Showing papers on "Low-dropout regulator published in 2003"

A capacitor-free CMOS low-dropout regulator with damping-factor-control frequency compensation

Abstract: A 1.5-V 100-mA capacitor-free CMOS low-dropout regulator (LDO) for system-on-chip applications to reduce board space and external pins is presented. By utilizing damping-factor-control frequency compensation on the advanced LDO structure, the proposed LDO provides high stability, as well as fast line and load transient responses, even in capacitor-free operation. The proposed LDO has been implemented in a commercial 0.6-/spl mu/m CMOS technology, and the active chip area is 568 /spl mu/m/spl times/541 /spl mu/m. The total error of the output voltage due to line and load variations is less than /spl plusmn/0.25%, and the temperature coefficient is 38 ppm//spl deg/C. Moreover, the output voltage can recover within 2 /spl mu/s for full load-current changes. The power-supply rejection ratio at 1 MHz is -30 dB, and the output noise spectral densities at 100 Hz and 100 kHz are 1.8 and 0.38 /spl mu/V//spl radic/Hz, respectively.

Positive output super-lift converters

Abstract: The voltage lift technique has been successfully employed in design of DC/DC converters, e.g., four series Luo converters. However, the output voltage increases in arithmetic progression. This paper introduces a novel approach-super-lift technique that implements the output voltage increasing in geometric progression. It effectively enhances the voltage transfer gain in power law.

Design considerations for VRM transient response based on the output impedance

Abstract: This paper discusses the transient response of voltage regulator modules (VRMs) based on the small-signal models. The concept of constant resistive output impedance design for the VRM is proposed, and its limitations in applications are analyzed. The impacts of the output filter and the feedback control bandwidth show that there is an optimal design that allows the VRM to achieve fast transient response, small size and good efficiency. Simulations and experimental results prove the theoretical analysis.

Low dropout voltage regulator with non-miller frequency compensation

Abstract: A low dropout voltage regulator circuit with non-Miller frequency compensation is provided. The circuit includes an input voltage terminal; an output voltage terminal; an error amplifier having a first input coupled to a reference voltage; a voltage follower coupled to an output of the error amplifier; a pass device; and a feedback network. An input terminal of the pass device is coupled to the input voltage terminal. A control terminal of the pass device is coupled to an output of the voltage follower. An output terminal of the pass device is the output voltage terminal. The feedback network includes two resistors in series between the output voltage terminal and ground. A node between the resistors is coupled to a second input of the error amplifier. A frequency compensation capacitor also is coupled between the output voltage terminal and the node.

Common duty ratio control of input series connected modular DC-DC converters with active input voltage and load current sharing

Abstract: In this paper, active input voltage and load current sharing of DC-DC converter modules connected in series at the input and parallel at the output employing a novel common duty ratio control concept, is proposed. An appropriate analysis and experimental results are presented to verify the proposed concepts.

Method of regulating the supply voltage of a load and related voltage regulator

Abstract: The method is for regulating the supply voltage of a load via a switching voltage regulator having an inductor driven by at least a power switch for delivering current to an output capacitor having a certain parasitic series resistance, connected between the output node of the regulator and ground and to an electric load eventually connected in parallel to the output capacitor The method includes establishing a reference voltage, generating a comparison signal as the sum of a first voltage signal proportional to the current circulating in the inductor and of a second voltage signal depending on the difference between the output voltage and the reference voltage and on the first voltage signal The comparison signal is compared with at least a threshold for generating a logic signal that switches between an active state and an inactive state and viceversa each time that the threshold is crossed, and the turn on or the turn off of the switch is controlled as a function of the state of the logic signal

Digital loop for regulating dc/dc converter with segmented switching

Abstract: A power control circuit is provided containing a switch array, which includes segmented switches, a flying capacitor, an output voltage terminal, a feedback loop, and a digital voltage regulator block. The digital voltage regulator block includes an A/D converter, an encoder, an add-subtractor, and a gate logic. These power control circuits do not include pass transistors. A method is also provided, where the charge pumps of the power control circuit are operated in two-phase cycles including a charging phase and a pumping phase. The power control circuit is controlled in both of these phases, thereby reducing the ripple of the output voltage.

