## Overview of the P9221-R The **P9221-R** is a highly integrated, magnetic induction, wireless power receiver (Rx) developed by Renesas (formerly IDT). It is designed to meet the WPC (Wireless Power Consortium) **Qi 1.2.2 specification** for medium power applications, capable of delivering up to **15W** of power. --- ### Key Technical Specifications | Parameter | Specification | | :--- | :--- | | **Standard** | WPC Qi 1.2.2 (Medium Power) | | **Output Power** | Up to 15W | | **Output Voltage** | Adjustable (typically 5V to 12V) | | **Interface** | I2C (Serial Interface) | | **Efficiency** | Up to 87% (System level) | | **Package** | 52-WLCSP (Wafer Level Chip Scale Package) | --- ### Major Internal Components The P9221-R integrates several critical electronic sub-systems into a single chip to minimize PCB footprint: 1. **Full-Bridge Synchronous Rectifier:** * Converts the AC current induced in the receiver coil into a stable DC voltage. * Uses high-efficiency MOSFETs to minimize thermal loss. 2. **LDO Regulator:** * Provides a regulated output voltage to the load. * Programmable output levels via I2C or external resistors. 3. **32-bit ARM® Cortex®-M0 Processor:** * The "brain" of the chip that manages the Qi communication protocol. * Handles foreign object detection (FOD) and thermal management. 4. **Analog-to-Digital Converter (ADC):** * Monitors input/output voltage, current, and die temperature for safety and feedback. 5. **Communication Modulator:** * Sends packets back to the transmitter (Tx) by modulating the load (ASK modulation) to request more or less power. --- ### External Components Required To build a functional wireless charging circuit with the P9221-R, the following external parts are necessary: * **Rx Coil:** An induction coil (e.g., 10µH to 15µH) that captures the magnetic field. * **Resonant Capacitors ($C_{S}$ and $C_{P}$):** High-quality COG/NP0 ceramic capacitors used to tune the LC circuit to the correct resonant frequency. * **Thermistor (NTC):** Connected to the TS pin to monitor battery or coil temperature. * **I2C Pull-up Resistors:** Necessary for communication with a host microcontroller (MCU). --- ### Application Diagram (Simplified) ```mermaid graph LR A[Rx Coil] --> B[Resonant Caps] B --> C[P9221-R IC] C --> D[Output Voltage VOUT] C <--> E[Host MCU via I2C] F[NTC Sensor] --> C ``` --- ### Key Features * **FOD (Foreign Object Detection):** Prevents heating of metal objects placed between the Tx and Rx. * **Over-Voltage/Over-Current Protection:** Ensures the safety of the powered device. * **Low Standby Power:** Optimized for battery-operated devices like smartphones and tablets.