Innovations in low-noise and precision technologies are contributing to the vast performance improvements of sensitive medical, test and measurement, and electric vehicle battery-management systems
In the summer of 2004, a standard ultrasound showed that Steve Schnier and his partner were expecting twins. Weeks later, they were surprised when another ultrasound revealed a third baby on the way.
Steve, a systems engineer in our switching regulator business, suspected that unwanted noise – or signal interference in the ultrasound system – was likely behind the anomaly.
“I never really made the connection until I started working with medical imaging devices and wireless infrastructure, where noise is a big issue,” said Steve, whose triplets are now young adults preparing for college.
Technology has improved significantly in the nearly two decades since Steve’s ultrasound surprise. However, finding ways to mitigate system noise and improve signal quality to enable precision signal chains remains a challenge for design engineers across a range of industries.
Understanding the consequences of noise on system performance
In the operation of complex power systems, silence is golden — but it is far from assured. Noise is an electrical byproduct generated by all components and can arise from multiple sources, including electromagnetic interference (EMI) and thermal heat. It corrupts signals, leading to distortions in measurement that can result in errors, miscalculations or misinterpretations that ultimately affect system accuracy and reliability.
Noise also can render electronic systems more susceptible to external influences such as temperature fluctuations and voltage variations. These external factors can further amplify noise, adding additional inaccuracies.
In sensitive systems such as medical imaging equipment, excess noise can lead to blurry or potentially inaccurate images. Noise can also negatively affect the accuracy and precision of test and measurement equipment, which can lead to inaccurate results.
Building precision into EVs
Noise challenges are particularly salient for automotive engineers designing electric vehicles (EVs) or developing autonomous driving systems where precision signaling is vital for safety and performance.
“In EVs, sensitive systems for safety or parking, which are vulnerable to excessive noise, sit in close proximity to the high-power components that produce the noise,” said Jeff Morroni, director of power management research and development at Kilby Labs, our applied research lab. “This is what our low-noise and precision technologies are attempting to address.”
Sensitive systems need to be robust enough to withstand noise generated by heat and physical stress. The impact of a car hitting a speed bump can produce enough stress to affect signaling accuracy.
Noise can affect the operation of autonomous driving systems, while light detection and ranging (LIDAR) systems can experience “ghosting” — the production of false or misleading signals or images. The lithium ion batteries powering the EV revolution, meanwhile, can become unstable and pose a safety risk if they over-heat.
Power management devices that minimize distortion and reduce noise are used in the signal transmission and conditioning chain, and therefore, are vital for enabling a clear signal. Those same power devices also power the clocking ICs and precision ADCs (analog-to-digital converters) and DACs (digital-to-analog converters) to enable a complete low-noise and high-precision signal chain.
One of the more tangible benefits of reducing noise is improved drive range in EVs. The more accurately that developers can measure voltage signals from EV batteries, the more miles they can run off a single charge. High-precision battery monitors and balancers with the ability to measure down to millivolts (one-thousandth of a volt), such as our BQ79718-Q1, can lead to significant improvements in range.
“We are talking in the ballpark of 10% to 15% improvement — enabled simply by the ability to measure the voltage more accurately,” Jeff said. “That directly translates to a customer value proposition in terms of the cost of batteries.”
Reducing design time and cost with low-noise technologies
Minimizing noise involves a forensic look at every link of the signal chain. Semiconductors inherently generate noise that can affect the performance of other components. However, that noise can be “hushed” using passive filtering, control techniques and other unique process technologies. Additionally, power components such as low-noise low drop-out regulators (LDOs), buck converters and voltage references can also help achieve low system noise.
For decades, low-noise LDOs have been the industry standard for providing low-noise power due to their ease of integration and ability to provide the cleanest and most precise supply rail possible for highly sensitive applications. For example, our TPS7A94 offers the lowest-output noise supply on the market with high-output voltage accuracy and an ultra-high power supply rejection ratio to help generate a clean supply rail that won’t compromise system performance.
Meanwhile, our TPS62913/2 series of buck converters have the ability to reduce noise in power supply architectures without the traditional need for an LDO to regulate the power voltage. And while it may introduce a little more noise than an LDO, it saves space and cost, increases efficiency and reduces power loss and thermal issues.\
Voltage references, a foundational building block in data conversion systems, also have a major role to play in reducing noise. Voltage references require exceptional stability to avoid introducing errors into a signal chain. Our REF70, an ultra-high-precision voltage reference, sets an industry-leading benchmark for low noise, unlocking additional bits from the ADC and enabling precision measurements.
“I would call voltage references the cornerstone of a signal-chain design, because every single component from your ADC to your DAC has to be referenced to a voltage,” said Katelyn Wiggenhorn, a leader for our voltage reference and supervisor business. “Reducing noise is important, because a high amount of noise can cause your system measurements to fall out of specification. When that happens, you have to take your whole system offline to debug and calibrate it. If we can extend that calibration cycle, you’re really giving value to the client with more throughput and less down time.”
While noise is an inevitable byproduct of power supply architecture, by employing our low noise and high precision technologies, engineers can design systems with industry-leading accuracy in a smaller footprint and at lower cost.
“Noise can have significant effects on sensitive systems across many applications – I know firsthand, both as a father of triplets and as an engineer,” Steve said. “We’ve come a long way with technology the past 18 years to help reduce it, but there are still challenges. Our continued innovation will help engineers solve their challenges and lead to substantial improvements in system performance.”