BTL AMPLIFIER CIRCUIT

PURPOSE:To correct unbalance without reduction in the gain of an amplifier, by feeding back only unbalance component of an output side to an input side. CONSTITUTION:An feedback signal appeared at an inverting input terminal (-) of an operational amplifier A1 is applied to a non-inverting input terminal (-) of an operational amplifier A2 for phase inversion to attain push-pull operation with the operational amplifiers A1, A2. Voltage division resistors Rc having equal resistance value are connected in series between the outputs of the operational amplifiers A1, A2. A connecting point D of the resistors Rc(output neutral point) and a connecting point B of feedback resistors Ra of equal resistance value(neutral point at feedback input) are mutually connected. Thus, when an unbalanced signal component appears at the point D, this unbalanced component is applied to the inverting input of the operational amplifier, a negative feedback with almost 100% is applied, and the unbalanced output waveform is corrected.