VN7140AS12 datasheet(26/39 Pages) STMICROELECTRONICS

26 / 39 page

Application information

VN7140AS12

26/39

DocID029756 Rev 2

Normal operation (channel ON, no fault, SEn active)

While device is operating in normal conditions (no fault intervention), VSENSE calculation can

be done using simple equations

Current provided by Multisense output: ISENSE = IOUT/K

Voltage on RSENSE: VSENSE = RSENSE · ISENSE = RSENSE · IOUT/K

Where:



VSENSE is voltage measurable on RSENSE resistor



ISENSE is current provided from Multisense pin in current output mode



IOUT is current flowing through output



K factor represents the ratio between PowerMOS cells and SenseMOS cells; its

spread includes geometric factor spread, current sense amplifier offset and process

parameters spread of the overall circuitry the specifying ratio between IOUT and ISENSE.

Failure flag indication

In case of power limitation/overtemperature, the fault is indicated by the Multisense pin

which i

s switched to a “current limited” voltage source, VSENSEH.

In any case, the current sourced by the Multisense in this condition is limited to ISENSEH.

The typical behavior in case of overload or hard short circuit is shown in Waveforms

section.

Figure 34: Analogue HSD

– open-load detection in off-state

VN7140AS12 Datasheet(PDF) 26 Page - STMicroelectronics