Patent ID: 7127628

Claim:
A method for automatically regulating an oscillator applicable to a low-speed USB interface connecting system, comprising the steps of: (a) providing a voltage-controlled oscillator in a USB interface so that a controllable oscillating signal is generated by said voltage-controlled oscillator to a USB electronic device; (b) feeding back said controllable oscillating signal to a frequency comparing unit which is used to compare said controllable oscillating signal with a Keep Alive Strobe signal in said USB interface in order to find a difference between frequencies of said controllable oscillating signal and said Keep Alive Strobe signal; (c) inputting an output signal of the frequency comparing unit to a frequency regulating unit where the frequency of said controllable oscillating signal is changed according to a signal regulating voltage fed back from said frequency comparing unit; and (d) repeating steps (b) and (c) to synchronize said controllable oscillating signal with said Keep Alive Strobe signal in said USB interface.