NT7502H-BDT Ver la hoja de datos (PDF) - Novatek Microelectronics

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NT7502H-BDT

65 X 132 RAM-Map LCD Controller / Driver

Novatek Microelectronics 

NT7502

The V0 voltage is a function of the V0 voltage regulator internal resistor ratio register and the electronic volumn register.

Setup example: When selecting Ta = 25℃ and V0 = 7V for an NT7502 model on which the temperature gradient = -0.05%℃,

using the equation A-1, the following setup is enabled.

Table. 13

Contents

Register

D5 D4 D3 D2 D1 D0

For V0 voltage regulator - - - 0 1 0

Electronic Volume

100101

# When the V0 voltage regulator internal resistors or the electronic volume function is used, it is necessary to at least set the

voltage regulator circuit and the voltage follower circuit to an operating mode using the power control set commands.

Moreover, it is necessary to provide a voltage from VOUT when the Booster circuit is OFF.

# The VR terminal is enabled only when the V0 voltage regulator internal resistors are not used (i.e. the IRS terminal = “L”).

When the V0 voltage regulator internal resistors are used (i.e. when the IRS ternimal = “H”), then the VR terminal is left open.

# Because the input impedance of the VR terminal is high, it is necessary to take into consideration short leads, shield cables,

etc. to handle noise.

The Liquid Crystal Voltage Generator Circuit

The V0 voltage is produced by a resistive voltage divider within the IC, and can be produced at the V1, V2, V3, and V4 voltage

levels required for liquid crystal driving. Moreover, when the voltage follower changes the impedance, it provides V1, V2,V3,

and V4 to the liquid crystal drive circuit. 1/9 bias or 1/7 bias for NT7502 can be selected.

High Power Mode

The power supply circuit equipped in the NT7502 chips has very low power consumption (normal mode: HPM = “H”). However

for LCDs or panels with large loads, this low-power power supply may cause display quality to degrade. When this occurs,

setting the HPM terminal to “L” (high power mode) can improve the quality of the display. We recommend that the display be

checked on actual equipment to determine whether or not to use this mode.

Moreover, if the improvement to the display is inadequate even after high power mode has been set, then it is necessary to add

a Command Sequence when Built-in Power Supply is turned OFF.

Follow the command sequence as shown below to turn off the built-in power supply after the system enters standby mode.

20

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