The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform

Michael A E Andersen - One of the best experts on this subject based on the ideXlab platform.

  • ultrafast tracking power supply with fourth order Output filter and fixed frequency hysteretic control
    IEEE Transactions on Power Electronics, 2008
    Co-Authors: M C W Hoyerby, Michael A E Andersen
    Abstract:

    A practical solution is presented for the design of a non-isolated dc/dc power converter with very low Output Ripple voltage and very fast Output voltage step response. The converter is intended for use as an envelope tracking power supply for a radio frequency power amplifier (RFPA) in a TETRA enhanced data service (TEDS) base station. A simple and effective fixed-frequency hysteretic control scheme for the converter (buck with fourth-order Output filter) is developed and analyzed. The proposed approach is verified experimentally by a 500 W Output prototype, capable of delivering any voltage in the range of 10-30 V within 10 mus with 10 mVpp of Output Ripple and efficiencies in the 88%-95% range.

  • ultrafast tracking power supply with fourth order Output filter and fixed frequency hysteretic control
    IEEE Transactions on Power Electronics, 2008
    Co-Authors: M C W Hoyerby, Michael A E Andersen
    Abstract:

    A practical solution is presented for the design of a non-isolated dc/dc power converter with very low Output Ripple voltage and very fast Output voltage step response. The converter is intended for use as an envelope tracking power supply for a radio frequency power amplifier (RFPA) in a TETRA enhanced data service (TEDS) base station. A simple and effective fixed-frequency hysteretic control scheme for the converter (buck with fourth-order Output filter) is developed and analyzed. The proposed approach is verified experimentally by a 500 W Output prototype, capable of delivering any voltage in the range of 10-30 V within 10 mus with 10 mVpp of Output Ripple and efficiencies in the 88%-95% range.

  • envelope tracking power supply with fully controlled 4th order Output filter
    Applied Power Electronics Conference, 2006
    Co-Authors: M C W Hoyerby, Michael A E Andersen
    Abstract:

    This paper describes the derivation of a practical solution to designing a medium-power non-isolated DC/DC power converter with very low Output Ripple voltage and very high Output voltage slew-rate capability. The converter is intended for powering and efficiency-optimizing an RFPA (Radio Frequency Power Amplifier) in a communications system base station. A simple and effective analog control scheme for the converter (buck with 4th order Output filter) is developed, along with an accurate linear model The proposed approach is verified experimentally by a 500W Output prototype, capable of greater than 1 V//spl mu/s slew rate with 40mVpp of Output Ripple and efficiency above 90%.

M C W Hoyerby - One of the best experts on this subject based on the ideXlab platform.

  • ultrafast tracking power supply with fourth order Output filter and fixed frequency hysteretic control
    IEEE Transactions on Power Electronics, 2008
    Co-Authors: M C W Hoyerby, Michael A E Andersen
    Abstract:

    A practical solution is presented for the design of a non-isolated dc/dc power converter with very low Output Ripple voltage and very fast Output voltage step response. The converter is intended for use as an envelope tracking power supply for a radio frequency power amplifier (RFPA) in a TETRA enhanced data service (TEDS) base station. A simple and effective fixed-frequency hysteretic control scheme for the converter (buck with fourth-order Output filter) is developed and analyzed. The proposed approach is verified experimentally by a 500 W Output prototype, capable of delivering any voltage in the range of 10-30 V within 10 mus with 10 mVpp of Output Ripple and efficiencies in the 88%-95% range.

  • ultrafast tracking power supply with fourth order Output filter and fixed frequency hysteretic control
    IEEE Transactions on Power Electronics, 2008
    Co-Authors: M C W Hoyerby, Michael A E Andersen
    Abstract:

    A practical solution is presented for the design of a non-isolated dc/dc power converter with very low Output Ripple voltage and very fast Output voltage step response. The converter is intended for use as an envelope tracking power supply for a radio frequency power amplifier (RFPA) in a TETRA enhanced data service (TEDS) base station. A simple and effective fixed-frequency hysteretic control scheme for the converter (buck with fourth-order Output filter) is developed and analyzed. The proposed approach is verified experimentally by a 500 W Output prototype, capable of delivering any voltage in the range of 10-30 V within 10 mus with 10 mVpp of Output Ripple and efficiencies in the 88%-95% range.

