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Request for LM1876 single supply bridged circuit

Other Parts Discussed in Thread: LM1876


Need to design a single supply (20 to 36 V) bridged amp to drive a 4 ohm loudspeaker. Expected power output is approx 40 Watts RMS with 24 Volts single supply.


Ramakrishna Rao

  • Hi Rao-san,

    Thank you for choosing LM1876 on you design. To get 40W into 4 ohms load in BTL connection, the voltage across the load is about 18Vpk. This means the current flow into 4 ohms load is about 4.5 Amps pk. Unfortunately LM1876 doesn't have capability to run 4.5 Amps. It is 3.5 Amps typ and 2.9 amps min. So we will recommend to take LM4780.  LM4780 has enough output current capability to run more than 4.5 Amps. With 24V ingle supply and 4 ohms load, you will get 40W. Please try it.

    Best regards