ETC CS4101/D

CS4101
CS4101
DE
SI
GN
Precision Air-Core Tach/Speedo Driver
with Separate Function Generator Input
Description
EW
tachometer drivers such as the
CS289 or LM1819. The output utilizes differential drivers which eliminates the need for a zener reference
and offers more torque. The device
withstands 60V transients which
decreases the protection circuitry
required. The device is also more
precise than existing devices allowing for fewer trims and for use in a
speedometer.
AR
CH
IF V
OR E
N
The CS4101 is specifically designed
for use with air-core meter movements. The IC provides all the functions necessary for an analog
tachometer or speedometer. The
CS4101 takes a speed sensor input
and generates sine and cosine related output signals to differentially
drive an air-core meter.
Many enhancements have been
added over industry standard
Features
■ Direct Sensor Input
■ High Output Torque
■ Low Pointer Flutter
■ High Input Impedance
■ Overvoltage Protection
Absolute Maximum Ratings
RE
CO
MM
EN
DE
D
Supply Voltage (<100ms pulse transient) .........................................VCC = 60V
(continuous)..............................................................VCC = 24V
Operating Temperature .............................................................–40°C to +105°C
Storage Temperature..................................................................–40°C to +165°C
Junction Temperature .................................................................–40°C to+150°C
ESD (Human Body Model) .............................................................................4kV
Lead Temperature Soldering
Wave Solder(through hole styles only).............10 sec. max, 260°C peak
Block Diagram
SQOUT
Charge Pump
–
CP+
+
BIAS
NO
T
FREQIN
FGEN
Voltage
Regulator
–
VREG
Gnd
Gnd
VREG
7.0V
Gnd
DE
VI
CE
Gnd
COS+
–
–
+
COS
Output
+
Func.
Gen.
SINE+
SINE
Output
+
+
–
–
SINE-
COS-
VCC
F/VOUT
20 Lead PDIP
CP-
Input
Comp.
+
Package Option
CP+ 1
20
CP-
SQOUT
2
19
F/VOUT
FREQIN
3
18
VREG
BIAS
4
17
NC
Gnd 5
16
Gnd
Gnd 6
15
Gnd
NC
7
14
NC
COS+ 8
13
SIN+
COS- 9
12
SIN-
VCC 10
11
FGEN
High Voltage
Protection
ON Semiconductor
2000 South County Trail, East Greenwich, RI 02818
Tel: (401)885–3600 Fax: (401)885–5786
N. American Technical Support: 800-282-9855
Web Site: www.onsemi.com
April, 2001 - Rev. 5
1
CS4101
Electrical Characteristics: -40°C ≤ TA ≤ 85°C, 8.5V ≤ VCC ≤ 15V unless otherwise specified.
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
8.5
50
125
mA
13.1
16.0
V
4.4
■ Supply Voltage Section
ICC Supply Current
VCC = 16V, -40°C, No Load
VCC Normal Operation Range
■ Input Comparator Section
Positive Input Threshold
2.4
3.4
Input Hysteresis
200
400
Input Bias Current *
0V ≤ VIN ≤ 8V
-10
Input Frequency Range
0
Input Voltage Range
in series with 1kΩ
Output VSAT
ICC = 10mA
Output Leakage
VCC = 7V
-1
0.15
Low VCC Disable Threshold
7.0
Logic 0 Input Voltage
2.4
8.0
V
mV
-80
µA
20
KHz
VCC
V
0.40
V
10
µA
8.5
V
V
*Note: Input is clamped by an internal 12V Zener.
