JP2006172806A - Lighting control circuit of vehicular lighting fixture - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To convert a plurality of analog signals to digital signals by a single analog-to-digital converting means. <P>SOLUTION: An input voltage of a switching regulator 12 and voltages formed on both ends of an LED 1 are captured into switches SW 100 to SW 102 of a multiplexer 16 respectively, the captured voltages are selected in the sequential order and are outputted from the multiplexer 16 to an A/D converter terminal 30 of a microcomputer 18, and the inputted voltages are converted to digital signals using the A/D converter built in the microcomputer 18, while switching signals for ON/OFF operating the switch SW 1 are formed based on the converted digital signals, then ON/OFF operation of the SW 1 is controlled in accordance with the formed switching signals. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a lighting control circuit for a vehicular lamp, and more particularly, to a lighting control circuit for a vehicular lamp configured to control lighting of a semiconductor light source composed of a semiconductor light emitting element.

  2. Description of the Related Art Conventionally, a vehicular lamp using a semiconductor light emitting element such as an LED (Light Emitting Diode) as a light source is known, and this type of vehicular lamp has a lighting control circuit for controlling the lighting of the LED. Has been implemented.

  When configuring the lighting control circuit, a switching regulator including a switching element and a transformer is used, and an output block including a rectifying diode and a smoothing capacitor is used. A configuration is adopted in which the energy is stored in the transformer, the electromagnetic energy stored in the transformer is released from the secondary side of the transformer to the output block when the switching element is turned off, and the electromagnetic energy is supplied as light emission energy from the output block to the LED. ing. In this case, when supplying light emission energy to each load in order by a time sharing method for a plurality of loads composed of LEDs, for example, as an output block, a plurality of connections are provided on the secondary side of the transformer. There has been proposed a light source selection unit that supplies light emission energy to each load in order via each connection unit (see Patent Document 1). In this lighting control circuit, when light emission energy is supplied to each load in turn, the on / off operation of the switching element of the switching regulator is controlled according to each load, and the switching element of each connection portion is turned on in turn. Is supposed to do. However, no consideration is given to controlling the switching element of the switching regulator and the switching element of each connection portion with a microcomputer.

  When controlling the on / off operation of a switching element such as a switching regulator using a microcomputer, for example, the microcomputer executes arithmetic processing related to generation of a switching signal for turning on / off the switching element of the switching regulator. The on / off operation of the switching element can be controlled by applying the switching signal obtained by the processing to the switching element. Furthermore, by detecting the voltage applied to the LED and the current flowing through the LED and adjusting the on-duty of the switching signal based on the detection signal, the output voltage and output current of the switching regulator can be feedback controlled. In addition, the input voltage input to the switching regulator is detected, and when an abnormality in the input voltage is detected, control to stop the switching regulator operation or derating control to reduce the output current of the switching regulator is performed. can do. In this case, an analog signal related to the LED current (output current), voltage (output voltage), or input voltage of the switching regulator is converted into a digital signal using an A / D converter, and the digital signal converted by the A / D converter The signal is used as digital data indicating the state of the LED and the power supply. When converting three analog signals into digital signals, it is possible to adopt a configuration in which three A / D converters are built in the microcomputer or three A / D converters are provided outside the microcomputer. it can.

JP 2004-134146 A (pages 3 to 6, FIG. 1)

  However, when an A / D converter is provided corresponding to the analog signal to be detected, when a plurality of LEDs are to be detected, such as a time-sharing method or an independent method, the A / D converter every time the number of LEDs increases. The number of must be increased. In particular, when detecting the current and voltage of the LED, it is necessary to incorporate two A / D converters in the microcomputer or to arrange them outside the microcomputer each time the number of LEDs increases. For this reason, if A / D converters are provided according to the number of analog signals to be detected, the number of components increases, the mounting area increases, and the cost increases.

  The present invention has been made in view of the above-described problems of the prior art, and an object thereof is to convert a plurality of analog signals into digital signals by a single analog / digital conversion means.

  To achieve the above object, in the lighting control circuit for a vehicular lamp according to claim 1, an input voltage from a power source is converted into electromagnetic energy and released by an on / off operation of a switching element connected to a transformer or a coil. A switching regulator, energy propagation means for propagating electromagnetic energy emitted from the switching regulator as light emission energy to a semiconductor light source, and at least one of the power source and the semiconductor light source as a detection target, indicating a state quantity of the detection target A selection unit that takes in a plurality of analog signals, sequentially selects and outputs a single analog signal from the plurality of captured analog signals, and an analog / digital unit that sequentially converts the analog signals output from the selection unit into digital signals Conversion means and the analog digital Generates switching signals based on the digital signal converted by the converting means, has a configuration comprising a control means for controlling the on-off operation of the switching element in accordance with a switching signal wherein the generating.

  (Operation) When a plurality of analog signals indicating the state quantity to be detected are converted into digital signals, a single analog signal is sequentially selected from the plurality of analog signals by the selection means, and the analog signal selected by the selection means Is converted to digital signals sequentially by analog / digital conversion means, so that even if the number of analog signals to be detected increases, multiple analog signals can be converted to digital signals by a single analog / digital conversion means. Therefore, the configuration can be simplified and the cost can be reduced.

  In the lighting control circuit for the vehicular lamp according to claim 2, a plurality of switching regulators that convert and release the input voltage from the power source into electromagnetic energy by the on / off operation of the switching element connected to the transformer or the coil, A plurality of energy propagation means for propagating electromagnetic energy emitted from the switching regulator to a plurality of different semiconductor light sources as emission energy, and at least one of the power supply and the plurality of semiconductor light sources as a detection target, A selection unit that takes in a plurality of analog signals indicating a state quantity to be detected, sequentially selects and outputs a single analog signal from the plurality of acquired analog signals, and sequentially converts the analog signals generated by the selection unit to digital Analog / digital conversion means to convert to signal The digital signal converted by the analog-digital conversion means generates switching signals based on, and control means for controlling the on-off operation of the switching element and provided comprising configure accordance switching signal the generating.

(Operation) When a plurality of analog signals indicating the state quantity to be detected are converted into digital signals, a single analog signal is sequentially selected from the plurality of analog signals by the selection means, and the analog signal selected by the selection means Is converted to digital signals sequentially by analog / digital conversion means, so that even if the number of analog signals to be detected increases, multiple analog signals can be converted to digital signals by a single analog / digital conversion means. Therefore, the configuration can be simplified and the cost can be reduced.
In the lighting control circuit for a vehicular lamp according to claim 3, the switching regulator that converts the input voltage from the power source into electromagnetic energy by the on / off operation of the switching element connected to the transformer or the coil and releases the electromagnetic energy, and the switching regulator A plurality of energy propagation means for propagating the emitted electromagnetic energy to a plurality of different semiconductor light sources as light emission energy, and at least one of the power source and the plurality of semiconductor light sources as a detection target; A selection unit that captures a plurality of analog signals indicating state quantities, sequentially selects and outputs a single analog signal from the captured plurality of analog signals, and sequentially converts the analog signal output from the selection unit into a digital signal Analog-to-digital conversion means, and Generates switching signals based on the digital signal converted by the analog-digital conversion means, and the arrangement comprising a control means for controlling the on-off operation of the switching element in accordance with a switching signal wherein the generating.
(Operation) When a plurality of analog signals indicating the state quantity to be detected are converted into digital signals, a single analog signal is sequentially selected from the plurality of analog signals by the selection means, and the analog signal selected by the selection means Is converted to digital signals sequentially by analog / digital conversion means, so that even if the number of analog signals to be detected increases, multiple analog signals can be converted to digital signals by a single analog / digital conversion means. Therefore, the configuration can be simplified and the cost can be reduced.

  The lighting control circuit for a vehicle lamp according to claim 4 is the lighting control circuit for a vehicle lamp according to any one of claims 1, 2, or 3, wherein the analog / digital conversion means is the selection unit. The analog signal from the means is converted into a digital signal after a predetermined time has elapsed.

(Operation) When an analog signal is converted into a digital signal, a CR circuit (filter circuit) is connected to the analog / digital conversion means by converting the analog signal output from the selection means into a digital signal after a predetermined time has elapsed. Even if the waveform of the analog signal is reduced by the capacitance component of the CR circuit, an accurate digital signal can be obtained and an erroneous switching signal can be prevented from being generated.
In the lighting control circuit for a vehicle lamp according to claim 5, in the lighting control circuit for a vehicle lamp according to any one of claims 1, 2, 3, or 4, the selection means is the detection target. When a change occurs, the analog signal related to the detection target in which the change has occurred is selected in preference to other analog signals.
(Operation) When a change occurs in the detection target, for example, when an abnormality occurs in the detection target, detection is performed by selecting many analog signals in relation to the detection target in which the change has occurred in preference to other analog signals. It is possible to smoothly perform feedback control or derating control according to the change of the object.

