Mirrored Current-Conveyor Transimpedance Amplifier for Home Monitoring LiDAR Sensors

Abstract

This article presents a current mode transimpedance amplifier (TIA) implemented in a standard 65-nm CMOS technology for the applications of elder-care home monitoring LiDAR sensors. Particularly, a novel mirrored current-conveyor (MCC) input configuration is proposed to lower the input impedance, thus achieving a wide bandwidth. This MCC-TIA can alleviate severe pulse spreading issue for near-range detection, enabling effective narrow-pulse recovery. Also, a feedforward control-voltage generator is newly suggested to realize an automatic gain-control within a single pulse-width duration. Measured results demonstrate the variable transimpedance gain of 59∼77 dB to accommodate the incoming input currents of 18 μA pp ∼ 2.24 mA pp that corresponds to the feasible detection range of 0.5∼5.3 meters in an elder's home. The bandwidth of 83 MHz∼2.6 GHz is measured with the minimum noise current spectral density of 16.8 pA/sqrt(Hz). The chip dissipates 40 mW in total, and occupies the area of 1.0 mm 2 , including I/O pads.

A Current-Mode Optoelectronic Receiver IC for Short-Range LiDAR Sensors in 180 nm CMOS

“…Figure 8 shows the block diagram of the voltage-mode optoelectronic receiver (V-OER) which consists of an APD as an optical detector, a VFIC as a TIA to convert the generated photocurrents to electrical voltages, a single-to-differential (S2D) converter for differential signaling, a differential gain stage for gain boosting, and a cross-coupled inverter post-amplifier (CI-PA) for offset cancellation. An output buffer (OB) is inserted not only for 50 Ω impedance matching, but also for the effective isolation of the V-OER circuit from the following time-to-digital converter (TDC) that is typically employed to estimate the time interval between the transmitted pulses and the received echo pulses [9,10].…”

An Indoor-Monitoring LiDAR Sensor for Patients with Alzheimer Disease Residing in Long-Term Care Facilities

“…Early fall detection is an essential aspect of providing the necessary medical response in a timely manner to older patients with Alzheimer disease or senile dementia residing in long-term care facilities (LTCFs) or homes [ 1 , 2 , 3 ]. With the advancement of sensing and signal processing technologies, various fall detection methods have been proposed.…”

A CMOS Integrator-Based Clock-Free Time-to-Digital Converter for Home-Monitoring LiDAR Sensors

“…Recently, light detection and ranging (LiDAR) sensors have been exploited in various time-of-flight (ToF) applications, including unmanned autonomous vehicles that can drive safely by recognizing the surrounding environment with real-time three-dimensional (3D) mapping, e.g., Google self-driving cars with panoramic scan sensors [1]; home-monitoring LiDAR sensors for either single elders living alone or senile dementia patients residing in nursing homes [2,3]; and remote sensing LiDAR sensors for the purpose of observation of forestry, the cryosphere, aerosols, and clouds.…”

“…In particular, home-monitoring LiDAR sensors have become urgently needed to help professional nurses take care of their dementia patients more efficiently. It is well known that many developed countries have been facing the surge of senior citizen populations due to their advanced health systems [2], which naturally leads to the proliferation of senile dementia patients. In South Korea, the Ministry of Health-Welfare predicted that 10% of senior citizens, i.e., one million elders, might suffer dementia in 2025.…”