7 Benefits of Y-Bridge

The Y-Bridge architecture is particularly advantageous in systems that require a high-voltage power stage supply—such as those powered by 2S to 4S (2-cell to 4-cell) battery configurations (typically ranging from 7V to 14V). In the TAS2781 and TAS2783, this high-voltage input is supplied through the PVDDH pin, which supports a voltage range of 4V to 24V. PVDDH can be sourced either directly from a multi-cell battery or from the output of a boost converter in single-cell (1S) battery systems. The lower-voltage rail, PVDDL (ranging from 2.7V to 5.5V), is typically derived directly from a 1S battery or from a buck converter in 2S–4S configurations.

As illustrated in Figure 7-1, using the Y-Bridge architecture significantly improves efficiency at low output levels when compared to traditional Class-D amplifiers operating solely on a fixed high-voltage supply.

Figure 7-2 demonstrates that enabling the Y-Bridge feature can lead to up to 75% reduction in power loss compared to operating without this. The extent of power savings varies depending on the application and audio content. For example, audio tracks with intermittent silence or low signal levels tend to realize greater efficiency gains than continuous high-energy content like music.

This reduction in power loss can result in up to a 20% improvement in overall battery life, with no need for additional software control or system-level changes. The Y-Bridge functionality operates automatically based on signal conditions, providing a simple yet effective method to extend battery life in portable audio devices.