VNH7040AY datasheet(33/48 Pages) STMICROELECTRONICS

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VNH7040AY

Open Load detection in off-state

The Open Load (OL) detection in off-state operates when output is deactivated (it means

INA = INB = PWM = 0). Open load detection is performed by reading the MultiSense output.

External (switched) pull-up resistor has to be used and dimensioned to pull output voltage

above the maximum open load detection voltage (VOL MAX) when load is not connected.

Possible conditions are specified in Table 14.

If pull up resistor is applied over switched circuitry, it allows to detect short to VCC from

Open load.

Depending on application setup, two cases can be applied:



Half-bridge, with separate loads on OUTA and OUTB, open-load pull-up resistor RPU is

applied for each side; see example in the figure below.

Figure 19. Open load detection in off-state - configuration two half-bridges

if the device is used in half bridge configuration, the RPU value has to be:

Rpull_up

VBATTmin VOLmax

–

ILoff2

min @VOLmax



-------------------------------------------------------





Full bridge (load connected between OUTA and OUTB), only one pull-up resistor RPU

is sufficient; see example in the figure below.

VNH7040AY Fiches technique(PDF) 33 Page - STMicroelectronics