R
H1137
Block Diagram
P u ls e W id th
D iv id e r
O s c illa to r
In itia l D iv id e r
D iv id e r 1 H z
O S C
IN
O S C
OUT
M o to r L o g ic
P u ls e R e p e titio n
D iv id e r
T e s t L o g ic
M o to r D r iv e r
M a s te r R e s e t
TEST
MOT
1
MOT
2
RESET
Fig. 4
Pin Assignments
Name
V
N
V
P
OSC
IN
OSC
OUT
MOT
1
MOT
2
RESET
TEST
Function
Negative supply voltage
Positive supply voltage
Oscillator input
Oscillator output
Motor drive output 1
Motor drive output 2
Reset input
Test input / output
Test mode
The TEST pad fulfils two functions:
a) For normal operation, the TEST pad is left open. The
circuit outputs a square wave signal of 512Hz which
can be used for tuning the oscillator.
b) If the TEST pad is connected to V
P
, the period for
the motor pulses changes to either 2 x 31.25 ms or
2 x 62.5 ms (mask options), while the motor pulse
width remains unchanged (fast motor test).
Test
Functional Description
Oscillator
The 32’768Hz clock frequency is generated by a crystal
oscillator. Input and output capacitors are integrated in
the chip. Their values are metal mask selectable.
Motor drive output
The H1137 contains two push-pull output buffers for driv-
ing bipolar stepping motors (see Fig. 3). Between two
pulses, the two p-channel devices are active for motor
damping.
Reset
Pulling the RESET input to V
P
resets the frequency di-
viders and disables the motor pulses. Motor pulses in
progress when the RESET function is applied, will be
completed. After releasing the RESET pad from V
P
, the
next motor pulse appears with a delay of one half motor
cycle on the drive output MOT
1
if the last motor pulse
appeared on MOT
2
or vice-versa (see Fig. 3). Due to the
debounce circuitry on the RESET input, V
P
must be ap-
plied for at least 23.4 ms to be accepted as RESET.
Test Pad
Connected to
V
P
Open
Function
Fast motor
test
Normal
operation
Description
Increase the frequency for the
motor pulses to 16Hz (32Hz)
Output of square wave signal
(512Hz)
Test configuration
V
P
RL
Reset
RESET
MOT
1
MOT
2
V
P
OSC
OUT
V
P
H1137
Test
TEST
V
N
C
TR
V
N
V
P
Operating range of Trimmer Capacitance:
3pF
≤
C
TR
≤
30 pF
OSC
IN
Fig. 5
Copyright
©
2004, EM Microelectronic-Marin SA
4
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EMMICRO [ EM MICROELECTRONIC - MARIN SA ]
