Analog amplitude control circuit to optimize drive level of crystal oscillator
AssigneeSynopsys, Inc.
InventorsJayanthi Sri Ram Kumar, Rahul Gupta
Life of this patent
Estimating the term…
Abstract
A circuit includes, in part, a transconductance amplifier, a common source amplifier, a resistor, and NMOS transistor. The common source amplifier is coupled to an output of the transconductance amplifier and generates a signal coupled to an output terminal of a crystal oscillator circuit. The resistor is coupled between the transconductance amplifier and the ground terminal. The NMOS transistor has a drain terminal coupled to a first terminal of the first resistor, a source terminal coupled to a second terminal of the first resistor, and a gate terminal coupled to an input terminal of the common source amplifier and to an input terminal of the crystal oscillator circuit.
Claims20
A circuit comprising:
- a transconductance amplifier;
- a common source amplifier coupled to an output of the transconductance amplifier and generating a signal coupled to an output terminal of a crystal oscillator circuit;
- a first resistor coupled between the transconductance amplifier and a ground terminal;
- and
- a first NMOS transistor having a drain terminal coupled to a first terminal of the first resistor, a source terminal coupled to a second terminal of the first resistor, and a gate terminal coupled to an input terminal of the common source amplifier and to an input terminal of the crystal oscillator circuit.
A method comprising:
- forming a transconductance amplifier;
- coupling an output of the transconductance amplifier to a common source amplifier, the common source amplifier generating a signal coupled to an output terminal of a crystal oscillator circuit;
- coupling a first resistor between the transconductance amplifier and a ground terminal;
- and
- forming a first NMOS transistor having a drain terminal coupled to a first terminal of the first resistor, a source terminal coupled to a second terminal of the first resistor, and a gate terminal coupled to an input terminal of the common source amplifier and to an input terminal of the crystal oscillator circuit.
A non-transitory computer readable medium comprising stored instructions, which when executed by a processor, cause the processor to generate a circuit design comprising:
- a transconductance amplifier;
- a common source amplifier coupled to an output of the transconductance amplifier and generating a signal coupled to an output terminal of a crystal oscillator circuit;
- a first resistor coupled between the transconductance amplifier and a ground terminal;
- and
- a first NMOS transistor having a drain terminal coupled to a first terminal of the first resistor, a source terminal coupled to a second terminal of the first resistor, and a gate terminal coupled to an input terminal of the common source amplifier and to an input terminal of the crystal oscillator circuit.
Dependencies are inferred from the claim text.