Analog Devices Breaks New Ground For Vital Sign Detection And Portability In Patient Monitoring Medical Equipment

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ADI’s new JFET-input in-amp improves performance and shrinks package size by 50%, increasing channel densities in patient monitors and portable medical electronics.

Analog Devices continues its history of serving the medical electronics industry by introducing the AD8220 JFET-input instrumentation amplifier. The AD8220 enhances the detection of patient vital signs in both fixed-line and transportable electrocardiograms (ECGs), electroencephalograms (EEGs) and other types of patient monitoring devices. Housed in an 8-lead plastic MSOP (mini-small-outline package) that is half the size of competing devices, the AD8220 in-amp allows designers of medical equipment to break new ground by freeing up additional board space to significantly increase ECG and EEG channel density, allowing for smaller medical monitoring systems. Monitoring equipment with high channel density also gives medical professionals more measurement points for very small signals like heart pulses and brain activity while protecting patient vital signs from electrical interference. In addition, the AD8220 operates on a single low-voltage power supply that draws only 700 ВµA, making it ideally suited for use in portable patient monitoring systems.

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The AD8220 features an extremely low input bias current of just 4 pA (pico amps), which is less than half the level of competing components and addresses a significant source of signal error in precision instruments. The AD8220 also achieves an 80 dB common mode rejection ratio (CMRR) up to 10 kHz (G=1), while competing in-amps guarantee only 72 dB to 200 Hz. With significantly lower input bias current and higher CMRR, health care professionals can now measure heart pulses, electrical brain waves, and other patient vital signs at previously undetectable levels. The high CMRR, meanwhile, shields these signals from outside interference by rejecting electrical noise from other parts of the human body.

About the AD8220
With JFET (junction field effect transistor) inputs, the AD8220 in-amp achieves a guaranteed input bias current of 20 pA, maximum, and 4 pA, typical. It specifies a 1-nA input bias current over temperature, and 2 ВµV/В°C input offset voltage temperature drift. The rail-to-rail output of the AD8220 allows designers to improve dynamic range by increasing the gain further before reaching the supply rails. Furthermore, the AD8220’s 80 dB CMRR (G=1) over frequency ensures that only the desired signals are monitored and unwanted common-mode signals are rejected.

Applications
The AD8220 is ideally suited for patient monitoring systems, where its small size, low current noise and low input bias current increase the sensitivity and noise rejection of fixed-line and portable medical equipment, such as ECG and EEG systems. The low input bias and high CMRR characteristics also make the AD8220 a fit for industrial automation applications, such as electrometers and other precision instrumentation systems where extremely small currents must be measured in electrically noisy environments.

Fujitsu Laboratories and imec Holst Centre Develop Wireless Transceiver Technology

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Complies with the 400 MHz-band international standard while consuming 1/10th the power of previous models, lightening the burden on patients who use sensors

Fujitsu Laboratories Ltd. and Imec Holst Centre announced that they have developed a wireless transceiver circuit for use in body area networks (BAN) for medical applications that adheres to the 400 MHz-band international standard.

While the subject of high expectations for medical applications, wireless monitoring of brainwaves or other vital signs has in the past required over a dozen milliwatts (mW) of electric power. Now, however, by optimizing the architecture and circuitry, Fujitsu Laboratories and imec Holst Centre have succeeded in reducing the electric power requirements of wireless transceiver front-ends, to just 1.6 mW when receiving data and 1.8 mW when transmitting.

This technology extends by approximately ten-fold the battery life of conventional sensor products used for patient monitoring. This cuts the frequency of battery replacement or recharges, lightens the burden on patients, and increases the work efficiency of medical practitioners.

Based on this joint research into wireless transceiver technology, Fujitsu Laboratories plans to apply it to non-medical uses, as well, such as to the monitoring of societal infrastructure, thereby further enhancing network front-end interface technologies.

