A Wireless IC for Time-Share Chemical and Electrical Neural Recording

A Wireless FSCV Monitoring IC With Analog Background Subtraction and UWB Telemetry

“…In an oversampling ΔΣ ADC, the undecimated unencoded data rate $R_b^{\prime }$ is given by $$R_b^{\prime }=\mathit{OSR}\times f_s.$$ In [9]–[11], the unencoded data rate of the transmitter is equal to the undecimated data rate of the ΔΣ modulator because the decimation filter is implemented on the receiver side due to its complexity, area and power. Comparing (11) and (12) with N = 9 and OSR = 32 reveals the ADC in this work yields a 3.5× reduction in the wireless data transmission rate compared to the ADC in [10]. Assuming a wireless link with power directly proportional to the data rate, such as in a duty-cycled IR-UWB TX, this reduction also yields a 3.5× decrease in transmit power, the main component of the power budget in low-power wireless sensing systems.…”

“…This increase in resolution compares favorably to that achieved through ΔΣ modulation, which roughly provides L +0.5 additional bits of resolution, where L is the modulator’s order, for each doubling of the oversampling ratio OSR . To achieve a dynamic range of N + M bits, where N + M is large, a single-bit ΔΣ modulator requires an OSR given by $$\mathit{OSR}={\left(2^{N+M}\frac{{\pi }^L}{\sqrt{2L+1}}\right)}^{\frac{1}{L+0.5}}.$$ Plugging N = 9 and M = 5 for the values used in this work and L = 3 for the third-order modulator in [10] into (10) yields an OSR of 32. This result indicates that even with the use of a high-order modulator, which increases design complexity and power consumption, a third-order ΔΣ ADC still requires 32× the sampling rate of the Nyquist ADC used in this work given the same dynamic range requirement.…”

Implantable CMOS Biomedical Devices

“…For example, in retinal prosthesis, retinal cell stimulation is often adaptively controlled by monitoring the impedance value. In addition, for deep brain stimulation, such an implanted device is proposed that monitors the amount of dopamine emitted in a patient's brain, determines the optimum value of stimulation, and stimulates the deep brain before the onset of tremor is currently being developed [10]. This is a typical example of a closed-loop device.…”

CMOS Neurotransmitter Microarray: 96-Channel Integrated Potentiostat With On-Die Microsensors

“…Measuring neurotransmitter concentration in vivo facilitates studies of various neurological disorders in order to identify new treatments but may be prohibitively slow and risky [1]. Imaging neurotransmitters in vitro, such as in cell cultures and brain slices, yields a fast and low-risk platform for early-stage high-throughput drug screening and drug discovery.…”