Highly-integrated high-voltage multi-chemistry battery charger controller

A new highly-integrated, high-voltage multi-chemistry synchronous step-down battery charger controller, the LTC4013 has been introduced by Linear Technology. With a wide input voltage range that spans up to 60V, the LTC4013 uses temperature-compensated 3- and 4-stage charge algorithms to efficiently charge 12V and 24V lead-acid batteries. Alternatively, the LTC4013 will charge a multi-cell 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 optimization 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, ruggedized notebooks/tablet computers, plus remote powered communication and telemetry systems. The LTC4013 utilizes N-channel MOSFETs for high-efficiency charging, and features a wide battery charge voltage range of 0V 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 equalization. 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 synchronize 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 analog information about charge current. The LTC4013 is housed in a compact 28-lead 4mm x 5mm QFN package with an exposed metal pad for high thermal performance. E- and I-grade devices offer operation from –40C to 125C.