Portable insulin pump system design strategies (1)

Insulin pump is a portable medical equipment, in the United States, its design and manufacture of the United States food and Drug Administration (FDA) of the regulation.

This means: its design and construction must follow the exact requirements of the process; its performance must meet strict document management, development, testing, production, testing and onsite maintenance requirements. As shown in Figure 1, you must also include comprehensive self test and fault display function, and thus require additional circuits as well as the use of a self-inspection function of the device.

Portability

Insulin pump is worn by the device, therefore, must be very small and light (Figure 2).

Its volume is usually about 2 × 3 × 0.75 (5.7 × 7.6 × 1.9 cm), weight of 2 and 4 ounces (57 g and 113 grams). The overall requirements designers, in the select a device, it will give priority to their size and power consumption.

Figure 1: functional block diagram for insulin pump system; Maxim provides the blue part of the solution.

To save space, the system designers need highly integrated programmes and a very small package, such as: chip scale package (such as us-letter UCSP package) and wafer level packaging (WLP).

In order to make the battery size as small as possible, the designers need to minimize energy consumption and increase efficiency. If possible, turn off those at any given time without the use of the circuit, then to the power supply.

The system's core is a highly integrated low standby power consumption microcontrollers — such as us-letter MAXQ2010, or other similar micro-controller manufacturer.

16-bit microcontrollers MAXQ2010, when working in 1MHz and 2.7V, power consumption of only 1mA, stop mode power consumption of only 370nA. This low-power characteristics on the extension of the insulin pump work life inside the battery is crucial. As with most micro-controller, USART, MAX2010 including timer, 64kB Flash-based program memory, some common i/o 2kBRAM, lead, with a reference voltage of 312.5k sample/sec 12-bit successive approximation ADC, 160 segment LCD controller and other resources. It can also be quickly from sleep and wake up, stop mode so that insulin pump can provide better, faster service user needs.

Figure 2: typical battery-insulin pump.