Optimal design of the active droop control method for the transient response

Abstract: Use of the active droop control method is a popular way to achieve adaptive voltage position (AVP) for the voltage regulator (VR). This paper discusses the small-signal model of the active droop control method, which is shown to be a two-loop feedback control system. The compensator design impacts both the current and voltage loops, making the design complicated. An optimal design method is proposed in order to achieve equal crossover frequencies for the two loops so that constant output impedance is realized in the VR. Simulation and experimental results prove the good VR transient response and high efficiency.

Systems and methods for charging a battery

Abstract: A charger includes an alternating current (AC) voltage booster coupled to an input voltage; and a DC regulator coupled to the AC voltage booster to charge a battery. An energy supply system includes a solar panel to generate an input voltage from solar energy; a battery; an alternating current (AC) voltage booster coupled to the solar panel to receive the input voltage; and a DC regulator coupled to the AC voltage booster to charge the battery.

Voltage control for wind generators

Abstract: A wind turbine generator control system includes relatively fast regulation of voltage near the individual generators with relatively slower overall reactive power regulation at a substation or wind farm level. The setpoint of the relatively fast voltage regulator is adjusted by the relatively slow reactive power regulator. The fast voltage regulation can be at the generator terminals or at a synthesized remote point.

Negative output super-lift converters

Abstract: The voltage lift technique has been successfully employed in design of DC/DC converters, e.g., four series Luo-converters. However, the output voltage increases in arithmetic progression. Negative output super lift technique in this paper implements the output voltage increasing in geometric progression. It effectively enhances the voltage transfer gain in power-law.

Biasing system and method for low voltage DC—DC converters with built-in N-FETs

Abstract: A gate drive supply circuit generating a high-level supply voltage and a low-level supply voltage for driving N-type high-side and low-side power MOSFETs in a multiple-output, low-voltage DC-DC converter integrated circuit. The gate drive supply circuit includes a boost regulator for generating the low-level supply voltage and a charge pump doubler for generating the high-level supply voltage. Both the high-level supply voltage and the low-level supply voltage are distributed to one or more regulators, including but not limited to buck or boost type regulators.

Digital controller for DC-DC switching converters

Abstract: A voltage regulator includes an input terminal adapted for being coupled to an input voltage and an output terminal adapted for being coupled to a load. The voltage regulator includes a first switch adapted for selectively coupling to the input terminal and to the output terminal, a current sensor for measuring an output current flowing towards the output terminal, a voltage sensor for measuring the output voltage from the output terminal, and a digital controller which drives the first switch. The controller closes the first switch when the error voltage is less than a first preset value of voltage and opens the first switch when the output current is greater than a first preset value of current.

Ultra-low quiescent current low dropout (LDO) voltage regulator with dynamic bias and bandwidth

Abstract: An LDO regulator automatically switches from the SLEEP mode to the ON mode without the need for an externally generated control signal. The LDO regulator utilizes a pair of drive amplifiers to drive a SLEEP mode pass transistor and a normal ON mode pass transistor, respectively. The regulator also has a circuit for adjusting the bias applied to the amplifiers for each mode of operation.

Apparatus and method for a voltage booster with improved voltage regulator efficiency

Abstract: A power management system includes a voltage booster in combination with a voltage regulator to provide a regulated output voltage. The voltage provided to the voltage regulator is used to selectively enable/disable the doubling functionality of the voltage booster to increase power conversion efficiency.

Two-stage 48 V power pod exploration for 64-bit microprocessor

Abstract: In this paper, a new two-stage structure is proposed. For the first stage, a concept of energy transfer by the leakage inductor combined with the resonance is used to achieve a simple, high efficiency isolation stage. Application of this concept leads to the discovery of a family of simple, high efficiency DC/DC transformers. In order to achieve optimal system performance, the intermediate bus voltage is also investigated. Finally, The experimental results are provided.

