Tiny Power Amplifier With LM4952

LM4952 It is not always necessary to have a high power audio amplifier. It is enough to power the small speakers with much less power. The presented amplifier meets this condition. It has a power of 2 × 3 W / 4 V, and additionally allows electronic volume control. LM4952

The module is based on an LM4952 system comprising two power amplifier channels and a DC-regulated electronic gain control circuit.

LM4952 schematic diagram

The power supplied by the manufacturer for a 12V power supply is LM4952 2X3W The system allows (according to the application note) a power supply of 9.6V … 16 volts, but it is already working well above 7 volts. This makes it possible to supply, for example, with 2-3 connected Li-On or Li-Po cells in series.

The input signal from the LM4952 IN terminal through the coupling capacitors C1 and C2 is fed to U1. Once the CE2 and CE3 constant gain and isolation are available on the OUT connector. The power supply to the circuit is fed to the DC coupler, where after filtration (capacitors C4, CE3) supplies U1. The “adjustable” Zener diode U2 is responsible for maintaining a stable voltage of 3 V on the SHDN output for U1 switching on and supplying the control voltage circuit for the volume potentiometer. The use of additional stabilization prevents the system from fluctuating volume associated with changes in power supply voltage, for example, when powered by a battery. Resistor R1 determines current U2, divider R2 / R3 output voltage. The adjusting potentiometer is connected to the VOLUME connector.

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