■ Voltage Regulator Section
Output Voltage
6.25
7.00
Output Load Current
7.50
V
10
mA
Output Load Regulation
0 to 10 mA
10
50
mV
Output Line Regulation
8.5V ≤ VCC ≤ 16V
20
150
mV
Power Supply Rejection
VCC = 13.1V, 1Vp/p 1kHz
34
46
dB
1.5
2.0
2.5
V
40
150
nA
2.0
2.5
V
0.7
1.1
V
-0.10
0.28
+0.70
%
7
10
13
mV/Hz
■ Charge Pump Section
Inverting Input Voltage
Input Bias Current
Vbias Input Voltage
1.5
Non Invert. Input Voltage
IIN = 1mA
Linearity*
@ 0, 87.5, 175, 262.5, + 350Hz
F/VOUT Gain
@ 350Hz, CT = 0.0033µF, RT = 243kΩ
Norton Gain, Positive
IIN = 15µA
0.9
1.0
1.1
I/I
Norton Gain, Negative
IIN = 15µA
0.9
1.0
1.1
I/I
*Note: Applies to % of full scale (270°).
■ Function Generator Section: -40° ≤ TA ≤ 85°C, VCC = 13.1V unless otherwise noted.
Differential Drive Voltage
(VCOS+ - VCOS-)
Differential Drive Voltage
(VSIN+ - VSIN-)
Differential Drive Voltage
(VCOS+ - VCOS-)
Differential Drive Voltage
(VSIN+ - VSIN-)
Differential Drive Current
8.5V ≤ VCC ≤ 16V
Θ = 0°
8.5V ≤ VCC ≤ 16V
Θ = 90°
8.5V ≤ VCC ≤ 16V
Θ = 180°
8.5V ≤ VCC ≤ 16V
Θ = 270°
8.5V ≤ VCC ≤ 16V
Zero Hertz Output Angle
Function Generator Error *
Reference Figures 1,2,3,4
VCC = 13.1V
Θ = 0° to 305°
* Note: Deviation from nominal per Table 1 after calibration at 0 and 270°.
2
5.5
6.5
7.5
V
5.5
6.5
7.5
V
-7.5
-6.5
-5.5
V
-7.5
-6.5
-5.5
V
33
42
mA
-1.5
0.0
1.5
deg
-2
0
+2
deg
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
■ Function Generator Section: continued
Function Generator Error
13.1V ≤ VCC ≤ 16V
-2.5
0
+2.5
deg
Function Generator Error
13.1V ≤ VCC ≤ 11V
-1
0
+1
deg
Function Generator Error
13.1V ≤ VCC ≤ 9V
-3
0
+3
deg
Function Generator Error
25°C ≤ TA ≤ 80°C
-3
0
+3
deg
Function Generator Error
25°C ≤ TA ≤ 105°C
-5.5
0
+5.5
deg
Function Generator Error
–40°C ≤ TA ≤ 25°C
-3
0
+3
deg
Function Generator Gain
TA = 25°C Θ vs F/VOUT
60
77
95
°/V
Package Lead Description
PACKAGE LEAD #
LEAD SYMBOL
FUNCTION
20L
1
CP+
Positive input to charge pump.
2
SQOUT
Buffered square wave output signal.
3
FREQIN
Speed or rpm input signal.
4
BIAS
Test point or Zero adjustment.
5, 6, 15, 16
Gnd
Ground Connections.
7, 14, 17
NC
No Connection.
8
COS+
Positive cosine output signal.
9
COS-
Negative cosine output signal.
10
VCC
Ignition or battery supply voltage.
11
FGEN
Function generator input signal.
12
SIN-
Negative sine output signal.
13
SIN+
Positive sine output signal.
18
VREG
Voltage regulator output.
19
F/VOUT
Output voltage proportional to input signal frequency.
20
CP-
Negative input to charge pump.
Typical Performance Characteristics
Figure 2: Charge Pump Output Voltage vs Output Angle
Figure 1: Function Generator Output Voltage
vs Degrees of Deflection
F/VOUT = 2.0V + 2 FREQ × CT × RT × (VREG - 0.7)
7
7
6
5
3
2
5
F/V Output (V)
Output Voltage (V)
6
COS
4
1
0
-1
-2
-3
4
3
2
-4
-5
1
SIN
-6
-7
0
45
90
135
180
225
270
0
315
0
Degrees of Deflection (°)
45
90
135
180
225
Frequency/Output Angle (°)
3
270
315
CS4101
Electrical Characteristics: -40°C ≤ TA ≤ 85°C, 8.5V ≤ VCC ≤ 15V unless otherwise specified.
CS4101
Typical Performance Characteristics continued
Figure 4: Nominal Output Deviation
Figure 3: Output Angle in Polar Form
1.50
7V
1.25
(VSINE+) - (VSINE-)
1.00
Θ
Deviation (°)
0.75
Angle
+7V
–7V
0.50
0.25
0.00
-0.25
-0.50
-0.75
(VCOS+) - (VCOS-)
-1.00
-1.25
-1.50
Θ = ARCTAN
[
VSIN+ – VSINVCOS+ – VCOS-
]
0
45
90
135
180
Theoretical Angle (°)
-7V
225
270
315
Nominal Angle vs. Ideal Angle (After calibrating at 180°)
Note: Temperature, voltage and nonlinearity not included.
45
40
35
Ideal Angle (Degrees)
30
25
20
Ideal Degrees
15
Nominal Degrees
10
5
0
1
5
9
13
17
21
25
29
33
37
41
45
Nominal Angle (Degrees)
Table 1: Function Generator Output Nominal Angle vs. Ideal Angle (After calibrating at 270°)
Ideal Θ
Degrees
Nominal
Θ Degrees
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
0
1.09
2.19
3.29
4.38
5.47
6.56
7.64
8.72
9.78
10.84
11.90
12.94
13.97
14.99
16.00
17.00
Ideal Θ Nominal
Degrees Θ Degrees
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
17.98
18.96
19.92
20.86
21.79
22.71
23.61
24.50
25.37
26.23
27.07
27.79
28.73
29.56
30.39
31.24
32.12
Ideal Θ Nominal
Degrees Θ Degrees
34
35
36
37
38
39
40
41
42
43
44
45
50
55
60
65
70
33.04
34.00
35.00
36.04
37.11
38.21
39.32
40.45
41.59
42.73
43.88
45.00
50.68
56.00
60.44
64.63
69.14
Note: Temperature, voltage and nonlinearity not included.
4
Ideal Θ
Degrees
Nominal
Θ Degrees
75
80
85
90
95
100
105
110
115
120
125
130
135
140
145
150
155
74.00
79.16
84.53
90.00
95.47
100.84
106.00
110.86
115.37
119.56
124.00
129.32
135.00
140.68
146.00
150.44
154.63
Ideal Θ Nominal
Degrees Θ Degrees
160
165
170
175
180
185
190
195
200
205
210
215
220
225
230
235
240
159.14
164.00
169.16
174.33
180.00
185.47
190.84
196.00
200.86
205.37
209.56
214.00
219.32
225.00
230.58
236.00
240.44
Ideal Θ Nominal
Degrees Θ Degrees
245
250
255
260
265
270
275
280
285
290
295
300
305
244.63
249.14
254.00
259.16
264.53
270.00
275.47
280.84
286.00
290.86
295.37
299.21
303.02
The response time of the F/V is determined by the time
constant formed by RT and C4. Increasing the value of C4
will reduce the ripple on the F/V output but will also
increase the response time. An increase in response time
causes a very slow meter movement and may be unacceptable for many applications.
The CS4101 is specifically designed for use with air-core
meter movements. It includes an input comparator for
sensing an input signal from an ignition pulse or speed
sensor, a charge pump for frequency to voltage conversion, a bandgap voltage regulator for stable operation,
and a function generator with sine and cosine amplifiers
to differentially drive the motor coils.
