Catheter Reuse Limiter

ASIC Success Story

Application

UTIs caused by using a catheter are one of the most common types of infection that affect people staying in hospital. This risk is particularly high if your catheter is left in place continuously (i.e., an indwelling catheter). 

 CSS partnered with a leading supplier of catheters to create a system that limits the re-use of medical catheters and drives down the risk of UTI from extended catheter use.

Medical doctor holding health icon.
Layout image of catheter reuse limiter chip.

Custom Solution from CSS

This ASIC provides an ultra-low power timer that is configured to disable the catheter when certain conditions have been met. The timer section of the IC is powered by the high-voltage, treatment-mode RF signal. 

An off-chip capacitor provides several hours of operation after the RF power is removed. Four independent timers monitor several system conditions and determine when the catheter should be disabled. Each timer can be reconfigured via EEPROM, allowing great flexibility in defining the requirements to disable the catheter. Once disabled, an off-chip high voltage FET shorts out the coil. 

The RF generator detects the short and inhibits further treatment cycles. The circuit that drives the gate of the high voltage FET is powered by the Measure Mode RF signal, so there is no time limit on the disable function.

Key Features

  • Low Voltage – Supply voltage = 1.30V
  • Low Power – Active current ~ 50nA
  • Power is harvested from the 200V, RF treatment signal
  • ~5 hours of operation is provided by an off-chip 100uF capacitor
  • 30nA relaxation oscillator provides real-time clock with  ±5% accuracy
  • 4 Independent programmable counters
  • Internal Nonvolatile Memory (EEPROM)
  • Differential cell draws no static current
  • Stores catheter status & timer settings
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