ZHCS026C December 2010 – February 2016 TPS57060-Q1
PRODUCTION DATA.
Figure 38 shows an equivalent model for the TPS57060-Q1 control loop which can be modeled in a circuit simulation program to check frequency response and dynamic load response. The error amplifier is a transconductance amplifier with a gmEA of 97 μA/V. The error amplifier can be modeled using an ideal voltage controlled current source. The resistor Ro and capacitor Co model the open loop gain and frequency response of the amplifier. The 1-mV AC voltage source between the nodes a and b effectively breaks the control loop for the frequency response measurements. Plotting c/a shows the small signal response of the frequency compensation. Plotting a/b shows the small signal response of the overall loop. The dynamic loop response can be checked by replacing RL with a current source with the appropriate load step amplitude and step rate in a time domain analysis. This equivalent model is only valid for continuous conduction mode designs.