An efficient solar-powered solution
Linear Technology has developed a simple, innovative high voltage buck-boost charging controller IC specifically for solar applications, one which requires neither software nor firmware development, thus greatly reducing time-to-market.
The LT8490, shown in Figure 4, is a synchronous buck-boost battery charging controller for lead acid and Lithium batteries, featuring automatic maximum power point tracking and temperature compensation. The device operates from input voltages above, below or equal to the regulated battery float voltage. The device’s full-featured battery charger offers many selectable constant-current constant-voltage (CC-CV) charging profiles, making it ideal for charging a variety of Lithium or lead acid chemistry types, including sealed lead acid, gel cells and flooded cells. All charge termination algorithms are provided onchip, eliminating the need for software or firmware development, thus reducing design cycle time.
The device operates over a wide 6 V to 80 V input voltage range and can produce a 1.3 V to 80 V battery float voltage output using a single inductor with 4-switch synchronous rectification. The device is capable of charging currents as high as 10 A depending on the choice of external FETs. The LT8490’s MPPT circuit enables a sweep of the full operating range of a solar panel, finding the true maximum power point, even in the presence of local maxima points caused by partial shading of the panel. Once the true maximum power