From the simplified block diagram of Figure 5A, the
input signal is applied to the FREQIN lead, this is the
input to a high impedance comparator with a typical positive input threshold of 3.4V and typical hysteresis of
0.4V. The output of the comparator, SQOUT, is applied to
the charge pump input CP+ through an external capacitor CT. When the input signal changes state, CT is
charged or discharged through R3 and R4. The charge
accumulated on CT is mirrored to C4 by the Norton
Amplifier circuit comprising Q1, Q2 and Q3. The charge
pump output voltage, F/VOUT, ranges from 2V to 6.3V
depending on the input signal frequency and the gain of
the charge pump according to the formula:
Design Example
Maximum meter Deflection = 270°
Maximum Input Frequency = 350Hz
1. Select RT and CT
Θ = AGEN × ∆F/V
∆F/V = 2 × FREQ × CT × RT × (VREG – 0.7V)
Θ = 970 × FREQ × CT × RT
Let CT = 0.0033µF, Find RT
270°
RT = 970 × 350Hz × 0.0033µF
F/VOUT = 2.0V + 2 × FREQ × CT × RT × (VREG – 0.7V)
RT is a potentiometer used to adjust the gain of the F/V
output stage and give the correct meter deflection. The
F/V output voltage is applied to the function generator
input lead, FGEN. An additional filter circuit can be added
between F/VOUT and FGEN to reduce needle flutter. The
output voltage of the sine and cosine amplifiers are
derived from the on-chip amplifier and function generator circuitry. The various trip points for the circuit (i.e., 0°,
90°, 180°, 270°) are determined by an internal resistor
divider, and the bandgap voltage reference. The coils are
differentially driven, allowing bidirectional current flow
in the outputs, thus providing up to 305° range of meter
deflection. Driving the coils differentially offers faster
response time, higher current capability, higher output
voltage swings, and reduced external component count.
The key advantage is a higher torque output for the
pointer.
The output angle, Θ, is equal to the F/V gain multiplied
by the function generator gain:
Θ = AF/V × AFG,
where:
AFG = 77°/V (typ)
RT = 243kΩ
RT should be a 250kΩ potentiometer to trim out any inaccuracies due to IC tolerances or meter movement pointer
placement.
2. Select R3 and R4
Resistor R3 sets the output current from the voltage regulator. The maximum output current from the voltage regulator is 10mA R3 must ensure that the current does not
exceed this limit.
Choose R3 = 3.3kΩ
The charge current for CT is:
VREG – 0.7V
= 1.90mA
3.3kΩ
C1 must charge and discharge fully during each cycle of
the input signal. Time for one cycle at maximum frequency is 2.85ms. To ensure that CT is discharged, assume that
the (R3 + R4) CT time constant is less than 10% of the
minimum input frequency pulse width.
T = 285µs
The relationship between input frequency and output
angle is:
Choose R4 = 1kΩ.
Θ = AFG × 2 × FREQ × CT × RT × (VREG – 0.7V)
Charge time:
or,
Θ = 970 × FREQ × CT × RT
The ripple voltage at the F/V converter’s output is determined by the ratio of CT and C4 in the formula:
∆V =
T = R3 × CT = 3.3kΩ × 0.0033µF = 10.9µs
Discharge time:T = (R3 + R4)CT = 4.3kΩ × 0.0033µF = 14.2µs
3. Determine C4
C4 is selected to satisfy both the maximum allowable ripple voltage and response time of the meter movement.
CT(VREG – 0.7V)
C4
Ripple voltage on the F/V output causes pointer or needle flutter especially at low input frequencies.
C4 =
CT(VREG – 0.7V)
VRIPPLE(MAX)
With C4 = 0.47µF, the F/V ripple voltage is 44mV.
Figure 7 shows how the CS4101 and the CS-8441 are used
to produce a speedometer and odometer circuit.
