Showing papers on "Voltage multiplier published in 2009"

Buck boost function based on a capacitor bootstrap input buck converter

Abstract: A buck boost voltage converter circuit has a capacitor pump circuit for boosting an input voltage in a first mode of operation when an input voltage is below a desired voltage level A buck converter circuit provides the output voltage responsive to the boosted input voltage from the capacitor pump circuit in the first mode of operation and provides the output voltage responsive to the input voltage in a second mode of operation when the input voltage is above the desired voltage level

A Long-Range UHF-Band Passive RFID Tag IC Based on High- $Q$ Design Approach

Abstract: We present a fully integrated long-range UHF-band passive radio-frequency-identification tag chip fabricated in 0.35-mum CMOS using titanium (Ti/Al/Ta/Al)-silicon Schottky diodes. The diodes showed low turn-on voltages of 95 and 140 mV for diode currents of 1 and 5 muA, respectively. In addition, the Schottky diodes exhibited low-resistive loss, and a high-Q -factor design approach was exploited to achieve a long read range for the tag integrated circuit (IC). An optimized voltage multiplier resulted in an excellent sensitivity of -14.8 dBm and corresponding power-conversion efficiency of 36.2% for generating an output voltage of 1.5 V at 900 MHz. The range analysis of the measured multiplier performance indicated an operating range of more than 9 m at 4-W Effective Isotropically Radiated Power reader power. The subthreshold-mode operation of an ASK demodulator allowed ultralow power operation. Under power consumption as low as 27 nW, the demodulator supported a data rate of 150 kb/s and a modulation depth of 40%. A new architecture for generating a stable system clock (2.2 MHz) for the tag IC was employed to deal with supply voltage and temperature variations. Measurements showed that the clock generator had an error of 0.91% from the center frequency owing to an 8-b digital calibration scheme.

A New CMOS Analog Front End for RFID Tags

Abstract: This paper presents a new CMOS integrated analog front-end circuit for 13.56-MHz radio-frequency identification tags. The proposed analog front end consists of a novel CMOS rectified voltage multiplier, a voltage regulator, and a new frequency-shift keying (FSK) demodulator. The proposed single-stage rectifier employing only a PMOS/NMOS pass transistor, an inverter, and one capacitor gets minimal active area and enhances the power conversion efficiency. Moreover, a new technique is used in the proposed FSK demodulator, which includes the data recovery circuit, the multiplexer, the shift register, the phase frequency detector, and the charge-pump circuit. The analog front end has been fabricated in a CMOS 0.35-mum 2P4M technology. The demodulator circuit supports a data rate of 10 kb/s to 1 Mb/s. The power consumption is as low as 0.96 mW, and the chip area without pads is only 0.74 mm times 0.43 mm. Experimental results show that the proposed analog front end works well and confirms the theoretical analysis.

Power converter start-up circuit

Abstract: A power converter arrangement configured to convert a direct voltage into an alternating voltage to be supplied to a grid includes a photovoltaic generator configured to generate the direct voltage, a voltage intermediate circuit, a main power converter connected in series with a bypass switch, a maximum power point controller configured to set a maximum power point voltage, and at least one voltage-limited additional circuit configured to be active during a start-up phase of the photovoltaic generator. The at least one voltage-limited additional circuit and the main power converter are configured as a voltage divider in parallel with the photovoltaic generator. The at least one voltage-limited additional circuit is configured as a capacitive voltage divider having a first capacitor and an intermediate circuit capacitor connected in series.

Power generation system and method for storing electrical energy

Abstract: A power generation system (10) and a method for storing electrical energy are provided. The method includes generating a first AC voltage from a wind turbine generator (22) and converting the first AC voltage to a first DC voltage, utilizing a rectifier (40). The method further includes routing the first DC voltage through a DC voltage bus (41) to an inverter (42) of the power converter (24), and converting the first DC voltage to a second AC voltage utilizing the inverter (42) and outputting the second AC voltage to an electrical grid (12) in response to a first control signal from a power converter controller (46). The method further includes receiving the first DC voltage from the DC voltage bus at a DC-DC converter (44) operably coupled to the DC voltage bus (41), and storing electrical energy from the first DC voltage in a battery storage unit (26) utilizing the DC-DC converter (44) in response to a second control signal.

System and method for synchronous rectifier

Abstract: A synchronous rectification circuit for a power converter includes a power switch coupled to a transformer and an output capacitor and a switching control circuit configured to provide a control signal to the power switch in response to a first state and a second state of the voltage across the power switch. In the switching control circuit, the second state is determined prior to the first state is determined. In an embodiment, the switching control circuit includes a voltage comparing unit configured to act in response to the first and second inputs. The voltage comparing unit is also configured to output a logic signal according to the voltage difference between the sensed voltage drop across the power switch and a reference threshold voltage. A logic processing circuit is coupled to the voltage comparing unit and configured to provide the first state and the second state of the voltage across the power switch.

Single-Stage Soft-Switching Converter With Boost Type of Active Clamp for Wide Input Voltage Ranges

Abstract: A single-stage soft-switching converter is proposed for universal line voltage applications. A boost type of active-clamp circuit is used to achieve zero-voltage switching operation of the power switches. A simple DC-link voltage feedback scheme is applied to the proposed converter. A resonant voltage-doubler rectifier helps the output diodes to achieve zero-current switching operation. The reverse-recovery losses of the output diodes can be eliminated without any additional components. The DC-link capacitor voltage can be reduced, providing reduced voltage stresses of switching devices. Furthermore, power conversion efficiency can be improved by the soft-switching operation of switching devices. The performance of the proposed converter is evaluated on a 160-W (50 V/3.2 A) experimental prototype. The proposed converter complies with International Electrotechnical Commission (IEC) 1000-3-2 Class-D requirements for the light-emitting diode power supply of large-sized liquid crystal displays, maintaining the DC-link capacitor voltage within 400 V under the universal line voltage (90-265 Vrms).

A performance comparison of dickson and fibonacci charge pumps

Abstract: This paper presents an analysis of two types of integrated charge pumps, Dickson and Fibonacci. The two circuits are compared in slow-switching conditions and at equal area occupation. A formula is developed for optimizing the capacitor sizes and improving the performance of the Fibonacci charge pump. The performance is evaluated with focus on voltage gain and output resistance and including the effects of parasitic capacitances.

Implementation of a Voltage Multiplier Integrated HID Ballast Circuit With Dimming Control for Automotive Application

Abstract: High-intensity discharge (HID) lamps are becoming popular substitutes for halogen lamps in automotive headlamps because of the high lumen/watt ratio and the color of the light. In this paper, a ballast (integrated with a voltage multiplier circuit in the secondary winding of the dc converter transformer) with dimming control is presented. The proposed circuit not only eliminates one auxiliary winding but also reduces the voltage across the switch on the primary side and consequently permits the selection of switches with a lower rating. A brief review of the HID circuits is done and compared with the proposed circuit. Experimental results from the prototype are presented. This paper also presents different methods of dimming the automotive HID lamps based on analog and digital control and discusses the relative merits of each of the methods. The dimming control is implemented using both the methods, and experimental results are presented. It is envisaged that the dimming control will provide some flexibility to drivers in the control of HID lamps to suit the driving conditions in the modern cities that are very well lit at night. This paper investigates the merits of each method and discusses the practical issues for implementing such controls.

Switching Power-Supply Device

Abstract: A switching power supply device includes: a transformer having a primary winding, a secondary winding and an auxiliary winding; a switching element connected to the primary winding of the transformer; a control circuit that performs an ON/OFF control for the switching element in a case where a voltage is inputted to the primary winding of the transformer, thereby induces voltages in the secondary winding and auxiliary winding of the transformer; a rectifying/smoothing circuit for rectifying and smoothing the voltage induced in the secondary winding of the transformer and outputting the voltage to a load; an auxiliary power supply circuit that rectifies and smoothes the voltage induced in the auxiliary winding of the transformer, and charges a capacitor owned by the auxiliary power supply circuit with the voltage to thereby supply power to the control circuit; and a starting circuit that supplies a current to the capacitor of the auxiliary power supply circuit in a case of starting the control circuit and in a case where the load is light and the switching element is turned off.

