help on a synchronous buck converter

[Sanda Ranaivo]

Hi everybody,

I'm working on a synchronous buck converter.
I use an IR2104 to control both Mosfets 1 and 2 (with arduino).
It worked very well by charging a battery OR by feeding a load (Fig1).
Then after, I created another terminal block to separate the battery and the load (Fig2).

I put a Mosfet3 (order directely by arduino) to connect or disconnect the load according to the voltage level of the battery.

And that's where I encountered a problem that I cannot understand at the moment.
As soon as I turn on the converter, the (6) VS, (7) HO and (8) VB terminals of the IR2104 are burned and the Mosfet1 is heating up. View attachment 45777 View attachment 45778

 

[Harald Kapp]

Pictures 2 and 3 show as hardly readable (almost black). Please try again and upload clear pictures.

 

[Sanda Ranaivo]

Pictures 2 and 3 show as hardly readable (almost black). Please try again and upload clear pictures.

I've already done it

 

[Alec_t]

Show us how you have all the components connected; particularly the IR2104.
Layout can be important. Is the circuit on a pcb or on a breadboard?
What is the FET switching frequency?

 

[Sanda Ranaivo]

Mosfet1 : HO (7)
Mosfet2: LO (5)
Vpv + : Vcc (1)
Vpv - : COM (4)
The switching frequency is 31 kHz