In the world of smart wearables and portable gadgets, one-cell or two-cell battery systems are ubiquitous.
As modern applications demand ever-higher accuracy in fuel gauging, relying on a bare ADC to estimate remaining capacity can lead to wildly inaccurate readings under certain conditions—undermining user experience.
Increasingly, top-tier devices incorporate a dedicated analog front-end (AFE) fuel gauge chip that not only provides precise coulomb counting but also implements secure, authenticated battery accessory detection.
Geehy’s BMP561 is their latest AFE solution tailored for these needs.
Key Highlights
Small Packaging
Supports DFN, CSP and QFN packages to fit the tight volume constraints of battery packs.
WLCSP12: 1.75 × 2.15 mm
DFN12: 2.70 × 4.20 mm
QFN16: 3.25 × 3.25 mm (Biggest package with 9 GPIOs)
High-Precision ADCs
• One 16-bit voltage ADC (V-ADC)
• One 16-bit current ADC (C-ADC)
Both converters ensure accurate tracking of charge and discharge currents.
Integrated MCU Functions
• Cortex-M0+ core running at up to 4 MHz peripheral clock
• Watchdog timer and reset management
• On-chip temperature sensor
• 32-bit Flash memory
• UART, I2C and high-speed communication interfaces
Robust Security
• HMAC-SHA256 engine: 256 pclk cycles per auth (≈64 μs @ 4 MHz)
• 512-bit input SHA256 mode for arbitrary-length hashing: 64 pclk cycles per hash (≈16 μs @ 4 MHz)
These features enable secure battery authentication and data integrity protection.
Ultra-Low Power
• Multiple low-power modes for minimal standby current
• Flash memory supports low-power sleep
• V-ADC can wake the system only when a measurement is needed, maximizing battery lifespan
Why Choose BMP561?
Precision Meets Security
By combining high-resolution ADCs with hardware-accelerated SHA256/HMAC, BMP561 ensures both accurate fuel gauging and trusted battery authentication.
Compact and Flexible
With DFN/CSP options and multiple GPIOs, it integrates easily into space-constrained battery packs and supports custom accessory interfaces.
Comprehensive Software Ecosystem
Geehy provides complete example code covering UART, I2C, timers, V-ADC/C-ADC, HMAC and in-application programming (IAP). A full toolchain—including encryption utilities, flash programmers and a PC-based battery monitor—speeds up evaluation and development.
Advanced Charging Algorithms: Boosting Battery Safety and Performance
With the rapid development of smart devices and the increasing demands on battery life, advanced charging algorithms have become critical for optimal battery management. Modern systems now adapt charging currents and voltages according to temperature, battery voltage, and charge state, achieving both safety and efficiency.
Let’s explore the major advantages of such charging algorithms:
JEITA-Compliant Charging: Enhancing Temperature Safety
By dynamically adjusting charging voltage and current based on temperature and battery voltage—the foundation of the JEITA standard—batteries are protected from overheating or overcooling.
This standardization not only prevents thermal runaway but also ensures reliable charging across different environmental conditions, thereby extending battery lifespan.
Lifespan Optimization: SOH and Cycle Count Based Management
Fast Charging: Meeting the Need for Speed
Smart Voltage Compensation: Real-Time System Adjustment
Pre-Charge and Trickle Charge: Gentle Battery Awakening
For deeply depleted batteries, a safe pre-charge phase followed by trickle charging brings the battery up to a healthy voltage level before full charging begins. This reduces stress on the cells, improves safety, and prevents damage to aged or over-discharged batteries.
Charge Voltage Gradient Descent: Precise Full Charge
By gradually lowering the charging voltage at the final stage, the battery is brought to a full charge in a controlled and stable manner. This approach avoids overcharging and maximizes usable battery capacity.
Charge Pausing and Inhibition: Intelligent Safety Checks
Whether you’re designing the next generation of smartwatches, fitness trackers or portable medical devices, the BMP561 delivers the precision, security and low-power performance required for cutting-edge battery management.
Please contact the Geehy team for design support and evaluation boards.
