With switching frequency as high as 500kHz, The LT1510CS8 current mode PWM battery charger is the smallest, simplest, most efficient solution to fast-charge modern rechargeable batteries including lithium-ion (Li-Ion), nickel-metal-hydride (NiMH) and nickel-cadmium (NiCd) that require constant-current and/or constant-voltage charging. The internal switch is capable of delivering 1.5A DC current (2A peak current). The 0.1Ω onboard current sense resistor makes the charging current programming very simple. One resistor (or a programming current from a DAC) is required to set the full charging current (1.5A) to within 5% accuracy. The LT1510CS8 with 0.5% reference voltage accuracy meets the critical constant-voltage charging requirement for lithium cells.
The LT1510CS8 can charge batteries ranging from 2V to 20V. Ground sensing of current is not required and the battery’s negative terminal can be tied directly to ground. A saturating switch running at 200kHz (500kHz for LT1510-5) gives high charging efficiency and small inductor size. A blocking diode is not required between the chip and the battery because the chip goes into sleep mode and drains only 3µA when the wall adaptor is unplugged. Soft start and shutdown features are also provided. The LT1510CS8 is available in a 16-pin fused lead power SO package with a thermal resistance of 50°C/W, an 8-pin SO and a 16-pin PDIP.
Feature
- Charges NiCd, NiMH and Lithium-Ion Batteries - Only One 1/10W Resistor Is Needed to Program Charging Current
- High Efficiency Current Mode PWM with 1.5A Internal Switch and Sense Resistor
- 3% Typical Charging Current Accuracy
- Precision 0.5% Voltage Reference for Voltage Mode Charging or Overvoltage Protection
- Current Sensing Can Be at Either Terminal of the Battery
- Low Reverse Battery Drain Current: 3µA
- Charging Current Soft Start
- Shutdown Control
- 500kHz Version Uses Small Inductor
Applications
- Chargers for NiCd, NiMH and Lithium Batteries
- Step-Down Switching Regulator with Precision Adjustable Current Limit
