TDK iFA Series manual 15/18

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Advance Data Sheet: MaxetaTM iFA Series

The output voltage can also be adjusted within the same range by applying external voltage at the trim pin via a buffer. In this case, Vo_d can be approximately determined by the following formula:

Vo_d Trim Terminal Voltage × Vo,nom

Contact Innoveta for more details on the voltage trim using an external source.

The maximum power available from the power module is fixed. As the output voltage is trimmed up, the maximum output current must be decreased to maintain the maximum rated power of the module.

As the output voltage is trimmed, the output over-voltage set point is not adjusted. Trimming the output voltage too high may cause the output over voltage protection circuit to be triggered.

Remote Sense: The power modules feature remote sense to compensate for the effect of output distribution drops. The maximum voltage allowed between the output power terminals and output sense terminals is 0.5V. If the remote sense feature is not being used, the sense(+) terminal should be connected to the Vo(+) terminal and the sense(-) pin should be connected to the Vo(-) pin.

The output voltage at the Vo(+) and Vo(-) pins can be increased by either the remote sense or the output voltage adjustment feature. The maximum voltage increase allowed is the larger of the remote sense range or the output voltage adjustment range; it is not the sum of both.

As the output voltage increases due to the use of the remote sense, the maximum output current must be decreased for the power module to remain below the maximum rated power of the module.

Power Good (Optional): Normal or abnormal operation of the power module can be monitored using the power good signal. The power good pin provides an open collector signal referenced to the output sense (-) pin

that is pulled low during normal operation of the power module. The power good circuitry will pull the power good pin below 1V while sinking a maximum sink current of 5mA. The maximum allowed voltage to the pin is 35V. In order for the power good to pull low, the following conditions must all be met:

-None of the power module’s protection features have been tripped; the protection features include over-voltage, over- current, and over-temperature protection.

-The internal bias voltage is present.

-The internal PWM drive signal is present.

-The output voltage is approximately between 90% and 115% of Vo,nom.

When these conditions are not met, the maximum voltage that will appear at the output of the power good pin can be up to 50V. The typical impedance from the power good pin to ground is greater than 500KΩ.

Power Good signal may give invalid signal during the following conditions:

-Operation of over-current protection

-Light load condition at parallel operation

-Dynamic load operation

Parallel Operation (Optional): The iFA series power modules are capable of sharing the load current when multiple units are connected in parallel. The load sharing technique used is the democratic load share scheme. By connecting the PC (or Ishare) pin of each power module with single wire, the output load current can be equally drawn from each module. The voltage at PC pin will range from 0 to 2V, referenced to the output side sense(-). All modules in parallel should be referenced to the same ground with good ground plane.

By setting the output voltage accuracy of each power module in a parallel operation to within ±1%, the load share circuit within the module will force the load current to be shared equally among the multiple modules within ±10% accuracy from 50% to 100% of the rated load. The maximum output power rating of each module shall not be exceeded.

©2005 TDK Innoveta Inc.

 

￿ (877) 498-0099

iFA Advance Datasheet

6/6/2005

15/18

 

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Contents Advance Data Sheet MaxetaTM iFA Series TDK Innoveta Inc Product OfferingMechanical Specification Heatsink Offering Pin AssignmentAbsolute Maximum Ratings Input CharacteristicsIFA24021A280V- 000 through 026 28V, 21.5A, 602W Output Electrical DataTypical Efficiency vs. Input Voltage and Load at Ta=25 C Electrical CharacteristicsCh Vo Ch Io With 0.1A/uS Vin=nominal Ch.1 Vo Ch Io Input Output Thermal PerformanceThermal Management 11/18 Operating Information ON/OFF Control from Input Side Figure Trim Down Connection 15/18 Quality ReliabilityInput/Output Ripple and Noise Measurements Safety ConsiderationsTDK Innoveta Inc IFA Advance Datasheet 6/6/2005 Warranty