Isolation integrated circuit, carrier frequency control circuit and modulation signal generation method

A carrier frequency control circuit, electrically coupled to a carrier frequency generation circuit, wherein the carrier frequency control circuit is configured to receive an input signal, and comprises:

• an edge detection circuit, configured to output at least one rising signal during at least one enabling period of the input signal and to output at least one falling signal during at least one disabling period of the input signal;
• a timing pulse generation circuit, electrically coupled to the edge detection circuit, and configured to output a frequency filtering signal and to generate at least one timing pulse by adjusting a voltage level of the frequency filtering signal according to the at least one falling signal, wherein when an output period of one of the at least one timing pulse does not overlap with one of the at least one enabling period directly after the one of the at least one timing pulse, an output period of a subsequent one of the at least one timing pulse will be adjusted;
• and
• an on-off control circuit, electrically coupled to the carrier frequency generation circuit, the edge detection circuit and the timing pulse generation circuit, and configured to control the carrier frequency generation circuit to output a carrier frequency signal according to the at least one rising signal, and control the carrier frequency generation circuit to stop outputting the carrier frequency signal according to the at least one timing pulse.

A modulation signal generation method implemented with an isolation integrated circuit, wherein the isolation integrated circuit comprises a carrier frequency generation circuit, a carrier frequency control circuit and a modulation circuit, and the modulation signal generation method comprises:

• detecting, by the carrier frequency control circuit, at least one enabling period and at least one disabling period of an input signal;
• during the at least one enabling period, controlling, by the carrier frequency control circuit, the carrier frequency generation circuit to output a carrier frequency signal;
• during the at least one disabling period, controlling, by the carrier frequency control circuit, the carrier frequency generation circuit to stop outputting the carrier frequency signal in an output period of at least one timing pulse, wherein the at least one timing pulse is generated in response to detection of entering the at least one disabling period, and when an output period of one of the at least one timing pulse does not overlap with one of the at least one enabling period directly after the one of the at least one timing pulse, an output period of a subsequent one of the at least one timing pulse is adjusted;
• and
• generating, by the modulation circuit, a modulation signal according to the input signal and the carrier frequency signal.