LNK306 Enable
Dear Sir,We have designed a 12V .3A power supply using a LNK306 as I show in the picture. This circuit works fine but the consumption without load is quite high (1.2mA @ 300V). We would like to disable the system with a processor when it's not used. You know how we can implement a low-cost disable referenced to 0V?Thank you.
Comments
Thank you for your quick response.With Bp and S pins shorted the output voltage falls but the LNK continues to consume (2mA.avg).The 5.8V regulator try to load the BP output?
The LNKSwitch still is active. It is not completely OFF. This family of devices does not have a feature for fully externally turn them OFF
PI-Wolf,
Do you happen to know what the current consumption would be if instead of placing the part into UVLO, as a disable, you instead pull the FB pin above the 49uA via a resistor to BP? Or is pulling BP to source the only advisable way of disabling the output?
Hello snyderjn,
If you pull the FB pin above 49uA, there will be two current flow through the IC. the Total current consumption is the sum of IS1 and IDSS when FEEDBACK pin voltage is ≥2 V (MOSFET not switching).
Depend on how you pull up FB and how high you pull it. there will also have some dissipation on the feedback divided network(two resistor).
The consumption will vary with the input voltage and the size of the IC(LNK302 or 4, 5,6). You will find the information in our LNK-TN datasheet.
Best Regards
You can use the bypass pin to stop the switching. Short the bypass pin to SOURCE pin and the controller will stop running