Applications of Wireless Communication in a New Dual Branch CTS Charge Pump Based on Employing Clock Matched Technology

With the increase in communication requirements, new communication technologies and implementation methods have developed rapidly. The rise of emerging markets such as the Internet of Things, smart homes, smart cities, and wearables has promoted the development of wireless communication integrated circuits in the direction of monolithic, low energy consumption, and high energy efficiency. This paper proposes a new dual branch charge pump based on CTS charge pump with enhanced current drive capability and undesired charge transfer completely eliminated. Clock matched technology is proposed to completely eliminate undesired charge transfer caused by delay turn on and off of the auxiliary transistors in the traditional CTS charge pump. The current drive capability is enhanced by employing NMOS transistors with 2Vdd gate drive voltage, while traditional dual branch CTS charge pumps are based on PMOS with 1Vdd gate drive voltage. The output voltage ripple is also reduced resulting from a dual branch structure. Simulation results of output voltage gain and power efficiency for the proposed charge pump and other traditional charge pumps are provided. Comparisons are made to show the improvement of the proposed charge pump compared with other traditional charge pumps.

Folded Heterogeneous Silicon and Lithium Niobate Mach–Zehnder Modulators with Low Drive Voltage

Optical modulators were, are, and will continue to be the underpinning devices for optical transceivers at all levels of the optical networks. Recently, heterogeneously integrated silicon and lithium niobate (Si/LN) optical modulators have demonstrated attractive overall performance in terms of optical loss, drive voltage, and modulation bandwidth. However, due to the moderate Pockels coefficient of lithium niobate, the device length of the Si/LN modulator is still relatively long for low-drive-voltage operation. Here, we report a folded Si/LN Mach–Zehnder modulator consisting of meandering optical waveguides and meandering microwave transmission lines, whose device length is approximately two-fifths of the unfolded counterpart while maintaining the overall performance. The present devices feature a low half-wave voltage of 1.24 V, support data rates up to 128 gigabits per second, and show a device length of less than 9 mm.

Coulomb-actuated microbeams revisited: experimental and numerical modal decomposition of the saddle-node bifurcation

Electrostatic micromechanical actuators have numerous applications in science and technology. In many applications, they are operated in a narrow frequency range close to resonance and at a drive voltage of low variation. Recently, new applications, such as microelectromechanical systems (MEMS) microspeakers (µSpeakers), have emerged that require operation over a wide frequency and dynamic range. Simulating the dynamic performance under such circumstances is still highly cumbersome. State-of-the-art finite element analysis struggles with pull-in instability and does not deliver the necessary information about unstable equilibrium states accordingly. Convincing lumped-parameter models amenable to direct physical interpretation are missing. This inhibits the indispensable in-depth analysis of the dynamic stability of such systems. In this paper, we take a major step towards mending the situation. By combining the finite element method (FEM) with an arc-length solver, we obtain the full bifurcation diagram for electrostatic actuators based on prismatic Euler-Bernoulli beams. A subsequent modal analysis then shows that within very narrow error margins, it is exclusively the lowest Euler-Bernoulli eigenmode that dominates the beam physics over the entire relevant drive voltage range. An experiment directly recording the deflection profile of a MEMS microbeam is performed and confirms the numerical findings with astonishing precision. This enables modeling the system using a single spatial degree of freedom.

The trajectory of discrete gating charges in a voltage-gated potassium channel

Positively-charged amino acids respond to membrane potential changes to drive voltage sensor movement in voltage-gated ion channels, but determining the trajectory of voltage sensor gating charges has proven difficult. We optically tracked the movement of the two most extracellular charged residues (R1, R2) in the Shaker potassium channel voltage sensor using a fluorescent positively-charged bimane derivative (qBBr) that is strongly quenched by tryptophan. By individually mutating residues to tryptophan within the putative trajectory of gating charges, we observed that the charge pathway during activation is a rotation and a tilted translation that differs between R1 and R2 and is distinct from their deactivation pathway. Tryptophan-induced quenching of qBBr also indicates that a crucial residue of the hydrophobic plug is linked to the Cole-Moore shift through its interaction with R1. Finally, we show that this approach extends to additional voltage-sensing membrane proteins using the Ciona intestinalis voltage sensitive phosphatase (CiVSP).

Simultaneous realization of high-efficiency, low-drive voltage, and long lifetime TADF OLEDs by multifunctional hole-transporters

A smart high-triplet energy hole-transporter exhibits significant stability in the anion state realizing record-breaking highly efficient and long-living thermally activated delayed fluorescent (TADF) organic light-emitting devices (OLEDs).