Proportional-Integral (PI) Compensator Design of Duty-Cycle-Controlled Buck LED Driver

Kim, Marn-Go

doi:10.1109/tpel.2014.2341253

Cited by 21 publications

(16 citation statements)

References 26 publications

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“…Early developments along this line of research were reported for a boost converter by performing some approximations justified by the nature of the waveforms in this specific topology and the control used. () Simplified versions of DC‐DC power converters that are obtained by removing the storing capacitors on the output circuits have been studied in Sira‐Ramirez et al In Kim, a first‐order current mode controlled buck converter is analyzed using a root‐locus approach. The assumptions made in Packard allow to linearize the matrix exponentials, and this is applicable also to the buck LED driver studied in Kim and the first‐order buck and boost converters considered in Sira‐Ramirez et al In Min et al, the authors propose an approximate current discrete‐time model for a digitally controlled multiloop buck converter that achieves higher accuracy than the conventional averaged model at the fast timescale.…”

Section: Introductionmentioning

confidence: 99%

Nonaveraged control‐oriented modeling and relative stability analysis of DC‐DC switching converters

Al‐Turki

Aroudi

Mandal

et al. 2017

Circuit Theory & Apps

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Summary This paper presents a unified and exact nonaveraged approach to derive a frequency‐domain control‐oriented model for accurate prediction of the fast timescale dynamics and performances of switching converters with fixed frequency naturally sampled pulse width modulation and integrating feedback loop. Because the approach avoids averaging and approximations related to this process, a very good accuracy of the derived model is obtained. The main difference between the presented approach and the existing methodology for accurately predicting the behavior of switching converters is that, here, we break the feedback loop and we focus on analyzing the open‐loop gain and the effect of the system parameters on relative stability. This results in an approach much similar to control systems techniques rather than nonlinear dynamical system approaches. Consequently, the relative stability is tackled easily in the frequency domain. In particular, by treating the modulator as a gain depending on the operating point, the new model is formulated in such a way that standard control‐oriented tools such as Bode diagrams and root‐loci can be easily used. Therefore, the proposed approach gives some important issues like gain and phase margins that are highly useful in controller design. It is noticed that the crossover frequency, gain, and phase margins predicted by using the averaged model may deviate significantly from the actual values given by the proposed approach. The paper points out the sources of discrepancies and the theoretical results are validated by simulations using a circuit‐level switched model.

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Section: Introductionmentioning

confidence: 99%

Nonaveraged control‐oriented modeling and relative stability analysis of DC‐DC switching converters

Al‐Turki

Aroudi

Mandal

et al. 2017

Circuit Theory & Apps

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“…This approach is used for assessing closed‐loop stability and dynamic characteristics and compensators design. PI and PID are tuned based on this method . However, the classical controllers optimally work for a particular condition.…”

Section: Introductionmentioning

confidence: 99%

Design, analysis, and implementation of an integral terminal reduced‐order sliding mode controller for a self‐lift positive output Luo converter via Filippov's technique considering the effects of parametric resistances

Goudarzian

Khosravi

2018

Int Trans Electr Energ Syst

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Summary This paper analyzes the closed‐loop stability of a self‐lift positive output Luo converter under an integral terminal reduced‐order sliding mode controller in continuous conduction mode. This converter has a high voltage gain and can be used in power sources, telecommunications, and industrial applications. However, the dynamic model of the proposed converter is highly nonlinear and time‐varying, and also the series equivalent resistances of the diodes, switch, and inductors impact on the system function. In order to overcome these problems, a robust nonlinear controller is required to maintain the output voltage of the Luo converter at a fixed value. For this purpose, the proposed sliding mode controller is developed using Filippov's method considering the parasitic elements, load variations, and line disturbances. The controller performance is validated by simulations in PSIM software. Moreover, a laboratory prototype of the suggested control scheme has been constructed to highlight its effectiveness and feasibility. The results and comparisons demonstrate that the output voltage well tracks its reference signal under system uncertainties with a satisfactory response compared with the simple sliding mode approach.

