Delta Electronics Series S48SS Features Descriptions, Over-Current Protection, Remote ON/OFF

FEATURES DESCRIPTIONS

Over-Current Protection

The modules include an internal output over-current protection circuit, which will endure current limiting for an unlimited duration during output overload. If the output current exceeds the OCP set point, the modules will automatically shut down (hiccup mode).

The modules will try to restart after shutdown. If the overload condition still exists, the module will shut down again. This restart trial will continue until the overload condition is corrected.

Over-Voltage Protection

The modules include an internal output over-voltage protection circuit, which monitors the voltage on the output terminals. If this voltage exceeds the over- voltage set point, the module will shut down and latch off. The over-voltage latch is reset by cycling the input power or by togging the ON/OFF signal for one second.

Output Voltage Adjustment (TRIM)

To increase or decrease the output voltage set point, the modules may be connected with an external resistor between the TRIM pin and either the Vo+ or Vo -. The TRIM pin should be left open if this feature is not used.

Vo(+)
Trim	Rtrim-down
Vo(-)

Figure 16: Circuit configuration for trim-down (decrease output voltage)

If the external resistor is connected between the TRIM and Vo+ pins, the output voltage set point decreases. The external resistor value required to obtain a percentage of output voltage change △Vo% is defined as:

Rtrim − down = 222.732 − 248.4∆Vo − 3.32[ΚΩ] 12∆Vo + 0.07

Ex. When trim-down –10% (12V X 0.9 =10.8V)

Rtrim − down = 222.732 − 248.4 × 0.1 − 3.32 = 152.50[ΚΩ] 12 × 0.1 + 0.07

Vo(+)

Trim

R trim-up

Vo(-)

Figure 17: Circuit configuration for trim-up (increase output voltage)

If the external resistor is connected between the TRIM and Vo - the output voltage set point increases. The external resistor value required to obtain a percentage output voltage change △Vo% is defined as:

Rtrim − up =	25.668	− 3.32[ΚΩ]
	12∆Vo − 0.07

Ex. When trim-up +10% (12V X 1.1 = 13.2V)

Rtrim − up =	25.668	− 3.32 = 19.39[ΚΩ]
	12 × 0.1 − 0.07

Care should be taken to ensure that the maximum output power of the module remains at or below the maximum rated power.

Remote ON/OFF

The remote on/off feature on the module can be either negative or positive logic. Negative logic turns the module on during a logic low and off during a logic high. Positive logic turns the modules on during a logic high and off during a logic low. Remote on/off can be controlled by an external switch between the on/off terminal and the Vi(-) terminal. The switch can be an open collector or open drain. If the remote on/off feature is not used, please short the on/off pin to Vi(-) for negative logic and let the pin open for positive logic.

Vi(+)	Vo(+)
ON/OFF	Trim
Vi(-)	Vo(-)

Figure 18: Circuit Configuration for Remote ON/OFF

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