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<strong>ST7565</strong>* When the V5 voltage regulator internal resistors or the electronic volume function is used, it is necessary to at least set thevoltage regulator circuit and the voltage follower circuit to an operating mode using the power control set <strong>com</strong>mands.Moreover, it is necessary to provide a voltage from VOUT when the Booster circuit is OFF.* The VR terminal is enabled only when the V5 voltage regulator internal resistors are not used (i.e. the IRS terminal = “L”).When the V5 voltage regulator internal resistors are used (i.e. when the IRS terminal = “H”), then the VR terminalis left open.* Because the input impedance of the VR terminal is high, it is necessary to take into consideration short leads, shieldcables, etc. to handle noise.The LCD Voltage Generator CircuitThe V5 voltage is produced by a resistive voltage dividerwithin the IC, and can be produced at the V1, V2, V3, and V4voltage levels required for liquid crystal driving. Moreover,when the voltage follower changes the impedance, itprovides V1, V2, V3 and V4 to the liquid crystal drive circuit.High Power ModeThe power supply circuit equipped in the <strong>ST7565</strong> chips hasvery low power consumption (normal mode: HPM = “H”).However, for LCDs or panels with large loads, this low-powerpower supply may cause display quality to degrade. Whenthis occurs, setting the HPM terminal to “L” (high powermode) can improve the quality of the display. Were<strong>com</strong>mend that the display be checked on actualequipment to determine whether or not to use this mode.Moreover, if the improvement to the display is inadequateeven after high power mode has been set, then it isnecessary to add a liquid crystal drive power supplyexternally.The Internal Power Supply Shutdown Command SequenceThe sequence shown in Figure 13 is re<strong>com</strong>mended forshutting down the internal power supply, first placing thepower supply in power saver mode and then turningthe power supply OFF.Sequence Details Command address(Command, status) D7 D6 D5 D4 D3 D2 D1 D0Step1 Display OFF 1 0 1 0 1 1 1 0 Power saverStep2 Display all points ON 1 0 1 0 0 1 0 1 <strong>com</strong>mandsEnd Internal power supply OFF (<strong>com</strong>pound)Figure 13The temperature grade of the Internal Power Supply for <strong>ST7565</strong>-0A (-0.15%/°C) :10V9V8V7VTa=-40°C , V5=9.40VTa=25°C , V5=8.46VTa=85°C , V5=7.60VV5 0V-40°C -20°C 0°C 25°C 50°C 85°CTaFigure 14Ver 0.9 27/27 2001/01/11
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