Kikusui PLZ-4W Series, User Manual

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A-6 Appendix PLZ-4W
A.2.3 Operation of the CP Mode
In CP mode, the PLZ-4W sinks current so that the power consumed inside the elec-
tonic load is constant.
■
CP mode operation
When the PLZ-4W is used in CP mode, the PLZ-4W operates as a constant power
load as shown in Fig. A-7. When the voltage (V1) of the constant-voltage power
supply increases the input current (I) decreases so that the power consumed by the
PLZ-4W P = V
× I is kept constant. In Fig. A-7, P = V2 × I2 = V3 × I3.
Fig. A-7 Equivalent circuit of the CP mode and operation
■
Transition of the operating point: Overcurrent protection
(OCP)
We will consider the case when checking the load characteristics of the constant-
voltage power supply of Fig. A-7 using CP mode.
Fig. A-8 Transition of the operating point in CP mode (OCP trip point)
0
V
2
V
1
I
1
I
2
V
2
V
1
I
1
I
2
= =
P
Rated maximum
current value
I
V
Current I
Voltage V
Power (current
×
voltage) is constant
even when the current and voltage vary
PLZ-4W Series Electronic Load
Constant voltage
power supply
V
1
Input current [A]
Input
voltage [V]
Log scale
Constant power line
(Constant power settings: P
1
, P
2
, and P
B
)
Constant current line
(OCP setting)
Operating area
OCP trip point
B
V
1
V
3
G
A
H
A
1
A
2
P
1
P
2
P
B