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LNK302 dummy load ?

Posted by: treez on 05/01/2022

Hi,

We want to do a 5V, 100mA circuit from 100-265VAC with LNK302.

The datasheet says a dummy load is required if an opto isnt used...it shows 3k3 being used when vout = 12V.....so , thats 44mW....so presumably, if we make output = 5v

, then a 560R dummy load is required.?

Also, the datasheet says the minimum on time of LNK302  is 360ns..........also, that the LEB is 170ns...so does it mean that the minimum on time is actually 360ns + 170ns?

Comments

Submitted by PI-Hueka on 05/03/2022

Hi treez, 

Thank you for your interest in using Power Integrations product in your design. 

For your given output requirement of 5 V and 100 mA, we suggest using LNK304P/G/D since it is the product that matches your requirement, it is rated to maximum current output up to 170 mA. Your preferred device, LNK302 is capable of up to 80 mA only, this is stated in the datasheet Output Current Table on page 1. 

For the pre-load of output 5 V and 100 mA, it should be calculated to have a minimum load of 3 mA. The pre-load should have a maximum value of around 1.7 kΩ. 

The Limiting Edge Blanking Time (tLEB) starts with the specified Minimum On Time tON(MIN). The Minimum On Time remains the same as stated on the datasheet, 360 ns typical.  

We hope this resolves your inquiry. Thank you.