LM7310 datasheet(16/44 Pages) TI

16 / 44 page

Note

1. It's recommended to choose RIMON such that VIMON < 1.5 V at the maximum DC load current.

2. It's also recommended to add a zener on the IMON pin to clamp the voltage below 1.8 V during

high current transients.

7.3.6 Reverse Current Protection

The device functions like an ideal diode and blocks reverse current flow from OUT to IN under all conditions. The

device has integrated back-to-back MOSFETs connected in a common drain configuration. The voltage drop

between the IN and OUT pins is constantly monitored and the gate drive of the blocking FET (BFET) is adjusted

as needed to regulate the forward voltage drop at VFWD. This closed loop regulation scheme enables graceful

turn off of the MOSFET during a reverse current event and ensures there's no DC reverse current flow.

The device also uses a conventional comparator (VREVTH) based reverse blocking mechanism to provide fast

response to transient reverse currents.Once the device enters reverse current blocking condition, it waits for the

(VIN - VOUT) forward drop to exceed the VFWDTH before it performs a fast recovery to reach full forward

conduction state. This provides sufficient hysterisis to prevent supply noise or ripple from affecting the reverse

current blocking response. The recovery from reverse current blocking is very fast (tSWRCB). This ensures

minimum supply droop which is helpful in applications such as power MUX/ORing.

OUT

FWD

IN - VOUT

BFET regulation mode

BFET full conduction mode

BFET turned OFF

0 V

VFWD

VREVTH

VFWTH

Figure 7-7. Reverse Current Blocking Response

The waveforms below illustrate the reverse current blocking performance in various scenarios.

During fast voltage step at output (e.g. hot-plug), the fast comparator based reverse blocking mechanism

ensures minimum jump/glitch on the input rail.

LM7310

SNOSDC0 – OCTOBER 2020

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LM7310 Datasheet(PDF) 16 Page - Texas Instruments