28V, single-input battery charger is smallest, safest charging solution for handhelds
(Product News, 01 Apr 2008 )
Maxim Integrated Products’ MAX8814 is the first 28V-rated, single-input charger for single-cell lithium-ion (Li+) batteries. Requiring only 4mm2 of board space, this device integrates Maxim's proprietary temperature and constant-current, constant-voltage (CCCV) regulation circuitry to eliminate overheating during fast-charging and to simplify hardware design. A robust solution, the MAX8814 features overvoltage-protection circuitry that enables it to withstand input transients up to 28V. The robustness and integration of this tiny charger make it ideal for use in cell phones, smartphones, USB applications, Bluetooth(R) devices, and other handheld equipment in which safety, charging speed, and size are of significant concern.
The high integration of the MAX8814 considerably simplifies solution implementation, while providing the best savings in both space and BOM cost. This device eliminates the need for a bulky external FET, reverse-blocking diode, current-sense resistor, and thermal-regulation circuitry. Using its CCCV circuitry, the IC intelligently controls the charging sequence from the prequalification state, through constant-current fast-charging, to the final constant-voltage charge. To enhance flexibility, the MAX8814 allows fast-charge current adjustment through an external resistor. Additionally, it features an autobooting circuit that monitors the system-booting signal and input-power status, and provides an enable signal to start system operation.