Motor control system including electrical insulation deterioration detecting system

Abstract: A motor control system of the present invention includes an accurate electrical insulation deterioration detecting system. A voltage divider circuit is arranged between a negative DC output portion and a ground, through a normally open switch circuit. A detecting operation control section closes the normally open switch while a circuit breaker is opened, and places at least one of transistors electrically connected to a positive DC output portion into a conductive state, from among six transistors included in three arm circuits. A voltage across the first resistor is inputted as a divided voltage into a voltage comparator of a voltage comparison section. The voltage comparison section compares a divided voltage outputted from the voltage divider circuit and a reference voltage using the voltage comparator and outputs an alarm signal if the divided voltage exceeds the reference voltage.

Adaptive electromagnetic energy harvesting circuit for wireless sensor application

Abstract: This paper presents a microcontroller controlled electromagnetic energy harvesting system suitable for harvesting energy from a single HV transmission line with current between 65A and 130A.The system comprises of magnetic power generator, standard voltage multiplier circuit, DC-DC boost converter and microcontroller. An adaptive algorithm has been applied to the microcontroller to adjust the duty cycle of the converter to achieve maximum output power. This enables the harvesting system to convert and store low voltage sinusoidal power induce from magnetic power generator into the battery for energizing various low power applications. The implemented system is able to operate with minimum sinusoidal induced voltage as low as 1V and can generate 58mW at 65 mA line current. Furthermore, simulation and experimental result as well as mathematical analysis are also included in this paper.

Low voltage low power wide range fully differential CMOS four-quadrant analog multiplier

Abstract: A new low voltage low power fully differential CMOS four-quadrant analog multiplier based on the operation of MOS transistors in saturation region is given. The proposed four-quadrant voltage-mode multiplier was confirmed by using PSPICE simulation and 0.25µm CMOS technology and found to have good linearity with wide input dynamic range. The static power consumption is 0.326 mW, the input voltage range is ±0.75 V from ±1V supply, the bandwidth is 16MHz at 1KΩ//10pF load, the output referred noise voltage is less than 10 nV/√Hz in 1KΩ, and the maximum linearity error is less than 1 % at ±0.5 V input voltage.

Effect of parasitic components in the integrated boost-flyback high step-up converter

Abstract: The increasing interest for renewable energy sources like those based on photovoltaic panels and fuel-cells have driven the power electronics community toward the study and development of high step-up dc-dc converters, able to efficiently interface the low voltage side of such energy sources with the high-voltage dc link side of the grid connected inverter. Between the different investigated topologies, those based on the combination of a boost section and a flyback one are quite interesting, thanks to the possibility to boost the output voltage while keeping the switch voltage stress at a reasonable level. However, the analysis reported in literature always neglect the effect of parasitic components that strongly modify the converter behavior. In this paper, the analysis of the integrated boost-flyback converter with voltage multiplier is presented that includes the effect of the parasitic components. It is shown that a resonance occurs that helps to increase the converter's voltage gain. Experimental results taken from a 300W rated prototype are included, showing a good agreement with the theoretical expectations.

Semiconductor device having single-ended sensing amplifier

Abstract: A semiconductor device has a DRAM cell configured from an information charge accumulating capacitor and a memory cell selecting transistor, the threshold voltage value of a MOS transistor that constitutes a sense circuit is monitored, and the monitored threshold voltage value of the MOS transistor is converted through the use of a transfer ratio that is determined based on the capacitance of the information charge accumulating capacitor and the parasitic capacitance of the bit line. The converted voltage value is level-shifted so that the pre-charge voltage of a pre-charge circuit is a pre-set voltage, a current feeding capability is added to the level-shifted voltage value, and the voltage is fed as the pre-charge voltage.

