TC14433/A

DS21394D-page 12

© 2008 Microchip Technology Inc.

FIGURE 5-2:

3-1/2 Digit LED Voltmeter with Low Component Count Using Common Cathode

Display.

FIGURE 5-3:

Alternate Oscillator Circuits.

Note

3: Peak digit current for an eight displayed is 7 times the segment current:

*To increase segment current capability, add two 75491 ICs between 14511B and resistor network.

The use of the 1413 as digit driver increases digit current capability over the 75492.

**V can range between -2.8V and -11V.

CLK1

CLK0

OR

TC14433

Input

300 k

Ω

Resitor Network

or Individual

Resistor*

R

+5V

Minus

Control

+5V

Common

Cathode

Led Display

75492

OR

1413*

Digit Drivers

(Minus)

Alternate Overrange Circuit

with Separated LED

+5V

OR

1/6

1/7

1413

75492

OR

B1

A

B

C

D

LT

LE

I4511B

+5V

1µF

20k

Ω

MCP1525

470 k

Ω 0.1 µF 0.1 µF

EOE

a

b

c

d

e

f

g

(B) LC Oscillator Circuit

10

L

C

11

C

For L = 5 mH and C = 0.01 µF @ 22.5 kHz

TC14433

TC14433

11

10

18 M

Ω

47 k

Ω

(A) Crystal Oscillator Circuit

f

1

2

π LC

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