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Gate Driver ICs Forum Discussions

User20927
Level 1
Level 1
I use IR2110S.

I use only the high side to drive the motor.
Sometimes the motor will not run.

The schematic and oscilloscope waveform are attached.
VBS is measured with a differential probe.

The output of HO gradually drops and reaches 0V. (Cannot be seen on the scale of the attached image)
VBS suddenly becomes 0V.


I have some ideas:
• The duty ratio of the input to HIN is about 98%.
• The motor may have an effect.

I'm in trouble because the problem isn't solved.
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Srivatsa
Moderator
Moderator 5 sign-ins 50 replies posted 25 solutions authored
Moderator
As VBS is going down to 0 V the HO output is switching off. The recharging of the bootstrap capacitor is load dependent and 98% duty cycle is not helping.

You can test with an isolated 12 V power supply across C162 and verify that this is root cause and then try with lower duty cycle (25%)

If you plan to use only the high side, you can look at high-side only gate drivers such as IR2117/8, IR2125 or IR2127.

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Srivatsa
Moderator
Moderator 5 sign-ins 50 replies posted 25 solutions authored
Moderator
As VBS is going down to 0 V the HO output is switching off. The recharging of the bootstrap capacitor is load dependent and 98% duty cycle is not helping.

You can test with an isolated 12 V power supply across C162 and verify that this is root cause and then try with lower duty cycle (25%)

If you plan to use only the high side, you can look at high-side only gate drivers such as IR2117/8, IR2125 or IR2127.
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