RCOMP, CCOMP and
CHF configure the error amplifier gain and phase characteristics to
produce a stable voltage loop. For a quick start, follow the following four steps:
- Select crossover frequency,
fC. Select the cross over frequency (fC) at one fifth
of the RHPZ frequency or one tenth of the switching frequency whichever is
lower. Choose RHPZ with minimum input voltage and maximum output voltage.
Equation 81.
Equation 82.
Crossover frequency fc=1.6kHz is
selected.
- Determine required
RCOMP
Knowing fc, RCOMP is calculated
as follows:
Equation 83.
A standard value of 20kΩ
is selected for RCOMP
- Determine
CCOMP
Place ωZ_EA at the load pole frequency
ωP_LF to cancel load pole. Knowing RCOMP,
CCOMP is calculated as follows:
Equation 84.
A standard value of 65nF is selected for
CCOMP
- Determine CHF.
Place ωHF at ωRHPZ or ωZ_ESR zero
whichever is lower. Knowing RCOMP, RHPZ and ESR zero,
CHF is calculated as follows:
Equation 85.
A standard value of 1nF is selected for
CHF.