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I know the IR2101 from reading all the other post is good for using two N-channel MOSFETs. It also states it has to be fed a square wave/PWM signal to get the bootstrapping to work correctly.

I was wondering if I could just use the low-side driver to drive one N-channel MOSFET. Would this still need a pulsing signal or can I just supply the LIN input with a 5 V signal? Would I need to ground VS? I have these IR2101 in stock and would like to use them.

IR2101

Trying this:

enter image description here

JRE
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mScientist
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1 Answers1

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There are two drivers on this chip. You can use both of them if you use them for driving the low side.

If Vss and Com are on GND, and Vb and Vcc on the positive rail, then you can use each of them as a low-side driver. In this case the upper driver does not need a bootstrap-capacitor.

JRE
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MikroPower
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  • VB and VCC go to 5v or to my 12V for the mosfets? The low side and logic fixed supply is throwing me. – mScientist Mar 13 '23 at 20:22
  • This is what I am trying. Couldn't insert picture here so edited the original question. – mScientist Mar 13 '23 at 20:31
  • VB and VCC going to 12V (max. 20V) as gate-driver voltage. Vb and Vcc to Ground. If the voltage level on Hin or Lin is higher than 3 Volt, then it is recognised as high. If the input voltage is lower as 0.8V it is a low. – MikroPower Mar 13 '23 at 20:33
  • I know it is overkill but my mosfet is actually logic level. I do have others that are not that I can play with. – mScientist Mar 13 '23 at 20:34
  • This will work, but R1 can be 0 Ohm (or 10 Ohm on every gate if you use several MSOFETS in parallel). R2 should be around 100k Ohm or bigger. If you simply want to drive the MOSFET, then you could use a NPN-transistor. Collector on the gate, Emitter to GND and a 10k pullup from +12V to the Gate, 10k Ohm from the I/O-Pin to the base of the transistor. – MikroPower Mar 13 '23 at 20:40
  • If I disconnect the line out of pin 5 LO and just measure there I am not getting any change at all. – mScientist Mar 13 '23 at 20:53
  • If you pull Lin over 3V you should get a high (12V), if you apply GND to Lin, then you get a Low (0V). What do you want to do exactly? Only activating the LED or use PWM what you get from a microcontroller (or NE555) to adjust the brightness ? – MikroPower Mar 13 '23 at 21:24
  • Right now I am just trying to get an LED to light. I have taken out the mosfet and resistors past the pin 5 connection and I am just testing the IR2101 itself and checking the voltage at pin 5. I get 0V no matter if I put 5V on LIN or not. This will hopefully, eventually run a brushed dc motor. – mScientist Mar 13 '23 at 21:32
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    Datasheet: "Gate drive supply range from 10 to 20V" + "Low side and logic fixed supply voltage: min. 10V" - This means 5V are not enough. Use 12V instead for Vcc (and VB). – MikroPower Mar 13 '23 at 21:38
  • That was it!! Thanks! – mScientist Mar 13 '23 at 21:48