JP2010015752A - Lighting-up control device for vehicular lighting fixture - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the number of signals to a lighting-up and lighting-out control means for controlling lighting-up and lighting-out of a plurality of lamp units having different functions and an abnormality determination means for determining abnormality. <P>SOLUTION: Digital signals inputted into signal input terminals 90-98 are inputted into an A/D input terminal 164 after converting them into analog signals with a D/A conversion circuit 68 with 5-bit resolution, digital signals based on output of open detection circuits 42-52 are inputted into an A/D input terminal 192 after converting them into analog signals with a D/A conversion circuit 70 with 6-bit resolution, and digital signals based on output of short-circuit/ground-fault detection circuits 54-64 are inputted into an A/D input terminal 208 and 224 after converting them into analog signals with a D/A conversion circuit 72 and 74 with 3-bit resolution. A microcomputer 76 controls lighting-up and lighting-out of lamp units 12-22 by discriminating voltage of the A/D input terminals 164, 192, 208 and 224, and determines existence of any abnormalities. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a lighting control device for a vehicular lamp, and more particularly to a lighting control device for a vehicular lamp configured to control lighting of a semiconductor light source including 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.

As a lighting control circuit, for example, one in which a plurality of LEDs connected in parallel is connected to a switching regulator and a series regulator is provided for each LED has been proposed (see Patent Document 1). This lighting control circuit controls each LED so that a specified current flows through each LED, and the switching regulator controls the output voltage to each LED to the maximum voltage according to the control state of the series regulator. When the abnormality of the LED is detected, the operation of the switching regulator is stopped.
JP 2006-103477 A (refer to pages 5 to 8 and FIG. 1)

  In the prior art, the control circuit monitors the presence or absence of an abnormality of each LED. When an abnormality occurs in any of the LEDs, for example, an abnormality associated with a ground fault on the cathode side of the LED, the control circuit The operation stops. At this time, as a switching element of each series regulator, the gate voltage of the NMOS transistor connected to the cathode of each LED is taken into the control circuit via the signal line (line), and in the control circuit, It is determined whether or not the voltage has become abnormal.

  In other words, according to the conventional technique, as many control lines as the number of LEDs are required to monitor whether or not each LED is abnormal.

  Further, each LED is used as a lamp having a different function, for example, a low beam lamp, a high beam lamp, a cornering lamp, a clearance lamp, a bending lamp, etc., and each lamp is connected in parallel to a switching regulator via a drive circuit. It is possible to employ a configuration in which signal lines for instructing turning on / off are respectively taken into the control circuit. However, in this configuration, the control circuit can determine the voltage of each signal line, and control the driving of each drive circuit based on the determination result. There are as many signal lines as necessary to instruct turning on / off of each lamp.

  In this case, if a configuration in which the presence or absence of each lamp is monitored by the control circuit is adopted, the number of lamp functions is further required as signal lines for detecting the presence or absence of each lamp.

  In addition, when monitoring the presence or absence of each lamp with the control circuit, in addition to the abnormality associated with the ground fault of each lamp, for example, when a configuration for monitoring the presence or absence of abnormality associated with the opening of each lamp is adopted, As signal lines for monitoring the presence or absence of an abnormality associated with opening, the number of lamp functions is further required. That is, when monitoring the presence or absence of an abnormality in each lamp, the more abnormality types, the more signal lines are required.

  On the other hand, if the control circuit is configured with a microcomputer, the microcomputer requires as many input terminals as the number of signal lines to connect each signal line to the microcomputer. Necessary.

  The present invention has been made in view of the problems of the prior art described above, and an object of the present invention is to provide an on / off control means for controlling on / off of a plurality of lamp units having different functions or an abnormality of a plurality of lamp units having different functions. An object of the present invention is to provide a lighting control device for a vehicular lamp that can reduce the number of signals input to an abnormality determining means for determining the above.

  In order to achieve the above object, in the lighting control device for a vehicle lamp according to claim 1, in the lighting control device for a vehicle lamp that controls lighting of a plurality of lamp units having different functions, the abnormality of each lamp unit is determined. An abnormality detection means for detecting a signal, a digital-analog conversion means for converting a signal of the abnormality detection means into a normal / abnormal binary signal and converting a digital signal of a plurality of bits corresponding to the number of lamp functions into an analog signal, And an abnormality determining means for determining an abnormality of each lamp unit based on the analog-converted signal.

  (Operation) When detecting an abnormality of each lamp unit, the abnormality detection means converts the signal of each lamp unit into a normal / abnormal binary signal and converts a digital signal corresponding to the number of lamp functions into a digital-analog conversion means. The digital signal captured by the digital-analog conversion means is converted into an analog signal with a resolution of a plurality of bits, the converted analog signal is input to the abnormality determination means, and the abnormality determination means converts the input analog signal into Based on this, the abnormality of each lamp unit is determined.

  That is, normal / abnormal binary signals corresponding to the number of lamp units are analogized with a resolution of a plurality of bits without inputting all normal / abnormal binary signals corresponding to the number of lamp units to the abnormality determination means. It is possible to determine the abnormality of each lamp unit simply by converting it into a signal and inputting the converted single analog signal to the abnormality determination means. For this reason, the number of signal inputs to the abnormality determination means can be reduced.

  In the lighting control device for a vehicle lamp according to claim 2, in the lighting control device for a lighting device for a vehicle that controls lighting of a plurality of lamp units having different functions, an on / off signal of the lamp unit transmitted from the outside is turned on / off. A digital-analog conversion means for converting a digital signal of a plurality of bits corresponding to the number of lamp functions into an analog signal as a binary signal for extinction, and lighting / extinguishing of each lamp unit based on the analog-converted signal And a lighting on / off control means.

