ONSemi Launches Line of Auxiliary Power Supplies For EVsNovember 30, 2020 by Antonio Anzaldua Jr.
ON Semiconductor (ONSemi) has launched four auxiliary power supply solutions that are able to deliver 800V and 400V to electric vehicles (EVs) and hybrid electric vehicles (HEVs) battery systems.
Systems with isolated supplies for IGBTs and SiC MOSFET drivers are able to gather power at the low-voltage level to drive controls, communications, and safety technologies. In automation, there is generally one large power supply/battery and an onboard charging system that is required to power the high and low voltage sensors, controls, and power modules.
Requirements for auxiliary power supplies are diverse due to the need for low-voltage implementations. Image used courtesy of ON Semiconductor.
Through the many subsystems of a HEV/EV, the power supply has gravitated away from a traditional 12V battery supply to 48V-800V high-voltage battery bus. Making it critical for power supplies to be versatile and flexible in handling low and high voltage inputs.
ON Semiconductor’s High-Voltage Power Supplies
ONSemi has four new products, two of which are designed for regulating power on the primary-side, with an input voltage range from 250V to 900V, making it ideal for EVs and HEV battery systems. ONSemi’s SECO−HVDCDC1362−15W15V−GEVB is a SiC auxiliary power supply that outputs 15W continuously over a stable 15V output. The SECO−HVDCDC1362−40W15V−GEVB, the second high-voltage solution from ONSemi, is also a SiC auxiliary power supply but is able to provide 40W continuously over a stable 15V output.
Block diagram for high-voltage auxiliary power supply, provides engineers with design flexibility by only needing a single layer of PCB with no external components required. Image used courtesy of ON Semiconductor.
Both high-voltage auxiliary power supplies feature a flyback transformer that provides 4kV isolation to power low voltage components without the need for external drivers. A unique feature is the new quasi-resonant peak current mode controller, the NCV1362. This controller holds 86% system efficiency up to 450V input and 78% as input reaches 900V. The NCV1362 controller implements a current-mode architecture operating in quasi-resonant mode that prevents instability and allows for designers to build high-density converters. These high-voltage auxiliary power supplies give engineers with control to regulate the output current to stay constant regardless of input conditions.
ON Semiconductor’s Low-Voltage Power Solutions
The other two solutions recently launched by ONSemi are isolated supplies for IGBT drivers and SiC MOSFETs, the SECO−LVDCDC3064−IGBT−GEVB and the SECO−LVDCDC3064−SIC-GEVB. Both are variations of one another, one is for IGBTs the other for SiC power FETs. These solutions are essentially the backbone of the automotive control system, they are able to provide stable voltage rails from -7.5V to 15V as well as a backup 7.5V rail.
Block diagram of the IGBT solution for gate drivers, the design provides the functional isolation needed for level shifting when used with high−side gate drivers. Image used courtesy of ON Semiconductor.
The isolated supply designed for IGBT-based drivers features a feedback loop signal (1.25 V) realized via an auxiliary winding regulated at 5 V and a voltage divider. With a robust design, this solution is able to step-up, step-down voltages from an input range of 3V to 40V. Designers have the ability to extend battery life with the converter’s low power shutdown mode.
The input isolated SiC-based drivers is essentially the same as the IGBT-based solution but can provide a 20V supply. Both gate drivers utilize ONSemi’s NCV3064 regulator that provides internal temperature reference and are ready to use plug-in solutions for automotive applications. The purpose of the IGBT and SiC drivers is to establish a simple, low component count solution that offers isolation when high-side gate drivers are used within the power system.
Cost-Effective Supplies for EVs and HEVs
The demand for electric vehicles hasn’t skyrocketed due to the average costs. Most manufacturers are pushing for cost-effective, robust designs in order to market more affordable vehicles that would increase the demand curve. ONSemi’s auxiliary power supply units and gate drivers have proven to reduce the need for external components for delivering power to a wide variety of low voltage subsystems while handling 400V-800V input voltage from market standard electric battery systems.