Output Turn-On Turn-Off Behavior
The turn-on and turn-off sequences are primarily controlled by three factors: the user-programmed
turn-on/turn-off delays, and the voltage and current priority mode settings.
The following table documents the output impedance setting for the turn-on and turn-off sequences.
You can specify either Low or High output impedance when operating in Voltage priority mode.
Models
Voltage Priority
Current Priority
All models
Impedance is user-selectable via
command
High impedance turn-on
High impedance turn-off
The following Output-On and Output-Off sequence descriptions are illustrated in the accompanying
flowchart.
Output-On Sequence
The internal power circuits are connected to the output by a solid-state switch. Upon the receipt of an
Output On command, the power supply waits for the duration of the user-programmed turn-on delay.
In voltage priority with LowZ, the power supply programs its internal circuits to a voltage of zero and
sets the current limits to their user-programmed values. In voltage priority with HighZ, the power
supply matches its internal voltage to the DUT voltage.
In current priority, the power supply also matches its internal voltage to the DUT voltage. This
ensures that when a source such as a battery is connected to the output, that there is no current
surge into the power supply from the DUT when the output is turned on.
The power supply's solid-state output switch is then closed, connecting the output to the internal
power circuits. The output voltage and current are programmed to their user-settings. The output
follows the slew rate setting.
Output-Off Sequence
Upon the receipt of an Output Off command, the power supply waits for the duration of the user-
programmed turn-off delay.
In voltage priority with LowZ, the power supply programs the voltage to zero. It then waits up to 250
ms to discharge any current from the DUT. It then programs the current limits to their minimum
settings. In voltage priority with HighZ, the power supply only programs the current limits to their
minimum settings.
In current priority, the power supply programs the current to zero. It then waits up to 250 ms to
discharge any current from the DUT.
The power supply's solid-state output switch is then opened, disconnecting the output from the
internal power circuits.
If you wish to program a voltage turn-off slew rate, you must set the slew rate and
program the output voltage to zero
before
you send the output off command.
4 Using the DC Power System
126
Keysight N69100 Series Operating and Service Guide