  (Operation) When controlling the lighting / extinguishing of each lamp unit, the lighting / extinguishing signal of the lamp unit transmitted from the outside is a binary signal for lighting / extinguishing, and a digital-analog as a digital signal corresponding to the number of lamp functions The digital signal captured by the conversion means and converted by the digital-analog conversion means is converted into an analog signal with a resolution of a plurality of bits, the converted analog signal is input to the lighting / light-out control means, and the lighting / light-out control means is input. On / off control of each lamp unit is controlled based on the analog signal.

  That is, without turning on / off all the lighting signals corresponding to the number of lamp functions to the lighting control means, the lighting signals corresponding to the number of lamp functions are converted into analog signals with a multi-bit resolution. Further, it is possible to control turning on / off of each lamp unit only by inputting a single analog signal to the turning on / off control means. For this reason, the number of signal inputs to the lighting on / off control means can be reduced.

  In the vehicle lamp lighting control device according to claim 3, in the vehicle lamp lighting control device according to claim 1, as the abnormality detecting means, the abnormality of each lamp unit is detected by classifying the abnormality. A plurality of abnormality detection means, and as the digital-analog conversion means, a plurality of digital-analog conversion means for converting digital signals output from the plurality of abnormality detection means into analog signals, respectively, the abnormality determination means, Based on the output signals of the plurality of digital-analog conversion means, the abnormality of each lamp unit is determined according to its type.

  (Operation) When determining the abnormality of each lamp unit, a plurality of abnormality detection means are provided according to the type of abnormality of each lamp unit, and the digital signal output from each abnormality detection means is respectively converted into a plurality of digital-analog conversion means. Convert to analog signal, input the converted analog signal to each lighting / extinguishing control means, and the lighting / extinguishing control means determines the abnormality of each lamp unit according to its type based on each inputted analog signal It is said.

  That is, the normal / abnormal binary signal corresponding to the number of each lamp unit is not input to the abnormality determining means for all types of abnormality, and the normal / abnormal binary signal corresponding to the number of each lamp unit is input. By converting the analog signal into multi-bit resolution for each abnormality type and inputting the converted analog signal to the abnormality determining means for each abnormality type, the abnormality of each lamp unit is determined according to the type. be able to. For this reason, even when the abnormality of each lamp unit is detected in a plurality of types, the number of signal inputs to the abnormality determination means can be reduced.

  Further, by adopting a configuration in which a plurality of digital-analog conversion means are provided according to the type of abnormality of each lamp unit, and an analog signal converted by each digital-analog conversion means is respectively input to the abnormality determination means. Different types of abnormalities can be determined more accurately than when digital signals relating to a plurality of types of abnormalities are converted into analog signals by a single digital-analog conversion means.

  According to the lighting control device for a vehicle lamp according to the first aspect, the number of signal inputs to the abnormality determination means can be reduced, which can contribute to cost reduction.

  According to the lighting control device for a vehicular lamp according to the second aspect, the number of signal inputs to the on / off control means can be reduced, which can contribute to cost reduction.

  According to the lighting control device for a vehicular lamp according to the third aspect, the number of signal inputs to the abnormality determination means can be reduced even when the abnormality of each lamp unit is detected in a plurality of types.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a light emitting device for a vehicle showing an embodiment of the present invention, and FIG. 2 is a circuit diagram of a D / A conversion circuit.

  In FIG. 1, a vehicle light emitting device 10 constituting a vehicle lamp includes a plurality of lamp units 12 to 22 and a lighting control device 24 for a vehicle lamp that controls lighting of the lamp units 12 to 22.

  The lamp units 12 to 22 are composed of, for example, LEDs 1 to 6 as semiconductor light sources. LED1 to LED6 are configured as lamp units having different functions. For example, LED1 configures a # 1 low beam lamp unit (Low1) 12 and LED2 configures a # 2 low bibee lamp unit (Low2) 14. LED 3 constitutes a high beam lamp unit (High) 16, LED 4 constitutes a DRL (Daytime Running Lamp) lamp unit 18, and LED 5 constitutes a CL (Cornering Lamp) lamp unit 20, The LED 6 constitutes a turn signal lamp (TURN) lamp unit 22.

  The LEDs 1 to 6 used for the lamp units 12 to 22 are not limited to a single one, but a plurality of units connected in series with each other, or a plurality of units connected in series with each other as a light source block, It is also possible to use a plurality of light source blocks connected in parallel. Further, as the lamp unit, CLL (Clearance Lamp), FOG (Fog Lamp), BL (Bending Lamp), or the like can be used.

  The lighting control device 24 for a vehicular lamp includes a switch circuit 26, a switching regulator 28, current drive circuits 30 to 40, an open detection circuit 42 to 52, a short circuit / ground fault detection circuit 54 to 64, a protection circuit 66, a D / A ( Digital / Analog) conversion circuits 68 to 74 and a microcomputer 76 are provided. The microcomputer 76 includes, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a micro that includes an input / output interface, and the like. Consists of a computer.

  The switch circuit 26 includes a PMOS transistor 78, an NPN transistor 80, diodes D1 to D5, a Zener diode ZD1, and resistors R1 to R5. D6 is a parasitic diode of the PMOS transistor 78.

  The PMOS transistor 78 is configured as a switching element that executes a switching operation, and the source is connected to the plus terminal of the in-vehicle battery (DC power supply) 86 via the power supply terminal 82 and the power supply switch 84, and the drain is connected to the switching regulator 28. ing. Between the source and gate of the PMOS transistor 78, a Zener diode ZD1 for securing a withstand voltage is connected in parallel.

  The NPN transistor 80 has a collector connected to the gate of the PMOS transistor 78 via the resistor R4, a base connected to the cathodes of the diodes D1 to D5 via the resistors R2 and R1, respectively, and an emitter mounted on the vehicle via the power supply terminal 88. The battery 86 is connected to the negative terminal and grounded.

