Primary side regulation is critical to the expansion of the IoT movement
To meet this goal, there must be a net zero anthropogenic greenhouse gas emission during the second half of the 21st century. Under current energy usages, this is a tall order.
In fact, consumer demand is pushing the dial the other way. The so-called ‘Internet of Things’ (IoT), is expected to connect an estimated 30 to 90 billion electronic devices by 2020. The IoT will be made up of a network of connected things such as sensors, monitors, measuring devices, computing devices, and wearables of all sorts (think small, integrated electronics). All of these ‘things’ will require additional power. At present, the global electric grid would have to expand by two times with current power supply efficiencies in order to meet this demand. So, the question is how these billions of things will be powered efficiently enough that world governments can meet the Paris Agreement targets and put a hold on global warming.
Traditional power supply technology, popular for the last 20 years, uses flyback topology and secondary feedback control through opto-isolation, which has impeded the full deployment of the IoT. This technology contains too many components, which requires a large footprint – and each electronic part (discretes) presents its own drag on energy efficiency. Therefore, ‘parts reduction’ is one key element to increasing the efficiency of things powered by the grid. In addition, the power supplies for IoT applications need to be able to fit into a small space and should be highly efficient.
Moreover, while power supplies used to be the last subsystem engineered, now an energy-efficient power supply is becoming a prerequisite for any electronic device coming into the market. IoT devices are no different. Consumers want to reduce their monthly energy bills, while governments and utilities want to limit the demand on the grid and its impact to global warming, with the additional burden of IoT devices. To accomplish this, a new approach is needed.
Developed with an eye on the power demands of the future, there is an alternative that is showing promise – TRONIUM Primary Side Regulation (PSR). PSR helps reduce the part count in an under 50 W power supply from the typical 48 to 50 in a typical flyback configuration to less than 25. The result? Less expensive, highly efficient and smaller power supplies.
Lower part count means not only a lower overall cost in end applications but an extreme reduction in size. For example, a typical 60-inch television has over 500 parts in it – 300 electronic parts and 200 mechanical. The size reduction benefits of the TRONIUM PSR solution promise to reduce part count by up to 90 percent. This part reduction is of extreme importance for the sensors and small IoT devices that will be hooked up directly to the grid, especially since TRONIUM allows them to be connected, monitored or controlled either wired or wirelessly.
PSR technology achieves three main goals: runs at over 90-percent efficiency at very low-medium-high load currents and provides almost zero load at a half a milliwatt of standby power. This, in turn, helps consolidate a fragmented industry by using fewer discrete parts – as currently it typically takes fourteen or more vendors to provide all of the parts to a power supply. Cutting the number of parts in half, partly by eliminating the opto-isolation parts, not only reduces the size of the footprint but also simplifies the inventory and design side of the process.
Let’s take a closer look.
Out with the old…
As previously mentioned, the power supply solution commonly used in the industry today is flyback topology and secondary feedback through opto-isolation – typically with 9 to 11 parts that support optocouplers, which are electronic components that connect two separate electrical circuits by means of a light sensitive optical interface. An optocoupler includes an LED, which produces infra-red light and a corresponding semiconductor photo-sensitive device that detects and interprets the emitted infra-red beam. In this fashion, an electronic signal can come from the secondary side of the power supply circuit to the primary side of the circuit without breaching the transformer isolation barrier.
The signal is transferred from the secondary side circuit to the primary side, providing a feedback loop to modulate the pulse duty-cycle and provide regulation. It is this feedback loop that maintains a constant current or voltage output. These typical opto-isolation devices contribute to high component count and provide less efficiency.
The opto-isolation topology requires numerous components – error amplifiers, phototransistors, and optocouplers – which necessitate a larger footprint. In addition, secondary side regulation results in output current sensing loss, so there is a lack of efficiency in the design. In fact, flyback converter technology is least efficient at the light to medium loads required by these small, integrated electronics.
