|Title||A wireless photostimulator for optogenetics with live animals|
|Publication Type||Conference Paper|
|Year of Publication||2017|
|Authors||Gagnon-Turcotte G., Maghsoudloo E., Messaddeq Y., De Koninck Y., Gosselin B.|
|Conference Name||2017 15th IEEE International New Circuits and Systems Conference (NEWCAS)|
|Keywords||Batteries, Charge pumps, CMOS, DC/DC converter, Light emitting diodes, Low-voltage, Optogenetics, Pulse width modulation, Threshold voltage, Voltage control, Wireless, Wireless communication, μLED driver|
In this paper, we present a wireless photostimulator providing high output power from small 1.5-V Zinc-Air coin battery to stimulate light sensitized neurons. To overcome the limits of such a small energy source e.g. discharging current and voltage, the proposed photostimulator is based on a DC/DC converter and a switched capacitor circuit to provide high voltage (4 V) and high current (maximum 20 mA) to the stimulating μLEDs. These LED driving voltages and currents are modulated by a PWM signal, and designed to provide a stimulation pulsewidth of 5-ms at a period of 500 ms. A charge pump circuit is used to boost the battery voltage level up to 4 V from the aforementioned low-voltage coin battery. The output current of the proposed LED driver circuit is adjustable to provide different output light power levels output. The post layout simulation results in IBM CMRF8SF 130-nm process shows a variation of less than 1 % of the output LED driver current of the across all PVT corners. The efficiency of the proposed photostimulator, including the charge pump and the LED driver, is of 66 %.