Crystal oscillation circuit and electronic timepiece

Patent metadata

Field	Value
Publication number	US-9634608-B2
Application number	US-201514836625-A
Country	US
Kind code	B2
Filing date	Aug 26, 2015
Priority date	Sep 3, 2014
Publication date	Apr 25, 2017
Grant date	Apr 25, 2017

Abstract

To provide a crystal oscillation circuit low in current consumption and stably short in oscillation start time. A crystal oscillation circuit is equipped with a crystal vibrator, a feedback resistor, a bias circuit, a constant voltage circuit, and an oscillation inverter configured by a constant current inverter. The oscillation inverter is configured so as to be controlled by currents based on input signals from the bias circuit and the crystal vibrator and driven by an output voltage of the constant voltage circuit.

First claim

What is claimed is:

1. A crystal oscillation circuit, comprising:
a crystal vibrator;
a feedback resistor;
a bias circuit;
a constant voltage circuit; and
an oscillation inverter configured by a constant current inverter comprising a current source transistor and a transistor configuring an inverter that are connected in series, wherein a gate of the current source transistor is connected to an output terminal of the bias circuit through a resistor and connected to an input terminal of the crystal vibrator through a capacitor
said oscillation inverter being controlled by currents based on input signals from the bias circuit and the crystal vibrator and driven by an output voltage of the constant voltage circuit.

2. The crystal oscillation circuit according to claim 1 , wherein at least either of the output voltage of the constant voltage circuit and the currents based on the input signals is increased at the start of oscillation.

3. An electronic timepiece equipped with the crystal oscillation circuit according to claim 1 .

Assignees

• Seiko Instr Inc
• Sii Semiconductor Corp

Inventors

• Watanabe Kotaro
• Mitani Makoto

Classifications

• H03L5/00

  Automatic control of voltage, current, or power · CPC title

• H03B5/364 Primary

  the amplifier comprising field effect transistors (H03B5/366 takes precedence) · CPC title

• G04G3/00

  Producing timing pulses (driving circuits for stepping motors G04C3/14; producing preselected time intervals for use as timing standards G04F5/00; pulse technique in general H03K; control, synchronisation, or stabilisation of generators in general H03L) · CPC title

• H03B2200/0062

  Bias and operating point · CPC title

• H03B5/32

  being a piezoelectric resonator (selection of piezoelectric material H10N30/00) · CPC title