#WIRE PROBE CST MICROWAVE STUDIO DRIVERS#
#WIRE PROBE CST MICROWAVE STUDIO DRIVER#
#WIRE PROBE CST MICROWAVE STUDIO FULL#

But it is difficult to quantify the actual circuit behavior when parasitic elements are activated by switch-path di/ dt and dv/ dt. The significant parasitic elements and gate drive current vectors are evident in the nearby figure depicting the of gate/driver distributed impedance and sink/source currents.

Distributed gate/driver impedances and sink/source currents for a half-bridge, gate-drive transmission line.

#WIRE PROBE CST MICROWAVE STUDIO DRIVER#

If the gate driver is underdamped, oscillations at the FET gate and switch node can create excessive electromagnetic interference (EMI) and electrical overstress (EOS). If the gate driver output is overdamped, the GaN advantage will be partially lost. It is affected by dc and ac parasitic impedances including PCB layout copper, component internal inductance, FET capacitances and driver dc resistance. Still, the PCB and component parasitics that were benign with silicon MOSFETS often become problematic when using WBG transistors.Д¬urrent flow from the gate driver of a power FET is complex. At 24 V/nsec, the measured switch node dv/ dt is at least ten times faster than what is typically seen with silicon MOSFETs and yet, GaN technology is capable of even faster dv/ dt. The accompanying figure illustrates the half-bridge switch node behavior of a 48-V-to-1-V buck converter delivering 10 A. What to expect with GaN Switch-node voltage rise time (10-90%) transition to 48 V, 1.7 nsec for this buck converter. These GaN devices typically exhibit a gate oxide capability comparable to that of silicon MOSFETs. Some GaN manufacturers leverage the ultralow on-resistance of GaN technology by building high-voltage enhancement-mode GaN transistors in a cascode arrangement of a low-voltage silicon MOSFET and high-voltage depletion-mode GaN device. This 600-V, 12-A device integrates a gate driver with a depletion-mode (normally on) GaN FET that delivers high-frequency, enhancement-mode switch operation from a logic-level input. To help address this need, TI introduced the LMG3410.

#WIRE PROBE CST MICROWAVE STUDIO DRIVERS#

GaN FETs with a low-voltage gate oxide capability need specialized GaN FET gate drivers like the Texas Instruments LM5113.ДЄs we will see, the key requirement in advancing high-frequency power is to minimize distributed parasitic coupling. In fact, gate-source voltages exceeding about 6 V can damage some GaN transistors.

#WIRE PROBE CST MICROWAVE STUDIO FULL#

It is the ultralow gate charge characteristic of WBG transistors that facilitates high-frequency operation in high-power applications, reducing both power stage and gate driver losses in hard-switch applications.ДЄlso evident from a gate charge curve is that a full saturation of the vertically-structured, super-junction transistor requires nearly twice the gate potential compared with the laterally-structured GaN device. The rate at which this happens is determined by the driver output current and the device gate charge. The gate driver sources and sinks current into the gate terminal to move up and down the deviceвЂ™s gate charge curve. Until the gate-drain вЂњmiller capacitanceвЂќ of the FET is charged, the device remains in a high on-resistance state. As such, the turn-on and turn-off behavior is largely a function the deviceвЂ™s composite gate charge. MOSFETs built-in silicon and the latest WBG transistors are both FETs. Gate charge of a 650-V enhancement mode GaN transistor (green) and a super junction, silicon MOSFET (orange) of comparable R DSON. In this regard, 3D electromagnetic (EM) field solvers help isolate and resolve printed circuit board (PCB) and component parasitic coupling that otherwise would compromise the wide bandgap (WBG) transistor advantage. Today power transistors built on wide-bandgap (WBG) semiconductor materials including silicon carbide (SiC) and gallium nitride (GaN) are being used to realize higher power efficiency and higher power density at a lower cost. More recently, however, these heterojunction transistors have evolved to address a broader scope of high-frequency, high-voltage and high-current power applications. These so-called heterojunction, field effect transistors (FETs) were originally developed for high-frequency RF power amplifiers. HIGH ELECTRON MOBILITY TRANSISTORS (HEMTS) were first introduced in the early 1980s and are touted for their exceptional switching qualities. HereвЂ™s how a 3D EM simulation can be used to accurately gauge gate-driver trace inductance.

Wire probe cst microwave studio