PWM control circuit for the post-adjustment of multi-output switching power supplies

Abstract: A multi-output switching power supply may include a PWM regulator circuit arranged in cascade upstream of each output to receive, as an input, a square wave voltage signal with a predetermined duty cycle The regulator circuit may include an auxiliary switching device for modulating the duty cycle of the input signal to supply, as an output, a regulated direct current voltage A control circuit for the PWM regulator circuit may include a detector circuit for detecting the trailing edges of the voltage signal input to the regulator circuit which emits a pulse coinciding with each of the trailing edges The control circuit may also include a ramp signal generator that is controlled by the emitted pulses The ramp signal generator may be connected to the non-inverting input of a comparator having an inverting input for receiving a signal indicative of the error in the regulator output voltage

Low noise switching voltage regulator

Abstract: A low-noise switching voltage regulator for supplying a voltage to a radio frequency (RF) power amplifier is disclosed. In one embodiment, the invention can be conceptualized as a power amplifier supply circuit, comprising a pair of oppositely polarized semiconductor switches, and a data formatter configured to supply a data stream having a voltage transition on at least every other bit to each of the pair of oppositely polarized semiconductor switches.

Method and apparatus for maintaining an approximate constant current output characteristic in a switched mode power supply

Abstract: A regulator circuit maintaining an approximate constant current output characteristic. In one aspect, a disclosed regulator controls a switch that has a current limit threshold. A supply terminal and feedback terminal of the regulator are connected together as a control terminal such that a shunt regulator current is the control terminal current in excess of the internal supply current consumed by the regulator. The current limit threshold of the switch is changed as a function of the shunt regulator current. In another aspect, a control input of the regulator circuit receives a current that is the sum of the internal supply current consumed by the regulator circuit and a feedback current. The feedback current is a fraction of the consumption current of the regulator circuit and the current limit threshold of the switch is changed as a function of the feedback current.

Method and circuitry for controlling supply voltage in a data processing system

Abstract: Supply voltages within a data processing system may be controlled by a voltage control module which can provide digital signals to a power management unit to cause changes in supply voltages without software intervention. For example, in one embodiment, a voltage control signal and a standby signal may be provided to control the supply voltages output by a voltage regulator within the power management unit. In one embodiment having multiple processors, a voltage control signal and a standby signal corresponding to each processor may be provided to the power management unit which has a voltage regulator supplying an independently controlled supply voltage to each processor. Alternatively, a voltage regulator, a voltage control signal, and a standby signal may be shared by multiple processors, where the voltage control module may ensure that the supply voltage is changed only when the change is appropriate for all processors sharing the same voltage regulator.

Low dropout voltage regulator using a depletion pass transistor

Abstract: A linear low dropout voltage regulator is described that makes use of a depletion mode NMOS pass transistor and of a PMOS transistor in series to the NMOS transistor and connected to its drain. The depletion NMOS transistor assures low dropout operations, while the series PMOS transistor allows the current regulation even under the condition of shorted load. The same PMOS transistor may be used to disable the current in the load without generating a negative voltage at the gate of the depletion pass transistor. This regulator is inherently stable without the need for an output capacitor in parallel to the load.

Dual input ac/dc to programmable dc output converter

Abstract: A power converter capable of receiving either an AC input voltage or a DC input voltage and generating a programmable DC output voltage. The converter comprises a first circuit that converts an AC input voltage to a predetermined DC first output voltage, and a second circuit that converts a DC input voltage to a predetermined second DC output voltage. The converter also comprise a third circuit which is adapted to receive the first and second DC voltages from first and second circuits to generate a selectable output DC voltage. In selected embodiments, the first and second DC output voltages provided by the first and second circuits, respectively, are generally the same value and are coupled to a common node that feeds the input terminal of the third circuit. Moreover, the third circuit is adapted to provide a selectable output DC voltage which may be set higher or lower than its DC input voltage. The third circuit may also be adapted to couple a set of removable programming keys that provide for a different associated DC output voltage. The programming key comprises a resistor, which may provide for a variety of functions, such as current-limiting, over-voltage protection, output voltage programming, and wrong-tip circuit protection.

Constant ON-time controller for a buck converter

Abstract: A constant ON-time controller for a buck converter utilizes dual symmetrical ramps. The ramps may be generated artificially or by sensing the voltage across a sense resistor in the output. The ramp may also be generated by sensing the voltage across the “ON” resistance of the low side FET in the switching regulator. A modified output voltage has one of the ramps superimposed and a modified reference voltage has the other ramps superimposed. The modified output voltage and the modified reference voltage are compared to determine when to start the ON-time of the buck converter. The dual ramps reduce, noise susceptibility. The ON-time is stopped in response to charging a capacitor with the regulator input voltage. An offset may also be generated representing the difference between the average output voltage and the reference voltage. The offset is used to generate a modified reference to compensate for the offset.

