# US 2019/0356320 A1 · Circuit device, oscillator, electronic apparatus and vehicle

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- Number: US 2019/0356320 A1
- Document ID: US20190356320A1
- Status: Published application
- Kind: A1
- Application number: 16/412,907
- Filed: 2019-05-15
- Published: 2019-11-21
- Earliest claimed: 2018-05-16
- Assignees: Seiko Epson Corporation
- Applicants: Seiko Epson Corporation
- Inventors: Kentaro SEO
- Web page: https://patentgrep.com/patent/US20190356320A1

## CPC

- H03L 7/0992: {comprising a counter or a frequency divider}
- H03L 7/18: using a frequency divider or counter in the loop (H03L7/20, H03L7/22 take precedence)
- H03L 1/028: {of generators comprising piezoelectric resonators (H03L1/021, H03L1/022 take precedence; oscillation generators with a piezoelectric resonator H03B5/32)}
- H03L 7/093: using special filtering or amplification characteristics in the loop (H03L7/087 - H03L7/091 take precedence)
- H03L 7/14: for assuring constant frequency when supply or correction voltages fail
- H03J 2200/11: Cellular receiver, e.g. GSM, combined with a GPS receiver
- H03L 2207/50: All digital phase-locked loop
- H03L: AUTOMATIC CONTROL, STARTING, SYNCHRONISATION OR STABILISATION OF GENERATORS OF ELECTRONIC OSCILLATIONS OR PULSES (generation of oscillations H03B)
- H03J: TUNING RESONANT CIRCUITS; SELECTING RESONANT CIRCUITS

## Abstract

A circuit device includes an oscillation signal generation circuit for generating an oscillation signal with an oscillation frequency set by frequency control data, and a processing circuit. The processing circuit includes a counter for performing a count process based on the oscillation signal, and a latch circuit for holding a count value of the counter based on a reference signal. The processing circuit performs a loop filter process on a phase comparison result based on output data of the latch circuit to output the frequency control data, holds information based on the phase comparison result when the holdover is detected, and outputs the frequency control data based on the information held, in a holdover period.

## Claims

### Claim 1

A circuit device comprising:
an oscillation signal generation circuit configured to, using frequency control data and a resonator, generate an oscillation signal with an oscillation frequency set by the frequency control data; and
a processing circuit that receives the oscillation signal and a reference signal, and that outputs the frequency control data to the oscillation signal generation circuit,
wherein
the processing circuit includes
a counter configured to perform, based on the oscillation signal, a count process at a cycle set by a frequency control word, and
a latch circuit configured to hold a count value of the counter based on the reference signal, and
the processing circuit
performs a loop filter process on a phase comparison result based on output data of the latch circuit to output the frequency control data,
holds information based on the phase comparison result when holdover due to disappearance or a defect of the reference signal is detected, and
outputs the frequency control data based on the information held, in a holdover period.