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TLE9185QX & TLE9185QX V33: Why are the drain-source overvoltage thresholds individually configurable high-side and low-sides of the same half-bridge?

TLE9185QX & TLE9185QX V33: Why are the drain-source overvoltage thresholds individually configurable high-side and low-sides of the same half-bridge?

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TLE9185QX & TLE9185QX V33: Why are the drain-source overvoltage thresholds individually configurable high-side and low-sides of the same half-bridge?

In some applications, a current measurement is required for each half-bridges. This measurement has done inserting a shunt resistor between the source of the low-side and the common SL pin of the MOSFET driver.

The drain-source overvoltage of the low-side monitors the VSHx - VSL where VSHx is the phase voltage of the considered half-bridge.

In general the MOSFETs used for one half-bridge (high-side and low-side) are symmetrical.

The individual configuration of the drain-source overvoltage (DSOV) threshold of the high-side (HS)  and of the low-side (LS) enables the compensation of the shunt resistor inserted at the low-side.

 

For example:

  • the nominal Rdson of the HS and LS is 5 mOhm
  • the resistance of the shunt resistor inserted in the LS path is 5 mOhm

Selecting DSOV threshold for LS = 2 x DSOV threshold for HS allows the same trigger current for detection of HS DSOV and LS DSOV.

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