Vicor Westcor PFC MegaPAC Power Factor Corrected AC-DC Switchers - Manual (Page 30)

UG:105 vicorpower.com Applications Engineering: 800 927.9474 Page 30
Output Sequencing
Using the MegaPAC's standard Input Interface Connector (J10) along with the
ConverterPAC's optional DC OK Option*, it is possible to implement unique output
voltage power up and power down sequences. Below is an example showing how this
may be done.
* DC OK Option is not available for VI-J00 dual output DualPACs
Requirement: 5 V must start before the 3.3 V output. If the 5 V output is lost, the 3.3 V
output must turn off.
The first step in meeting this requirement is to configure the 5 V ModuPAC with the
DC OK Option, which is indicated by a "D" designator in the M oduPAC's part number,
located on the top surface of each ModuPAC above the +Vout. Any ModuPAC that
has the DC OK option will also have the 4 pin J3 DC OK connector installed. To
order a ModuPAC with the DC OK option, please contact Westcor's customer service
department for assistance. The DC OK option monitors the output voltage of a given
ConverterPAC and provides a TTL logic signal depending on its output voltage.
Figure 15.
ModuPAC Pinout
Figure 16.
J3 DC OK Connector
J2 Pin 1
J3 pin 1 (DC OK Option)
+ Vout
- Vout
Vtrim Pot Adjust (Option)
4
3
2
1
J3
J3-4 Vcc
J3-3 Power Good
J3-2 Power Good Inverted
J3-1 Signal Ground
Pin
DC OK (Power Good)