Part Number: TPS65263-Q1
Tool/software: WEBENCH® Design Tools
Hi,
have inherited a design with this chip. It come with values, for compensation networks, that semt well working.
In order to assess this, i tried to simulate in webench the similar TPS65261 part , but probably due to my inexperience with webench could not be able to set the Output voltages needed, one of wich (5V) much higher than default one(0.9V). As i tried, webench kicked me out saying it can not find non better specified component(s).
Anyway with default output voltages webench gave Rc and associated Caps values next to mine. But it appears not to be there a linear proportion, neither inverse, between Rc and Out voltages so can not infere CH1 Rc (and caps) value from webench suggestions.
Then I also wanted to try out the formulas given in 263 datasheet, using 1Mhz fck, 100khz Fc, and RL = V/expected max current; this for each branch.
Found Rc values are much higher than previous ones, hundreds kohms vs kohms. I tried these value sets in my HW and the control loops got all very unstable.
How can i calculate proper values then? Our designs are all digital, and experience rare steps in absorption and durable constant absorption intervals. By other hand, we need sourcing currents next to higher chip limits. So i guess i could advantage from slowing down the regulation response in order to limit the pwm jitter and avoid overcurrent thresholds tripping.
Thanks for any suggestion
Francesco