SLVSFT8F February 2023 – December 2023 TPS7H1111-SEP , TPS7H1111-SP
PRODUCTION DATA
Refer to the PDF data sheet for device specific package drawings
As described in Section 8.3.9, the SS_SET pins are connected together so that each TPS7H1111 internal error amplifier sees the same voltage. A single RSET resistor may be utilized of half the normal value (since there is now 200 μA of current through the resistor). Two CSS capacitors should be utilized (or one of twice the normal value) in order to ensure equivalent start-up time.
A 5 mΩ Rballast resistor was utilized. The board resistance from the output of one device to the common VOUT rail of both devices was assumed to be significantly less than the ballast resistor and was therefore not considered to be a significant factor in calculating the total ballast resistance. This ballast resistor was selected to achieve a reasonable tradeoff between accurate current sharing and minimizing voltage drop across the resistance. If desired, the output voltage of each device could be set marginally higher to account for a voltage drop at a given current.
Section 8.3.9 shows how to calculate the worst current sharing mismatch using the output offset voltage. Additional details are in the following section showing how results are measured better than expected.