Clock-generating circuit

Abstract

A clock-generating circuit is provided, which includes a voltage-reference circuit, a tracking-voltage-generating circuit, a voltage regulator, an oscillation generator, and a level shifter. The voltage-reference circuit and the tracking-voltage-generating circuit respectively convert the external voltage into a reference voltage and a temporary reference voltage. The voltage regulator receives the reference voltage and the temporary reference voltage, and it converts the reference voltage or the temporary reference voltage into an oscillation power-supply voltage. The oscillation generator generates a first clock signal according to the oscillation power-supply voltage. The level shifter converts a voltage amplitude of the first clock signal to generate a second clock signal that is output by the clock-generating circuit. The voltage regulator includes a switch circuit for controlling whether to pull up the oscillation power-supply voltage, which is at an output terminal of the voltage regulator, to the external voltage according to an enable signal.

Dependencies are inferred from the claim text.