Circuit and method for producing USB host working clock

摘要

A circuit for producing USB host working clock comprises: an internal oscillator, a controllable frequency divider, a frequency multiplier, a USB host interface, and a frequency division controller. According to the frequency multiplier providing clock, the USB host interface configures with USB peripherals for responding. The frequency division controller is connected to the USB host interface and the controllable frequency divider. The USB host interface transmits a response result that the USB host interface configures with USB peripherals for responding to the frequency division controller. According to the USB host interface feeding back the response result, the frequency division controller regulates a frequency dividing ratio of the controllable frequency divider in set scope of the frequency dividing ratio. After regulating the frequency dividing ratio of the controllable frequency divider, the frequency division controller controls the controllable frequency divider that is processed with frequency division in fixed frequency dividing ratio.