  As apparent from the above description, the lighting control circuit for a vehicle lamp according to claim 1 can simplify the configuration and contribute to cost reduction.

  According to the lighting control circuit for the vehicular lamp according to the second aspect, the configuration can be simplified and the cost can be reduced.

  According to the lighting control circuit for the vehicular lamp according to the third aspect, the configuration can be simplified, and the cost can be reduced.

  According to the fourth aspect, an accurate digital signal can be obtained, and an erroneous switching signal can be prevented from being generated.

  According to the fifth aspect, it is possible to smoothly perform the feedback control or the derating control accompanying the change of the detection target.

  Next, embodiments of the present invention will be described according to examples. FIG. 1 is a circuit configuration diagram of a lighting control circuit for a vehicular lamp according to an embodiment of the present invention, FIG. 2 is a circuit configuration diagram of a switching element constituting the switch and its driving circuit, and FIG. 3 is a switch for a multiplexer. FIG. 4 is a waveform diagram for explaining the operation of the multiplexer, FIG. 5 is a waveform diagram for explaining the compare match processing in the microcomputer, and FIG. FIG. 7 is a circuit configuration diagram showing an embodiment when using a time-sharing switching regulator, FIG. 7 is a circuit configuration diagram showing an embodiment when using an independent switching regulator, and FIG. 8 is a forward scheme. FIG. 9 is a circuit configuration diagram showing an embodiment when using a switching regulator of FIG. FIG. 10 is a circuit configuration diagram showing an embodiment when a step-down switching regulator is used, and FIG. 11 is a circuit configuration diagram when using a step-up switching regulator. It is a circuit block diagram which shows an Example.

  In these drawings, a lighting control circuit 10 for a vehicular lamp is a switching regulator 12 and an output block 14 for an LED 1 as a semiconductor light-emitting element constituting a semiconductor light source as an element of a vehicular lamp (light-emitting element). And a multiplexer 16 and a microcomputer (hereinafter referred to as a microcomputer) 18.

  As a semiconductor light source serving as a load of the output block 14 instead of the LED 1, a plurality of LEDs connected in series with each other or a plurality of LEDs connected in series are used as a light source block, and a plurality of light source blocks are used. Those connected in parallel can also be used. In addition, each semiconductor light source can be configured as a light source for various vehicle lamps such as a headlamp, a stop & tail lamp, a fog lamp, and a turn signal lamp.

  The switching regulator 12 includes a switch (switching element) SW1 and a transformer T1, and one end side of the primary winding L1 of the transformer T1 is connected to a plus terminal of the in-vehicle battery (DC power supply) 20, and the other end side is connected. It is connected to the negative terminal of the in-vehicle battery 20 via the switch SW1, and both ends of the secondary winding L2 are connected to the output block 14, respectively. The switch SW1 is turned on and off in response to a switching signal (pulse signal) from the microcomputer 18. The transformer T1 stores the input voltage from the in-vehicle battery 20 as electromagnetic energy in the primary winding L1 when the switch SW1 is turned on, and stores the electromagnetic energy stored in the primary winding L1 on the secondary side when the switch SW1 is turned off. To the output block 14.

  As the switch SW1, for example, as shown in FIG. 2, an NMOS transistor 22 as a switching element can be used. As circuit elements for driving the NMOS transistor 22, resistors R11 and R12, an NPN transistor 24, and a PNP transistor are used. 26 is provided. The drain of the NMOS transistor 22 is connected to the primary winding L1 of the transformer T1, and the source is grounded. The bases of the NPN transistor 24 and the PNP transistor 26 are connected to the output terminal 28 of the microcomputer 18 to constitute a buffer circuit. When a high level switching signal is output from the microcomputer 18, the NPN transistor 24 is turned on and the NMOS transistor 22 is turned on so that electromagnetic energy is accumulated in the primary winding L1. . On the other hand, when a low level switching signal is output from the microcomputer 18, the PNP transistor 26 is turned on, the NMOS transistor 22 is turned off, and the electromagnetic energy accumulated in the primary winding L1 is transferred from the secondary side of the transformer T1. It is discharged to the output block 14.

