Shenzhen Sts Microelectronics Co., Ltd.

Solomon Ng

Gang Zha

Wen Li Luo

An audio amplifier device includes a power supply having an output for providing a supply voltage, a voltage divider connected to the output of the power supply for providing a divided supply voltage, and an audio amplifier that further includes a supply voltage rejection circuit. The audio amplifier has a first input for receiving an input audio signal, a second input for receiving the supply voltage, a third input for receiving a supply voltage rejection signal for the supply voltage rejection circuit, and an output for providing an output audio signal. A power-off noise suppression circuit has a first input for receiving the divided supply voltage and an output for providing the supply voltage rejection signal. The power-off noise suppression circuit sets the supply voltage rejection signal equal to the divided supply voltage during power-off of the power supply so that a rate of decrease of the supply voltage is greater than a rate of decrease of the supply voltage rejection signal for reducing noise in the output audio signal during the power-off.

Power-off noise suppression circuit and associated methods for an audio amplifier device

A circuit structure for performing current amplification. The circuit structure may be standardized as a current amplifier cell such that many types of applications requiring current amplification may be created. The basic amplifier cell, which may accept voltage or current sources as an input signal, produces two identical output signals which may be used for feedback or serve as input to additional amplifier stages. This simple structure may be extended to perform current amplification with variable gain or AC or DC voltage-to-current conversion through the use of appropriately selected resistive elements.

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Hong Kong, China

Solomon Ng