Crosstalk Voltage Research Articles

Improved Design of a SiC MOSFET Gate Drive with Crosstalk Suppression Capability

For high-frequency switching applications, silicon carbide (SiC) devices are more suitable than silicon-based devices, which is conducive to improving the efficiency and power density of power electronic equipment. However, as the switching frequency increases, the influence of parasitic parameters on the switching characteristics of devices becomes increasingly apparent. When SiC metal-oxide-semiconductor field-effect transistors (MOSFETs) are applied in bridge circuits, the crosstalk problem easily occurs with the complementary conduction of upper and lower transistors, which seriously limits the promotion of SiC MOSFETs. However, the existing crosstalk suppression drive circuit tends to increase the switching loss, switching delay, and control complexity; therefore, a gate drive with crosstalk suppression capability is proposed. In this paper, the gate drive has two features: a negative voltage to shut down the SiC MOSFET; and an adjustment of the gate-source equivalent impedance. To accomplish this goal, the mechanism of crosstalk voltage generation is analyzed. Furthermore, the operation principle of the gate drive is analyzed, and the parameters of the gate drive are designed. Eventually, the proposed gate drive is verified by an LTspice simulation and experimental platform. The results prove that the gate drive can suppress the crosstalk voltage without affecting the switching speed.

A Novel 4H-SiC Asymmetric MOSFET with Step Trench.

In this article, a silicon carbide (SiC) asymmetric MOSFET with a step trench (AST-MOS) is proposed and investigated. The AST-MOS features a step trench with an extra electron current path on one side, thereby increasing the channel density of the device. A thick oxide layer is also employed at the bottom of the step trench, which is used as a new voltage-withstanding region. Furthermore, the ratio of the gate-to-drain capacitance (Cgd) to the gate-to-source capacitance (Cgs) is significantly reduced in the AST-MOS. As a result, the AST-MOS compared with the double-trench MOSFET (DT-MOS) and deep double-trench MOSFET (DDT-MOS), is demonstrated to have an increase of 200 V and 50 V in the breakdown voltage (BV), decreases of 21.8% and 10% in the specific on-resistance (Ron,sp), a reduction of about 1 V in the induced crosstalk voltage, and lower switching loss. Additionally, the trade-off between the resistance of the JFET region (RJFET) and the electric field in the gate oxide (Eox) is studied for a step trench and a deep trench. The improved performances suggest that a step trench is a competitive option in advanced device design.

A novel driver circuit of SiC MOSFET for suppressing crosstalk voltage in bridge circuit

Due to the presence of crosstalk voltage in the circuit, SiC MOSFET devices can be damaged or misled. Suppressing crosstalk voltage makes it an important step for the circuit to function properly. This article first delves into the causes of crosstalk voltage generation. The main research object is synchronous Buck converters, and the reasons for the crosstalk voltage of SiC MOSFETs are analyzed. Afterwards, a novel drive circuit was designed to suppress crosstalk voltage, and the working principle of this drive circuit was analyzed. Finally, simulation was conducted using LTspice software to study and analyze the simulation results, proving the feasibility of this novel drive circuit for suppressing crosstalk voltage, and demonstrating the advantages and disadvantages of this novel drive circuit for suppressing crosstalk voltage.

Reliable Gate Driving of SiC MOSFETs With Crosstalk Voltage Elimination and Two-Step Short-Circuit Protection

The over-stress of the negative gate-source voltage of SiC MOSFET, even in a short period of time, could cause the threshold voltage drift of the device, resulting in increased on-state resistance. In this paper, we propose an integrated gate driver to specially limit the peak negative gate voltage of SiC MOSFETs introduced by the crosstalk phenomenon and the reliable short-circuit protection. A simple auxiliary branch with bidirectional blocking capability is adopted in crosstalk voltage suppression and the negative peak voltage of the gate, introduced by common source inductor, is eliminated by the high impedance gate driving loop. Furthermore, the auxiliary circuit is re-used to assist a two-step short-circuit protection of the device by identifying dc-link shoot-through current on the stray inductor. By rapidly reducing the gate-source voltage to a lower value when short-circuit happens, the short circuit withstanding time of the device is prolonged, enabling a longer allowable detection time to confirm the fault event accurately. The proposed method comprehensively integrates the crosstalk voltage suppression and short circuit protection together and is verified by the experiments.

