Wide-band suppression of photon-number fluctuations in a high-speed light-emitting diode driven by a constant-current source

1998 ◽  
Vol 72 (3) ◽  
pp. 284-286 ◽  
Author(s):  
M. Kobayashi ◽  
M. Kohno ◽  
Y. Kadoya ◽  
M. Yamanishi ◽  
J. Abe ◽  
...  
Keyword(s):  
High Speed ◽  
Light Emitting Diode ◽  
Photon Number ◽  
Current Source ◽  
Wide Band ◽  
Constant Current ◽  
Constant Current Source ◽  
Light Emitting

LIGHT EMITTING DIODE DRIVERS AND CONTROL

2011 ◽  
Vol 20 (02) ◽  
pp. 267-286
Author(s):  
STEVE WINDER
Keyword(s):  
Light Emitting Diode ◽  
Current Source ◽  
Constant Current ◽  
Constant Current Source ◽  
Basic Principles ◽  
Light Emitting ◽  
Control Techniques ◽  
Switching Regulator ◽  
Step Down ◽  
And Control

This paper outlines the various driving and control techniques for Light Emitting Diodes (LEDs). LEDs should be driven from a constant current source. High power LEDs are usually driven from a switching regulator, for reasons of efficiency. The types of drivers described include Buck (step-down), Boost (step-up) and Buck-Boost (step-up or step-down). Isolated drivers and Power Factor Correction (PFC) circuits are also described. This brief paper can only describe the basic outline of these circuits, but this should be sufficient to allow the basic principles to be understood.

Observation of the collective Coulomb blockade effect in a constant-current-driven high-speed light-emitting diode

1997 ◽  
Vol 14 (6) ◽  
pp. 1295 ◽  
Author(s):  
Jun’ichi Abe ◽  
Gen Shinozaki ◽  
Takuya Hirano ◽  
Takahiro Kuga ◽  
Masamichi Yamanishi
Keyword(s):  
Coulomb Blockade ◽  
High Speed ◽  
Light Emitting Diode ◽  
Constant Current ◽  
Light Emitting

Design and Study on Power Supply for Giant Magnetostrictive Accurate-Motion Actuator

2008 ◽  
Vol 392-394 ◽  
pp. 787-792
Author(s):  
M. Wu ◽  
Xi Lin Zhu
Keyword(s):  
High Speed ◽  
High Performance ◽  
Design Method ◽  
Current Source ◽  
Fast Response ◽  
Low Noise ◽  
Constant Current ◽  
Loop Current ◽  
Constant Current Source ◽  
Wide Range

The architecture and operation theory of Giant Magnetostrictive Accurate-motion Actuator have been introduced. After analysing the driving characteristic of giant magnetostrictive material and requirement of driving power, a design method of wide range and high precision NC constant-current source has been put out. The output circuit is composed of serial 12-bit DACs Max531, low-noise high-speed precision operational amplifiers OP27 and driving circuit. It provides current from 0 to 2.048A with 0.5mA step value. Two fully differential input channels 16-bit, sigma-delta ADCs AD7705 collects output current in feedback loop. Current ripple is controlled under 0.25mA through using homemade high-performance linear power. The result shows that the driving power with characteristic of high stability and fast response meets the needs of driving of Giant Magnetostrictive Accurate-motion.

scholarly journals Wideband squeezing in photon number fluctuations from a high-speed light-emitting diode

2000 ◽  
Vol 7 (6) ◽  
pp. 215 ◽  
Author(s):  
Jun'ichi Abe ◽  
Takahiro Kuga ◽  
Takuya Hirano ◽  
Masahide Kobayashi ◽  
Masamichi Yamanishi
Keyword(s):  
High Speed ◽  
Light Emitting Diode ◽  
Photon Number ◽  
Light Emitting

scholarly journals Illumination Adaptation in a Multi-Wavelength Opto-Electronic Patch Sensor

Sensors ◽  
2020 ◽  
Vol 20 (17) ◽  
pp. 4734 ◽  
Author(s):  
Liangwen Yan ◽  
Yue Yu ◽  
Sijung Hu ◽  
David Mulvaney ◽  
Panagiotis Blanos ◽  
...  
Keyword(s):  
Rapid Determination ◽  
Current Source ◽  
Constant Current ◽  
Blood Oxygen Saturation ◽  
Led Driver ◽  
Constant Current Source ◽  
Light Emitting ◽  
Multi Wavelength ◽  
The Individual ◽  
Microcontroller Unit

In capturing high-quality photoplethysmographic signals, it is crucial to ensure that appropriate illumination intensities are used. The purpose of the study was to deliver controlled illumination intensities for a multi-wavelength opto-electronic patch sensor that has four separate arrays each consisting of four light-emitting diodes (LEDs), the wavelength of the light generated by each array being different. The study achieved the following: (1) a linear constant current source LED driver incorporating series negative feedback using an integrated operational amplifier circuit; (2) the fitting of a linear regression equation to provide rapid determination of the LEDs driver voltage; and (3) an algorithm for the automatic adjustment of the output voltage to ensure suitable LED illumination. The data from a single centrally-located photo detector, which is capable of capturing all four channels of back-light in a time-multiplexed manner, were used to monitor heart rate and blood oxygen saturation. This paper provides circuitry for driving the LEDs and describes an adaptive algorithm implemented on a microcontroller unit that monitors the quality of the photo detector signals received in order to control each of the individual currents being supplied to the LED arrays. The study demonstrated that the operation of the new circuitry in its ability to adapt LED illumination to the strength of the signal received and the performance of the adaptive system was compared with that of a non-adaptive approach.

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