HT16562 1/2 Duty VFD Digital Clock

HT16562
1/2 Duty VFD Digital Clock
Features
· VFD display 12 hour clock function
· Integrated voltage regulator permits wide 4V to 18V
operating voltage range
· Directly drive VFD panels at 1/2 Duty cycle
· 4.194304MHz crystal oscillation
· Four levels of illumination control function
· Zero adjust function
· 30-pin SSOP package
General Description
The HT16562 provides direct drive to VFD panels to implement a 12 hour clock function. Obtaining its time
base from a 4.194304MHz crystal oscillation source
and in having a wide operating voltage due to its internal
voltage regulator, the device also contains a host of
other features. These include a choice of adjustment
modes, including single push increment or 2Hz fast forward functions. Additional features are provided in the
form of Blank control, Zero adjustment and four levels of
illumination control.
Block Diagram
V C C
V S S
V
V
D D
V
D D
V o lta g e R e g u la to r C ir c u it
V D D
D D
1 a , 3 a
1 b ,3 b
H o u r C o u n te r
V
H S
V
V
D D
D D
1 c , 3 c
M in u te C o u n te r
S e g m e n t
D e c o d e r
S e c o n d C o u n te r
S e g m e n t O u tp u t D r iv e r
Z A
D D
T im e A d ju s tm e n t
A /C
1 d , 3 d
1 e , 3 e
1 f, 3 f
1 g , 3 g
2 a , 2 d
2 b , 4 b , 4 c
2 c , c o l*
2 c , c o l'*
M S
2 e
2 f
B L A N K
2 g
C o lo n
F re q u e n c y
T E S T
6 4 H z
X T
O s c illa to r
G R 1
F r e q u e n c y D r iv e r C ir c u it
G r id
D e c o d e r
D IM 1
B r ig h tn e s s A d ju s tm e n t
D IM 2
G r id O u tp u t D r iv e r
X T
G R 2
Note: ²*² col indicates a blink colon and col¢ indicates a continuous light colon.
Rev. 1.30
1
May 24, 2012
HT16562
Pin Assignment
G R 2
1
3 0
G R 1
V C C
2
2 9
2 a , 2 d
V D D
3
2 8
2 b , 4 b , 4 c
6 4 H z
4
2 7
2 f
T E S T
5
2 6
B L A N K
6
D IM 1
2 5
7
2 4
D IM 2
8
2 3
X T
9
2 2
X T
1 0
G R 1
1
3 0
G R 2
2 a , 2 d
2
2 9
V C C
2 b , 4 b , 4 c
3
2 8
V D D
2 f
4
2 7
6 4 H z
2 c , c o l*
2 c , c o l*
5
2 6
T E S T
2 c , c o l'*
2 c , c o l'*
6
B L A N K
2 e
2 e
2 5
7
2 4
D IM 1
2 g
2 g
8
2 3
1 d , 3 d
9
2 2
D IM 2
1 d , 3 d
2 1
1 e , 3 e
1 e , 3 e
1 0
X T
1 c , 3 c
1 1
2 1
X T
V S S
1 1
2 0
1 c , 3 c
2 0
V S S
A /C
1 2
1 9
1 g , 3 g
1 g , 3 g
1 2
1 9
A /C
Z A
1 3
1 8
1 f, 3 f
1 f, 3 f
1 3
1 8
Z A
H S
1 4
1 7
1 b ,3 b
1 b ,3 b
1 4
1 7
H S
M S
1 5
1 6
1 a , 3 a
1 a , 3 a
1 5
1 6
M S
H T 1 6 5 6 2
3 0 S S O P -A
H T 1 6 5 6 2 B
3 0 S S O P -B
Note: ²*² col indicates a blink colon and col¢ indicates a continuous light colon.
Pin Description
Pin Name
I/O
Description
VCC
¾
High voltage power supply pin.
VDD
O
Built-in regulator voltage output pin for the device internal circuits.
VSS
¾
Ground pin.
DIM1
I
DIM2
I
A/C
I
When the A/C pin is low, the internal circuits are reset.
The reset pulse width should be more than 2ms.
Internally connected to a pull-high resistor.
ZA
I
Zero Adjustment pin.
Internally connected to a pull-high resistor.
HS
I
Hour Adjustment pin.
Internally connected to a pull-high resistor.
MS
I
Minute Adjustment pin.
Internally connected to a pull-high resistor.
BLANK
I
When low the Blank input pin will extinguish the display.
