Abstract: Sensing systems such as biomedical implants, infrastructure monitoring systems, and military surveillance units are constrained to consume only picowatts to nanowatts in standby and active mode, respectively. This tight power budget places ultra-low power demands on all building blocks in the systems. This work proposes a voltage reference for use in such ultra-low power systems, referred to as the 2T voltage reference, which has been demonstrated in silicon across three CMOS technologies. Prototype chips in 0.13 μm show a temperature coefficient of 16.9 ppm/°C (best) and line sensitivity of 0.033%/V, while consuming 2.22 pW in 1350 μm2. The lowest functional Vdd 0.5 V. The proposed design improves energy efficiency by 2 to 3 orders of magnitude while exhibiting better line sensitivity and temperature coefficient in less area, compared to other nanowatt voltage references. For process spread analysis, 49 dies are measured across two runs, showing the design exhibits comparable spreads in TC and output voltage to existing voltage references in the literature. Digital trimming is demonstrated, and assisted one temperature point digital trimming, guided by initial samples with two temperature point trimming, enables TC <; 50 ppm/°C and ±0.35% output precision across all 25 dies. Ease of technology portability is demonstrated with silicon measurement results in 65 nm, 0.13 μm, and 0.18 μm CMOS technologies.

Abstract: This paper presents a new digital control scheme for a standalone photovoltaic (PV) system using fuzzy-logic and a dual maximum power point tracking (MPPT) controller. The first MPPT controller is an astronomical two-axis sun tracker, which is designed to track the sun over both the azimuth and elevation angles and obtain maximum solar radiation at all times. The second MPPT algorithm controls the power converter between the PV panel and the load and implements a new fuzzy-logic (FLC)-based perturb and observe (P&O) scheme to keep the system power operating point at its maximum. The FLC-MPPT is based on a voltage control approach of the power converter with a discrete PI controller to adapt the duty cycle. The input reference voltage is adaptively perturbed with variable steps until the maximum power is reached. The proposed control scheme achieves stable operation in the entire region of the PV panel and eliminates therefore the resulting oscillations around the maximum power operating point. A 150-Watt prototype system is used with two TMS320F28335 eZdsp boards to validate the proposed control scheme performance.

Abstract: This paper presents a novel grid-connected boost-half-bridge photovoltaic (PV) microinverter system and its control implementations. In order to achieve low cost, easy control, high efficiency, and high reliability, a boost-half-bridge dc-dc converter using minimal devices is introduced to interface the low-voltage PV module. A full-bridge pulsewidth-modulated inverter is cascaded and injects synchronized sinusoidal current to the grid. Moreover, a plug-in repetitive current controller based on a fourth-order linear-phase IIR filter is proposed to regulate the grid current. High power factor and very low total harmonic distortions are guaranteed under both heavy load and light load conditions. Dynamic stiffness is achieved when load or solar irradiance is changing rapidly. In addition, the dynamic behavior of the boost-half-bridge dc-dc converter is analyzed; a customized maximum power point tracking (MPPT) method, which generates a ramp-changed PV voltage reference is developed accordingly. Variable step size is adopted such that fast tracking speed and high MPPT efficiency are both obtained. A 210 W prototype was fabricated and tested. Simulation and experimental results are provided to verify the validity and performance of the circuit operations, current control, and MPPT algorithm.

Abstract: A novel low-energy tri-level switching scheme for low-power successive approximation register (SAR) ADC is proposed. With the input common-mode voltage ( Vcm ) designed to be exactly half of the reference voltage ( Vref ), the switching energy of the proposed switching scheme is reduced by 96.89% as compared with the conventional architecture. Besides the large energy saving, the proposed switching scheme also reduces the number of capacitors in the ADC capacitor array by 75%, which in turn results in an area-efficient SAR ADC.

Abstract: We present an ultra low power (200 nA current consumption) reverse bandgap voltage reference operational from supply voltages down to 0.75 V. The reference is a part of microprocessor system on chip implemented in a digital 130 nm CMOS process and has a total area of 0.07 mm2. The reference accuracy is ± 2.5% (5 sigma) over a temperature range of - 20 to 85°C without trimming. With trimming ± 0.5% accuracy is achieved.

