This makes a change from the usual eBay-trash work lights that I take apart. It was given to me by the local electrical utility company to check out after it failed to take a charge. (faulty charger)
The unit has a decent set of lithium cells giving about 7.2V at 4.4Ah. The charge circuit uses a buck regulator to allow a wide voltage range to charge the cells:-
www.xlsemi.com/datasheet/XL400...
And then boosts the cell voltage to two sets of four beefy LED chips in series (about 12V total) using a boost regulator to step up the battery voltage:-
www.xlsemi.com/datasheet/XL600...
There's what looks like it could be a microcontroller or dedicated management chip, but it's not got a number on it.
The PCB is quite complex, but it allows the internal battery bank to be charged from about 10V up to 30V and drives the LED array at a constant current for its full discharge giving consistent intensity until it suddenly cuts off. I'm not keen on that sudden cut off bit, given that the guys using it are working on high voltage powerlines and equipment. But they probably have LED head torches too.
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8 дек 2017
