LM74722-Q1: What's the gate pin peak source current

Wiky Liao

Part Number: LM74722-Q1

Hi Team,

May I know the gate pin peak source current of LM74722-Q1? Our customer will use total 4 MOSFET to conduct total 420A current, the source capacity will guide us the rough turn on time of MOSFET. Thanks.

over 2 years ago

0 Praveen GD over 2 years ago

TI__Guru 57737 points

Hi Wiky,

The Gate pin source current for LM74722-Q1 can be calculated using the tGATE_ON(DLY) parameter specified in the datasheet.

As you can see it takes 0.8 us for the LM74722-Q1 to charge a 10nF gate cap to a voltage > 5V. Using I = C* dv/dt equation, you can back calculate the Igate.

0 Wiky Liao over 2 years ago in reply to Praveen GD

TI__Intellectual 1550 points

Hi Praveen,

Thanks for your guidance. Per these two parameter, the Igate will be about 62.5~136mA level.

+1 Praveen GD over 2 years ago in reply to Wiky Liao

TI__Guru 57737 points

Hi Wiky,

The tGATE_ON(DLY) includes the 'fixed internal delay to turn ON the GATE' + 'Time taken for the Gate-A voltage to reach 5V'.

The 'fixed internal delay to turn ON the GATE' will be pretty much constant. Hence for for higher gate cap, you will see the 'tGATE_ON(DLY)' will be relatively faster.

0 Wiky Liao over 2 years ago in reply to Praveen GD

TI__Intellectual 1550 points

Hi Praveen,

Thanks for pointing out the delay time. I try to set the delay time to a constant value, and 30nF capacitor charging time will be 3 times of 10nF, so Igate will be 333mA finally. 10nF charging time is about 0.15us.

0 Praveen GD over 2 years ago in reply to Wiky Liao

TI__Guru 57737 points

Hi Wiky,

Yes, your understanding is correct.

0 Wiky Liao over 2 years ago in reply to Praveen GD

TI__Intellectual 1550 points

Hi Praveen,

Understand. Thanks for your help.

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LM74722-Q1: What's the gate pin peak source current