LM1875 DC current of the negative feedback circuit BTL

Posted on Dec 11, 2010

DC current of negative feedback BTL circuit shown in Figure 2, the abolition of the standard BTL circuit C12, C22, the circuit of the DC; resistor R16 and R26 are sampling resi

LM1875 DC current of the negative feedback circuit BTL
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stor, current feedback signal by R15, R16, R25, R26, respectively, into the amplifier A1, the inverting input of A2, R13, R14, R15, R16 resistance determines the amplifier gain. Experiment with the circuit in Figure 2, the power-off anyway with the input signal, the output of the DC output has not, and there is no static output noise, only a slight boot horn A pair of sound, no noise when turned off the speaker can be heard. Experiments found that such input circuit is very stable, even in high volume, or static input terminal unplugging and plugging in the circuit will not be self-excited. Capacitor C11 a great impact on the sound quality, remove this capacitor, the eyes immediately light up, become clear and delicate treble, bass and elastic strength. DC of current negative feedback circuit BTL inherits the advantages of direct current negative feedback circuit OCL sound quality, distortion is further reduced, the output power is increased to three times the original, up to 60 watts or more, to overcome its switch speaker has an impact there hum sound and disadvantages of static, the LM1875 is ideal circuit optimization.

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