Abstract: This paper presents a trim-free low-voltage and low-power CMOS current reference which achieves high current stability to temperature variation. In order to achieve process-insensitive temperature compensation, the proposed circuit employs ratio between the process-independent temperature coefficients of resistor and compensation voltage. The proposed current reference is implemented in 0.18-μm CMOS technology and consumes 1.4 μW from a 1-V supply. It achieves temperature coefficient of 24.9 ppm/°C with 0 °C to 100 °C of temperature variation without trimming, which is the lowest among the recently reported CMOS current references.

Abstract: An OLED display device which can sense a current of each pixel at high speed by a simple structure in order to compensate for luminance non-uniformity and a pixel current sensing method thereof are discussed. The OLED display device includes a display panel including pixels, each including a light emitting element and a pixel circuit for independently driving the light emitting element, a data driver for driving a data line connected to the pixel circuit using a data voltage, floating one of the data line, a reference line for supplying a reference voltage to the pixel circuit, and a power line for supplying a power to the pixel circuit to use the floated line as a current sensing line, sensing a voltage corresponding to a pixel current of the pixel circuit flowing to the current sensing line, and outputting the sensing voltage, in a sensing mode.

Abstract: A constant voltage maximum power point (MPP) algorithm that automatically adjusts the reference voltage to account for varying environmental conditions is presented. A simple (and inexpensive) analog feedforward PWM controller is developed to continuously track the MPP of a solar cell array as the weather conditions vary. The solar array source is configured such that its open-circuit voltage is sampled without breaking the entire source from the load as is the case with other constant voltage MPP algorithms. MATLAB/Simulink simulations are presented to demonstrate the performance of the proposed MPP algorithm. Simulation results collaborated with experimental results using a DC motor load.

Abstract: A method includes, in a data storage device that includes a non-volatile memory, reading first data values from memory elements of the non-volatile memory using a set of reference voltages that includes a first reference voltage, and determining a first error count associated with the first reference voltage. The method includes reading second data values from the group of memory elements using a set of modified reference voltages that includes a modified first reference voltage, and determining a modified error count associated with the modified first reference voltage. The method includes updating the set of reference voltages to include the first reference voltage or the modified first reference voltage based on a comparison of the error count to the modified error count.

Abstract: One embodiment relates to a receiver circuit for multi-level amplitude signaling which includes at least three amplitude levels for each symbol period. The receiver circuit includes a peak detector, a reference voltage generator, and a comparator circuit. The peak detector is arranged to detect a peak voltage of the multi-level amplitude signal, and the reference voltage generator uses the peak voltage to generate multiple reference voltages. The comparator circuit uses the multiple reference voltages to detect an amplitude level of the multi-level amplitude signal. Other embodiments and features are also disclosed.

Abstract: A system including is plurality of resistors, a plurality of comparators, and a decoder module. The resistors are connected in series between a supply voltage and a common voltage. A first input of each comparator is connected to a reference voltage. A second input of each comparator is respectively connected to one of a plurality of nodes between the resistors. The decoder module is configured to receive an output from each comparator and to output a plurality of bits based on the output of each comparator. Each of the plurality of bits indicates a different one of a plurality of voltage ranges. A present value of the supply voltage lies in one of the plurality of voltage ranges.

Abstract: An Li-ion battery charger based on a charge-control buck regulator operating at 2.2 MHz is implemented in 180 nm CMOS technology. The novelty of the proposed charge-control converter consists of regulating the average output current by only sensing a portion of the inductor current and using an adaptive reference voltage. By adopting this approach, the charger average output current is set to a constant value of 900 mA regardless of the battery voltage variation. In constant-voltage (CV) mode, a feedback loop is established in addition to the preexisting current control loop, preserving the smoothness of the output voltage at the transition from constant-current (CC) to CV mode. A small-signal model has been developed to analyze the system stability and subharmonic oscillations at low current levels. Transistor-level simulations of the proposed switching charger are presented. The output voltage ranges from 2.1 to 4.2 V, and the power efficiency at 900 mA has been measured to be 86% for an input voltage of 10 V. The accuracy of the output current using the proposed sensing technique is 9.4% at 10 V.

