Holtek Wireless Charging Solutions: Holtek offers application specific microcontrollers which include all important features for a wireless power transmitter or wireless power receiver design. These are peripherals like a demodulation function and PWM function with adjustable dead time for the transmitter or the rectifier and modulation functions for the receiver.
Holtek also provides Qi certified reference designs. Currently for 5W applications.
Charging battery-powered devices without a wired connection is interesting for many applications. With a focus on charging mobile phones, the Wireless Power Consortium defined the Qi (pronounced “chee”) standard years ago. However, with a power transfer of 5W to 15W, the standard is also suitable for many other portable devices.
The standard ensures that all Qi certified devices are compatible with each other – regardless of manufacturer, standard version, as well as other factors – to guarantee a high level of user-friendliness. In addition, the standard also ensures the safety of devices and users. Safety precautions such as heat shielding or foreign object detection are defined here and must be fulfilled by every certified device.
The standard regulates the physical characteristics of power transmission and communication between power receiver and power transmitter, as well as the system components that the power receiver or power transmitter must include.
Detailed information on the Qi standard can be found on the website of the Wireless Power Consortium.
Holtek currently has two Wireless Charger Transmitter MCUs and one Receiver MCU in their portfolio. HT66FW2230/2250 (TX) and BP66FW1242 (RX) MCUs all support 5W Qi wireless power designs.
The newer HT66FW2350 transmitter MCU is also suitable for 15W designs that run on the Qi side with the Extended Power Profile. Inside this IC the FSK modulation function for bidirectional communication, required by the standard for the transmitter, is integrated. Another advantage is the second demodulation circuit within the MCU. This allows a direct implementation of voltage and current demodulation in parallel.
The HT66W2230 contains only one demodulation circuit. Therefore, the current demodulation, for example, has to be realized via external operational amplifiers.
The BP66FW1242 receiver MCU also features an integrated charging function for lithium-polymer cells, which further simplifies corresponding designs. It provides up to 1A charging current.
The Wireless Charging Transmitter reference design from Holtek is based on the HT66FW2230, making it suitable for 5W designs. The design is Qi certified and offers features such as Foreign Object Detection (FOD), over- and undervoltage detection, overcurrent and overtemperature detection in addition to power control. LEDs are integrated as status indicators as well.
The design documentation is available on Holtek’s dedicated website.
Here you can find the schematic, PCB files and also the firmware. The firmware is available as source code in assembler format as well as a binary file.
This allows the design to be customized. Holtek offers customers support in the certification process to speed it up and shorten the time to market for their products.
Holtek’s new Wireless Charging Receiver reference design is based on the BP66FW1242 MCU and is also rated for 5W. The design was realized in the form factor of a charging case for wireless ear buds. The battery of the charging case can be charged wirelessly or via USB. This design is also Qi certified and includes all relevant functions.
The charging and discharging current is measured via an external resistor and the integrated ADC. This enables monitoring of the battery’s state of charge and thus safe charging or discharging management.
In addition, a software-based Coulomb counter using the ADC and RTC is also implemented, as well as a Bluetooth function based on the Holtek BC7161 Bluetooth MCU. This allows to display the charging status of the charging case via a smartphone app. The status LEDs of the charging case also indicate the battery level.
The smartphone app for reading battery status is available for both iOS and Android.
Do you need more information? Our team will be happy to advise you on Holtek wireless charging solutions. Contact us directly or send us your request in the following web form