NiMH Battery Pack Charge Controller

The DS2715 is well suited for cost-sensitive charger applications where the battery pack is either internal or external to the application. It has been optimized for safe and reliable charging of 1 to 10 NiMH cells in series. The internal gain block can be selected as either a comparator or transconductance amplifier for charge current regulation. This makes the DS2715 configurable as a switched DC charger, a linear current regulator, or a switch-mode current source. The DS2715 pre-conditions severely depleted cells before entering full charge mode. It terminates full charge using the dT/dt technique, which requires an external sensing thermistor. Over-temperature, under-temperature, and over-voltage detection prevents charging under unsafe conditions. A user selectable charge timer allows charge rates from 0.167C to 2C. FAST-CHARGE, TOPOFF and DONE modes are included for highly reliable, safe charging of NiMH cells. Discharge mode allows the DS2715 to enter a low power sleep state while the cell pack is being discharged.

Applications

* Handheld Gaming * Handheld POS Terminals * Portable DVD Players * Portable Television Sets * Test Equipment

* Charges 1 to 10 NiMH Cells

* FAST-CHARGE up to a 2C Rate

* PRECHARGE and TOPOFF Charge Modes Help Cell Conditioning

* Load Detection Allows the DS2715 to Enter Low Power Sleep Mode (Less than 10µA) while the Cell Pack is Discharged

* dT/dt Charge Termination Eliminates Cell Charge Stress

* Monitors Voltage, Temperature, and Time for Safety and Secondary Termination

* Regulates Current through Either Linear Control or Switch-Mode Control

* LED Output Displays Charge State

* Small 16-Pin SO Package