Details of this technology were announced at the IEEE International Solid-State Circuits Conference 2014 (ISSCC 2014), which opened February 9 in San Francisco (ISSCC Presentation 9.7)

Background

In the field of healthcare and medicine, BAN have attracted attention for their potential application in collecting patient-monitoring data via a wireless network of sensors placed on the patient’s body (Figure 1). The various sensor nodes that make up the BAN all need battery power, and to make the system as convenient as possible for both the patient and medical practitioners, there is a need to extend battery run-times so the required frequency of battery replacement or recharging is held to a bare minimum.

Technological Issues

The component in the sensor node that draws the most power is the wireless transceiver circuit, so to extend battery life, the power demands of that part need to be reduced. The challenge has been in developing a compact, low-power transceiver that can support the variations in transfer rates which medical systems require, without adding any new circuitry.

About the New Technology

This research project stipulated a 400-MHz wireless specification compliant with IEEE 802.15.6, the international standard for BANs, and support for two independent modes: a 4.5 Mbps high-speed mode capable of transmitting brainwaves, images, and other data needed in medicine, and an 11.7 kbps low-speed, low-power mode for low-power operations when sensor nodes are on standby.

Two points about the new technology are as in the figure below:

1. Digitally controlled receiver technology

Simplifying the architecture of the transceiver circuit as much as possible has resulted in lower power demands. The digitally controlled transceiver circuit uses a programmable structure that can change its circuitry characteristics to support different phase and frequency modulation methods in adherence to BAN international standards. The receiver consists of a low-noise amplifier, mixer, low-pass filter, and AD converter, and uses a direct-conversion technique that extracts the baseband signal directly from the incoming wireless signal. The use of this technique, along with minimized power requirements for all of the constituent circuitry, made it possible to greatly reduce power requirements. The 4.5-Mbps high-speed mode optimizes the frequency characteristics of the low-pass filter and AD converter through digital circuits. In the 11.7-kbps low-speed, low-power mode, the low-noise amplifier operates at lower power, which degrades its sensitivity, but digital processes compensate for this.

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2. High-speed digital three-point modulation technology

Using a transmitting mixer in the transmitter makes it easier to implement high-speed mode, but mixers and their driver circuitry are known to greatly increase power demands. A combination of the following three techniques resulted in low-power operation.

  • Rather than using a transmitting mixer, the circuitry uses a digital three-point modulation scheme in which a PLL, which generates the wireless signal from the digital circuit, takes as input high-frequency and low-frequency signals, and, similarly, the amplified transmit signal is input to the power amplifier.
  • To implement the high-speed mode using digital three-point modulation, a dual-varactor circuit technology was developed that, when in high-speed mode, increases the variation in the varactor’s capacitance at the VCO, which takes the high-frequency modulated signal as input.
  • For low-speed/low-power mode, a low-power technology was developed that reduces the VCO modulation circuit’s baseline current by 90% while still allowing modulation.

These technologies support both a low-speed mode and high-speed mode with more than 300 times the transfer rate, resulting in a maximum power consumption of 1.6 mW when receiving and 1.8 mW when transmitting.

Results

This transceiver circuit for healthcare applications has potential applications beyond patient monitoring, and could be used as a sensing front-end interface for medical-device management. In both applications, the lifespan of the batteries used in the sensor nodes will be greatly extended, relieving the burden on patients and making operations more efficient for medical practitioners.

Future Plans

Based on the newly developed wireless transceiver technology, Fujitsu Laboratories plans to extend its application beyond medicine and healthcare, applying it as a fundamental network front-end technology for use in such areas as agriculture and livestock management, monitoring of societal infrastructure and structures, factory monitoring, and environmental monitoring.

MobileECG may be next great open hardware project

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There isn’t much open hardware medical instrumentation projects that can be considered completed and reliable. MobilECG project could pretend to be one that could compete with medical grade devices. Actually Péter, the founder of project, intended to collect decent amount of funding to get medical certification. But campaign didn’t went as planned, so he decided to make project open. Since the most of work is already done it would be sad to see project die. The decision to make it open is plausible and maybe it will completed with help of community.