Analytical models of the crosstalk voltage in SiC MOSFETs under different loads

AbstractDue to the higher switching speed and lower threshold voltage of SiC MOSFET, its crosstalk issue is more serious than that of Si devices. Firstly, the mechanism and process of crosstalk under resistive load and inductive load are compared and analyzed. Then, a parameter decoupling method based on energy conservation is proposed, and an analytical model of the crosstalk voltage under resistive load is established. Moreover, an analytical model of the crosstalk voltage under inductive load with only device and circuit parameters is introduced. Furthermore, the influence of the drive resistance and the common source inductance on the crosstalk voltage under different loads is evaluated through the analytical model. Finally, a double pulse test is carried out to verify the validity of the analysis. The results presented here can provide guidance for the design of gate circuit parameters to regulate the crosstalk issue of SiC MOSFETs under different loads.

Long-duration bipolar linear transformer driver based on a multi-turn half-bridge structure

All-solid linear transformer driver(LTD) generators are widely used to output unipolar high-voltage rectangular pulses in nanoseconds. However in some applications, the bipolar output is necessary and the size of the generator is limited, which is challenging for LTD topology because the size of the magnetic core is related directly to the amplitude and pulse duration of the output waveforms. In this paper, a bipolar long-duration pulse generator based on the topology of a linear transformer driver combined with a half-bridge and multi-turn structure is put forward. The half-bridge topology can output bipolar waveforms easily and can save the number of switches used in the generator. To eliminate the crosstalk voltage that appears during operation, a differential mode inductance is used to protect the circuit. A snubber circuit is applied to suppress the reverse overshoot. The multi-turn design is chosen to make the size more compact. However, the multi-turn usually leads to a lower rise speed. To improve the performance, an optimization method that improves the rising speed by changing the turns of each stage is discussed. The strategy is useful and can be applied on some other occasions. The generator can output bipolar waveforms whose amplitudes are 4 kV and the duration can be adjusted from 200 ns to 800 ns. The rise time can be limited to 70 ns. The size of the generator is 10 cm * 10 cm * 15 cm, which is compact compared to the generators put forward before.

Analysis for crosstalk of SiC-MOSFET in a bridge circuit and its active-clamped driver based suppression methods

Because of the benefits of lower on-state resistance, higher operating voltage, and higher switching frequency, SiC-MOSFET has gradually become an ideal choice for the development of power converters operating in high voltage, temperature, and power density. However, the greater dv/dt and di/dt during fast switching transients in the bridge circuit may produce substantial crosstalk problems on the complementary device due to parasitic characteristics of the device itself and its package, and with the lower turn-on threshold voltage and reverse voltage withstand capability, the crosstalk voltage will directly threaten its safe operation. This paper presents the association between the crosstalk voltage and the parameters in driving circuit and device according to the theoretical analysis of the crosstalk mechanism in a half-bridge circuit and based on the analysis, a gate driver circuit using auxiliary low-power Si-MOSFET are proposed to suppress the crosstalk spike without additional negative gate–source voltage or control signal and can be implemented with low cost and less complexity. The operation principle and parameter design of the key components are analyzed later. Finally, the simulation and experiment results show that proposed active clamped gate driver is effective at suppressing crosstalk.

Study on the Electromagnetic Interference of Shielded Cable in Rail Weighbridge

In view of the electromagnetic interference (EMI) of the signal shielded cable in the rail weighbridge, the interference source is analyzed on the basis of the field measurement and investigation, and methods of suppressing the crosstalk voltage of the shielded cable are proposed. First, the capacitive coupling model between the power line and the shielded cable is established, and the coupling model between the shielded layer and the core is developed. Later, the distribution parameters of the multi-conductor transmission line system are extracted by the commercial software ANSYS based on the finite element method. Then the coupling voltages of the shielded layer and the core can be calculated; compared with the measured results, the accuracy and effectiveness of the proposed method are verified. Finally, the EMI suppression methods are proposed and its effectiveness is verified. The EMI of the shielded cable is very common in engineering, and this method has a good reference value for solving the similar problems.

