A motion detection pixel system using an inductorless UWB transmitter on standard 0.35µm/CMOS technology

This paper presents a CMOS pixel motion detector based on a current-mode APS (Active Pixel Sensor) topology with wireless capability using an Impulse Radio - Ultra Wide Band (IR-UWB) in standard 0.35μm CMOS technology for applications in image sensor networks. A pixel was designed with a transmission gate to control one copier cell in order to compare different integration times. The pixel output is a digital signal proportional to the difference between the two currents. The proposed IR-UWB has a simple architecture, without inductors and carrier modulators. It is based on parallel pulse generator blocks that produce Gaussian pulses, and a pulse shaping stage which adjusts the pulse amplitude, below the FCC -41.3dBm floor. The transmitter exhibits as main characteristics: output pulse of 408ps wide at 4.90GHz, and voltage amplitude of 144mVpp, an average power is only of 7.15μW/pulse at 170MHz PRF (Pulse Repetition Frequency). The whole circuit has been simulated using LTSpice and the results demonstrate the circuit capability to operate as a motion detector. The complete circuit pixel occupies a very small area of 120μm × 115μm.