Heinzinger electronic GmbH
Phone: +49 (0) 8031 2458 0
www.heinzinger.com
Anton-Jakob-Str. 4, 83026 Rosenheim
Fax: + 49 (0) 8031 2458 58
Germany
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ERS COMPACT
The same occurs with a positive load step, i.e. low load to high load. There the output collapses for a moment.
The amplitude of the overshoot resp. collapse depends on the device model, the currently adjusted output voltage
and the capacity on the DC output and can thus not be stated with a specific value.
Depictions:
Example for neg. load step: the DC output will rise
above the adjusted value for a short time. t = transient
time to settle the output voltage.
Example for pos. load step: the DC output will collapse
below the adjusted value for a short time. t = transient
time to settle the output voltage.
3.3.2
Current regulation / constant current / current limiting
Current regulation is also known as current limiting or constant current mode (
CC
).
The current in the DC terminal of the device is held constant once the output current (source mode) to the load resp.
the current consumed from the load (sink mode) reaches the adjusted limit. Then the device automatically switches
to CC. In source mode, the current flowing from the power supply is only determined by the output voltage and
the load’s true resistance. As long as the output current is lower than the adjusted current limit, the device will be
either in constant voltage or constant power mode. If, however, the power consumption reaches the set maximum
power value, the device will switch automatically to power limiting and set voltage and current according to P = U * I.
While the DC power stage is switched on and constant current mode is active, the condition “CC mode active” will
be indicated on the graphics display by the abbreviation
CC
and this message will be passed as a signal to the
analog interface, as well stored as status which can also be read as via digital interface.
3.3.2.1
Voltage overshootings
In certain situations it’s possible that the device generates a voltage overshooting. Such situations are when the
device is in CC, with the actual voltage being unregulated, and either a jump in the current set value is initiated
which would bring the device out of CC or when the load is suddenly cut from the power supply by an external
means. Peak and duration of the overshooting aren’t exactly defined, but as rule of thumb it shouldn’t exceed a
peak of 1-2% of the rated voltage (on top of the voltage setting) while the duration mainly depends on the charging
state of the capacities on the DC output and also the capacity value.
3.3.3
Power regulation / constant power / power limiting
Power regulation, also known as power limiting or constant power (
CP
), keeps the
DC power constant if the current flowing to the load (source mode) resp. the current
from the source (sink mode) in relation to the voltage reaches the adjusted limit
according to P = U * I (sink mode) resp. P = U² / R (source mode).
In source mode, the power limiter then regulates the output current according to
I = sqr(P / R), where R is the load’s resistance.
Power limiting operates according to the auto-range principle such that at lower
voltages higher current can flow and vice versa, always in order to maintain constant
power within the range P
N
(see diagram to the right)
.
While the DC power stage is switched on and constant power mode is active, the
condition “CP mode active” will be indicated on the graphics display by the abbre-
viation
CP
, as well stored as status which can also be read as a status message
via digital interface.