Issue with ST1CC40 in eDesign Studio

[bhrishikesh]

Posted on February 17, 2016 at 18:49

I'm trying to design a constant current driver in eDesign Studio using the ST1CC40DR chip. I've set my output requirements to 4.8V and 1.2A and the input is 12V DC. With a 2% LED ripple current and 10% inductor ripple current, I was shown the inductor values of 33uH, input capacitor of 4.7u and an output capacitor of 1.5u. However, when I mark these values as 'Locked' and click on redesign from the top menu, it shows me 2x68u as the output capacitors. Which are the right values?

#st1cc40dr #edesignstudio #constant-current

[Patrizia BELLITTO]

Posted on February 18, 2016 at 10:34

Hallo,

thanks for your tip. This LED application is designed in a way that inductor and output capacitor selections are deeply connected each other. Marking one of these components as ''locked'', the design engine isn't able to optimize the calculation.We suggest you to maintain the Cout to the lowest value, 1.5uF, even because it allows a more stable compensation.Meanwhile, we are verifying if it is possible to improve the design so that the optimal values are shown, even in situations like this.Best regards,Patrizia BellittoeDesignSuite developer and support team

[bhrishikesh]

Posted on February 20, 2016 at 06:15

Sure. Let me try with these values.