2.3 Overvoltage protection

n

n

n

n

n

n

n

The overvoltage protection circuit is built-in and comes into effect

at 115 - 140% of the rated voltage. The DC input voltage should

be shut down if overvoltage protection is in operation. The mini-

mum interval of DC recycling for recovery 2 to 3 minutes ( ).

The recovery time depends on input voltage.

By detecting overvoltage condition between +V and -V, overvoltage

protection circuit comes into effect at 115 - 140% of the rated

voltage.The DC input voltage should be shut down if overvoltage

protection is in operation. The minimum interval of DC recycling

for recovery 2 to 3 minutes ( ).

The recovery time depends on input voltage.

Please note that unit's internal components may be damaged if

excessive voltage (over rated voltage) is applied to output termi-

nal of power supply. This could happen when the customer tests

the overvoltage performance of the unit.

The output voltage is adjustable by external potentiometer.

When the output voltage adjustment is not used, open the TRM

pin.

The over voltage protection circuit comes into effect when the out-

put voltage is set too high.

Output voltage is increased by turning potentiometer clockwise

and is decreased by turning potentiometer counterclockwise.

The wiring to the potentiometer should be as short as possible

and connected to the remote sensing pins (+S and -S).

The temperature coefficient varies depending on the type of re-

sistor and potentiometer.

It is recommended that the following types be used.

Resistor ...........Metal film type. coefficient of less than ±100ppm/

Potentiometer..Cermet type, coefficient of less than ±300ppm/

2.4 Adjustable voltage range

l

l

Single Output

Multiple Output

Remarks:

2.5 Remote ON/OFF

nThe ground terminal of remote ON/OFF circuit is connected with

-V input terminal.

Between RC and -V input: Output voltage is ON at ”Low” level or

short circuit (0 - 1.2V)

Between RC and -V input: Output voltage is OFF at ”High” level

or open circuit (2.4 - 5.5V)

(Connection example)

ZU/ZT-41

ZU15 ZU25

Fig.2.1 Overcurrent protection characteristics

Fig.2.2 Connection devices outside the power supply

Table 2.1 Devices outside the power supply (Adjustable ±5%)

No.

Output

voltage

1

2

3

4

5

3V

5V

12V

±12V

±15V

VR

1K

1K

5K

5K

5K

R1

470

100

270

10K

10K

The constant value of devices outside the power supply (Unit: )

R2

150

270

2.7K

3.9K

2.7K

or

or

Transistor

IC

Relay

When RC terminal is ”Low” level, fan out current is 1mA typ.

When Vcc is applied, use 5V

Vcc

24V. When remote ON/OFF

function is not used, please short between RC and -V input.

2.6 Isolation

nFor a receiving inspection, such as Hi-Pot test, gradually increase

(decrease) the voltage for the start (shut down). Avoid using Hi-

Pot tester with the timer because it may generate voltage a few

times higher than the applied voltage, at ON/OFF of a timer.

ZU/ZT

Instruction

anual

M

DC-DC Converters PCB Mount type

October 08, 2013