滞环电流控制的大功率LED恒流驱动芯片设计

设计了一款滞环电流控制的大功率LED恒流驱动芯片,其采用高边电流检测方案,通过内部电流检测电路对LED驱动电流进行滞环控制,从而获得恒定的平均电流。芯片采用9VBICMOS工艺流片,可输出350mA电流驱动1W的LED,也可输出750mA电流驱动3W的LED。在4.5～9V输入电压范围内,芯片输出驱动电流变化小于3.5%。在环境温度从25°C变化到100°C时,芯片输出驱动电流变化小于5%。由于滞环电流控制环路存在自稳定性,芯片无需补偿电路。

Design of a High Power LED Driver Using Hysteresis-current Control Technique

A chip using hysteresis-current control technique,which drives high power LED with a constant current,is designed and fabricated with 9V BICMOS process.Using high side current sense topology and inherent current sense circuit,it controls the driving current for LED in the mode of hysteresis-current to get a constant average current.The chip can provide a driving current of 350 mA or 750 mA for 1 W LED or 3 W LED respectively.Within the power supply range of 4.5～9 V,the output driving current can be controlled within the range of 3.5%.When the environment temperature changes from 25～100 °C,the driving current can be controlled within the range of 5%.Due to the self-stability of hysteresis-current control technique,the chip has no need of a compensating circuit.