Circuit apparatus and oscillator
AssigneeSeiko Epson Corporation
InventorTomohiro Uno
Life of this patent
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Abstract
A circuit apparatus includes: a first oscillation circuit configured to generate a first clock signal; a PLL circuit including a second oscillation circuit configured to generate a second clock signal and a frequency control voltage generation circuit configured to generate a frequency control voltage for controlling a frequency of the second clock signal, the PLL circuit being configured to synchronize a phase of the second clock signal with a phase of the first clock signal; and a failure detection circuit configured to monitor the frequency control voltage and detect whether there is a possibility that the frequency control voltage deviates from a predetermined voltage range in which the second oscillation circuit is capable of operating normally.
Claims7
A circuit apparatus comprising:
- a first oscillation circuit configured to generate a first clock signal;
- a PLL circuit including a second oscillation circuit configured to generate a second clock signal and a frequency control voltage generation circuit configured to generate a frequency control voltage for controlling a frequency of the second clock signal, the PLL circuit being configured to synchronize a phase of the second clock signal with a phase of the first clock signal;
- a failure detection circuit configured to monitor the frequency control voltage and detect whether there is a possibility that the frequency control voltage deviates from a predetermined voltage range in which the second oscillation circuit is capable of operating normally;
- and
- an A/D conversion circuit configured to perform A/D conversion on the frequency control voltage and a temperature detection voltage, wherein
- the failure detection circuit calculates, based on an A/D conversion result of the frequency control voltage and an A/D conversion result of the temperature detection voltage, frequency control voltage data obtained by removing a voltage component that changes according to a temperature from the frequency control voltage, and predicts, based on the frequency control voltage data, a timing when the frequency control voltage deviates from the predetermined voltage range.
Dependencies are inferred from the claim text.