ZHCSHF4J May 2004 – January 2018 TPS51116
PRODUCTION DATA.
In order to provide both good accuracy and cost effective solution, TPS51116 supports both of external resistor sensing and MOSFET RDS(on) sensing. For resistor sensing scheme, an appropriate current sensing resistor should be connected between the source terminal of the low-side MOSFET and PGND. CS pin is connected to the MOSFET source terminal node. The inductor current is monitored by the voltage between PGND pin and CS pin. For RDS(on) sensing scheme, CS pin should be connected to V5IN (PWP), or V5FILT (RGE) through the trip voltage setting resistor, RTRIP. In this scheme, CS terminal sinks 10-μA ITRIP current and the trip level is set to the voltage across the RTRIP. The inductor current is monitored by the voltage between PGND pin and LL pin so that LL pin should be connected to the drain terminal of the low-side MOSFET. ITRIP has 4500ppm/°C temperature slope to compensate the temperature dependency of the RDS(on). In either scheme, PGND is used as the positive current sensing node so that PGND should be connected to the proper current sensing device, i.e. the sense resistor or the source terminal of the low-side MOSFET.