Specifications

12
1-800-927-9474
14-2
Applications Manual
EMC
EMC performance is guaranteed when the VI-IAM is used in conjunction with Vicor converters
within the permissible power rating and in accordance with the recommended installation
procedure (Figure 2, page 14-4). The capacitor shown across the input of the converter, bypass
capacitors and series resistors shown on the –In and +In of the DC-DC converters to ground
are required to meet EMC specifications. The capacitors should be Y-rated (interference
suppression). These capacitors have high voltage breakdown ratings to meet the isolation
characteristics of the module’s input to baseplate specification plus self-healing properties, and
have safety agency approvals.
Input Reverse Polarity Protection
A zener diode in the EMC filter provides reverse polarity protection when used with a current
limiting device external to the VI-IAM. The characteristics of the recommended input line
fuses permit normal full load operation with protection in the event of a reverse polarity;
see table below.
Input Transient Protection
A zener diode, inductor and capacitor in the EMC filter protect against short term transients.
Transient voltages that persist beyond these limits are dropped across an N-channel enhancement
FET, Q1. It is necessary that the FET be kept in saturation mode during normal operation.
Thus it is necessary to connect the DC-DC converters’ Gate Out to the VI-IAM’s Gate Out to
charge pump the gate of the FET to a voltage in excess of its source. In the case where multiple
DC-DC driver modules are connected to one VI-IAM, an external charge pump through the
parallel pin (connected to the gate of the FET) must be added to ensure that the FET remains
enhanced in the event Gate Out enhancement is lost (Figure 3, page 14-4). The additional
circuitry, C2, D1 and D2 are added externally to charge pump through the parallel pin.
Shutdown of the DC-DC converters is accomplished by saturating Q2 during an input
over-voltage to prevent possible damage to the converters. The VI-IAM will automatically
restart when the input overvoltage is reduced to within the input voltage range.
If the long term transient withstand specifications are exceeded, the recommended external fuse
will clear.
Input Voltage Recommended Fuse
24V 20A/32V (AGC-20)
24V “W” 20A/36V (AGC-20)
48V 20A/60V (3AB-20)
48V “N” 20A/80V (3AB-20)
300V 5A/250V Bussman PC-Tron
28V 20A/250V (3AB-20 or F03A, 125V, 20A)
270V 5A/250V Bussman PC-Tron or F03A, 250V, 4A