4 5 decimal

&[DATE] &[TIME] - &[FILENAME]

This sheet demonstrats problems with inequalities and units where sometimes (not all the time) it says units don't match, even though they clearly do, perhaps this is when the exponent is different?

mΩ Ω 1000 / :

Givens:

V.out 3.3 V * :

V.in 12 V * :

V.in 10 V * :

I.omax 3 A * :

R.2 11.8 kΩ * :

I.indr I.omax 2 / :

f.SW 600 kHz * :

R.r 15 kΩ * :

R.L 11.8 kΩ * :

R.U 40.2 kΩ * :

L 1.8 μH * :

R.ind 18 mΩ * :

C.o 282 μF * :

R.TON 100 kΩ * :

I.indr V.in V.out - (V.out * L f.SW * V.in * / :

I.indr 2.0472 A *

T.on 19 pF * R.TON * 23 / V.out * (100 mV * + V.in / (* 50 ns * + :

We must ensure

C.r C.c > 12 π * f.SW * R.L R.U * R.L R.U + / (* / >

L C.o * R.r C.r * / T.on 2 / >

AND

V.indr I.indr R.ind * :

V.indr mV 36.85

V.cor I.indr 8 C.o * f.SW * / :

V.cor mV 1.5124

k 12 mV * V.indr / :

k 0.3256

R.r C.r * L k R.ind * / ≡

RRCR L k R.ind * / :

RRCR 0.0003 s *

Note: Units are the same

L C.o * RRCR / ns * T.on 2 / ns * > 1

0 IS BAD, 1 IS GOOD

L C.o * RRCR / 1.653 106 -^* s *

T.on 2 / 2.435 107 -^* s *

L C.o * RRCR / T.on 2 / > 1

<-- BUG? 'units don't match'

L C.o * RRCR / ns 1652.9715

T.on 2 / ns 243.5

C.r RRCR R.r / :

C.r nF 20.4722

Select Cc to be small compared to Cr to improve transient response

C.r 2.0472 108 -^* F *

C.c 470 pF * :

C.r 12 π * f.SW R.L R.U * R.L R.U + / (* (* / > #

<-- BUG? 'units don't match'

12 π * f.SW R.L R.U * R.L R.U + / (* (* / nF 0.0291

C.c 12 π * f.SW R.L R.U * R.L R.U + / (* (* / > #

<-- BUG? 'units don't match'