A Fully Integrated Dynamic-Voltage-Scaling Stimulator IC with Miniaturized Reconfigurable Supply Modulator and Channel Drivers for Cochlear Implants

Cochlear implants (CIs) are biomedical devices that help treat severe hearing loss from inner-ear damage by delivering the audio signal captured by a microphone to auditory nerves through an electrode array (Fig. 1 (top)). Due to wide ranges of electrode-tissue interface (ETI) impedance and stimuli current magnitude, the stimulator in CIs often requires a high-voltage (HV) capability <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">( > 10V)</tex> and an efficient dynamic supply modulator (DSM) to achieve improved stimulation efficiency. Recently, stacked-switched-capacitor stimulation has been found to provide a high stimulation efficiency [1], but its slow charging time makes it unfit for CIs with narrow stimulation pulses within tens of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"></tex> [2]. Other conventional stimulators bear critical limitations including limited voltage range [1]–[3], low power efficiency [4], or large areas with bulky off-chip components [1], [2], [4]. <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">In</tex> this work, we present a fully integrated dynamic-voltage-scaling stimulator (DVSS) IC suited and scalable for high-channel-count CIs with a reconfigurable supply modulator (RSM) and HV-tolerant channel drivers, all implemented using low-voltage transistors.