Datasheet EPC23111 (Efficient Power Conversion) - 9

eGaN® IC DATASHEET
EPC23111
Figure 9: Parallel Thermal Resistance Paths of EPC23111 IC
temperature of 22°C, with a 48 VDC supply and natural convection, the
from Junction to Ambient
EPC91131 can deliver 11 ARMS per phase without a heatsink and 15 ARMS per phase with a heatsink attached, with a temperature rise below 60°C TIM: Soft Thermal Pad = Heat path Heatsink r-Global P/N: TB-X 500 µm from the IC case to ambient. Motor drive operating points at PWM = 200-300 µm compressed 20, 50, and 100 kHz, embedded deadtime = 25 ns, with and without thickness heatsink at 22°C ambient temperature, under natural convection.
Figure 10: EPC91131 Evaluation Board (see EPC91131 Quick Start Guide for details)
RθJC (top) = 0.61 °C/W RθJC (bottom) = 3.7 °C/W To achieve even lower effective thermal resistance, another path is provided from junction to the relatively lower thermal resistance Si substrate of the GaN IC structure to the exposed backside of the entire die at the top of the package to achieve a RθJC_top of 0.4 °C/W. This lower PCB thermal resistance path facilitates attachment of a topside heatsink through thermal interface material (TIM) to the exposed backside of the die. Note that the backside of the die is connected to the PGND (=AGND) pins which potential y provides added benefits of using electrical y conductive TIM which has >2X higher thermal conductivity and lower cost than the insulating type. Typical parameters of electrical y
Figure 11: EPC91131 eGaN IC Temperature Increase vs.
conducting vs. insulating TIMs are shown in the table below. The
Ambient Temperature
resistance between the exposed backside and PGND is at least 100 Ω,
EPC23111 @ 22°C Ambient Temperature
due to the low doping level of the Si substrate. 70 Solid line is without heatsink 60
)
Dashed line is with heatsink
Typical parameters of electrically conducting vs. insulating TIMs e (°C
50
tur Type of TIM Thermal Conductivity Relative
40
(W/m · K) Cost
30
Electrically Conducting
40 1
empera Electrically Insulating
15 1.3 20
Delta T 20 kHz 50 kHz
10
100 kHz
Another factor in specifying the output current rating is electromigration 0 from a metal urgical standpoint. For EPC23111 this limit is a function of 0 2 4 6 8 10 12 14 16 18
RMS Phase Current (A
the metal ization structure underlying the two output FETs plus their
RMS )
connection to the lead-frame and the three exposed power bars.
Power Supplies – VIN , VDRV , VDD , and VBOOT Motor Drive Inverter Application
The EPC23111 IC only requires an external 5 V VDRV power supply. Internal low-side and high-side power supplies, VDD and VBOOT, are The EPC91131 evaluation board shown in Figure 10 is a 3-phase BLDC generated from the external supply via two independent switches. motor drive inverter board that can deliver up to 11 ARMS steady- Figure 12 shows the simplified circuit diagram of the different power state output current and up to 20 ARMS pulsed output current (tpulse= supplies inside the IC and their interaction with each other. 300 ms at 5%, 10%, and 20% of the total period). The EPC91131 contains all the necessary critical function circuits to support a complete motor drive inverter. Figure 11 depicts the steady-state thermal performance of the EPC91131 board. When operated on a motor bench at an ambient EPC – POWER CONVERSION TECHNOLOGY LEADER | EPC-CO.COM | ©2026 | For more information: info@epc-co.com | 9