The Flexible 6-Channel Power Sequencer Reference Design, centered around the microcontroller and discrete DC/DC regulators, provides a powerful, scalable, and reliable solution for managing modern industrial automation systems’ complex power sequencing needs.
Modern industrial automation systems increasingly rely on sophisticated programmable logic controllers (PLCs) equipped with advanced FPGAs (Field Programmable Gate Arrays) or SoCs (System on Chips) to meet the demands of mid- to high-end applications. These complex systems require precise power sequencing for their multiple power supply rails to ensure reliable operation and minimize the risk of failure. To achieve this, a flexible power sequencing solution based on a general-purpose microcontroller paired with discrete DC/DC regulators offers a scalable and user-friendly approach for a wide range of FPGA and SoC applications.
The heart of this power sequencing solution EU096-PWRSEQPOCZ by Renesas is the RL78/G12 microcontroller housed in a compact 32-pin package. This microcontroller not only controls the sequencing process but also offers additional features that enhance system reliability and flexibility. For instance, it includes an integrated ADC (Analog-to-Digital Converter) for monitoring the main input voltage, ensuring that any fluctuations in power supply are quickly detected and managed. Additionally, the microcontroller reads Power Good signals from each DC/DC converter, providing real-time feedback on the health of the power rails.
Given the complexity and critical nature of the components involved, the power sequencing requirements for such applications are stringent. Therefore, a robust solution that ensures seamless power-up and power-down sequences is essential. This solution leverages discrete DC/DC regulators integrated with power MOSFETs and a low-Iq LDO (Low Dropout Regulator) to provide a stable supply voltage to the microcontroller. This configuration supports a wide input voltage range, from 4.5VDC to 24VDC, making it versatile for various industrial environments. A notable feature of this design is its redundancy in monitoring. The microcontroller’s ADC is supplemented by a secondary monitoring system using a 10-bit ADC integrated within the NCU (Network Control Unit), further safeguarding against power rail variations. This dual-monitoring approach significantly reduces the risk of unnoticed power issues that could lead to system failures.
The reference design also includes the RAA211250, a DC/DC synchronous step-down buck regulator, which enhances efficiency by offering programmable PWM (Pulse Width Modulation) switching frequency and internal loop compensation, reducing the overall component count and bill of materials. The flexibility of this design allows users to program power-on and power-off delays through an intuitive GUI, making it adaptable to a wide range of applications. It combines ease of use with robust performance, making it ideal for applications involving FPGAs, SoCs, and other high-performance components.
Renesas has tested this reference design. It comes with a design guide, schematics, assembly drawing, printed circuit board (PCB) layout, and more. The company’s website has additional data about the reference design. To read more about this reference design, click here.
