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UCC27200: Looking for a buffer type driver that can be added after the high side driver sharing floating node and bootstrap node.

Part Number: UCC27200
Other Parts Discussed in Thread: ABS, LMG1210, LMG1020

Hi, I'm working on wireless power transfer system.

We are using GaN device (EPC 2111) and its input capacitance is almost 250p F.

I'm looking for a buffer or driver that can be used right after our high side driver to drive our target GaN device.

Output of our high side driver swings 0~20V with the bootstrap voltage(VBOOT) and floating node(VSW) that are swing 5~20V and 0~15V for each.

Voltage difference between VBOOT and VSW is 5V and a cap are between them.

PWM input signal will be 6.78MHz, therefore, I need a buffer or driver that can operated in 6.78MHz. 

I found UCC27200 device can accept the output of my circuit as an input, but I couldn't find the maximum frequency range it can operate.

Can it be used in the 6.78MHz system?

I want to use another high side driver, but we need to keep our design in use.

If there's any other suggestion of devices, please tell me.

Thank you for your precious time to read my issue.

Jae-Jin

  • Hi Jae-Jin,

    Thanks for reaching out and welcome to e2e!

    For driving a high-side GaN FET you can use a half-bridge driver which includes the level shifter needed for the high-side drive, or you can use a floating low-side driver with signal isolation instead.

    For a lower cost and smaller size solution LMG1210 has been specially designed to drive a GaN half-bridge well above 6.78MHz while protecting the GaN gate below the 6V abs max. Let me know if you have any questions designing LMG1210 into your wireless power application.

    Thanks,

  • Hello Jeff,

    Thank you for your suggestion.

    I think it looks great for my case.

    To be sure, I want to ask you once more..

    If I use LMG1210, I'm thinking of using low side driver right after my high side.

    Since the high side has bootstrap and floating node with 0~20V swing output, can I use low side of LMG1210 as an extra driver after the high side?

    I checked the datasheet that it has really strong drive capacity. 

    My target GaN device has 250pF input capacitance and the input pulse signal of my driver will be operate in 170kHz and 6.78MHz.

    I checked the datasheet, but to be sure, I want to ask you one more time...

    On the other hand, I was looking at the LMG1020 low side driver device.

    Every characteristics of it look fine for my case, except for the driving capacity.

    I need to drive GaN device with an input capacitance around 250pF. 

    If you know about LMG1020, will it be about to drive the GaN device?

    Best Regards,

    Jae-Jin Lee

  • Hi Jae-Jin,

    Thanks for the update,

    LMG1020 can be used to drive GaN or MOSFETs. Let me know if you have any other questions on this.

    LMG1210 has a PWM input mode that uses one PWM pin to create 2 outputs with dead-time. LMG1210 has also a independent input mode (IIM) which allows you to use LI and HI inputs with overlapping outputs with no dead-time required. For more details, see section 6.8 of the LMG1210 datasheet ()

    Thanks,