GSI-3000J Series
External Variable Output Voltage Circuit
1. Variable output voltage with a single external resistor
VIN
GND
5
+
OPEN
2
47µF
SI-3000J
1
3
IREX
4
VO
REX
V04
+
47µF
GND
The output voltage may be increased by inserting resistor REX between
terminals No.4 (sensing terminal) and No.3 (output terminal). The cur-
rent IREX flowing into terminal No.4 is 1mA (typ.), therefore the adjusted
output voltage VOUT is:
VO=V04+IREX•REX *V04: output voltage of SI-3000J series
However, the internal resistor (between terminals No. 4 and No.1) is a
semiconductor resistor, which has approximately thermal characteris-
tics of +0.2%/°C.
It is important to keep the thermal characteristics in mind when adjust-
ing the output voltage.
2. Variable output voltage with two external resistors
VIN
VO
5
3
GND
+
OPEN
2
47µF
SI-3000J
1
IREX1
4
I4IN
REX1
V04
REX2
+
47µF
GND
The output voltage may be increased by inserting resistors REX1 be-
tween terminals No.4 (sensing terminal) and No.3 (output terminal) and
REX2 between terminals No.4 and No.1 (ground terminal).
The current I4IN flowing into terminal No.4 is 1mA (typ.) so the thermal
characteristics may be improved compared to the method shown in 1
by setting the external current IREX1 at approximately 5 times the value
of I4IN (stability coefficient S=5).
The adjusted output voltage VOUT in this case is:
VO=V04+REX1•IREX1
IREX1=S•I4IN
The value of the external resistors may be obtained as follows:
VO-V04
V04
REX1=
REX2=
S•I4IN ,
(S-1)•I4IN
*V04: Output voltage of SI=3000J series
S: Stability coefficient of I4IN (may be set to any value)
Note: In the SI-3000J series, the output voltage increase can be ad-
justed as mentioned above. However, when the rise is set to ap-
proximately 10V compared to output voltage V04, the necessary
output current may not be obtained due to the S.O.A. protection
circuit in the SI-3000J series.
25
VIN=VO+1V
20
15
10
SI-3150J
SI-3120J
SI-3090J
SI-3050J
50
2
4
6
8
10
External Resistor REX (kΩ)
25
VIN=VO+1V
20
15
10
SRIE-X321=35.075JkΩ
SRI-E3X122=03JkΩ
SIR-3E0X29=02J.25kΩ
SIR-3E0X52=01J.25kΩ
5
0
1.0
2.0
External Resistor REX1 (kΩ)
46