Output Reference Voltage Research Articles

Low-Temperature Drift Bandgap Reference Based on Exponential Compensation Design

Abstract In analogue and mixed-signal systems, a stable and accurate reference voltage source is essential to ensure system performance. In this paper, a high-precision bandgap reference (BGR) with a high power supply ripple rejection ratio (PSRR) and lowtemperature drift is proposed, which mainly consists of a core circuit, an exponential temperature compensation circuit, a PSRR enhancement circuit and a start-up circuit. The PSRR is improved by using a PSRR enhancement circuit and a low-pass filter. An exponential compensation circuit is used to reduce the temperature drift coefficient of the bandgap reference. Based on a 0.18 μm BCD process for design and simulation, the output reference voltage is 1.203 V with a temperature drift coefficient of 2.635 ppm/°C over the temperature range of −40°C to 125°C. The PSRR is −144.4 dB at a frequency of 10 Hz, and −43.8 dB at a frequency of 1 MHz, and the layout area is 316 μm × 156 μm.

Advanced Multi-Sampling PWM Technique for Single-Inductor MIMO DC-DC Converter in Electric Vehicles

Amongst the various topologies of multi-input multi-output (MIMO) DC-DC converters, single-inductor MIMO (SI-MIMO) converters have the advantages of a reduced component count, a simpler structure, and low cost. These converters are suitable in electric vehicle (EV) applications involving variable ports, essential for performing different functions. Digital control in SI-MIMO converters is promising for enhancing transient performance due to its numerous benefits. However, delays in digital control, particularly computational and pulse width modulation (PWM) delays, can negatively impact the performance of DC-DC converters. Multi-sampling and double PWM update methods can mitigate these control delays, but they often necessitate complex control schemes, adding computational burden. In this work, an advanced multi-sampling PWM technique, integrating sample shift and multi-sampling, is proposed while employing a simple digital PID control scheme. The proposed method was tested for a shared-switch SI-MIMO converter with battery discharging and charging modes in the MATLAB/Simulink environment and compared with the conventional single- and multi-sampling PWM methods. The results demonstrated that the proposed method significantly improved the converter performance, surpassing the conventional single- and multi-sampling PWM methods. In the battery discharging mode, utilizing the proposed method, the output voltage achieved a settling time of 0.075 s in response to a step change in its reference, significantly outperforming multi-sampling, which yielded a settling time of 0.124 s, and single sampling, which exhibited an even longer settling time of 0.898 s. It also demonstrated a minimal overshoot of 0.06 volts compared to 1.5 volts with multi-sampling during the step change in the input voltage. Similarly, in the battery charging mode, upon a step change in the reference output voltage, the proposed method effectively minimized the overshoot of the output voltage to 0.845 volts compared to 1.175 volts with multi-sampling, and it decreased the inductor current settling time to 0.296 s from 0.330 s recorded under multi-sampling. These findings underscore the potential of the proposed method in enhancing the digital control performance of SI-MIMO DC-DC converters in electric vehicles.

Full state observer-based pole placement controller for pulse width modulation switched mode voltage-controlled buck Converter

Switched mode DC-DC converters play an important role in today's renewable energy systems, electric Vehicles, consumer electrical appliances, and many more. While many researchers have designed controllers for DC-DC converters, achieving low implementation cost remains a significant hurdle. This paper proposes a cost-effective observer-based pole placement controller for a PWM voltage-controlled Buck converter with clear step by step design approach. The state space averaged model of the DC-DC power converter is used to design pole placement with integrator compensator and full state observer. Pole placement is employed to improve the transient and steady state behavior of Voltage reference tracking response and full state observer is applied to extract the inductor current with the aim of removing the actual current sensor. Design specifications are set to a settling time of less than 5 msec and an overshoot of less than 5 %. While designing Observer-Controller combination, the separation principle, designing the controller and observer independently, is utilized by placing the observer poles far to the left of the controller poles for the Observer to converge faster. The designed controller and observer is verified with simulation in MATLAB/SIMULINK software and design of developed controller and observer are realized using low-cost analog electronics circuit components The results shows that the proposed system's strength in tracking the reference output voltage even in the presence of input voltage disturbance and the mean value of inductor current is well extracted having only the output voltage and MOSFET gate signal.

