cupoftea
Advanced Member level 5
Hi,
Doing Synch Buck for 27Vin, 13V out, 15A out and 450kHz.
LTpowerCAD is showing the gain Bode plot curving back up to the 0dB line at higher
frequency than the crossover. - Which means instability.
As such, wish to make out own Bode plots.
Can get the Power stage transfer function for a current mode CCM Buck.
Can get the Transfer function for the type 2 transconductance error amplifier.
However, can you confirm that the controller gain means that we will have to multiply in
the factor of 1.4V/0.075V for the attenuation regarding the peak current threshold (75mV)
and the maximum control voltage, which appears to be 1.4V?
Graph on top left of datasheet page 7 appears to show the controller gain, by way of V(ITH) vs Current sense voltage
LTC3891 datasheet
Doing Synch Buck for 27Vin, 13V out, 15A out and 450kHz.
LTpowerCAD is showing the gain Bode plot curving back up to the 0dB line at higher
frequency than the crossover. - Which means instability.
As such, wish to make out own Bode plots.
Can get the Power stage transfer function for a current mode CCM Buck.
Can get the Transfer function for the type 2 transconductance error amplifier.
However, can you confirm that the controller gain means that we will have to multiply in
the factor of 1.4V/0.075V for the attenuation regarding the peak current threshold (75mV)
and the maximum control voltage, which appears to be 1.4V?
Graph on top left of datasheet page 7 appears to show the controller gain, by way of V(ITH) vs Current sense voltage
LTC3891 datasheet
Last edited: