to enable, for example, the position and identification of a manual control device, tell tale, indicator, etc. in the vehicle. The illumination circuit control device 1 is provided with a microcomputer 2 that controls the illumination operation of the illumination circuit control device 1 and an LED (light emitting diode) 3 that emits illumination light. The LED 3 corresponds to a light source.

  The lighting circuit control device 1 of this example can control lighting of the LED 3 by PWM (Pulse Width Modulation) control by the microcomputer 2 when the vehicle power source (ignition switch) is on and the microcomputer 2 is activated. The PWM control is a control method for setting the luminance of the LED 3 by switching the duty ratio of the pulsed PWM signal Spl output from the microcomputer 2, and sets the luminance of the LED 3 to a value based on the duty ratio. The duty ratio is a time ratio of the pulse width of the Hi level in one signal cycle. The vehicle power on state refers to a state in which the ignition switch is in either an IG (Ignition) on state or an ST (Starter) on state, for example. Note that the PWM signal Spl corresponds to a control signal.

  Further, the lighting circuit control device 1 can control the lighting of the LED 3 by the Zika line control by the rheostat 4 when the vehicle power supply is in an off state and the microcomputer 2 is stopped. The Zika line control is a function for maintaining the LED 3 in the lighting state even when the microcomputer 2 is stopped by turning off the vehicle power. The LED 3 is directly controlled by the pulsed rheostat signal Srs input from the rheostat 4. It is. The vehicle power supply off state refers to a state where the ignition switch is in the IG off state. The rheostat 4 corresponds to an external control device, and the rheostat signal Srs corresponds to an external pulse signal.

  A positive voltage (plus voltage) illumination voltage ILL + is input to the anode of the LED 3 via a voltage adjusting resistor 5. The illumination voltage ILL + is turned on with the in-vehicle battery as a power source when the on / off switch 6 of the LED 3 is turned on. The on / off switch 6 is, for example, a vehicle width lamp switch operated when switching on / off of the headlight of the vehicle. The illumination voltage ILL + corresponds to the illumination power source.

  The lighting circuit control device 1 can switch between enabling / disabling of the first transistor Tr1 driven during PWM control by the microcomputer 2, the second transistor Tr2 driven during Zika line control by the rheostat 4, and the second transistor Tr2. A connection switching circuit 7 is provided. In addition, the connection switching circuit 7 is provided with a third transistor Tr3 that switches to PWM control or Zika line control, and a fourth transistor Tr4 that receives PWM control by the rheostat signal Srs during Zika line control. The first transistor Tr1 corresponds to the first switch part and the first switching element, and the second transistor Tr2 constitutes the second switch part and the second switching element. The third transistor Tr3 corresponds to a third switching element, and the fourth transistor Tr4 corresponds to a fourth switching element.

  The first transistor Tr1 is an NPN bipolar transistor. The first transistor Tr1 has a collector terminal connected to the cathode of the LED 3, an emitter terminal connected to the ground, and a base terminal connected to the PWM control terminal 9 of the microcomputer 2 via the resistor 8. A resistor 10 that determines a base-emitter voltage is connected between the base and emitter of the first transistor Tr1. In the case of this example, the current path passing through the LED 3 and the first transistor Tr1 is the first path R1. The first transistor Tr1 corresponds to the first switch unit and the first switching element.

  The second transistor Tr2 is an NPN bipolar transistor. The second transistor Tr2 has a collector terminal connected to the middle point P1 of the LED 3 and the first transistor Tr1, an emitter terminal connected to the ground, and a base terminal connected to the fourth transistor via a series circuit 13 of two resistors 11 and 12. It is connected to the collector terminal of Tr4. A resistor 14 that determines a base-emitter voltage is connected between the base and emitter of the second transistor Tr2. In this example, the path passing through the LED 3 and the second transistor Tr2 is the second path R2.

  The third transistor Tr3 is an NPN bipolar transistor. The third transistor Tr3 has a collector terminal connected to the middle point P2 of the resistors 11 and 12, an emitter terminal connected to the ground, and a base terminal connected to the operation switching terminal 16 of the microcomputer 2 via the resistor 15. . The series circuit 13 becomes a voltage dividing resistor circuit to the collector terminal of the third transistor Tr3, and the voltage between the resistors 11 and 12, that is, the voltage at the middle point P2 is supplied. A resistor 17 that determines a base-emitter voltage is connected between the base and emitter of the third transistor Tr3.

