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NiCd/NiMH Battery Fast-Charge Controllers

Charges 1-16 Series Cells at Rates Up to 4C

Product Details

The MAX712/MAX713 fast-charge Nickel Metal Hydride (NiMH) and Nickel Cadmium (NiCd) batteries from a DC source at least 1.5V higher than the maximum battery voltage. 1 to 16 series cells can be charged at rates up to 4C. A voltage-slope detecting analog-to-digital converter, timer, and temperature window comparator determine charge completion. The MAX712/MAX713 are powered by the DC source via an on-board +5V shunt regulator. They draw a maximum of 5µA from the battery when not charging. A low-side current-sense resistor allows the battery charge current to be regulated while still supplying power to the battery's load.

The MAX712 terminates fast charge by detecting zero voltage slope, while the MAX713 uses a negative voltage-slope detection scheme. Both parts come in 16-pin DIP and SO packages. An external power PNP transistor, blocking diode, three resistors, and three capacitors are the only required external components.

The evaluation kit is available: Order the MAX712EVKIT-DIP for quick evaluations of the linear charger.

Key Features

  • Fast-Charge NiMH or NiCd Batteries
  • Voltage Slope, Temperature, and Timer Fast-Charge Cutoff
  • Charge 1 to 16 Series Cells
  • Supply Battery's Load While Charging (Linear Mode)
  • Fast Charge from C/4 to 4C Rate
  • C/16 Trickle-Charge Rate
  • Automatically Switch from Fast to Trickle Charge
  • Linear Mode Power Control
  • 5µA (max) Drain on Battery when Not Charging
  • 5V Shunt Regulator Powers External Logic

Applications/Uses

  • Cellular Phones
  • Cordless Phones
  • Handy-Terminals
  • Laptop, Notebook, and Palmtop Computers
  • Portable Stereos

Simplified Block Diagram

MAX712, MAX713: Typical Operating Circuit MAX712, MAX713: Typical Operating Circuit Zoom icon

Technical Docs

Design & Development

Click any title below to view the detail page where available.

Description

The MAX713SWEVKIT-SO is a fully assembled and tested surface-mount board. The MAX713 high-current, switch-mode battery charger controls a P-channel power MOSFET, allowing charge currents up to 1A. Switch-mode operation typically provides 75%-efficient conversion, reducing heat compared to linear-regulator solutions.

The MAX713SWEVKIT can also be used to evaluate the MAX712 just by replacing the MAX713CSE with a MAX712CSE.

View Details

Features

  • Up to 1A Charge Current
  • 45V Peak Input Voltage Range
  • Switch-Mode Operation Reduces Heat Dissipation
  • Surface-Mount Components
  • Charges 1 to 16 Series Cells

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Support & Training

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Parameters

Key Features

  • Fast-Charge NiMH or NiCd Batteries
  • Voltage Slope, Temperature, and Timer Fast-Charge Cutoff
  • Charge 1 to 16 Series Cells
  • Supply Battery's Load While Charging (Linear Mode)
  • Fast Charge from C/4 to 4C Rate
  • C/16 Trickle-Charge Rate
  • Automatically Switch from Fast to Trickle Charge
  • Linear Mode Power Control
  • 5µA (max) Drain on Battery when Not Charging
  • 5V Shunt Regulator Powers External Logic

Applications/Uses

  • Cellular Phones
  • Cordless Phones
  • Handy-Terminals
  • Laptop, Notebook, and Palmtop Computers
  • Portable Stereos

Description

The MAX712/MAX713 fast-charge Nickel Metal Hydride (NiMH) and Nickel Cadmium (NiCd) batteries from a DC source at least 1.5V higher than the maximum battery voltage. 1 to 16 series cells can be charged at rates up to 4C. A voltage-slope detecting analog-to-digital converter, timer, and temperature window comparator determine charge completion. The MAX712/MAX713 are powered by the DC source via an on-board +5V shunt regulator. They draw a maximum of 5µA from the battery when not charging. A low-side current-sense resistor allows the battery charge current to be regulated while still supplying power to the battery's load.

The MAX712 terminates fast charge by detecting zero voltage slope, while the MAX713 uses a negative voltage-slope detection scheme. Both parts come in 16-pin DIP and SO packages. An external power PNP transistor, blocking diode, three resistors, and three capacitors are the only required external components.

The evaluation kit is available: Order the MAX712EVKIT-DIP for quick evaluations of the linear charger.

Simplified Block Diagram

MAX712, MAX713: Typical Operating Circuit MAX712, MAX713: Typical Operating Circuit Zoom icon

Technical Docs

Support & Training

Search our knowledge base for answers to your technical questions.

Filtered Search

Our dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal