Variable Off-Time Control Loop for Current-Mode Floating Buck Converters in LED Driving Applications

Anghel, Viorel; Bartholomeusz, Christopher; Vasilica, Anca; Pristavu, Gheorghe; Brezeanu, Gheorghe

doi:10.1109/jssc.2014.2320456

Cited by 42 publications

(20 citation statements)

References 13 publications

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“…The driving capabilities of the controller (V DRV - Fig. 2) are limited to a maximum of 5V only [4]. In consequence, a level shifting circuit is necessary (Level Shifter - Fig.…”

Section: Proposed Techniquementioning

confidence: 99%

“…The proposed converter architecture was implemented using our previously introduced controller fabricated in a 0.5μm 5V CMOS technology [3] [4]. The NDD05N50Z device was used as the SW transistor, the same as in simulations.…”

Section: Proof Of Conceptmentioning

confidence: 99%

“…This paper proposes a technique for enhancing the number of series connected LEDs driven by a current-mode floating buck converter with external power switch. Previously, we proposed a converter controller, implemented in a low cost CMOS technology, which adjusts the switching frequency in order to accommodate various values for the input voltage, number of LEDs and inductor [3] [4]. This controller is limited to driving a maximum of 4 series connected LEDs only, at input voltages up to 20V [4].…”

Section: Introductionmentioning

confidence: 99%

“…Previously, we proposed a converter controller, implemented in a low cost CMOS technology, which adjusts the switching frequency in order to accommodate various values for the input voltage, number of LEDs and inductor [3] [4]. This controller is limited to driving a maximum of 4 series connected LEDs only, at input voltages up to 20V [4]. In order to accommodate a larger number of series LEDs, a level shifter is included to increase driving voltage range for the switch.…”

Section: Introductionmentioning

confidence: 99%

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Application enhancement for driving large strings of LEDs

Pristavu

Vasilica

Anghel

et al. 2014

2014 International Semiconductor Conference (CAS)

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A technique for increasing the number of series connected LEDs driven by a current-mode floating buck converter is analyzed, simulated and implemented. The converter uses an external power switch, driven by a previously introduced low-cost variable frequency controller. The increase in input voltage and number of driven LEDs is achieved by the addition of a level shifter at the controller's output which enhances its capability to drive a power MOSFET switch. Measurements performed on the improved converter biasing a maximum of 16 LEDs at up to 75V emphasize a peak efficiency of 94.6%. An efficiency over 87% can be obtained in all cases.

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“…The driving capabilities of the controller (V DRV - Fig. 2) are limited to a maximum of 5V only [4]. In consequence, a level shifting circuit is necessary (Level Shifter - Fig.…”

Section: Proposed Techniquementioning

confidence: 99%

Section: Proof Of Conceptmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Application enhancement for driving large strings of LEDs

Pristavu

Vasilica

Anghel

et al. 2014

2014 International Semiconductor Conference (CAS)

Self Cite

View full text Add to dashboard Cite

show abstract

“…However, many previously-reported high-voltage (HV) LED drivers adopt an off-chip power Schottky diode as the highside power switch [5]- [10]. Since the power Schottky diode has a typical voltage drop of 1 V, these HV LED drivers suffer from considerable conduction power loss.…”

mentioning

confidence: 99%

A 26 W 97%-Efficiency Fast-Settling Dimmable LED Driver With Dual-nMOS-Sensing Based Glitch-Tolerant Synchronous Current Control for High-Brightness Solid-State Lighting Applications

Liu

Lee

2015

IEEE J. Solid-State Circuits

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This paper presents an integrated buck-type dimmable synchronous LED driver for high-brightness solid-state lighting applications. A glitch-tolerant synchronous current control (GT-SCC) scheme is proposed to regulate the average LED current. The GT-SCC enables fast settling time of the LED current upon start-up or PWM dimming condition, and provides reliable operation under high dV/dt slewing during switching transitions of the LED driver. The proposed LED driver consists of a high-speed low-power HV synchronous gate driver to enable on-chip synchronous rectification with a dual-nMOS power train under different input voltages for the conduction power loss reduction. Two on-chip senseFET peak and valley current sensors are also developed to offer low-power and reliable current sensing under high input voltages. Implemented in a 0.35 m 50 V CMOS process, the proposed LED driver supports a wide input range from 5 V to 45 V, operates up to 4 MHz with a small-value inductor of 8.2 H, handles a high PWM dimming frequency of 20 kHz with a wide duty-ratio range from 0.1 to 1, and delivers an average LED current of 700 mA for driving up to 12 series-connected HB-LEDs (with the maximum output power of 26 W). The proposed LED driver achieves a peak power efficiency of 97.2% and the current deviation 3.3% of the average LED current under different conditions. The worst-case settling time achieves 3.2 s that is at least 2.7 times improvement over state-of-the-art counterparts.Index Terms-DC-DC LED drivers, dimmable LED driver, high-brightness LED lighting, high-voltage current sensing, high-voltage gate driver, PWM dimming.

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An efficient wide input wide output CrCM flyback converter in high ‐power LED lighting

Pal

Singh

Shrivastava

2020

Int Trans Electr Energ Syst

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This paper deals with a power factor corrected (PFC) flyback converter for high-power light emitting diode lighting applications. This flyback converter is designed to operate in critical conduction mode to achieve improved power quality at universal AC mains and high efficiency with the low component count. The converter is analyzed using state-space analysis with closed-loop stability under varying input and output conditions. The PFC converter is designed and implemented with wide input and wide output variations. The performance of the prototype is also investigated for improved power quality such as power factor and harmonics distortion of AC mains current at universal AC mains of 85 to 265 V. The achieved efficiency of this converter is 92% and total harmonic distortion is less than 6% over universal AC mains for a prototype of 100 W, which are much improved results as compared to discontinuous conduction mode operation of the same converter.

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Variable Off-Time Control Loop for Current-Mode Floating Buck Converters in LED Driving Applications

Cited by 42 publications

References 13 publications

Application enhancement for driving large strings of LEDs

Application enhancement for driving large strings of LEDs

A 26 W 97%-Efficiency Fast-Settling Dimmable LED Driver With Dual-nMOS-Sensing Based Glitch-Tolerant Synchronous Current Control for High-Brightness Solid-State Lighting Applications

An efficient wide input wide output CrCM flyback converter in high ‐power LED lighting

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