  The fourth transistor Tr4 is a PNP-type bipolar transistor. The fourth transistor Tr4 has a collector terminal connected to the second transistor Tr2 and the third transistor Tr3, an emitter terminal connected to the illumination voltage ILL +, and a base terminal connected via the resistor 18 to the rheostat connection terminal 19 of the lighting circuit control device 1. It is connected to the.

  The rheostat 4 is provided with a rheostat transistor 20 for generating / outputting a rheostat signal Srs. The rheostat transistor 20 is an NPN bipolar transistor. The rheostat transistor 20 has a collector terminal connected to the rheostat signal output terminal 21 on the rheostat 4 side, an emitter terminal connected to the ground, and a base terminal connected to the PWM signal generation circuit 22. The rheostat signal output terminal 21 receives a negative voltage (minus voltage) illumination voltage ILL−.

  The PWM signal generation circuit 22 drives and controls the rheostat transistor 20 by applying a pulse signal having a duty ratio corresponding to an operation amount of a rheostat switch (not shown) to the base terminal of the rheostat transistor 20. As a result, the rheostat 4 supplies a pulsed rheostat signal Srs having a pulse width corresponding to the duty ratio to the base terminal of the fourth transistor Tr4 via the rheostat signal output terminal 21 and the rheostat connection terminal 19. Therefore, the fourth transistor Tr4 is driven and controlled by PWM control by the rheostat 4. The rheostat 4 always outputs the rheostat signal Srs using the on-vehicle battery as a power source regardless of whether the vehicle power supply is on or off.

  The microcomputer 2 receives the ignition voltage IG + via the I / F circuit 23. When the vehicle power supply is turned on, the ignition voltage IG + is turned on using the in-vehicle battery as a power supply. Therefore, the microcomputer 2 starts the ignition voltage IG + to the power supply when the power supply state is switched to the on state. The ignition voltage IG + corresponds to the vehicle power supply.

  The microcomputer 2 is provided with an ignition voltage monitor unit 24 that monitors the ignition voltage IG +. The ignition voltage monitor unit 24 sequentially monitors the value of the ignition voltage IG + while the microcomputer 2 is activated.

  The microcomputer 2 is provided with a PWM control unit 25 that performs PWM control of the first transistor Tr1 to turn on the LED 3 when the microcomputer 2 is activated. The PWM control unit 25 applies the PWM signal Spl from the PWM control terminal 9 to the base terminal of the first transistor Tr1, and switches the first transistor Tr1 on and off at high speed, whereby a current flows through the first path R1. The state is formed intermittently, and the LED 3 is turned on with a desired luminance. That is, when the first transistor Tr1 is turned on, the LED 3 is lit, and when the first transistor Tr1 is turned off, the LED 3 is turned off. It seems to be lit continuously. The brightness of the LED 3 is determined according to the duty ratio of the PWM signal Spl. When the duty ratio is high, the brightness is high, and when the duty ratio is low, the brightness is low.

  The microcomputer 2 is provided with a switching control unit 26 that switches the lighting control of the illumination circuit control device 1 to either PWM control or Zika line control. The switching control unit 26 of this example raises the switching request signal Sch output from the operation switching terminal 16 to the Hi level when the microcomputer 2 is activated. Thereby, the third transistor Tr3 is turned on, and the path of the current Ia shown in FIG. 2 flowing from the fourth transistor Tr4 to the third transistor Tr3 is formed. That is, the connection switching circuit 7 is switched to the second transistor invalid state. Therefore, even if the rheostat signal Srs is supplied to the fourth transistor Tr4, the second transistor Tr2 does not operate. Therefore, when the microcomputer 2 is activated, the first transistor Tr1 is enabled and the second transistor Tr2 is disabled.

  On the other hand, since the ignition voltage IG + is not supplied when the microcomputer 2 is stopped, the switching control unit 26 lowers the switching request signal Sch output from the operation switching terminal 16 to the Lo level. As a result, the third transistor Tr3 is turned off, and the path of the current Ib shown in FIG. 3 flowing from the fourth transistor Tr4 to the second transistor Tr2 is formed. That is, the connection switching circuit 7 is switched to the second transistor valid state. Therefore, it is possible to drive and control the on / off of the second transistor Tr2 through the drive control of the fourth transistor Tr4 by the rheostat signal Srs. Therefore, when the microcomputer 2 is stopped, the first transistor Tr1 is disabled and the second transistor Tr2 is enabled.