MobilECG is very compact device that can measure ECG using 12 leads. The ECG signal is digitized using ADS1278 eight channel ADC from Texas Instruments. For interfacing and communication to host there are two Atmel AVR micros used – ATtiny24 and ATUC64D4. Schematic is developed using KiCAD software. Firmware isn’t complete – only minor functionality with several known bugs. Anyone with biomedical engineering knowledge will definitely see the potential of this device that can be attached to any device like PC, android or other and explore own ECG signals.

The software is licensed under WTFPL, the hardware under CERN OHL 1.2. There is no warranty, and I have no liability for anything related to mobilECG. Only put the electrodes on people if you are 100% confident in what you are doing.

Note: the design is functional  but unfinished, it needs additional work before it can be certified. There are also some known bugs in it. Most of the software is unimplemented. If you have questions, contact me at peter dоt isza аt gmail dоt com.

ECG was a revolutionary invention in the recognition of these life-threatening conditions. Since its introduction, ECG has had one of the biggest impacts on modern medicine, just like antibiotics. We believe that with our new, 21th century solution more people can have access to clinical-grade electrocardiography than ever.

Regular medical screening plays an important role in prevention. Proper screening requires 12-lead diagnostic ECG machines, which are usually expensive and hard to use.

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MobilECG is different. Read on to find out how mobilECG can help you and your loved ones.

Projected technical specifications

  • Supported operating systems
    • Windows (XP+)
    • OSX 10.6.8+
    • Ubuntu
    • Android (Only with USB OTG support. The mobilECG wireless adapter (described later) will support every Bluetooth device.)
  • Pacemaker detection  Yes
  • Lead-off detection  All leads except for RL
  • Defibrillator protection  5 kV
  • Patient protection  4 kV R.M.S.
  • Peak-to-peak noise  < 12 µV
  • CMRR  > 100 dB
  • Output sampling frequency  500 Hz
  • ADC resolution  50 nV/bit
  • Electrode offset  ± 300 mV
  • Dynamic range  ± 300 mV
  • Standards  IEC / ANSI ES 60601-1, 60601-1-2, 60601-1-6, 60601-2-47

MobilECG brings diagnostic ECG recording to patients, and is a powerful diagnostic tool for doctors, providing frequent high-quality data simpler than ever before.

  • MobilECG is a smart cable that turns your computer or tablet into a clinical-grade diagnostic ECG machine.
  • There is no need to install drivers or applications on your PC or Mac. Just place the electrodes, plug in the USB, start the portable app and you are ready to go.
  • The free software will guide you through the measurement with voice instructions. It will detect common mistakes, for example, wrong electrode placement or improper contact.

ON Semiconductor Announces High Performance System-in-Package (SiP) Solution for Precision-Sensing in Portable Medical Devices

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Semi-customizable, power efficient SiP solution enables miniature sensing systems ideal for mHealth applications including glucose monitors, heart rate monitors, and electrocardiogram analyzers

ON Semiconductor has responded to rapidly-evolving product development demands within the portable medical market by introducing Struix, a semi-customizable System-in-Package (SiP) solution for precision sensing and monitoring in a variety of mobile medical electronics including glucose monitors, heart rate monitors and electrocardiogram analyzers.

Struix, which means “stacked” in Latin, utilizes advanced die stacking technology to integrate a custom-designed analog front-end (AFE) on top of an industry-leading 32-bit Application Specific Standard Product (ASSP) microcontroller (ULPMC10), to form a complete miniature system. By using standard and customizable components, Struix offers medical device manufacturers the design flexibility required to create unique medical sensor interface applications while improving time-to-market and cost-effectiveness.

The ULPMC10 microcontroller element of Struix processes signals using an industry-leading 32-bit ARM® Cortex®-M3 core capable of running up to frequencies of 30 megahertz (MHz). The microcontroller incorporates 512 kilobytes (kB) on-chip Flash memory and 24 kB SRAM memory to store critical program and user data. Designed to improve battery life in portable devices, ULPMC10 offers superior performance with minimal dynamic and static power demands. Through on-chip charge pump-based power conversion and regulation, the microcontroller can operate at a current consumption of less than 200 µA/MHz. While in standby mode, current consumption remains below 500 nanoamperes (nA), a critical parameter for low-duty cycle medical devices.

