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I want to use the IR2133 to drive a mosfet rectifier. I have setup as in the circuit below

enter image description here

The probelm is (take first high side fet as example) that the signal that appears on HO1 is exactly the same as whats on VS1. The gate voltage VGS should should be VS1 + turn on voltage(30V) when the PWM signal on HIN1 is activated. The PWM has no effect on the signal whatsoever whether disconnected or not.

Do perhaps some of the other pins need to be set to enable this functionality and should this behaviour be expected in this configuration?

Edit 1:

Below is a plot of the PWM signal and the (low voltage) AC signal taken from HO1 and is the same as the input signal.

enter image description here

Thanks.

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  • \$\begingroup\$ They are not MOSFETs; they are IGBTs. If you applied 30 volts Vgs most mosfets would be damaged. Are you really feeding the bridge supply AC? \$\endgroup\$ – Andy aka May 2 '18 at 12:37
  • \$\begingroup\$ How are you bootstrapping it? Show oscillograms! \$\endgroup\$ – winny May 2 '18 at 12:41
  • \$\begingroup\$ @Andy aka Schematic is taken from the data sheet but same setup for mosfets. Yes I am feeding the bridge supply AC as I want to rectify the signal. \$\endgroup\$ – MXG123 May 2 '18 at 12:50
  • \$\begingroup\$ @winny I believe the dio.de and capacitor is used for bootstrapping but I'm not sure if it works right \$\endgroup\$ – MXG123 May 2 '18 at 12:51
  • \$\begingroup\$ Me neither, that's why I'm asking you to take oscillograms. I bet you two bucks your duty cycle is too high or switch frequency too low. \$\endgroup\$ – winny May 2 '18 at 13:42
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With an AC supply connected directly to your Vs pins how do you avoid this: -

enter image description here

  • VB1,2,3 cannot go more than 0.3 volts negative relative to GND
  • VS1,2,3 cannot go more than 25 volts below VB1,2,3

Personally I think you need to swap load and bridge power connections.

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  • \$\begingroup\$ As stated in the datasheet " All voltage parameters are absolute voltages referenced to COM". So if your in the negative half cycle (say -600) so as VS and VB alternate they should be ok??? \$\endgroup\$ – MXG123 May 2 '18 at 14:53
  • \$\begingroup\$ @MXG123 you can't take VS1,2, or 3 below 0.3 volts negative. It doesn't mean ABS(x) if that's what you meant? \$\endgroup\$ – Andy aka May 2 '18 at 14:59
  • \$\begingroup\$ Maybe this device is not suitable for my needs. Is it possible to raise the source voltage Vthreshold above to turn on. I can connect the source to gate with a resistor so they are equal and put a dc source in series. However putting a dc source in series is tricky to do. \$\endgroup\$ – MXG123 May 2 '18 at 15:24
  • \$\begingroup\$ Is the question finished now or do you have further comments that need clarifying? \$\endgroup\$ – Andy aka Jun 6 '18 at 15:06

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