7106

CMOS IC

UNISONICTECHNOLOGIESCO.,LTD

11 of 18

www.unisonic.com.tw

QW-R502-018.E

DETAILED DESCRIPTION(Cont.)

DIGITAL SECTION

Fig.5 show the digital section for the UTC 7106, respectively. In the UTC 7106, an internal digital ground is

generated from a 6V Zener diode and a large P-Channel source follower. This supply is made stiff to absorb the

relative large capacitive currents when the back plane(BP) voltage is switched. The BP frequency is the clock

frequency divided by 800. For three readings/sec, this is a 60Hz square wave with a nominal amplitude of 5V. The

segments are driven at the same frequency and amplitude and are in phase with BP when OFF, but out of phase

when ON. In all cases negligible DC voltage exists across the segments.

LCD PHASE DRIVER

7

SEGMENT

DECODE

7

SEGMENT

DECODE

7

SEGMENT

DECODE

LATCH

1000 s

COUNTER

,

100 s

COUNTER

,

10 s

COUNTER

,

1 s

COUNTER

,

BACKPLANE

LOGIC

CONTROL

FROM COMPARATOR OUTPUT

CLOCK

40

39

38

OSC 1

OSC 2

OSC 3

Fig.5 Digital Section

26

37

6.2V

500Ω

TEST

V-

V+

1

21

TYPICAL SEGMENT OUTPUT

SEGMENT

OUTPUT

2mA

0.5mA

V+

INTERNAL DIGITAL GROUND

INTERNAL

DIGITAL

GROUND

*

a

b

a

b

g

f

e

c

d

a

b

g

f

e

c

d

a

b

g

f

e

c

d

TO SWITCH DRIVERS