A Novel PWM Controller IC for LED Driver with Frequency Spread

Abstract-An effective Pulse Width Modulation controller IC with frequency spread for LED driver is presented in this paper. Maintaining a steady current in different conditions is critical for LED systems, while in practical applications, the LED current would have a severe problem of electromagnetic interference (EMI). Therefore, a novel frequency spread module is proposed to improve the EMI performance. The driver IC adopts peak current mode as its controlling strategy. The working frequency is spread with a rate of +2~4% up and down its central frequency. The input voltage can vary from 8.5 V to 40 V and the output current would change from several mA to 1 A, according to different applications. The controller is designed and simulated by using CSMC´s l¿m 40 V standard CMOS process.