Stereo Power Amplifier Circuit using LA4440

Stereo amplifiers are characterized by the presence of two output and input channels. The weak input signal will be amplified and the output channels’ output power will be increased. This circuit has the ability to provide 6 watts of power to speakers.

LA4440 Audio Amplifier

This design utilizes the stereo chip IC LA4440, which has stereo input and output channels built-in. The LA4440 may operate between 12V and 18V. In addition, this chip can give 6W of power to each output channel while in stereo mode. This amplifier can provide a signal gain of around 53.5dB.

Working on Stereo Power Amplifier

IN1 and IN2 are stereo input channels through which the weak audio signal will be supplied. The capacitors C10 and C1 eliminate DC components from the signal. R3 and R4 will function as a volume control. The LA4440 IC pins 2 and 6 link to the internal audio amplifier stage. This stage’s amplified output is sent to the driver amplifier, which is then followed by the output stage. The signal to be amplified will be extracted from output pins 12 and 10.

Capacitor C1 is a feedback capacitor; it determines the amplifier’s lower cutoff frequency. Reducing the value of the capacitor will increase the input signal’s cutoff frequency.

Capacitor C9 connected to pin 5 functions as a ripple filter. The capacitor C3 is attached to Pin 13 as a bootstrap capacitor. This will supply bias voltage to the output stage, allowing the output signal to attain rail-to-rail voltage.

The coupling capacitor between output pins 12 and 10 is utilized to filter DC noise from the signal. The output signal is prevented from oscillating by an RC (C5R1 and C6R2) network. This will allow LA4440 to provide a consistent output signal.


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