iHP Manual 70 | P a g e
To change module output current, user needs to send below B2h (IREF) command to the module.
< Data is the Set Current>
*Before writing to the module, please ensure that the Module Command Write Protect (10h) is disabled.
* Please refer to Section 5.2 for Module User Configurable Parameters or Appendix B.2 Module Command
The user can program the module’s output current within 0% to 100% of the nominal output current. Setting
the IREF value beyond the acceptable range, but not to 0A, the module will trigger a Status CML fault and will
retain the existing value. Setting the IREF value to 0A will cause the module to enter to standby mode. To
enable again the module, set IREF to an acceptable range.
4.4.2.1 DCS Protection Modes
When the supply is in DCS mode, the supply limits the current to the IREF value and the voltage is limited by
the VREF value. Secondary output protection is provided in rare load conditions by the OC Fault Level and the
OV Fault Level.
4.4.2.1.1 DCS Protection: Constant Voltage Clamp
There are conditions that can exist when the output voltage will be greater than the VREF level (B1h)
Fixed load resistance and the user increases the IREF setting
Fixed IREF setting and load resistance increases.
When module output voltage reaches the VREF level, the module will enter constant voltage mode. This will
protect the module from continuous increase in output voltage. There will be no fault reporting during this
condition. To enter again to DCS, the user needs to decrease the IREF setting or decrease the load resistance.
For module software v04.10.00 and above, user can update the Constant Voltage Clamp from nominal voltage
down to 5% of the nominal voltage of the module via Module Command B1h. For module software below
v04.10.00, constant voltage clamp is fixed to the nominal output voltage.
4.4.2.1.2 DCS Protection: Over Current Response and Short Circuit Protection
During DCS, over current response will be fix to “Latch type” (52h). OC level will be based on Module
Command 4Dh OC_FAULT_LIMIT_MULTIPLIER setting.
Module Command 4Dh OC_FAULT_LIMIT_MULTIPLIER range is 50% to 105%
The module will shut down when the output current reaches the OC level and a fault status will be reported.
With Vo (VREF) below or equal to the nominal voltage, the latch level setting value is
Latch Current Level = (Inominal) * (OC_FAULT_LIMIT_MULTIPLIER)
Note that the latch setting level will NOT be reflected to IREF (Module command B2h). Latch level can be
determined by computation as stated above.
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