Features

• Complete Fast Charger Controller for Single, 2-, 3- or 4-Series Cell NiMH/NiCd Batteries
• No Firmware or Microcontroller Required
• Termination by –∆V, Maximum Voltage or Maximum Time
• No Sense Resistor or Blocking Diode Required
• Automatic Recharge Keeps Batteries Charged
• Programmable Fast Charge Current: 0.4A to 2A
• Accurate Charge Current: ±5% at 2A
• Fast Charge Current Programmable Beyond 2A with External Sense Resistor
• Automatic Detection of Battery
• Precharge for Heavily Discharged Batteries
• Optional Temperature Qualified Charging
• Charge and AC Present Status Outputs Can Drive LED
• Automatic Sleep Mode with Input Supply Removal
• Negligible Battery Drain in Sleep Mode: <1µA
• Manual Shutdown
• Input Supply Range: 4.5V to 10V
• Available in 16-Lead DFN and TSSOP Packages

Typical Application

Description

The LTC4060 is a complete fast charging system for NiMH or NiCd batteries. Just a few external components are needed to design a standalone linear charging system.

An external PNP transistor provides charge current that is user programmable with a resistor. A small external capacitor sets the maximum charge time. No external current sense resistor is needed, and no blocking diode is required.

The IC automatically senses the DC input supply and battery insertion or removal. Heavily discharged batteries are initially charged at a C/5 rate before a fast charge is applied. Fast charge is terminated using the –∆V detection method. Backup termination consists of a programmable timer and battery overvoltage detector. An optional external NTC thermistor can be used for temperature-based qualification of charging. An optional programmable recharge feature automatically recharges batteries after discharge.

Manual shutdown is accomplished with the SHDN pin, while removing input power automatically puts the LTC4060 into sleep mode. During shutdown or sleep mode, battery drain is <1µA.

The LTC4060 is available in both low profile (0.75mm) 16- pin 5mm × 3mm DFN and 16-lead TSSOP packages. Both feature exposed metal die mount pads for optimum thermal performance.