How Keysight is assisting with battery life optimisation in implantable medical devices
Heart disease continues to be a major health problem all over the world with the trend toward implanted medical devices applies to patients with cardiovascular diseases.
Patients with atrial fibrillation and flutter may benefit from an implanted cardioverter defibrillator (ICD). Pacemakers and ICDs both run on battery power and a depleted battery can be dangerous to the patient. Fortunately, most modern pacemakers and ICDs have low battery warnings that allow the patient to plan for a replacement surgery ahead of the actual battery failure.
Costs of Failed Batteries
A depleted battery can mean the difference between life and death, so a timely device replacement is critical. Ensuring that a device has a long battery life is crucial in modern medical practices due to the costs involved in replacing the batteries. It isn’t as simple as taking the back off the device and putting new batteries in, especially when the device is surgically implanted into the patient.
There are many costs to consider, including the cost of the surgeon, the surgical suite and equipment, surgical nurses, the anaesthesia and anesthesiologist, the recovery room or hospital room, and the follow-up care and supplies.
Current Measurement Instruments
To ensure long battery life for medical devices, design and validation can choose from many hardware tools that measure current. One of the most common tools is the digital multimeter (DMM), which is on almost every hardware engineer’s bench.
Digital Multimeters (DMM)
Keysight’s DMM range are good for measuring low current levels very accurately and are also a good general-purpose measurement tool for voltage, resistance, diodes, and more. One disadvantage of the DMM is that it lacks the bandwidth to capture fast transients accurately. It also may not have sufficient dynamic range to capture transitions between low-current sleep modes and relatively high current active modes.
DC Power Analyser
The DC power analyser is more expensive and less common than the DMM, but it has significantly better bandwidth. As a modular product, it is more flexible than the DMM and some of its modules include source-measure units (SMUs) with seamless ranging that can measure sleep and active modes without the glitching associated with range changes.
Oscilloscopes
The oscilloscope is another commonly available instrument, and with purpose-built current probes, it can give very good current measurements. It lacks the source-measure and e-load capabilities of a DC power analyser, but it has much higher bandwidth and more triggering capabilities.
Device Current Waveform Analyser
The device current waveform analyser is at the high end of current measurement devices. It has a use model like an oscilloscope, high current measurement bandwidth, and excellent accuracy for measuring low currents.
Turning measurements into Insights
While all the instruments listed above can gather large amounts of data accurately, the data alone is not sufficient to provide the insights engineers need to optimise their designs. All that data must be quickly analysed by sophisticated firmware and software that produces engineering statistics and clear graphs to reveal important information at a glance.
Once you have gathered a large amount of data via data logging, you can use that information for more than battery drain analysis. This could indicate an intermittent defect in the hardware – it could be a firmware bug, or it could be caused by malware, such as a Trojan lurking in the device.
Data logging software
Data logging software is an important tool. Implanted and body-worn medical devices often have behaviours that vary widely depending on the severity of the patient’s condition and the environment inside the patient’s body. For devices that communicate via RF signals, even electromagnetic conditions outside the patient can lead to excessive charge consumption, as devices facing difficult RF coexistence challenges may face multiple retries to ensure data is successfully transmitted.
Event-Based Power Analysis Software
Another type of software that helps engineers understand device behaviour is event-based power analysis software. This software is part of an IoT device battery life optimisation solution, and it correlates charge consumption with RF and DC events. It then analyses that information to estimate battery life and identify the key events in a device that consume large amounts of time and battery charge.
Implanted devices can help people with heart issues, and longer battery life can benefit patients in numerous ways. Keysight’s hardware and software solutions, such as IoT device battery life optimisation solutions, device current waveform analysers, and event-based power analysis software can help medical device engineers provide significant benefits for patients and medical professionals.
Keysight Technologies is a leading manufacturer of test and measurement hardware and software for benchtop, modular, and field instruments, including oscilloscopes, multimeters, logic analysers, signal generators and spectrum analysers. As a Keysight Premium Plus distributor, our team of experts have enhanced product knowledge and can offer demonstrations and technical insight into an expanded range of Keysight equipment.