  As shown in FIG. 1, the output block 14 is connected to both ends of the LED 1 with the LED 1 as a load. The output block 14 rectifies electromagnetic energy emitted from the secondary side of the transformer T1 and propagates to the LED 1 as light emission energy. As propagation means, a diode D1 as a rectifying element that rectifies the current output from the secondary side of the transformer T1 and a capacitor C1 that smoothes the output current of the diode D1 are provided. A series circuit of a resistor R1 and LED1 for detecting a current supplied to LED1 (current flowing through LED1) is connected to both ends of the capacitor C1 of the output block 14. For example, the resistor R1 is configured as a current detection unit that converts a current flowing through the resistor R1 into a voltage and outputs the voltage to the multiplexer 16 when one end of the secondary winding L2 of the transformer T1 is grounded.

  The multiplexer 16 includes switches SW100, SW101, and SW102. One end of the switch SW100 is connected to the plus terminal of the in-vehicle battery 20, and the other end is connected to the A / D conversion terminal 30 of the microcomputer 18. The switch SW101 has one end connected to the connection point between the resistor R1 and the LED1, the other end connected to the A / D conversion terminal 30, and the switch SW2 connected to the connection point between the diode D1 and the LED1. The other end side is connected to the A / D conversion terminal 30. The switch SW100 opens and closes the circuit in response to a signal from the input / output terminal (I / O) 32 of the microcomputer 18, and the switch SW101 opens and closes the circuit in response to a signal from the input / output terminal 34. Is configured to open and close the circuit in response to a signal from the input / output terminal 36. The switches SW100 to SW102 are normally turned on in order, so that only a single analog signal among the analog signals input to the switches SW100 to SW102 is output to the A / D conversion terminal 30. It has become.

  That is, the multiplexer 16 is configured as a selection unit that takes in a plurality of analog signals and sequentially selects and outputs a single analog signal from the plurality of taken-in analog signals. And switch SW100 takes in-vehicle battery (DC power supply) 20 as an object of detection, takes in the output voltage of in-vehicle battery 20, that is, the input voltage of switching regulator 12, and uses this input voltage as an analog signal indicating the state quantity of in-vehicle battery 20. The data is output to the A / D conversion terminal 30. The switch SW101 is configured to capture the voltage corresponding to the current flowing through the LED1, targeting the LED1, and output the captured voltage to the A / D conversion terminal 30 as an analog signal indicating the state quantity of the LED1. Further, the switch SW102 detects the voltage applied to the LED1, that is, the output voltage of the output block 14 with the LED1 as a detection target, and outputs the acquired voltage to the A / D conversion terminal 30 as an analog signal indicating the state quantity of the LED1. It is like that.

  The switches SW100 to SW102 are configured using, for example, a PMOS transistor 38, a Zener diode Z1, resistors R13, R14, R15, R16, NPN transistors 40, 42, and a PNP transistor 44 as switching elements, as shown in FIG. can do. The source of the PMOS transistor 38 is connected to the plus terminal of the in-vehicle battery 20 or the connection point between the resistor R1 and the LED1, or the connection point between the diode D1 and the LED1, the drain is connected to the A / D conversion terminal 30, and the gate is The resistor R14 is connected to the collector of the NPN transistor 40. The base of the NPN transistor 40 is connected to the emitter of the NPN transistor 42 and the emitter of the PNP transistor 44 through the resistor R15, and the bases of the NPN transistor 42 and the PNP transistor 44 are connected to the input / output terminals 32, 34, and 36 of the microcomputer 18, respectively. Has been. The NPN transistor 42 and the PNP transistor 44 constitute a buffer circuit. When a high level signal is output from the input / output terminal 32 or 34 or the input / output terminal 36 of the microcomputer 18, the NPN transistor 42 is turned on and the NPN transistor is turned on. As the transistor 40 is turned on and the NPN transistor 40 is turned on, the PMOS transistor 38 is turned on, and an analog signal from the detection target is transmitted to the A / D conversion terminal 30 side.

  On the other hand, when the level of the signal output from the input / output terminal 32 or 34 or the input / output terminal 36 of the microcomputer 18 is inverted to a low level, the PNP transistor 44 is turned on and the NPN transistor 40 is turned off. Is turned off, the PMOS transistor 38 is turned off, and the circuit for transmitting the analog signal is cut off.

