The **BQ28Z560-R1** is a highly integrated, single-cell Li-Ion or Li-Polymer battery gas gauge and protection solution. It utilizes Texas Instruments’ proprietary **Impedance Track™** technology to provide highly accurate state-of-charge (SoC) data. --- ### 1. Core Functions and Features The device serves three primary roles in an electronic system: | Feature | Description | | :--- | :--- | | **Gas Gauging** | Uses Impedance Track technology to calculate remaining capacity with high precision by modeling battery impedance. | | **Protection** | Integrated safety hardware monitors for overvoltage, undervoltage, overcurrent, and short-circuit conditions. | | **Authentication** | Includes SHA-1/HMAC authentication to ensure only authorized battery packs are used with the device. | --- ### 2. Key Electronic Components & Internal Blocks To understand how the BQ28Z560-R1 functions within a circuit, it is essential to look at its internal architecture: #### A. Analog Front End (AFE) * **Voltage Sensing:** High-precision ADCs measure the cell voltage to determine the charge state and trigger safety limits. * **Current Sensing:** It measures the voltage drop across an external **Sense Resistor** (typically 5mΩ to 20mΩ) to track coulombs flowing in and out. * **Temperature Sensing:** Supports an external NTC thermistor to monitor battery heat during rapid charging or discharging. #### B. The Processor & Memory * **Fuel Gauge Engine:** A low-power RISC processor runs the Impedance Track algorithms. * **Non-Volatile Memory:** Stores battery chemistry profiles (ChemID), cycle counts, and lifetime data. #### C. Communication Interface * **I2C / HDQ:** It communicates with the host system (like a smartphone processor or a laptop MCU) using standard protocols to report % of battery remaining, time-to-empty, and health status. --- ### 3. External Component Requirements A typical application circuit for the BQ28Z560-R1 requires several critical external parts: 1. **Sense Resistor ($R_{SENSE}$):** A low-resistance, high-precision resistor used for current measurement. 2. **Protection MOSFETs:** N-Channel FETs are used to disconnect the battery in case of a fault (Charge/Discharge protection). 3. **Thermistor:** A 10kΩ NTC resistor for thermal safety monitoring. 4. **Decoupling Capacitors:** Small ceramic capacitors (0.1µF) to filter noise on the supply pins ($V_{CC}$). --- ### 4. Technical Specifications Summary | Parameter | Value / Range | | :--- | :--- | | **Cell Count** | 1-Cell (1S) | | **Communication** | I2C, HDQ | | **Package** | 12-pin SON (2.5 mm × 4.0 mm) | | **Voltage Accuracy** | ±10 mV | | **Current Accuracy** | ±1% | --- ### 5. Benefits of Impedance Track™ Unlike traditional "Coulomb Counting" (which drifts over time) or "Voltage Lookup" (which is inaccurate under load), **Impedance Track** measures the internal resistance of the battery in real-time. This allows the BQ28Z560-R1 to maintain 99% accuracy even as the battery ages.