Design And Implementation Of A Low Voltage High Power Audio Power Amplifier

Nowadays,the consumer electronics market is booming with the development of consumption level and enhancement of living standard.The consumer' s requirement for portable electronic devices becomes higher and higher due to the market' s driving.Portable electronic devices with the characteristic of handy and variety functions are favored by people when we enjoy our lives.As one of the basic components in electronic products,the performance of the audio power amplifier(APA)directly determines the market competitiveness of this products.Thus,how to design an APA of low power consumption,high performance and small footprint has become a research hotspot.The main works of this paper are as follows:(1)The APA circuit is designed according to the design block diagram on the platform of Cadence simulation tool.The circuit modules for the APA include the main operational amplifier circuit,reference current source and bias circuit,over-temperature protection circuit and Pop-Click noise suppression circuit module.The output stage adopts class AB trans-linear loop structure,which can make a good tradeoff between total harmonic distortion and static power consumption.A reference current source circuit provides a current for a circuit which is independent with the power supply voltage and process,but positively related to temperature.The over-temperature protection circuit can prevent the chip from the permanent damage due to excessive temperature,which improves the reliability of the chip.Pop-click noise(PCN)will be generated in the operation of chip ‘ s powered on or off,and the signal transition on SHUTDOWN pin.PCN suppression circuits can be used to reduce or even eliminate PCN noise.The bias circuit is a low voltage cascode circuit structure with its input and output shorted.(2)This circuit is designed based on 5V CMOS 0.5?m DPDM technology library.This paper completed layout design,post-simulation and tape out.The simulation results indicate that the circuit can work under 2.6V-5.5V power supply voltage.Under 5V power supply voltage,the chip can output continuous average 1.25 W power with 8? load;under 3V power supply voltage,the chip can output continuous average 425 mW power with 8? load;under2.6V power supply voltage,the chip can output continuous average 300 mW power with 8?load.Under the three different power supply voltages the total harmonic distortion(THD)of the output waveform of the chip is less than 1%.Finally,a low voltage,high power,low distortion and low-power shutdown mode' s APA is realized.