Biosensor signal improvement using current mirror topology for dissolved oxygen measurement

• Published in: Measurement science & technology 2019-06, Vol.30 (6), p.65102
• Main Authors: Umar, Lazuardi, Hamzah, Yanuar, Setiadi, Rahmondia N
• Format: Article
• Language: English
• Subjects: biosensor; current mirror; dissolved oxygen; oxygen electrode; transimpedance amplifier
• ISSN: 0957-0233; 1361-6501
• DOI: 10.1088/1361-6501/ab0675

A biosensor system for dissolved oxygen level detection based on a current mirror method has been designed and characterized. Most biosensor systems implement a transimpedance circuit to convert the flowing current on the sensor to an output voltage signal. These systems are voracious and susceptible to instability and noise due to the configuration of the circuit used. The power supply is also impractical due to the bipolar polarity needed, and the systems consume more power since they use more active devices in the op-amp. These disadvantages need to be overcome when special requirements are needed such as low-noise measurement in dissolved oxygen level detection, and for battery-powered and low-power devices for in situ and remote area measurement. Differing from transimpedance, current mirror circuits convert the flowing current to the output voltage by copying the current with a ground-referenced input and output, and use fewer active devices. The proposed current mirror circuit aims to diminish the noise of the output and minimize the power consumption through reducing the active devices used. The results show some significant signal quality improvements when using the current mirror circuit, where the noise response of the current mirror circuit is ten times lower than the transimpedance circuit.