HD66137 Datasheet, PDF (12/19 Pages) Hitachi Semiconductor – High-Voltage Durable 240-Channel Common Driver for Dot-Matrix STN LCD

HD66137T
V_CC
2.5V
0ms
V_{LCD, VH}
0ms
V_M
2.5V
0ms
V_EE,VL
DISPOFF
0ms
0ms
0ms
0ms
Input
signal, clock,
or data
Undefined
Initialization
(Longer than one frame)
8.1 Power on
(1) Turn on the power supply in the order of GND- V_CC, GND-VLCD (VH), and VM. VM-VEE is
generated automatically. In this case, input GND to the DISPOFF pin.
(2) The LCD level forcibely outputs the VM level by the DISPOFF function.
(3) The DISPOFF function has a priority even if input signal distortion occurs immediately after V_CC
input.
(4) Then input the predetermined signals to initialize the driver registers. In this case, assure a
period for more than one frame.
(5) Preparation for normal display is thus completed. Cancel the DISPOFF function by setting the
DISPOFF pin to V_CC. At this point, the levels of VEE (VL), VLCD (VH) and VM must have
reached the predetermined respective voltage.
8.2 Shut down
As a rule, shut down in order opposite to that used for power on.
(1) Set the DISPOFF pin to GND.
(2) At first shut off the LCD power supply GND-VLCD (VH), at same time GND-VEE (VL) get to VM.
Next shut off the VM.
(3) Set V_CC and the input signal to GND.
At this point, VEE (VL), VLCD (VH) and VM pin input must completely drop to 0 V.
Since the DISPOFF function is inactivated when the V_CC level drops to GND, the LCD output may
output a level other than VM. Therefore, an incorrect display may appear at shut down or power
on.
12