**synchronous boost converter**

Does anyone know how to build a synchronous boost converter with IR2104 mosfet driver? I am a beginner and I have noooo ideaaa how to connect the circuit. The placement of inductor and capacitor especially. The boost converter is meant to step up 12V to 24V. Any help would be much appreciated.

  • \$\begingroup\$ This is not a good project for a beginner, but if you must, use Andy's schematic. Do you really need high efficiency? Do you really need to control it with the MCU? Two typical mistakes: 1) under-sizing the inductor. A little inductor that looks like a resistor, won't usually work. You need to understand the equations so your inductor current is less than the saturation current. 2) be sure to put a load on the output; open loop with no load, these can produce very high voltages and will fry your parts. \$\endgroup\$ – Mattman944 Mar 29 '20 at 17:28

Does anyone know how to build a synchronous boost converter with IR2104 mosfet driver?


Any help would be much appreciated.

It's going to look something like this: -

enter image description here

Q2 charges the inductor from the main power rail by shorting it to ground and, when Q2 releases, Q1's diode will push the stored inductor energy into the load capacitor rapidly followed by Q1 turning on properly to act synchronously.

Be careful with this - if you have Q2 active for too long, the inductor might saturate and, on some supplies you might get Q2 burning.

  • \$\begingroup\$ Thank you Sir. It now makes a whole lot of sense. However, in order to increase the output voltage, does the duty cycle has to be reduced so Q2 will have longer ON time to charge the inductor ? As I noticed whenever I increase duty cycle, the ON time of Q1 appears to be longer and ON time of Q2 is shorter. \$\endgroup\$ – Yenn Mar 30 '20 at 12:41
  • \$\begingroup\$ To increase the output voltage, the duty cycle increases but it becomes rapidly non-linear and difficult to control manually. \$\endgroup\$ – Andy aka Mar 30 '20 at 15:43

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