The **WCT-121-R/E** is a wireless charging transmitter module based on the Qi standard (Version 1.2.x). It is designed to deliver power wirelessly to compatible devices like smartphones and IoT hardware. --- ## 1. Core Technical Specifications The module is characterized by its high-efficiency power transfer and integrated control logic. | Feature | Specification | |:---|:---| | **Input Voltage** | DC 5V / 9V (Supports QC 2.0/3.0) | | **Output Power** | 5W / 7.5W / 10W / 15W (Auto-negotiation) | | **Standard** | WPC Qi V1.2.4 | | **Conversion Efficiency** | Up to 80% | | **Sensing Distance** | 3mm - 8mm | | **Protection Features** | OTP, OCP, OVP, FOD | --- ## 2. Key Electronic Components The architecture of the WCT-121-R/E consists of several critical subsystems: ### A. Integrated Controller (The Brain) Usually powered by an MCU (Microcontroller Unit) or a dedicated Wireless Power Controller chip. * **Function:** Manages the communication between the transmitter and the receiver using Backscatter Modulation. It adjusts the PWM (Pulse Width Modulation) frequency to match the power demand. ### B. Power Stage (Inverter) * **MOSFETs:** A Full-Bridge or Half-Bridge inverter circuit. * **Function:** Converts the DC input into a high-frequency AC signal (usually between 110kHz and 205kHz) to drive the induction coil. ### C. Resonant Tank (Coil & Capacitors) * **Induction Coil:** A high-Q copper Litz wire coil. * **Resonant Capacitors:** High-voltage C0G/NP0 ceramic capacitors. * **Function:** Creates an electromagnetic field to transfer energy via magnetic induction. ### D. Foreign Object Detection (FOD) * **Sensors:** Utilizes current and voltage sensing resistors. * **Function:** Detects if metal objects (keys, coins) are placed between the charger and the phone. It prevents overheating by shutting down the power if an anomaly is detected. --- ## 3. Communication Logic Unlike simple power supplies, this module involves a digital handshake: 1. **Ping Phase:** The module sends a brief signal to check for a device. 2. **Identification & Configuration:** The receiver sends its ID and power requirements. 3. **Power Transfer:** The module adjusts current flow based on feedback packets from the phone. --- ## 4. Pinout Interface (Typical) Most WCT-121 variants utilize a simple interface for integration: ```markdown 1. VIN (+) : 5V-12V DC Input 2. GND (-) : Ground 3. LED-R : Status Indicator (Red) 4. LED-B : Status Indicator (Blue) 5. BUZ : Optional Buzzer Output ```