Powerful Products for Communications Power Supply Development Electrical and Mechanical Simulation...

Powerful Products for Communications

Power Supply Development

Electrical and Mechanical Simulation

Missing Links

Lorenzo Cividino


Our Objectives for Electrical Simulation

• Design Verification Testing– of production schematic– results in 48 hours (schematic complete to results

available)

• Requires 300 - 500 simulation tests– total CPU time for tests should be under 6 hours


Implications for Electrical Simulation

• Must be able to manage circuit and simulation complexity– Must be able to extract relevant portions of production

schematic for each test– Must be able to optimally model critical components

for accuracy and CPU time

• These application specific simulation requirements require a new simulation architecture


New Circuit simulation architecture

Schematic Capture•graphical representation of interconnect•display of highlighted components•back annotation of selected attributes (value, part number, etc.)

Simulation Manager•Strategy formulation•prepares simulation input, including sources and loads•manages data files used for back annotation and highlighting

Simulation Engine

•Does number crunching


New Circuit simulation architecture

Schematic Capture•graphical representation of interconnect•display of highlighted components•back annotation of selected attributes (value, part number, etc.)

Application SpecificSimulation Manager•Strategy formulation•prepares simulation input, including sources and loads•manages data files used for back annotation and highlighting

Simulation Engine

•Does number crunching

Need standard interfaces


Thermal Simulation and Mechanical Design

• A similar situation exists in this world as in the electrical world:

– Just as it is difficult to drive electrical simulation with a production schematic, it is very difficult to drive thermal simulation with production MCad drawings

– The level of physical detail in MCad files is too great for timely simulation of airflow and heat transfer


Thermal Simulation and Mechanical Design

• Time is the critical driver in the development process– Must be able to create thermal simulation model of new power supply in

2 days

• There is a growing need to do thermal simulation of magnetic structures as power densities increase– this suggests another interaction between software systems -- thermal

simulation and magnetics design


Power Supply Simulation

• Challenges background– Complex electrical, mechanical, thermal system– Circuits often are dissected into functional circuits

• varying time frames– switching transition (10’s of nS)– multiple switching cycles( 10’s of uS)– control loop time frame (100’s of switching cycles)– supervisory/monitoring circuit time frame (mS to seconds)

• Varying complexity– Power stage stress analysis– Control loop stability analysis– auxiliary circuit interaction(current share/protection



• Issues with current simulation software

– Convergence problems

– Data files too large / simulation time too long

– Most complex component models too complex for most test

– Power Supply circuit too complex to simulate as a complete circuit. No tools to segregate / simplify design schematic for simulation.



• Solution to issues

– Variable component model complexity suited to test being performed

– Variable circuit complexity linked to test being simulated

• What’s needed to implement solutions

– Interface between design schematic and simulation engine – Standard Simulation Interface

Powerful Products for Communications Power Supply Development Electrical and Mechanical Simulation...

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