Author Topic: Backlight current limiting resistor  (Read 4632 times)

andresmdn

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Backlight current limiting resistor
« on: October 14, 2014, 12:39:17 PM »
Are they integrated into the display? I didn't see any reference to it in the datasheet of the following display, and just wanted to be certain before completing PCB layout.

http://www.digikey.com/product-detail/en/NHD-C0216CZ-FSW-FBW-3V3/NHD-C0216CZ-FSW-FBW-3V3-ND/2059234

Michael_L

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Re: Backlight current limiting resistor
« Reply #1 on: October 16, 2014, 08:25:14 AM »
No, that display is a Chip-On-Glass LCD, and contains no electronic components except for the controller IC bonded to the glass.

andresmdn

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Re: Backlight current limiting resistor
« Reply #2 on: October 16, 2014, 10:32:16 AM »
Appreciate it Michael. Any recommended values? Suppose I can grab a unit and calculate a sample forward voltage myself, but are there any standard values that work well, independent of manufacturing tolerances?

Michael_L

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Re: Backlight current limiting resistor
« Reply #3 on: October 17, 2014, 08:18:02 AM »
It really depends on how bright you want the backlight to be.  I'd say around 100Ω.

JB

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Re: Backlight current limiting resistor
« Reply #4 on: April 27, 2015, 05:54:39 PM »
Please can you confirm that being COG does not in itself imply that a display has no current limiting resistors for the backlight? I'm looking at NHD-C12864A1Z-FS(RGB)-FBW-HT1, and it appears to show some in the "Mechanical Drawing" LED circuit, but now I'm not quite sure. Thanks.

Paul_B

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Re: Backlight current limiting resistor
« Reply #5 on: April 28, 2015, 08:20:38 AM »
Hello,

NHD-C12864A1Z-FS(RGB)-FBW-HT1 is a COG display, however the glass is attached to a pcb which contains current limiting resistors, please see page 3 in the displays datasheet.

http://www.newhavendisplay.com/specs/NHD-C12864A1Z-FSRGB-FBW-HT1.pdf




JB

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Re: Backlight current limiting resistor
« Reply #6 on: April 28, 2015, 03:54:13 PM »
Thats good, thanks.

 

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