high side mosfet driving with IR2110 - problem

high side mosfet driving

Dear all,

Attached is a circuit to drive a single high side driver, the circuit works fine when the load is not connected to the parallel capacitor (470uF/400V). but when the capacitor is connected in parallel to the load the IR2110 is burnt,

can any one advise on this.

Many thanks

high side mosfet driving

A freewheeling diode must be present to suppress negative output voltages when opening the switch. Furthermore, without a low-side switch, there must be at least a resistive load to charge the bootstrap capacitor.

I also don't see the purpose of the diode-inductor series circuit.

Re: high side mosfet driving

FvM said:

A freewheeling diode must be present to suppress negative output voltages when opening the switch. Furthermore, without a low-side switch, there must be at least a resistive load to charge the bootstrap capacitor.

I also don't see the purpose of the diode-inductor series circuit.

Click to expand...

hi,

I have attached the the circuit with the free wheeling diode.... please ignore the diode - inductor series circuit...

do i need to add a lowside switch in order to make it work, because here i dont really need the low side swicth..

Re: high side mosfet driving

Without a low-side switch, the circuit can only be started with zero output voltage. It needs some auxilary circuit to charge the bootstrap capacitor. I think, IRF has specials drivers for single high-side switches.

Re: high side mosfet driving

Hi,

As for single side driver, i think if i use IR2117 single side driver, would that solve my problem.

Re: high side mosfet driving

if your duty cycle is less than 70%, use an isolation transformer instead

Re: high side mosfet driving

u mean a drive trafo circuit , to drive the high side mosfet

Added after 1 hours 19 minutes:

Dear All,

I have attached some changes, because as earlier the bootstrap capacitor is not charged..


At the beginning of the initial cycle during startup, the bottom-side MOSFET switch is turned on. This pulls the Vs pin to ground, which charges up the bootstrap capacitor to through bootstrap diode .

When the high-side driver is enabled during the next half cycle, the driver can turn on the high-side mosfet, and the Vs pin will rise up to VIN (0-300 V) .

Then the cycle repeats itself—high mosfet is switched off, bottom mosfet turned back on, the Vs pin is pulled down to ground, and bootstrap capacitor is recharged.

Re: high side mosfet driving

Yes use a driver transformer for the high side and use a totempole on the low side driver, by the way what is your switching frequency?

Re: high side mosfet driving

This can work, but the IRF level shifting drivers surely have superior switching behaviour. I guess, you never used these devices.

Re: high side mosfet driving

Dear All,

I ahve noticed the circuit that i have attached works fine when the 470uF / 450 V capacitor is not added.

when i add the 470uF/450 V capacitor i have noticed that the Vin most to most goes up to 20V and beyond that the IR2110 burns.

Can anyone advise on this

high side mosfet driving

Vin most to most goes up to 20V

Click to expand...

I don't understand, which voltage is meant exactly. Generally, there may be a circuit layout problem. Do you have any measures to keep the inductor current within acceptables limits during turn-on.

If you mean the input voltage ripple: There must be of course an effective bypass capacitor!

As another point, I fear that the output inductance is at least one order of magnitude too low! 22 uH means maximum of 13.5 A/us current slope at the output inductor. Would require MHz switching frequency for moderate ripple currents.

If you originally intended to operate the inductor with non-continuous current flow, you can't use a low side switch and need a different MOSFET driver or an auxilary circuit for the high side driver supply.

Re: high side mosfet driving

very sorry for not stating it clearly...

The Vin that i meant is actually the high voltage ( 0 - 300V)

I notice if i don't add the 470uf /450V capacitor, then the circuit works fine, but when i add the 470uf/450V capacitor and increase the high voltage starting from 0V when i increase up almost 20V the circuit works fine, switching is ok but when i increase the high voltage to 20V and above the IR2110 IC burns ...and i have changed few IC's due to this.

Added after 2 hours 16 minutes:

FvM said:

As another point, I fear that the output inductance is at least one order of magnitude too low! 22 uH means maximum of 13.5 A/us current slope at the output inductor. Would require MHz switching frequency for moderate ripple currents.

If you originally intended to operate the inductor with non-continuous current flow, you can't use a low side switch and need a different MOSFET driver or an auxilary circuit for the high side driver supply.

Click to expand...

Actually can you please explain on why i can't use alow side switch and need a different MOSFET driver.

so u mean to say that switching at 20Khz frequency is not enough for a 22uH inductor.

Click to expand...