## Overview of the P9235A-R The **P9235A-R** is a highly integrated, magnetic induction, wireless power transmitter (TX) IC developed by Renesas (formerly IDT). It is specifically designed for applications requiring up to **5W of power delivery**, compliant with the WPC (Wireless Power Consortium) Qi specification. --- ### Core Specifications The following table summarizes the primary electrical and functional characteristics of the P9235A-R: | Parameter | Specification | | :--- | :--- | | **Input Voltage Range** | 4.25V to 5.5V | | **Output Power** | Up to 5W | | **Qi Compliance** | WPC 1.2.4 (Base Power Profile) | | **Processor** | Integrated 32-bit ARM® Cortex®-M0 | | **Communication** | I2C Interface | | **Package** | 40-VQFPN (5.0 x 5.0 mm) | | **Efficiency** | > 80% (System Level) | --- ### Key Internal Components The P9235A-R is a "System on Chip" (SoC) for wireless charging, meaning it integrates several electronic sub-systems: 1. **Full-Bridge Inverter:** The IC contains low-resistance integrated MOSFETs that form a full-bridge inverter. This stage converts the DC input into an AC signal to drive the external resonant tank (coil and capacitors). 2. **ARM® Cortex®-M0 Microcontroller:** This internal "brain" manages the Qi protocol state machine, handles Foreign Object Detection (FOD), and allows for firmware customization via the I2C interface. 3. **Demodulator & Decoder:** It includes dedicated circuitry to sense the back-scattered data sent by the Receiver (RX) through the power coil. This allows the transmitter to adjust power levels or stop charging based on RX feedback. 4. **Protection Circuitry:** * **Over-Current Protection (OCP)** * **Over-Voltage Protection (OVP)** * **Thermal Shutdown:** Protects the IC if it exceeds safe operating temperatures. 5. **Voltage Regulators:** Internal LDOs (Low Drop-Out regulators) generate the necessary internal voltages for the logic and analog blocks from the 5V input. --- ### Application Circuit Block Diagram To use the P9235A-R, the following external electronic parts are typically required: * **Wireless Charging Coil:** Typically a "Type A11" or similar Qi-standard coil. * **Resonant Capacitors:** High-quality C0G/NP0 ceramic capacitors used to tune the LC tank to the 100-205kHz range. * **I2C Pull-up Resistors:** Necessary if connecting to an external host controller. * **Current Sense Resistor:** Used by the IC to monitor the power being delivered to the coil for FOD calculations. --- ### Example Configuration Snippet (Firmware Context) While much of the logic is hard-coded, parameters like the FOD threshold can be adjusted via I2C registers: ```c // Example: Concept of setting a register over I2C #define P9235A_ADDR 0x61 #define FOD_CONFIG_REG 0x34 void set_fod_threshold(uint8_t value) { i2c_write(P9235A_ADDR, FOD_CONFIG_REG, value); } ```