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My question is how can I close the loop with no load condition of my buck-boost converter, by using peak limiting current mode control? Is the bleeder resistor needed or is it possible just to close the loop and have constant voltage, whilst having no actual load? If you can provide an example of doing just that, that would be cool.

enter image description here This is the system I'm having (\$R_1 \to \infty\$). This picture is generated by me.

Thanks to all in advance.

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My question is how can I close the loop with no load condition of my buck-boost converter, by using peak limiting current mode control? Is the bleeder resistor needed or is it possible just to close the loop and have constant voltage, whilst having no actual load?

It's exactly the same argument for a boost converter. No need to complicate the question by using a buck-boost or inverting example. In other words, if you don't have some form of light load on a boost converter output AND, you can't get down to a duty cycle of dead-zero then, the output voltage will continue to rise until the output capacitor or diode or MOSFET breaks down.

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  • \$\begingroup\$ So I cannot "compensate" for this situation by using just plain peak limiting current mode control? \$\endgroup\$
    – usernamenenad
    Commented Jun 12 at 14:46
  • \$\begingroup\$ Any current though the inductor will result in an unwanted energy transfer to the output over time. \$\endgroup\$
    – Andy aka
    Commented Jun 12 at 16:54
  • \$\begingroup\$ You could enter a hysteretic PFM mode at light loads where the switching frequency drops to maintain the output voltage in regulation, but it's no longer peak current control at that point. Many controllers can do this automatically. \$\endgroup\$
    – John D
    Commented Jun 12 at 18:35

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