JAJSJH9C April 2023 – October 2024 TPS62874-Q1 , TPS62875-Q1 , TPS62876-Q1 , TPS62877-Q1
PRODMIX
Figure 8-15 shows a functional block diagram of the power-good function in a secondary device. During initialization, the device presets FF2, which pulls down the PG pin and forces the devices in a stack to operate in DCM. When the device completes the internal start-up sequence, the device resets FF2, which turns off Q1. In a stacked configuration all devices share the same PG signal, and therefore the PG pin stays low until all devices in the stack have completed the start-up. When that happens, FF1 is set and the converters operate in CCM. FF1 and FF2 are preset such that DCM is allowed each time the converter is disabled, either by the EN pin, EN bit, thermal shutdown or UVLO.