A speaker amplifier circuit is being designed, voice chip output + audio power amplifier LM4890 (1W output), and the output current is more than 100mA.
LM4890 is ti's 1W audio power amplifier.
If you want to achieve 5W output later, the current will be even greater.
Because of the power supply, I want to build the power amplifier here with an ordinary op amp. But I checked the manual of the op amp and the output current is all tens of mA.
Is it not possible to build this kind of audio rear amplifier circuit with a general-purpose op amp? (For example, the voltage range is 40V, the output power is 5W/8 ohm, and the current is 5/20=250mA when calculated according to the 20V voltage)
Bowen Posted on September 29, 2020
You have to look at his THD parameter, you can't come casually.
Lloyd Posted on September 29, 2020
LM4890 is a BTL power amplifier, analog circuit, the advantage of BTL is high power under low voltage. To increase power, you must not use ordinary low-current operational amplifiers. When there is no top requirement for sound quality, why not use Class D power amplifier chips? Class D has low heat and high output power.
Donna Posted on September 29, 2020
If you want to reduce the cost, you can directly replace the domestic audio power amplifier chip.
