BTL Mono Amplifier With DC Volume Control Circuit

Description: This is a BTL (bridged tied load) mono amplifier with a DC volume control circuit. This circuit utilizes the TDA7052A/AT, which is suitable for monitors, TVs, and battery-operated portable radios and recorders. Unlike conventional DC volume circuits, the TDA7052A/AT does not require a coupling capacitor in its DC volume control, allowing for the maintenance of low offset voltage. Additionally, the TDA7052A/AT's DC volume control operates at low supply voltages. The BTL principle offers advantages such as a ripple frequency on the supply voltage that is twice the signal frequency and reduced peak supply current. To minimize costs, a smaller capacitor can be employed. The BTL principle is particularly beneficial in portable applications, enabling a decrease in supply voltage while simultaneously increasing output power. This amplifier achieves a maximum gain of 35.5 dB. The mute mode is activated when the DC volume control voltage falls below 0.3V. Furthermore, the circuit is equipped with thermal protection, causing the gain to decrease when the temperature reaches +150°C. [Circuit diagram source: nxp.com]

The BTL mono amplifier circuit employing the TDA7052A/AT is designed to deliver high efficiency and performance in compact audio applications. The TDA7052A/AT integrates the essential functions of an amplifier, allowing for a simplified design while eliminating the need for external coupling capacitors. This not only reduces component count but also enhances reliability by minimizing potential points of failure associated with coupling capacitors.

The operation of the amplifier is based on the BTL configuration, which effectively doubles the output voltage swing compared to a single-ended amplifier. This results in increased output power, making it particularly advantageous for battery-powered devices where maximizing power output is crucial. The BTL configuration also mitigates the ripple frequency on the supply voltage, which is beneficial for maintaining audio quality by reducing interference from power supply fluctuations.

The DC volume control feature of the TDA7052A/AT allows for precise audio level adjustments without introducing significant distortion or noise. The low supply voltage requirement further enhances the suitability of this amplifier for portable applications, where battery life and efficiency are paramount.

Thermal protection is an essential feature of this amplifier, ensuring that the device operates within safe temperature limits. When the temperature exceeds +150°C, the gain is automatically reduced to prevent damage to the circuit, thereby extending the operational lifespan and reliability of the amplifier.

In summary, the TDA7052A/AT BTL mono amplifier circuit is an innovative solution for audio amplification in portable devices, combining low voltage operation, efficient power usage, and built-in protection features to deliver high-quality audio performance.This is BTL(bridged tied load) mono amplifier with DC volume Control circuit. This circuit uses TDA7052A/AT that is suitable not only for monitors and TV but also battery fed portable radios and recorders. The difference between conventional DC volume circuits and TDA7052A/AT the DC volume control is there is no coupling capacitor is needed in TDA

7052A/AT the DC volume control to maintain the low offset voltage. Besides that, the TDA7052A/AT the DC volume control requires low supply. The advantages of BTL principle are it has the ripple`s frequency on the supply voltage is twice the signal frequency and the supply current peak is lower. This is the figure of the circuit; To save the cost, a smaller capacitor can be used. The BTL principle can be implemented in portable application that will decrease supply voltage but increases the output power.

This amplifier has maximum gain of 35. 5 dB. The mute mode is when the DC volume control voltage is below 0. 3V. This circuit also equipped with thermal protection. The gain will be decreased when temperature reach +150 C. [Circuit diagram source: nxp. com]