SLUSBC8C December   2013  – July 2018

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Wireless Power Consortium (WPC or Qi) Inductive Power System
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
    1.     Pin Functions
  7. 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. 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. 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. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
          1. 9.2.1.2.1 Using the bq51003 as a Wireless Power Supply
          2. 9.2.1.2.2 Series and Parallel Resonant Capacitor Selection
          3. 9.2.1.2.3 COMM, CLAMP, and BOOT Capacitors
          4. 9.2.1.2.4 Control Pins and CHG
          5. 9.2.1.2.5 Current Limit and FOD
          6. 9.2.1.2.6 RECT and OUT Capacitance
        3. 9.2.1.3 Application Curves
      2. 9.2.2 Dual Power Path: Wireless Power and DC Input
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
        3. 9.2.2.3 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

8.3.3 Dynamic Efficiency Scaling

The Dynamic Efficiency Scaling feature allows for the loss characteristics of the bq51003 to be scaled based on the maximum expected output power in the end application. This effectively optimizes the efficiency for each application. This feature is achieved by scaling the loss of the internal LDO based on a percentage of the maximum output current. Note that the maximum output current is set by the KIMAX term and the RILIM resistance (where RILIM = KIMAX / IMAX). The flow diagram show in Figure 19 illustrates how the rectifier is dynamically controlled (Dynamic Rectifier Control) based on a fixed percentage of the IMAX setting. Table 2 summarizes how the rectifier behavior is dynamically adjusted based on two different RILIM settings.

Table 2. Dynamic Efficiency Scaling

OUTPUT CURRENT PERCENTAGE RILIM = 1116 Ω
IMAX = 250 mA		 RILIM = 488 Ω
IMAX = 500 mA		 VRECT
0 to 10% 0 A to 0.025 A 0 A to 0.05 A 7.08 V
10 to 20% 0.025 A to 0.050 A 0.050 A to 0.100 A 6.28 V
20 to 40% 0.050 A to 0.100 A 0.100 A to 0.200 A 5.53 V
>40% > 0.100 A > 0.200 A 5.11 V

Figure 5 illustrates the shift in the Dynamic Rectifier Control behavior based on the two different RILIM settings. With the rectifier voltage (VRECT) being the input to the internal LDO, this adjustment in the Dynamic Rectifier Control thresholds will dynamically adjust the power dissipation across the LDO where:

Equation 1. bq51003 eq1_Pdis.gif

Figure 3 illustrates how the system efficiency is improved due to the Dynamic Efficiency Scaling feature. Note that this feature balances efficiency with optimal system transient response.