Compared to voltage mode circuits, current mode circuits have advantages such as large dynamic range, fast speed, wide frequency band, and good linearity. In recent years, the development of call flow modeling technology has been rapid and has become an important foundation for analog integrated circuits. In this paper, a current mode chaotic oscillation circuit based on current differential transconductance amplifier (CDTA) is proposed. This proposed circuit fully utilizes the advantages of current differential transconductance amplifier: a current input and output device with a large dynamic range, virtual ground at the input, extremely low input impedance, and high output impedance. The linear and non-linear parts of the proposed circuit operate in current mode, enabling a true current mode multi scroll chaotic circuit. Pspice simulation results show that the current mode chaotic circuit proposed can generate multi scroll chaotic attractors.

https://www.frontiersin.org/articles/10.3389/fphy.2023.1202398/pdf

Current mode multi scroll chaotic oscillator based on CDTA

The design of low power and low voltage analog circuits is truly challenging. Therefore different approaches have been proposed and successfully employed. In this paper some of the low voltage topologies like Bulk Driven, Self-Cascode and DTMOS have been presented, and issues related to design are discussed briefly. These topologies are also used to design second generation current conveyors (CCII) and voltage mplifiers. The CCII is an important building block of a current feedback circuit like a current feedback operational amplifier (CFOA). Low voltage and low power are needed when those circuits are employed in the biomedical application and portable equipment. The designs are implemented using 0.18 µm CMOS technology.

Study of Low Power Techniques in Analog Circuit and Its Application to Design Second Generation Current Conveyors and Voltage Amplifiers

Abstract This study presents a high common-mode rejection ratio (CMRR), and high power-supply rejection ratio (PSRR) current-mode instrumentation amplifier (CMIA) to overcome the limitations of existing differential voltage second-generation current conveyors (DVCCII)-based CMIAs in achieving high CMRR. The design is based on a fully differential second-generation current conveyor block with a novel circuit design following by a current subtracting stage. The CMIA is designed and laid out in 130 nm CMOS technology operating under ± 1.2 V supply voltage in Cadence software. The post-layout simulation results show that the CMIA achieves low-frequency voltage and current CMRR- BW of 228.8 dB–10 kHz and 246 dB–10.6 kHz, respectively, with PSRR + /PSRR- of 108.2 dB/99.7 dB, power consumption of 507 µW, and a core area of 0.0015 mm 2 . The unique quality of the circuit is that, it does not need well-matched active blocks, but inherently improves CMRR, bandwidth, and PSRR; hence it gains an excellent choice for integration. 

/pdf/a-current-mode-instrumentation-amplifier-with-high-common-2gic4gss.pdf

A current mode instrumentation amplifier with high common-mode rejection ratio designed using a novel fully differential second-generation current conveyor

Thick electrodes with condensed active materials have been employed to increase volumetric and gravimetric capacity/energy density of lithium ion batteries (LIBs) for electric vehicle (EV) applications. However, thick electrodes suffer from low ionic transportation at high current rates during charging process. Introduction of channels along the thickness of the electrode to make 3-dimensional (3D) architectures leads to better performance under fast charging conditions when compared to baseline electrodes without channels. This can be attributed to the fact that the main factor limiting capacity density at high rates of charging is the diffusion of lithium ions across the cell. 3D channel architectures facilitates a large pathway for ionic transportation that leads to an overall reduction in cell internal impedance, electrode tortuosity and increased active surface area, resulting in better electrochemical and cycling performance. In this paper, a laser patterning process was employed to create channels (in the z-direction) along the thickness of a 74 µm thick electrode made of Philips graphite with 26% porosity. The rate performance test results demonstrated an improvement of 47.6%/49.3% in gravimetric capacity density at extremely fast charging rates of 4C/6C when compared to the baseline electrode. The cycling performance test under 3C showed more than 3 times improvement in capacity retention after 200 cycles for the laser patterned electrode compared to the baseline electrode, indicating the superior performance of the laser-patterned electrodes.