5
CS4101
Circuit Description and Application Notes
CS4101
Circuit Description and Application Notes: continued
VREG
2.0V
R3
CT
SQOUT
0.25V
Q3
R4
Q2
3.4V
Figure 5A: Partial Schematic of Input and Charge Pump
T
PW
T-PW
VCC
FREQIN 0
VREG
0
ICP+
VCP+
0
Figure 5B: Timing Diagram of FREQIN and ICP
6
RT
C4
Q1
QSQUARE
–
CP–
CP+
+
SQOUT
F to V
–
VC(t)
+ –
FREQIN
F/VOUT
+
CS4101
Speedometer/Odometer or Tachometer Application
1
CP+
2
SQOUT
CT
R2
C3
Battery
CP- 20
+
RT
VREG 18
3
FREQIN
4
BIAS
5
Gnd
6
Gnd
7
NC
8
COS+
SIN+ 13
9
COS-
SINE- 12
10
C4
F/VOUT 19
NC 17
CS4101
R4
R3
Speedo
Input
Gnd 16
Gnd 15
NC 14
VCC
FGEN 11
D1 R1
D2
C1
C2
COSINE
SINE
Speedometer
Air Core
Gauge
200Ω
Figure 6
C4 - 0.47µF
CT - 0.0033µF, +/- 30 PPM/°C
D1 - 1A, 600 PIV
D2 - 50V, 500mW Zener
Note 1: For 58% Speed Input TMAX ≤ 5/fMAX where
R1 - 3.9, 500mW
R2 - 10kΩ
R3 - 3kΩ
R4 - 1kΩ
RT - Trim Resistor +/- 20 PPM/DEG. C
C1 - 0.1µF
C2 - 1. Stand alone Speedo or Tach "0" µF
2. Stand alone Speedo or Tach with return to Zero, 2000µF
3. With CS-8441 application, 10µF
C3 - 0.1µF
fMAX = maximum speed input frequency
R4
1
CP+
2
SQOUT
CT
Speedo
Input
R2
C3
Battery
CP- 20
F/VOUT 19
FREQIN
4
BIAS
5
Gnd
6
Gnd
7
NC
8
COS+
SIN+ 13
9
COS-
SINE- 12
VCC
10
C4
+
RT
VREG 18
3
NC 17
CS4101
R3
TMAX = CT(R3+R4)
Gnd 16
Gnd 15
NC 14
FGEN 11
D1 R1
D2
C1
COSINE
SINE
Air Core
Gauge
200Ω
C2
Speedometer
1
CS8441
Air Core
Stepper Motor
200Ω
Odometer
Figure 7
Note 4: The IC must be protected from transients above
60V and reverse battery conditions
Note 5: Additional filtering on the FREQIN lead may be
required
Note 1: The product of CT and RT have a direct effect on
gain and therefore directly effect temperature
compensation
Note 2: C4 Range; 20pF to .2µF
Note 3: R4 Range; 100kΩ to 500kΩ
7
CS4101
Package Specification
PACKAGE THERMAL DATA
PACKAGE DIMENSIONS IN mm (INCHES)
Thermal Data
RΘJC
typ
RΘJA
typ
D
Lead Count
20 Lead PDIP
Metric
Max Min
26.92 24.89
English
Max Min
1.060 .980
20L PDIP
25
65
°C/W
°C/W
Plastic DIP (N); 300 mil wide
7.11 (.280)
6.10 (.240)
8.26 (.325)
7.62 (.300)
1.77 (.070)
1.14 (.045)
2.54 (.100) BSC
3.68 (.145)
2.92 (.115)
.356 (.014)
.203 (.008)
0.39 (.015)
MIN.
.558 (.022)
.356 (.014)
REF: JEDEC MS-001
D
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Semiconductor reserves the right to make changes without
further notice to any products herein. For additional information and the latest available information, please contact
your local ON Semiconductor representative.
Ordering Information
Part Number
CS4101EN20
Some 8 and 16 lead
packages may have
1/2 lead at the end
of the package.
All specs are the same.
Description
20L PDIP
8
© Semiconductor Components Industries, LLC, 2001