浅谈On Semi NCV7692轿车LED灯电流操控的解刨

On Semi公司的NCV7692轿车LED灯电流操控器,选用外接NPN双极器材和反应电阻来调整驱动LED的电流.单个驱动器使用户能灵敏添加单路到多路体系中.专用的调光特性经过PWM输入引脚来完成.当检测到开路或短路时单路驱动器就开关断.LED亮度选用串联在双极晶体管的外接电阻进行编程.单个NCV7692可驱动多个LED串.NCV7692可选用PWM操控,外接可编电流电阻,可选择负温度体系电流操控,开路LED串和短路LED串确诊,多个LED串操控,满意AEC−Q100 标准和PPAP功用.首要用在轿车后组合灯(RCL),日间灯(DRL),雾灯,中心高位刹车灯(CHMSL)阵列,转向灯和其它外部调制使用,通用轿车线性电流LED驱动器.本文介绍了NCV7692首要特性,框图和多种使用框图,以及评价板EVBUM2664首要特性,电路图和评价板EVBUM2664使用电路与PCB规划图.

The NCV7692 is a device which uses an external NPN bipolar device combined with feedback resistor(s) to regulate a current for use in driving LEDs. The target application for this device is automoTIve rear combinaTIon lamps. A single driver gives the user flexibility to add single channels to mulTIchannel systems. A dedicated dimming feature is included via the PWM input pin. The individual driver is turned off when an open load or short circuit is detected.

LED brightness levels are easily programmed using an external resistor in series with the bipolar transistor. The use of the resistor gives the user the flexibility to use the device over a wide range of currents. MulTIple strings of LEDs can be operated with a single NCV7692 device. Set back power limit reduces the drive current during overvoltage conditions.

The device is available in a SOIC−8 package.

NCV7692首要特性:

• Constant Current Output for LED String Drive
• External Bipolar Device for Wide Current Range Flexibility
♦ With BCP56 Transistor, Can Drive Multiple Strings Concurrently (ref. Datasheet Info)
• External Programming Current Resistor
• Pulse Width Modulation (PWM) Control
• Negative Temperature Coefficient Current Control Option
• Open LED String Diagnostic
• Short−Circuit LED String Diagnostic
• Multiple LED String Control
• Overvoltage Set Back Power Limitation
• SOIC−8 Package
• AEC−Q100 Qualified and PPAP Capable
• These are Pb−Free Devices

NCV7692使用:

• Rear Combination Lamps (RCL)
• Daytime Running Lights (DRL)
• Fog Lights
• Center High Mounted Stop Lamps (CHMSL) Arrays
• Turn Signal and Other Externally Modulated Applications
• General Automotive Linear Current LED Driver

图1.NCV7692框图

图2.NCV7692使用框图

图3.NCV7692微处理器操控使用框图

图4.NCV7692输出驱动配置图

图5.NCV7692负温度补偿作业电路图

 
图6.NCV7692短路检测电路图
 

图7.NCV7692 4或更多路的短路检测图

图8.NCV7692 短路维护图

图8.NCV7692 SmartFET操控电路图

图9.NCV7692刹车灯/尾灯使用电路图

图10.NCV7692大电流时刹车灯/尾灯使用电路图

图11.NCV7692没有微处理器的使用框图

评价板EVBUM2664

NCV7692 High-currentDaylight Running LightEvaluation Board

The evaluation board demonstrates high−current daylight running light (DRL) solution. The board regulates constant current of 0.54 A through two on−board white high power LEDs in the wide range of the supply voltage. The current is reduced for the board temperature above 85°C. The cooling is provided through passive heat sink mounted on the bottom side of the board. In case of LEDs short or opening, the current source is disabled and the fault may be detected by the ECU diagnostics.

评价板EVBUM2664首要特性:

• Wide range of supply voltage: 7 to 40 V (thermally limited)
• Two high−brightness on−board white LEDs
• Nominal LED current of 0.54 A
• Over−temperature current fold−back protection
• LED short−circuit and open−load emulation jumpers
• Positions for optional EMC capacitors
• One−side components assembly
• Passive cooling (heat sink)

图12.评价板EVBUM2664外形图

图13.评价板EVBUM2664大电流白日运转电路图

图14.NCV7692大电流DRL板外形图

图15.NCV7692一线驱动器车身电子操控单元(ECU)框图

图16.NCV7692 DRL EVB PCB规划图:左:顶层装配图;右:顶层归纳图

图17.NCV7692 DRL EVB PCB规划图:顶层边视图

图18.NCV7692 DRL EVB PCB规划图:底层边视图

图19.NCV7692DRLV1GEVB评价板电路图