A Two-Stage Sub-Threshold Voltage Reference Generator Using Body Bias Curvature Compensation for Improved Temperature Coefficient

Leakage diodes cause deviations in the thermal drift of ultra-low-power two-transistor (2T) reference circuits, resulting in either convex or concave output voltages against temperature, depending on the reference transistor types (n-type/p-type). This paper investigates the combined application of the convexity and concavity properties exhibited by the output voltage of complementary 2T references, one n-type and one p-type. By exploiting the body bias effect, this approach mitigates variations in the output reference voltage caused by temperature fluctuations. Software optimization is also used to obtain the required aspect ratios after formulating the required criteria for drain-induced barrier lowering (DIBL) elimination in the first stage. The performance of the proposed reference is evaluated by post-layout Monte Carlo simulations. In the range of 0 °C to 100 °C, the output reference voltage has an average temperature coefficient (TC) of 26.7 ppm/°C without any temperature trim. The output reference voltage is 195.5 mV with a standard deviation of 13.6 mV. The line sensitivity (LS) is 17.1 ppm/V in the supply voltage range of 0.5 V to 2.1 V at 25 °C. At 25 °C and 0.5 V, the power consumption is 28.8 pW, increasing to a maximum of 1.3 nW at 100 °C and 2.1 V.

Phase-Shifting Adaptive LLC Resonant Converter with Reduced Turn-Off Loss in Wide Voltage Application

In this paper, a hybrid control method with adaptive phase-shifting modulation (PSM) and pulse-frequency modulation (PFM) is proposed to optimize the steady-state performance of an LLC resonant converter in wide voltage-gain range application. For the primary-side switches under the hybrid control method, zero-voltage switching (ZVS) performance is maintained over wide voltage-gain range and the turn-off loss is reduced; therefore, the converter reconciles wide voltage-gain range and high efficiency. Mode characteristics under different phase-shifting-angle-θ and switching-frequency-fs combinations is analyzed, and then the soft-switching characteristic is revealed. By introducing time domain analysis, the turn-on current of the primary-side switches is calculated, and thus the ZVS boundary of different θ and fs combinations is inferred. In addition, to acquire the optimum steady-state operation of the converter, the turn-off current is calculated; by making the converter work near to the minimum turn-off current operating point, the turn-off loss can be reduced greatly. With the principles of achieving ZVS performance and minimizing turn-off current, the phase-shifting angle θ of PSM is designed to be adaptive to the reference output voltage, no additional circuits are needed, and the two control degrees (θ and fs) are simplified to one (fs). The simulation and experiment are developed to verify the feasibility and effectiveness of the hybrid control method; the results show that ZVS performance is maintained at wide voltage-gain range and the turn-off current of the hybrid control method is reduced to that of the single PFM, and thus the turn-off loss is reduced. The efficiency comparison validates the fact that the hybrid control method has less power loss than single PSM and single PFM.

Novel Energy Management Scheme for a Permanent Magnet Electric Drive-Based Hybrid Vehicle Using Model Predictive Control

The present work deals with the design of a traction system for a hybrid vehicle using a PMSM-type motor, including an energy regeneration stage, using a Neutral Point Piloted (NPP) inverter. Optimal operation allows the motor to be supplied in the traction stage with the correct energy in such a way that it operates properly; on the other hand, during braking, it facilitates the transfer of energy in regenerative mode to the DC bus, storing the greatest amount of energy in the storage elements, which, in this case, refers to a battery bank. It also includes a DC-DC bidirectional boost interleaved converter to regulate the DC voltage levels both in traction and in braking. Its fundamental characteristic is that with a reduced number of switching devices, it allows for the reduction in DC voltage of the DC bus with adequate characteristics, constant and stable, regardless of abrupt changes in the output voltage reference value. Also, other features include oscillation control, that is, reducing or increasing oscillations according to operating conditions. Its transient operation is excellent, since the settling time is considerably reduced, which implies that the voltage of the DC bus does not cause mishaps in the operation of the motor. In its operation as a boost converter, in the event of any voltage value of the DC bus, the converter raises the voltage value according to the reference conditions. Similarly, control allows the voltage to be held at a stable value regardless of changes in the set point. This work presents a novel energy management scheme for permanent magnet electric drive based on a Model Predictive Control strategy, thus contributing to the effective energy management of a standard hybrid electric vehicle driving cycle. Results obtained using a real-time Hardware-in-the-Loop (HIL) platform showed the effectiveness of Model Predictive Control in dealing with power flow management while ensuring control of electric drive in all the required speed–torque profiles.