  The diodes D1 to D5 constitute an OR circuit, and the anodes of the diodes D1 to D5 are connected to the signal input terminals 90 to 98, respectively. The signal input terminals 90 to 98 are signals transmitted from an external electronic control unit (ECU), for example, a turn-on / off signal instructing to turn on or off the lamp units 12 to 22 is a binary signal (digital) Signal).

  For example, when the lamp units (LOW1, 2) 12, 14 are turned on, a high level signal is input to the signal input terminal 90 as a lighting signal that instructs the lamp units 12, 14 to turn on. When the light is turned off, a low level signal is input as a turn-off signal that instructs the lamp units 12 and 14 to turn off.

  A high level signal is input to the signal input terminal 92 as a lighting signal for instructing lighting of the lamp unit 16 when the lamp unit (High) 16 is turned on. When the lamp unit 16 is turned off, the lamp unit 16 is turned off. A low level signal is input as a turn-off signal for instructing.

  Similarly, when the lamp unit (DRL) 18 is turned on, a high level signal is input to the signal input terminal 94 as a lighting signal for instructing lighting of the lamp unit 18, and when the lamp unit 18 is turned off, A low level signal is input as an extinguishing signal for instructing extinction.

  Similarly, when the lamp unit (CL) 20 is lit, a high level signal is input to the signal input terminal 96 as a lighting signal for instructing the lighting of the lamp unit 20, and when the lamp unit 20 is turned off, A low level signal is input as an extinguishing signal for instructing extinction.

  Similarly, when the lamp unit (TURN) 22 is turned on, a high level signal is input to the signal input terminal 98 as a lighting signal for instructing lighting of the lamp unit 22, and when the lamp unit 22 is turned off, A low level signal is input as an extinguishing signal for instructing extinction.

  When a high level signal is input to any one of the signal input terminals 90 to 98 and the power switch 84 is turned on, any one of the diodes D1 to D5 is conducted and the NPN transistor 80 is turned on. When the NPN transistor 80 is turned on, the gate of the PMOS transistor 78 is grounded via the NPN transistor 80 and the resistor R4, and the PMOS transistor 78 is turned on. When the PMOS transistor 78 is turned on, DC power (DC current) from the in-vehicle battery 86 is supplied to the switching regulator 28 via the PMOS transistor 78.

  The switching regulator 28 includes NMOS transistors 100 and 102, a control circuit 104, a transformer T1, and capacitors C1 and C2. The diode D7 is a parasitic diode of the NMOS transistor 102. A capacitor C1 is connected in parallel to the primary side of the transformer T1, and an NMOS transistor 100 is connected in series. A capacitor C2 is connected in parallel to the secondary side of the transformer T1, and an NMOS transistor 102 is connected in series. The gates of the NMOS transistors 100 and 102 are connected to the control circuit 104, respectively.

  When receiving an ON signal from the control signal terminal 105 of the microcomputer 76, the control circuit 104 generates a switching signal and outputs the generated switching signal to the gates of the NMOS transistors 100 and 102. When the NMOS transistor 100 is turned on in response to the switching signal, a direct current from the PMOS transistor 78 flows to the primary side of the transformer T1, and electromagnetic energy is accumulated on the primary side of the transformer T1.

  On the other hand, when the NMOS transistor 100 is turned off in response to the switching signal, the electromagnetic energy accumulated on the primary side of the transformer T1 is released to the secondary side of the transformer T1. At this time, when the NMOS transistor 102 is turned on in response to the switching signal, a direct current is supplied to the current driving circuits 30 to 40 from the secondary side of the transformer T1.

  The current driving circuits 30 to 40 have an input side connected in parallel to the output side of the switching regulator 28, and an output side connected to both ends of the lamp units 12 to 22 via output terminals 118 to 140.

  The current drive circuits 30 to 40 include switching elements, for example, NMOS transistors (not shown) that are turned on under the condition that the on signals are received from the control signal terminals 106 to 116 of the microcomputer 76. A specified current is supplied to each of the lamp units 12 to 22, and the lamp units 12 to 22 are turned on.

  At this time, the presence or absence of abnormality of the lamp units 12 to 22 is monitored by the open detection circuits 42 to 52 and the short circuit / ground fault detection circuits 54 to 64.

  The open detection circuits 42 to 52 detect whether or not the lamp units 12 to 22 are in an open state as an abnormality of the lamp units 12 to 22. As a result of this detection, a normal / abnormal binary signal (digital signal) is detected. Is configured as first abnormality detection means for outputting.

  Specifically, in the open detection circuits 42 to 52, the output terminals 118, 120, 122, 124, 126, 128, 130, 132, 134, 136, 138, and 140 of the current drive circuits 30 to 40 are open (open). When it is detected that the LED 1 or 6 has become open, or when it is detected that the LEDs 1 to 6 have an open failure, a high level signal is output to the D / A conversion circuit 70, and otherwise (the lamp unit When 12 to 22 are in a normal state), a low level signal is output to the D / A conversion circuit 70.

  On the other hand, the short circuit / ground fault detection circuits 54 to 58 detect whether or not the lamp units 12 to 16 are short-circuited or grounded as an abnormality of the lamp units 12 to 16. The second abnormality detection means is configured to output a value signal (digital signal).

  Specifically, the short-circuit / ground fault detection circuits 54 to 58 connect the LED 1 to LED 3 with both ends short-circuited, or connect the output terminals 118, 122, and 126 of the current drive circuits 30 to 40 to the anodes of the LEDs 1 to LED 3. When it is detected that the line has a ground fault, a high level signal is output to the D / A conversion circuit 72, and at other times (when the lamp units 12 to 16 are in a normal state), a low level signal is output. Is output to the D / A conversion circuit 72.

  Further, the short-circuit / ground fault detection circuits 60 to 64 detect whether or not the lamp units 18 to 22 are short-circuited or ground-faulted as an abnormality of the lamp units 18 to 22, and as a result of this detection, normal / abnormal 2 This is configured as third abnormality detection means for outputting a value signal (digital signal).

