论文部分内容阅读
为了解决传统LED驱动器引入的电磁干扰(EMI)问题,提出了一种具有扩频功能的片内振荡器。该电路采用频率扩展技术对时钟进行频率调制,可有效抑制电磁干扰,并具有固定频率模式(FFM)和扩频模式(FEM)两种工作模式,且固定频率时温度漂移小。采用0.18μm BCD进行了工艺仿真,结果表明:扩频模式下,振荡器的中心频率为558kHz,扩频范围为6.09%,频率抖动周期为57.8μs,EMI能量降幅高达12dB,显著降低了电磁干扰,适用于对电磁兼容(EMC)性能要求很高的特定LED驱动器中。
In order to solve the electromagnetic interference (EMI) problem introduced by the traditional LED driver, an on-chip oscillator with spread spectrum function is proposed. The circuit uses the frequency expansion of the clock frequency modulation technology, which can effectively suppress the electromagnetic interference and has a fixed frequency mode (FFM) and spread spectrum mode (FEM) two modes of operation, and a fixed frequency temperature drift is small. The simulation results show that, in the spread spectrum mode, the center frequency of the oscillator is 558kHz, the spreading range is 6.09%, the frequency dithering period is 57.8μs, and the EMI energy drop is as high as 12dB, which reduces the electromagnetic interference , For specific LED drivers that require high EMC performance.