Battery charging controller for solar applications

Posted By : Nat Bowers
Battery charging controller for solar applications

Linear Technology have announced a new synchronous buck-boost battery charging controller for lead acid and Lithium batteries, the LT8490. Featuring automatic maximum power point tracking, temperature compensation, and many selectable constant-current constant-voltage charging profiles, the LT8490 is ideal for charging a variety of Lithium or lead acid chemistry types, including sealed lead acid, gel cells and flooded cells.

Operating from a wide 6V to 80V input voltage range (above, below or equal to the regulated battery float voltage), the LT8490 provides all charge terminations onboard. This eliminates the need for software or firmware and therefore also reduces design cycle time. Producing a 1.3V to 80V battery float voltage output using a single inductor with 4-switch synchronous rectification, the new battery charging controller can charge currents as high as 10A, dependant on the choice of external FETs.

Incorporating an MPPT circuit enabling a sweep of the full operating range of a solar panel, the LT8490 finds the true maximum power point of the solar panel. Even in the presence of local maxima points caused by partial shading of the panel, the LT8490 will operate at that point while using a dithering technique to quickly track changes in the local maximum power point. Using this method, the LT8490 can fully realise the power generated by a solar panel even in non-ideal operating environments.

While STATUS and FAULT pins can be used to drive LED indicator lamps, automatic temperature compensation of the battery charge voltage is performed by sensing an external thermistor on the battery. An appropriate resistor divider allows for selection of a charging time scale, while charging current limits can be adjusted by changing as few as 1 or 2 resistors. Other features of the device include input and charge current limit pins, a 3.3V regulated LDO output, status pins and a synchronizable fixed switching frequency.

Supplied in a 64-pin 7 mm x 11 mm x 0.75 mm QFN package, the LT8490 is available now with 1,000-piece pricing starting at $10.35 (USD) each. The device is offered in both E and I grades which are guaranteed for operation from -40°C to 125°C.


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Vietnam International Defense & Security Exhibition 2020
4th March 2020
Vietnam National Convention Center, Hanoi