  Specifically, in the short-circuit / ground fault detection circuits 60 to 64, both ends of the LEDs 4 to 6 are short-circuited, or the output terminals 130, 134, and 138 of the current drive circuits 30 to 40 are connected to the anodes of the LEDs 4 to LED6. When it is detected that the line has a ground fault, a high level signal is output to the D / A conversion circuit 74, and at other times (when the lamp units 18 to 22 are in a normal state), a low level signal is output. Is output to the D / A conversion circuit 74.

  The D / A conversion circuits 70 to 74, together with the D / A conversion circuit 68, are configured as digital-analog conversion means for converting a multi-bit digital signal corresponding to the number of lamp functions into an analog signal. A digital lighting signal is input to the conversion circuit 68 from the signal input terminals 90 to 98 via the protection circuit 66.

  The protection circuit 66 includes resistors R6 to R10 and diodes D8 to D17, and the resistors R6 to R10 are inserted in series between the input side of the D / A conversion circuit 68 and the signal input terminals 90 to 98. The diodes D8 to D12 and the diodes D13 to D17 are connected in series, and each series connection point is connected to the input side of the D / A conversion circuit 68.

  In the protection circuit 66, when a voltage (positive voltage) higher than the set voltage is applied to any of the signal input terminals 90 to 98, any of the diodes D8 to D12 becomes conductive, and the D / A conversion circuit 68 An abnormal voltage is prevented from being applied to the input side. In addition, when a voltage lower than the set voltage (negative voltage) is applied to any of the signal input terminals 90 to 98, the protection circuit 66 conducts any of the diodes D13 to D17, and the D / A conversion circuit An abnormal voltage is prevented from being applied to the input side of 68. The signal input terminals 90 to 98 can be directly connected to the input side of the D / A conversion circuit 68 without using the protection circuit 66.

  As shown in FIG. 2A, the D / A conversion circuit 68 includes resistors R11 to R35 and NPN transistors 142 to 150, and is a multi-bit digital corresponding to the number of the plurality of lamp units 12 to 22 having different functions. It is configured as a digital-analog converting means for converting five types of lighting / lighting signals transmitted from an external electronic control unit into analog signals with a resolution of 5 bits.

  One ends of the resistors R11 to R15 are connected to the input terminals 152 to 160, respectively, and the connection points between the resistors R11 to R15 and the resistors R16 to R20 are connected to the bases of the NPN transistors 142 to 150. The input terminals 152 to 160 are connected to the signal input terminals 90 to 98 via the resistors R6 to R10 of the protection circuit 66.

  One ends of the resistors R21 to R25 are connected to the reference voltage Vref, and connection points of the resistors R21 to R25 and the resistors R26 to R30 are connected to collectors of the NPN transistors 142 to 150. The resistors R31 to R35 are connected in series to form a ladder circuit of “R-2R” together with the resistors R26 to R30, and one end side of the resistor R31 is connected to the A / D input terminal 164 of the microcomputer 76 via the output terminal 162. And one end of the resistor R35 is grounded.

  When the resistance values of the resistors R31 to R34 are "R" as the resistance values of the resistors R26 to R30 and the resistors R31 to R35 constituting the ladder circuit of "R-2R", the resistances of the resistors R26 to R30 and the resistor R35 The value is set to “2R”. In this case, the voltage error during D / A conversion can be reduced by making the resistance values of the resistors R21 to R25 sufficiently smaller than “R”.

  Here, when the high-level lighting signal input to the signal input terminal 90 is input to the input terminal 152 of the D / A conversion circuit 68 via the protection circuit 66, the NPN transistor 142 is turned on, and the D / A A voltage of 15/32 Vref is output from the output terminal 162 of the A conversion circuit 68.

  When a high level lighting signal input to the signal input terminal 92 is input to the input terminal 154 of the D / A conversion circuit 68 via the protection circuit 66, the NPN transistor 144 is turned on, and the D / A A voltage of 23/32 Vref is output from the output terminal 162 of the conversion circuit 68.

  Similarly, when a high-level lighting signal input to the signal input terminal 94 is input to the input terminal 156 of the D / A conversion circuit 68 via the protection circuit 66, the NPN transistor 146 is turned on, and the D / A A voltage of 27/32 Vref is output from the output terminal 162 of the A conversion circuit 68.

  Similarly, when a high-level lighting signal input to the signal input terminal 96 is input to the input terminal 158 of the D / A conversion circuit 68 via the protection circuit 66, the NPN transistor 148 is turned on, and the D / A A voltage of 29/32 Vref is output from the output terminal 162 of the A conversion circuit 68.

  Similarly, when a high-level lighting signal input to the signal input terminal 98 is input to the input terminal 160 of the D / A conversion circuit 68 via the protection circuit 66, the NPN transistor 150 is turned on, and the D / A A voltage of 30/32 Vref is output from the output terminal 162 of the A conversion circuit 68.

  That is, when high level lighting signals are sequentially input to the input terminals 152 to 160, the D / A conversion circuit 68 divides the reference voltage Vref with 5-bit resolution in response to the high level lighting signals. The pressed voltages 15/32 Vref, 23/32 Vref, 27/32 Vref, 29/32 Vref, and 30/32 Vref can be sequentially output from the output terminal 162 to the A / D input terminal 164 of the microcomputer 76.

  At this time, the microcomputer 76 converts the voltage input to the A / D input terminal 164 into a digital signal by the A / D conversion unit, and controls turning on / off of each lamp unit 12 to 22 based on the converted digital signal. It functions as an on / off control means.

  For example, when a voltage of 15/32 Vref is input to the A / D input terminal 164, the microcomputer 76 receives a lighting signal (lighting instruction information) for instructing lighting of the lamp units (Low 1, 2) 12, 14. The control signal terminals 105, 106, 108 output an ON signal to operate the switching regulator 28, operate the current drive circuits 30, 32, and turn on the lamp units (Low 1, 2) 12, 14. .

