7 years ago
I am trying to simulate a buck and a boost converter using Christophe
Basso's generic PWM models (in LTSpice) for voltage mode controlled and
current mode controlled switched mode power supplies. These models have
an integrated PWM generator and power switch.
These models can be found here:
(alternative, go through:
The Current Mode Controller model has the following pinout:
nA nC nP nVCtrl nD : Active Pin, Common Pin, Passive Pin, Control
Voltage Input, Duty Cycle Output;
with the following parameters: Params: Lsw=100uH Fsw=100kHz
DCMax=0.95 DCMin=0.05 RISense=1 Slope=100m
For the current mode controller, the slope parameter (used as external
slope compensation) and RIsense are critical to using the model
correctly. I set the Slope to half the value of the downward slope of
the inductor current.
However, I do not understand what value should be used for RISense.
I would like to know if anybody has used the current mode modulator
(PWM-CM) and can help me with this.
(The examples directory in the download has a current mode controlled
boost converter with a RISense value of -40m. The negative value
confuses me all the more.)