Patent ID: 8570080

Claim:
A signal generation device to generate an output signal with constant frequency, comprising: a frequency-control circuit, charging/discharging a voltage-control node according to a comparison result signal; and a voltage-controlled delay line, generating a control signal according to the comparison result signal and a control voltage of the voltage-control node to control the output signal, wherein a frequency of the control signal is modulated by the voltage-controlled delay line according to the control voltage of the voltage-control node, and wherein the comparison result signal is generated according to a difference between a reference voltage and a voltage level of the output signal; and wherein the frequency-control circuit comprises: a pulse generator, generating a reference pulse signal according to a transition of a reference signal and a comparison pulse signal according to a transition of the comparison result signal, to re-shape the reference signal and the comparison result signal into narrow pulses suitable for clocking and resetting flip-flops.