high side driver of ir2110 in buck configuration

[Aamir_Sheikh]

i am trying to make a buck converter by using ir2110's high side driver to drive a Irf 540n, in a buck configuration.
the problems that i am facing are
a) output voltage is erratic, without the lc configuration it works kinda fine, with output voltage swinging between Vs(10 volts) and duty*vin, but with lc configuration it jumps up to 21-22 volts om a 10% duty cycle.

b) response is not continuous, i.e bootstrap capacitor takes time to charge and pulses on gate appear and the disappear for a few moments then reappear.


operating frequency does not matter, tried it on frequency range of 5 to 20 khz, dont have the schematic but it is the same as the one drawn on page 17 on the following app note
**broken link removed**

lc network, 89uh, 220uf

and one with 489uh, 470uf*3 in which response is continuous but op voltage is 22 volts on a 10 % duty cycle.

R1=22k, Cb=470uf, Vin=24 v, vout=14-16v, D3 12v zener, Vcc=12volt, vdd=5volt

have a opto isolator between driver and MC.


and why does Vs of ir2110 does not get pulled down to ground during off time?

 

[kabeer02]

try and change your bootstrap cap to 10-22uf and tell me the result.

 

[Aamir_Sheikh]

try and change your bootstrap cap to 10-22uf and tell me the result.

same thing as before, now just more rapid,with pulses on gate appearing and disappearing quickly

 

[Robby Jonsen]

same thing as before, now just more rapid,with pulses on gate appearing and disappearing quickly

I have the same problem like you aamir. Did you solved the problem? Please let me know how, thank you.

 

[Orson Cart]

Hello there, you need a bottom side device to turn on to provide a charge path for the cap on the high side for the high side gate drive, without this the load provides this path which is problematic as you are finding.

 

[mrinalmani]

Decrease the value of load resistance to near about minimum. Recheck results. If there is an improvement, then for sure you need an auxiliary charging switch for the bootstrap capacitor.

 

[Aamir_Sheikh]

tioned somewhere in an application note of International rectifier that involved using the main supply

Hello there, you need a bottom side device to turn on to provide a charge path for the cap on the high side for the high side gate drive, without this the load provides this path which is problematic as you are finding.

Orson cart you are right, i ended up using half-bridge driver, in synchronous configuration.