US 10,763,786 B1 · Differential crystal oscillator

Abstract

A differential crystal oscillator circuit is disclosed. The differential crystal oscillator circuit includes an output port. The output port includes a first terminal and a second terminal. A resonance port is included to couple a resonance element to the differential crystal oscillator circuit. The differential crystal oscillator includes a current source. A differential amplifier is included to excite the resonance element. The differential amplifier is coupled to the current source and the resonance port. The differential amplifier includes a plurality of transistors. The differential crystal oscillator circuit further includes a low pass filter that in combination with a transistor in the differential amplifier exhibits characteristics of a high pass filter. The differential amplifier is configured to use the current source as an active load.

Claims15

Dependent claims

A differential crystal oscillator circuit, comprising:

an output port including a first terminal and a second terminal;
a resonance port to couple a resonance element;
a current source;
a differential amplifier coupled to the current source and the resonance port, wherein the differential amplifier includes a plurality of transistors, a resistor and a capacitor, wherein the resistor and the capacitor form a low pass filter that in combination with a transistor in the differential amplifier exhibits characteristics of a high pass filter;
and
wherein the differential amplifier is configured to use the current source as an active load, wherein the active load including a control port to receive an external biasing voltage to control amplitude of an output signal at the output port.

3 more elements

Dependencies are inferred from the claim text.

Differential crystal oscillator

Life of this patent

Differential crystal oscillator

Life of this patent

Abstract

Claims15