BTL type amplifier circuit diagram and characteristics

 BTL is the English abbreviation of "balanced non-output transformer". This type of power amplifier is a bridge push-pull amplifier circuit. It is also a BTL power amplifier circuit that requires no debugging, high fidelity, and low cost.

Characteristics of BTL power amplifiers

One is to use a single power supply mode

The second is to use rising edge and falling edge pulse signals to trigger

The third is to use double-terminal direct coupling output mode. The efficiency of this type of power amplifier is higher than that of OCL power amplifier, so it is widely used in new color TVs, color monitors, audio and other circuits.

BTL power amplifier circuit diagram

A typical BTL power amplifier is shown in the figure below. The power amplifier tube of the BTL power amplifier is a four-leg circuit composed of two complementary symmetrical circuits. The load RL is connected to the output ends of the two complementary symmetrical circuits and uses a direct coupling output method.

The power supply voltage VCC is added to the collectors of amplifier tubes VT1 and VT2 to power them. In the static state, since there is no signal input, the amplifier tubes VT1~VT4 are cut off, there is no voltage output, and no current flows through RL. When the positive half-cycle signal of Ui is input, VT1 and VT4 are turned on, and their collector currents form a loop from VCC through VT1, RL, VT4 to ground, forming the first half-cycle of the output signal; when the negative half-cycle signal of Ui is input, VT2 , VT3 is turned on, and their collector currents form a loop from VCC, VT2, RL, VT3 to ground, forming the negative half cycle of the output signal. In this way, a complete signal can be obtained.