Each diode is in parallel with the corresponding internal bootstrap diode. An external series resistor, smaller than

RDS_diode, can be still used together with each diode to reduce the maximum charging current and helps to limit

the voltage drop on the REG12 pin. The maximum drop on the CREG12 capacitor occurs when the three bootstrap

capacitors must be recharged and no series resistor is used with the external diodes. This drop can be

approximated as:

Equation 4

(4)

ΔVCREG12≈VREG12∙ 3∙CBOOT

CREG12+3∙CBOOT

Figure 11. External bootstrap diode configuration

12 V

LDO reg

REG12

C

REG12

C

BOOTx

BOOTx

OUTx

x3 bootstrap circuitries

5.2.2

Externally provided gate driver’s supply voltage

It is possible to provide externally the supply voltage for the gate driving circuitry directly, bypassing the integrated

regulator and shorting VS and REG12 pins together.

Important:

Using this configuration the consumption is partially reduced in standby mode.

Figure 12. 12 V LDO supply voltage externally provided

VS

12 V

LDO Reg

REG12

VCC

CREG12

100 nF

STDRIVE101

12 V LDO linear regulator

DS13472 - Rev 1

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