| 摘要 |
A pulse frequency modulation oscillating circuit includes a reference voltage generator for generating a first reference voltage and a second reference voltage, a first comparison circuit for comparing a state signal with the first reference voltage, a second comparison circuit for comparing the state signal with the second reference voltage, an output circuit for outputting a pulse frequency modulation signal according to an under-voltage signal, and signals outputted from the first comparison circuit and from the second comparison circuit, a mode generation circuit for generating the state signal, and a mode decision circuit for outputting inverse signals of the signals outputted from the first comparison circuit or signals outputted from the output circuit to the mode generation circuit according to the pulse frequency modulation signal, the under-voltage signal, and the signals outputted from the first comparison circuit and from the second comparison circuit.
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