The system’s advanced power management subsystem monitors the device for fail-safe operation with a wide variety of battery voltages without requiring external components. The microcontroller also includes a12-bit analog-to-digital converter with three multiplexed inputs, a real-time clock, a phase-locked-loop, and a temperature sensor. To simplify product development, ON Semiconductor offers a comprehensive and easy-to-use suite of development add-ins for IAR Systems to support the ULPMC10 microcontroller, including CMSIS based software interfaces.

Using ON Semiconductor’s custom chip engagement model, medical device manufacturers can take advantage of an extensive portfolio of intellectual property and design experience to meet the stringent feature and performance- level requirements of medical sensor applications.

ZMDI releases the versatile ZSSC3018 High-Resolution 18-Bit Sensor Signal Conditioner for high-accuracy amplification and analog-to-digital conversion of a differential or pseudo-differential input signal

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ZMD AG (ZMDI) announces the new ZSSC3018 High-Resolution 18-Bit Sensor Signal Conditioner (SSC). As a global supplier of analog and mixed-signal solutions for automotive, industrial, medical, information technology and consumer applications, ZMDI is pleased to introduce an SSC designed for high-resolution sensor module applications. The ZSSC3018 is available in a PQFN24 package.

The ZSSC3018 can perform offset, span, and 1st and 2nd order temperature compensation of the measured signal. Developed for correction of resistive bridge or absolute voltage sensors, it can also provide a corrected temperature output measured with an internal sensor. The ZSSC3018 has calibration coefficients that are stored on-chip in a highly reliable, non-volatile, multiple-time programmable (MTP) memory which enables simple programming via the serial interface. The ZSSC3018 provides accelerated signal processing, increased resolution, and improved noise immunity in order to support high-speed control, safety, and real-time sensing applications with highest requirements for energy efficiency.

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Key Features

  • Flexible, programmable analog front-end design; up to 18-bit analog-to-digital converter (ADC)
  • Fully programmable gain amplifier with gain range from 6.6 to 216 (linear factor)
  • Internal auto-compensated temperature sensor
  • Digital compensation of individual sensor offset, 1st and 2nd order sensor gain, and 1st and 2nd order temperature gain and offset drift
  • Programmable interrupt operation
  • High-speed sensing: e.g., 16-bit conditioned sensor signal measurement rate > 500/s
  • Typical sensor elements can achieve an accuracy of better than ±0.01% full-scale output
  • Operating temperature range: –40 °C to 125 °C
  • Supply voltage range: 1.68 V to 3.6 V
  • Low typical current consumption: ~1.0 mA in operating mode; 50 nA in sleep state at ≤125 °C; 20 nA in sleep state at ≤85 °C

Typical Applications

  • Portable navigation systems
  • Industrial pressure sensing
  • Pneumatic and liquid pressure sensors
  • Weather forecasting systems
  • Fan control
  • High-resolution temperature measurements

Availability

The ZSSC3018 is in full production. Parts and evaluation kits are available from ZMDI and can be requested through the ZSSC3018 Dashboard as well as its distribution partners.

MicroWave Technology, Inc. releases two pre-amplifiers for MRI coil applications

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MicroWave Technology, Inc. a division of IXYS Corporation released two pre-amplifiers for MRI coil applications.

The MSM series pre-amp has a 0.45 dB noise figure and a 28 dB gain at 1.5T (64 MHz), 3T (123-128 MHz), and 7T (298 MHz) frequencies. It has an excellent linearity of 20 dBm IP3. The MSM pre-amp is in a miniature package of 0.43 x 0.36 inches. The MPE preamp is targeted for 3T (123-128 MHz) applications and it has a noise figure as low as 0.4 dB with a 27 dB gain and an excellent 20 dBm IP3. It also has an impressive input power protection as high as 30 dBm. Both pre-amplifiers are built using advanced low noise GaAs devices and components with very low magnetism, a critical requirement for MRI coil applications.