Abstract: An OLED display device is provided. The OLED display device includes a first transistor connected to a data line and a first node; a second transistor connected to the first node and a second node; a third transistor connected to a reference voltage terminal and a third node; a fourth transistor connected to an initialization voltage terminal and the second node; a fifth transistor connected to the reference voltage terminal and the second node; a driving transistor; and an OLED connected to a low-level power supply voltage terminal and the second node. The driving transistor has a source connected to the second node, a gate connected to the third node, and a drain connected to a high-level power supply voltage terminal.

Abstract: A charge pumping apparatus includes a voltage pumping unit for pumping an input voltage, a voltage pumping control unit for controlling the voltage pumping unit according to a comparison result between the input voltage and an input criterion voltage and a comparison result between an output voltage output from the voltage pumping unit and an output criterion voltage, and an optimum power point tracking unit for tracking an optimum power point in the case of detecting that the output voltage decreases lower than the output criterion voltage, and adjusting an input impedance to change the input criterion voltage to a voltage corresponding to the optimum power point, wherein the optimum power point is a power point where an input power according to the input voltage becomes a maximum. Since the optimum power point is tracked by measuring only a voltage without a current sensor, a power loss is small.

Abstract: A novel temperature-stable nonbandgap voltage reference, which is compatible with standard CMOS technology, is presented in this brief. No diodes or parasitic bipolar transistors are used. Based on mutual temperature compensation of the threshold voltages of nMOS and pMOS transistors, a temperature-insensitive voltage reference with significant reduction in temperature dependence of mobility is achieved without using subthreshold characteristics. The problem of a fixed voltage reference value is also avoided by different parameter design. Experimental results of the proposed voltage reference implemented with a 0.35-μm CMOS process demonstrate that the output of the voltage reference is 847.5 mV, a temperature coefficient of 11.8 ppm/°C with a temperature range from 0 °C to 130 °C is obtained at 3-V power supply, a power-supply noise attenuation of 72 dB is achieved without any filtering capacitor, and the line regulation is better than 0.185 mV/V from 1.8-V to 4.5-V supply voltage dissipating a maximum supply current of 8 μA. The active area of the presented voltage reference is 90 μm ×120 μm.

Abstract: An electric vehicle includes a controller configured to receive sensor feedback from a high voltage storage device and from a low voltage storage device, compare the sensor feedback to operating limits of the respective high and low voltage storage device, determine, based on the comparison a total charging current to the high voltage storage device and to the low voltage storage device and a power split factor of the total charging current to the high voltage device and to the low voltage device, and regulate the total power to the low voltage storage device and the high voltage storage device based on the determination.

Abstract: A hysteretic mixed-signal controller for high-frequency switch-mode power supplies that achieves both very fast transient response and constant switching frequency under steady-state operation is presented. The mixed-signal controller combines three control loops: analog nonlinear current loop, digital linear voltage loop, and digital frequency loop. To eliminate the sampling delay associated with conventional digital controllers and improve the transient response performance, the fast nonlinear loop is built with a simple analog hardware. The nonlinear current loop is designed based on the hysteretic control of the output capacitor current. To guarantee the constant switching frequency, under different operating conditions, a digital frequency loop is proposed and implemented. The digital frequency loop eliminates undesirable switching frequency variation, associated with the conventional hysteretic controllers, by digitally adjusting the hysteretic bands around the output voltage reference. The controller operation is experimentally verified with a 5-MHz buck converter. Experimental results demonstrate fast transient response while the constant switching frequency is maintained under steady-state operation.

Abstract: A pixel circuit of an OLED display device is disclosed. The pixel circuit includes a light emitting element, a driving TFT for driving the light emitting element, a delivery capacitor connected between a first node and a second node, a storage capacitor connected between the second node and a third node, a first reset TFT for initializing the first node to a reference voltage in response to a first reset signal from a first reset line, a second reset TFT for initializing the third node to an initialization voltage in response to the first reset signal from the first reset line, a third reset TFT for initializing the second node to the reference voltage in response to a second reset signal from a second reset line, and a switching TFT for supplying a data voltage to the first node in response to a scan signal from a scan line.

Abstract: An oscillator having: a transistor; a resonant circuit coupled between an output electrode of the transistor and a control electrode of the transistor; and a dc bias circuit for the transistor. The dc bias circuit comprises: a voltage producing circuit and a differential amplifier. The differential amplifier includes: a first input coupled to a fixed reference voltage; a second input coupled to the voltage producing circuit, such voltage producing circuit producing a voltage at the second input of the difference amplifier related to current passing through the output electrode of the transistor; and an output coupled to the control electrode of the transistor.

Abstract: Outstanding GaN-based HFETs (HFET: Heterojunction Field-Effect Transistors) [1] power devices are expected to replace all Si power devices in high power applications such as inverter systems due to their excellent performance In order to exploit the full potential of such emerging GaN power devices, the gate driver that controls the device by a pulse width modulation (PWM) signal is becoming more important The vital function of the gate driver is to provide an isolated gate signal against the reference source voltage that operates at high voltage In addition to this function, their integration with GaN power HFETs is also desirable to achieve smaller system size, lower cost and user-friendliness Although there are several signal isolation techniques for a gate driver such as to use a photo-coupler and wireless pulse transformer [2], these techniques have disadvantages such as large system size and difficulty in integration Other bootstrap or charge pump techniques [3] in high voltage gate drivers (HVIC) have been developed to generate a reference voltage, but the driver can only be used in particular applications such as inverters Meanwhile, we have focused our attention on the recent technology of wireless power transmission using an electromagnetic resonant coupler (EMRC) [4] with an open-ring resonator [5], which is very attractive due to its high efficiency in power transmission and its compactness at high frequency

Abstract: A double-loop control mechanism is developed for an inverting buck-boost converter. The robust converter is capable of operating in a wide range of reference voltage and load resistance with unmodelled parameters. The cause of the non-minimum phase behaviour is analysed. The boundary layer width of the output voltage in sliding mode is found to be dependent on the circuit and control parameters. The speeds of the inner and outer loop are quantitatively determined and compared. The transient responses of the circuit are forecastable. The controller is validated on a simulation circuit.

Abstract: An embodiment of a charger may include an input, at least one switch having a first node coupled to a reference voltage, a current sensor coupled between the input and a second node of the at least one switch, an output coupled to a third node of the at least one switch, and a charge controller coupled to the input to determine an input voltage, to the current sensor to determine an input current and to control inputs of the at least one switch. The at least one switch may be responsive to control signals supplied by the charge controller to the control inputs thereof to control voltage and current at the output of the charger. The charge controller may be responsive to the input voltage and the input current to produce the control signals in a manner that maximizes electrical power drawn at the input.

Abstract: A high voltage isolation protection device for low voltage communication interface systems in mixed-signal high voltage electronic circuit is disclosed According to one aspect, the protection device includes a semiconductor structure configured to provide isolation between low voltage terminals and protection from transient events The protection device includes a thyristor having an anode, a cathode, and a gate, and a thyristor cathode-gate control region that is built into the protection device The protection device is configured to provide multiple built-in path-up to power-high terminals and path-down to power-low terminals at different voltage levels The protection device also includes independently built-in discharge paths to the common substrate that is connected to a different power-low voltage reference The conduction paths may be built into a single structure with dual isolation regions As a result, the protection device enables superior robustness and compact protection solutions for smart power applications

Abstract: A method of defining a quasi iso-gain supply voltage function for an envelope tracking system is disclosed. The method includes a step of capturing iso-gain supply voltage values versus power values for a device under test (DUT). Other steps involve locating a minimum iso-gain supply voltage value, and then replacing the iso-gain supply voltage values with the minimum iso-gain supply voltage value for corresponding output power values that are less than an output power value corresponding to the minimum iso-gain supply voltage value. The method further includes a step of generating a look-up table (LUT) of iso-gain supply voltage values as a function of input power for the DUT after the step of replacing the iso-gain supply voltage values with the minimum iso-gain supply voltage value for corresponding output power values that are less than an output power value corresponding to the minimum iso-gain supply voltage value.

