28-V, Dual-/Single-Input Battery Chargers Sense Loads

Battery detection and overvoltage-protected outputs are features of the MAX8844/MAX8845 linear lithium-ion battery chargers. These 28-V, dual-/ single-input devices enhance flexibility by providing resistor-adjustable fast-charge and top-off current thresholds. To further increase flexibility, an auto-booting assistant circuit distinguishes input sources and battery connection, and also provides an enable signal for system booting. The MAX8844/MAX8845 are suited for space-constrained applications such as cell phones and smart phones. The MAX8844 has two overvoltage-protected low-dropout outputs for supplying low-voltage-rated USB or charger inputs, while the MAX8845 has a single overvoltage-protected low-dropout output. This integration eliminates the need for external overvoltage-protection ICs. Both devices integrate a battery-pack detection circuit that disables the charger when the battery pack is absent. The MAX8844 is packaged in a 3-mm x 3-mm, 14-pin TDFN, while the MAX8845 is available in a 3-mm x 3-mm, 12-pin TQFN package. Prices start at $1.42 each in lots of 1000. Evaluation kits are available to speed designs. MAXIM INTEGRATED PRODUCTS, Sunnyvale, CA. (800) 998-8800.