Hi experts,
I have a customer who wants to use TPS3513 to implement over-current sensing, Is it possible to achieve output current 7.5A in the case of 12v output voltage? If possible, please give some directions. If not, do you have better solution?
Thanks& Best Regards
Jenny,
The TPS3513 provides overcurrent protection (OCP) for the 3.3-V, 5-V, and 12-V rails. When an over current condition appears at the OCP comparator input pins for more than 73 µs, the FPO output goes high and PGO goes low. Also, this fault condition will be latched until PSON is toggled from low-to-high or VDD is removed. The resistor connected between the RI pin and the GND pin will introduce an accurate I(ref) for the OCP function. Of course, a more accurate resistor tolerance will be better. The formula for choosing the RI resistor is V(RI)/Io(RI). The Io(RI) range is from 12.5 µA to 62.5 mA.
Following is an example on calculating OCP for the 12-V rail:
Please note: V(RI) is found in EC table = 1.15 typical, Io(RI) is found in recommended operating conditions (must be between 12.5uA and 62.5uA)
I(ref) ratio is the ratio of current sense sink current (current flowing to IS12, IS33, IS5) to the current sense setting pin source current (current flowing to RI). This ratio should be between 7.6 and 8.4.
RI = V(RI)/Io(RI) = 1.15 V/20 µA = 56 kΩ
Io(RI) x I(ref) ratio x R(IS12) = R(sense) x I(OCP_Trip)
I(OCP_Trip) = 20 µA x 8 x 560 Ω/0.01 Ω = 9.2 A
This table shows the capabilities of each over current sense input for this device
Please see the overcurrent protection section on page 6 of the datasheet for additional info. Let me know if this helps you or if you need additional support. Thanks!
-Michael
