L99MH98 datasheet(34/147 Pages) STMICROELECTRONICS

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Stage 1

The first stage occurs when VGS < Vstep1xl, x = 1...8, in case of switch ON of the external MOSFETs or VGS

< Vstep1xh, x = 1...8, in case of switch OFF of the external MOSFETs. In the first stage the gate drive

current will be Ionx (ISTEP1_CONFx, x = 1...8, register), x = 1...8, in cases of switch ON and Ioffx

(ISTEP1_CONFx, x = 1...8, register), x = 1...8, in case of switch OFF of the external MOSFETs.

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Stage 2

The second stage occurs when Vstep1xh < VGS < Vstep2xh, x = 1...8, in case of switch OFF of the external

MOSFETs or Vstep1xl < VGS < Vstep2xl, x = 1...8, in case of switch ON of the external MOSFETs. In this

second stage the gate drive current can be programmed differently in the switch ON and switch OFF

phases. In case of switch ON, the Ionx, x = 1...8, is set programming the ISTEP2_CONFx, x = 1...8,

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Stage 3

The third stage occurs when VGS > Vstep2xl, x = 1...8, in case of switch ON of the external MOSFETs or

VGS > Vstep2xh, x = 1...8, in case of switch OFF of the external MOSFETs. In the third stage the gate drive

current will be Ionx (ISTEP3_CONFx, x = 1...8, register), x = 1...8, in cases of switch ON and Ioffx

(ISTEP3_CONFx, x = 1...8, register), x = 1...8, in case of switch OFF of the external MOSFETs.

Figure 18. Power ON/OFF steps for gate drivers

Drain

Gate

VStep2

VStep1

VMiller

IStep2

IStep1

IStep3

L99MH98

Gates driver

DS14611 - Rev 3

page 34/147

L99MH98 Scheda tecnica(PDF) 34 Page - STMicroelectronics