IL8190N IKSEMICON [IK Semicon Co., Ltd], IL8190N Datasheet - Page 9

• Manufacturer Part Number: IL8190N
• Description: Precision Air-Core Tach/Speedo Driver with Return to Zero
• Manufacturer: IKSEMICON [IK Semicon Co., Ltd]

Design Example
any inaccuracies due to IC tolerances or meter
movement pointer placement.
2. Select R3 and R4
voltage regulator. The maximum output current
from the voltage regulator is 10 mA. R3 must
ensure that the current does not exceed this limit.
cycle of the input signal. Time for one cycle at
maximum frequency is 2.85 ms. To ensure that
C
time constant is less than 10% of the minimum
input period.
µ s
allowable ripple voltage and response time of the
meter movement.
mV.
to zero capacitor C2. This is selected by
increasing the input signal frequency to its
maximum so the pointer is at its maximum
deflection, then removing the power from the
circuit. C2 should be large enough to ensure that
Maximum meter Deflection = 270 °
Maximum Input Frequency = 350 Hz
1. Select R
Θ = 970 × FREQ × C
Let C
R
Resistor R3 sets the output current from the
Choose R3 = 3.3 k Ω
The charge current for C
C
CP
Choose R4 = 1.0 k Ω .
Discharge time:
t
Charge time:
t
3. Determine C4
C4 is selected to satisfy both the maximum
With C4 = 0.47 µ F, the V/F ripple voltage is 44
The last component to be selected is the return
DCHG
CHG
T
CP
is charged, assume that the (R3 + R4) C
should be a 250 k Ω potentiometer to trim out
must charge and discharge fully during each
= (R3 + R4)C
= R3 × C
CP
= 0.0033 µ F, find R
R
T
T
T
C
and C
=
V
=
4
CP
970
REG
10%
=
3.3
= 3.3 k Ω × 0.0033 µ F = 10.9 µ s
R
CP
C
×
-
T
CP
k
CP
×
0.7
350
= 243 k Ω
Ω
= 4.3 k Ω × 0.0033 µ F = 14.2
CP
(V
350
∆V
V
× R
Hz
REG
270
1
CP
Hz
=
MAX
×
T
T
°
is
. 1
−
0.0033
= 270°
=
90
0.7V)
285
mA
µs
µF
CP
the pointer always returns to the 0 ° position rather
than 360 ° under all operating conditions.
CS8441 are used to produce a Speedometer and
Odometer circuit.
IL8190N only as a driver for an air–core meter
having performed the V/F conversion elsewhere in
the circuit.
DC voltage ranging from 2.0 V to 6.0 V. This is
accomplished by forcing a voltage on the V
lead. The alternative scheme shown in Figure 10
uses an external op amp as a buffer and operates
over an input voltage range of 0 V to 4.0 V.
compensated.
0 V to 4.0 V DC
Figure 9. Driving the IL8190N from an External
External DC Voltage Using an Op Amp Buffer
Figure 11 shows how the IL8190N and the
In some cases a designer may wish to use the
Figure 9 shows how to drive the IL8190N with a
Figures 9 and 10 are not temperature
V
IN
2.0 V to 6.0 V DC
Figure 10. Driving the IL8190N from an
V
100 kΩ
100 kΩ
IN
10 kΩ
100 kΩ
+
DC Voltage
N/C
100 kΩ
100 kΩ
10 kΩ
V
CP-
V
REG
OUT
BIAS
/F
+
IL8190N
BIAS
V
CP-
OUT
/F
+
IL8190N
IL8190N
OUT
/F
9