Delta Electronics DNT04 manual Features Descriptions CON

FEATURES DESCRIPTIONS

Remote On/Off

The DNT series power modules have an On/Off pin for remote On/Off operation. Both positive and negative On/Off logic options are available in the DNT series power modules.

For positive logic module, connect an open collector (NPN) transistor or open drain (N channel) MOSFET between the On/Off pin and the GND pin (see figure 26). Positive logic On/Off signal turns the module ON during the logic high and turns the module OFF during the logic low. When the positive On/Off function is not used, leave the pin floating or tie to Vin (module will be On).

For negative logic module, the On/Off pin is pulled high with an external pull-up resistor (see figure 27). Negative logic On/Off signal turns the module OFF during logic high and turns the module ON during logic low. If the negative On/Off function is not used, leave the pin floating or tie to GND. (module will be On)

Vin Vo

ION/OFF

On/OffRL

Q1

GND

Figure 26: Positive remote On/Off implementation

Vin Vo

Rpull-

up

ION/OFF

On/OffRL

Q1

GND

Figure 27: Negative remote On/Off implementation

Over-Current Protection

To provide protection in an output over load fault condition, the unit is equipped with internal over-current protection. When the over-current protection is triggered, the unit enters hiccup mode. The units operate normally once the fault condition is removed.

DS_DNT04SIP3A_09262007

FEATURES DESCRIPTIONS (CON.)

Over-Temperature Protection

The over-temperature protection consists of circuitry that provides protection from thermal damage. If the temperature exceeds the over-temperature threshold the module will shut down. The module will try to restart after shutdown. If the over-temperature condition still exists during restart, the module will shut down again. This restart trial will continue until the temperature is within specification.

Output Voltage Programming

The output voltage of the DNT can be programmed to any voltage between 0.75Vdc and 3.3Vdc by connecting one resistor (shown as Rtrim in Figure 28) between the TRIM and GND pins of the module. Without this external resistor, the output voltage of the module is 0.7525 Vdc. To calculate the value of the resistor Rtrim for a particular output voltage Vo, please use the following equation:

⎡	21070	⎤
Rtrim = ⎢		− 5110⎥Ω
⎣Vo − 0.7525		⎦

For example, to program the output voltage of the DNS module to 1.8Vdc, Rtrim is calculated as follows:

⎡	21070	⎤
Rtrim = ⎢		− 5110⎥Ω = 15KΩ
	− 0.7525
⎣1.8		⎦

DNT can also be programmed by apply a voltage between the TRIM and GND pins (Figure 29). The following equation can be used to determine the value of Vtrim needed for a desired output voltage Vo:

Vtrim = 0.7 − 0.1698× (Vo − 0.7525)

For example, to program the output voltage of a DNT module to 3.3 Vdc, Vtrim is calculated as follows

Vtrim = 0.7 − 0.1698× (3.3 − 0.7525) = 0.267V

Vo

RLoad

TRIM

Rtrim

GND

Figure28: Circuit configuration for programming output voltage using an external resistor

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