  • envelope tracking power supply with fully controlled 4th order Output filter
    Applied Power Electronics Conference, 2006
    Co-Authors: M C W Hoyerby, Michael A E Andersen
    Abstract:

    This paper describes the derivation of a practical solution to designing a medium-power non-isolated DC/DC power converter with very low Output Ripple voltage and very high Output voltage slew-rate capability. The converter is intended for powering and efficiency-optimizing an RFPA (Radio Frequency Power Amplifier) in a communications system base station. A simple and effective analog control scheme for the converter (buck with 4th order Output filter) is developed, along with an accurate linear model The proposed approach is verified experimentally by a 500W Output prototype, capable of greater than 1 V//spl mu/s slew rate with 40mVpp of Output Ripple and efficiency above 90%.

Johann W Kolar - One of the best experts on this subject based on the ideXlab platform.

  • Output Ripple reduction of an automotive multi phase bi directional dc dc converter
    Energy Conversion Congress and Exposition, 2009
    Co-Authors: S Waffler, J Biela, Johann W Kolar
    Abstract:

    Bi-directional dc-dc converters for automotive applications typically are limited to generate only a small voltage Ripple, especially when a ultra-capacitor with a limited Ripple current capability is interfaced by the converter. Thus, to minimize the Ripple quantities and the converter volume at the same time, interleaved multi-phase dc-dc converters are utilized. However, tolerances of the buck+boost inductors of the interleaved phases generate sub-harmonics in the Ripple spectrum that are counterproductive to the advantage of Ripple reduction. A method to cancel the fundamental frequency of the voltage Ripple is proposed that is applicable to a converter consisting of three or more phases. It is shown that even for a low phase count the overall Ripple amplitude is greatly reduced, only by adjustment of the phase shift angles. Experimental results carried out with a three-phase interleaved bi-directional dc-dc converter proof the concept functionality.

Kehorng Chen - One of the best experts on this subject based on the ideXlab platform.

  • reduction of equivalent series inductor effect in delay Ripple reshaped constant on time control for buck converter with multilayer ceramic capacitors
    IEEE Transactions on Power Electronics, 2013
    Co-Authors: Weichung Chen, Chingsung Wang, Yiping Su, Kehorng Chen, Mingjhe Du
    Abstract:

    The stability of conventional constant on-time control buck converter is constrained by the time constant, which is the product of the Output capacitor and its equivalent series resistance (ESR). Specialty polymer capacitor which is mostly used as Output capacitor for such a consideration although it limits the performance of converter. On the other hand, the multilayer ceramic capacitors are widely used in commercial power management ICs due to the advantages of low cost and ESR. However, the stability often confronts with the subharmonic problem caused by small time constant. A differential-zero compensator with the noise margin enhancement (DZC-NME) technique in constant on-time control buck dc-dc converter with Output ceramic capacitor is proposed in this paper. Thus, the proposed DZC-NME technique not only eliminates the limit of large time constant but also tolerates the existence of equivalent series inductor (ESL) effect. Experiment results demonstrate small Output Ripple of 10 mV and high efficiency of 91% when ESR is smaller than 1 mΩ and large interference from ESL effect is 40 mV.

  • A dual-phase charge pump circuit with compact size
    Analog Integrated Circuits and Signal Processing, 2010
    Co-Authors: Ming-hsin Huang, Pochin Fan, Chunyu Hsieh, Kehorng Chen
    Abstract:

    In this paper, a regulated dual-phase charge pump with compact size is presented. By means of a nano-ampere switched-capacitor voltage reference (SCVR) circuit, the dual-phase charge pump regulator can reduce the quiescent current and the Output Ripple. Besides, a new power stage is proposed to define the stability of the overall system. Owing to the design of buffer stage, the charge pump regulator can extend bandwidth and increase phase margin. Thus, the transient response and driving capability can be improved. Beside, the proposed automatic body switching circuit can efficiently drive the bulk of the power p-type MOSFETs to avoid leakage and potential latch-up. This chip was fabricated by TSMC 0.35 μm, 3.3 V/5 V 2P4 M CMOS technology. The input voltage range varies from 2.9 to 4.9 V for the lithium battery and the Output voltage is regulated at 5 V. Experimental results demonstrate the charge pump can provide 50 mA maximum load current without any oscillation problems.