  The PWM control unit 25 adjusts the duty ratio according to the fluctuation of the voltage of the in-vehicle battery so that the LED 3 is lit with a constant luminance even if the voltage of the in-vehicle battery (illumination voltage ILL +, ignition voltage IG +) fluctuates. In this case, the PWM control unit 25 monitors the difference between the voltage monitored by the ignition voltage monitoring unit 24 and the target voltage, and adjusts the duty ratio according to the difference, thereby controlling the luminance of the LED 3 to be constant.

  The PWM control unit 25 sets the luminance of the LED 3 according to the operation amount set by the rheostat 4. In this case, the microcomputer 2 is provided with a rheostat signal input unit 27 for acquiring the rheostat signal Srs output from the rheostat 4. The rheostat signal input unit 27 is connected to the midpoint P3 between the resistor 18 of the fourth transistor Tr4 and the rheostat connection terminal 19 via the I / F circuit 28. The rheostat signal input unit 27 inputs the voltage at the midpoint P3 as the rheostat signal Srs via the I / F circuit 28. When the PWM signal Spl is output, the PWM control unit 25 outputs the PWM signal Spl as a waveform signal having a duty ratio corresponding to the duty ratio of the rheostat signal Srs. As a result, the PWM signal Spl takes a pulse signal corresponding to the rheostat signal Srs, and the LED 3 is turned on with the luminance set by the rheostat 4. The rheostat signal input unit 27 corresponds to external signal input means.

  Here, in the situation where the LED 3 is lit, when the lighting control of the LED 3 is switched from the Zika line control to the microcomputer control as the vehicle power source is switched from IG OFF to IG ON, as shown in FIG. It is assumed that the timing is shifted between the rising edge of the Spl pulse and the rising edge of the switching request signal Sch. At this time, as shown in the figure, when the pulse rising edge of the PWM signal Spl is slower than the pulse rising edge of the switching request signal Sch, a time zone in which the LED 3 disappears momentarily occurs, and this is caused as flickering of illumination. It becomes. Although not shown, when the pulse rise of the PWM signal Spl is faster than the pulse rise of the switching request signal Sch, mutual PWM drive interference occurs, which also causes flickering.

  Therefore, as shown in FIG. 1, the microcomputer 2 of this example is provided with an output timing control unit 29 that controls the timing of the pulse rising of the PWM signal Spl and the pulse rising of the switching request signal Sch. When outputting the PWM signal Spl from the PWM control terminal 9 during PWM control, the output timing control unit 29 outputs the PWM signal Spl in synchronization with the pulse of the switching request signal Sch. That is, the output timing control unit 29 adjusts and outputs the output timing of both signals so that the pulse rising of the PWM signal Spl and the pulse rising of the switching request signal Sch take the same timing. The output timing control unit 29 corresponds to a signal output unit.

  Further, the output timing control unit 29 of this example outputs these signals in synchronization with the rheostat signal Srs when the PWM signal Spl and the switching request signal Sch are output. By the way, when switching from the Zika line control to the PWM control, if the pulse rising of the PWM signal Spl occurs immediately after the pulse rising of the rheostat signal Srs, the turn-off interval becomes narrower than before. It causes flickering of lighting. Therefore, the output timing control unit 29 of this example outputs the PWM signal Spl and the switching request signal Sch in synchronization with the cycle of the rheostat signal Srs when switching from the Zika line control to the PWM control.

Next, operation | movement of the illumination circuit control apparatus 1 of this example is demonstrated using FIG.2, FIG.3 and FIG.5.
First, as shown in FIG. 2, when the vehicle power supply (ignition switch) is operated from IG OFF to IG ON, the ignition voltage IG + is supplied to the microcomputer 2 and the microcomputer 2 is switched to the activated state. At this time, the PWM control unit 25 starts the PWM control by outputting the PWM signal Spl from the PWM control terminal 9. Further, the switching control unit 26 starts outputting the Hi level signal as the switching request signal Sch from the operation switching terminal 16, turns on the third transistor Tr3, and sets the connection switching circuit 7 to the second switching element invalid state. However, since the lighting / extinguishing switch 6 is still turned off here, the illumination voltage ILL + is not supplied, and the LED 3 is kept off.

