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I developed a half-bridge buck converter, I did all the steps, from the converter calculations, such as accommodating the copper in the appropriate ferrite core, wire gauge diameter, etc., my project was for a buck converter operating at 50 kHz to vary the output voltage from 12-22 V with an input of 24 V with a maximum current of 3 A.

I used the gate driver IR2104 + MOSFET's IRF840 in the circuit, the oscillation signal is generated by an ESP32 (for prototyping purposes), I calculated the minimum output capacitance in order to filter the ripple so that my ripple did not exceed 1% at maximum current. I placed a much larger capacitor than calculated to have a good clearance... But this strange ripple (which obviously has the same frequency as my gate driver's switching frequency, as seen in the oscilloscope images below) continues to torment me. I can't remove it, I know that breadboard mounting is not suitable due to ground loops, parasitic inductances, etc., etc., but should this ripple be so evident, even with these assembly characteristics?

I am new to the development of switching sources in power electronics, I only used to buy the most suitable commercial source and was ready to assemble the other circuits. I think I lack the insights of someone who already has experience in the field of power electronics.

P.S: I made a small mistake in the schematic, the IR2104 power is 12 V, which comes from the 7812 linear regulator. In the schematic, I made this little confusion and put the IR2104 power at 24 V

Below we have images showing:

The developed circuit diagram.

Images of the circuit assembled on a breadboard.

Oscilloscope with AC coupling showing output ripple when I have a duty cycle of 10% and a load of 30 mA.

Oscilloscope with AC coupling showing output ripple when I have 90% duty cycle and 500 mA load.

Schematic of the half bridge buck converter circuit developed.

circuit on the breadboard with oscilloscope measurement tip and other circuit stages that are not of interest at the moment

Output ripple with 10% duty cycle and a 30mA load

Oscilloscope showing output ripple when I have 90% duty cycle and 500mA load.

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  • \$\begingroup\$ Looks like inductance of your long wires before the output capacitor \$\endgroup\$
    – TQQQ
    Commented Jun 27 at 0:55
  • \$\begingroup\$ If i am correct, you need to add ceramic capacitor (1-10 uF) and try to use a wider or shorter wire (or both). \$\endgroup\$
    – TQQQ
    Commented Jun 27 at 1:33
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    \$\begingroup\$ Breadboard and scope ground lead likely to be huge contributors. Design a proper PCB with good decoupling and layout of the critical high dI/dt paths and incorporate test points that allow the use of the short scope ground spring. \$\endgroup\$
    – Unimportant
    Commented Jun 27 at 5:01
  • \$\begingroup\$ Does this answer your question? Gate and Drain ringing on a highside MOSFET Driver \$\endgroup\$
    – Andy aka
    Commented Jun 27 at 9:03
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    \$\begingroup\$ Breadboard and discrete switchmode converters are mutually exclusive. You need to design a PCB for it with ground plane. \$\endgroup\$
    – winny
    Commented Jun 27 at 10:33

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