LINFINITY SG3540
The SG1540 is an integrated circuit designed to efficiently provide start-up power from a high-voltage DC bus to a PWM control circuit in a switching power supply. When used on the primary side, it reduces start-up current to less than 1mA and allows any standard PWM control circuit to be used as a primary-side controller.| Part No. | SG3540 |
|---|---|
| Datasheet | SG3540 Download |
| Manufacturer |  LINFINITY |
| Description | OFF-LINE START-UP CONTROLLER |
| Buy | Stock & Price |
DESCRIPTION
When used to power a controller on the secondary side, it efficiently eliminates the need for a heavy 50/60Hz line transformer with its associated low frequency magnetic fields. The circuit consists of three sections: a micropower bandgap comparator/power switch referenced to 2.5 volts which isolates the start-up capacitor from its load; a high frequency square-wave oscillator with 200mA totem-pole output for driving an isolation transformer; and a second bandgap comparator with latching crowbar to protect against overvoltage faults while starting or running. The SG1540 is specified for operation over th
