Newhaven Display Forum

Newhaven Products => Character LCDs => Topic started by: oscargomezf on September 02, 2016, 03:07:04 AM

Title: LED+ and VDD pins from different LCD character models.
Post by: oscargomezf on September 02, 2016, 03:07:04 AM
Hi,

I'm working on a new project and I would like to choose one of them, but I've got some doubts about the power supply in the pins Vdd and LED+.

On one hand, the model NHD-0216K1Z-NSB-FBW-L is good for my project, but I've found this one with flat flexible cable NHD-02161Z-FSY-YBW-C which fits better, but I can't understand something about the datasheet.

The specifications of the model NHD-0216K1Z-NSB-FBW-L are:  VDD=LED+=+5.0V

But the specification fo the model with flat flexible cable NHD-02161Z-FSY-YBW-C are: VDD=+5.0V and LED+=+4.0V So I'm going to need another buck to generate +4.0V.

I think this is a bit strange. Could anyone confirm that this is right?

Best regards.
Title: Re: LED+ and VDD pins from different LCD character models.
Post by: Ted_M on September 02, 2016, 12:25:33 PM
The NHD-0216K1Z-NSB-FBW-L display already includes a current limiting resistor on it's PCB and therefore will run off the same +5v supply.

The difference with the LED voltage requirements of the NHD-02161Z-FSY-YBW-C display is that it does not include a current limiting resistor on it's PCB for the backlight.
To supply 5V to the backlight you could use a series current limiting resistor instead of a buck circuit. This display typically uses 20mA at 4.0V and to supply this I would recommend using a 50Ω resistor.
Title: Re: LED+ and VDD pins from different LCD character models.
Post by: oscargomezf on September 05, 2016, 12:54:34 AM
Ok, Understood.
Thank you very much.