SLOSE75B February 2022 – March 2023 TAS2780
PRODUCTION DATA
The TAS2780 Class-D output uses a Y-Bridge configuration to improve efficiency during playback. The LVS (Section 8.4.2.5) is internally used to select between the PVDD and VBAT1S supplies. This feature is enabled by setting CDS_MODE[1:0] bits to 2'b00 when both PVDD and VBAT1S are supplied externally to the device. In this case the VBAT1S rail must be capable of delivering power (up to 1 W).
If not configured to Y-bridge mode the device will use only the selected supply for Class-D output even if clipping would occur. The device can operate using only PVDD to supply Class-D output. In this configuration the VBAT1S can be provided from external supply (register bit VBAT1S_MODE=0) or generated by an internal LDO (register bit VBAT1S_MODE=1). In this case CDS_MODE[1:0] bits should be set to 2'b10.
The TAS2780 Y-Bridge with low power on VBAT1S can be used to switch to the VBAT1S rail only at very low power when close to idle. This will reduce the Class-D output swing when near idle and limit the current requirements of the VBAT1S supply. Set the CDS_MODE[1:0] register to 2'b11 for this mode.
See Section 11.1 for details on programming the power mode of operation.
When in Y-Bridge mode, if the PVDD falls below (VBAT1S + 2.5 V) level the Y-bridge will stop switching between supplies and will remain on the PVDD supply.