Synchronous step-down battery charger features MPPT circuitry

Alternatively, the LTC4013 will charge a multicell Lithium-based battery stack with float voltages near to the input supply. Mode pins define the float voltage and charge algorithm. Charge current is precision regulated to ±5% and programmable with a single resistor up to 20A (depending on the selection of external components).

The LTC4013 features user-adjustable Maximum Power Point Tracking (MPPT) circuitry that enables simple power optimisation in the case of power-limited sources such as solar panels. The MPPT open-circuit method corrects for panel temperature changes without the inconvenience of adding a solar panel temperature sensor. Applications include portable medical instruments, monitoring equipment, battery backup systems, industrial handhelds, industrial lighting, military equipment, ruggedised notebooks/tablet computers, plus remote powered communication and telemetry systems.

The LTC4013 utilises N-channel MOSFETs for high efficiency charging, and features a wide battery charge voltage range of 0 to 60V. The main charging features of the product can be adjusted using pin-strap configurations and programming resistors, enabling the user to select between several predefined charging algorithms depending on battery chemistry. For lead-acid battery types such as vented, sealed and gel, the LTC4013 supports multiple charging stages, including float, programmable-timed absorption and equalisation.

Each charge voltage includes adjustable temperature compensation. For Li-Ion/Polymer cells, the device offers a constant-current/constant-voltage charging algorithm. The SYNC input provides the ability to synchronise the switching frequency to an external clock to avoid noise in a particular frequency range or to target noise filters to a specific frequency. Other product features include an external input MOSFET driver (INFET) to avoid battery discharge during an input supply short, two open-drain status pins, and an ISMON pin that provides analogue information about charge current.

The LTC4013 is housed in a compact 28-lead 4x5mm QFN package with an exposed metal pad for excellent thermal performance. E- and I-grade devices are guaranteed for operation from –40 to 125°C. 1,000-piece pricing starts at $3.95 each for the E-grade and devices are available from stock.