5MHz PWM-controlled current-mode resonant DC-DC converter using GaN-FETs

In this paper, the method of the realization of a MHz level switching frequency DC-DC converter for high power-density is presented. For high power-density, Gallium Nitride field effect transistor (GaN-FET) and current-mode resonant DC-DC converter are adopted. In addition, the proposed pulse width modulation (PWM) control method which is suitable for the isolated current-mode resonant DC-DC converter operated at MHz level switching frequency, and the novel primary-side zero voltage switching (ZVS) turn on method for the proposed PWM control are presented. Some experiments have been done with 5MHz isolated DC-DC converter which has GaN-FET, and the total volume of the circuit is 16.14cm3. With the proposed PWM control method, input voltage range is 36-44V, and maximum load current range is 8A at Vi = 44V. The primary-side ZVS turn on is confirmed, and the maximum power-efficiency is 89.4%.7th International Power Electronics Conference, IPEC-Hiroshima - ECCE Asia 2014; Hiroshima; Japan; 18 May 2014 through 21 May 201

High frequency PWM-controlled current-mode resonant DC-DC converter with boost conversion

In this paper, a new pulse width modulation (PWM) control method for the isolated current-mode resonant converter with a fixed switching frequency is presented. The circuit topology is the same as a conventional resonant converter with synchronous rectification and without any additional components. The control technique for the output voltage regulation is proposed with the unique PWM control for synchronously-rectifying switches. By using the transformer\u27s leakage inductance and the PWM control, the boost conversion can be realized. Also, the zero-voltage switching (ZVS) operation can be done for primary switches, simultaneously. Some experiments have been done with 5MHz isolated DC-DC converter which has Gallium Nitride field effect transistor (GaN-FET).2013 15th European Conference on Power Electronics and Applications, EPE 2013; Lille; France; 2 September 2013 through 6 September 201

Five-Megahertz PWM-Controlled Current-Mode Resonant DC?DC Step-Down Converter Using GaN-HEMTs

High power efficiency and high power density are required in regulated isolated dc-dc converters. In this paper, a novel pulsewidth modulation (PWM) control method that is suitable for an isolated current-mode resonant dc-dc converter operated at a megahertz-level switching frequency is proposed. The output voltage with the proposed method can be regulated with no additional components at a fixed switching frequency. In addition, the zero-voltage switching (ZVS) of primary-side switches at turn on can be maintained. The principle of the proposed method and the method of the ZVS operation in the proposed method are explained. Some experiments have been performed with a 5-MHz isolated step-down dc-dc converter using gallium nitride high-electron-mobility transistors; the output voltage is 12 V, and the total volume of the circuit is 16.14 cm3. With the proposed PWM control method, the input voltage range is 42-45.5 V, and the maximum load current range is 10 A at Vi = 45.5 V. The ZVS of the primary-side switches at turn on is confirmed in all experimental regions, and the maximum power efficiency is 89.2%

Considerations of Physical Design and Implementation for 5?MHz-100?W LLC Resonant DC-DC Converters

Recently, high power-density, high power-efficiency, and wide regulation range isolated DC-DC converters have been required. This paper presents considerations of physical design and implementation for wide regulation range MHz-level LLC resonant DC-DC converters. The circuit parameters are designed with 3-5 MHz-level switching frequency. Also, the physical parameters and the size of the planar transformer are optimized by using derived equations and finite element method (FEM) with Maxwell 3D. Some experiments are done with prototype LLC resonant DC-DC converter using gallium nitride high electron mobility transistors (GaN-HEMTs); the input voltage is 42-53 V, the reference output voltage is 12 V, the load current is 8 A, the maximum switching frequency is about 5 MHz, the total volume of the circuit is 4.1 cm3, and the power density of the prototype converter is 24.4 W/cc