Power amplifier ICs commonly used in TV circuits and their functional characteristics

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1. The model is complicated, and there are differences between Chinese and foreign designs. Domestic manufacturers still have a long way to go.

When comparing the main technical data of these power amplifier ICs, it's often difficult to distinguish between many models, even if there are minor differences. This indicates that the audio circuit design in TVs lacks proper optimization and continuity. In audio systems where empirical data plays a key role, design inheritance is a crucial aspect. Maintaining this continuity can significantly reduce unnecessary R&D costs and also bring cost savings in production and material management.

2. Most models have low power output.

In early TVs (up to 51cm), power amplifiers were mainly based on mono 2VV. Today, at least a two-channel design is used, with each channel reaching more than 6W of power output.

3. Many designs are specifically tailored for TV applications.

For example, Panasonic’s AN52XX series and Sanyo’s LA426X series are designed for TV use. The AN5250 even integrates IF amplification and frequency discrimination circuits. Some newer TVs now use universally designed audio power amplifier ICs. This shift is due to increased audio requirements and reduced costs from technological advancements, leading to more versatile functions in these ICs.

4. The power supply is mostly single-ended, and circuit configurations include OTL, OCL, and BTL circuits are becoming more common.

The audio section of a TV doesn’t require high power. Using a dual power supply increases circuit complexity. To avoid large output capacitors, OCL requires a dual power supply, while BTL can use a single power supply and eliminate the need for an output capacitor. Although output capacitors have limited impact on sound quality, large capacitors take up significant space on the PCB and are not very effective in TV circuits. BTL circuits, although requiring more complex circuitry compared to OCL under similar conditions, are easier to implement in integrated circuits, so BTL-based power amplifier ICs are gradually gaining popularity.

5. Class AB and Class C amplifiers are commonly used, while Class D amplifiers are still less common.

Due to the demand for compact size, heat dissipation, energy efficiency, and environmental protection, the application of Class D amplifiers is expected to grow significantly in the future.

6. On-chip integrated sound control functions are gradually being reduced.

Many power amplifier ICs integrate DC electronic volume control, and some have basic tone control features. However, as audio system control requirements increase—such as advanced tone control, balance, subwoofer, surround sound, and environmental effects—some models use dedicated sound control circuits. Others may support features not available in domestic TV signals. While specialized ICs offer more functions, they also increase system complexity and cost. As these features become more widely accepted, it is likely that they will be integrated into small signal processing ICs in TVs. Therefore, the integration of audio amplifier ICs is gradually decreasing.