Proteus- Timestep Too Small error Message

[Ogbachi]

All,

I am unable to run my simulation using Proteus software. It pops out ''timestep too small error message'' Can anyone help on how to proceed resolve this?

Please find the attached file below. Could anything be wrong with the design? The driver works well when run separately. Please help.

Thanks,
Ibrahim.

 

[BradtheRad]

* Did you try various timesteps? Higher? Lower?

* There may be some transient event which is only incidental to circuit operation, yet which takes up the simulator's time as it tries to resolve it. If you try a faster timestep, the simulator may ignore it more easily.

* Do you have diodes and coils next to each other? At low current flow they might alternately conduct, in oscillation. It can help to put a resistor across the ends of a coil or diode, or from one end to a supply rail.

* A simulator does not always like two capacitors in series, or a capacitor across a power supply. Try installing a resistor inline with a capacitor.

 

[dick_freebird]

Add to this list, logic circuits built with ideal transistors
and not reasonable parasitic capacitances. Insane edge
rates result. Make sure whatever you're driving has sane
series resistances and shunt capacitances.

 

[Ogbachi]

Add to this list, logic circuits built with ideal transistors
and not reasonable parasitic capacitances. Insane edge
rates result. Make sure whatever you're driving has sane
series resistances and shunt capacitances.

BradtheRad/Dick,

The timestep too small error message has been resolved by installing 1k Ohms between gate and source. The voltages and current measured are as calculated but wave form not looking good- very high oscillation. From the Oscilloscope, the inductor current is oscillating. Find the attached snapshot below.

Please, can you assist me to look at the design for any design error?

I ejectected Positive PULSE GENERATOR AT Q1&Q3 and negative at Q2&Q4

Thanks,
Ibrahim.

 

[BradtheRad]

Sorry, your files are in a proprietary format. I find two files but I do not have any program that can read them. (Nor could I read your post #1 attachments.)

Can you take screenshots of your images, and attach them as graphics files?

The voltages and current measured are as calculated but wave form not looking good- very high oscillation. From the Oscilloscope, the inductor current is oscillating.

* This suggests ringing in your coil. Is there a capacitor close to it? Creating resonant action?

* A coil generates its own current for a brief time after you shut off its current flow. This can result in high voltage spikes, particularly if it suddenly sees high impedance.

 

[Ogbachi]

Sorry, your files are in a proprietary format. I find two files but I do not have any program that can read them. (Nor could I read your post #1 attachments.)

Can you take screenshots of your images, and attach them as graphics files?



* This suggests ringing in your coil. Is there a capacitor close to it? Creating resonant action?

* A coil generates its own current for a brief time after you shut off its current flow. This can result in high voltage spikes, particularly if it suddenly sees high impedance.

BradtheRad,

Please find attached pdf copy below.

How can ringing in a coil be eliminated? I do not have capacitor close to the coil.

Thanks.

 

[BradtheRad]

R11 is unclear. It looks as though it is 1 ohm across a power supply.

Q1 gate does not appear to be connected to anything.

Q1 and Q3 may need to have gate voltage increased, in order to turn them on.

 

[Ogbachi]

R11 is unclear. It looks as though it is 1 ohm across a power supply.

Q1 gate does not appear to be connected to anything.

Q1 and Q3 may need to have gate voltage increased, in order to turn them on.

BradtheRad,

Many thanks on your response. R11 is 1.0 Ohms, is anything wrong with selection?

You are right, Q1 gate was not connected but when it was connected it did not change the previous result.

Can you assist me to look at the coupled inductor connection if that is the proper connection?

Thanks,
Ibrahim.

 

[dick_freebird]

Every real inductor has series resistance; add some as
a component if your inductor primitive has no Rs term.
Similarly every real capacitor has Rs. When you have
a square voltage step, somebody had best prevent an
infinite current spike or a ring-up that is so fast that
you step right past a bistable point instead of through
it, orderly. This is how binary-search solvers get lost
and can't recover, because backward != forward.