  Further, the microcomputer 76 determines that when a voltage of 23/32 Vref is input to the A / D input terminal 164, a lighting signal (lighting instruction information) instructing lighting of the lamp unit (High) 16 is input, An ON signal is output from the control signal terminals 105 and 110, the switching regulator 28 is operated, the current drive circuit 34 is operated, and the lamp unit (High) 16 is turned on.

  Similarly, when a voltage of 27/32 Vref is input to the A / D input terminal 164, the microcomputer 76 determines that a lighting signal (lighting instruction information) for instructing lighting of the lamp unit (DRL) 18 is input. The ON signal is output from the control signal terminals 105 and 112, the switching regulator 28 is operated, the current driving circuit 36 is operated, and the lamp unit (DRL) 18 is turned on.

  Similarly, when the voltage of 29/32 Vref is input to the A / D input terminal 164, the microcomputer 76 determines that a lighting signal (lighting instruction information) for instructing lighting of the lamp unit (CL) 20 is input. The ON signal is output from the control signal terminals 105 and 114, the switching regulator 28 is operated, the current driving circuit 38 is operated, and the lamp unit (CL) 20 is turned on.

  Similarly, the microcomputer 76 determines that a lighting signal (lighting instruction information) for instructing lighting of the lamp unit (TURN) 22 is input to the A / D input terminal 164 when a voltage of 30/32 Vref is input. Then, an ON signal is output from the control signal terminals 105 and 116, the switching regulator 28 is operated, the current driving circuit 40 is operated, and the lamp unit (TURN) 22 is turned on.

  When a high-level lighting signal is input to a plurality of input terminals 152 to 160, a voltage corresponding to the number of NPN transistors turned on among the NPN transistors 142 to 150 is output from the output terminal 162. Is done. For this reason, the microcomputer 76 identifies the level of the voltage input to the A / D input terminal 164 to simultaneously turn on a plurality of lamp units having different functions, for example, the lamp units 12 and 14 and the lamp unit 22. Can do.

  As shown in FIG. 2B, the D / A conversion circuit 70 includes resistors R41 to R70 and NPN transistors 166 to 176, and is a multi-bit digital corresponding to the number of the plurality of lamp units 12 to 22 having different functions. It is configured as a digital-analog conversion means for converting six open detection signals output from the open detection circuits 42 to 52 into analog signals with 6-bit resolution.

  One ends of the resistors R41 to R46 are connected to the input terminals 178 to 188, respectively, and the connection points of the resistors R41 to R46 and the resistors R47 to R52 are connected to the bases of the NPN transistors 166 to 176. The input terminals 178 to 188 are connected to the output terminals of the open detection circuits 42 to 52.

  One ends of the resistors R53 to R58 are connected to the reference voltage Vref, and a connection point between the resistors R53 to R58 and the resistors R59 to R64 is connected to the collectors of the NPN transistors 166 to 176. The resistors R65 to R70 are connected in series to form a ladder circuit of “R-2R” together with the resistors R59 to R64, and one end side of the resistor R65 is connected to the A / D input terminal 192 of the microcomputer 76 via the output terminal 190. And one end of the resistor R70 is grounded.

  When the resistance values of the resistors R65 to R69 and the resistance values of the resistors R65 to R69 are “R” as the resistance values of the resistors R59 to R64 and the resistors R65 to R70 constituting the ladder circuit “R-2R”, The value is set to “2R”. In this case, the voltage error during D / A conversion can be reduced by making the resistance values of the resistors R53 to R58 sufficiently smaller than “R”.

  Here, when a high level signal (open detection signal) is input from the open detection circuit 42 to the input terminal 178, the NPN transistor 166 is turned on, and from the output terminal 190 of the D / A conversion circuit 70, 31 / A voltage of 64 Vref is output.

  Further, when a high level signal (open detection signal) is input from the open detection circuit 44 to the input terminal 180, the NPN transistor 168 is turned on, and the output terminal 190 of the D / A conversion circuit 70 receives 47/64 Vref. Is output.

  Similarly, when a high level signal (open detection signal) is input from the open detection circuit 46 to the input terminal 182, the NPN transistor 170 is turned on, and the output terminal 190 of the D / A conversion circuit 70 receives 55 / A voltage of 64 Vref is output.

  Similarly, when a high-level signal (open detection signal) is input from the open detection circuit 48 to the input terminal 184, the NPN transistor 172 is turned on, and the output terminal 190 of the D / A conversion circuit 70 receives 59 / A voltage of 64 Vref is output.

  Similarly, when a high level signal (open detection signal) is input from the open detection circuit 50 to the input terminal 186, the NPN transistor 174 is turned on, and the output terminal 190 of the D / A conversion circuit 70 receives 61 / A voltage of 64 Vref is output.

  Similarly, when a high-level signal (open detection signal) is input from the open detection circuit 52 to the input terminal 188, the NPN transistor 176 is turned on, and the output terminal 190 of the D / A conversion circuit 70 receives 62 / A voltage of 64 Vref is output.

  That is, when high level signals are sequentially input to the input terminals 178 to 188, the D / A conversion circuit 70 divides the reference voltage Vref with 6-bit resolution in response to each high level signal. The voltages 31/64 Vref, 47/64 Vref, 55/64 Vref, 59/64 Vref, 61/64 Vref, and 62/64 Vref can be sequentially output from the output terminal 190 to the A / D input terminal 192 of the microcomputer 76.

  At this time, the microcomputer 76 converts the voltage input to the A / D input terminal 192 into a digital signal by the A / D converter, and opens it in any of the lamp units 12 to 22 based on the converted digital signal. It functions as an abnormality determination means for determining that an accompanying abnormality has occurred.

