7

Speedometer/Odometer or Tachometer Application

In some cases a designer may wish to use the CS8190 only

as a driver for an air-core meter having performed the F/V

conversion elsewhere in the circuit.

Figure 8 shows how to drive the CS8190 with a DC voltage

ranging from 2V to 6V. This is accomplished by forcing a

in Figure 9 uses an external op amp as a buffer and oper-

ates over an input voltage range of 0V to 4V.

Figure 8. Driving the CS8190 from an external DC voltage.

An alternative solution is to use the CS4101 which has a

separate function generator input lead and can be driven

directly from a DC source.

Figure 9. Driving the CS8190 from an external DC voltage using an Op

Amp Buffer.

0V to 4V DC

CP-

CS8190

BIAS

100k

W

100k

W

+

-

+

-

10k

W

100k

W

100k

W

CP-

CS8190

BIAS

10k

W

100k

W

N/C

2V to 6V DC

Figure 6

R1 - 3.9, 500mW

R2 - 10k½

R3 - 3k½

R4 - 1k½

C1 - 0.1µF

C2 -

1. Stand alone Speedo or Tach with return to Zero, 2000µF

2. With CS8441 application, 10µF

C3 - 0.1µF

C4 - 0.47µF

D1 - 1A, 600 PIV

D2 - 50V, 500mW Zener

Note 1: C2 (> 2000µF) is needed if return to zero function is required.

Note 2: The product of C4 and R4 have a direct effect on gain and

therefore directly effect temperature compensation.

Note 3: C4 Range; 20pF to .2µF.

Figure 7

Note 4: R4 Range; 100k½ to 500k½.

Note 5: The IC must be protected from transients above 60V and reverse

battery conditions.

2

3

4

5

6

7

8

Gnd

Gnd

COS+

COS-

16

15

14

13

12

11

10

9

CP-

Gnd

Gnd

SINE+

SINE-

BIAS

R3

C3

C1

D2

R1

D1

+

C4

COSINE

SINE

Air Core

Gauge

200

W

Speedometer

Gnd

Battery

Speedo

Input

R2

R4

1

CS8441

C2

Air Core

Stepper Motor

200

W

Odometer

CP+

2

3

4

5

6

7

8

Gnd

Gnd

COS+

COS-

16

15

14

13

12

11

10

9

CP-

Gnd

Gnd

SINE+

SINE-

BIAS

R3

C3

C1

D2

R1

D1

+

C4

COSINE

SINE

Air Core

Gauge

200

W

Speedometer

Gnd

Battery

Speedo

Input

C2

R2

R4

CP+