Foldback Protection; Setting The Foldback Protection; Resetting Activated Foldback Protection; Output On/Off Control - TDK-Lambda GENESYS GEN 2400W Series Technical Manual

5.5 FOLDBACK PROTECTION

FOLDback protection will shut down the power supply output if the load current exceeds the Output current limit
setting level. This protection is useful when the load circuitry is sensitive to an overcurrent condition.
5.5.1

Setting the FOLDback Protection

To arm the FOLDback protection, the FOLD button should be pressed so that the FOLD LED illuminates. In this
condition, a transition from Constant-Voltage to Constant-Current mode will activate the FOLDback protection.
Activation of the FOLDback protection disables the power supply output, displays "Fb" on the VOLTAGE meter
and causes the ALARM LED to blink.
5.5.2

Resetting Activated Foldback Protection

There are four methods to reset an activated Foldback protection.
1. Press the OUT button. The power supply output is then enabled and the Output voltage and current will
return to their last setting. In this method, the FOLDback protection remains armed, therefore if the load
current is higher than the Output current limit setting, the FOLDback protection will be activated again.
2. Press the FOLD button to cancel the FOLDback protection. The power supply output will be disabled and
the VOLTAGE meter will display "OFF". Press the OUT button to enable the power supply output.
3. Turn the power supply output OFF and then ON using the SO control (refer to Section 5.7). In this method
the FOLDback protection remains armed, therefore if the load current is higher than the Output current limit
setting, the FOLDback protection will be activated.
4. Turn the power supply OFF using the AC ON/OFF power switch, wait until the front panel display turns OFF,
then turn the unit back ON using the AC ON/OFF power switch. The power supply output is then enabled
and the Output voltage and Output current will return to their last settings. In this method, the FOLDback
protection remains armed, therefore if the load current is higher than the Output current limit setting, the
FOLDback protection will be activated again.

5.6 OUTPUT ON/OFF CONTROL

The Output ON/OFF Enables or Disables the power supply output. Use this function to make adjustments to
either the power supply or the load without shutting off the AC input power. The Output ON/OFF can be
activated from the front panel using the OUT button or from the rear panel J1 connector SO or Enable/Disable
pins. The front panel OUT button can be pressed at any time to Enable or Disable the power supply output.
When the output is disabled, the Output voltage and Output current fall to zero and the VOLTAGE meter
displays "OFF".

5.7 OUTPUT SHUT-OFF (SO) CONTROL VIA REAR PANEL J1 CONNECTOR

Contacts J1-2, -3 and -15 (Figure 4-3, Item 5) serve as Output Shut-Off (SO) terminals. The SO terminals accept
a 2.5V to 15V signal or Open-Short contact to Enable or Disable the power supply output
The SO function is activated ONLY when a transition from ON to OFF is detected (after applying AC power to
the unit). Thus, in Auto-Restart mode the output will be enabled after applying AC input power; even if the SO is
OFF (as no transition from ON to OFF occurred). After an ON to OFF transition it is detected, the SO will enable
or disable the power supply output according to the signal level or the short/open applied to J1.
This function is useful for connecting power supplies in a "Daisy-chain" (refer to Section 5.16). The SO control
can also be used to reset the OVP and FOLDback Protection (refer to Section 5.3 and 5.5 for details). When the
unit is shut-off by a J1 signal, the VOLTAGE display will show "SO" to indicate the unit state. J1 contact 15 is the
SO signal input and contacts 2 and 3, IF_COM, are the signal return (connected internally).
Contacts J1-2, -3 and -15 are optically isolated from the power supply output.
The SO control logic can be selected by the rear panel SW1 Setup switch. Refer to Table 5-2 for SW1 setting
and SO control logic.
SW1-5 Setting
DOWN (default)
UP
SO signal level Power Supply
J1-2 (3), J1-15
2 - 15V or Open
0 - 0.6V or Short
2 - 15V or Open
0 - 0.6V or Short
Table 5-2: Shut-Off (SO) Logic Selection
83-517-000 Rev. A
Display
Output
ON Voltage/Current
OFF
OFF
ON
Voltage/Current
45
"SO"
"SO"