  The microcomputer 18 includes a CPU (Central Processing Unit) or a microprocessor, a RAM (Random Access Memory), a ROM (Read Only Memory), an input / output interface, and the like. And a control means for executing calculation processing relating to generation of a switching signal for turning on / off the switch SW1 based on digital data relating to the state quantity of the LED1 and controlling the switch SW1 based on the result of the calculation processing. .

  Furthermore, in this embodiment, the microcomputer 18 monitors the state of the in-vehicle battery 20 and the LED 1 and performs feedback control based on the output voltage and output current of the switching regulator 12 based on the monitoring result, or the switching regulator 12 Control for stopping the operation of the switching regulator 12 based on the input voltage and derating control for reducing the output current of the switching regulator 12 are performed. The microcomputer 18 receives an analog signal obtained from the detection target. An A / D converter is incorporated as an analog / digital conversion means for converting the signal into a digital signal.

  This A / D converter sequentially converts the analog signal input from the multiplexer 16 to the A / D conversion terminal 30 into a digital signal, and the converted digital signal is digital data relating to the state quantity of the in-vehicle battery 20 or the state quantity of the LED 1. Is output to the CPU as digital data. The CPU generates a switching signal based on the digital signal (digital data) converted by the A / D converter, outputs the generated switching signal from the output terminal 28 to the switch SW1, and controls the on / off operation of the switch SW1. It is supposed to be.

  When the analog signal output from the multiplexer 16 is converted into a digital signal, the A / D converter sequentially converts the input analog signal into a digital signal. In this embodiment, the A / D conversion terminal 30 has a CR signal. Considering that a circuit (filter circuit) is connected, even if analog signals from the switches SW100 to SW102 are sequentially input, the input analog signals are not immediately converted into digital signals, but after a certain time has elapsed. It is designed to convert to a digital signal.

  That is, as shown in FIG. 4, when a CR circuit is connected to the A / D conversion terminal 30, switching to select a low potential voltage from a high potential voltage is performed by the capacitance component of the CR circuit. There are periods in which the signal waveform is dull (periods from timing t2 to t3 and periods from timing t4 to t5). For this reason, an analog signal is converted into a digital signal at a timing from timing t3 to t4 or from timing t5 to t6 in a period from timing t3 to t6, avoiding a period in which the signal waveform is dull. Thereby, accurate digital data can be generated from the converted digital signal.

  In addition, when the analog signal input from the multiplexer 16 is sequentially converted into a digital signal by the A / D converter, a change occurs in the detection target, for example, when the input voltage of the switching regulator 12 starts to rise. The detection target in which the change has occurred, that is, processing for selecting many analog signals related to the input voltage of the multiplexer 12 in preference to other analog signals is performed. When such processing is executed, derating control for reducing the current flowing through the switch SW1 can be performed smoothly and efficiently.

  Further, when it becomes necessary to stop the operation of the switching regulator 12, the on-duty of the switching signal for the switch SW1 is made smaller than the previous value or the on-duty of the switching signal is set to 0. The switching regulator 12 can be stopped immediately.

  When the microcomputer 18 adjusts the on-duty of the switching signal, for example, as shown in FIG. 5, when the count value reaches a set value α as a timer counter, the level of the switching signal is changed from “1” to “1”. A timer counter (not shown) for setting to “0” is provided, and a timer counter (not shown) for setting the level of the switching signal from “0” to “1” when the count value reaches the set value β. And starts counting at timing t1 and counts the clock. When the count value reaches the set value α at timing t2 and a compare match occurs, one timer count is reset and the level of the switching signal is set. Set from “1” to “0” and continue counting the clock. The count value is the set value at timing t3. When β, the other timer count is reset, the level of the switching signal is set from “0” to “1”, and clock counting is started again from timing t3. When the time from the timing t1 to the timing t2 is set to the on-duty and this on-duty is reduced, the on-duty can be reduced by reducing the set value α of one timer counter. Conversely, when increasing the on-duty, the on-duty can be increased by increasing the value of the set value α.

  In the present embodiment, only by incorporating a single A / D converter in the microcomputer 18, three analog signals can be converted into digital signals, and a switching signal can be generated based on the converted digital signals. Thus, the configuration can be simplified and the cost can be reduced.

