Electronics > Beginners
IR2110 and two low side FETs
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Alex Nikitin:

--- Quote from: 09d08 on August 22, 2018, 02:23:08 pm ---
--- Quote from: Alex Nikitin on August 22, 2018, 02:10:05 pm ---
--- Quote from: 09d08 on August 22, 2018, 12:16:55 pm ---Normally I would use a TC4427 for this application but the last one I got decided to release the magic smoke recently. Since I don't have any buffer ICs so I tried to create one with two BJTs but the result wasn't as good as the one I got with the TC4427. So should I try to improve the BJT driver or use the IR2110 without the bootstrapping capacitor and diode? I'm not really sure what changes I would have to make to the diagram given in the datasheet to make it suitable for my use case.

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 :palm:

"The BJT Driver" you've drawn will also go up in smoke... .

Cheers

Alex

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Care to explain what exactly is wrong with it?

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Just calculate the power dissipation on the NPN device when it is conducting.

Cheers

Alex
David Hess:

--- Quote from: 09d08 on August 22, 2018, 02:23:08 pm ---
--- Quote from: Alex Nikitin on August 22, 2018, 02:10:05 pm ---"The BJT Driver" you've drawn will also go up in smoke... .
--- End quote ---

Care to explain what exactly is wrong with it?
--- End quote ---

The current drawn out of the base of the PNP transistor is unlimited.  This could be corrected by moving the top of the NPN collector resistor to the base of the PNP.  A parallel resistance between the base and emitter of the PNP should also be added.

Ian.M:
If one wanted to use an IR2110 as a dual low side driver, one would strap Vs to COM and Vb to Vcc.   Operation with Vs tied to COM is explicitly permitted as that's what datasheet Figure 3. Switching Time Test Circuit simplifies to with Vs at the minimum indicated level of 0V relative to COM.
Seekonk:
Many inverter designs do the same thing and use the 2153 oscillator half bridge as two low side drivers to make simple push pull inverters. A nice one chip solution.
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