71m6511h-igtr Maxim Integrated Products, Inc., 71m6511h-igtr Datasheet - Page 79

• Manufacturer Part Number: 71m6511h-igtr
• Description: Single-phase Energy Meter Ic
• Manufacturer: Maxim Integrated Products, Inc.

The 71M6511 has a LCD controller on-chip capable of controlling static or multiplexed LCDs. Figure 33 shows the basic
connection for a LCD.
Figure 34 shows how 5V LCDs can be operated even when a 5V supply is not available. Setting the I/O RAM register
LCD_BSTEN to 1 starts the on-chip boost circuitry that will output an AC frequency on the VDRV pin. Using a small coupling
capacitor, two general-purpose diodes and a reservoir capacitor, a 5VDC voltage is generated which can be fed back into the
VLCD pin of the 71M6511. The LCD drivers are enabled with the I/O register LCD_ON; I/O register LCD_FS is used to adjust
contrast, and LCD_MODE selects the operation mode (LCD type).
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LCD type
LCD type
LCD_BSTEN
LCD_BSTEN
Contrast
Contrast
ON/OFF
ON/OFF
V3P3
V3P3
LCD_MODE
LCD_MODE
71M6511
71M6511
© 2005-2007 TERIDIAN Semiconductor Corporation
LCD_EN
LCD_EN
LCD_FS
LCD_FS
Figure 34: LCD Boost Circuit
Figure 33: Connecting LCDs
71M6511
71M6511
Connecting LCDs
VLCD
VLCD
VDRV
VDRV
Single-Phase Energy Meter IC
LCD
LCD
V3P3
V3P3
71M6511/71M6511H
segments
segments
commons
commons
5VDC
5VDC
DATA SHEET
commons
commons
5V LCD
5V LCD
segments
segments
AUGUST 2007
V2.6