JAJSOQ2 December 2023 TPS1200-Q1
ADVANCE INFORMATION
The CTMR programs the short-circuit protection delay (tSC) and auto-retry time (tRETRY). Once the voltage across CS+ and CS– exceeds the set point, the CTMR starts charging with 80-μA pull-up current.
After CTMR charges to V(TMR_SC), PD pulls low to SRC and FLT asserts low providing warning on impending FET turn OFF. Post this event, the auto-retry behavior starts. The CTMR capacitor starts discharging with 2.5-uA pulldown current. After the voltage reaches V(TMR_LOW) level, the capacitor starts charging with 2.2-uA pullup. After 32 charging-discharging cycles of CTMR the FET turns ON back and FLT de-asserts.
The device retry time (tRETRY) is based on CTMR for the first time as per Equation 7.
Use Equation 6 to calculate the CTMR capacitor to be connected across TMR and GND.
Where,
ITMR is internal pull-up current of 80-μA.
tSC is desired short-circuit response time.
Leave TMR floating for fastest short-circuit response time.
If the short-circuit pulse duration is below tSC then the FET remains ON and CTMR gets discharged using internal pull down switch.