Case Study

TransSiP PI: The Secret of Getting the Most Out of Your System 

The Importance of System Efficiency

Engineers are coming up with innovative ways to use harvestable energy in addition to batteries to power remote or mobile electronics.  The next stage is to transform the energy acquired into a power source that is genuinely useful to the system being powered.  This raises a significant question: System Efficiency. 

System efficiency is not only about the matters of DC-DC power conversion, but also the quality of the power supply bias of the system being powered. Higher signal quality, sensitivity, accuracy, and reliability are all possible because of a good power supply bias (i.e., Power Integrity or PI). In comparison, a system with a poor-quality power supply is more inefficient, consuming more energy on high-power activities.  The efficiency of the system decreases as more error corrections and iterations occur in the processor run time - a concern of performance versus battery life.  A low-quality power supply bias means a decreased system efficiency that is prohibitive to performance, battery life, and most significantly for users - User Experience. 

Why don't advanced smartwatches and sports watches match the accuracy of a basic chest strap?  It is because arterial pulses create signal variations of approximately 0.086dB or less with optical-based cardio monitors - a tiny shift highly susceptible to power supply noise interference. So why does a sports watch need so long to determine its position?  Or, why do sports watches and smartphones have a high rate of returning hundreds of meters off, if not thousands, when locating someone?  The "Find My Friend" app's user experience is one example of a problematic interaction.  One major problem that affects our daily lives is Power Integrity. 

Summary: The Importance of System Efficiency

The Problems of DC-DC Power Conversion 

Noise-sensitive applications, such as location-based services, health monitoring, wireless communication, homeland security, data storage, computing, and many others, require constant supply voltages that are free of noise and other disturbances.  However, converting the source voltage into a clean, stable supply bias for noise-sensitive applications is challenging from the get-go. 

Currently, two techniques are prevalent in the process of DC-DC conversion.  Switching mode employs digital switches to offer the best efficiency, resulting in the least waste of limited battery capacity or precious harvested energy.  However, switching mode and energy harvesting power supplies (SMPS) generate a very noisy supply bias.  The problem will worsen as the switching noise changes phase, which has been coined as Switching Noise Jitter (SNJ) – a dominant noise under weak signal conditions.  The alternative, linear DC regulation, offers a relatively cleaner power supply but at the expense of reduced efficiency.  The problem will get worse as on-chip operating voltages decrease since linear conversion is based on the source-to-supply bias ratio.  Furthermore, simultaneous switching noise (SSN), generally referred to as ground-bounce, increases with I/O activities even with linear DC regulation, which makes conventional filters ineffective in eliminating the noise. 

The lowered operating voltages make a system much more vulnerable to power supply noise.  At the same time, the power-saving duty cycles create transient noise, which makes the power supply noise even more chaotic.  Therefore, system development has been accompanied by increasing complexity in power management design and filter strategies in attempts to minimize the noise footprint.  But the Irvine, TransSIP has found that, in spite of sophisticated filtering, something has always been there.

Summary: The Problems of DC-DC Power Conversion 

How TransSiP PI can Help Achieves System Efficiency and Performance 

The patented TransSIP PI noise reduction technology enables a high-quality DC power source, making it worthwhile to optimize system efficiency and performance for noise-sensitive applications.  TransSIP PI products use a novel circuit topology that actively identifies and corrects a newfound noise in real-time: Switching Noise Jitter, or SNJ, results in a clean and stable power signal.  This allows for the development of power systems with significantly reduced noise footprints.  TransSIP PI technology is an important breakthrough in the field of power management and has the potential to revolutionize the way DC-DC power conversion is performed. 

What is SNJ and why should we care

Switching Noise Jitter, or SNJ, is a previously unrecognized time-domain form of noise found on top of frequency-domain phenomena such as power spectral density, ripple, and harmonics of a switching mode power supply.  SNJ is the dominant noise detrimental to signal integrity during weak signal conditions.  

TransSiP discovered the SNJ noise component during research into sources of instability of GPS systems.  Undetectable using conventional frequency-domain analysis, TransSiP turned to a real-time spectral histogram analysis from Tektronix.  SNJ is a “noise on the noise” but it changes phase on top of the frequency-domain noise of a switching mode power supply.  So SNJ is the occurrences of “noise” moving in time.   

