The primary function of the Pulsiv OSMIUM MCU is to generate a high power factor while maintaining a high efficiency over the whole load range. Power electronics have one of the most difficult difficulties when it comes to efficiency, which must be increased to fulfil both international standards’ criteria and cut down on power waste to produce more sustainable goods.
Any AC-powered device, from the most basic mobile phone chargers to the most sophisticated and potent SMPS for industrial applications, needs a power supply. All of the power drawn from the AC mains is made accessible to the load in a perfect power supply. In practise, this is only feasible if the voltage and current are in phase. A portion of the energy received by the grid is wasted if current and voltage are out of phase. This work is exactly carried out by the power-factor correction (PFC) stage of a power supply, which aims to come as near as feasible to the ideal scenario, which corresponds to a unity power factor. Today, Cambridge-based firm Pulsiv emerged from stealth status with the release of their power electronics technology. Pulsiv OSMIUM transforms AC to DC with a unique mechanism that comprises charging and discharging a small storage capacitor without the need for a PFC inductor. This solution’s characteristics include a high power factor, consistently high efficiency, and an ultra-compact system design. Utilizing Pulsiv OSMIUM technology may save expenses, improve overall system effectiveness, and aid in reducing global energy consumption.
The clever regulation of Pulsiv
A small group of top experts in sales, product development, and finance developed Pulsiv, a firm founded in 2013 as a spinout from Plymouth University. Engineers at Pulsiv found a novel method of obtaining additional energy from solar panels while researching technology for solar micro inverters. They discovered that the method works with LED illumination, battery charging, and AC/DC conversion by using analogous principles in the other direction. Although Pulsiv still maintains a business section dedicated to solar technology, it has lately expanded to offer power supply solutions.
According to Darrel Kingham, CEO of Pulsiv, “Our product fundamentally comprises of a significant U.S. Tier 1 semiconductor chip to which we add our unique IP.” The Pulsiv OSMIUM microcontroller [MCU], which is the foundation for building power electronics front ends that cover a wide power range, is the outcome. The Pulsiv OSMIUM MCU, which has the primary responsibility for producing a high power factor while maintaining high efficiency over the complete load range, houses all of the essential technologies. A switched current flows via a series inductor in a simple PFC controller, and the power factor may be adjusted by observing the phase change in the voltage and current.
According to Kingham, “Our solution is based on a different methodology, where we manage the charge and discharge of a storage capacitor.” This serves as the foundation for our invention and offers us several advantages beyond only power-factor adjustment. Figure 1 illustrates how PFC may be produced with only a tiny storage X-capacitor that is charged and discharged through the use of an appropriate circuit design (symbolized by switches S1 and S2). The power factor is always maximised by the MCU’s regulation of capacitor charging up to a specific maximum voltage in synchrony with the grid. Furthermore, there is no inrush current when the circuit is first powered up since the current route is fully controlled by the MCU. Because Pulsiv’s method controls the current flowing into the bulk capacitor, it removes inrush currents from the front end of the power supply; the X-transient capacitor’s is the sole inrush. The front-end stage’s DC/DC converter, which comes after it, controls the discharge current from the storage capacitor, which is not controlled.
Cost-saving 160-V capacitors can be used in place of more expensive 450-V capacitors since the controller prevents the voltage from rising too high. Furthermore, you don’t need to store a lot of energy since just the necessary energy is efficiently stored when the grid voltage drops to zero. This enables you to utilise capacitors with a lower voltage rating that are smaller. When using a capacitor in parallel, Kingham explained, “you only need to store a tiny quantity of energy for the time when you need it, while when using an inductor in series, all the energy needs to travel through the inductor all the time.”
The efficiency profile of Pulsiv’s solution is an additional advantage. This converter can sustain a very high efficiency at very low power, in contrast to boost converters, where efficiency tends to decline rather quickly. This is due to the converter’s ability to charge the capacitor solely with the energy required in the low-power zone, when the majority of boost PFCs begin to fail. Active Bridge Control, Configurable Hold-Up, X-Cap Discharge, HVDC Output Selection, a Power Consumption Indicator, and Grid Failure Detection are all supported by Pulsiv OSMIUM technology. These extra features can be chosen as needed to satisfy the requirements of various end applications. Figures 3 and 4 demonstrate how Pulsiv’s technology not only achieves great efficiency but also makes it possible for it to do so while maintaining stability over the whole power range, including low power. Consistent performance and compliance with Energy Star VI regulations can result in up to 99% efficiency. This solution’s use of 95% commodity components to achieve efficiency results in a bill of materials (BOM) that is extremely affordable ($6 to $15) and, therefore, greatly simplifies the process of acquiring such components.
Another important aspect of Pulsiv’s technology is scalability. The needed output power, scaled from 1 W to 10 kW+, may be provided by the same circuit by replacing just three crucial components (one inductor, one MOSFET, and one capacitor). This is possible because the MCU does not control the output power (all other components remain unchanged). When compared to other semiconductor firms’ reference designs, Kingham noted, “our entire flyback 150-W design requires one-third to half less components in the BOM, and our design is quite straightforward.”
PSV-AD-150 and PSV-AD-250 Starting today, two Pulsiv OSMIUM controllers will soon be available to support applications demanding up to 250 W of power. To make the design process simpler, full circuit configurations for the Pulsiv AC/DC front end will be made accessible. A complete schematic, BOM, Altium file, and component calculator are among them. Both a 75-W and a 120-W 48-V flyback reference design that have an improved DC/DC stage are being released at the same time. These will be followed by a full 150-W USB-C reference design and a 150-W 20-V interleave PSU reference design. The portfolio will be finished by the end of this year with a full 500-W current-source PSU reference design. The creation of a 240W interleaved flyback is now under process, and efforts are being made to present reference designs with even greater power capacities. According to Kingham, “We want to offer something on the market that is more efficient, that satisfies Energy Star criteria, that is reasonably inexpensive to produce, and that anybody can embrace.” The three primary use cases for which Pulsiv technology is appropriate are as follows:
- Customers typically purchase integrated power electronics, which are high-volume applications, instead of commercially available power supply since they are either too large or too costly.
- Manufacturers of switch-mode power supplies that utilise Pulsiv technology for enhanced power, density, and performance
- Completed solutions, mostly centred on USB applications and strong power banks
Engineers may test Pulsiv OSMIUM technology on the PSV-AD-250-DS development system, and by attaching an appropriate DC-DC converter, a whole power supply prototype will be created. To demonstrate what is possible when Pulsiv OSMIUM is paired with a carefully chosen DC-DC converter, entire reference designs are being made freely available online on the company’s website.