Switched capacitor voltage regulator with high efficiency over a wide voltage range

Abstract: In some embodiments, a voltage regulator device may include a switched capacitor voltage regulator to receive an input voltage and to provide an output voltage to a load, and a control unit to receive information related to a desired output voltage for the switched capacitor voltage regulator and to determine a desired input voltage for the switched capacitor voltage regulator based on the desired output voltage and selected operation mode or modes of switched capacitor voltage regulator. Other embodiments are disclosed and claimed.

High efficiency boost LED driver with output

Abstract: A current driver for powering a string of LEDs has a boost converter coupled to an input voltage source. A voltage multiplier circuit is coupled to the boost converter and to the string of LEDs. A latch is provided having an output coupled to the boost converter. A current sense element is coupled to the boost converter. A current comparator is provided having an output coupled to a first input of the latch, a first input coupled to the current sense element, and a second input coupled to a reference current. A zero-volt detector circuit is provided having an output coupled to a second input of the latch and an input coupled to the boost converter and the voltage multiplier circuit.

Apparatus for feeding electrical energy into a power grid and DC voltage converter for such an apparatus

Abstract: The apparatus for feeding electrical energy into a power grid ( 8 ) with a DC voltage converter ( 2 ) intended for connection to a DC voltage generator ( 1 ) and with an inverter ( 3 ) connected thereto and intended for connection to a power grid ( 8 ), wherein the inverter contains a bipolar voltage intermediate circuit with two capacitors (C 1 , C 2 ) that are placed in series and are connected together at a ground terminal (E 3 ) intended for connection to a terminal of the DC voltage generator ( 1 ). The DC voltage converter ( 2 ) comprises at least two diodes (D 3 , D 4 ), one switch and one storage choke ( 16 ) which is charged by the DC voltage generator ( 1 ) when the switch is closed and is discharged via the capacitors (C 1 , C 2 ) and the diodes (D 3 , D 4 ) when the switch is open. On the one side, the storage choke ( 16 ) forms, together with two switches (S 3 , S 4 ), a first electric circuit intended for charging said storage choke ( 16 ), the electric circuit being adapted for connection to the DC voltage generator ( 1 ) by closing the switches (S 3 , S 4 ) and that, on the other side, it lies, together with the two diodes (D 3 , D 4 ) and the two capacitors (C 1 , C 2 ), in a second electric circuit intended for simultaneously discharging of the storage choke ( 16 ) via both capacitors (C 1 , C 2 ) and diodes (D 3 , D 4 ), the second electric circuit being made operative by opening the switches (S 3 , S 4 ).

Controlled contactless power transmission

Abstract: An inductive coupled power transmission circuit has a rotating transformer, including an AC voltage supply for feeding an AC voltage via a series capacitor into the primary winding of said rotating transformer and a load being coupled to the secondary winding of said rotating transformer. The AC voltage supply includes a line rectifier for receiving AC voltage from a power line and generating a DC voltage. This is fed into a DC/DC converter for converting the DC voltage from the line rectifier into a controlled intermediate DC voltage. An AC generator generates an AC voltage from the intermediate DC voltage and feeds this via a matching transformer into the primary winding of the rotating transformer. A measuring circuit measures voltages and/or currents within the AC voltage supply and a function generator estimates voltage and/or current values at the load based on the measured values and controls the DC/DC converter and/or the AC generator based on the estimated values.

Common-voltage compensation circuit and compensation method for use in a liquid crystal display

Abstract: A common-voltage compensation circuit functions to provide a crosstalk interference suppressing mechanism for use in a liquid crystal display having a liquid-crystal capacitor and a storage capacitor. The compensation circuit includes a buffer for receiving a preliminary common voltage, a current/voltage converter, a high-pass filter and a ripple-voltage inverter. The current/voltage converter is utilized for generating a liquid-crystal capacitor common voltage furnished to the liquid-crystal capacitor according to an output current of the buffer. The high-pass filter performs a high-pass filtering operation on the liquid-crystal capacitor common voltage for extracting a ripple voltage. The ripple-voltage inverter is employed to generate a storage capacitor common voltage furnished to the storage capacitor through performing an inverting operation on the ripple voltage based on the preliminary common voltage. The ripple voltage of the storage capacitor common voltage has a phase opposite to that of the liquid-crystal capacitor common voltage for suppressing crosstalk interference.

