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.