Internally connected to a pull-down resistor.
XT
O
XT
I
TEST
I
IC test pin - should be left open or kept at a low level
64Hz
O
64Hz signal output pin for oscillation frequency adjustment
GR1
O
GR2
O
1a,3a ~
2b,4b,4c
O
Illumination level control pins.
Internally connected to pull-down resistors.
Crystal oscillator pin
Grid output pins for 1/2 duty VFD
Rev. 1.30
Segment output pins for 1/2 duty VFD
2
May 24, 2012
HT16562
Approximate Internal Connections
A /C , Z A , H S , M S
D IM 1 , D IM 2 , T E S T , B L A N K
V
V
C C
V
6 4 H z
V
C C
D D
D D
V
D D
V S S
V S S
V S S
1 a , 3 a ~ 1 g , 3 g ; 2 a , 2 d ~ 2 g ;
G R 1 , G R 2
X T , X T
V
X T
( O s c illa to r O u tp u t)
C C
X T
( O s c illa to r In p u t)
V S S
V S S
Absolute Maximum Ratings
Logic Supply Voltage .................VSS-0.3V to VSS+6.5V
Driver Supply Voltage .................VSS-0.3V to VSS+20V
High Input Voltage .....................VSS-0.3V to VCC+0.3V
High Output Voltage ..................VSS-0.3V to VCC+0.3V
Logic Input Voltage ....................VSS-0.3V to VDD+0.3V
Logic Output Voltage .................VSS-0.3V to VDD+0.3V
Driver Output Voltage..........................VSS-0.3V to VCC
Driver Output Current (Segment Driver) -10mA to +2mA
Driver Output Current (Grid Driver) ......-7mA to +20mA
Storage Temperature ..........................-55°C to +150°C
Operating Temperature.........................-40°C to +85°C
Note: These are stress ratings only. Stresses exceeding the range specified under ²Absolute Maximum Ratings² may
cause substantial damage to the device. Functional operation of this device at other conditions beyond those listed
in the specification is not implied and prolonged exposure to extreme conditions may affect device reliability.
Recommended Operating Conditions
Symbol
Parameter
Min.
Typ.
Max.
Unit
VCC
Power Supply Voltage
4
¾
18
V
fOSC
Oscillation Frequency
¾
4.194304
¾
MHz
tOP
Operating Temperature
-40
¾
85
°C
Rev. 1.30
3
May 24, 2012
HT16562
D.C. Characteristics
VCC=12V, VSS=0V, Ta=-40°C~85°C
Test Conditions
Symbol
Parameter
VDD
Min.
Typ.
Max.
Unit
Conditions
VIH
High Input Voltage
¾
VCC= 8V to 18V
3.6
¾
¾
V
VIL
Low Input Voltage
¾
VCC= 8V to 18V
¾
¾
1
V
IIL1
Low-level Input Current
18V
Dim1, Dim2, BLANK,
Test pins low
-1
¾
¾
mA
IIH1
Hi-level Input Current
18V
Dim1, Dim2, BLANK,
Test pins high
50
¾
200
mA
IIL2
Low-level Input Current
18V XT pin low
-3
¾
3
mA
IIH2
Hi-level Input Current
18V XT pin high
-3
¾
3
mA
IIL3
Low-level Input Current
18V A/C, ZA, HS, MS pins low
-200
¾
-50
mA
IOL
Low-level Output current
12V VOL= 0.5V for 64Hz pin
100
¾
¾
mA
IOH
Hi-level Output current
12V VOL= 4.0V for 64Hz pin
¾
¾
-100
mA
ISOL
Driver Output Low Voltage
(All Segment outputs)
12V VSOL= 0.7V
15
¾
¾
mA
ISOH
Driver Output High Voltage
(All Segment outputs)
12V VSOL= 11.3V
¾
¾
-1.0
mA
IGOL
Driver Output Low Voltage
(Grid1,Grid2)
12V VSOL= 0.7V
15
¾
¾
mA
IGOH
Driver Output High Voltage
(Grid1,Grid2)
12V VSOL= 11.3V
¾
¾
-15
mA
ICC
Dynamic Current Consumption
fOSC= 4.194304MHz,
12V Oscillator external
capacitors = 22pF
¾
¾
0.8
mA
Rev. 1.30
4
May 24, 2012
HT16562
Functional Description
The TEST pin is used during manufacturing for device
testing purposes and should not be connected to any
external circuitry.
