In‐depth analysis of an RCD snubber applied to a DC‐DC boost converter

This paper introduces a new single switch DC-DC fourth-order boost converter. The proposed converter is the improved version of an existing converter known as the super-boost converter. The improved super-boost ISP converter achieves a smaller input current ripple than the super-boost converter when the same parameters in passive components are used. Conversely, smaller components can be used to achieve the same input current ripple, which leads to a compact and cheaper design. A comparative evaluation showed a reduction of 37.3% of stored energy in inductors to comply with a required input current ripple in comparison with the super-boost converter for a particular design. Experimental results are provided to corroborate this benefit of the ISB proposed topology.

The Fourth-Order Single-Switch Improved Super-Boost Converter with Reduced Input Current Ripple

This article presents local shielding techniques applied to a half-bridge inverter leg with the aim to reduce the common-mode (CM) current noise at converter’s dc input. The research study is conducted for 650-V enhancement mode Gallium Nitride power transistor switches. Main contributors of parasitic capacitances referred to the inverter-leg middle point node are identified. Then, shielding solutions are proposed to reduce the CM current emission by these capacitances. Respecting the precautions concerning the isolation of CM currents of the half-bridge inverter leg, the electromagnetic compatibility measurement setup is developed. Experimental step-by-step addition of local shielding copper layers to different contributors of middle point capacitance shows progressive attenuation of CM noise spectra.

EMI Mitigation of GaN Power Inverter Leg by Local Shielding Techniques

This paper presents local shielding techniques applied to a half-bridge inverter leg with the aim to reduce the common mode (CM) current noise at converter's DC input. The research study is conducted for 650V Enhancement mode Gallium Nitride (GaN) power transistor switches. Main contributors of parasitic capacitances referred to the inverter-leg middle point node are identified. Then, shielding solutions are proposed to reduce CM current emission by these capacitances. Respecting the precautions concerning the isolation of CM currents of the half-bridge inverter leg, the electromagnetic compatibility measurement setup is developed. Experimental step-by-step addition of local shielding copper layers to different contributors of middle point capacitance shows progressive attenuation of CM noise spectra. 

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EMI mitigation of GaN power inverter leg by local shielding techniques

The general wideband modeling method of the power converter is presented on the example of DC-DC buck converter with GaN High Electron Mobility Transistors (HEMT). The models of all basic and parasitic components are briefly described. The two methods of Printed Circuit Board (PCB) layout parameter extraction are presented. The results of simulation in Saber@Sketch simulation software and measurements are compared. Next, the model of the converter is reduced to obtain one lumped inductance of the input filter PCB for the analytical prediction of transistor turn-off ringing frequency and overvoltage. The practical use of the model is presented for sizing optimal capacitance of snubber.

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Wideband Modeling of DC-DC Buck Converter with GaN Transistors

A dc–dc buck converter using gallium nitride (GaN) high electron mobility transistors (HEMTs) is experimentally investigated at the discontinuous-current-mode (DCM) and the triangular-current-mode (TCM) operations. The objective of this article is to specify the power conversion efficiency and attenuation of common-mode (CM) and differential-mode (DM) noise voltage, measured at the line impedance stabilization network (LISN) for the compared control strategies. Zero-voltage switching achieved for the TCM operation improves efficiency with reference to the DCM operation. However, significant attenuation of electromagnetic interference (EMI) spectra is obtained for TCM operation with capacitive snubber. Sizing of capacitor snubber dependent on parasitic inductances of the commutation circuit and rapid switching of GaN HEMTs are illustrated.

EMI Attenuation in a DC–DC Buck Converter Using GaN HEMT

This paper presents the adaptation of a 3D integration concept previously used with vertical devices to lateral GaN devices. This 3D integration allows to reduce loop inductance, to ensure more symmetrical design with especially limited Common Mode emission, thanks to a low middle point stray capacitance. This reduction has been achieved by both working on the power layout and including a specific shield between the devices and the heatsink. The performances of this 3D layout have been verified in comparison with a more conventional 2D implementation, using both simulations and measurements.

3D PCB package for GaN inverter leg with low EMC feature

The improvement of the gate driver for GaN transistor is presented in this paper. The proposed topology contains the overcurrent protectionwith the two-stage turning off and independent control of turn on and off time of the GaN transistor. The operation of driver and its application in thehalf-bridge converter are described using both simulation and prototype measurements. The overcurrent protection was tested in Double Pulse Test(DPT) conditions.

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Pawel B. Derkacz

Papers

EMI Attenuation in a DC–DC Buck Converter Using GaN HEMT

3D PCB package for GaN inverter leg with low EMC feature

EMI Mitigation of GaN Power Inverter Leg by Local Shielding Techniques

Wideband Modeling of DC-DC Buck Converter with GaN Transistors

Gate driver with overcurrent protection circuit for GaN transistors