Grid interface control of wind–solar generator in Hail region of Saudi Arabia using FOPI controller

This study investigates the performance of a wind–solar generator (WSG) in the Hail region of Kingdom of Saudi Arabia (KSA) with a fractional order PI controller (FOPI) applied to the grid connection line. The proposed hybrid generator consists of a wind turbine with a PMSM machine and a PV panel connected to a secondary distribution grid by a DC link, three-phase inverter, and an RL filter. The line currents injected into the grid and/or loads are controlled by calculating the output reference voltage of an inverter and by the reference active and reactive requested powers. For this purpose, control loops around the RL filter were developed with fractional-order proportional-integral (FOPI) controllers, and a comparison with classic PI controllers was made. The system was simulated using the MATLAB/Simulink software. The results showed that the generator satisfied the power demand under the climatic conditions of the Hail region. They also demonstrated the good performance of the proposed controllers, which had good tracking accuracy and robustness to variations in wind speed and power demanded by loads in a very short time. The FOPI controller exhibited faster dynamic response and less overshoot than the classic PI controller.

A high performance CMOS voltage reference in one simple circuit

This article introduces a novel CMOS threshold voltage reference with low temperature coefficient (TC) and high power supply rejection ratio (PSRR). A novel structure consisting of the Beta-multiplier and an operational amplifier is used to reduce the influence of power supply ripple on output reference voltage VREF and improve PSRR. A 1.2-V MOS transistor and a 3.3-V MOS transistor are employed to achieve temperature compensation and low TC for the output reference voltage VREF, through the difference in threshold voltage. The proposed voltage reference was designed and simulated using a 90 nm CMOS process, occupying a compact active area of 0.003 mm2. Post-simulation results confirm that the voltage reference output is 494 mV, exhibiting a mean TC of 12.58 ppm/∘C across a temperature range from −40∘C to 125∘C. It consumes a mere 461.4 nA when supplied with 1.2 V at 27∘C. Over a supply voltage range of 0.8 – 1.32 V, the line sensitivity (LS) measures 0.57 mV/V. Remarkably, it achieves a high PSRR exceeding −85.6 dB at 100 Hz.

Adaptive neural network control of DC–DC power converter

This article proposes a novel Zernike radial neural network based adaptive control architecture for the closed-loop control of output DC voltage in DC-DC buck power converter. The proposed combination of novel Zernike radial neural network estimator and the adaptive backstepping controller effectively compensates for wide range of perturbations affecting the converter system, in an online manner. The closed loop stability of the DC-DC buck power converter with the proposed neuro-adaptive backstepping controller is proven by Lyapunov stability criterion. Numerical simulations are conducted to examine the effectiveness of the proposed controller under start-up response and step changes in the load, source voltage and reference output voltage. Furthermore, the simulation findings are validated by conducting extensive real-time investigation on a laboratory prototype, under a wide range of operating points. The results obtained shows a significant improvement in the transient response of both output voltage and inductor current of the converter, relative to the relevant control methods proposed in the recent past.

Lyapunov-Based Control Strategy for a Single-Input Dual-Output Three-Level DC/DC Converter

This paper proposes a robust control strategy using direct Lyapunov strategy (DLS) for a single-input dual-output three-level dc-dc converter (SIDO-TLC) while the output loads and voltage references are disturbed. The first proceeding is to concurrently focus on the current and voltage dynamics of the converter buck and boost segments for exerting the related variable errors to the DLS-based function. Accordingly, through a comprehensive analysis based on the outcome of this proceeding, the PI controller coefficients allotted to the current reference design process are enabled to reach their maximum robustness capabilities against any output voltage variation. Moreover, the converter reference current tracking-based assessment leads to several smooth hyperbolic curves with their unique geometric properties. Consequently, the alteration trend of these curves facilitates the Lyapunov coefficients to be adjusted commensurate with the dynamic operation of the converter while converging to zero steady-state errors. Using a TMS320F28335 digital signal processor (DSP), disparate experimental results are conducted on the SIDO-TLC to verify the accurate and robust performance of the proposed control strategy.

