LA4550
is a 2 channel audio frequency power amplifier IC specifically designed for
radio, tape-recorder use etc. The features of LA4550 are low quiescent current,
built in 2 channels for stereo and bridge mode operation, excellent ripple
rejection, good channel separation, negligible pop-up noise during power
ON/OFF. The LA4550 can be operated from 12 Vdc and can deliver 4W of output
power into an 8 ohm speaker.
Description.
In
this circuit LA4550 is wired in bridge mode. For stereo application, two
identical amplifier modes have to be built according to the circuit diagram. In
the circuit capacitors C6 and C3 provides feedback and their value determines
the lower cut-off frequency. Capacitors C1 and C7 are meant for bootstrapping.
Branch C2, R1 and C8, R3 are meant for preventing oscillations, and so the high
frequency stability of the LA4550 audio amplifier gets improved. Capacitors C9
and C10 are meant for coupling the speaker to the IC. C4 is a ripple filtering
capacitor while C11 and C12 are meant for power supply filtering. Audio input
can be applied to pin 8 of the IC with respect to the ground.
Circuit diagram.
Notes.
• Use
12 Vdc for powering the circuit.
•
Maximum possible supply voltage is 13V.
•
LA4550 requires a heat sink.
• The
package style of LA4550 is DIP 12F and suitable heat sinks are available in the
market.
• Use
8 ohm/10W as the loudspeaker.
• An
optional 10K POT connected in series to the input line can be used as the
volume control.