High sensitive RF-DC rectifier and ultra low power DC sensing circuit for waking up wireless system

Abstract: A 2.4 GHz band high-efficiency RF rectifier and high sensitive dc voltage sensing circuit is implemented. A passive RF to DC rectifier of multiplier voltage type has no current consumption. This rectifier is using native threshold voltage diode-connected NMOS transistors to avoid the power loss due to the threshold voltage. It consumes only 900nA with 1.5V supply voltage adopting ultra low power DC sensing circuit using subthreshold current reference. These block incorporates a digital demodulation logic blocks. It can recognize OOK digital information and existence of RF input signal above sensitivity level or not. A low power RF rectifier and DC sensing circuit was fabricated in 0.18um CMOS technology with native threshold voltage NMOS; This RF wake up receiver has -28dBm sensitivity at 2.4 GHz band.

A UHF voltage multiplier circuit using a threshold-voltage cancellation technique

Abstract: The operating range of passive UHF transponder systems is largely determined by the tag current consumption and the rectifier efficiency. Reading ranges of several meters have recently been reported for many state of the art RFID (Radio frequency IDentification) tags [1]. At this distance, the main issue for the rectifier design is the low amplitude of the high frequency antenna signal. Schottky diodes are often used for their low forward voltage drop and high switching speed. As an alternative to Schottky diodes, different circuit techniques for compensating the threshold voltage of standard transistor diodes have been utilized [4]. The transistor gates are biased near the threshold voltage, so that the devices effectively act as diodes with very low forward voltage drop. In the presented rectifier, a secondary diode charge pump is used to generate the DC bias for the threshold voltage compensation. The circuit is implemented in a standard CMOS technology and operates at a minimum available power of −11.3 dBm for an output DC power of 7.5 µW.

Boost-Flyback Single-Stage PFC Converter with Large DC Bus Voltage Ripple

Abstract: The life time of lighting emitting diode (LED) can reach 100,000 hours. Compared to other power supplies, the power supply for LED requires long life time in addition to high efficiency and high power factor. Electrolytic capacitor has the shortest life in switching power supplies. In order to prolong the life time of power supply, it is necessary to reduce the storage capacitance and use other kind of capacitor instead of electrolytic capacitor. In this paper the relationship between storage capacitor voltage ripple and capacitance is analyzed. The PF and DC bus voltage of the Boost-Flyback single-stage PFC converter is analyzed. When Flyback works in DCM, the DC bus voltage is independent of the load. Then the capacitance is reduced and the voltage ripple is increased, in this way, the high voltage ceramic capacitor can be used instead of electrolytic capacitor. The analysis is verified by the experiment.

High Efficiency Charge-and-Add Adjustable DC-DC Converter

Abstract: A charge-and-add DC-DC voltage converter design using a switch network that toggles between two states, either simultaneously charging a flying capacitor (one or any number) or creating a DC voltage on the output capacitor by connecting all flaying capacitors in series thus adding the input voltage to remaining voltages on flying capacitors after they were charged. A pulse generator delivers a train of pulses to toggle the switch network. Depending on the applications, the train of pulses can be continuous when a fixed unregulated voltage must be delivered, or a defined number of pulses when voltage (power) surge is to be produced. The charge-and-add converters should be capable of delivering a regulated output voltage, and in this case, pulse-width modulation (PWM) or pulse frequency modulation (PFM) can be used.

