Voltages and Power_Control registers with NHD-1.8-128160EF-CSXN#-F

qfsasm

• November 08, 2018 10:07

Hi all!

We are using the NHD-1.8-128160EF-CSXN#-F in our design and we noticed a slight flickering that we did not see with the NHDev board. We believe that the flickering is caused by the different voltages of the power supply because we use 1.8 V for IOV_DD and 2.6 V for V_DD. On the NHDev board we measured 3.3 V for both.

The display is initialized with the same sequence as on page 10 in the datasheet. The commands for Power_Control are suspicious as they set the voltages for the TFT and they probably need to be adapted for our power supply. My question is if the parameter of the Power_Control should be changed when different voltages are used and if yes to which values? Also we will maybe change V_DD to 2.8 V and in the next days we will install additional capacitors to make the power supply more stable.

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  Sergio_M

  • December 01, 2018 22:07

  Hello,
  
  Is the image flickering or is it the backlight? Typically, customers tie IOVDD to VDD. We also tie IOVDD to VDD, when we build an evaluation kit, this would be the reason why you measured 3.3V for IOVDD and VDD when using the NHDev board.
  The flickering may be the result of the backlight LEDs being over driven, the current must be limited to 100mA typical. The backlight is independent of the TFT’s controller. The LED backlight is current driven and must be limited using a resistor circuit or by using a constant current source.
  
  Best Regards,

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