  In addition, according to this embodiment, each semiconductor light source of a vehicle lamp having a plurality of semiconductor light sources emits light with a target light amount in order to satisfy different light distributions or functions such as a head lamp and a tail & stop lamp. In addition, the configuration can be simplified and the cost can be reduced.

  Instead of incorporating an A / D converter in the microcomputer 18, a single A / D converter is provided outside the microcomputer 18, and an analog signal from the multiplexer 16 is input to the A / D converter. Even if it is adopted, it is possible to convert three analog signals into digital signals and generate switching signals based on the converted digital signals, simplifying the configuration and reducing costs. It becomes possible.

  In the present embodiment, the microcomputer 18 controls the switching regulator 12. However, the present invention can also be applied to other switching regulators, and other embodiments will be described below.

  FIG. 6 shows an embodiment when a time-sharing switching regulator 46 is used. The switching regulator 46 includes a transformer T10, a switch SW1 formed of a switching element is connected to the primary winding L1 of the transformer T10, and an output block 48 is connected to each of the secondary windings L21, L22, L23, L24, and L25. 50, 52, 54, and 56 are connected. Each of the output blocks 48 to 56 includes diodes D1, D2, D3, D4, and D5, capacitors C1, C2, C3, C4, and C5, and switches SW21, SW22, SW23, SW24, and SW25 including switching elements. . At both ends of the capacitors C1, C2, C3, C4, and C5, a series circuit of LED1 and a resistor R1, a series circuit of LED2 and a resistor R2, a series circuit of LED3 and a resistor R3, and a series circuit of LED4 and a resistor R4 The series circuit of LED5 and resistance R5 is connected, respectively. The voltages A, B, C, D, E, F, G, H, I, and J across the LEDs 1 to 5 are input to the switches SW101 to SW110 of the multiplexer 58, respectively. The switches SW100 to SW110 have their outputs connected to the A / D conversion terminal 30, respectively. The switches SW100 to SW102 open and close the circuit in response to signals from the input / output terminals 32, 34, and 36, and the switches SW103 to SW103 The SW 110 opens and closes the circuit in response to signals from the input / output terminals 60 to 74.

  That is, the multiplexer 58 selects only a single analog signal from the plurality of analog signals input to the switches SW100 to SW110 and outputs the selected analog signal to the A / D conversion terminal 30. Then, the microcomputer 18 generates a switching signal for on / off control of the switch SW1 and a switching signal for sequentially on / off control of the switches SW21 to SW25 based on the digital signal converted by the A / D converter. A switching signal is output from the output terminal 28 to the switch SW1, and from the output terminals 76 to 84 to the switches SW21 to SW25.

  For example, when controlling the operation of each switch in the current boundary mode, the switch SW1 is turned on, and the input voltage from the in-vehicle battery 20 is accumulated as electromagnetic energy in the primary winding L1, and is accumulated in the primary winding L1. The electromagnetic energy is discharged to any one of the output blocks 48 to 56 when the switch SW1 is turned off. That is, when the switch SW1 is turned off, only one of the switches SW21 to SW25 is turned on to rectify the current as electromagnetic energy emitted from the secondary side of the transformer T10 to emit light energy. Is supplied to any one of the LEDs 1 to 5.

  According to this embodiment, 11 analog signals are converted into digital signals using a single A / D converter, and switching signals are generated according to the converted digital signals. Even if there is an increase, it can be converted into a digital signal by a single A / D converter, the configuration can be simplified, and the cost can be reduced.

  In addition, although the example using the single A / D converter was shown, even if it uses less than 11 A / D converters, the same effect can be acquired.

  FIG. 7 shows an embodiment in which independent switching regulators 86, 88, 90, and 92 are used. The switching regulators 86 to 92 are configured to include transformers T1, T2, T3, and T4, and switches SW1, SW2, SW3, and SW4 by switching elements, and a diode D1 is provided on the secondary side of each of the transformers T1 to T4. Output blocks 94, 96, 98, 100 having D2, D3, D4 and capacitors C1, C2, C3, C4 are connected. Each output block 94-100 is connected to a series circuit of LED1 and resistor R1, a series circuit of LED2 and resistor R2, a series circuit of LED3 and resistor R3, and a series circuit of LED4 and resistor R4. The voltages A to H generated at both ends of each LED1 to LED4 are input to the switches SW101 to SW108 of the multiplexer 102, respectively.

