Oscillator

Patent metadata

Field	Value
Publication number	US-10747248-B2
Application number	US-201916363139-A
Country	US
Kind code	B2
Filing date	Mar 25, 2019
Priority date	Mar 26, 2018
Publication date	Aug 18, 2020
Grant date	Aug 18, 2020

Abstract

Across the entire operating temperature range, and without requiring a new transistor element, the constant voltage output by a constant voltage circuit can be controlled to a voltage greater than or equal to the stop-oscillating voltage and as low as possible. A resistance 11b that negatively feeds back a reference current Iref is connected between the gate and source of a depletion mode n-channel transistor 11a configured to produce the reference current Iref on which the constant voltage VREG is based. The resistance of resistance 11b has a gradient to temperature change of the same sign as the gradient of the difference between the constant voltage and the stop-oscillating voltage to temperature change when the gradient of the resistance value of the resistance to temperature change is 0.

First claim

What is claimed is:

1. An oscillator comprising:
a constant voltage circuit including a constant current source that generates a reference current, and a constant voltage generator that generates a constant voltage according to the reference current; and
an oscillation circuit configured to oscillate when the constant voltage is applied, and stop oscillating when the constant voltage goes to or below a stop-oscillating voltage in a specific temperature range;
the constant current source including:
a depletion mode transistor configured to produce the reference current; and
a feedback element connected between a gate and source of the transistor;

a resistance of the feedback element having a gradient to temperature change whereby the gradient of a difference between the constant voltage and the stop-oscillating voltage to temperature change is 0.

2. The oscillator described in claim 1 , wherein:
the constant voltage increases as the reference current increases; and
when the gradient of the resistance of the feedback element to temperature change is 0, a sign of the gradient of the resistance of the feedback element to temperature change is the same as a sign of the gradient of the difference between the constant voltage and the stop-oscillating voltage to temperature change.

3. The oscillator described in claim 1 , wherein:
the constant voltage generator produces a constant voltage that decreases as the reference current increases; and
when the gradient of the resistance of the feedback element to temperature change is 0, a sign of the gradient of the resistance of the feedback element to temperature change is the different from a sign of the gradient of the difference between the constant voltage and the stop-oscillating voltage to temperature change.

4. The oscillator described in claim 1 , wherein the feedback element is a resistance.

5. A timepiece movement comprising an oscillator as described in claim 1 .

6. A timepiece comprising a timepiece movement as described in claim 5 .

Assignees

• Seiko Epson Corp

Inventors

• Okeya Makoto

Classifications

• H03B5/1231 Primary

  the amplifier comprising one or more bipolar transistors · CPC title

• H10D84/0163

  the components including enhancement-mode IGFETs and depletion-mode IGFETs · CPC title

• H10D84/83

  of only insulated-gate FETs [IGFET] · CPC title

• H10D84/038

  using silicon technology, e.g. SiGe · CPC title

• G05F1/463

  Sources providing an output which depends on temperature · CPC title