Analog and Power Electronics Corp.

Fu-Yuan Chen

Ming-Hung Chang

Chun-Hung Chang

Shu-Hua Wang

In a control circuit and method for a high efficiency and low EMI switching amplifier, an input signal is compared with a reference signal to generate a comparison signal, and a control signal is generated in response to the comparison signal for a driver to generate an output signal. The output signal is fed back to control the slope of the reference signal in association with an initial level set for the reference signal to provide a minimum on-time period for the output signal. Alternatively, a reference value is provided to compare with the reference signal for setting a minimum on-time period for the output signal.

Control circuit and method for a switching amplifier

In a switching amplifier for generating a pair of output signals of square waves in response to an input signal, when the input signal is zero, the first output signal has a first duty cycle and the second output signal has a second duty cycle; when the input signal is greater than zero, the first output signal has a third duty cycle varying with the input signal and the second output signal still has the second duty cycle; and when the input signal is less than zero, the first output signal has the first duty cycle and the second output signal has a fourth duty cycle varying with the input signal. The first and second duty cycles are very small but equal to each other in size, and the phase difference between the first and second output signals could range from 0 to 180 degrees.

Switching amplifier and control method thereof

In an amplifier circuit with reduced power-off transients, an amplifier is provided for receiving an input signal and a reference signal to generate an output signal therefrom when it is enabled, and the amplifier is disabled when the supply voltage to the amplifier drops down to a threshold or to a level higher than the reference signal a threshold. The output stage transistor of the amplifier is applied with a body voltage to suppress the body diode parasitic to the output stage transistor to be forward-biased.

Amplifier circuit with reduced power-off transients and method thereof

In an amplifier circuit with reduced power-on transients, an amplifier has a gain to generate an output signal from an input signal and a reference signal when it is enabled, and a control circuit generates a control signal, based on the output signal and the reference signal, to be supplied to the amplifier during a power-on event. The amplifier is enabled by the control signal when the reference signal reaches the level of the output signal.

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Alian, Taiwan

Fu-Yuan Chen