  The microcomputer 18 in this embodiment sequentially converts the analog signal input from the multiplexer 102 into a digital signal, and generates a switching signal for each of the switches SW1 to SW4 independently (individually) based on the converted digital signal. The switching signal is output to the switches SW1 to SW4 via the output terminals 104, 106, 108, 110. Each of the switches SW1 to SW4 is turned on / off in response to a switching signal from the microcomputer 18. When the switches SW1 to SW4 are turned on, the transformers T1 to T4 accumulate the input voltage from the in-vehicle battery 20 as electromagnetic energy in the primary winding, and the electromagnetic energy accumulated in the primary winding is turned off of the switches SW1 to SW4. Sometimes it is discharged from the secondary side to the output blocks 94-100.

  According to the present embodiment, nine analog signals are converted into digital signals using a single A / D converter, and switching signals for the switches SW1 to SW4 are generated based on the converted digital signals. Therefore, even if the number of analog signals is large, it can be converted into a digital signal by a single A / D converter, so that the configuration can be simplified and the cost can be reduced.

  FIG. 8 shows an embodiment in which a forward switching regulator 112 is used. The switching regulator 112 in this embodiment includes a transformer T11 and a switch SW1, and diodes D1 and D2, a coil L1, and a capacitor C1 are connected to the secondary side of the transformer T11. A series circuit of LED1 and resistor R1 is connected to both ends of the capacitor C1. The multiplexer 16 receives a voltage generated at both ends of the LED 1 together with an input voltage input to the switching regulator 112.

  In this embodiment, when the switch SW1 is on, electromagnetic energy is accumulated in the transformer T11, and is discharged to the secondary side of the transformer T11. When the switch SW1 is off, the electromagnetic energy accumulated in the coil L1 is LED1. To be released.

  According to the present embodiment, three analog signals can be converted into digital signals using a single A / D converter, and the configuration can be simplified and the cost can be reduced. Become.

  FIG. 9 shows an embodiment when a flyback switching regulator 114 is used. The switching regulator 114 includes a transformer T12 and a switch SW1, and a diode D1 and a capacitor C1 are connected to the secondary side of the transformer T12. A series circuit of LED1 and resistor R1 is connected to both ends of the capacitor C1. The multiplexer 16 receives the voltage generated at both ends of the LED 1 together with the input voltage of the switching regulator 14.

  In this embodiment, electromagnetic energy is accumulated in the transformer T1 when the switch SW1 is on, and electromagnetic energy accumulated in the transformer T12 is released to the LED 1 when the switch SW1 is off.

  According to the present embodiment, three analog signals can be converted into digital signals using a single A / D converter, and the configuration can be simplified and the cost can be reduced. Become.

  FIG. 10 shows an embodiment when the step-down switching regulator 116 is used. The switching regulator 116 includes a switch SW1, a diode D1, a coil L1, and a capacitor C1. A series circuit of LED1 and resistor R1 is connected to both ends of the capacitor C1. The multiplexer 16 receives a voltage generated at both ends of the LED 1 together with an input voltage of the switching regulator 116.

  In this embodiment, when the switch SW1 is turned on, the input voltage is accumulated as electromagnetic energy in the coil L1, and when the switch SW1 is turned off, the diode D1 is turned on and the electromagnetic wave accumulated in the coil L1. Energy is released to the LED 1.

  According to the present embodiment, three analog signals can be converted into digital signals using a single A / D converter, and the configuration can be simplified and the cost can be reduced. Become.

  FIG. 11 shows an embodiment when a step-up switching regulator 118 is used. The switching regulator 118 includes a coil L1, a switch SW1, a diode D1, and a capacitor C1. A series circuit of LED1 and resistor R1 is connected to both ends of the capacitor C1. The multiplexer 16 receives the voltage generated at both ends of the LED 1 together with the input voltage of the switching regulator 118.

  In this embodiment, when the switch SW1 is turned on, the input voltage is accumulated in the coil L1 as electromagnetic energy, and when the switch SW1 is turned off, the electromagnetic energy accumulated in the coil L1 is superimposed on the input voltage. It is made to discharge | release to LED1.

