Ultrasonically Powered and Controlled Microsystem for Dual-Wavelength Optogenetics With a Multiload Regulation Scheme

This letter presents an ultrasonically powered dual-wavelength optogenetic device that targets simultaneous excitation and inhibition of neural activities, or in a broader sense, optical stimulation in two distinct wavelengths for targeting different populations of neurons. This can be applied to a variety of neurological disorders. The device features a load regulator circuit that shares the available power budget between two $\mu $ LEDs in a power-efficient and controlled way suppressing the need for adaptive matching and overvoltage protection circuits. Furthermore, the regulator circuit is capable of detecting power burst availability on the device and generating a control signal, accordingly. For $\mathbf {5.25}$ -mW acoustic power at the device’s surface, the rectified voltage, and the total current load of the system are regulated to 2.79 V and $600~\mu \text{A}$ , respectively. The maximum chip and device efficiencies of 92.5% and 31.8% are measured, respectively. The total die area in 180- $\mathbf {nm}$ CMOS technology nose and the estimated system volume are $0.16~\mathbf {mm^{2}}$ and $0.572~\mathbf {mm^{3}}$ , respectively.