6.78 MHz High Power ZVS Class-D Development Board
Created: Feb 09, 2016
No description available.
Due to the problem that comes with hard switching method, manufacturers try to minimize the overlap to in turn minimize the switching losses by increasing the rate of change of current (di/dt) and voltage (dv/dt) in the switching waveform. This led to the soft switching or Zero Voltage Switching (ZVS). The ZVS is a conventional PWM power conversion during the MOSFET’s on time but with resonant switching transitions. This reference design is an EPC9065 high efficiency, ZVS differential mode class-D amplifier development board. It operates at, but is not limited to 6.78 MHz, which is the lowest ISM band. This board aims to simplify the evaluation process of a high power ZVS class-D amplifier.
This evaluation board is comprised of a differential mode ZVS Class-D amplifier, a 6.78MHz oscillator, and a separate heat sink for each class-D section. Since this evaluation board is not limited to 6.78MHz, frequencies can be varied. Placing a jumper into J60 can disable the oscillator. It can also be externally shutdown by using an externally controlled open collector/drain transistor on the terminals of J60. The oscillator disable switch needs to be capable of sinking at least 25mA. The external oscillator can then be connected to J71. The amplifier board features the EPC2007C and the EPC8010, which are 100V rated enhancement-mode gallium nitride FETs (eGaN FET). The EPC2007C is used in the class-D amplifier while the EPC8010 is used as a synchronous bootstrap FET. The amplifier can be set to operate in either differential mode or single ended mode and includes the gate drivers and 6.78MHz oscillator.
This reference design is useful in applications that require class-D amplifiers. These applications range from low-power portable applications in which battery life, board-space requirements, and EMI compliance are important, to high-power applications where minimizing heat sinking requirements and heat generation is vital. This ZVS Class-D amplifier is used in applications such as A4WP wireless power using eGaN FETs by including all the critical components on a single board that can be easily connected into an existing system.