Page 53 - PEN Ebook March 2021

Semiconductors Semiconductors

GaN and copper clip create a technology mix for

650 V high-power FETs when it comes to heat
capacity and thermal conductivity.

From simulations described in figure 4, the engi-
neers have estimated a Rth of just 0.173 °C/W for
CCPAK in comparison with 0.7 °C/W of TO-247.

Whether it is the AC/DC PFC stage, a DC/DC
converter, or traction inverter, the basic building

block for most topologies is a half-bridge. Hence,
when GaN FETs are compared against Si FETs
in a simple boost converter, the GaN technology
shows its superior performance.

Figure 3: Self inductance @ frequency 100 MHz.
Nexperia’s top-side cooled GAN039-650NTB is
THERMAL PERFORMANCE AND a solution used in a half-bridge demonstration Figure 5: Half bridge demo efficiency.
HALF-BRIDGE ADVANTAGES board – 400 VIN and 230 VOUT at 100 kHz with

Thermal management has long been a design 57.4% duty configuration operating at an ambient
challenge for power applications. When designs temperature of 23.1 °C.
had space for large bulky heatsinks it was rel-
atively easy to draw heat away from the circuit In a 400 VDC buck-mode set-up with a low-side
board and semiconductor components. Howev- VDS for ID of 20 A, the spike, overshoot and ring-
er, as power levels and both power and circuit ing are almost negligible during both the turn-on
density have increased, this has become more and turn-off. This provides a t advantage in terms
difficult to handle. of noise and any silicon related Qrr issues, and

efficiency results of 99%.

Figure 6: CCPAK1212 switching waveform.

For More Information

▶ Next generation HV power GaN technology and the benefits of copper-clip SMD
packaging (CCPAK), Dr. Dilder Chowdhury, Talk at Power Electronics Forum

▶ Nexperia

Figure 4: Thermal simulation power GaN FET.

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