1 Features
1• Robust 5-W Solution With 50% Lower Losses for
Improved Thermals
– Inductorless Receiver for Lowest Height Profile
Solution
– Adjustable Output Voltage (4.5 to 8 V) for Coil
and Thermal Optimization
– Fully Synchronous Rectifier With 96%
Efficiency
– 97% Efficient Post Regulator
– 79% System Efficiency at 5 W primary•
WPC v1.1 and PMA Compliant Communication
• Patented Transmitter Pad Detect Function
Improves User Experience
• I2C Communication with Host

2 Applications
• Smart Phones, Tablets, and Headsets
• Wi-Fi Hotspots
• Power Banks
• Other Handheld Devices

3 Description
The bq51221 device is a fully contained wireless
power receiver capable of operating in both the WPC
and PMA protocols which allows a wireless power
system to work with both WPC and PMA inductive
charging standards. The bq51221 device provides a
single device power conversion (rectification and
regulation) as well as the digital control and
communication for both standards. It also has
autonomous detection of protocol and requires no additional active devices. The bq51221 device
complies with the WPC v1.1 and PMA communication
protocol. Together with the WPC or a PMA primary•
side controller, the bq51221 device enables a complete wireless power transfer system for a
wireless power supply solution. The receiver allows
for synchronous rectification, regulation and control
and communication to all exist in a market-leading
form factor, efficiency, and solution size.