iHP Manual 80 | P a g e
4.5.2.1 ACS Protection Modes
When the supply is in ACS 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. Please refer to Section 8 on how to clear the fault and power up the module after fault.
4.5.2.1.1 ACS Protection: Constant Voltage Clamp
There are conditions that can exist when the output voltage will be greater than the VREF level (B1h):
Fix load resistance and user increases the IPROG input.
Fix IPROG input setting and load resistance increases.
When module output voltage reaches the VREF level, the module will enter constant voltage clamp. This will
protect the system from continuous increase in output voltage. There will be no fault reporting during this
condition. To enter again to ACS, the user needs to decrease the IPROG input or decrease the load resistance.
For module software v04.10.00 and above, the 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 cannot be changed and is set to the nominal output voltage.
4.5.2.1.2 ACS Protection: Over Current Protection and Short Circuit Protection
During ACS, over current protection 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 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.
4.5.2.1.3 ACS Protection: Over Voltage Protection (OVP)
Over voltage protection level during ACS will be based on the OV Fault Limit Multiplier (48h) and VREF (B1h)
setting.
OV Level = (48h OV_FAULT_LIMIT_MULTIPLIER) x (B1h VREF)
4.5.2.1.4 ACS Protection: Under Voltage Protection (UVP)
During ACS operating mode, under voltage protection is not functional
4.5.3 Module Grouping for Series or Parallel Connection Analog Operation
Modules can be operated in Series or Parallel connection during analog mode. Below are list of possible series
or parallel connections:
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