DC-DC Multi-output Buck Converter (3.3V/5V/9V/12V) (DFR1015)

Support Product Questions
1

This is a placeholder topic for “DC-DC Multi-output Buck Converter (3.3V/5V/9V/12V)” comments.

This DC-DC Step Down Voltage Converter steps down voltage from 7.5V~30V to 3.3V/5V/9V/12V(default to 5V), which can be selected by short-circuiting the…

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2

Can you please help me with a concrete circuit connection for this component? I want to go from 11v lipo to 9v regulated, but I’ve killed two of them trying.

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11V input for a 9V output is right at the margin for this device, and it may not work correctly. Your 11V supply will likely dip somewhat under load, so you might be operating outside the specs. I don’t know whether operating it like this would kill it, or just stop it working.

To wire it you will disconnect the default 5V link and connect the 9V link instead. Make sure only one link is connected at any one time. Then connect your 11V supply to the input side, ensuring you have got + and - the right way around, and connect your load to the output side, again ensuring you have got the + and - the right way around. That’s all there is to it.

Getting the input + and - the wrong way around is certainly one way it could be killed (I can’t see a reverse polarity protection diode). Significantly overloading the output (for instance, accidentally short-circuiting the output terminals) is a possibility, but I suspect the controller chip has overload protection and would just shut down.

Can you show a diagram of how you had it wired when it died?

4

Thanks so much for your answer.

Alt dfr1015 connections
Alt dfr1015 connections2224×1668 440 KB

These are the two methods I can think of. I tried the top way. Assuming the two holes top left are both negative terminals. It makes me wonder if they are in fact independent inputs. The silk screen is just saying which of the two pins is negative.

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The bottom diagram will not work :face_with_raised_eyebrow: In fact, it will trip the LiPo circuitry.

The top diagram is correct +/+, -/- at both ends.

Can you confirm that the 5V link is correctly disconnected and the 9V link connected instead.

Note that the rated output of 2.5A is optimistic. It comes from the manufacturer’s specification for the chip, and assumes a very specific mounting for the chip, including heat sinks. I don’t know whether or not this module fully complies. But, in any case, if the chip is overloaded it should just shut down. Are you sure that you really killed the other modules, or is it possible that they just shut down through being overloaded?

Otherwise it might be that they simply don’t work well enough with that load and only a 2V differential. If you are driving a motor then it would be worth using the 5V link rather than the 9V, at least to confirm the setup.

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Hey @Mark85861,

I have just tested one of these boards on our test bench. I did not solder for the 9V output and simply tested at 5V output. I lowered the input voltage starting at 7V (2V differential similar to your setup). Some things to note:

  • The output voltage was consistent at 5-4.98V from an input voltage of 7V - 5.6V
  • At 5.5V, the output voltage began dropping more quickly (unsurprising but useful).
  • This was performed using a bench power supply, this obviously have differing output characteristics than a LiPo
  • This was measured with no load at the output.

Have you tried measuring the voltage at the output when no load is applied?

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Hi Mark

If you had both links made that could possibly do some damage. Only one link at a time should be made
Cheers Bob

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There isn’t a link for the default 5v. There are only jumper pads to select the other 3 voltages.

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Hi Aaron
Straight from DFRobot web site
Instruction

This module outputs 5V by default and the corresponding 5V solder pad is short-circuited. To output other voltages, for instance, 3.3V, please disconnect the 5V pad and short-circuit the 3.3V solder pad.

Note: Since this is a step-down converter, the input voltage should be larger than the output, and it works better with a voltage difference of 2V and above.

Link to the page

Cheers Bob

And copied straight from the Core page

image
image883×556 88.8 KB

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11

Hi All
This thread has gone very quiet.

Did anyone (Mark???) get a definite result or do we do the usual and wait forever for nothing.
Cheers Bob

12

Hi Robert,

The 5V pads are on the front of the board and the other 3 are on the rear. Only one should be shorted at a time to prevent damage to the board.

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Hi Jack.
Yes, if you care to look above I brought that to Aaron’s attention 13 days ago.
I was just wondering if Mark had some success.
But oh well. About par for the course I suppose.
Cheers Bob

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