A 0.5V, 6.2μW, 0.059mm² Sinusoidal Current Generator IC with 0.088% THD for Bio-Impedance Sensing

Abstract

This paper presents the first sub-10µW, sub-0.1% total harmonic distortion (THD) sinusoidal current generator (CG) integrated circuit (IC) that is capable of 20kHz output for the bio-impedance (Bio-Z) sensing applications. To benefit from the ultra-low-power nature of near-threshold operation, a 9b pseudo-sine lookup table (LUT) is 3b ∆Σ modulated in the digital domain, thus linearity burden of the digital-toanalog converter (DAC) is avoided and only a 1.29µW of logic power is consumed, from a 0.5V supply and a 2.56MHz clock frequency. A half-period (HP) reset is introduced in the capacitive DAC, leading to around 30dB reduction of in-band noise by avoiding the sampling of data-dependent glitches and attenuating the kT /C noise and the non-idealities of reset switches (SW).

Continuous-Time Analog Filters for Audio Edge Intelligence: Review and Analysis on Design Techniques

“…16 shows a schematic, g m C equivalent, and block diagram of the flipped voltage follower (FVF)-based filter circuits [46]. The FVF circuit has been actively used as a core building block in various analog circuits to name, such as LPF [45], low-dropout (LDO) regulator [47]- [49], bio-signal amplifier [50]- [55], and current driver [56], [57]. As of the case in the SSF filters, the FVF filters are also categorized into two types according to the connection methods of C 1 capacitor.…”