Voltage Control

The operation mode “Voltage Control” enables an LED to be driven by voltage control.

In this mode the maximum output current is 1.2 A up to an LED voltage of 12 V. Above 12 V the user must consider derating, as otherwise the module may switch off due to overtemperature if the power exceeds 14.4 W.

In this mode a set voltage is specified that is continuously controlled. The output current depends on the connected load. The output current can increase to 200% of the target current (limit current) in the CoE index 0x8000:02. If the resistance of the connected load is too low, so that the output current would have to rise to more than 200% of the set limit current in order to keep the output voltage constant at the specified value, the terminal switches the output off.

In this operation mode, it is possible to configure the trigger input as an enable input so that it can be used as an external switch. An output can then only be actuated with a prespecified signal at the trigger input. More detailed information and commissioning can be found in the chapter Hardware enable.

The specific parameters for setting the LED output as a voltage-controlled output are described below.

  1. Nominal/limit current of the LED in index 0x8000:02 “Target current” in the unit mA
  2. Input voltage in index 0x8000:03 “Supply voltage” in the unit 0.01 V
  3. Set the operation mode in the CoE directory in the index 0x8004:01 to “Voltage Control”
    4. Voltage Control 1:
    Operation mode setting “Voltage Control”
  4. Set Predefined PDO Assignments to “Voltage control (with info data)”
    5. Voltage Control 2:
    PDO setting “Voltage control (with info data)”
  5. Specify the set voltage in the unit 0.01 V (max. UIN - 0.5 V) via “DOX Voltage” → “Output” Voltage. The limit voltage of the output is specified in the unit 0.01 V in the CoE index 0x8000:04 “Supply voltage”. If the set voltage specified in the PDO is greater than the limit voltage, the maximum limit voltage will nevertheless be output (without warning).
  6. Check under “DOX Status” → “Status” whether the “Ready to activate” bit is 1.
  7. Activate the control under “DOX Control” → “Control” via the “Enable” bit.
  8. Switch on the LED output under “DOX Control” → “Control” by activating the “Output” bit.
Voltage Control 3:
Activating the output in the operation mode “Voltage control”