VNH7070AS datasheet(23/38 Pages) STMICROELECTRONICS

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VNH7070AS

Application information

Figure 17. Suggested PCB layout

Note:

PCB layout recommendation:

Optimized connection (short) between Drain LSD and Source HSD

Optimized GNDa and GNDb connection (symmetric connection)

3.1

Reverse battery protection

Three possible solutions can be considered:

•

A Schottky diode D connected to VCC pin

•

An N-channel MOSFET connected to the GND pin

•

A P-channel MOSFET connected to the VCC pin

In case the reverse battery protection is not present, the device sustains no more than -15 A

because of the two Body diodes of the Power MOSFETs. Additionally, in reverse battery

condition the I/Os of the device is pulled down to the VCC line (approximately -1.5 V).

Series resistor must be inserted to limit the current sunk from the microcontroller I/Os. If

IRmax is the maximum target reverse current through microcontroller I/Os, series resistor is:

3.2

OFF-state open-load detection – External circuitry

dimensioning

The detection of an open-load in off state requires an external circuitry to be connected

between Output and VBATT.

For the detection it is necessary to put one network on each leg in case of Half Bridge

operation or one network on one of the output in case of full bridge (see Table 13: Off-state

-truth table).

The external circuitry is made up by an external pull-up resistor Rpull_up connecting the

output to a positive supply voltage VPU (VBatt).

IO s

–

Rmax

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