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“…The LED is driven by an LED driver. The LED driver may be viewed as a type of dedicated DC-DC converter that functionally serves to convert the energy from a power rail (e.g., battery) to a predetermined and appropriate current for the LED load [10], [11]. Of the various LED lighting systems, it is well recognized that the design and realization of automotive LED drivers are challenging.…”

Section: Acknowledgementsmentioning

confidence: 99%

“…Nevertheless, the off-chip power transistors are often bulky and suffer from large parasitic inductance/capacitance. These shortcomings typically compromise the form factor and potentially the power-efficiency [11].…”

Section: Bus Linementioning

confidence: 99%

“…First, the average output current is imprecise. This is because the peak current control regulates only the peak current of the inductor, whilst the other parameters, such as the inductance, input voltage and output current that could affect the average output current, are not regulated [3], [11]. Second, the peak current control suffers from subharmonic oscillation when the duty cycle is larger than 0.5.…”

Section: Bus Linementioning

confidence: 99%

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Design and realization of high-performance LED drivers for automotive lighting applications

Qu¹

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This Ph.D. program pertains to the design and monolithic realization of Light Emitting Diode (LED) drivers for automotive lighting where the imperative parameters are high power-efficiency and high reliability. The grand objectives thereto are substantial improved specifications over the state-of-the-art, including power-efficiency, reliability, current driving capability, and dimming range. To achieve the said grand objectives, the specific objectives are to decouple, and hence mitigate the following two major design trade-offs that limit the performance of contemporary automotive LED drivers. The first trade-off is between high reliability and high current driving capability, and applies to both single-phase and multi-phase LED drivers. Specifically, to achieve high current driving capability, the contemporary single-phase LED driver typically suffers from low reliability arising from large current ripples. On the other hand, the multi-phase LED driver is highly advantageous to provide high current driving capability, but suffers from low reliability because of the ensuing subharmonic oscillation. To decouple this limiting trade-off, we propose the design and monolithic realization of a novel Pulse-Width-Modulation (PWM)-based dual-phase LED driver in Global Foundries (GF) 130nm BCDLite process. To achieve high current driving capability, we adopt a dual-phase power stage. To achieve high reliability, we propose an Average Current Control to eliminate the subharmonic oscillation by considering the complete inductor-current profile vis-à-vis peak current adopted/reported elsewhere. To further improve the reliability, we propose an accuracy-enhanced current sensor to ascertain good current balance in the adopted dual-phase power stage. With measurements on our prototype LED driver ICs embodying our aforesaid adoption and vi proposed circuits, we demonstrate, to the best of our knowledge, for the first time that the trade-off between high reliability and high current driving capability is decoupled, i.e., an LED driver uniquely featuring high reliability, yet high current driving capability. The second trade-off is between high power-efficiency and wide dimming range. Specifically, a wide dimming range is derived by means of high switching frequency, hence the ensuing reduced settling time of the LED current. This, however, in turn leads to a degradation of the power-efficiency due to increased switching losses. To decouple this limiting trade-off, we propose the design and monolithic realization of a novel fully soft-switched LED driver in GF 130nm BCDLite process. We achieve wide dimming range by operating at high switching frequencies, but the high switching does not compromise the power-efficiency. Using a fully soft-switching approach, the ensuing switching losses are negligible. This is achieved by a proposed Hysteretic Soft-Switching Controller (HSSC) and proposed circuitries, i.e., a voltage detector, current sensor, and a level shifter. The HSSC enables complete soft-switching, including zerovoltage switc...

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Proportional-Integral (PI) Compensator Design of Duty-Cycle-Controlled Buck LED Driver

Cited by 21 publications

References 26 publications

Nonaveraged control‐oriented modeling and relative stability analysis of DC‐DC switching converters

Nonaveraged control‐oriented modeling and relative stability analysis of DC‐DC switching converters

Design, analysis, and implementation of an integral terminal reduced‐order sliding mode controller for a self‐lift positive output Luo converter via Filippov's technique considering the effects of parametric resistances

Design and realization of high-performance LED drivers for automotive lighting applications

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