SLUSBC8C December   2013  – July 2018


  1. Features
  2. Applications
  3. Description
    1.     Wireless Power Consortium (WPC or Qi) Inductive Power System
  4. Revision History
  5. Device Comparison Table
  6. Pin Configuration and Functions
    1.     Pin Functions
  7. Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Typical Characteristics
  8. Detailed Description
    1. 8.1 Overview
      1. 8.1.1 A Brief Description of the Wireless System
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  Details of a Qi Wireless Power System and bq51003 Power Transfer Flow Diagrams
      2. 8.3.2  Dynamic Rectifier Control
      3. 8.3.3  Dynamic Efficiency Scaling
      4. 8.3.4  RILIM Calculations
      5. 8.3.5  Input Overvoltage
      6. 8.3.6  Adapter Enable Functionality and EN1/EN2 Control
      7. 8.3.7  End Power Transfer Packet (WPC Header 0x02)
      8. 8.3.8  Status Outputs
      9. 8.3.9  WPC Communication Scheme
      10. 8.3.10 Communication Modulator
      11. 8.3.11 Adaptive Communication Limit
      12. 8.3.12 Synchronous Rectification
      13. 8.3.13 Temperature Sense Resistor Network (TS)
      14. 8.3.14 3-State Driver Recommendations for the TS-CTRL Pin
      15. 8.3.15 Thermal Protection
      16. 8.3.16 WPC v1.2 Compliance – Foreign Object Detection
    4. 8.4 Device Functional Modes
  9. Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 bq51003 Wireless Power Receiver Used as a Power Supply
        1. Design Requirements
        2. Detailed Design Procedure
          1. Using the bq51003 as a Wireless Power Supply
          2. Series and Parallel Resonant Capacitor Selection
          3. COMM, CLAMP, and BOOT Capacitors
          4. Control Pins and CHG
          5. Current Limit and FOD
          6. RECT and OUT Capacitance
        3. Application Curves
      2. 9.2.2 Dual Power Path: Wireless Power and DC Input
        1. Design Requirements
        2. Detailed Design Procedure
        3. Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Development Support
    2. 12.2 Receiving Notification of Documentation Updates
    3. 12.3 Community Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

Using the bq51003 as a Wireless Power Supply

Figure 32 is the schematic of a system which uses the bq51003 as a power supply.

When the system shown in Figure 32 is placed on the charging pad, the receiver coil is inductively coupled to the magnetic flux generated by the coil in the charging pad which consequently induces a voltage in the receiver coil. The internal synchronous rectifier feeds this voltage to the RECT pin which has the filter capacitor C3.

The bq51003 identifies and authenticates itself to the primary using the COMM pins by switching on and off the COMM FETs and hence switching in and out CCOMM. If the authentication is successful, the transmitter will remain powered on. The bq51003 measures the voltage at the RECT pin, calculates the difference between the actual voltage and the desired voltage VRECT-REG, (threshold 1 at no load) and sends back error packets to the primary. This process goes on until the input voltage settles at VRECT-REG. During a load transient, the dynamic rectifier algorithm will set the targets specified by VRECT-REG thresholds 1, 2, 3, and 4. This algorithm is termed Dynamic Rectifier Control and is used to enhance the transient response of the power supply.

During power up, the LDO is held off until the VRECT-REG threshold 1 converges. The voltage control loop ensures that the output voltage is maintained at VOUT-REG to power the system. The bq51003 meanwhile continues to monitor the input voltage, and maintains sending error packets to the primary every 250 ms. If a large overshoot occurs, the feedback to the primary speeds up to every 32 ms to converge on an operating point in less time.