LNK 306

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We are using the LNK 306 as we require up to 200mA current to drive leds and a voltage regulator ic to drop the 12volts down to 5v to provide a small current to recharge a battery, nominal current we require is around 150mA . we are using the circuit given on page 4 of the 302-304-306.pdf however as soon as the current reaches 120mA we get a pulsating effect with the leds pulsating at a frequency of around 1 hz. The leds are 3 in series with a 75 ohm resistor and this is in parallel with 2 leds in series with a 300 ohm resistor. if we apply a 12 dc power supply to the circuit -at the output of the lnl306 - it shows we are taking 150mA which is correct. Our R&D team have spent much time looking for a solution but have not been able to determine the cause.
Hi there, Your application is a typical application of Link switch and it should work without fluctuation in output voltage. Your question shows that your board cannot provide more than 120mA and output drops and goes to restart again at 1Hz freqency (every 1 second). There could be some mis-selection of component in your design. If you may send the schematics or PI Expert Excel sheet of your design we could provide the changes you need in your circuit. Best regards, PI-Janeway