VFD Display Driving
The display can directly drive VFD signals dynamically
and does so at a 1/2 duty cycle rate. The clock will be
displayed in a 12-hour format with the hours ranging
from 1 to 12 and minutes from 00 to 59. If the most significant numeral is zero then the display will be extinguished.
Two illumination level set pins, DIM1 and DIM2, are provided to give control over the display brightness level, as
shown in the following table.
Switch Pin
Name
· Grid and segment connections
A single 7-segment display is shown below showing
the illumination pattern for each numeral.
A
F
E
B
G
D
C
7 -S e g m e n ts
Operating mode
Dim1
Dim2
L
L
f=256Hz, 1/2 duty (50% display)
H
L
f=256Hz, 1/4 duty (25% display)
L
H
f=256Hz, 1/8 duty (12.5% display)
H
H
f=256Hz, 1/16 duty (6.25% display)
Device Functions
· Reset
As the device is designed for clock applications, four
7-segment displays are required to display the correct
time output. The connections for the grids and segments are shown below, however it should be noted
that the fourth segment only requires two of its segments to be driven. Additionally it should be noted that
the colon can also be illuminated.
Although the device is provided with an external reset
pin A/C, the device will in fact reset itself when power
is applied, eliminating the need for external reset components. The usual provision of an external capacitor
is not required as an internal reset capacitor is integrated within the device.
· Internal regulator
G R 1
G R 2
3 a
3 f
4 b
4 c
d ig it4
3 e
c o l
3 d
2 f
3 b
3 g
3 c
d ig it3
2 e
c o l
c o lo n
d ig it2
1 f
2 b
2 g
2 d
An internal regulator function is also integrated within
the device providing a stable voltage power supply
source for the internal circuits. This allows the device
to operate with a wide external power supply ranging
from 4V to 18V.
1 a
2 a
2 c
1 e
1 b
1 g
1 d
1 c
d ig it1
· Chatter removal
The device contains circuits which are connected to
input pins HS, MS and ZA to remove chatter of less
than 31.25ms.
Other Pin Functions
The external reset pin A/C is used to reset the internal
circuits of the device. When this pin is pulled low the device will be reset, when the pin is allowed to go high, via
its internal pull-high resistor, then the display will indicate a ²1:00² output.
· Oscillator
The basic time base frequency for this device is determined by an external 4.194304MHz crystal. When an
external crystal along with two small external capacitors are connected to the two oscillator XT pins, the internal oscillator circuit will ensure generation of the
correct time base signals. The oscillation frequency,
although determined by the external crystal frequency, will also be influenced by the external capacitors, the crystal inherent capacitance and the residual
capacitance of the external PCB tracks. To ensure accurate frequency generation, the crystal specification
should be carefully consulted and the external capacitors and crystal should be placed as close to the device as possible.
The BLANK pin, if pulled low will extinguish the display.
Note that during the time when the BLANK pin is low, the
HS, MS and ZA pins will be automatically disabled by
the device and have no function.
The 64Hz pin allows monitoring of the system frequency
to allow frequency adjustments to be executed. As the
name suggests, this output pin will continuously output
a frequency of 64Hz.
Rev. 1.30
5
May 24, 2012
HT16562
minute value is presently less than 30 the only the
second and minute values will be reset to zero and the
hour value remain unchanged. However if the minute
value is presently at a value of 30 or higher then when
the zero adjustment function is executed, a carry will
be implemented and the hour value will be incremented by one. The following table illustrates a few
examples of this operation.
Time Adjustment Operation
· Hour/minute adjustment
Both the minutes and hour displays can be adjusted
separately or both together in a fast forward format.
The hour set pin, HS, and the minutes set pin, MS, are
used to make these adjustments. Both of these pins
are connected to internal pull-high resistors. Each
time one of these lines is pulled low, the respective
hour or minute value will increment by one, also if the
line is continuously held low then the respective value
will increment automatically at a rate of 2Hz. Both values will increment together if both lines are pulled low
simultaneously. Note that no carry functions will be implemented when either the hour or minute value overflows.
Zero Adjust Examples
Present Time
· Zero adjustment
A zero adjust function is also included within the device and is controlled by the ZA pin. This pin is connected to an internal pull-high resistor. Pulling this line
low will reset both the internal minutes and seconds
value, however the way in which the display is reset
depends upon the present value of the display. If the
After Zero Adjust
Hr.
Min.
Sec.
Hr.
Min.
Sec.
