Battery pack fuel-gauge IC includes SHA-256 security to prevent cloning
The devices are ultra-low power stand-alone fuel gauge ICs that implement the Maxim ModelGauge m5 algorithm without requiring host interaction for configuration. This feature suits the MAX1720x/MAX1721x as “pack-side” fuel gauges. The MAX17201/MAX17211 monitor a single cell pack. The MAX17205/MAX17215 monitor and balance a 2S or 3S pack or monitor a multiple-series cell pack.
To prevent battery pack cloning, the ICs integrate SHA-256 authentication with a 160-bit secret key. Each IC incorporates a unique 64-bit ID. Use the parts, Maxim suggests, in digital still and video cameras; e-readers; handheld computers and terminals; handheld radios; portable game players; portable medical equipment; and smartphones and tablets.
The ModelGauge m5 algorithm combines the short-term accuracy and linearity of a coulomb counter with the long-term stability of a voltage-based fuel gauge, along with temperature compensation to provide industry-leading fuel gauge accuracy. The IC automatically compensates for cell ageing, temperature, and discharge rate, and provides accurate state of charge (SOC) in milliampere-hours (mAh) or percentage (%) over a wide range of operating conditions. As the battery approaches the critical region near empty, the ModelGauge m5 algorithm invokes a special error correction mechanism that eliminates any error. The ICs provide accurate estimation of time-to-empty and time-to-full, Cycle+ age forecast, and three methods for reporting the age of the battery: reduction in capacity, increase in battery resistance, and cycle odometer.
The ICs provide precision measurements of current, voltage, and temperature. Temperature of the battery pack is measured using an internal temperature measurement and up to two external thermistors supported by ratiometric measurements on auxiliary inputs. A Maxim 1-Wire (MAX17211/MAX17215) or 2-wire I²C (MAX17201/MAX17205) interface provides access to data and control registers. The ICs are available in lead-free, 3 x 3 mm, 14-pin TDFN packages.
Maxim Integrated; www.maximintegrated.com/en/products/power/battery-management/MAX17201.html
next page; feature listing…
Features include;
ModelGauge m5 Algorithm
Eliminates error when approaching empty voltage
Eliminates Coulomb-counter drift
Current, temperature, and age compensated
Does not require empty, full, or idle States
No characterisation required for EZ Performance (See the ModelGauge m5 EZ Performance Section)
Cycle+ Age Forecasting observes lifespan
Nonvolatile memory for stand-alone operation
Learned parameters and history logging
Up to 75 words available for user Data
Precision measurement system
No calibration required
Time-to-empty and time-to-full estimation
Temperature measurement
Die temperature
Up to two external thermistors
Multiple series cell pack operation
Low quiescent current
MAX172x1: 18µA active, 9µA hibernate
MAX172x5: 25µA active, 12µA hibernate
Alert indicator for voltage, SOC, temperature, current, and 1% SOC change
High-speed overcurrent comparators
Predicts remaining capacity under theoretical load
SHA-256 authentication
Maxim 1-wire or 2-wire (I²C) interface
SBS 1.1 compatible register Set
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