  When the microcomputer 2 is started up, the illumination voltage ILL + is input to the collector terminal of the first transistor Tr1 and the emitter terminal of the fourth transistor Tr4 when the on / off switch 6 is operated from the off position to the on position. As a result, the first transistor Tr1 and the fourth transistor Tr4 can be driven. At this time, the rheostat 4 supplies the pulsed rheostat signal Srs to the fourth transistor Tr4.

  When the microcomputer 2 is in the activated state and the illumination voltage ILL + is in the supplied state, a current flows through the fourth transistor Tr4 at the pulse generation timing of the rheostat signal Srs. Here, since the third transistor Tr3 is turned on, the current Ia of FIG. 2 from the fourth transistor Tr4 to the third transistor Tr3 flows through the connection switching circuit 7, and no current is supplied to the second transistor Tr2. . That is, the second transistor Tr2 is disabled under the condition that the first transistor Tr1 is enabled.

  When the microcomputer 2 is in the activated state and the illumination voltage ILL + is in the supply state, the LED 3 is controlled to be lit by PWM control of the microcomputer 2. Here, since the second transistor Tr2 is disabled, the current I1 in FIG. 2 flows through the first path R1 each time a pulse is generated in the PWM signal Spl, and the first transistor Tr1 is turned on / off. The current I1 flows intermittently through the first path R1. Thereby, LED3 lights with the brightness | luminance according to the duty ratio of PWM signal Spl.

  Moreover, the PWM control part 25 controls the brightness | luminance of LED3 uniformly by adjusting the duty ratio of PWM signal Spl according to the fluctuation | variation of the voltage of a vehicle-mounted battery at the time of PWM control. That is, the duty ratio of the PWM signal Spl is adjusted so that the LED 3 takes a constant luminance even when the voltage of the in-vehicle battery fluctuates and the ignition voltage IG + and the illumination voltage ILL + fluctuate. Further, the PWM control unit 25 sets the luminance of the LED 3 to the luminance based on the operation amount of the rheostat 4 by adjusting the duty ratio of the PWM signal Spl based on the rheostat signal Srs acquired from the rheostat 4.

  Subsequently, as shown in FIG. 3, if the vehicle power supply is operated from IG on to IG off while the lighting / extinguishing switch 6 is on, the microcomputer 2 is not supplied with the ignition voltage IG +. Switches to a stopped state. At this time, the PWM control unit 25 becomes inoperable, so that the PWM control by the microcomputer 2 cannot be performed. Further, since the switching control unit 26 is also disabled, the Lo level signal is inverted and output as the switching request signal Sch from the operation switching terminal 16. Therefore, the third transistor Tr3 is turned off, and the connection switching circuit 7 is set to the second switching element effective state.

  When the microcomputer 2 is in the stop state and the illumination voltage ILL + is in the supply state, a current flows through the fourth transistor Tr4 at the pulse generation timing of the rheostat signal Srs. Here, since the third transistor Tr3 is turned off, the current Ib of FIG. 3 from the fourth transistor Tr4 to the second transistor Tr2 flows through the connection switching circuit 7, and no current flows through the third transistor Tr3. . That is, the second transistor Tr2 is enabled under the condition that the first transistor Tr1 is disabled.

  When the microcomputer 2 is in the stop state and the illumination voltage ILL + is in the supply state, the LED 3 is directly controlled to be lit by the rheostat 4 by the Zika line control of the rheostat signal Srs (PWM control by the rheostat 4). Here, since the second transistor Tr2 is effective, every time a pulse is generated in the rheostat signal Srs, the fourth transistor Tr4 is turned on and the current Ib flows, and the second transistor Tr2 is switched on / off. . Then, whenever the second transistor Tr2 is turned on, the current I2 of FIG. 3 flows intermittently through the second path R2. Thereby, LED3 lights with the brightness | luminance according to the duty ratio of the rheostat signal Srs.

  Here, it is assumed that the vehicle power source is operated again from IG OFF to IG ON in a situation where the illumination voltage ILL + is in a supply state. That is, it is assumed that the lighting control of the LED 3 is returned from the Zika line control to the PWM control. At this time, the PWM control unit 25 resumes the output of the PWM signal Spl and starts executing the PWM control. The switching control unit 26 raises the switching request signal Sch output from the operation switching terminal 16 from the Lo level to the Hi level, and turns on the third transistor Tr3 again by the Hi level signal.

  At this time, as shown in FIG. 5, the output timing control unit 29 adjusts the output timing of these signals so that the pulse rising edge of the PWM signal Spl and the pulse rising edge of the switching request signal Sch match. That is, the output timing control unit 29 outputs the PWM signal Spl and the switching request signal Sch in a state where the rising edges of the pulses are synchronized. For this reason, it is possible to make it difficult for the LED 3 to flicker when switching from the Zika line control to the PWM control.

  The output timing controller 29 outputs the PWM signal Spl and the switching request signal Sch in synchronization with the PWM cycle of the rheostat signal Srs. That is, when the lighting control is switched from the Zika line control to the PWM control, the output timing control unit 29 outputs the PWM signal Spl and the switching request signal Sch at a timing determined from the pulse cycle of the rheostat signal Srs. Is output in synchronization with the rheostat signal Srs. Thereby, it is possible to make the flickering of the LED 3 less likely to occur when switching from the Zika line control to the PWM control.

  As described above, in the case of this example, when the lighting control of the LED 3 is switched from the Zika line control to the PWM control under the situation where the illumination voltage ILL + is supplied, the output timings of the PWM signal Spl and the switching request signal Sch are matched. In the state, both these signals are output. Therefore, the timing of the start of lighting of the LED 3 by the pulse of the PWM signal Spl and the switching of the connection switching circuit 7 to the second transistor invalid state exactly match. For this reason, it is possible to make it difficult for the LED 3 to flicker.

  At this time, the PWM signal Spl and the switching request signal Sch are also output at a timing synchronized with the rheostat signal Srs. That is, when the microcomputer 2 outputs the PWM signal Spl and the switching request signal Sch, it is output in synchronization with the cycle of the rheostat signal Srs. As a result, when switching from the Zika line control to the PWM control, the lighting cycle of the LED 3 does not change significantly, and the effect of suppressing the flickering of the LED 3 is enhanced.

According to the configuration of the present embodiment, the following effects can be obtained.
(1) When the lighting control of the LED 3 is switched from the Zika line control to the PWM control when the illumination voltage ILL + is turned on, the PWM signal Spl and the switching request signal Sch are output in a state where the timing of the pulses is matched. For this reason, the timing when the current flows through the LED 3 and the timing when the connection switching circuit 7 switches to the second switching element invalid state are aligned. Therefore, when switching from Zika line control to computer control, it is possible to make it difficult for the LED 3 to flicker.

  (2) When the PWM signal Spl and the switching request signal Sch are output at the same timing when switching from the Zika line control to the PWM control, these signals are output in synchronization with the rheostat signal Srs. For this reason, when switching from the Zika line control to the computer control, the pulse cycle matches before and after the switching. Therefore, it is possible to make the flickering of the LED 3 less likely to occur.

(3) Since the computer control is PWM control, the brightness of the LED 3 can be easily adjusted by simply switching the duty ratio.
(4) The voltage of the in-vehicle battery (ignition voltage IG +) is monitored, the duty ratio of the PWM control is switched according to the voltage fluctuation of the in-vehicle battery, and the brightness of the LED 3 is adjusted to be constant. For this reason, even if the voltage of a vehicle-mounted battery fluctuates, the brightness | luminance of LED3 can be controlled uniformly by adjusting the duty ratio of PWM control.

  (5) The rheostat signal Srs is input to the microcomputer 2 and the duty ratio of the PWM control is set to a ratio corresponding to the duty ratio of the rheostat signal Srs. For this reason, the luminance of the LED 3 can be appropriately switched to the luminance selected and operated by the rheostat 4.

  (6) Since the rheostat 4 is a member that always starts with the on-vehicle battery as a power source, the rheostat signal Srs can be constantly supplied to the illumination circuit control device 1 regardless of the power state of the vehicle.

(7) Since the illumination circuit control device 1 is mainly composed of transistors, the illumination circuit control device 1 can be provided as a general-purpose circuit using transistors.
Note that the embodiment is not limited to the configuration described so far, and may be modified as follows.

The on / off switch 6 is not limited to the vehicle width lamp switch, and can be changed to another switch mounted on the vehicle.
The rheostat 4 is not limited to always starting the vehicle-mounted battery as a power source, and may be operable only when the illumination voltage ILL + is supplied, for example.