The discovery enabled the development of a novel circuit topology for filtering this "noise on the noise".  It is evident that digital systems run a lot more efficiently under real-world weak signal conditions without SNJ in the power supply bias. 

The benefits of TransSiP PI technology

TransSiP PI products are marketed in Symphony PI DC-DC chipset and Harmony PI filter.  The Symphony offers the highest noise quality of switching mode DC-DC buck conversion from a power source.  While the Harmony filter works with many different DC power sources, it eliminates a broad spectrum of noise in the frequency and time domains without IR drop.  As a result, Symphony and Harmony enable systems to reach exciting levels of signal clarity, sensitivity, accuracy, reliability, and most importantly – User Experience. 

Summary: How TransSiP PI Helps Achieve Optimal System Efficiency and Performance 

Examples of Customer Satisfaction 

Example 1: The Biomedical Benefit 

The diagram below illustrates that wrist-worn optical heart rate monitors (OHRMs) are generally considered less accurate than the basic chest strap HR monitors, notwithstanding that OHRMs are built with multiple LEDs and Photodetectors running with advanced algorithms. 
Such shortcomings of the wrist-worn OHRMs can be attributed to its lower signal-to-noise ratio (SNR), a result of the OHRMs having a noisy power supply bias that causes significant interference toward the LEDs and Photodetectors. 

A traditional approach is to add more LEDs and Photodetectors to the OHRMs, and pump more current to increase the SNR.  But in real-world conditions, it is evident that multiple LEDs (and Photodetectors) and the highest input current (or highest SNR) are not necessarily the most optimal performance.  It is ineffective while detrimentally on power consumption. 

In weak signal conditions, the significance of SNR varies depending on the quality of the dynamic range, especially when the required signal is near to or overlaps with the background noise.  OHRM is an excellent example in this scenario. 

On the contrary, TransSiP PI Enhanced OHRMs offer accuracy equivalent to the chest straps, even with a single LED and Photodetector.  Using a Harmony PI filter is essential to clean out all noise in the supply bias to the LED, AFE, Photodetector, and Current ADC as illustrated in the following diagram. 
The following illustrates OHRMs are considered clinically acceptable, and TransSiP PI Enhanced OHRMs achieved all that. 

Summary: The Biomedical Benefit  

Example 2: The Sports Products Benefit

TransSiP PI technology has proven to be a key enabler in completely autonomous systems and low-power energy harvesting strategies, presenting a combination of very high system efficiencies and extraordinary supply bias quality. For example, the diagram below illustrates that a TransSiP PI Enhanced Sports Watch offers 10 times better accuracy in distance traveled and 25% faster in the power-hungry process than without. 
Matrix Industries is exploiting both the dramatic improvements in power conversion efficiency as well as the substantial strides in system performance that TransSiP PI provides.  This winning combination enables their innovative new designs to operate entirely from the user’s body heat or thermal gradient or plus PV harvesting.  For example, the renowned Power Watch 2 provides the full suite of performance metrics including GPS, cardio monitoring, and the most accurate calorie counter on the market… indefinitely.  This step function is the reduction of energy wasted that realized the first-ever Energy Harvested Full Function GPS Sports Watch: The Matrix Industries’ POWER WATCH 2 represents wearable technology truly “On the Run”. No more running out of battery in the last mile! 

What this has meant to Matrix is summed up by a comment from Douglas Tham, CTO of Matrix Industries: 
"In energy harvesting systems, efficient use of power is the key to real autonomy.  TransSiP PI extends our edge - it gives us the power integrity we need to achieve high performance and ensure that our technologies are fully autonomous, providing the quality of user experience and confidence a consumer needs in making a purchasing decision.  Our vision of ‘zero carbon’ energy is finally becoming reality." 

Summary: The Sports Products Benefit

Conclusion: TransSiP PI is the Key to Getting the Most Out of Your System

With regard to the market for which TransSiP PI is being utilized, significant efforts are being made in the following areas: