Output return path using current sense pin and ground

2 posts / 0 new

Hi,

Using the PI expert tool for CC/CV of 5V/2.2A the circuit was simulated and optimized online, but the return path RTN across the output is the part for which I'm unable to understand, as per the datasheet it needs to be connected in order to achieve current regulation, we need current regulation but the return path is connected across it. I need a way to connect to ground and RTN using a 0-ohm resistor so that I can change as per my requirements later on. Can some one help on how to achieve this ASAP.
I have attached the file, PFA.

첨부 파일Size
USB-5V_2.2A.pdf2.29 MB

Hello Siddaraju,

Thank you for considering Power Integrations.

In Innoswitch3, current regulation is achieved by sensing the output current through a sense resistor, then connecting this resistor across IS pin and the IC GND. The resistor voltage is maintained at around 35mV (please refer to datasheet for the exact range of values). In your example, 35mV/15.5mohm = 2.25A, meaning the circuit will regulate at 2.25A. If the value of the sense resistor is changed, then the current regulation will also change accordingly.

This configuration is inherent to InnoSwitch3, so a different resistor, like a 0-ohm resistor, cannot be used if your goal is to get 2.2A constant current regulation.

May I know what are your requirements such that you have to use a 0-ohm resistor?

Thanks.