Part Number:TPS50601-SP
Hi,
I was tweaking my design of the TPS50601 on the EVM and got a result with a short pulse on the SW node. See attached:
Channel 1 = SW node, Channel 2 = Vout, Channel 4 = inductor current
See the short pulse every 3rd on time... I am using a 6.8uH inductor. I tried to design the gain of the compensation loop to be small and used a compensation network of 220nF+1.5kohm // 3.3nF type II. After seeing this I changed to a 4.7uH inductor and get the same result. (actually the image above is from the 4.7uH).
1. Reading https://e2e.ti.com/support/applications/hirel/f/935/t/508983 I realize I did not follow this 1A ripple current rule which is a new one to me. So, my question is could this short pulse behavior be caused by the too small of an error signal / slope compensation? If not what could be the cause of such behavior?
2. Furthermore, can you provide more information on the slope compensation circuit? Is it a scaled down version of the ripple current, during the HS or LS periods, and what is the ideal ripple magnitude to be feed into the current comparator?
Regards,
Michael