TDK iFA Series - page 12

Advance Data Sheet: Maxeta

iFA Series

iFA Advance Datasheet 6/6/2005

℡

(877) 498

0099

12/18

Operating Information:

Output Over-Current Protection: The

power modules are equipped with current

limit, over-current slow hiccup, and over-

current trip fast hiccup mode protection.

These three protection mechanisms

safeguard the module during output

overload and short circuit conditions. During

overload conditions, the power modules

protect themselves by first entering a current

limit operation mode by lowering the module

output voltage. The relatively long off

duration slow hiccup mode current

protection circuit is triggered once the

filtered peak switch current reaches the

preset value. The modules will operate

normally once the output current returns to

the specified operating range. The fast

over-current trip protection is used to protect

against short circuit or switch shoot-through

conditions. It is a non-latch fast acting

protection circuit. The triggering threshold is

normally set quite high.

Over-Current Adjustment: The over-

current limit set point cannot be adjusted

externally in this design.

Input Over-voltage Protection:

The power

modules have an internal protection circuit

to help guard against application of over

voltage at the input of the power module.

The modules shut down to protect

themselves when the input line voltage

exceeds 36Vdc. When the input over-

voltage condition is removed, the unit will

auto restart and operate normally.

Input Under-voltage Lockout: The power

modules also feature an input under voltage

lockout circuitry that ensures that the power

module is off at low input voltage levels.

The power module will operate normally

when the input voltage returns to the

specified range.

Output Over-Voltage Protection: The

power modules have a protection circuit,

independent of the main PWM control loop

that reduces the risk of over voltage

appearing at the output of the power module

during a fault condition. If there is a fault in

the main regulation loop, the over voltage

protection circuitry will latch the power

module off once it detects the over-voltage

condition as specified on the electrical data

page. To remove the module from the

latched condition, either turn the input power

off and back on or reset the remote ON/OFF

pins providing that over-voltage conditions

have been removed. The reset time of the

ON/OFF pins should be 500ms or longer.

Output Over-Voltage Adjustment: The

output over-voltage set point cannot be

adjusted externally in this design.

Output Under-Voltage Warning: The iFA

series power module has internal circuitry to

protect against output under-voltage

conditions. If an under-voltage condition is

present on the output, the module will signal

this condition using the “Power Good” pin.

There is a delay between the under-voltage

condition appearing at the module output

and the module switching the “Power Good”

pin to high impedance.

Thermal Protection: When the power

module exceeds the maximum operating

temperature, it will turn-off to protect itself

against thermal damage. The module will

auto restart as soon as it cools down below

the recovery temperature.

Thermal Warning: There is no thermal

warning feature for this design.

Remote On/Off: The iFA series power

modules have two remote on/off pins, which

are isolated from the input side as well as

the output side. To control the power module

from the input side, the user must supply a

switch between the Vin(-) terminal and the –

ON/OFF terminal of ON/OFF pins. A 15KΩ

external resistor with 0.25W or more power

rating is recommended to connect between

the Vin(+) terminal and the +ON/OFF

terminal. The maximum allowable leakage

current of the switch is 50uA. The maximum

current sinking capability of the ON/OFF

terminal is 5mA or less. The current required

to maintain the module ON status must be

greater than 1mA.