1
30
00
2
00
00
2
00
00
2
00
00
2
29
59
2
00
00
2
30
00
3
00
00
2
59
59
3
00
00
3
29
59
3
00
00
Application Circuits
V
V
C C
S W 7
C C
V
S W 6
C C
V
E F
C C
V
C C
F +
V C C
S W 5
R 1
2 c , c o l'
2 c , c o l
J u m p e r
1
3
2
2 c , c o l
2 a , 2 d
T E S T
D IM 2
A /C
Z A
H S
S W 2
S W 1
2 f
2 e
2 e
3 d , 1 d
3 e , 1 e
3 e , 1 e
3 c , 1 c
3 c , 1 c
3 g , 1 g
3 g , 1 g
3 f, 1 f
3 f, 1 f
3 b , 1 b
3 b , 1 b
3 a , 1 a
3 a , 1 a
G R 1
G R 1
G R 2
G R 2
X T
C 2
Y 1
4 .1 9 4 3 0 4 M H z
M S
X T
V D D
6 4 H z
V S S
1 /2 D u ty
V F D P a n e l
2 g
2 g
S W 8
S W 3
4 b , 4 c , 2 b
2 f
3 d , 1 d
B L A N K
S W 4
2 a , 2 d
4 b , 4 c , 2 b
D IM 1
F -
C 1
J u m p e r
1
2
Note: Capacitor C1 and C2 can adjust the accuracy of frequency
Rev. 1.30
6
May 24, 2012
HT16562
Package Information
Note that the package information provided here is for consultation purposes only. As this information may be updated at regular intervals users are reminded to consult the Holtek website (http://www.holtek.com.tw/english/literature/package.pdf) for
the latest version of the package information.
30-pin SSOP (209mil) Outline Dimensions
3 0
1 6
A
B
1 5
1
C
C '
G
D
E
F
H
=
· MO-150
Symbol
Dimensions in inch
Min.
Nom.
Max.
A
0.291
¾
0.323
B
0.197
¾
0.220
C
0.009
¾
0.013
C¢
0.390
¾
0.413
D
¾
¾
0.079
E
¾
0.026
¾
F
0.002
¾
¾
G
0.022
¾
0.037
H
0.004
¾
0.008
a
0°
¾
8°
Symbol
A
Dimensions in mm
Min.
Nom.
Max.
7.40
¾
8.20
B
5.00
¾
5.60
C
0.22
¾
0.33
C¢
9.90
¾
10.50
D
¾
2.00
E
¾
0.65
¾
F
0.05
¾
¾
G
0.55
¾
0.95
H
0.09
¾
0.21
a
0°
¾
8°
7
April 21, 2009
HT16562
Holtek Semiconductor Inc. (Headquarters)
No.3, Creation Rd. II, Science Park, Hsinchu, Taiwan
Tel: 886-3-563-1999
Fax: 886-3-563-1189
http://www.holtek.com.tw
Holtek Semiconductor Inc. (Taipei Sales Office)
4F-2, No. 3-2, YuanQu St., Nankang Software Park, Taipei 115, Taiwan
Tel: 886-2-2655-7070
Fax: 886-2-2655-7373
Fax: 886-2-2655-7383 (International sales hotline)
Holtek Semiconductor Inc. (Shenzhen Sales Office)
5F, Unit A, Productivity Building, No.5 Gaoxin M 2nd Road, Nanshan District, Shenzhen, China 518057
Tel: 86-755-8616-9908, 86-755-8616-9308
Fax: 86-755-8616-9722
Holtek Semiconductor (USA), Inc. (North America Sales Office)
46729 Fremont Blvd., Fremont, CA 94538, USA
Tel: 1-510-252-9880
Fax: 1-510-252-9885
http://www.holtek.com
Copyright Ó 2012 by HOLTEK SEMICONDUCTOR INC.
The information appearing in this Data Sheet is believed to be accurate at the time of publication. However, Holtek assumes no responsibility arising from the use of the specifications described. The applications mentioned herein are used
solely for the purpose of illustration and Holtek makes no warranty or representation that such applications will be suitable
without further modification, nor recommends the use of its products for application that may present a risk to human life
due to malfunction or otherwise. Holtek¢s products are not authorized for use as critical components in life support devices
or systems. Holtek reserves the right to alter its products without prior notification. For the most up-to-date information,
please visit our web site at http://www.holtek.com.tw.
Rev. 1.30
8
May 24, 2012