A Current-Mode Floating-Bridge Technique for Closed-Loop ΣΔ Readout of Wheatstone Bridge Sensors
- Resource Type
- Conference
- Authors
- Raman, J.; Rombouts, P.
- Source
- 2019 IEEE International Symposium on Circuits and Systems (ISCAS) Circuits and Systems (ISCAS), 2019 IEEE International Symposium on. :1-5 May, 2019
- Subject
- Bioengineering
Components, Circuits, Devices and Systems
Power, Energy and Industry Applications
Signal Processing and Analysis
Bridge circuits
Sensors
Capacitors
Bridges
Modulation
Circuit noise
Transistors
- Language
- ISSN
- 2158-1525
We present a closed loop architecture for readout of Wheatstone bridge sensors. A key enabler of the proposed architecture is the floating bridge biasing technique. Thanks to this, the bridge's sense nodes can easily be read out in current mode. This current mode read-out in turn makes it very easy to convert the read-out front end amplifier of the bridge into an integrator. This integrator can then conveniently be used as the first integrator in a ΣΔ modulation feedback loop that can be set up around the sensor. This way we end up with a closed loop feedback system which has inherent A/D-conversion. We studied several design concerns in this system and explained how they could be overcome. Transistor level simulations confirm that the system can achieve adequate performance.