A MOSFET subdivision, MOSFET-only subthreshold voltage and current reference for LDO applications

This paper proposes a MOSFET-only voltage and current reference circuit, which can simultaneously provide a 2 V reference voltage and 300 nA reference current. This design is mainly used in a low-power Low-Dropout Regulator (LDO) project, after simulation verification, which works well in LDO applications. The circuit is performed by SMIC.18 CMOS technology and simulation with the Cadence platform, with different threshold voltage MOSFET circuit design. The whole circuit works in the subthreshold area, and the overall circuit consists of the start-up circuit, the current reference circuit, the voltage reference circuit, the MOSFET subdivision circuit, and the current mirror output circuit. The circuit has the characteristics of high precision and low power consumption, with a layout size of only 0.015 mm2. Under a temperature range of -30 to 70 °C and a power voltage of 3.3 V, the simulation and post-simulation temperature coefficients (TC) of the circuit are 5.4 ppm/°C and 19.4 ppm/°C, respectively. The post-simulation output reference voltage at room temperature is 2.0008 V, and the working power voltage within the circuit error range is 3.2 V to 3.4 V. Excluding the current mirror output circuit part of the Current-Quiescent (IQ) being 530 nA, the power consumption is 1.75 μW when the supply voltage is 3.3 V, and the design goal is reached.

Design of a High PSRR Low-pressure Bandgap Reference Source with Curvature Compensation

Based on the NUVOTON 0.35 μm BCD process, a low voltage bandgap reference with an input voltage of 5 V and output voltage of 0.6 V is designed in this paper. The traditional low-voltage bandgap reference output voltage has a large temperature coefficient and poor ability to suppress power supply fluctuations. In this paper, a circuit with high order compensation is proposed to reduce the temperature coefficient of the circuit, and a pre-regulated circuit is used to increase the power supply rejection ratio. The simulation results are at -30 °C∼130 °C. The output voltage of reference voltage is 947.5 μV, the temperature coefficient is 9.58 ppm/°C, and the power suppression ratio is -104.62 dB, which meets the design requirements of the power management chip.

Design and Optimization of PI Controller for Multiple-output Wireless Electric Vehicle Charger

Abstract: This paper focuses on designing and modeling multiple-output wireless chargers for electric vehicles (EVs). This paper uses a closed loop buck converter to obtain variable output dc voltage of a wireless electric vehicle charger (WEVC). For designing a closed-loop buck converter, a PI controller is used. The tuning of a PI controller for a nonlinear system is a typical task; therefore, in the paper, three optimization techniques such as Krill Herd Optimization (KHO), Harris Hawks Optimization (HHO), and Sparrow Search Optimization (SSO) utilized to find the optimum value of a PI gain parameters (Kp and Ki). Background: Wired charging system is famous but contains problems like unkempt wires and protection concerns in a damp environment. Then a solution to this problem is a wireless charger because it does not contain any exposed wires. Hence it is convenient for charging and intrepid transmission of power in antagonistic environmental conditions. A wireless charger can be used in unmanned electric vehicles. Objective: The objective of this study is to develop a wireless electric vehicle charger at the variable output voltage. The performance analysis by different optimization techniques such as SSO, KHO, and HHO for variable reference output voltage. Methods: Three optimization techniques are used, such as SSO, KHO, and HHO, for obtaining smooth output dc voltage, reducing harmonics, and improving power transfer capability. Results: SSO gives better results for the variable output voltage of the wireless charger. Conclusion: Wireless charger is designed at a variable reference output voltage and SSO-optimized PI-gain parameters of the charger and provides better performance than other optimization techniques, such as HHO and KHO.

