Epson – Epson Power Supply S1F70000 User Manual
Page 69
S1F76540 Series
2–26
EPSON
S1F70000 Series
Technical Manual
Setup:
• Relationship between V
REG
and reference voltage
V
REG
=
R1 + R2
×
(Reference voltage)
• • • • Equation (1)
R1
• Current consumption of division resistors
I
REG
=
| V
REG
|
• • • • Equation (2)
R1 + R2
Setup example:
• To output V
REG
= –18 V by four-time boosting if V
I
= –5 V and V
O
= –20 V
First, determine the total resistance of division resistors R1 and R2. If the current consumption is assumed to be 20
µ
A, the total resistance can be obtained from equation (2) as follows:
R1 + R2 = 12V
÷
20
µ
A = 900 k
Ω
If the reference voltage is -1.5 V, the division resistance ratio can be obtained from equation (1) as follows:
(R1 + R2) / R2 = (–18 V)
÷
(–1.5 V) = 12
Therefore, R1 and R2 are:
R1 = 75 k
Ω
R2 = 825 k
Ω
Figure 2.5 V
REG
setup and mounting notes
R1
V
O
V
RI
V
REG
RV
V
DD
FC
TC1
TC2
C2P
C2N
C3N
C1N
C1P
V
I
P
OFF1
P
OFF2
R2
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9