Other Parts Discussed in Thread: TINA-TI, , TPS54821
Tool/software: TINA-TI or Spice Models
Hi,
I am migrating the power converter design from TPS54821 to TPS54824.
Due to changed characteristics between the 2 devices, I am trying to adjust the compensation RC (type II compensation).
I can easily achieve a frequency response with monotonously decreasing amplitude and phase curve for TPS54821, for my range of supply and load condition. The response curve does not deviate much with change of load. Although the actual performance was not measured, but the actual power converter is working great.
However, for TPS54824, the problem is that I can hardly find a compensation RC value which can satisfy at least both heavy and light load condition (or the supply is changed). The response curve seems to indicate some control performance problem once the supply or load is changed.
The similar result can be found using the original components in TPS54824 TINA-TI Average Reference Design (Rev. A) 09 Feb 2017, but with the LOAD resistor changed to different resistance value to simulate load condition change. At light load, there would be a large "bath top" phase response before crossover frequency, with the center of the "bath top" quite close to 0deg, which seems to indicate control performance problem.
Thank you a lot.