  For example, when a voltage of 31/64 Vref is input to the A / D input terminal 192, the microcomputer 76 determines that an abnormality due to opening has occurred in the lamp unit (Low 1) 12, and turns off the control signal terminal 106. Is output, and the operation of the current driving circuit 30 is stopped.

  Further, when a voltage of 47/64 Vref is input to the A / D input terminal 192, the microcomputer 76 determines that an abnormality due to opening has occurred in the lamp unit (Low2) 14, and the control signal terminal 108 outputs an off signal. Is output, and the operation of the current drive circuit 32 is stopped.

  Similarly, when a voltage of 55/64 Vref is input to the A / D input terminal 192, the microcomputer 76 determines that an abnormality due to opening has occurred in the lamp unit (High) 16, and turns off from the control signal terminal 110. A signal is output, and the operation of the current drive circuit 34 is stopped.

  Similarly, when a voltage of 59/64 Vref is input to the A / D input terminal 192, the microcomputer 76 determines that an abnormality due to opening has occurred in the lamp unit (DRL) 18, and turns off from the control signal terminal 112. A signal is output, and the operation of the current drive circuit 36 is stopped.

  Similarly, when a voltage of 61/64 Vref is input to the A / D input terminal 192, the microcomputer 76 determines that an abnormality due to opening has occurred in the lamp unit (CL) 20, and turns off from the control signal terminal 114. A signal is output, and the operation of the current drive circuit 38 is stopped.

  Similarly, when a voltage of 62/64 Vref is input to the A / D input terminal 192, the microcomputer 76 determines that an abnormality due to opening has occurred in the lamp unit (TURN) 22 and turns off from the control signal terminal 116. A signal is output and the operation of the current drive circuit 40 is stopped.

  When a high level signal is input to a plurality of input terminals 178 to 188, a voltage corresponding to the number of NPN transistors turned on among the NPN transistors 166 to 176 is output from the output terminal 190. The For this reason, the microcomputer 76 discriminates the voltage input to the A / D input terminal 192, so that a plurality of lamp units having different functions, for example, the lamp unit 12 and the lamp unit 22 have abnormality caused by opening simultaneously. Can be determined.

  As shown in FIG. 2C, the D / A conversion circuit 72 includes resistors R71 to R85 and NPN transistors 194 to 198, and is a multi-bit digital corresponding to the number of the plurality of lamp units 12 to 16 having different functions. The signal is configured as a digital-analog converting means for converting three short-circuit / ground fault detection signals output from the short-circuit / ground fault detection circuits 54 to 58 into analog signals with a resolution of 3 bits.

  One ends of the resistors R71 to R73 are connected to the input terminals 200 to 204, respectively, and the connection points between the resistors R71 to R73 and the resistors R74 to R76 are connected to the bases of the NPN transistors 194 to 198. The input terminals 200 to 204 are connected to output terminals of the short circuit / ground fault detection circuits 54 to 58.

  One ends of the resistors R77 to R79 are connected to the reference voltage Vref, and a connection point between the resistors R77 to R79 and the resistors R80 to R82 is connected to collectors of the NPN transistors 194 to 198. The resistors R83 to R85 are connected in series with each other to form an “R-2R” ladder circuit together with the resistors R80 to R82. One end of the resistor R83 is connected to the A / D input terminal 208 of the microcomputer 76 via the output terminal 206. And one end of the resistor R85 is grounded.

  When the resistance values of the resistors R83 and R84 are "R" as the resistance values of the resistors R80 to R82 and the resistors R83 to R85 that constitute the ladder circuit of "R-2R", the resistances of the resistors R80 to R82 and the resistor R85 The value is set to “2R”. In this case, the voltage error at the time of D / A conversion can be reduced by making the resistance values of the resistors R77 to R79 sufficiently smaller than “R”.

  Here, when a high level signal (short circuit / ground fault detection signal) is input from the short circuit / ground fault detection circuit 54 to the input terminal 200, the NPN transistor 194 is turned on, and the output terminal of the D / A conversion circuit 72. From 206, a voltage of 3/8 Vref is output.

When a high level signal (short circuit / ground fault detection signal) is input from the short circuit / ground fault detection circuit 56 to the input terminal 202, the NPN transistor 196 is turned on, and the output terminal 206 of the D / A conversion circuit 72 is turned on. Outputs a voltage of 5/8 Vref.
Similarly, when a high level signal (short circuit / ground fault detection signal) is input from the short circuit / ground fault detection circuit 58 to the input terminal 204, the NPN transistor 198 is turned on, and the output terminal of the D / A conversion circuit 72 is turned on. From 206, a voltage of 6/8 Vref is output.

  That is, when high level signals are sequentially input to the input terminals 200 to 204, the D / A conversion circuit 72 divides the reference voltage Vref with 3-bit resolution in response to each high level signal. The voltages 3/8 Vref, 5/8 Vref, and 6/8 Vref can be sequentially output from the output terminal 206 to the A / D input terminal 208 of the microcomputer 76.

  At this time, the microcomputer 76 converts the voltage input to the A / D input terminal 208 into a digital signal by the A / D conversion unit, and short-circuits in any of the lamp units 12 to 16 based on the converted digital signal. It functions as an abnormality determination means for determining that an abnormality due to a ground fault has occurred.

  For example, when a voltage of 3/8 Vref is input to the A / D input terminal 208, the microcomputer 76 determines that an abnormality due to a short circuit / ground fault has occurred in the lamp unit (Low1) 12, and the control signal terminal 106 An off signal is output from the current driving circuit 30 to stop the operation of the current driving circuit 30.

  Further, when a voltage of 5/8 Vref is input to the A / D input terminal 208, the microcomputer 76 determines that an abnormality due to a short circuit / ground fault has occurred in the lamp unit (Low 2) 14, and the control signal terminal 108 An off signal is output from the current driving circuit 32 to stop the operation of the current driving circuit 32.