Abstract: The electromechanical interface is a synchronous machine, because its field winding permits direct management of the magnetization during speed variations. For systems with a common dc-link for the drive and excitation converters, the efficiency is increased if the excitation drive has boosting capability. It is shown that with the proposed control strategy the Z-source converter is suitable for this application, becoming a better alternative than the typically used buck converter. The Z-source converter, in combination with the proposed multiloop control law, can achieve the desired voltage reference swing and high-performance tracking. An analytical comparison between the dominant losses of the buck topology, typically used in FESS, and the Z-source converter shows that the latter has higher efficiency for this application. The parameters of the converter prototype were experimentally identified and used to implement the proposed controller. The control strategy uses the two duty cycles as manipulated variables, one to allow tracking fast changes in the reference signal and the other to adapt the system to the slow changes. The combined action on both inputs contribute to the compensation of the nonminimum phase response of the Z-converter. Experimental results show the potential of the controller for tracking typical FESS application waveforms.

Abstract: Todays ICs usually employ one bandgap voltage reference (BGVR) circuit to generate a well defined voltage that is reused at many places in that IC. The classical BGVR generates a reference voltage that is slightly larger than the material bandgap: a little above 1200mV in silicon. For deep-sub-micron technologies the supply voltage is about the same as the material bandgap which prevents using the classical bandgap structure. As a solution a number of BGVR topologies that create a sub-1V are invented; most of them are based on the structure introduced by Banba [1], some are using resistive voltage division [2] or voltage averaging [3]. For low-power operation high-ohmic resistors (occupying a large area!) must be used in all these techniques, leading to an immediate trade-off between power consumption and chip-area. This trade-off prevents the local generation of reference voltages where they are required: either the power penalty or the area penalty would be too significant. Alternative topologies that do not require high-ohmic resistors typically are not-BGVR-based circuits relying on threshold voltages and hence require trimming to achieve low spread.

Abstract: The invention provides a reactive voltage control system and a reactive voltage control method for a wind power field of the double-fed wind power-generating unit. The system comprises dispatching center equipment, a power management module for the wind power field and a plurality of controllers for the double-fed wind power-generating unit, wherein the dispatching center equipment is used for calculating a reactive power set value of the wind power field according to real-time monitored voltage and active power at a control point of the wind power field and a reference voltage; the power management module for the wind power field is used for distributing the reactive power set value in the wind power field; and the plurality of controllers for the double-fed wind power-generating unit are used for controlling corresponding double-fed wind power-generating unit to perform reactive power compensation according to the reactive voltage value of the double-fed wind power-generating unit distributed by the power management module for the wind power field. According to the reactive voltage control system and the reactive voltage control method for the wind power field of the double-fed wind power-generating unit, the reactive output capability of the double-fed wind power-generating unit can be fully exerted, the cost of reactive power compensation equipment of the wind power field is reduced, and the purpose of controlling the voltage of the wind power field is fulfilled by mutual coordination and control of the dispatching center equipment, the power management module for the wind power field and the plurality of controllers for the double-fed wind power-generating unit.

Abstract: A mobile terminal and an interface method thereof for connecting external devices, such as an adapter, a Universal Serial Bus (USB) cable, a docking station, an accessory, and the like, to the mobile terminal are provided. The mobile terminal includes a battery, a connector including a pin for data communication and first and second power pins for charging the battery, a memory for storing a reference voltage indicating a dedicated adapter of the battery, and a controller for receiving a voltage input from the first and second power pins, for recognizing an external device connected with the connector as the dedicated adapter when a voltage input from the pin for data communication is the reference voltage, and for charging the battery with power input to the first and second power pins.

Abstract: A circuit can include a comparator, a resistor divider, a control circuit, and a multiplexer. The comparator compares an internal supply voltage of the circuit to a selected reference voltage. The resistor divider generates reference voltages. The control circuit receives an output signal of the comparator and generates a select signal. The multiplexer transmits one of the reference voltages from the resistor divider to the comparator as the selected reference voltage in response to the select signal.