SLUS964D NOVEMBER 2009 – March 2018 TPS40303 , TPS40304 , TPS40305
PRODUCTION DATA.
The TPS40304 uses the negative drop across the low-side FET at the end of the OFF time to measure the inductor current. Allowing for 30% over maximum load and 20% rise in RDS(on)Q1 for self-heating, the voltage drop across the low-side FET at current limit is given by Equation 32.
The TPS40304 internal temperature coefficient helps compensate for the MOSFET RDS(on) temperature coefficient, so the current limit programming resistor is selected by Equation 33.