  Similarly, when a voltage of 6/8 Vref is input to the A / D input terminal 208, the microcomputer 76 determines that an abnormality due to a short circuit / ground fault has occurred in the lamp unit (High) 16, and the control signal terminal An off signal is output from 110, and the operation of the current drive circuit 34 is stopped.

  When a high level signal is input to a plurality of input terminals 200 to 204, a voltage corresponding to the number of NPN transistors turned on among NPN transistors 194 to 198 is output from the output terminal 206. The For this reason, the microcomputer 76 identifies the level of the voltage input to the A / D input terminal 208, so that a plurality of lamp units having different functions, for example, the lamp unit 12 and the lamp unit 16 are simultaneously short-circuited or grounded. It can be determined that an accompanying abnormality has occurred.

  As shown in FIG. 2D, the D / A conversion circuit 74 includes resistors R91 to R105 and NPN transistors 210 to 214, and is a multi-bit digital corresponding to the number of the plurality of lamp units 20 to 22 having different functions. The signal is configured as a digital-analog conversion means for converting three short-circuit / ground fault detection signals output from the short-circuit / ground fault detection circuits 60 to 64 into analog signals with a resolution of 3 bits.

  One ends of the resistors R91 to R93 are connected to the input terminals 216 to 220, respectively, and a connection point between the resistors R91 to R93 and the resistors R94 to R96 is connected to the bases of the NPN transistors 210 to 214. The input terminals 216 to 220 are connected to output terminals of the short circuit / ground fault detection circuits 60 to 64.

  One ends of the resistors R97 to R99 are connected to the reference voltage Vref, and a connection point between the resistors R97 to R99 and the resistors R100 to R102 is connected to the collectors of the NPN transistors 210 to 214. The resistors R103 to R105 are connected to each other in series to form an “R-2R” ladder circuit together with the resistors R100 to R102. One end of the resistor R103 is connected to the A / D input terminal 224 of the microcomputer 76 via the output terminal 222. And one end of the resistor R105 is grounded.

  When the resistance values of the resistors R103 and R104 are “R” as the resistance values of the resistors R100 to R102 and the resistors R103 to R105 constituting the ladder circuit of “R-2R”, the resistances of the resistors R100 to R102 and the resistor R105 The value is set to “2R”. In this case, the voltage error during D / A conversion can be reduced by making the resistance values of the resistors R97 to R99 sufficiently smaller than “R”.

  Here, when a high level signal (short circuit / ground fault detection signal) is input from the short circuit / ground fault detection circuit 60 to the input terminal 216, the NPN transistor 210 is turned on, and the output terminal of the D / A conversion circuit 72. A voltage of 3/8 Vref is output from 222.

  When a high level signal (short circuit / ground fault detection signal) is input from the short circuit / ground fault detection circuit 62 to the input terminal 218, the NPN transistor 212 is turned on, and the output terminal 222 of the D / A conversion circuit 72. Outputs a voltage of 5/8 Vref.

  Similarly, when a high level signal (short circuit / ground fault detection signal) is input from the short circuit / ground fault detection circuit 64 to the input terminal 220, the NPN transistor 214 is turned on, and the output terminal of the D / A conversion circuit 72 is turned on. A voltage of 6/8 Vref is output from 222.

  That is, when high level signals are sequentially input to the input terminals 216 to 220, the D / A conversion circuit 74 divides the reference voltage Vref with 3-bit resolution in response to each high level signal. The voltages 3/8 Vref, 5/8 Vref, and 6/8 Vref can be sequentially output from the output terminal 222 to the A / D input terminal 224 of the microcomputer 76.

  At this time, the microcomputer 76 converts the voltage input to the A / D input terminal 224 into a digital signal by the A / D conversion unit, and short-circuits in any of the lamp units 18 to 22 based on the converted digital signal. It functions as an abnormality determination means for determining that an abnormality due to a ground fault has occurred.

  For example, when a voltage of 3/8 Vref is input to the A / D input terminal 224, the microcomputer 76 determines that an abnormality due to a short circuit / ground fault has occurred in the lamp unit (DRL) 18, and the control signal terminal 110 An off signal is output from the current driving circuit 36 to stop the operation of the current driving circuit 36.

  Further, when a voltage of 5/8 Vref is input to the A / D input terminal 224, the microcomputer 76 determines that an abnormality due to a short circuit / ground fault has occurred in the lamp unit (CL) 20, and the control signal terminal 114 An off signal is output from the current driving circuit 38 to stop the operation of the current driving circuit 38.

  Similarly, when a voltage of 6/8 Vref is input to the A / D input terminal 224, the microcomputer 76 determines that an abnormality due to a short circuit / ground fault has occurred in the lamp unit (TURN) 22, and the control signal terminal An off signal is output from 116, and the operation of the current drive circuit 40 is stopped.

  When a high level signal is input to a plurality of input terminals 216 to 220, a voltage corresponding to the number of NPN transistors turned on among the NPN transistors 210 to 214 is output from the output terminal 222. The For this reason, the microcomputer 76 identifies the level of the voltage input to the A / D input terminal 224, so that a plurality of lamp units having different functions, for example, the lamp unit 18 and the lamp unit 22 are simultaneously short-circuited or grounded. It can be determined that an accompanying abnormality has occurred.

  In this embodiment, when controlling the lighting of the lamp units 12 to 22, the digital instruction signal for instructing the lighting of the lamp units 12 to 22 is analogized by a D / A conversion circuit 68 having a 5-bit resolution. The signal is converted into a signal, the converted analog signal is input to the A / D input terminal 164 of the microcomputer 76, the microcomputer 76 determines the level of the voltage input to the A / D input terminal 164, and the ramp is determined according to the determination result. The lighting on / off of the units 12 to 22 can be controlled.

