CN-115529691-B - Lamp for vehicle, driving circuit and driving integrated light source

CN115529691BCN 115529691 BCN115529691 BCN 115529691BCN-115529691-B

Abstract

A lighting circuit (200) lights up a plurality of semiconductor light sources (102). The plurality of current sources (2101) - (210N) __ are respectively connected in series with the corresponding semiconductor light sources (102). A switching converter (220) supplies a drive Voltage (VOUT) to both ends of each of a plurality of series connection circuits formed by a plurality of semiconductor light sources (102) and a plurality of current sources (210). The converter controller (230) controls the switching transistor (M1) of the switching converter (220) in accordance with a relationship between a Voltage (VLED) across any one of the plurality of current sources (210) and a reference voltage having a positive correlation with the temperature (Tj).

Inventors

ICHIKAWA TOMOYUKI
Ju Chixian
Song Hualiangyou

Assignees

株式会社小糸制作所

Dates

Publication Date: 20260512
Application Date: 20190403
Priority Date: 20180410

Claims (9)

1. A driving circuit for supplying a driving current to a plurality of semiconductor light sources used as a vehicle lamp, comprising: a plurality of current sources for being connected in series with a corresponding one of the plurality of semiconductor light sources, and capable of conducting on/off control based on a binary control input, An interface circuit which is communicable with a processor of the lamp ECU, receives control signals indicating on and off of the respective plurality of semiconductor light sources from the processor, generates a plurality of binary individual control signals based on the control signals, and outputs the plurality of binary individual control signals through a plurality of wirings, and And a protection circuit having a plurality of input terminals for receiving the plurality of binary individual control signals through the plurality of wirings and a plurality of output terminals connected to the plurality of current sources, for monitoring communication between the processor and the interface circuit, and outputting the plurality of individual control signals directly as the plurality of control inputs from the plurality of output terminals when the communication is normal, and outputting a combination of predetermined values as the plurality of control inputs from the plurality of output terminals when an abnormality is detected in the communication.
2. The driving circuit according to claim 1, wherein, The combination of the predetermined values is set to form a light distribution state corresponding to the light distribution of the low beam.
3. The driving circuit according to claim 1, wherein, The protection circuit includes: An abnormality detection circuit for asserting an abnormality detection signal when the abnormality is detected, an And a data replacement circuit configured to directly output the plurality of individual control signals from the plurality of output terminals when the abnormality detection signal is inactive, and to output a combination of predetermined values from the plurality of output terminals when the abnormality detection signal is active.
4. The driving circuit according to claim 3, wherein, The data replacement circuit includes: an inverter for inverting the abnormality detection signal to generate an inverted abnormality detection signal, A plurality of 1 st logic gates corresponding to a plurality of current sources among the plurality of current sources, the plurality of current sources being turned on when the abnormality is detected, and A plurality of 2 nd logic gates corresponding to a plurality of current sources out of the plurality of current sources, the plurality of current sources being turned off when the abnormality is detected; Each 1 st logic gate receives a corresponding individual control signal from one of the abnormality detection signal and the inverted abnormality detection signal and supplies its output to a corresponding current source; Each of the 2 nd logic gates receives a corresponding individual control signal from the other of the abnormality detection signal and the inverted abnormality detection signal, and supplies its output to a corresponding current source.
5. The driving circuit according to any one of claim 1 to 4, wherein, The protection circuit determines that the signal is abnormal when the level transition does not occur for a predetermined period of the control signal.
6. A drive-integrated light source, comprising: A plurality of semiconductor light sources integrated in the 1 st semiconductor chip, and The driving circuit according to any one of claims 1 to 5, which is bonded to a2 nd semiconductor chip.
7. A lamp for a vehicle, characterized in that, A drive circuit comprising any one of claims 1 to 5.
8. A lamp for a vehicle, characterized in that, is configured to include: The upper-level controller is used for controlling the upper-level controller, An interface circuit for receiving a control signal from the upper controller, The light distribution variable device comprises a light distribution control unit, A local controller for controlling the variable light distribution device based on the control signal received by the interface circuit, and outputting a plurality of control signals for instructing on or off of a plurality of current sources in the variable light distribution device through a plurality of wirings, respectively, and A 1 st abnormality detection unit that monitors communication between the upper controller and the interface circuit and detects an abnormality; When the abnormality is detected, a predetermined light distribution pattern is formed by replacing the plurality of control signals with a combination of predetermined values.
9. The vehicular lamp according to claim 8, wherein, The system also comprises a2 nd abnormality detection part, wherein the 2 nd abnormality detection part monitors the output of the local controller and detects abnormality.

