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A led load drive circuit

A driving circuit and load current technology, which is applied in the field of LED load driving circuits, can solve problems such as poor linearity and achieve the effect of improving linearity

Active Publication Date: 2018-11-20
BCD (SHANGHAI) MICRO ELECTRONICS LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the linearity of the LED driver in the prior art is poor

Method used

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  • A led load drive circuit
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Experimental program
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Embodiment Construction

[0051] As mentioned in the background art, the LED driver in the prior art has poor linearity.

[0052] The inventor found that this is due to PWM (Pulse Width Modulation) dimming, given a pulse input, its frequency is fixed, but its pulse width is variable, which can be achieved by adjusting the pulse width The change of the average value of the output current of the LED driver. The output current value of the LED driver in this way mainly presents two current output values, that is, the stable current value at zero and stable output. As the output current value of the LED driver rises from zero to a stable current value, the control circuit of the LED driver requires a certain response time, which is usually in the range of 1 microsecond to 3 microseconds. For an LED driver with a higher input duty cycle (that is, the PWM pulse input width time of the LED driver is greater than 3 microseconds), the response time has a small effect on the output current of the LED driver, but f...

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Abstract

Disclosed in the invention is an LED load driving circuit comprising a power supply circuit, a current control circuit, a feedback circuit, and an adjusting circuit. The adjusting circuit receives a feedback signal and a driving signal so as to control first state maintaining time of the current control circuit to be identical with width inputting time of the driving signal. Therefore, a problem that the conduction state maintaining time of the LED load is less than the width inputting time of the driving signal because rising of an output current value of the LED load driving circuit from zero to a stable current value needs certain response time can be solved; and linearity of the output current of the LED load driving circuit is improved. Especially for the LED load driving circuit with the low input duty ration, linearity of the output current can be improved obviously.

Description

Technical field [0001] The present invention relates to the technical field of LED driving, in particular to an LED load driving circuit. Background technique [0002] With the development of science and technology, the applications of electronic products such as mobile phones, PADs, e-books, digital cameras, MP3, GPS, and digital photo frames are changing with each passing day, which also drives the rapid development of related electronic products. WLED (White Light Emitting Diode, white light-emitting diode) and WLED Driver (White Light Emitting Diode Driver, white light-emitting diode system driver) have a certain dimming function, so they are widely used in LCD (Liquid Crystal Display, liquid crystal display), etc. In the backlight of similar electronic products. However, the LED driver in the prior art has poor linearity. Summary of the invention [0003] In order to solve the above technical problems, an embodiment of the present invention provides an LED load driving circ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H05B37/02
CPCY02B20/40
Inventor 孙建波张旭光章莉
Owner BCD (SHANGHAI) MICRO ELECTRONICS LTD