HT16561
VFD Digital Clock
Features
·
VFD display 12 hour clock function
·
4.194304MHz crystal oscillation
·
Zero adjust function
·
Integrated voltage regulator permits wide 4V to 18V
operating voltage range
·
Four level contrast control function
·
44-pin QFP package
General Description
The HT16561 provides direct drive to VFD panels to im-
plement a 12 hour clock function. In addition to obtaining
its time base from a 4.194304MHz crystal oscillation
source and in having a wide operating voltage, the de-
vice also contains a host of other features. These in-
clude a choice of adjustment modes, including single
push increment or 2Hz fast forward functions. Additional
features are provided in the form of Zero adjustment and
four levels of contrast control.
Block Diagram
C M O S
O S C O
O s c illa to r
O S C I
V
T E S T 3
T E S T 2
T E S T 1
V
D D
6 4 H z
F r e q u e n c y D iv id e r s
1 H z
1 H z
T e s t
A d ju s tm e n t
S e c o n d C o u n te r
(1 /6 0 )
a 1
D D
V
D D
b 1
M in u te C o u n te r
(1 /6 0 )
D e c o d e r
S e g m e n t
D r iv e r [P C H O p e n D r a in ]
c 1
T im e A d ju s tm e n t
A /C
S E
Z A
M S
H S
H o u r C o u n te r
(1 /1 2 )
D e c o d e r
S e g m e n t
A M /P M
g 3
b 4
c 4
A M
V
C O N T 2
C O N T 1
D IM
D D
C o n tra s t
A d ju s tm e n t
P M
V
T E S T 4
D D
Rev. 1.10
1
May 24, 2012
HOLTEK [ HOLTEK SEMICONDUCTOR INC ]
