VN5050AJ-E datasheet(21/31 Pages) STMICROELECTRONICS

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VN5050AJ-E

Application information

21/31

Application information

Figure 26.

Application schematic

3.1

GND protection network against reverse battery

This section provides two solutions for implementing a ground protection network against

reverse battery.

3.1.1

Solution 1: resistor in the ground line (RGND only)

This can be used with any type of load.

The following show how to dimension the RGND resistor:

RGND ≤600mV / (IS(on)max)

RGND ≥ (−VCC) / (-IGND)

where -IGND is the DC reverse ground pin current and can be found in the absolute

maximum rating section of the device datasheet.

Power dissipation in RGND (when VCC<0 during reverse battery situations) is:

PD= (-VCC)

2/ R

GND

This resistor can be shared amongst several different HSDs. Please note that the value of

this resistor should be calculated with formula (1) where IS(on)max becomes the sum of the

maximum on-state currents of the different devices.

Please note that, if the microprocessor ground is not shared by the device ground, then the

RGND will produce a shift (IS(on)max * RGND) in the input thresholds and the status output

values. This shift will vary depending on how many devices are ON in the case of several

high side drivers sharing the same RGND.

VCC

GND

OUTPUT

DGND

RGND

Dld

µC

+5V

VGND

CS_DIS

INPUT

Rprot

CURRENT SENSE

RSENSE

Rprot

Cext

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