CS8190 datasheet(6/8 Pages) CHERRY

Part #	CS8190

Description	Precision Air-Core Tach/Speedo Driver with Return to Zero

PDF	8 Pages

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Manufacturer	CHERRY [Cherry Semiconductor Corporation]

Direct Link	http://www.cherrycorp.com/

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T-PW

FREQIN

ICP+

SQOUT

VCC

VREG

VCP+

3. Determine C4

C4 is selected to satisfy both the maximum allowable rip-

ple voltage and response time of the meter movement.

C4 =

With C4 = 0.47µF, the F/V ripple voltage is 44mV.

The last component to be selected is the return to zero

capacitor C2. This is selected by increasing the input sig-

nal frequency to its maximum so the pointer is at its max-

imum deflection and removing the power from the cir-

cuit. C2 should be large enough to ensure that the pointer

always returns to the 0¡ position rather than 360¡ under

all operating conditions.

Figure 7 shows how the CS8190 and the CS8441 are used

to produce a Speedometer and Odometer circuit.

CT(VREG Ð 0.7V)

VRIPPLE(MAX)

Circuit Description and Application Notes: continued

CPÐ

F/VOUT

F to V

2.0V

0.25V

CP+

VC(t)

+Ð

VREG

SQOUT

QSQUARE

2.0V

FREQIN

Figure 5A: Partial Schematic of Input and Charge Pump

CS8190 Datasheet(PDF) 6 Page - Cherry Semiconductor Corporation