
Systemdesigner LLC电路 IC行为级建模 离线式flyback变换器 768Hz带通道滤波器 
LLC Resonant converter Input:380V Output:24V Power:120W Turn ratio:7.5:1 Resonance parameter:Lp=998uF, Lr=234uF, Cr=15nF
The voltage and current waveforms of each node of the circuit are observed, the efficiency and loss are calculated,
the BodePlots are obtained through AC analysis.
Results:
LTC3406B is a synchronous stepdown voltage regulator oscillation frequency:1.5MHz peak efficiency:96%
SIMPLIS supports the behavior level modeling of IC.
The user can builds its behavior model according to the description of the internal function of the chip in datasheet.
The IC model can be divided into submodules to verify the functions of each submodule. . Then the whole model is built to verify the design of IC model.
The following figure shows the internal circuit diagram of the LT3406B built in the SIMPLIS.
This example divides the LTC3406B into six functional submodules:
Oscillator and ramp generator, error amplifier, skew compensation circuit, enable circuit, logic unit and drive circuit.
The following figure shows a typical LTC3406B application circuit,
Input voltage:5V
Output voltage:1.505V
Output current:1.5A
switching frequency：955KHz
Currentmode Offline flyback converter Control chip：UC3844 Input voltage：160V Output voltage：5V switching frequency：100KHz Turn ratio:10:1
Analytical model:
Transient 8ms
Simulation purpose:
Verify that the circuit works properly, the output voltage is stable, the power supply for control chip is normal, and the feedback voltage is properly designed.
Output voltage waveform
Power supply voltage waveform
Feedback voltage waveform
Results:
Output voltage:4.8V
Ripple voltage:163mV
Power supply voltage:16.3V
band pass filter Input sine source: 768Hz operational amplifier:tl062 Resistance precision:1% Capacitance precision:10%
Analytical model:
AC analysis: Sweep range:650Hz~950Hz Monte Carlo analysis: 100 steps
Simulation purpose:
The frequency domain waveform of the circuit is obtained by AC analysis, and the filtering effect is observed.
The column diagram distribution of the output voltage is obtained by Monte Carlo simulation, which provides the data basis for the tolerance design and statistical distribution of the circuit elements.
Results:
The average output voltage frequency is 764.788Hz,
the standard deviation is 16.5089,
the minimum value is 714.888, the maximum value is 827.984.
Reasonable tolerance design is carried out according to the frequency domain waveform and column diagram distribution of the output voltage.