NT7501 Ver la hoja de datos (PDF) - Novatek Microelectronics
Número de pieza
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NT7501 Datasheet PDF : 38 Pages
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NT7501
Display Data Latch Circuit
This circuit temporarily stores (or latches) display data (during a single common signal period) when it is output from display
RAM to LCD panel driver circuit. This latch is controlled by Display in normal/reverse Display ON/OFF and Entire display on
commands. These commands do not alter the data.
LCD Driver
This is a multiplexer circuit consisting of 100 segment outputs to generate four-level LCD panel drive signals. The LCD panel
drive voltage is generated by a specific combination of display data, a COM scan signal, and a FR signal. Figure 5 gives an
example of SEG and COM output waveform.
Oscillator Circuit
This is an oscillator having a complete built-in type CR, and its output is used as the display timing signal source or as the clock
for the voltage booster circuit of the LCD power supply.
The oscillator circuit is available in master mode only.
The oscillator signal is divided and output as a display clock at the CL pad.
Power Supply Circuit
The power supply circuit generates voltage to drive the LCD panel at low power consumption, and is available in NT7501
master mode only. The power supply circuit consists of a voltage booster, a voltage regulator and a LCD drive voltage follower.
The power supply circuit built into the NT7501 is set for a small-scale LCD panel and is inappropriate for a large-pixel panel and
a large-display-capacity LCD panel using multiple chips. As the large LCD panel has the dropped display quality due to a large
load capacity, it must use an external power source.
The power circuit is controlled by the Set Power Control command. This command sets a three-bit data in the Power Control
register to select one of eight power circuit functions. The external power supply and part of the internal power circuit functions
can be used simultaneously. The following explains how the Set Power Control command works.
[Control by Set Power Control command]
D2 turns on when the voltage booster control bit goes high, and D2 turns off when this bit goes low.
D1 turns on when the voltage regulator control bit goes high, and D1 turns off when this bit goes low.
D0 turns on when the voltage follower control bit goes high, and D0 turns off when this bit goes low.
[Practical combination examples]
Status 1: To use only the internal power supply
Status 2: To use only the voltage regulator and voltage follower
Status 3: To use only the voltage follower, input the external voltage V0
Status 4: To use only an external power supply because the internal power supply does not operate
D2 D1 D0
Voltage
booster
Voltage
regulator
Voltage
follower
External
voltage
input
1
1
1
1
ON
ON
ON
-
2
0
1
1
OFF
3
0
0
1
OFF
4
0
0
0
OFF
ON
OFF
OFF
ON
ON
OFF
VOUT
V0
V0 to V4
* The voltage booster terminals are CAP1+, CAP1-, CAP2+, CAP2- and CAP3+
* Combinations other than those shown in the above table are possible but impractical.
Voltage
booster
terminal
Used
OPEN
OPEN
OPEN
Voltage
regulator
terminal
Used
Used
OPEN
OPEN
12
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