L9908 datasheet(9/152 Pages) STMICROELECTRONICS

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Figure 4. 14 V pulse scenario - applicative condition

The negative peak voltage reached during such a transition can be described by the following formula:

SHSnpeak =Vd_peak+ LPAR_TOTdILOADtfall+ Rsℎunt+RPAR_TOTIload

(1)

SHSnpeak ≈ LPAR_TOTdILOADtfall

(2)

The first term Vd_peak is the transient peak voltage of the LS FET body diode, the second is due to transient

response of the parasitic inductances between SHS_n and GND while the third is related to path resistance drop.

Given the maximum current conducted, the application shall limit the maximum undershoot peak voltage by

minimizing the ratio:

LPAR_TOTtfall

(3)

(Ex: if Iload = 100 A then LPAR_TOT = 4 nH then tfall must be kept higher than 33 ns)

The above-mentioned considerations also apply to SHS_n positive pulse which takes place when the inverter is

working in generator mode.

2.1.2

Parametrical Operating Range

Within these operating ranges the part operates as specified and without parameter deviations. The device may

show parameters deviation if parametrical operating conditions are exceeded.

Once taken beyond the operative ratings and returned back within, the part will recover with no damage or

degradation (provided that AMR range is not exceeded). All analog and digital voltages are related to the potential

at signal ground SGND. All currents are assumed to be positive when current flows into the pin.

L9908

Absolute maximum ratings

DS13546 - Rev 5

page 9/152

L9908 数据表(PDF) 9 Page - STMicroelectronics