Transformerless power supply tester

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john3909
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Transformerless power supply tester

http://www.daycounter.com/Circuits/Transformerless-Power-Supplies/Transf...
The above link is an example of a transformerless power supply. These power supplies tend to fail when the power is applied and the voltage is at a peak value, or at 90 degrees. The capacitor is considered a short circuit and the resistor is used to limit the current surge. However, the resistor generates heat, so there is a trade off between heat dissipated and the max surge current.

To test a transformerless power supply, I want to fire a triac when the phase of the 120VAC input is at 90 degrees. The other pins are only used for debugging. I want to leave the power on for 10 seconds and then turn off the power for 50 seconds to allow the components to cool down. I then want to repeat this cycle for 6 hours, which will give me the equivalent MTBF of 1 year.

I have managed to do this with a SLG46140V using a 4 stage state machine, but I want to add some additional features to detect for failures, which requires more states than I can implement in this device. I have a zero crossing detector connected to Pin3 and a MOC3012 connected to Pin4. I am trying to implement this design in a SLG46537M so that I can benefit from the 8 stage ASM, but this is where I need some help. The asynchronous nature causes all kinds of racing conditions. How can I implement a synchronous state machine with ASM?

Device: 
Device Number: 
SLG46537M
john3909
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One more thing, this solution

One more thing, this solution works when running on the evaluation board connected to my circuit; however, when I remove the carrier board and plug it into my circuit, it does not do anything. On Pin5, I do not see any clock output.

RomanY
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As for PIN5 issue, the output

As for PIN5 issue, the output pulse is very short around 500-700ns, if your system has some capacitance connected to PIN5 output it may be filtered out. You can set PIN5 configuration as Push Pull 2X to get more output current or use a DLY cell instead of a PDLY to generate a longer pulse.

john3909
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Why does this work when using

Why does this work when using the emulation board, but not when using the carrier board alone? All I have connected to this pin is a logic analyzer or a high speed oscilloscope probe, so capacitance on this pin is not an issue. Please program a chip and try this yourself.

RomanY
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Hi john3909, the easiest way

Hi john3909, the easiest way I would recommend is to put DFFs on state enable inputs.