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Gate Driver ICs Forum Discussions

User22261
Level 1
Level 1
Hello friends,

I have little confusion while designing the controller board for mosfets.

I am using 3 x IRS21867S 4A Source/Sink Gate drivers with 6 mosfets (brushless driver). How much current would be needed for this IC's regulator?

12V 1Ampere regulator would be enough? Or should we use 12A (4A x 3) regulators? That peak currents are used by bootstrap capacitor or voltage regulator's bulk capacitors?

For this uncertainty I am usually trying to use highest current output regulators but I guess not much true. What can happen if I use 100mA regulator? At past when I used low current regulators I saw some unhealthy problems at drivers.

Regards
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1 Solution
Abhilash_P
Moderator
Moderator 25 likes received 250 replies posted 250 sign-ins
Moderator
Hi,

The total current required by the gate driver circuit can be calculated as follows,

Total Power or the driver power, Pdrive= ((Qg*Fsw) + Iqd) * Vg
where,
Qg = gate charge of the MOSFET used for this application
Fsw = switching frequency
Iqd = Quiescent current (for both Vbs and Vcc )
Vg = Drive voltage.

For quiescent current values, please refer to the below image,

5245.attach


Current required by the IC's regulator, I = Pdrive/Vg.

After calculating the total current multiply it by 3 so that we can arrive at the total current.

Please refer to the following app note for more details,

https://www.infineon.com/dgdl/Infineon-Use_Gate_Charge_to_Design_the_Gate_Drive_Circuit_for_Power_MO...

Please let me know if this explanation has helped you in selecting the right regulator for your application.

Regards,
Abhilash P

View solution in original post

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1 Reply
Abhilash_P
Moderator
Moderator 25 likes received 250 replies posted 250 sign-ins
Moderator
Hi,

The total current required by the gate driver circuit can be calculated as follows,

Total Power or the driver power, Pdrive= ((Qg*Fsw) + Iqd) * Vg
where,
Qg = gate charge of the MOSFET used for this application
Fsw = switching frequency
Iqd = Quiescent current (for both Vbs and Vcc )
Vg = Drive voltage.

For quiescent current values, please refer to the below image,

5245.attach


Current required by the IC's regulator, I = Pdrive/Vg.

After calculating the total current multiply it by 3 so that we can arrive at the total current.

Please refer to the following app note for more details,

https://www.infineon.com/dgdl/Infineon-Use_Gate_Charge_to_Design_the_Gate_Drive_Circuit_for_Power_MO...

Please let me know if this explanation has helped you in selecting the right regulator for your application.

Regards,
Abhilash P
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