Functional Description; Voltage Multiplier - Epson SCI 7654 Series Technical Manual

FUNCTIONAL DESCRIPTION

Oscillator
The on-chip RC oscillator network frequency is deter-
mined by the external resistor, R
tween OSC1 and OSC2. This oscillator can be disabled
in favor of an external clock by leaving OSC2 open and
applying an external clock signal to OSC1.
Oscillator
OSC1 OSC1
R
OSC
OSC2 OSC2
Reference Volatge Generator and Voltage
Regulator
The reference voltage generator supplies a reference
voltage to the voltage regulator to control the output.
This voltage can be switched ON and OFF.
V
DD
POFF
RV
V
REG
SCI7000 Series
Technical Manual
, connected be-
OSC
External clock
External clock
signal
Control signal
R = 100 k to 1 M
RV
EPSON

Voltage Multiplier

The voltage multiplier uses the clock signal from the
oscillator to double or triple the input voltage. This re-
quires three external capacitors–two charge-pump ca-
pacitors between CAP1+ and CAP1– and CAP2+ and
CAP2–, respectively, and a smoothing capacitor be-
tween V and V .
I O
V = 0 V
DD
1
C1 +
10 F
2
3
5 V
C2 +
10 F
4
5
6
7
V = –5 V
I
+
C3
10 F
Double voltage potential levels
V
CC
(+5V)
V = 0 V
DD
GND
V = –5 V
I
(–5V)
V – = 2V
CAP2
Tripled voltage potential levels
V = 0 V
DD
V = –5 V
I
V = 3V = –15 V
O I
SCI7661 Series
14
R
13 R1 RV
R 100 k
OSC
1 M to
R2
12
1 M
11
+ C4
10 F
10
9
V = –8 V
REG
V = –15 V
8
O
= –10 V
I
2–11