For the past couple of years, I have been powering my Sony 55” LCD TV and charging laptop computers from a 12V solar system.

Both the Sony TV and the laptop computers had an input voltage of 19.5VDC. To step up the voltage from the battery, I purchased two "LTC3780 Automatic lifting pressure constant voltage step up step down 10A 130W" a.k.a. LTC3780 - High Efficiency, Synchronous, 4-Switch Buck-Boost DC-DC Converters from eBay. These boards operated from a moderately wide 5 - 36V input and had an output voltage range of 1 - 30V.

The LTC3780 has no output current limiting or Under voltage Lockout (LOUVRE) on-chip, so the designers of these modules implemented their own using a commodity LM358 Op Amp.

Within the first couple of months, I managed to blow both boards up with the same fault – a very stressed LM358 which would then kill the LTC3780 by exceeding the RUN pin’s absolute maximum voltage. More on this can be found on my wiki here.

In the end, I replaced the LTC3780 (it cost more than the boards from eBay, but helped with the root cause investigation), omitted the LM358 and used a 0603 resistor between pads of the LM358 to tie the LTC3780’s run pin high. They have operated flawlessly since, albeit without current limiting or low voltage cut-out.

But, I have always wanted to elegantly house the boards. And a wider input and output voltage range had always been appealing.