SLOSE86B july 2022 – july 2023 TAS2781
PRODUCTION DATA
The TAS2781 can operate with both PVDDL and PVDDH as supplies or with only PVDDH or PVDDL as supply. The table below shows different power supply modes of operation depending on the user need.
Supply Power Mode | Output Switching Mode | Supply Condition | PVDDL Mode | Device Configurations | Use Case and Device Functionality | |
---|---|---|---|---|---|---|
PWR_MODE0 | High Power on PVDDH | PVDDH>PVDDL | External | PVDDL_MODE=0 CDS_MODE[1:0]=10 | PVDDH is the only supply used to deliver output power. | |
PWR_MODE1 | Y Bridge - High Power on PVDDL | PVDDH | External | PVDDL_MODE=0 CDS_MODE[1:0]=00 | PVDDL is used to deliver output power based on level and headroom configured. When audio signal crosses a programmed threshold Class-D output is switched over PVDDH. | |
PWR_MODE2 | Y Bridge - Low Power on PVDDL | PVDDH | Internal | PVDDL_MODE=1 CDS_MODE[1:0]=11 | PVDDH is the only supply. PVDDL is delivered by an internal LDO and used to supply at signals close to idle channel levels. When audio signal levels crosses -100dBFS (default), Class-D output switches to PVDDH. | |
PWR_MODE3 | PVDDL | PVDDL | External | PVDDL_MODE=0 CDS_MODE[1:0]=01 | The device can be forced to work out of a low power rail mode of operation. For example this can be used for a low power ultrasonic chirp when audio is not played. |
When PVDDL is external (PWR_MODE0, PWR_MODE1), if PVDDH falls below (PVDDL + 2.5 V) level, the Y-bridge will stop switching between supplies and will remain on the PVDDH supply.
In PWR_MODE2 user needs to ensure that PVDDH supply level is at least 2.5 V above the PVDDL voltage generated internally in order to take advantage of Y bridge mode of operation. To enable voltage protection the under voltage threshold of PVDDH supply should be set above 7.3 V by using register bits PVDD_UVLO[5:0]. This will ensure that, with an internally generated PVDDL of 4.8 V, PVDDH supply is at least 2.5 V higher than PVDDL.