Oscillator circuit
AssigneeRohm Co., Ltd.
InventorMasanobu Tsuji
Life of this patent
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Abstract
A frequency variable oscillator generates a clock having a frequency according to a control signal. A reference current source generates a reference current. A path selector distributes the reference current to a first path and a second path in a time-sharing manner in synchronization with the clock. An F/V conversion circuit includes a capacitor connected to the first path, and charges or discharges the capacitor with the reference current and generates a detection voltage. The reference voltage source includes a resistor connected to the second path, and outputs a reference voltage according to a voltage across the resistor. A feedback circuit adjusts a control signal so that the detection voltage approaches the reference voltage.
Claims10
An oscillator circuit comprising:
- a frequency variable oscillator structured to generate a clock having a frequency according to a voltage level of an analog control signal or a digital value of a digital control signal;
- a reference current source structured to generate a reference current;
- a path selector structured to distribute the reference current to a first path and a second path in a time-sharing manner in synchronization with the clock;
- an F/V conversion circuit including a capacitor connected to the first path and structured to charge or discharge the capacitor with the reference current and generate a detection voltage, wherein the detection voltage has a voltage level according to the frequency of the clock;
- a reference voltage source including a resistor connected to the second path and structured to output a reference voltage according to a voltage across the resistor;
- and
- a feedback circuit structured to adjust the voltage of the analog control signal or the digital value of the digital control signal so that the detection voltage approaches the reference voltage with a feedback manner.
Dependencies are inferred from the claim text.