Implementation of a Double-Path Flipped Voltage Follower Cell for Voltage Conveyors

This paper presents a low-power class-AB second-generation voltage conveyor (VCII) based on a new high-drive flipped voltage follower (FVF) circuit. The proposed FVF cell establishes an additional negative feedback loop to enhance the driving capability of the VCII. This improvement ensures a very low output impedance and guarantees the accuracy of the circuit. Since the VCII is configured using two of the proposed FVF cells, it benefits from a simple structure, very low impedance at Y and Z terminals, high impedance at X terminal, and high accuracy in current and voltage conveying. In addition, the driving capability of the VCII is several tens of times larger than its biasing current. The circuit was fabricated using TSMC
$0.18~\mu $
m CMOS technology occupying a silicon area of
$121.5~\mu $
m
$\times 123.3~\mu $
m. Experimental results at a supply voltage of ±0.9 V show bandwidths of 155 MHz and 55.3 MHz for voltage and current transfer functions, respectively, while a static power of
$342~\mu $
W is consumed. The impedances at Y, Z and X terminals were measured by
$0.2\Omega $
,
$0.3\Omega $
, and 146 k
$\Omega $
, respectively.