Subset selection of RFID tags using light

Abstract: Methods and apparatuses for selecting a subset of RFID tags are provided in some embodiments. These methods and apparatuses utilize the susceptibility to light by persistent nodes found in passive tags. Light can be used to intentionally reduce persistence times in a particular subset tags or even an individual tag. Then, persistent nodes can be used as a selection criterion to distinguish previously illuminated tags from non-illuminated tags. In other embodiments, a power circuit receives a RF input source and generates a direct current (DC) output voltage. The circuit includes a bias circuit to supply a gate to source bias, which is independent of the DC output voltage. The circuit further includes a voltage multiplier circuit that is coupled to the bias circuit. The voltage multiplier circuit has MOS transistors with one transistor to receive the gate to source bias.

A very high efficiency ultra-low-power 13.56MHz voltage rectifier in 150nm SOI CMOS

Abstract: This paper demonstrates the effectiveness and advantages of ULP (Ultra-Low-Power) MOS diodes vs. standard implementations of a AC-DC voltage multipler in a 150nm multiple-threshold voltage SOI CMOS technology for RFID applications. Introducing a specific design methodology, we compare two 3 stages voltage multipliers, each using one of those diodes types and driving a 1.5µA load. Both architectures use an input signal of 1V peak to peak and 13.56MHz carrier frequency. Efficiency, output voltage, temperature and current load as well as backgate voltage influences are analyzed theoretically and experimentally. The ULP implementation reaches much better output voltage and efficiency than the standard one, by 70% and a factor of 6 respectively under nominal conditions.

Neutral-point balancing of neutral-pointclamped three-level inverter with a front end switched rectifier dc source for the full modulation range

Abstract: A switched rectifier DC voltage source three-level neutral-point-clamped (NPC) converter topology is proposed here to alleviate the inverter from capacitor voltage balancing in three-level drive systems. The proposed configuration requires only one DC link with a voltage of half of that needed in a conventional NPC inverter. To obtain a rated DC link voltage, the rectifier DC source is alternately connected in parallel to one of the two series capacitors using two switches and two diodes with device voltage ratings of half the total DC bus voltage. The frequency at which the voltage source is switched is independent of the inverter and will not affect its operation since the switched voltage source in this configuration balances the capacitors automatically. The proposed configuration can also be used as a conventional two-level inverter in the lower modulation index range, thereby increasing the reliability of the drivesystem. A space-vector-based PWM scheme is used to verify this proposed topology on a laboratory system.

Evaluation circuit for capacitance and method thereof

Abstract: In an evaluation method, voltages at ends of a to-be-measured capacitor and a capacitance-adjustable circuit are switched in response to a first set of clock signals so as to adjust an integrated voltage to be a sum of the integrated voltage and a first difference voltage. Next, whether a first control event is received is judged. If not, the previous step is performed. If yes, an integration operation is performed to switch a voltage of an end of a known capacitor in order to adjust the integrated voltage to be a sum of the integrated voltage and a second difference voltage. Next, whether an integrating period ends is judged. If not, the first step is repeated. If yes, a capacitance of the to-be-measured capacitor is obtained according to the number of times that the integration operation is performed in the integrating period and a capacitance of the known capacitor.

Systems and Methods for Fast Switch Turn On Approximating Ideal Diode Function

Abstract: A switching circuit approximating the fast switching characteristics and small forward voltage drop of an ideal diode is provided. The switching circuit may include a voltage multiplier circuit, a reservoir capacitor and a pull up switch configured to be coupled to the control terminal of a semiconductor switch.

Dc-dc converter providing soft-start functions

Abstract: A DC-DC converter includes a switch circuit, a feedback circuit, an error amplifier, a soft-start circuit, and a signal modulation circuit. The switch circuit receives an input voltage and charges/discharges an inductor based on a switch control signal, thereby providing an output voltage. The feedback circuit provides a corresponding feedback voltage based on the output voltage. The error amplifier generates a comparing voltage based on the feedback voltage and a reference voltage. The soft-start circuit provides a ramp clamping voltage, which is outputted as the comparing voltage when the comparing voltage is larger than the ramp clamping voltage. The signal modulation circuit generates the switch control signal based on the comparing signal and a periodic signal.