Hello,
I am in need of some clarification on slope compensation. After reading some articles on Rohm, and the often suggested paper from Rob Sheehan on how to apply current mode control theory, I am just utterly confused.
For example:
1. "The Reason Why Compensation Ramp Slope must be at least 1/2 down slope" by Rohm
2. Robert Sheehan's paper " Understanding and Applying Current-Mode Control Theory "
https://techweb.rohm.com/knowledge/dentatsu/s-dentatsu/s-dentatsu03/3790
https://www.ti.com/lit/an/snva555/snva555.pdf?ts=1674662544454&ref_url=https%3A%2F%2Fwww.google.com%2F
I see three different suggestions on the slope of the comp ramp, and I am sure I have read so much that I am lost.
1. Rohm paper's math is 1/2 the inductor down slope (presume independent of topology - buck, boost, buck-boost)
2. Robert's paper I swear says 2 different things between page 5 and 6: a) " By adding a compensating ramp equal to the down-slope of the inductor current ", and b) " the optimal slope of the ramp presented to the modulating comparator input is equal to the sum of the absolute values of the inductor upslope and down-slope
Is the correct comp ramp 1) 1/2 down slope, 2) down slope, 3) sum of the up and down slopes?
What in the world am I missing? Even if we presume a peak current mode control buck.
I am in need of some clarification on slope compensation. After reading some articles on Rohm, and the often suggested paper from Rob Sheehan on how to apply current mode control theory, I am just utterly confused.
For example:
1. "The Reason Why Compensation Ramp Slope must be at least 1/2 down slope" by Rohm
2. Robert Sheehan's paper " Understanding and Applying Current-Mode Control Theory "
https://techweb.rohm.com/knowledge/dentatsu/s-dentatsu/s-dentatsu03/3790
https://www.ti.com/lit/an/snva555/snva555.pdf?ts=1674662544454&ref_url=https%3A%2F%2Fwww.google.com%2F
I see three different suggestions on the slope of the comp ramp, and I am sure I have read so much that I am lost.
1. Rohm paper's math is 1/2 the inductor down slope (presume independent of topology - buck, boost, buck-boost)
2. Robert's paper I swear says 2 different things between page 5 and 6: a) " By adding a compensating ramp equal to the down-slope of the inductor current ", and b) " the optimal slope of the ramp presented to the modulating comparator input is equal to the sum of the absolute values of the inductor upslope and down-slope
Is the correct comp ramp 1) 1/2 down slope, 2) down slope, 3) sum of the up and down slopes?
What in the world am I missing? Even if we presume a peak current mode control buck.