DS2438

Smart Battery Monitor


Description

The DS2438 smart battery monitor provides several functions that are desirable to carry in a battery pack: a means of tagging a battery pack with a unique serial number, a direct-to-digital temperature sensor which eliminates the need for thermistors in the battery pack, an A/D converter which measures the battery voltage and current, an integrated current accumulator which keeps a running total of all current going into and out of the battery, an elapsed time meter, and 40 bytes of nonvolatile EEPROM memory for storage of important parameters such as battery chemistry, battery capacity, charging methodology and assembly date. Information is sent to/from the DS2438 over a 1-Wire® interface, so that only one wire (and ground) needs to be connected from a central microprocessor to a DS2438. This means that battery packs need only have three output connectors: battery power, ground, and the 1-Wire interface.

Because each DS2438 contains a unique silicon serial number, multiple DS2438s can exist on the same 1-Wire bus. This allows multiple battery packs to be charged or used in the system simultaneously.

Applications for the smart battery monitor include portable computers, portable/cellular telephones, and handheld instrumentation battery packs in which it is critical to monitor real-time battery performance. Used in conjunction with a microcontroller in the host system, the DS2438 provides a complete smart battery pack solution that is fully chemistry-independent. The customization for a particular battery chemistry and capacity is realized in the code programmed into the microcontroller and DS2438 EEPROM, and only a software revision is necessary should a designer wish to change battery pack chemistry.
DS2438: Block Diagram DS2438: Block Diagram Enlarge+

Key Features

  • Unique 1-Wire interface requires only one port pin for communication
  • Provides unique 64-bit serial number to battery packs
  • Eliminates thermistors by sensing battery temperature on-chip
  • On-board A/D converter allows monitoring of battery voltage for end-of-charge and end-of-discharge determination
  • On-board integrated current accumulator facilitates fuel gauging
  • Elapsed time meter in binary format
  • 40-byte nonvolatile user memory available for storage of battery-specific data
  • Operating range -40°C to +85°C

Applications/Uses

  • Cell Phones
  • Digital Still Cameras
  • Digital Video Cameras
  • Palmtops, Handy Terminals (incl. barcode)
  • Pen Entry Palmtops, PDAs and Organizers
  • Smart Battery Packs/Chargers
Part Number Functions Battery Type Interface User Data Storage
(Bytes)
Parameters Measured VSUPPLY
(V)
VSUPPLY
(V)
Features Oper. Temp.
(°C)
Budgetary
Price
min max See Notes
DS2438 
Fuel Gauge
Status Monitor
1-2 Cell Li-Ion
2-6 Cell NiMH
1-Wire 40 EEPROM
Current
Temperature
Time
Voltage
2.4 10
AFE
Digital Current Accumulation
Unique ID
-40 to +85 $2.60 @1k
See All Battery Monitors, Protectors, and Selectors (34)
Pricing Notes:
This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific and version-specific prices and delivery, please see the price and availability page or contact an authorized distributor.


DS2438EVKIT: Smart Battery Monitor Evaluation Kit

Tools & Models

Software
DS2438K Evaluation Kit Software

 

Related Resources


MAX14676, MAX14676A
Wearable Charge Management Solution

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  • Easy-to-Implement Li+ Battery Charging
  • Minimize Power-Management Footprint though High Integration

MAX14676, MAX14676A
Wearable Charge Management Solution

  • Extend System Use Time Between Battery Charging
  • Easy-to-Implement Li+ Battery Charging
  • Minimize Power-Management Footprint though High Integration