SLVSH95A July 2024 – September 2025 TPS546C25
PRODUCTION DATA
TPS546C25 device uses a zero-crossing (ZC) circuit to perform the zero inductor current detection during skip-mode operation. The ZC threshold is set to a small negative value before the low-side MOSFET is turned off, entering discontinuous conduction mode (DCM) operation. After entering DCM, the ZC threshold hysteresis increases the threshold to a small positive value after entering DCM. As a result, the device delivers better light-load efficiency.
When the load current increases enough such that the device exits DCM, the ZC circuit must detect 16 consecutive cycles of negative inductor current below the ZC threshold before returning to DCM. Only one cycle without ZC detection is required to exit DCM.
During Soft-start (61h) TON_RISE the ZC circuit is always disabled and the TPS546C25 starts up in FCCM operation. If 16 consecutive cycles of negative inductor current are detected after (61h) TON_RISE completes, the TPS546C25 can enter DCM operation if FCCM mode is not selected by pin-programming or (D1h) SYS_CFG_USER1 programming.