  According to the present embodiment, three analog signals can be converted into digital signals using a single A / D converter, and the configuration can be simplified and the cost can be reduced. Become.

  In each of the embodiments described above, the microcomputer 18 is used as the control means. However, the control means includes a microcomputer that performs arithmetic processing according to a program, and a dedicated generator that generates a pulse signal in response to a command from the microcomputer. A control IC (Integrated Circuit) can also be used.

It is a circuit block diagram of the lighting control circuit of the vehicle lamp which shows one Example of this invention. It is a circuit block diagram of the switching element which comprises a switch, and its drive circuit. It is a circuit block diagram of the switching element which comprises the switch for multiplexers, and its drive circuit. It is a wave form diagram for demonstrating operation | movement of a multiplexer. It is a wave form diagram for demonstrating the process of the compare match in a microcomputer. It is a circuit block diagram which shows an Example when the switching regulator by a time-sharing system is used. It is a circuit block diagram which shows an Example when the switching regulator by an independent system is used. It is a circuit block diagram which shows an Example when a forward type switching regulator is used. It is a circuit block diagram which shows an Example when a switching regulator of a flyback system is used. It is a circuit block diagram which shows an Example when a pressure | voltage fall type switching regulator is used. It is a circuit block diagram which shows an Example when a step-up type switching regulator is used.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Lighting control circuit of vehicle lamp 12 Switching regulator 14 Output block 16 Multiplexer 18 Microcomputer 20 Car-mounted battery 46, 86-92, 112-118 Switching regulator 58, 102 Multiplexer

Claims (5)

A switching regulator that converts an input voltage from a power source into electromagnetic energy and emits it by turning on and off a switching element connected to a transformer or a coil, and energy that propagates electromagnetic energy emitted from the switching regulator to a semiconductor light source as light emission energy A plurality of analog signals indicating a state quantity of the detection target are captured by using at least one of the propagation means, the power source, and the semiconductor light source, and a single analog signal is sequentially selected from the captured plurality of analog signals. A selection means for selecting and outputting, an analog / digital conversion means for sequentially converting an analog signal output from the selection means into a digital signal, and a switching signal based on the digital signal converted by the analog / digital conversion means And said raw Lighting control circuit for a vehicle lamp comprising a control means for controlling the on-off operation of the switching element in accordance with the switching signal. A plurality of switching regulators that convert the input voltage from the power source into electromagnetic energy and release it by turning on and off the switching elements connected to the transformer or the coil, and a plurality of different types of electromagnetic energy emitted from each switching regulator as light emission energy A plurality of energy propagation means respectively propagating to the semiconductor light source, and at least one of the power source and the plurality of semiconductor light sources as a detection target, and a plurality of analog signals indicating a state quantity of the detection target are captured and captured A selection means for sequentially selecting and outputting a single analog signal from a plurality of analog signals, an analog / digital conversion means for sequentially converting an analog signal output from the selection means into a digital signal, and the analog / digital Converted by conversion means It generates switching signals digital signals based on, lighting control circuit for a vehicle lamp comprising a control means for controlling the on-off operation of the switching element in accordance with a switching signal wherein the generating. A switching regulator that converts an input voltage from a power source into electromagnetic energy by an on / off operation of a switching element connected to a transformer or a coil and emits it, and a plurality of semiconductor light sources different from each other using the electromagnetic energy emitted from the switching regulator as light emission energy A plurality of energy propagation means for propagating to each other, and at least one of the power source and the plurality of semiconductor light sources as a detection target, and a plurality of analog signals indicating a state quantity of the detection target A selection means for sequentially selecting and outputting a single analog signal from analog signals, an analog-digital conversion means for sequentially converting an analog signal output from the selection means into a digital signal, and the analog-digital conversion means Converted digital No. The generates switching signals based on, lighting control circuit for a vehicle lamp comprising a control means for controlling the on-off operation of the switching element in accordance with a switching signal wherein the generating. 4. The lighting control circuit for a vehicular lamp according to claim 1, wherein the analog / digital conversion means converts an analog signal from the selection means into a digital signal after a predetermined time has elapsed. A lighting control circuit for a vehicular lamp characterized by comprising: 5. The lighting control circuit for a vehicle lamp according to claim 1, wherein when the change occurs in the detection target, the selection unit detects the change. A lighting control circuit for a vehicular lamp, wherein the analog signal is selected in preference to other analog signals.

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