AN4213 datasheet(28/42 Pages) STMICROELECTRONICS

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Driving optimization

AN4213

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DocID023984 Rev 2

Driving optimization

A driving network optimization has been performed with the main purpose to have thermal

and dynamic behavior of the devices compliant to the features of the system.

5.1

Power MOSFET circuit optimization

Here below is the electrical schematic concerning the driving circuit of the Power MOSFET.

Figure 18. Driving network optimization

An RC snubber network, R = 180

Ω and C

=47 pF, has been inserted in order to avoid a

voltage spike and voltage oscillation across the Power MOSFET during its turn-off.

Furthermore, limiting the rise slope of the Power MOSFET voltage,

ΔV

ΔT, the cross

between voltage and current is also reduced resulting in less switching losses during turn-

off. On the other hand, a too high value involves a peak on the current during turn-on. So a

right trade-off has to be found in order to balance the switching losses during turn-off and

turn-on and to have the best performance of the device.

AM17332v1

Csn

Rsense

AN4213 Datasheet(PDF) 28 Page - STMicroelectronics