Description

Lamp for vehicle, driving circuit and driving integrated light source Technical Field The present invention relates to a lighting circuit. Background A vehicle lamp is generally switchable between a low beam and a high beam. The low beam illuminates the vicinity of the host vehicle with a predetermined illuminance, and sets a light distribution regulation so as not to cause glare to the oncoming vehicle or the preceding vehicle, and is mainly used when traveling in an urban area. On the other hand, high beam is used to illuminate a wide area ahead and a far distance with relatively high illuminance, and is mainly used when traveling at high speed on a road where there are few oncoming vehicles or preceding vehicles. Therefore, the high beam has better visibility for the driver than the low beam, but there is a problem in that glare is caused to the driver or the pedestrian of the vehicle existing in front of the vehicle. In recent years, an ADB (ADAPTIVE DRIVING Beam: adaptive high Beam) has been proposed that dynamically and adaptively controls a light distribution pattern of the high Beam based on a state around a vehicle. The ADB technology detects whether a vehicle is in front of a preceding vehicle, a oncoming vehicle, or a pedestrian, and reduces or extinguishes light in an area corresponding to the vehicle or the pedestrian, thereby reducing glare to the vehicle or the pedestrian. Fig. 1 is a block diagram of an ADB-enabled luminaire system 1001. The lighting system 1001 includes a battery 1002, a switch 1004, a switching converter 1006, a plurality of light emitting units 1008_1-1008_N and a plurality of current sources 1010_1-1010_N, a converter controller 1012, and a light distribution controller 1014. The plurality of light emitting units 1008_1 to 1008_n are semiconductor light sources such as LEDs (light emitting diodes) or LDs (laser diodes), and are associated with a plurality of different areas on a virtual vertical screen in front of the vehicle. The plurality of current sources 1010_1 to 1010_n are arranged in series with the corresponding plurality of light emitting units 1008_1 to 1008_n. The driving current ILEDi generated by the current source 1010_i flows through the ith (1≤i≤n) light emitting cell 1008i. The plurality of current sources 1010_1 to 1010_n are configured to be independently turned on and off (or the amount of current). The light distribution controller 1014 controls the on/off (or the amount of current) of the plurality of current sources 1010_1 to 1010_n to obtain a desired light distribution pattern. The constant voltage output switching converter 1006 generates a driving voltage VOUT that is sufficient to cause the plurality of light emitting units 1008_1 to 1008_n to emit light with a desired luminance. Next, attention is paid to the i-th channel. The voltage drop (forward voltage) of the light emitting unit 1008—i when a certain driving current ILEDi flows is denoted as VFi. In addition, the current source 1010—i is required to have a voltage across it (hereinafter referred to as a saturation voltage VSATi) larger than a certain voltage in order to generate the drive current ILEDi. Thus, with respect to the ith channel, the following inequality should be established. VOUT>VFi+VSATi...(1) This relationship needs to be established in all channels. [ Prior Art literature ] [ Patent literature ] Patent document 1 Japanese patent application laid-open No. 2009-012669 Patent document 2 Japanese patent application laid-open No. 2015-138763 Disclosure of Invention [ Problem to be solved by the invention ] Problem 1. In order to establish inequality (1) in any situation, the target value VOUT (REF) of the output voltage VOUT is set high in consideration of the margin as shown in expression (2) with the output voltage VOUT as a control target for feedback, and feedback control may be applied so that the output voltage VOUT of the switching converter 1006 coincides with the target value VOUT (REF). VOUT(REF)=VF(MERGIN)+VSAT(MERGIN)...(2) VF (TYP) is the maximum value (or typical value) of VF with a margin added. VSAT (MERGIN) is a saturation voltage VSAT to which a margin is added. When this control is performed, a difference between the saturation voltage VSAT (MERGIN) and the actual saturation voltage VSAT is applied to the current source 1010, and thus unnecessary power loss is generated. In addition, in the case where the actual forward voltage VF is lower than VF (MERGIN), their difference may be included in the voltage drop of the current source 1010, thereby generating unnecessary power loss. In the vehicle lamp, it is necessary to cause a very large current to flow to the light emitting unit, and it is difficult to take a countermeasure against heat dissipation as compared with other devices, so that it is necessary to reduce the amount of heat generation in the current source as much as possible. Problem 2. The spatial resolution of the light distribution pattern for