Re: The Power Supply Modding Guide (or TL494 -> Anything)

Hmm...wouldn't it be too "late" if the overpower protection is used for short circuit protection? It has a capacitor after the diode that samples the peak voltage from the base drive transformer, which will delay for quite some time before it shuts down the supply I don't want to replace the transistors if the cheap power supply blows!


In fact I already did so. But I thought there are some other ways that won't affect the bode plot of the stage......

Re: The Power Supply Modding Guide (or TL494 -> Anything)

Yes, you are right, it is the pin 4 that controls the overpower protection. However, it serves two purposes in the SMPS: when the voltage crosses 1.25V it shuts down the supply(overpower protection), when the voltage is lower than about 0.6V it disables the undervoltage protection. I found some voltage divider (linked to the base drive transformer) and also a capacitor near that pin, presumably to provide the delay during startup before enabling the UVP.

However, what I feel is that, the error amp responds...

Re: The Power Supply Modding Guide (or TL494 -> Anything)

I am also on the way of modding an 450W ATX Power supply into a +-40V dual power supply suitable for audio power amplifiers. The "normal" feedback is OK, and it is supplying the required voltage into a dummy load. However, the last thing I have yet to perform successfully, is the feedback loop compensation. I have tried the type III compensation but it is not working very well; the over-power protection circuit trips very often when the audio amplifier (which is powered by the power supply) is producing some...

Re: New Members - please post your introductions here

Hi, I am currently studying in electronic engineering and also an amateur radio operator. I love to experiment and design circuit and PCBs myself, which is my way of self-guided learning. The reason I am here is to find out some interesting people who designs interesting power supplies, for powering up any circuit that it may be.