Current-Mode Self-Sensing Temperature Sensor Using DC-CCII for Optoelectronic Devices

In this paper, a digitally controlled second-generation current conveyor (DC-CCII) and a transimpedance amplifier (TIA) will be employed to implement CMOS temperature sensor interface. The light emitting diode (LED) is used in optogenetic devices for optical stimulation. One of the major concerns of these devices is overheating that can cause cell damage. This work will utilize the LED used for optical stimulation as its own temperature sensor, in order to overcome the overheating concerns in optogenetics. LED reverses current represent temperature-sensitive parameter (TSP) and it can be used to sense the junction temperature. Therefore, the junction temperature can be used to measure the surface temperature. To ensure stable LED biasing and measure the LED reverse current, the CCII circuit will be utilized. In addition, the CMOS temperature sensor interface is operating under a ±0.75 V voltage supply. The standby power consumption of the circuit ranges between 240 μW at a gain for the DC-CCII equals to 0 dB and 700 μW at a gain for the DC-CCII equals to 16.9 dB. The proposed sensor interface has been implemented using LTspice with 0.25-μm CMOS technology.