Joe Voytovich
Newbie level 6
I'm re-doing a power supply board at work that takes in 2-35V from a generator and puts out 10V. Previous version used a TI chip, but that had a max input of 6V, so we had used a linear regulator pre-stage. This got HOT at higher inputs, so on to a new design.
I'm now using an On Semi NCV5171 chip. I put this together Friday and didn't get good results. The voltage spiked up briefly to about 3V, then drifted down. After tying a 100 ohm load to the output, I noticed a little whiff of smoke but don't really know where it came from. The spec says the IC is protected from over-temp (at 180C) and over-current.
Anyway, my question is on the circuit in the spec on the boost-buck mode - the SEPIC design. The 2 inductors shown in the circuit have dots on them - one open and one filled. This would indicate that they are windings on a transformer, but the spec also mentioned inductorS used - with an S, meaning more than one, and the circuit shows 22uH on each.
If this is the case, I will need to do some more tuning on the circuit with the soft start and compensation. UGH!!!
Anyone have any experience with SEPIC-type circuits, or this chip in particular??
Thanks.
I'm now using an On Semi NCV5171 chip. I put this together Friday and didn't get good results. The voltage spiked up briefly to about 3V, then drifted down. After tying a 100 ohm load to the output, I noticed a little whiff of smoke but don't really know where it came from. The spec says the IC is protected from over-temp (at 180C) and over-current.
Anyway, my question is on the circuit in the spec on the boost-buck mode - the SEPIC design. The 2 inductors shown in the circuit have dots on them - one open and one filled. This would indicate that they are windings on a transformer, but the spec also mentioned inductorS used - with an S, meaning more than one, and the circuit shows 22uH on each.
If this is the case, I will need to do some more tuning on the circuit with the soft start and compensation. UGH!!!
Anyone have any experience with SEPIC-type circuits, or this chip in particular??
Thanks.