  The operation switching of the connection switching circuit 7 may be, for example, a state in which the second transistor is disabled when a Lo level signal is received and a state where the second transistor is enabled when a Hi level signal is received.

The external control device is not limited to the rheostat 4 and may be any device that can control the second transistor Tr2 from the outside.
The connection switching circuit 7 is not limited to a circuit composed of the third transistor Tr3 and the fourth transistor Tr4, and can be changed to any other circuit as long as it can switch the Zika line control between valid and invalid.

The computer control is not limited to PWM control, and can be changed to other control.
-Zika line control is not limited to PWM control, For example, control with a fixed pulse width may be sufficient.

The light source is not limited to the LED 3, and other members such as a lamp may be used.
The first transistor Tr1 to the fourth transistor Tr4 are not limited to bipolar transistors, and other types of transistors may be used.

The first switch unit to the fourth switch unit are not limited to transistors, and other switch members may be used.
The vehicle power supply on state may include an ACC (Accessory) on state.

The lighting circuit control device 1 is not limited to the circuit configuration described in the embodiment, and can be appropriately changed to other configurations.
The lighting circuit control device 1 includes a process of matching the output timing of the PWM signal Spl and the switching request signal Sch when switching from the Zika line control to the PWM control, and a process of outputting these signals in synchronization with the rheostat signal Srs. It is not limited to doing both. That is, at least the former process may be performed.

  DESCRIPTION OF SYMBOLS 1 ... Lighting circuit control apparatus, 2 ... Microcomputer, 3 ... LED as a light source, 4 ... Rheostat as an external control device, 7 ... Connection switching circuit, 27 ... Rheostat signal input part as external signal input means, 29 ... Signal Output timing control unit as output means, ILL + ... illumination voltage as illumination power source, IG + ... ignition voltage as vehicle power source, R1 ... first route, R2 ... second route, Tr1 ... first switch unit and first switching element Tr2... Second transistor constituting the second switch section and second switching element, Tr3... Third transistor as the third switching element, Tr4... Fourth transistor as the fourth switching element, Sch ... switching request signal, Spl ... PWM signal as control signal, Srs ... external pulse signal Rheostat signal.

Claims (6)

A first switch unit for turning on / off the energization of a light source that can be turned on by an illumination power source in a first path, a second switch unit for turning on / off the light source in a second path, and valid / invalid of lighting driving of the light source by an external control device A connection switching circuit for switching between, and a microcomputer that operates by a vehicle power supply to control the lighting of the light source,
When the microcomputer is activated, it outputs a switching request signal to the connection switching circuit, thereby disabling the connection switching circuit in the second switch section, and in this state, a pulse-like control signal is sent to the first switch section. By outputting, the light source is controlled to be turned on by computer control. Conversely, when stopped, the control signal cannot be output, and further, the switching request signal is inverted and output, whereby the connection switching circuit is By switching to the two-switch unit valid state and enabling the second switch unit to be driven directly by an external pulse signal input from the external control device via the Zika line, the lighting of the light source is controlled by Zika line control. ,
The microcomputer includes a signal output unit that outputs a pulse of the control signal and a pulse of the switching request signal in synchronization with each other when the microcomputer is activated. The microcomputer comprises external signal input means for inputting the external pulse signal from the external control device,
The lighting circuit control device according to claim 1, wherein the signal output means outputs the control signal in synchronization with the external pulse signal when outputting the control signal. 3. The lighting circuit control device according to claim 1, wherein the computer control is PWM control that sets a luminance of the light source by switching a duty ratio of a pulse of the control signal. 4. The microcomputer comprises external signal input means for inputting the external pulse signal from the external control device,
4. The lighting circuit control device according to claim 3, wherein the microcomputer outputs a PWM signal with a duty ratio corresponding to the external pulse signal to drive the light source to turn on. The illumination circuit control device according to any one of claims 1 to 4, wherein the external control device is a rheostat operated when adjusting the luminance of the light source. The first switch unit is a first switching element that is driven and controlled during the computer control, and the second switch unit is a second switching element that is driven and controlled during the Zika line control,
The connection switching circuit selects a third switching element for switching the computer control or the Zika line control based on the switching request signal input from the microcomputer, and the third switching element selects the Zika line control. And a fourth switching element that drives and controls the second switching element based on the external pulse signal input from the external control device. Lighting circuit control device according to claim 1.