Oscillator having feedback path which is capable of supplying reduced voltage potential to oscillation circuit
AssigneeNEC Electronics Corporation
InventorHiroyuki Aoki
Life of this patent
Estimating the term…
Abstract
An oscillator creates a reference voltage based on a pulse signal corresponding to an oscillation output of a crystal oscillation circuit and controls a supply voltage to the crystal oscillation circuit according to the reference voltage. A control signal creating circuit creates a control signal based on the pulse signal and reference voltage generating circuits that control the reference voltage based on the control signal. The control signal creating circuit creates a low-level control signal when the pulse signal is in a low level, creates a high-level control signal when the pulse signal is in a high level, and prevents transition of the control signal from the high level to the low level.
Claims14
An oscillator that creates a reference voltage based on a pulse signal corresponding to an oscillation output of an oscillation circuit, and that controls a maximum voltage level supplied to the oscillation circuit according to the reference voltage, the oscillator comprising:
- a control signal creating circuit that creates a first reference voltage control signal and a second reference voltage control signal based on the pulse signal;
- and
- a reference voltage generating circuit that creates a first reference voltage when receiving the first reference voltage control signal, and that creates a second reference voltage lower than the first reference voltage when receiving the second reference voltage control signal,
- wherein the control signal creating circuit creates the first reference voltage control signal when the pulse signal is in a first logic level, creates the second reference voltage control signal when the pulse signal is in a second logic level different from the first logic level, and prevents transition from the second reference voltage control signal to the first reference voltage control signal when the pulse signal changes from the second logic level to the first logic level.
An oscillator, comprising:
- an oscillation circuit;
- a level detection circuit which receives an output from the oscillation circuit and outputs a detection signal;
- a first inverter which receives the detection signal;
- a capacitor coupled to an output of the first inverter;
- a second inverter which includes an input coupled to the output of the first inverter and outputs a control signal;
- and
- a reference voltage generator which produces a reference voltage for driving the oscillation circuit, based on the control signal.
An oscillator, comprising:
- an oscillation circuit operated by a voltage corresponding to one of a first reference voltage and a second reference voltage lower than the first reference voltage;
- a level detection circuit which receives an output from the oscillation circuit and outputs a first detection signal only having a first voltage potential during a time interval at a first period, and outputs a second detection signal having the first voltage potential and a second voltage potential repeatedly during the time interval at a second period;
- a control signal generator which generates a control signal having only a first voltage potential level when receiving the first detection signal, and generates the control signal having only a second voltage potential level when receiving the second detection signal;
- and
- a reference voltage generator which produces the first reference voltage based on the control signal having only the first voltage potential level, and produces the second reference voltage based on the control signal having only the second voltage potential level.
Dependencies are inferred from the claim text.