Bridge-tied-load (BTL) configuration in an amplifier is basically a H-network with the loud-speaker as the “bridge” between two active valve or switcher. This configuration allow a full alternating current signal to be produced at the load (loudspeaker) without a transformer or a symmetric power supply. Here are some benefits of BTL configuration:
- No need large capacitor for DC blocking (decoupling)
- No need for symmetric power supply for push-pull drive
- No need for transformer for push-pull drive
- Higher “output power” to “supply voltage” ratio
Using integrated circuit, such BTL circuitry is presented in a compact form, and a TDA7056 is one example of this. It’s a mono output amplifier contained in a 9 pin medium power package. This device is designed for general audio amplifier such as battery-powered amplifier, portable mono recorders, radios, or television. TDA7056 has many features such as low power consumption, short circuit proof, and ESD protection on all pins. For ultimate compactness, neglecting the power supply filtering caps and input loading stabilizer resistor, there would be no external components is needed to build a fully functional amplifier circuit! Power-on-click suppression system make this device also no switch on/off clicks. Finally, TDA7056 has good stability.