62
Considerations
During the operation of the power supply, various problems may occur because of the
difference in connected loads, which will be introduced as follow respectively.
Capacitive Load
In most cases, the power supply will be stable for capacitive load of any size. Load
with large capacitor may cause ringing in the power supply’s transient response. It is
possible that certain combinations of load will result in output instability. And the
problem may be solved by properly decreasing the total load capacitance.
A large capacitor at the output terminals may cause the power supply to cross into CC
or unregulated mode momentarily when the output is enabled. The slew rate of the
output voltage will be limited to the current setting divided by the total load
capacitance (internal and external).
Signal
Internal
Capacitance
Internal
Load
Current
Slew Rate at No
Load and Full Scale
Current Setting
3662A 3000uF
0.65A
2V/msec
3663A 1440uF 0.3A
4V/msec
3664A 660uF
0.15A 6V/msec
Inductive Load
Inductive loads present no loop instability in constant voltage mode. In constant
current mode, inductive loads form a parallel resonance with the power supply’s
output capacitor. Generally this will not affect the stability of the power supply, but it
may cause ringing instantaneously when the power supply responds to the output..
Pulse Load
In some applications the load current varies within a large range. The constant current
circuit limits the output current. Some peak loading exceeding the current limit can be
obtained from the output capacitor. To stay within the specifications for the output, the
current limit should be set greater than the peak current expected or the supply may
go into CC mode or unregulated mode.
Reverse Current Load
An external source is not allowed to pump current into the supply. A reverse current
loading may risk the loss of regulation and the damage of the power supply.
Extending the output
The ARRAY 366XA provides corresponding outputs, and enables the power supply to
provide voltages or currents greater than its rated maximum outputs with different
connecting measures when needed.