3D Architectures of a Thick Graphite Anode Enabled by Laser Patterning Process to Improve Capacity Density and Cycling Performance of LIBs

Fast charging capability has become one of the key features of lithium-ion batteries (LIBs) to facilitate the rapid growth of the electric vehicle (EV) market. However, charging thick electrodes in conventional EV batteries at high current densities always leads to adverse battery performance and safety issues. To address these challenges, thick graphite electrodes with patterned porous architecture were developed through a facile printing process. With selected graphite and developed formula, an appropriate graphite ink was printed onto the copper foil through the screen printing with designed patterned pore channels. The porous structure including pore diameter and pore-to-pore distance was controlled via adjusting the designed patterns on the screens. The presence of porous structure was confirmed through microscopic images. The printed graphite electrodes exhibited superior electrochemical behaviors over traditional electrodes in terms of rate capability and cycle life. It is believed that the improved battery performance is associated with the improved Li-ion transport arising from the patterned porous structure in printed electrodes. Results from the electrochemical impedance spectroscopy (EIS) indicate that, compared with traditional electrodes without patterned pores, printed electrodes have significantly reduced tortuosity. The post-mortem analysis of cycled cells demonstrates that the printed electrodes have the capability to suppress the Li plating related to fast charging rates. Combining with the advantages of low cost and high throughput, the printed electrode with patterned pores, thus, has the potential of replacing conventional electrodes in commercial LIBs to realize the fast-charging application.
 
 Keywords: Graphite, Printing, Fast charging, Li-Ion Batteries

Printed Graphite Electrodes for Fast Charging Lithium-Ion Batteries

Several printing techniques have been developed so far to fabricate advanced electrode structures with different 3D patterns for lithium ion batteries (LIB) applications. Making channels along the thickness of the electrode has been proved to be effective on energy density enhancement of LIBs by reducing the overall tortuosity in the electrode and improving the ionic diffusion along the electrode thickness, especially under fast charging conditions. In this paper, a 3D physics-based electrochemical model of Graphite/NMC (nickel, manganese, and cobalt) full-cell is developed in COMSOL software. The designed electrodes have cylindrical channels in both anode and cathode. The impact of channels on volumetric energy density of electrodes with different thickness and porosity under high current rate of 6 is investigated. The simulation results demonstrated that compared to reference cell with no channels, the patterned cell with similar mass loading is capable of increasing volumetric energy density by more than 2 times. The impact of electrode properties such as porosity, thickness, and cathode to anode thickness ratio is investigated and showed that the channels are more effective on improving energy density of thick electrodes with low porosities when compared to thin or highly porous electrodes with similar mass loading.

Investigating the Impact of Thickness and Porosity on Energy Density of Screen Printed Graphite/NMC LIBs with 3D Structures under Fast Charging Condition

A flexible anode was developed with graphite as active material for improving the rate capability of lithium-ion batteries (LIB) by targeting the choice of secondary solvents that are immiscible with primary solvents (aqueous). The ink consists of graphite as active material along with C-45 carbon black as conductive additive and carboxymethyl cellulose (CMC) as aqueous binder along with styrene-butadiene rubber (SBR). Octanol was chosen as secondary solvent as it is immiscible in water (primary solvent). Half-cell LIBs were assembled with graphite electrodes with 1 vol% octanol (Oct-1) and control electrode with 0 vol% octanol (Oct-0). Rate performance and capacity retention tests at different current rates were performed for Oct-1 and Oct-0 graphite electrodes. Oct-1 graphite electrodes delivered an enhanced specific capacity of 145 mAh/g when compared to Oct-0 graphite electrode with specific capacity of 115 mAh/g at current rate of 4C.

S. Ahmadi

Papers

A current mode instrumentation amplifier with high common-mode rejection ratio designed using a novel fully differential second-generation current conveyor

3D Architectures of a Thick Graphite Anode Enabled by Laser Patterning Process to Improve Capacity Density and Cycling Performance of LIBs

Printed Graphite Electrodes for Fast Charging Lithium-Ion Batteries

Investigating the Impact of Thickness and Porosity on Energy Density of Screen Printed Graphite/NMC LIBs with 3D Structures under Fast Charging Condition

Capillary Suspension Based Ink Formulation for Stable Graphite Anode in Lithium-Ion Batteries