一种升压型白光LED驱动控制芯片的设计

Design of a Boost WLED driver controller IC

针对高亮度白光LED的驱动要求,提出了一种适用于升压型LED驱动电路控制器的设计方案。针对LED的电气特性,芯片控制策略采用峰值电流模式控制并建立了小信号模型进行系统环路补偿设计;针对LED的背光应用要求,在控制器中集成了模拟与数字调光功能,具体介绍了数字调光模式的功能电路,其最大的调光比可以达到3000∶1。为了满足更高的效率要求,设计了无采样电阻的控制电路,减少了外围的器件并提高了系统的效率。芯片在1.5μm BCD工艺下设计并流片,最后进行了各种工作模式下的测试。测试结果显示,该芯片基本满足设计要求。

An integrated circuit （ IC ） controller for Boost converter was proposed. The controller could be applied to Step-up （Boost）topology, especially for high light LED driver circuit. According to the characteristics of LED, the peak current mode control strategy with slope compensation was adopted and establish the small signal model to design compensation network for whole system. To meeting the demands of LED back lighting, the digital and analog dimming circuits were integrated onto the chip, the PWM dimming function circuits were introduced and the maximum dimming ratio was up to 3 000 ： 1. In addition, a no sense resistor mode was introduced into the circuit, which results in reducing the peripheral components and enhancing the system efficiency. The controller was designed and fabricated in 1.5 μm BCD process and the different modes test results are consistent with design specifications well.