Machined phononic crystals to block high-order Lamb waves and crosstalk in through-metal ultrasonic communication systems

For systems that require complete metallic enclosures (e.g., containment buildings for nuclear reactors), it is impossible to access interior sensors and equipment using standard electromagnetic techniques. A viable way to communicate and supply power through metallic barriers is the use of elastic waves and ultrasonic transducers, introducing several design challenges that must be addressed. Specifically, the use of multiple communication channels on the same enclosure introduces an additional mechanism for signal crosstalk between channels: guided waves propagating in the barrier between channels. This work numerically and experimentally investigates a machined phononic crystal to block MHz Lamb wave propagation between ultrasonic communication channels, greatly reducing wave propagation and the resulting crosstalk voltage. Blind grooves are machined into one or both sides of a metallic barrier to introduce a periodic unit cell, greatly altering the guided wave dispersion in the barrier. Numerical simulations are used to determine a set of groove geometries for testing, and experiments were performed to characterize the wave-blocking performance of each design. The best-performing design was tested using piezoelectric transducers bonded to the barrier, showing a 14.4 dB reduction in crosstalk voltage. The proposed periodic grooving method is a promising technique for completely isolating ultrasonic power/data transfer systems operating in a narrow frequency range.

Modeling and Suppression of the Crosstalk Issue Considering the Influence of the Parasitic Parameters of SiC MOSFETs

Due to the extremely fast switching speed of the SiC MOSFET, its crosstalk issue is more serious than that of the Si IGBT. Therefore, in order to ensure the reliability of the SiC MOSFET converters, the crosstalk problem must be solved firstly. Most of the existing crosstalk suppression methods are aimed at decreasing the crosstalk voltage introduced by the parasitic gate-drain capacitance (Miller capacitance), ignoring the influence of other parasitic parameters on the crosstalk voltage, such as the common source inductance, which may also lead to more serious reliability problems. Thus, this paper firstly establishes the mathematical model of the switching process of the SiC MOSFET half-bridge inverter. Then, the effects of various parasitic parameters (the gate-source capacitance, the gate-drain capacitance, the common source inductance, the gate inductance, the drain inductance) on the crosstalk voltage are analyzed and modeled in detail, which is verified by experiments. Based on the analyses and models, a novel crosstalk voltage suppression circuit is proposed, which can not only suppress the crosstalk caused by the gate-drain capacitance, but also solve the crosstalk issue considering the influence of other parasitic parameters, such as the common source inductance. Finally, a double pulse test platform is established to verify the effectiveness of the designed crosstalk suppression circuit under different voltage/current conditions.

Characterization and optimization of gate driver turn-off voltage for eGaN HEMTs in a phase-leg configuration

Affected by high switching speed and parasitic parameters, crosstalk problem of eGaN HEMT in a phase-leg configuration cannot be ignored. By decreasing gate driver turn-off voltage, the false turn-on phenomenon of device caused by crosstalk can be avoided, but it is hard to realize the minimization of total power loss. Thus, we analyze the influence of gate driver turn-off voltage on eGaN HEMT reverse conduction loss, switching loss and crosstalk voltage, and propose an optimized design rules for determining turn-off voltage value in a phase-leg configuration. By reasonably choosing gate driver turn-off voltage, a balance between optimal loss and reliable operation is achieved, thereby effectively alleviating the conflict between efficiency and reliability in the power electronic system.

A Novel Method for Predicting Crosstalk in Lossy Twisted Pair Cable Based on Beetle Antennae Search and Implicit Wendroff FDTD Algorithm

ABSTRACT This paper presents an algorithm for predicting crosstalk in multiconductor transmission lines (MTL). Currently, crosstalk has an increasing impact on signal integrity. In the twisted pair cable (TPC), different rotation degrees correspond to different RLCG parameter matrices, these matrices are predicted by the beetle antennae search-back propagation neural network (BAS-BPNN) algorithm, and use implicit wendroff-finite difference time domain (IWFDTD) method to solve near-end and far-end crosstalk voltages. The CST simulation results show that near end and far end crosstalk can be predicted effectively. This proposed method is expected widely used in electronic applications for fast data transfer.