A HCI self-healing circuit of a bandgap reference circuit with curvature compensation

In this paper, the performance degradation of a bandgap reference circuit with curvature compensation under the hot carrier injection (HCI) effect is studied, and a self-healing circuit is proposed. The intrinsic performance of the curvature compensation bandgap circuit achieved a temperature coefficient (TC) of 1.949 ppm/°C and an output reference voltage of 384.748 mV under a 1.2 V power supply voltage between −40 °C to 125 °C. The TC of the reference circuit will increase to 8.033 ppm/°C and the output reference voltage decreases to 384.318 mV after 50 years under the HCI effect. The study found that the gain decrease of the op-amp in the reference circuit leads to a decrease in the output voltage, and the decrease of the compensation current in the curvature compensation circuit leads to the degradation of the TC. A self-healing circuit is designed to mitigate the impact of the HCI effect. The simulation results show that the TC of the self-healing reference circuit is 3.934 ppm/°C and the output reference voltage is 384.655 mV after 50 years under the HCI effect.

Nonlinear Cascaded Control for a DC-DC Boost Converter

The Boost Converter is a type of DC-DC converter that operates using switching techniques and is designed to elevate the voltage level. This paper presents a cascaded control for a boost converter to ensure that the inductor current and output capacitor voltage remain in a safe operating zone. Ensuring safe operating conditions and stable closed-loop poles is crucial because it guarantees that both current and voltage remain within the designated operating range. This preventive measure prevents any damage to components like capacitors (C), inductors (L), and switches. Unstable operation, on the other hand, could lead to oscillations and an undesirable increase in the amplitude of current and voltage, posing a risk to all components involved. The research contribution involves an investigation of cascaded control, utilizing power and energy concepts due to their advantageous effects on system performance and design. By implementing nonlinear controllers based on a large-signal averaged model, the closed-loop poles remain independent of operating points, eliminating the need for small-signal linearization. Small-signal linearization makes the controlled system dependent on the operating point. Two controllers are introduced based on power and energy concept, which is easy to understand. The potential practical application of the proposed cascaded control approach is in high-power applications. Tracking the energy stored in the output capacitor is first investigated to validate the proposed control scheme by varying the output voltage reference from 32 V to 50 V. Then, the regulation of the energy voltage is explored by varying the load resistance for the output voltage at 50 V. Both are done using a switched model using MATLAB/Simulink software. Simulation results are given to demonstrate the effectiveness of the proposed method. The key metrics used to assess the effectiveness of the proposed control scheme are the undershoot voltage and robustness. The results show that the studied system's tracking, regulating operations and robustness properties are as expected. The proposed method faces a challenge with the number of sensors required. To address this, observers can be utilized to reduce sensor usage while maintaining measurement accuracy. The proposed method can be applied to other power electronic systems.

A 33-Gb/s/Pin 1.09-pJ/Bit Single-Ended PAM-3 Transceiver With Ground-Referenced Signaling and Time-Domain Decision Technique for Multi-Chip Module Memory Interfaces

A three-level pulse amplitude modulation (PAM-3) transceiver (TRX) with improved simultaneous switching output (SSO) noise and reference voltage margin was studied. PAM-3 signaling with an insertion of 3 bits in 2-unit intervals (UI) was implemented using the upper, under, and ground voltages, achieving 150% pin efficiency. The ground-referenced signaling (GRS) charge pump driver reduced SSO noise and maintained ground as the solitary return current path. Capacitive peaking and middle edge-rate boosting were implemented for transmitter (TX) equalization. With the receiver (RX), the ground level was used as a reference voltage for a single-to-differential (S2D) amplifier. PAM-3 signaling was converted to binary data using the time-domain decision technique in comparators. The decision time of comparators for data and reference voltage was compared. This technique shows the increased voltage margin, the reduced decision time, and the decreased error rate. The reduced decision time improved the performance of the PAM-3 decision feedback equalizer (DFE). A clock disabled the circuit, and a low-power return-to-zero (RZ) to non-RZ (NRZ) converter was configured for the proposed comparator output cases. The prototype TRX was fabricated in a 28-nm complementary metal–oxide silicon (CMOS) process with a surface area of 0.006 mm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{2}$</tex-math> </inline-formula> . The total power efficiency was recorded as 1.09 pJ/b at 33 Gb/s/pin. Through the flame retardant-4 (FR-4) 20-mm printed circuit board (PCB) channel and coaxial cable, a bit error rate (BER) of 10 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{-12}$</tex-math> </inline-formula> was measured.