  When controlling the lighting of the lamp units 12 to 22, communication is performed between the microcomputer 76 and the electronic control unit via the communication terminals 226 and 228, and the microcomputer 76 performs communication contents (instructions) from the electronic control unit. Information) can be identified, and the lighting and extinguishing of the lamp units 12 to 22 can be controlled according to the identification result.

  In this embodiment, when determining the abnormality of the lamp units 12 to 22, the digital open detection signal generated by the outputs of the open detection circuits 42 to 52 is converted by the D / A conversion circuit 70 having 6-bit resolution. The lamp unit is converted into an analog signal, the converted analog signal is input to the A / D input terminal 192 of the microcomputer 76, and the microcomputer 76 determines the level of the voltage input to the A / D input terminal 192. It can be determined that any of 12 to 22 is abnormal due to opening.

  Further, in this embodiment, when the abnormality of the lamp units 12 to 22 is determined, the digital short circuit / ground fault detection is performed by the outputs of the short circuit / ground fault detection circuits 54 to 58 or the short circuit / ground fault detection circuits 60 to 64. The signal is converted into an analog signal by a D / A conversion circuit 72 or a D / A conversion circuit 74 having a resolution of 3 bits, and the converted analog signal is converted into an A / D input terminal 208 or an A / D input terminal of the microcomputer 76. When the microcomputer 76 determines the level of the voltage input to the A / D input terminal 208 or the A / D input terminal 224, any one of the lamp units 12 to 22 causes a short circuit / ground fault. It can be determined that an abnormality has occurred.

  In this case, the lamp unit 12 is compared to the case where the short-circuit / ground fault detection signal output from the short-circuit / ground fault detection circuits 54 to 64 is converted into an analog signal by a single D / A conversion circuit having 6-bit resolution. It can determine more correctly that abnormality accompanying short circuit and ground fault occurred in any of -22.

  In determining the abnormality of the lamp units 12 to 22, the D / A conversion circuit 72 and the D / A conversion circuit 74 having a 3-bit resolution are used for short circuits and ground faults, but accurate determination is not necessary. Sometimes, a single D / A conversion circuit having 6-bit resolution can be used.

  Further, although the D / A conversion circuit 70 having 6-bit resolution is used for an abnormality caused by the opening of the lamp units 12 to 22, two D / A conversion circuits having 3-bit resolution can be used.

  Further, the D / A conversion circuit 68 having a 5-bit resolution is used to control the lighting / extinguishing of the lamp units 12 to 22, but the resolution is 4 bits or less depending on the number of lamp units having different functions. A D / A conversion circuit or a D / A conversion circuit having a resolution of 6 bits or more can be used.

  According to the present embodiment, the microcomputer 76 is provided with only one A / D input terminal 164 for the five types of lamp units 12 to 22 having different functions. Since the lamp units 12 to 22 are controlled to be turned on and off based on the voltage input to the lamp unit 12, the number of input terminals for inputting an instruction signal for instructing the lamp units 12 to 22 to be turned on and off, The number of input instruction signals can be reduced, which can contribute to cost reduction.

  Further, according to the present embodiment, the microcomputer 76 can provide the A / D input only by providing the microcomputer 76 with one A / D input terminal 192 for the five types of lamp units 12 to 22 having different functions. An input for inputting an open detection signal of each of the lamp units 12 to 22 is made based on the voltage input to the terminal 192 because it is determined that an abnormality has occurred in any of the lamp units 12 to 22. The number of terminals and the number of open detection signals input to the microcomputer 76 can be reduced, which can contribute to cost reduction.

  Furthermore, according to the present embodiment, the microcomputer 76 is provided with only two A / D input terminals 208 and 224 for the five types of lamp units 12 to 22 having different functions. Since it is determined that an abnormality caused by a short circuit or ground fault has occurred in any of the lamp units 12 to 22 based on the voltage input to the D input terminals 208 and 224, a short circuit of each of the lamp units 12 to 22 is detected. The number of input terminals for inputting the ground fault detection signal and the number of inputs of the short circuit / ground fault detection signal to the microcomputer 76 can be reduced, which can contribute to cost reduction.

It is a block block diagram of the light-emitting device for vehicles which shows one Example of this invention. It is a circuit block diagram of a D / A conversion circuit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Light-emitting device for vehicles 12-22 Lamp unit 24 Lighting control device of a vehicle lamp 26 Switch circuit 28 Switching regulator 30-40 Current drive circuit 42-52 Opening detection circuit 54-64 Short circuit / ground fault detection circuit 66 Protection circuit 68- 74 D / A conversion circuit 76 Microcomputer

Claims (3)

In a lighting control device for a vehicle lamp that controls lighting of a plurality of lamp units having different functions,
An abnormality detecting means for detecting an abnormality of each lamp unit;
A digital-analog conversion means for converting a signal of the abnormality detection means into a normal / abnormal binary signal and converting a digital signal of a plurality of bits corresponding to the number of lamp functions into an analog signal;
An abnormality determining means for determining an abnormality of each lamp unit based on the analog converted signal;
A lighting control device for a vehicular lamp, comprising: In a lighting control device for a vehicle lamp that controls lighting of a plurality of lamp units having different functions,
A digital-analog conversion means for converting a multi-bit digital signal corresponding to the number of lamp functions into an analog signal, using a lamp unit on / off signal transmitted from the outside as a binary signal of lighting / extinguishing;
On / off control means for controlling on / off of each lamp unit based on the analog-converted signal,
A lighting control device for a vehicular lamp, comprising:   The lighting control apparatus for a vehicle lamp according to claim 1, wherein the abnormality detecting means includes a plurality of abnormality detecting means for detecting abnormality of each lamp unit according to its type, and the digital-analog converting means. A plurality of digital-analog conversion means for converting the digital signals output from the plurality of abnormality detection means into analog signals, respectively, and the abnormality determination means is based on the output signals of the plurality of digital-analog conversion means. A lighting control device for a vehicular lamp characterized by determining an abnormality of a lamp unit for each type.

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