And in with the new…
PSR is a new primary side sensing technology that reduces the number of components and increases the efficiency of the power supply. This technology is essential to the future of the IoT. PSR reduces part count and achieves a smaller footprint and higher efficiency by eliminating the feedback from the secondary side of the circuit and/or transformer. Instead, PSR regulates output voltage and current by sensing both the current and voltage reflection from the primary-side inductor windings only. Others have attempted primary side regulation, but their technology still needs an additional microchip and a tertiary (third) transformer winding to work, which adds back to the part count. In that type of Primary Side Sensing configuration, information from the auxiliary, or tertiary, winding is sampled. The efficiency of that configuration is also highly dependent on a good coupling between the auxiliary winding and the secondary winding.
As an alternative, the new product, TRONIUM PSR, removes the need for secondary side sensing, which reduces the amount of circuitry required and does not need a third transformer winding. The TRONIUM PSR works with a forward convertor/controller configuration, which is more efficient than the typical flyback configuration due to the coupling of the topology with the use of TRONIUM capacitive pre-regulation voltage reductions, where the voltage is reduced to near target voltage levels before a transformer is introduced for isolation.
In this instance, the TRONIUM PSR technology senses from the primary side winding and the driver FET directly, using a new complex algorithm equation to account for the full depletion of the secondary winding energy plus secondary part losses. The information is then used to regulate the secondary output voltage by Pulse Width Modulation (PWM). PWM is a method that takes digital information and transports it with an analog like pulsing signal. The PSR can adjust the PWM based on the output load required, which results in an energy savings.
Since TRONIUM PSR technology does not require optocouplers or error amplifiers, there are fewer components required that have to be powered. The elimination of flyback conversion and opto-isolation circuits reduces the part count by 50 percent – from about 50 components down to 25. The entire TRONIUM power supply, called Power Supply System on a Chip(PSSoC) has an efficiency of 92 percent at low loads, even during stand-by mode when the system is simply idling.
With ‘Dial-a-Voltage’ technology, this chip can be configured to work with different voltages and can fit into existing power supply topologies. Voltage outputs between 1.7V and 48V can be achieved using the same chip from inputs ranging from 90VAC to 260VAC. This ‘Dial-a-Voltage’ feature maximizes the efficiency by setting the output value for each application’s requirements and eliminates the need for more than 2,500 different power supply options currently in the market to meet the variation in voltage requirements.
PSR coupled with a forward controller topology will play an important role in the burgeoning IoT market, as it is able to provide high power supply efficiency at light and medium loads. The components fit in a smaller package due to the removal of the secondary winding circuitry and the auxiliary winding circuitry. This reduces the cost-to-market for new IoT products. PSR solves the problems of traditional secondary feedback technology while meeting the strict output current regulation required by the portable electronics market.
Semitrex has recognized and meticulously planned for the impending explosion of IoT devices. TRONIUM PSR addresses the demand for power that is steadily growing each year – with no end in sight. It’s this forward-thinking approach that enables a connected, environmentally friendly, energy efficient future.
About the author
Michael Freeman serves as Semitrex’s CEO/CTO and is the founder and principal inventor of its new technology, which changes the power conversion dynamic by bringing over 90% efficiencies to the market in a single module. His innovations won Semitrex a 2015 Frost & Sullivan New Product Innovation Award. Michael’s inventions and business acumen have been the foundation for numerous successful start-up tech companies over the last 25 years. He holds dozens of issued patents in the mobile video, smart grid, power supply, nanotechnology, and chemical industries. Michael has over 80 patents pending worldwide including patents in the credit card processing industry. In the 1990s, he led a team of inventors who developed a two-time Emmy Award winning Mobile Video streaming technology, which became the foundation for 802.11(n) IEEE ‘MIMO’ standards. Licensed by virtually every cell company that existed at the time, these Mobile Video technology and patents were ultimately purchased by Samsung, and were asserted in the Apple vs. Samsung litigation, in which Michael testified as the first ‘smart phone’ and ‘mobile video’ technologies invented. Michael also co-invented a Mobile RFID location/navigation/asset tracking technology for people, robots and drones that resulted in three U.S. patents issued with continuation patents pending.
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