Power utilization efficiency improvement of distributed energy units in DC microgrids using primal‐dual subgradient method

AbstractTo improve the power utilization efficiency of distributed energy units (DEUs) in DC microgrids, a centralized current iteration regulation approach is presented in this paper. The power utilization efficiency is partially represented by the power losses of DEUs, which can be modelled as quadratic functions of the output currents of DEUs. The power efficiency is also dependent on the line losses on the resistances between the DEUs and DC buses, which can be formulated in the basis of the output currents as well. Thus, the total power losses of DEUs comprise line and converter losses, which are verified to be a constrained‐convex function of the current allocation coefficients. In this paper, a primal‐dual subgradient method (PDSM) using only explicit addition and subtraction iterations is adopted to obtain the optimal current distribution coefficients. On this basis, an adaptive droop regulation scheme is applied to further control the output voltage references of DEUs, and proportional‐integral (PI) controllers are applied to track the adaptive voltages based on the current sharing errors. Both simulation and empirical results demonstrate the effectiveness of the proposed control to improve the power utilization efficiency of DEUs regardless parameter and load variations in DC microgrids.

Robust fixed-order [formula omitted] controller synthesis for multi-phase converters with input voltage feed-forward

Generated DC voltages of batteries, fuel cells, or supercapacitors as power sources connected in series with DC-DC converters change according to operating conditions. In such cases, the output voltage stability of the multi-phase DC-DC converters is an issue, particularly being subject to noises in the input voltage and load current disturbances. Input voltage feed-forward (IVFF) compensation approaches can improve the output voltage stability of the DC-DC converters in such scenarios. This paper proposes a robust fixed-order H∞ based IVFF control framework by considering sensor noise, input voltage, and load current disturbances to improve output voltage stability and reference tracking performance. The mismatched disturbance transfer functions depending on parasitic resistances are derived to include in the controller synthesis process. An iterative convex-concave optimization-based robust fixed-order controller design algorithm is proposed to optimize the feedback and feed-forward controllers under the stability and performance constraints. This algorithm allows the designing of the controllers simultaneously. The feed-forward controller, whose structure is independent of the system transfer functions, is optimized without any model inversion or extra design steps. The performance of the proposed controller is compared with an integral linear quadratic regulator controller, a sliding mode PID controller augmented with a nonlinear disturbance observer, and a fixed-order robust controller designed with non-smooth techniques. Real-time implementation of the fixed-order control systems is performed on a 2-leg 200 W interleaved boost converter. The performances are discussed under external disturbance effects to show the validity of the proposed control approach.

Analysis and Control of Chaos in Voltage Mode Control Superbuck Converter for Photovoltaic Systems

Superbuck converter is a high-order converter with complex nonlinear dynamic characteristics, such as bifurcation and chaos, which will affect the stability of photovoltaic power generation systems. In this paper, the nonlinear dynamics of the voltage mode control Superbuck converter are studied. Taking reference voltage, input voltage, and output voltage error amplification factor as bifurcation parameters, the evolution process of the system from a stable state to bifurcation to a chaotic state is analyzed. The bifurcation forms of the converter under three bifurcation parameters are all period-doubling bifurcations. In this paper, the linear sliding mode control method is used to suppress and clear the nonlinear phenomenon of the system so that the converter in the chaotic state and unstable operation state can be restored to a stable single-cycle state in about 0.6ms.

A new adaptive dead time compensation method for dual three-phase permanent magnet synchronous motor

This paper proposes a new adaptive dead time compensation method for dual three-phase permanent magnet synchronous motors with two sets of three-phase windings spatially shifted by 30 electrical degrees. The stator resistance and leakage inductance are the only 5th and 7th harmonic impedances in the dual three-phase motor, which leads to a more pronounced current distortion due to dead time in the dual three-phase motor than in the three-phase motor. Therefore, dead-time compensation has significant implications for the application of dual three-phase motors. In this paper, the minimum value tracking algorithm is used to adjust the compensation voltage amplitude adaptively, and the compensation voltages are added to the output reference voltage in stationary frames. The proposed computation method has some significant advantages, such as simple implementation without additional hardware, easy mathematical computations, and no offline experimental measurements. Simulation results are provided to validate the performance of the proposed method.