A Multi-Level Gate Driver for Crosstalk Suppression of Silicon Carbide MOSFETs in Bridge Arm

In high frequency applications of silicon carbide (SiC) MOSFET, it is easy to be affected by parasitic parameters where crosstalk phenomenon in bridge arm will occur. This paper proposes a novel multi-level gate driver which can suppress the crosstalk phenomenon of the SiC MOSFETs in bridge arm. An auxiliary MOSFET branch between the gate and source of SiC MOSFET is adopted to generate negative and zero gate voltage when SiC MOSFET is turned off. The negative gate voltage may reduce the positive gate crosstalk voltage, and zero gate voltage may reduce negative gate crosstalk voltage. Both the simulations and experiments are carried out to verify the feasibility and high performance of the proposed multi-level gate driver. Compared to the conventional gate driver, the proposed multi-level gate driver reduces the positive crosstalk voltage to -2.2V, and the negative crosstalk voltage to -4.4V, respectively.

Analysis and Suppression of High Speed Dv/Dt Induced False Turn-on in GaN HEMT Phase-Leg Topology

Gallium nitride high electron mobility transistor (GaN HEMT) is liable to gate false turn-on problem when the gate crosstalk voltage exceeds its threshold voltage in the widely adopted phase-leg topology due to its low threshold voltage and high switching speed. Without considering the gate loop stray inductance, gate internal resistance, nonlinearity of parasitic capacitances and power loop stray parameters, traditional false turn-on analytical method is insufficient to support accurate analysis. And it has been found that GaN HEMT gate-source parasitic capacitance C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">gs</sub> previously assumed constant is otherwise highly nonlinear and has strong impacts on the gate crosstalk voltage. This paper has measured C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">gs</sub> by vector network analyzer and constructed an accurate nonlinear model of C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">gs</sub> , based on which an accurate GaN HEMT behavior model is further fulfilled. The accuracy of the proposed behavior model has been verified by large amounts of experiment results. The proposed GaN HEMT model is used to accurately calculate gate crosstalk voltage and switching losses. Besides, false turn-on induced extra loss has been calculated and is adopted as a criterion to evaluate the severity of false turn-on and optimal design method for false turn-on suppression has been detailed further.

The Preliminary Results of Crosstalk Analysis Under Vibration Stress

To assess the influence of vibration on the crosstalk between cables, the Finite Element Method is introduced to solve the cable displacement analysis under random vibration. Then the crosstalk model considering vibration is constructed by use of the Monte Carlo method. It is found that the superposition of vibration modes above three orders has little effect on the crosstalk analysis. Also, it is demonstrated that as the displacement induced by vibration increases, the distribution of crosstalk voltage becomes more dispersed, the worst-case crosstalk can occur.

Modeling and Analysis of Bridge-Leg Crosstalk of GaN HEMT Considering Nonlinear Junction Capacitances

Gallium nitride high electron mobility transistor (GaN HEMT) has fast switching speed and low threshold voltage, which could result in a severe false triggering voltage pulse at the synchronous freewheeling transistor in bridge-leg circuit when the control transistor turns on. To suppress the crosstalk phenomenon, this article proposes an analytical model about the crosstalk voltage, with consideration of nonlinearities in capacitance-voltage (C-V) of GaN HEMT. By utilizing the equivalent circuit of control transistor and synchronous freewheeling transistor, the number of analytical model parameters to be extracted can be reduced significantly. Besides, the nonlinear characteristic of junction capacitances is taken into account in the model, and the accuracy is verified by the current-voltage (I-V) curve of capacitances. Based on the model, an exhaustive investigation into the impact of device and circuit parameters on the crosstalk phenomenon is conducted. Further, for the purpose of evaluating the oscillation of crosstalk voltage, the damping ratio and oscillation frequency are acquired. The proposed model can be applied to guiding GaN device selection and printed circuit board (PCB) circuit design. The effectiveness and superiority of the proposed model are verified with simulations and experiments on a double pulse test platform.

An Improved Active Crosstalk Suppression Method for High-Speed SiC MOSFETs

Silicon carbide (SiC) power electronic devices feature the advantages of fast switching speed, low conduction loss, and reliable operation in high temperature environment, etc. Due to the differences of parasitic parameters and threshold voltage between SiC mosfet s and Si mosfet s, crosstalk problem is easy to be triggered when SiC mosfet s are applied to bridge topologies. In this paper, the crosstalk effect with different parasitic parameters of SiC mosfet s is firstly analyzed, and then an improved active crosstalk suppression method for high-speed SiC mosfet s is proposed. By using the proposed method, when the crosstalk occurs, the crosstalk voltage will be decreased by reducing the equivalent gate resistance and increasing the equivalent gate-source capacitance in an active way. Consequently, the crosstalk problem can be suppressed without affecting the switching speed. To verify the effectiveness of the proposed method, a prototype of a buck–boost converter is built and the proposed modified gate driver is applied to the half-bridge topology. Comparative experimental study is conducted and the crosstalk voltage is analyzed. The experimental results verify that effective crosstalk suppression is achieved.