LED driver with increased efficiency

Abstract: One of the several driver topologies provided by the present invention combines a charge pump, a DC/DC converter and a current source. The charge pump is unregulated and, as a result, has a high efficiency. The efficiency of the DC/DC converter is also high and the combination yields an overall efficiency of potentially more than 92%. A second topology combines a voltage regulator and a current source. The voltage regulator is connected to monitor the forward voltage of a driven LED and uses the forward voltage as a reference to produce an adaptive regulated voltage. This allows the voltage regulator to react to changes in the LED forward voltage by setting the regulated voltage to the lowest appropriate level. This second topology may also be configured to disable the voltage regulator when battery voltage exceeds a predetermined level.

Design of a 5 kW high output voltage series-parallel resonant DC-DC converter

Abstract: This work presents a comprehensive procedure for designing a high output voltage series-parallel resonant DC-DC converter. The system output voltage control is by a combination of duty-cycle and switching frequency variation, where soft-switching is preserved over the entire operating range. The basic principle of operation of the converter is described and an analytical model is established which does provide a basis for the numerical calculation of the stresses on the power components. Furthermore, a control strategy for minimizing the no-load conduction losses is proposed and the transient behavior in case of load steps including output short-circuit is discussed based on digital simulations.

Compensation for low drop out voltage regulator

Abstract: A voltage regulator apparatus includes an error amplifier that amplifies a voltage difference between a reference and a sampled output voltage of the voltage regulator apparatus. A driver amplifier has an input that is responsive to the amplified voltage difference to produce a gate driving voltage at its output. An output transistor having a drain, a gate, and a source is also included. The gate is responsive to the gate driving voltage to produce a regulated output voltage at the source. To stabilize the voltage regulator apparatus, a Miller compensation capacitor is provided to feed a sample of the regulated output voltage back to the input of the driver amplifier; and additionally, an Ahuja compensation circuit is provided to feed back a portion of the regulated output voltage back to the input of the driver amplifier.

Power conversion apparatus and power conversion system having the power conversion apparatus

Abstract: A power conversion apparatus of this invention includes a power switching device, a voltage sensor, a current sensor, and a device controller connected to the switching device, the voltage sensor, and the current sensor. The voltage sensor detects an output voltage of the switching device to output a first signal depending on the output voltage, and the current sensor detects an output current of the switching device to output a second signal depending on the output current. The device controller includes a driver connected to the switching device and a correcter connected to the driver, the voltage sensor and the current sensor. The driver outputs a third drive signal to the switching device. The correcter monitors a switching loss and a surge voltage by using the first and second signals, and corrects the third signal depending on values of the switching loss and the surge voltage.

Two-step ripple-free multi-phase buck converter and method thereof

Abstract: A two-step ripple-free multi-phase buck converter and method thereof comprises a first-stage voltage regulator to convert an input voltage to an intermediate voltage and a second-stage voltage regulator with a phase number not less than two to further convert the intermediate voltage to an output voltage by a split phase control, in which the ratio of the intermediate voltage to the output voltage is intended to the phase number such that the steady state output current of the converter approaches to be ripple-free, and hence the drivers and MOSFETs for the second-stage voltage regulator are lower cost, the efficiency of the second-stage voltage regulator is improved, and a higher slew rate current is obtained for transient driving capabilities.

Ultra-low quiescent current low dropout (LDO) voltage regulator with dynamic bias and bandwidth

Abstract: An LDO regulator automatically switches from the SLEEP mode to the ON mode without the need for an externally generated control signal. The LDO regulator utilizes a pair of drive amplifiers to drive a SLEEP mode pass transistor and a normal ON mode pass transistor, respectively. The regulator also has a circuit for adjusting the bias applied to the amplifiers for each mode of operation.

Charge-recycling voltage domains for energy-efficient low-voltage operation of digital CMOS circuits

Abstract: We describe an energy-efficient means to achieve on-chip dc-dc conversion for dynamic energy-performance trade-offs in digital circuits. The approach uses balanced voltage islands running at fractions of the supply voltage. Charge "discarded" by one domain is "recycled" to supply energy for another. When the domains are ideally balanced, all the energy dissipated by electrons in "dropping" to lower potentials is used for active computation. We describe the design of an active on-chip voltage regulation scheme to provide controlled dc-dc conversion with this technique.