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“The MSM series pre-amp is housed in a miniature package of 0.43 inch × 0.36 inch and will be an ideal choice for MRI coils with a large number of channels. The MPE pre-amp is targeted at the low cost MRI coil market while still maintaining excellent RF performance,” said Dr. Greg Zhou, the General Manager of Microwave Technology, Inc. “These two pre-amplifiers are the newest additions to our pre-amp product family. As a major pre-amplifier supplier to major MRI equipment manufacturers in the past 15 years, we are committed to support our medical equipment customers so they can meet their latest requirements.”

A ‘Medical-Grade’ Motion Sensor from STMicroelectronics Jumpstarts Creation of New Implantable Applications

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STMicroelectronics has introduced the MIS2DH, an ultra-low-power 3-axis accelerometer specifically designed for medical applications, including implantable devices classified by U.S. Food and Drug Administration (FDA) as Class III. ST has many years of experience in developing custom motion sensors for leading medical-equipment manufacturers and the MIS2DH distils this expertise into an off-the-shelf solution that can enable functions such as activity monitoring and posture sensing to be included in a wide range of medical applications.

Implantable medical devices such as cardiac pacemakers, ICDs (Implantable Cardioverter Defibrillator), and neurostimulators have been successfully used for many years to prolong the lives of patients with heart problems or to make life better for people with chronic pain conditions. Today, there is a growing interest in the medical world in exploring how new implantable devices could help treat other chronic problems such as high blood pressure, epilepsy, and tremor-related conditions. For most of these applications, an embedded accelerometer capable of measuring the activity and posture of the patient is important to manage the stimulus delivered by the implantable device and therefore to improve the effectiveness of the treatment and the wellbeing of the patient.

The MIS2DH accelerometer has been developed and produced in full compliance with the rules of ST’s medical domain, a self-regulation that ST adopted in 2012 to secure the development and manufacturing flow for products intended for use in sensitive medical applications.

Key technical features of the MIS2DH include:

  • 3-axis accelerometer;
  • ultra-small size (2×2×1 mm);
  • ultra-low power consumption (down to 2 μA in low-power mode);
  • ±2g/±4g/±8g/±16g selectable full-scale;
  • 8-, 10- and 12-bit operating modes;
  • 1 Hz – 5 KHz output data rate;
  • FIFO buffer and programmable interrupt to minimize system power consumption;
  • I2C/SPI digital outputs;
  • 1.71 -3.6 V operating voltage.

The MIS2DH is available now in volume. Please contact your ST sales office for pricing options and sample requests.

Roentgenoscope for hybrid operating room

MODEL XR-800

It’s a reliable portable roentgenoscope, consisting of the source of X-ray radiation, X-ray image intensifier and high-voltage power supply. In the device there are used original X-ray image intensifier on the microchannel plate with high efficiency, high-resolution, and adjusted wavelength in the wide range. The device is designed as comfortable for simultaneous operations of various medical devices, such as tomographs, endoscopes and life support surgical consoles in the modern hybrid operating rooms.

General characteristics:

  • Power capacity: 60 VA
  • Weight – 10 kg.
  • Voltage: AC:50~60Hz,100~250VAC
  • Image resolution: ≥30 px/cm
  • Inage export on the other display– till 3 screens
  • Penetrating rays — <1 mGy/hour (50cm from the source <1mGy/hour (50cm from the source).

Magnito-resonance removable tomograph

MODEL МРТ (MEDICAL WAVE)-2000

This device is designed in accordance with the corresponding required contemporary visualization centers criteria. New levels of automation due to the software support plus the new module environment of the working place improve the operating efficiency and progress of works. The newest computing components and equipment provide the high level of images capture rate, resolving capacity and signal/noise ratio. It has the extended rating of available leading clinical treatment.

General characteristics:

  • Type of magnet – F 2000
  • Magnetic field induction —0,6 Tesla
  • Max. Field of vision — 600 mm
  • Image acquisition matrix from 64х64 till 512х512
  • Modifications – 2/3 transferable racks for the needs of the various medical hospital services
  • Weight – 30-50 kg.