Oscillator
AssigneeSeiko Epson Corporation
InventorMakoto OKEYA
Life of this patent
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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.
Claims6
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 configured to negatively feed the reference current back to between a gate and source of the transistor;
- the resistance of the feedback element having a gradient to temperature change whereby the gradient of the difference between the constant voltage and the stop-oscillating voltage to temperature change approaches 0.
Dependencies are inferred from the claim text.