IEEE Power Electronics Magazine - September 2019 - 36

EPC, Navitas, and Power Integrations
adjust system performance through
have taken the integrated route, while
software upgrades by using the comGaN drivers must
suppliers such as GaN Systems, Infipany's intelligent configuration tool
provide precise
neon, and Transphorm still prefer
(ICT) and a device programmer. No
the discrete method for driving
soldering is required. The ICT offers
voltages with sufficient
GaN transistors.
the configuration of different drive
drive capability to
TI has been supplying stand-alone
parameters, including on/off gate voltgate
drivers for low-voltage GaN
ages, a dc link and temperature fault
achieve fast turn-on
FETs for low-side and half-bridge
levels, and augmented switching proand turn-off speeds,
configuration, such as the LMG1020
files. Small changes to the augmented
and LMG1205. Later, combining 80-V
switching profiles can yield dramatic
with protection
eGaN FETs with a driver in a sinimprovements in switching efficiency,
and reliability.
gle package, TI created the 80-V,
overshoot, ringing, and short circuit
10 -A GaN half-bridge power stage
protection, according to the proddesignated LMG5200. Now, it has
uct's datasheet.
developed a family of GaN devices that integrate 600-V GaN
Although high-voltage SiC junction FETs (JFETs) offer
FETs with high-speed drivers and built-in protection in one
many parametric advantages for improving efficiency and
compact quad-flat no-leads package that is optimized to
density in many power conversion applications, they are
minimize parasitics and provide a high-performance result
difficult to implement due to nonstandard voltages and a
[3]. According to TI, integration allows designers to build
lack of an intrinsic diode when switching inductive loads.
smaller, more efficient solutions with high system reliability
UnitedSiC has overcome these challenges by developing a
for applications ranging from fewer than 100 W to 10 kW. A
cascode configuration. By combining its depletion-mode
good example is the recently introduced LMG341x family.
SiC JFET with a conventional low-voltage silicon MOSFET
These GaN parts can be easily assessed with evaluation
as a cascode pair in a single standard package, the commodules, such as the LMG3410EVM-018, LMG3410-HB-EVM,
pany has crafted SiC-based normally off cascode FETs that
and LMG3411EVM-029. In addition, the company has gencan be easily driven with standard silicon gate drives. As a
erated a reference design to help users quickly underresult, according to UnitedSiC, the SiC cascodes offer a true
stand the components' use in overall system applications.
drop-in replacement to silicon IGBTs, silicon MOSFETs,
Although TI is evaluating the monolithic integration of GaN
including SiC MOSFETs.
FETs with drivers and protection circuits on a single die,
there is no word on when such devices will be released.
Driving GaN FETs
However, EPC, Navitas, and Power Integrations are
Like SiC MOSFETs, gate drivers play an important role in
seriously committed to monolithic integration of GaN
squeezing maximum performance out of WBG devices.
FETs, drivers, and logic circuits. In fact, EPC is in the proBesides operating at high frequencies, GaN drivers must
cess of releasing a monolithic version of its LMG5200, with
provide precise voltages with sufficient drive capability to
more functions on-chip. EPC CEO Alex Lidow believes
achieve fast turn-on and turn-off speeds, with protection
that the greatest opportunity for GaN to impact the perand reliability. In the GaN arena, suppliers including TI,
formance of power conversion systems will come from the
intrinsic ability to integrate power-level and signal-level
devices on the same chip. Toward that goal, EPC unveiled
VDD
VDDF
VIN
an integrated solution that combined two 150-V, 5-A eGaN
Synchronized
FETs with two gate drivers, offering low propagation delay
Boot
and up to 7-MHz operation from a 5-V supply. Now, the company has gone many steps further to integrate two power
HSIN
Level
Output
transistors, level-shifters, synchronous bootstrapping, and
Shift
Driver
driver circuitry into a monolithic IC that can be controlled
SW
Logic
with standard low-power logic gate levels and operate effiPlus
VDD
ciently at switching frequencies of up to 7 MHz (Figure 5).
UVLO
The DrGaN ICs, labeled EPC2151 and EPC2152, are planned
LSIN
Output
to be introduced in late 2019.
Driver
While the EPC2151 is an 80-V, 10-A integrated DrGaN
GND
GND
half-bridge power stage using two asymmetrical eGaN FETs
in a chip-scale package measuring 3.9 mm by 2.6 mm by
0.9 mm, the EPC2152 is a symmetrical version. Both of these
FIG 5 EPC's monolithic half-bridge power stage with integrated
GaN power ICs are capable of interfacing to digital controlinput logic interface, level shifting, bootstrap charging, gate
lers that use standard CMOS or transistor-transistor logic
driver buffer circuits, and eGaN FETs.

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