Using SoCs for portable medical equipment

Using an SoC-based device in a blood pressure monitor simplifies design to a great extent. An SoC can integrate the high-gain instrumentation amplifier needed for the design. Oscillatory pulses can be extracted using integrated analog/digital filters. The configurable ADC inside SoC can be used to digitize data. The integrated CPU core provides the required processing power to handle advanced processing algorithms. Such a device can also integrate a segment LCD driver for the display, EERPROM for data logging, a real-time clock for time-stamping, Full speed USB to serve as a PC interface, DMA to offload the CPU, and capacitive touch sensing capabilities to replace mechanical buttons. Timers inside the SoC can be used to calculate the heart rate and to handle safety functionality, and integrated pulse width modulators inside the SoC can be used to control the motors. SoCs also feature wide operating voltage and lower current consumption, characteristics which are ideal for battery-operated devices.

For an infrared thermometer, SoCs also integrate the amplifiers and ADC needed to detect microvolt variations. The SoC’s internal precision voltage reference provides a stable and accurate reference for sensors. Other functionality SoCs integrate a segment LCD driver, EEPROM, RTC, USB interface, capacitive touch sensing, etc.

As discussed above, SoCs integrate most of the peripheral components required by portable medical electronics applications. This not only reduces the number of external components required, it protects analog IP as well since all the analog components are integrated into the chip. Fewer components mean simpler PCBs, shorter design time, and faster time to market. The power of different peripherals inside the chip can be managed individually in different modes so system power management is made simpler and more efficient. Reconfigurability of SoCs chips also reduces the cost and time of redesigning or changing a design over time. More than anything, using SoC architectures makes FDA certification simpler by reducing the bill of materials. Portable medical electronics equipment of all types – glucose meters, pulseoximeters, portable ECG devices, etc. – can be implemented using SoCs.

As an example, Cypress’s PSoC 3/5 products (Programmable System on Chip) are tailor-made for portable handheld applications like Blood Pressure Monitors, Blood Glucose Meters and Pulse Oximeters. The PSoC3/5 integrates an 8051/ARM cortex M3 core running at 33 MIPS and 100 DMIPS, amplifiers, dedicated digital filter blocks, configurable Delta Sigma ADC, integrated LCD driver that can drive a maximum of 736 segments, capacitive sensing for touch buttons and proximity detection, 2KB of EEPROM, Full Speed USB 2.0, and various other functions, thereby enabling true single-chip solutions. This, combined with the PSoC Creator IDE which has pre-programmed configurable IP modules for each function, gives product designers all the tools they need to design a small form factor, highly programmable end product with a very short design cycle.

Overall, using SoCs in portable medical electronics applications makes design simpler, protects IP, and provides novel and unique methods to implement product-differentiating functionality and make FDA certification simpler.

See related links:

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