A new family of low-voltage circuits based on quasi-floating gate transistors

A very compact KHN filter with multidecade tuning

“…Consequently, the effective resistance can be tuned from hundreds of kilo-ohms to the range of Gigaohms, while a capacitor of a few picofarads is enough to obtain cutoff frequencies in the order of hertz. Three transistors are necessary to avoid direct polarization of the parasitic active-substrate diodes due to signal fluctuations between the terminals of R g , increasing the dynamic range [9,10]. In addition, the weak-inversion operation of transistors M p2 forces R g <<R B (where R B is the diffusion resistance), in order to avoid a parasitic resistive divider [11].…”

Comparison of Quasi-/Pseudo-Floating Gate Techniques and Low-Voltage Applications

“…The input circuit with a single QIR, as shown in Fig. 3(b), is the simplest connection, and with a GD-QIR structure, was used in [16]. Connecting the substrate diode in such a single-QIR structure to bias voltage V B eliminates dc offset.…”

“…Recently, several authors have presented techniques using so-called quasi-or pseudo-floating gates (QFGs) as a way to deal with the initial-charge problem [14][15][16][17][18]. A QFG transistor is implemented by providing a weak electric connection between a QFG node and a bias voltage source using a very large or quasi-infinite resistor (QIR).…”

“…Accoupling also allows optimizing common-mode voltage ranges to enhance voltage swings and dynamic range. So, as we will demonstrate, the QFG technique retains Several ways have been proposed to implement the required quasi-infinite resistors [14][15][16][17][18]. However, the strengths and weaknesses of these structures for different applications have not been systematically compared.…”

Low-Voltage MOS Translinear Analog Signal Processing

“…At a device level, the exploitation of MOS operating regions scarcely employed in the past, such as weak or moderate inversion, has been investigated (e.g., [3]). Different ways of driving MOS transistors have been devised, directly to the body terminal [6] or by capacitive coupling to a floating [7,8] or quasi-floating [9,14] gate.…”