HD66113T Datasheet, PDF (20/20 Pages) Hitachi Semiconductor – (120-Channel Common Driver Packaged in a Slim Tape Carrier Package)

HD66113T
LCD Driver LSI Power Supply Pin Connection
A feature of the LCD driver is the LCD drive power supply. As the number of pixel drives per LSI
increases, so does the voltage and number of outputs.
Consequently, if multi-output CMOS circuits are switched simultaneously, a wiring voltage drop may
occurs due to transient currents, and the potential between the LCD drive circuit power supply (V_LCD) and
LCD drive level power supplies (V1, V6, and V3) or GND and the LCD level power supplies (V2, V5, and
V4) may be inverted, resulting in latchup breakdown. To prevent this, it is recommended that, when
designing the LCD drive power supply and board power supply wiring, the power supply wiring be
designed as low-impedance and capacitors be inserted in the wiring between V_LCD and V1, V3, V6, and
between V2, V4, V5 and GND. In set evaluation, it is recommended that a check be carried out to confirm
that there is no inversion of the LCD drive power supply and level power supplies in the period between
when the LCD drive power supply is turned on and turned off.
Example of capacitor insertion (when V_LCD = V1 and GND = V2)
+
+
+
–
–
–
V_LCD, V1 pins
(COM, SEG)
V6 pin (COM)
+
–
V3 pin (SEG)
Electrolytic capacitor
V4 pin (SEG)
V5 pin (COM)
+
+
–
–
GND, V2 pins
(COM, SEG)
Figure 13 Example of Capacitor Insertion
Ceramic capacitor
20