Abstract: A control circuit and method are provided for a flyback converter converting an input voltage to an output voltage, to compensate for an entry point of a burst mode of the flyback converter, so that the entry point is not affected by the input voltage, and audible noise resulted from a higher input voltage is reduced without impacting the light load efficiency of the flyback converter.

Abstract: An oscillator generates a clock signal according to a voltage, a current and a capacitance, and a frequency jitter circuit and method use a random number to modulate the voltage, the current or the capacitance, or a count value to modulate the capacitance, to jitter the frequency of the clock signal.

Abstract: An oscillator generates a clock signal according to a voltage, a current and a capacitance, and a frequency jitter circuit and method use a random number to modulate the voltage, the current or the capacitance, or a count value to modulate the capacitance, to jitter the frequency of the clock signal.

Abstract: A high voltage H-bridge driver circuit has a high voltage terminal and a floating node to be connected with a high side switch therebetween. When turning on the high side switch, a high voltage offset detection circuit detects a voltage related to the voltage at the floating node for triggering a zero voltage switching signal.

Abstract: A power-factor-improving circuit and method for an offline converter block the DC component and obtain the AC component of an input voltage of the offline converter. The AC component is superpositioned onto a DC bias signal to generate a dimming signal for the offline converter to adjust an output current of the offline converter. The offline converter has a high power factor due to the dimming signal with the AC component of the input voltage. In addition, the average of the dimming signal is determined by the DC bias signal, hence the output current can be precisely controlled according to the DC bias signal.