A SIMO Parallel-String Driver IC for Dimmable LED Backlighting With Local Bus Voltage Optimization and Single Time-Shared Regulation Loop

Chen, Hai; Zhang, Yi; Ma, Dongsheng

doi:10.1109/tpel.2011.2160404

Cited by 114 publications

(45 citation statements)

References 12 publications

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“…To achieve full-range PWM dimming among the strings, a high-frequency-time-sharing (HFTS) dimming technique with timing diagram as shown in Fig. 7(b) has been proposed [15]. For HFTS dimming, the three power channels are enabled by turning on So1-So3 in a time-sharing manner over a switching period…”

Section: A Issues Of Conventional System-level Pwm Dimmingmentioning

confidence: 99%

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An Off-line Single-Inductor Multiple-Output LED Driver With High Dimming Precision and Full Dimming Range

Guo

Tan

et al. 2017

IEEE Trans. Power Electron.

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Abstract-This paper presents a single-inductor multiple-outputs (SIMO) LED driver with precise dimming and full dimming range. Based on the coordination of a string-level and a system-level dimming schemes, the proposed SIMO LED driver can overcome practical constraints of existing SIMO LED drivers such as limited dimming range and needs for high-current switches. The proposal can achieve dimming precision up to an accuracy of 1% and also full dimming range. It has the flexibility of using either phase-shift or synchronous PWM switching for dimming control. The proposed circuit and control operations have been practically verified with a 25 W off-line SIMO driven LED system. Practical evaluations of its power quality and energy efficiency are also provided.I.

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Section: A Issues Of Conventional System-level Pwm Dimmingmentioning

confidence: 99%

“…Each channel is active for a period of Ts/3 [15]. Like the LFS approach, a dimming switch can be turned on when the associated power channel is active.…”

Section: A Issues Of Conventional System-level Pwm Dimmingmentioning

confidence: 99%

An Off-line Single-Inductor Multiple-Output LED Driver With High Dimming Precision and Full Dimming Range

Guo

Tan

et al. 2017

IEEE Trans. Power Electron.

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“…An improved uniform dimming with fast response time for an eight-channel LED driver was designed and analyzed for backlighting [6]. A single time-shared control loop-based SIMO dimmable LED driver with uniform current distribution was discussed [4]. A digitally controlled boost LED driver for low power display backlighting was exhibited [18].…”

Section: Related Workmentioning

confidence: 99%

A novel single-inductor eight-channel light-emitting diode driver for low power display backlight applications

Parthasarathy¹,

Nagarajan²

2018

Turk J Elec Eng & Comp Sci

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A novel decoder-based single-inductor eight-channel light-emitting diode (LED) driver circuit for low power display backlight applications has been proposed. Uniform brightness in the display provides better picture clarity, which can be achieved by providing uniform DC currents to all channels in the backlight arrangement. Existing systems use individual current regulators for each channel, which fails to provide uniform current to individual channels. Instead, uniform current is provided to all eight channels in the proposed system as the same current is distributed to all channels using time-multiplexing by a 3 × 8 decoder and a 3-bit binary up-counter. A digital pulse width modulator is used in the existing system, which has unwanted switching activities and electromagnetic interference (EMI). Unwanted switching activities and EMI are completely eliminated in the proposed system by applying a novel switching technique.The proposed LED driver is designed and implemented using the 180-nm CMOS process. Each channel is designed to conduct 300 mA of current through it when the supply is 12 V. The proposed LED driver consumes total power of 8.746W at 27• C while the peak power efficiency is 96.26%. The minimum current balancing error of the proposed LED driver is 0.019%, whereas it is 0.12% for the existing system. The existing method exhibits an average current balancing error of 2.04% whereas the proposed technique exhibits 1.33% as the average current balancing error, which is 34.82% less than the existing system.

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“…The most effective way to do this is by using a much lower-power LED to implement the surface source. To date, effective control strategies for balancing LED currents only include the linear balancing way and the digital pulse balancing way, such as is shown in Figure 1 [1][2][3][4][5][6][7][8][9][10]; in which Figure 1a,b demonstrate linear balancing ways and Figure 1c illustrates the digital pulse balancing way. In Figure 1a, all LED strings are supplied by a constant voltage source (CVS).…”

Section: Introductionmentioning

confidence: 99%

LED Current Balance Using a Variable Voltage Regulator with Low Dropout vDS Control

Hsieh

Wang

2017

Applied Sciences

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A cost-effective light-emitting diode (LED) current balance strategy using a variable voltage regulator (VVR) with low dropout v DS control is proposed. This can regulate the multiple metal-oxide-semiconductor field-effect transistors (MOSFETs) of the linear current regulators (LCR), maintaining low dropout v DS on the flat v GS -characteristic curves and making all drain currents almost the same. Simple group LCRs respectively loaded with a string LED are employed to implement the theme. The voltage VV dc from a VVR is synthesized by a string LED voltage Nv D , source voltage v R , and a specified low dropout v DS = V Q . The VV dc updates instantly, through the control loop of the master LCR, which means that all slave MOSFETs have almost the same biases on their flat v GS -characteristic curves. This leads to all of the string LED currents being equal to each other, producing an almost even luminance. An experimental setup with microchip control is built to verify the estimations. Experimental results show that the luminance of all of the string LEDs are almost equal to one another, with a maximum deviation below 1% during a wide dimming range, while keeping all v DS of the MOSFETs at a low dropout voltage, as expected.

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A SIMO Parallel-String Driver IC for Dimmable LED Backlighting With Local Bus Voltage Optimization and Single Time-Shared Regulation Loop

Cited by 114 publications

References 12 publications

An Off-line Single-Inductor Multiple-Output LED Driver With High Dimming Precision and Full Dimming Range

An Off-line Single-Inductor Multiple-Output LED Driver With High Dimming Precision and Full Dimming Range

A novel single-inductor eight-channel light-emitting diode driver for low power display backlight applications

LED Current Balance Using a Variable Voltage Regulator with Low Dropout vDS Control

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