THINKANTECH & Renesas Webinar Recap: A Deep Dive into the RA6T2-Based 3kW CLLC DC/DC Solution
THINKANTECH & Renesas Webinar Recap: A Deep Dive into the RA6T2-Based 3kW CLLC DC/DC Solution
Introduction
As modern power systems demand ever-increasing levels of sophistication and efficiency, digital power has emerged as a foundational technology, delivering high stability, precise control, and superior conversion efficiency across numerous markets. Renesas Electronics, a long-standing leader in the industrial and power sectors, offers a diverse portfolio of embedded products architected for digital power applications.
THINKANTECH specializes in the research, development, and sales of advanced power semiconductor devices and modules, including Si-MOSFETs & IGBTs, GaN HEMTs, SiC MOSFETs & SBDs, and SiC Modules. Our products are widely deployed in critical energy conversion applications such as consumer electronics, photovoltaics, energy storage, automotive, AI servers, and industrial automation.
In this collaborative initiative, Renesas and THINKANTECH have introduced a cutting-edge 3kW CLLC DC/DC reference design featuring the Renesas RA6T2 MCU and THINKANTECH GaN HEMTs. This solution is engineered to significantly accelerate customer project development cycles.
Webinar Highlights
System Architecture Overview
Live Demonstration of the Solution Hardware
In-Depth Analysis of the Power Stage Design
Featured THINKANTECH Power Devices
Isolation, Signal Chain, and Gate Drive Implementation
GaN Gate Driving Strategies
The MCU Core: A Closer Look at the Renesas RA6T2
Software Algorithms and Control Logic
2-Pole, 2-Zero (2P2Z) Digital Loop Compensation
Key Features of the Renesas RA6T2 MCU:
High-Speed On-Chip Flash
Trigonometric Function Unit (TFU) for Hardware Acceleration
Advanced General PWM Timers (GPT)
High-Speed Analog-to-Digital Converter (ADC)
Event Link Controller (ELC) for Peripheral-to-Peripheral Linking
Selected Q&A Session
Q1: Does the TOLT package require thermal interface material (TIM) and an external heatsink?
A: Yes, both a suitable TIM (like thermal grease) and an external heatsink are necessary for effective thermal management. The mounting method for interfacing a TOLT-packaged device with a heatsink is analogous to that of a standard TO-247 package.
Q2: How can we mitigate EMI/EMC issues related to the switching frequency?
A: EMC performance is not solely correlated with the switching frequency itself but is more dependent on the spectral characteristics of the voltage and current slew rates (dv/dt and di/dt). To mitigate EMC, we recommend selecting an operating frequency that avoids critical EMC test bands. For instance, using a 135 kHz frequency can help stay clear of the 150 kHz conducted emissions band. Furthermore, implementing frequency dithering (spread-spectrum clocking) is highly effective, a feature where digital power control offers a distinct advantage.
Q3: Does the digital power supply include overload protection? What is its response time, and can the user adjust the overload threshold?
A: Yes, comprehensive overload protection is included. The response time is in the millisecond (ms) range. The protection threshold is fully configurable and can be adjusted by the user to meet specific application requirements.
Q4: What is the output PWM waveform error? How robust is its anti-interference capability at high frequencies?
A: From the MCU's perspective, the four high-resolution GPT channels can achieve a timing resolution as fine as 156 ps, a figure verified by our internal testing. However, in a complete system, the effective resolution and noise immunity are influenced by the entire signal chain and electromagnetic environment, including gate drivers and layout parasitics. Therefore, the final anti-interference capability must be evaluated within the context of the specific system design.
Q5: How much does the hardware-accelerated 2P2Z filter improve computation time and reduce CPU load?
A: The actual execution time and CPU resource savings depend on the filter model and the data throughput. For reference, our internal benchmarks on notch and second-order low-pass filters demonstrate significant performance gains.
Q6: What is the achievable sampling rate (MSPS) when using multiple ADC channels simultaneously? Does it support DMA for data acquisition?
A: For multi-channel acquisition, you can strategically allocate sampling tasks across the two independent ADC units to enable simultaneous sampling. For a single unit, the total time per conversion can be calculated as: AD Conversion Time = Trigger Latency + Sampling Time + Conversion Time. Please refer to section 36.9 of the RA6T2 datasheet for detailed timing calculations. Yes, DMA is fully supported for efficient data collection.
Q7: Is the trigonometric function calculation based on a proprietary hardware optimization, or does it use a standard C library?
A: The Renesas RA6T2 includes a dedicated Trigonometric Function Unit (TFU) that provides hardware acceleration for four operations: sin(θ), cos(θ), arctan(y/x), and sqrt(x²+y²). Other trigonometric functions can be implemented efficiently using standard math libraries.
Q8: How is the output voltage soft-start implemented? What are the key considerations?
A: This solution employs a closed-loop soft-start. The digital controller incrementally ramps the output voltage setpoint from 0V to the final target value, ensuring a smooth and controlled voltage rise.
Q9: How should the PCB be designed to handle such high currents? What trace width is required?
A: The output stage of this 3kW solution is designed to handle up to 250A. For currents of this magnitude, standard PCB traces are insufficient. We utilize custom copper bus bars for the high-current output paths to ensure low resistance and effective thermal management.
Q10: How low can the standby power consumption be, and are there special considerations for standby mode?
A: The standby power consumption for this reference design is approximately 5-8W. Achieving this requires careful design of the auxiliary power supply and leveraging the MCU's low-power modes.
About THINKANTECH
THINKANTECH is a cutting-edge wide-bandgap power device company founded by a distinguished team of experts in power semiconductors, marketing professionals from the power supply industry, and a dynamic group of young, entrepreneurial experts.
Recognized for our rapid growth and commitment to quality, we were designated an "Enterprise Above Designated Size" in 2022. In 2023, we achieved the prestigious status of a "National Sci-tech Small and Medium-sized Enterprise" and a "National High-Tech Enterprise," alongside securing our ISO 9001 certification for quality management. Further demonstrating our dedication to excellence, we successfully obtained the IATF 16949 automotive-grade quality management system certification in 2024.