  • hybrid buck boost feedforward and reduced average inductor current techniques in fast line transient and high efficiency buck boost converter
    IEEE Transactions on Power Electronics, 2010
    Co-Authors: Pingching Huang, Kehorng Chen
    Abstract:

    This paper presents a buck-boost converter with high efficiency and small Output Ripple to extend the battery life of portable devices. Besides, the hybrid buck-boost feedforward (HBBFF) technique is integrated in this converter to achieve fast line response. The new control topology minimizes the switching and conduction losses at the same time even when four switches are used. Therefore, over a wide input voltage range, the proposed buck-boost converter with minimum switching loss like the buck or boost converter can reduce the conduction loss through the use of the reduced average inductor current (RAIC) technique. Moreover, the HBBFF technique minimizes the voltage variation at the Output of error amplifier. Consequently, a fast line transient response can be achieved with small dropout voltage at the Output. Especially, the converter can offer good line and load regulations to ensure a regulated Output voltage without being affected by the decreasing battery voltage. Experimental results show that the Output voltage is regulated over a wide battery lifetime, and the Output Ripple is minimized during mode transition. The peak efficiency is 97% and the transient dropout voltage can be improved substantially.

  • a dual phase charge pump with compact size
    International Conference on Electronics Circuits and Systems, 2007
    Co-Authors: Chunyu Hsieh, Pochin Fan, Kehorng Chen
    Abstract:

    In this paper, the regulated dual phase charge pump with compact size is presented. This charge pump uses the dual phase technique to reduce the Output Ripple and proposes a new power stage to define the stability of the overall system. This charge pump provides Output voltage 5V and maximum load current 50 Am with the constant frequency regulation. This design is based on TSMC 035 mum 3.3V/5V CMOS technology.

Philip K. T. Mok - One of the best experts on this subject based on the ideXlab platform.

  • a single controller four Output analog assisted digital ldo with adaptive time multiplexing control in 65 nm cmos
    European Solid-State Circuits Conference, 2019
    Co-Authors: Feng Chen, Philip K. T. Mok
    Abstract:

    This paper presents a single-controller-four-Output analog-assisted digital LDO which can regulate four Output voltage domains by sharing only one digital controller with an adaptive-time-multiplexing control scheme. The area of the digital controller is 62% smaller compared to the sum of the digital controller area of four independent LDOs. An analog-assisted loop and a push-pull auxiliary loop are used to take over the control in steady state to save quiescent power, reduce Output Ripple and enhance the response speed. A prototype is fabricated in a 65nm CMOS process. An undershoot voltage of 100mV is measured with a 47mA/20ns load step, resulting a figure-of-merit as low as 0.12ps.

  • A Constant Frequency Output-Ripple-Voltage-Based Buck Converter Without Using Large ESR Capacitor
    IEEE Transactions on Circuits and Systems II: Express Briefs, 2008
    Co-Authors: Yuan Yen Mai, Philip K. T. Mok
    Abstract:

    A constant frequency Output-Ripple-voltage based CMOS current-mode dc-dc buck converter, providing fast load transient response and reference-tracking speed, is proposed in this paper. Unlike V2 control Output-Ripple-voltage based buck converter, the proposed buck converter can achieve fast and stable load transient response without relying on ESR value of Output capacitor. In addition, the proposed converter has faster reference-tracking speed than V2 the control counterparts by about 25 times.

  • a monolithic current mode cmos dc dc converter with on chip current sensing technique
    IEEE Journal of Solid-state Circuits, 2004
    Co-Authors: Cheung Fai Lee, Philip K. T. Mok
    Abstract:

    A monolithic current-mode CMOS DC-DC converter with integrated power switches and a novel on-chip current sensor for feedback control is presented in this paper. With the proposed accurate on-chip current sensor, the sensed inductor current, combined with the internal ramp signal, can be used for current-mode DC-DC converter feedback control. In addition, no external components and no extra I/O pins are needed for the current-mode controller. The DC-DC converter has been fabricated with a standard 0.6-/spl mu/m CMOS process. The measured absolute error between the sensed signal and the inductor current is less than 4%. Experimental results show that this converter with on-chip current sensor can operate from 300 kHz to 1 MHz with supply voltage from 3 to 5.2 V, which is suitable for single-cell lithium-ion battery supply applications. The Output Ripple voltage is about 20 mV with a 10-/spl mu/F off-chip capacitor and 4.7-/spl mu/H off-chip inductor. The power efficiency is over 80% for load current from 50 to 450 mA.