When wireless charging power reaches 25W, heat becomes an unavoidable issue. It must be fast while staying cool—this places higher demands on PCB layout, chip selection, and thermal structure. Bieland has launched a 25W magnetic wireless charging module. It supports adding a fan + thermoelectric cooler (TEC), providing an active cooling option for high-power scenarios. Let’s take a look at how this solution is designed and implemented.

1. Module Overview: Compact Layout, Built for Cooling

The PCB measures 60×57mm, a compact design. The most striking feature is the cutout in the center of the board—a mounting slot specifically reserved for the thermoelectric cooler. The TEC can be embedded into it and attached directly to the back of the coil, actively drawing away heat generated during charging, and can work with a fan to form a complete airflow cooling system. The module supports magnetic attachment, with a ring of magnets around the coil, making it perfectly compatible with iPhone MagSafe and future Qi2 Android devices.

2. Core Components: Controller + Full Bridge, One-Chip Triple-Output

1) Controller IC: Bieland D9812

Located in the lower left corner of the PCB, it is the Bieland D9812 one-chip, triple-output wireless charging controller IC.

The key specifications of the D9812 are as follows:

① Broad Power and Standard Support

The D9812 is compatible with the latest WPC Qi2.2 specification and supports MPP (Magnetic Power Profile) and EPP (Extended Power Profile) protocols. It covers a very complete range of power levels: 5W/7.5W/10W/15W (EPP and MPP)/25W (MPP). This means a single chip is fully compatible with everything from legacy Qi devices and current mainstream 15W Android flagship phones to the latest iPhone’s 25W magnetic fast charging.

② Powerful Processing Core

Core frequency 72MHz, PWM frequency up to 200MHz. The high core frequency ensures real-time communication and decoding capability, while the 200MHz PWM frequency makes power transfer more precise and smooth, helping reduce electromagnetic interference (EMI) and improve efficiency.

③ Unique Hybrid Demodulation Technology

The D9812 uses a combination of digital demodulation and analog demodulation. Compared with pure digital demodulation solutions, this greatly improves communication anti-interference capability and decoding success rate in MPP mode. This advantage is especially pronounced in environments with coil coupling misalignment or noise.

④ Integrated Type-C Controller and Fast-Charging Protocols

The chip integrates a Type-C controller and supports PD3.0/2.0 and QC2.0 protocols. This means the module can directly handshake with PD or QC adapters to request 5V/9V/12V/15V input voltages, eliminating the need for an additional protocol IC and simplifying the BOM.

⑤ Comprehensive Protection Mechanisms

Cycle-by-cycle hardware-level OCP: cycle-by-cycle overcurrent protection detects current anomalies in each switching cycle. Its response speed is far faster than software protection, effectively preventing coil short circuits or overload damage.

FOD (Foreign Object Detection): by continuously monitoring power transfer efficiency and Q-factor detection, it identifies metal foreign objects and prevents hazards caused by eddy-current heating.

UVLO, OVP, OTP: undervoltage, overvoltage, and overtemperature protection are all included.

⑥ One Chip, Triple Output, Flexible Expansion

The D9812 is essentially a three-channel wireless charging transmitter controller that can simultaneously control three independent wireless charging devices. In other reference designs, the D9812 can simultaneously drive two 25W MPP coils plus one 5W earbud coil, fully demonstrating the architectural advantage of “one chip, triple output.”

⑦ Ease of Debugging and Mass Production

The chip supports USB in-system firmware upgrades, eliminating the need for a dedicated programmer. After the product ships, if it needs to support new phones or optimize algorithms, updates can be completed via the USB port, reducing maintenance costs.

2. Full-Bridge IC: Bieland D9015A

Located in the upper right corner of the PCB, near the coil connection. The D9015A drives the coil to generate an alternating magnetic field and works with the D9812 to complete the full wireless charging transmitter solution.

In addition, the upper part of the board has a USB-C port, LED indicator, and a 4.7μH alloy inductor. The inductor is used for power conversion, with low loss and low temperature rise.

Close-up of the external NTC (thermistor) interface.

Close-up of the indicator after power-on: it lights up and then turns off.

Close-up of the NPO resonant capacitor. This capacitor has high temperature stability, ensuring the resonant frequency does not drift.

3. Thermal Design: Reserved Active Cooling Capability

This is a structural highlight of the module: a cutout in the center of the PCB provides a mounting slot for the thermoelectric cooler. With a TEC and fan installed, the temperature of the coil and PCB can be further reduced, making it suitable for temperature-sensitive scenarios such as gaming charging stands and long-duration high-power output. Below are the module’s temperature rise test data:

Without a thermoelectric cooler and fan installed, during continuous 25W output, the maximum temperature is only 65°C. This is far lower than many similar solutions (typically 70–80°C). This benefits from the D9812’s high-efficiency design and optimized PCB layout. If a thermoelectric cooler and fan are added, the temperature can be further reduced—this is also the purpose of the module’s cutout design, giving customers who need extreme cooling an option.

4. Power-On Test: Compatible with Apple MagSafe

Power-on test: connect a PD power source; the blue indicator lights up and then turns off (standby mode).

Place it on the test fixture; the test results are shown below:

Place a MagSafe-compatible iPhone on it; the charging animation pops up on the phone, indicating that it has successfully entered MPP 25W mode.

5. Summary: A High-Power Wireless Charging Module with Flexible Cooling

This Bieland 25W wireless charging module completes an integrated design of controller + full bridge + reserved cooling slot within a small 60×57mm footprint.

For wireless charging products pursuing high power and low heat—whether desktop magnetic stands, gaming charging docks, or in-car wireless chargers—this module provides a reference design with flexible cooling options.

If you are interested in the chip solution, welcome to contact us for samples.