Patent ID: 9030265
Filing Date: 2015-05-12
Classification: G04F,H03B

Abstract:
1. A crystal oscillator that generates an output oscillating signal by a crystal, the crystal oscillator comprising: a first pad and a second pad, coupled to two nodes of the crystal; an amplifier, coupled to the first pad, for amplifying a crystal oscillating signal received from the first pad and generating an amplifying signal, wherein the amplifier comprises: a first transistor, having a first gate for receiving the crystal oscillating signal, having a first source coupled to a first operating voltage; a second transistor, having a second drain coupled to a first drain of the first transistor, having a second source coupled to a second operating voltage; a third transistor, having a third gate coupled to a second gate of the second transistor, having a third source coupled to the second operating voltage; and a fourth transistor, having a fourth drain coupled to a third drain of the third transistor, having a fourth source coupled to the first operating voltage, wherein the second and the third transistors form a current mirror circuit, wherein the first and the fourth transistors are implemented by NMOS transistors and the second and the third transistors are implemented by PMOS transistors; and an inverter, coupled to the amplifier, for inverting the amplifying signal and generating the output oscillating signal, wherein the amplifier has a first power consumption, the inverter has a second power consumption, and the first power consumption is smaller than the second power consumption.