DS2784 stand-alone, single-cell battery fuel gauge IC typical working circuit

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One-piece inductor

Overview:

The DS2784 operates from a 2.5V to 4.6V supply and can be integrated into a single-cell Li-Ion (Li+) or Li+ polymer battery pack. The remaining capacity is given in mAh and percentage. Built-in Li+ protection and SHA-1-based challenge-response authentication ensure safe operation.

The device estimates capacitance by precisely measuring voltage, temperature, and current, along with battery characteristics and application parameters. The available capacity register gives a conservative estimate of the amount of electricity at the current temperature and discharge rate.

In addition to non-volatile (NV) memory for battery compensation and application parameters, the device also provides 16-byte EEPROM memory dedicated to preserving host system and/or battery pack manufacturer information. This simplifies battery batch and date tracking, or NV save for system or battery usage status.

The 1-Wire® interface provides 16kbps or 143kbps serial communication for accessing data registers, control registers, and user memory. In addition, in the hash-based information authentication code (HMAC) authentication protocol, 1-Wire communication can use SHA-1 as the challenge-response packet authentication of the hash algorithm.

Key features:

• Precision voltage, temperature and current measurement systems
• Estimating residual capacity by coulomb counter, discharge rate, temperature, and battery characteristics
• Estimating battery aging characteristics during learning
• Low cost detection resistor
• Calibrable gain and temperature coefficient
• Li+ safety circuit - overvoltage, undervoltage, overcurrent, short circuit protection
• Programmable overvoltage and overcurrent safety threshold
• Authentication using SHA-1 algorithm and 64-bit key
• 32-byte parameter EEPROM
• 16-byte user EEPROM
• Dallas 1-Wire bus with 64-bit unique ID
• Tiny, lead-free, 14-pin TDFN package for easy integration in prismatic battery packs

Application / Use:

• Cordless VoIP phone
• Digital camera and camera
• Portable GPS navigation
• Smartphone/PDA

Typical working circuit: