MCP34063 in buck/boost topology

bojankoce · ‎2022-01-26

Hello, everyone.

I need to generate a stable 12V to supply my cooling fan (current consumption not over 200-300mA). The input voltage is in the range of 10V to 26V. Consequently, some buck/boost topology will be needed.

I came across the MCP34063 module. It is clear from the datasheet that it can work in the following topologies:

Step-up
Step-down
Voltage inverting

I wonder if there is a possibility to configure MCP3406 to work in both step-up and step-down modes and generate stable 12V at the output for the input voltages in a range from 10V to 26V?

Thank you very much guys for your time and efforts. Your help is really appreciated.

Looking forward to reading from you.

Sincerely,

Bojan.

Peter BENSCH · ‎2022-01-26

Well, 300mA at 12V doesn't sound like much, but 10...26V is a wide range to cover.

I did a quick calculation: Ipk would already be at the upper edge at 10V, even more at 26V, so the MC34063 is not suitable for this application.

Unfortunately, I can't recommend any other device from ST's portfolio with which you can easily set this up.

Good luck in finding the right device!

Regards

/Peter

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Peter BENSCH · ‎2022-01-26

Yes, you can build a buck-boost regulator with the MC34063, but this requires both an additional power switch (classic pnp bipolar or possibly p-channel FET) and a second Schottky. However, it would have to be checked first whether this can work up to your desired 26V.

However, it is a fact that the MC34063 was developed almost 30 years ago and therefore still works with a very low switching frequency, which makes the passive components (L, C) quite large, bulky and expensive.

Would this effort be worthwhile for you?

Regards

/Peter

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bojankoce · ‎2022-01-26

Hello, @Peter BENSCH .

Thanks for the prompt reply. I am generally interested in something small and simple that will generate me 12V at the output for the input voltages in a range from 10 to 26V.

Not happy to hear that MCP34063 requires bulky passive components.

Is there any better module (simple, cheap, with minimal external components) from ST that could help me achieve the goal? As I said, current consumption is not critical. It will not be more than 300mA @12V.

Cheers!

Peter BENSCH · ‎2022-01-26

Well, 300mA at 12V doesn't sound like much, but 10...26V is a wide range to cover.

I did a quick calculation: Ipk would already be at the upper edge at 10V, even more at 26V, so the MC34063 is not suitable for this application.

Unfortunately, I can't recommend any other device from ST's portfolio with which you can easily set this up.

Good luck in finding the right device!

Regards

/Peter

In order to give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.

bojankoce · ‎2022-01-26

Thanks for the clarifications, @Peter BENSCH ! Really appreciate your help.

Cheers! :clinking_beer_mugs:

Peter BENSCH · ‎2022-01-26

If the problem is resolved, please mark this topic as answered by selecting Select as best. This will help other users find that answer faster.

Good luck!

/Peter

In order to give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.

bojankoce · ‎2022-01-26

The problem is not resolved for me but it is at least clear that MCP34063 is not an appropriate part. 😀