High Off-State Impedance Gate Driver of SiC MOSFETs for Crosstalk Voltage Elimination Considering Common-Source Inductance

The crosstalk voltage on the gate-source terminal of SiC power mosfets in a phase-leg circuit is composed of the gate-drain capacitor introduced voltage and the common-source inductor introduced voltage. The mathematical model of the crosstalk voltage indicates that to suppress two types of crosstalk voltage, there exists a contradictory requirement on the off-state gate loop impedance. This challenge reduces the effectiveness of conventional crosstalk elimination methods. As an improvement, a crosstalk voltage suppression circuit that synchronously eliminates the crosstalk voltage of gate-drain capacitance and the common-source inductance is proposed. In this article, instead of creating low-impedance gate loop in the off-state, a high-impedance gate loop is formatted to eliminate the voltage drop on the common-source inductance. Meanwhile, the potential false turn-on or the negative voltage spikes caused by gate-drain capacitance is eliminated by the precharge voltage in the gate-source capacitor. The required prestored charge is analyzed considering the nonlinear behavior of the junction capacitance of the SiC mosfets. The proposed gate driver is experimentally verified in different switching conditions.

Noise and crosstalk models of the particle detector with zero-pole transformation charge sensitive amplifier

Abstract This paper presents design and mathematical noise model of front-end electronics for a silicon particle detector , considering the complete transfer function of a charge sensitive amplifier (CSA). The work includes the noise and crosstalk analysis of a pixel array with a conventional CSA and a zero-pole transformation CSA (ZPT–CSA) (Jaffari et al., 2011). The pixel array has been designed and simulated in a 180 nm CMOS technology with the supply voltage of 1.8 V and the substrate potential of –10 V. The comparative study for conventional and ZPT–CSA is performed with the circuit simulations. The study demonstrates a reduction of 30 % in output noise spectral density and 46 % in equivalent noise charge (ENC) for a frequency band of 100 kHz–100 MHz by using a zero-pole transformation technique. Further, the paper proposes systematic design criteria for a ZPT–CSA with a continuous reset mechanism for the noise reduction. The complete transfer function for the ZPT–CSA is derived and noise model is presented in the presence of interpixel capacitive crosstalk. The results of the mathematical model are compared with the circuit simulations. An average error of 3 × 1 0 − 10 V 2 ∕ Hz is seen in the output noise voltage spectral density for a frequency range of 100 kHz to 100 MHz. The comparison shows an average relative error of 1.8% for the crosstalk voltages. ENC from both the simulations has an average error of 2.91 aC ( ∼ 18 electrons) when plotted for a pixel capacitance range of 10 fF–100 fF in 100 kHz to 100 MHz frequency band.

Dual Parallel Multielectrode Traveling Wave Mach–Zehnder Modulator for 200 Gb/s Intra-datacenter Optical Interconnects

We present a silicon photonic dual parallel multielectrode Mach-Zehnder modulator (MEMZM) based transmitter targeting 200 Gb/s four-level pulse amplitude modulation (PAM4) short reach transceivers. The MEMZMs have an average V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">π</sub> and electro-optic (EO) bandwidth of 5 V and 38 GHz, respectively. The transmitter is characterized versus receiver equalizer taps, received signal power, driving voltage swing, crosstalk voltage swing, bitrate, and reach. Results reveal that using only a three-tap equalizer at the receiver, 100 Gb/s PAM4 net rate per lane can be achieved at a bit error rate (BER) below the KP4 forward error correction (KP4-FEC) threshold of 2.4 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-4</sup> . Moreover, up to 128 Gb/s can be received at a BER below the KP4-FEC threshold using only 2 Vpp and 1 Vpp driving the MEMZM segments. Then, both MEMZMs are driven simultaneously to assess the crosstalk impact on the BER performance at parallel operation. Driven by four binary signals, we demonstrate 200 Gb/s PAM4 transmission over up to 10 km of single mode fiber at a BER below the KP4-FEC threshold.