Kikusui PAT160-25T, Operation Manual

Page: 49 / 218

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When operating in CC mode, the output current is maintained at the preset current.
Output voltage V is determined by the relationship defined by the equation V = Is
×
R
L
. It is a voltage less than voltage limit Vs. In this mode, the actual voltage that is
applied is not necessarily equal to the specified value.
For loads that generate transient surge voltage, preset voltage Vs must be set so that
the surge voltage does not reach the voltage limit.
■
Crossover point
CV mode and CC mode switch automatically according to the changes in the load.
The point at which the mode switches is called the crossover point.
For example, if the load changes and the output current reaches the current limit
when operating in CV mode, the operation mode automatically switches to CC to
protect the load. Likewise, if the output voltage reaches the voltage limit when
operating in CC mode, the operation mode automatically switches to CV.
CV and CC mode operation example
This section uses a power supply with a rated output voltage of 100 V and a rated
output current of 10 A as an example.
A load resistance (R
L
) of 8
Ω
is connected to the output terminals of the power
supply. The output voltage and output current are set to 30 V and 5 A, respectively.
In this case, Rc = 30 V/5 A = 6
Ω
. Since, 8
Ω
is greater than 6
Ω
(R
L
> Rc), the
operation mode is CV. If you want to increase the voltage in CV mode, the voltage
can be increased up to the voltage defined by the following equation: Vs = Is
×
R
L
.
Substituting the values, we obtain Vs = 5A
×
8
Ω
= 40 V. If you try to increase the
voltage above this point, the crossover point is reached, and the operation mode
automatically switches to CC mode. To maintain CV mode, increase the current
limit.
Next a load resistance (R
L
) of 5
Ω
is connected to the output terminals of the power
supply. The output voltage and output current are set to 30 V and 5 A, respectively.
In this case, Rc = 30 V/5 A = 6
Ω
. Since, 5
Ω
is less than 6
Ω
(R
L
< Rc), the
operation mode is CC. If you want to increase the current in CC mode, the current
can be increased up to the current defined by the following equation: Is = Vs/R
L
.
Substituting the values, we obtain Is = 30 V/5
Ω
= 6 A. If you try to increase the
current above this point, the crossover point is reached, and the operation mode
automatically switches to CV mode. To maintain CC mode, increase the voltage
limit.