EPR-12 Datasheet, PDF (11/40 Pages) Power Integrations, Inc. – Engineering Prototype Report for EP-12 - 145 W PC Forward Converter with TOP247 and 10 W 5 V Output Standby Flyback with TNY266

01-Feb-05
EPR-12 – PC Forward Converter with Standby Flyback Power Supply
enable the TOP247 via its X pin. If the output comes up into regulation before C19
completely discharges, Q3 is sustained on through R28 and the converter remains
running. Upon loss of regulation, Q3 will turn off and the converter will shut off. Toggling
the ON/OFF input will allow the converter to retry operation.
When the ON line is open, it is internally pulled up to the +5 V standby and the main
converter remains in the inhibit state. The +5 V standby is always operating provided
there is sufficient AC input to the supply. By connecting the ON line to output return, the
main supply will turn on, provided there is sufficient input voltage and there is no fault
condition. If there is a fault then the supply will latch off. A retry is accomplished by
simply toggling the ON line.
Note: If the remote ON line is connected to output return (main power enabled) while
turning on AC into the supply, the main converter will automatically turn on. However, if
AC is brought up too slowly (i.e. adjusting a variac), the supply will not turn on and the
ON line will have to be toggled to turn on the supply. The output interconnect board
provided has the ON line already connected to an ON/OFF switch for manual
ON/OFF control via the ON line.
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