Powering wireless medical instrumentation requires the right approach: Page 4 of 4

January 30, 2017 // By Tony Armstrong
Powering wireless medical instrumentation requires the right approach
As with many applications, low power precision components have enabled rapid growth of portable and wireless medical instruments. However, unlike many other applications, many medical products typically have much higher standards for reliability, run-time and robustness. As you would expect, much of this burden falls on the power system and its associated support components.

The LT8602’s switching frequency can be programmed from 250kHz to 2MHz and can be synchronized throughout this range. Its 60ns minimum on-time enables 16VIN to 2.0VOUT step-down conversions on the high voltage channels with a 2MHz switching frequency. As the high voltage VOUT2 channel feeds the two low voltage channels (VOUT3 and VOUT4), these can deliver outputs as low as 0.8V while also switching at 2MHz, offering a very compact (~25mm x 25mm single sided) quad output solution as shown in Figure 3.

Fig. 3: LT8602 quad output solution footprint.

In addition the minimizing the solution footprint, the LT8602’s 2MHz switching frequency enables designers to avoid critical noise-sensitive frequency bands.  Each channel of the LT8602 maintains a minimum dropout voltage of only 200mV (at 1A) under all conditions, enabling it to excel in scenarios such as automotive cold-crank. Programmable power-on reset and power good indicators for each channel helps to ensure overall system reliability. The LT8602’s 40-lead thermally enhanced 6x6mm QFN package and high switching frequency keeps external inductors and capacitors small, providing a compact, thermally efficient footprint. In addition, unique design techniques and a new high speed process enable high efficiency over a wide input voltage range and the LT8602’s current-mode topology enables fast transient response and excellent loop stability.

 

Conclusion

It is clear that a system architect of wireless medical instrumentation faces many technical hurdles when designing a medical system for in-home patient care. The issue of potential noise interference must be mitigated, a battery backup operational capability in case the main power source fails and the size and cost have to be kept under control. Fortunately, there are plenty of appropriate solutions available from Linear to meet these design requirements.

 

 

About the author:

Tony Armstrong is Director of Product Marketing for Power Products at Linear Technology Corporation – www.linear.com

Design category: 

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