Simplifying Power IC Designs: 3 Companies Tackle Power Conversion Systems

July 02, 2021 by Antonio Anzaldua Jr.

Simplifying designs are never easy, especially with power. So how did these three companies tackle simplifying power conversion systems?

Design simplification is never easy, even if you're attempting to free up the smallest, most minute amount of space. This challenge is especially true when it comes to power. 

Power conversion systems (PCS) often incorporate redundancy and voltage regulation, which in turn requires more components and thus more difficulties in layout design.


An example of a PCS using SiC MOSFETS.

An example of a PCS using SiC MOSFETS. Image used courtesy of Infineon


This power and component requirement can be especially true for industrial applications, motors, and pumps, where power efficiency and low dissipation are essential. 

Despite the challenges to design simplification, it is constantly strived for. Recently, three companies have announced new products that claim to simplify power conversion systems and improve the system's overall efficiency and reliability.  

The first company's product this article will dive into is an AC/DC converter from ROHM.

ROHM Adds a SiC MOSFET to AC/DC Converter

In industrial settings, the auxiliary power supply's role changes since it must deliver different DC voltage levels for gate drivers and control units. 

Power designers often struggle with obtaining high-efficiency systems and experience high losses when conventional silicon (Si) MOSFET devices are used. One industry-standard solution is found by adding a heatsink and additional discrete components to improve efficiency and possibly decrease power losses.

ROHM Semiconductor, a leading developer in power ICs, is known for creating devices that often improve the performance of silicon carbide (SiC) power semiconductors. Recently, ROHM claims to have launched its industry-first AC/DC converter integrated circuit (IC) with a built-in 1700 V SiC MOSFET.

This design includes ROHM's converter, the BM2SC12xFP2-LBZ, explicitly designed for auxiliary power supplies in industrial applications; this includes commercial streetlights and commercial air-conditioning systems inverters, and AC servo drives.


This converter was tested in a 400 VAC, 48 W output auxiliary power supply, enabled automatic board mounting, reducing the need for external parts.

This converter was tested in a 400 VAC, 48 W output auxiliary power supply, enabled automatic board mounting, reducing the need for external parts. Image used courtesy of ROHM


ROHM's converter is quasi-resonant (QR) based, allowing the circuit to cut power losses while increasing product reliability by minimizing component failure. Overall power efficiency can then be increased by 5%, with reliability and energy savings increasing as well. 

Adding to this release, ROHM also offers a design reference evaluation board that can be coupled with this converter, which the board can then deliver up to 48 W at 400 VAC without the need for a heatsink. 

By avoiding a standard solution such as a Si MOSFET coupled with a Si drive control IC, the power conversion efficiency can then go from 78.5% to 83.5%. 

Another potential benefit ROHM claims that this new converter achieves lower noise than conventional PWM systems, directly affecting the equipment downstream. Aside from removing the need for external parts, this converter offers various levels of protection: soft start function, burst operation function, over current limiter per cycle, over-voltage protection, and overload protection.

Though ROHM's design simplification attempts to simplify and create a better component, ON Semiconductor is also making strides with its power factor correction modules. 


ON Semiconductor’s Power Factor Correction Modules

In power electronics, the power factor should be as close to one as possible because this indicates the efficiency of the dissipated energy. However, that would be an "ideal" situation, in which, most of the time, the power factor ratio comes up under one, requiring additional components to correct it. 

Power factor correction (PFC) refers to improving the power factor by deliberately implementing reactance to mitigate the effects of other inductance, which is where you can find large capacitor banks. Their purpose is to balance out the effects of inductors in the system to correct the power factor. 

Recently, including FPC, ON Semiconductor announced its new integrated converter-inverter-PFC modules for industrial motor drives, servo drives, and HVAC fans and pumps. 


A schematic diagram for the NXH50M65L4C2ESG. Image used courtesy of ON Semiconductor


The NXH50M65L4C2SG and NXH50M65L4C2ESG are transfer-molded power integrated modules (TMPIM) based upon standard aluminum oxide (AI203) substrate and enhanced low thermal resistance substrate. These converter-inverter-PFC modules are rated at 650 V for 50 A that can convert through single-phase and invert 3-phase systems. 

These modules are designed for robust systems and equipped with an embedded thermistor that monitors device temperature during operation. Either module converter can be coupled with ON’s latest NCD57252, Isolated Dual-Channel IGBT/MOSFET Gate Driver. By doing so, the designer could potentially lower heat dissipation, increase reliability, and become cost-effective to standard industrial driving motors.

The final product that this article will look at is a new step-down regulator from STMicroelectronics. 


STMicroelectronics’ Synchronous Step-down Regulators 

To finish rounding up the different companies working to simplify power design, STMicroelectronics recently launched its integrated 1.5 A synchronous regulators. 

STMicroelectronics' L6981, synchronous step-down regulators, are an extension of an existing line of high-efficiency converters. This new family member claims it will simplify power supplies by integrating power elements, feedback circuitry, and on-chip safety features. 

ST states that these regulators are rated to deliver up to 1.5 A to the load with 90% typical efficiency at full load. The designer can also add converters that are optimized for light-load efficiency and noise performance.


A block diagram for the L6981.

A block diagram for the L6981. Image used courtesy of STMicroelectronics


The two variants of these regulators have an input voltage from 3.5 V to 38 V, which can make them suited in various industrial equipment. A key feature is how the output voltage is adjustable from 0.85 V up to the input voltage value using external resistors.

This new member to ST's family of regulators could be helpful for designers looking to have more flexibility in their power design.


Simplifying the Simplifications

In the end, for designers to simplify power IC designs, the design specifications need to be followed; however, new solutions can often make things a lot easier.  

For instance, by utilizing ROHM's AC/DC converter, designers can remove external parts and increase efficiency. By implementing ON Semiconductor's PFC solution, designers have the potential to diminish inductance and unwanted noise in large systems. And lastly, STMicroelectronics aims to give designers flexibility with improved power consumption during single-phase conversion onto 3-phase inversions. 



Have you ever simplified a power conversion system? How did you accomplish it? Share your experiences in the comments down below.