Usage of TinySwitch for Buck/Buck-Boost operation
Hello,
I would like to desing a small AC/DC converter for my project. It should contain cheap components (tiny smd components on a tiny board area). The maximum current should be 50mA with 6V output voltage.
I know that there are LinkSwitch solutions for the problem but it has to be choosen huge throw hole coil based on the lower switching frequency. TinySwitch would be more appropriate for my solution because a small lower cost smd coil could be used due to its higher switching freq.
I know also that TinySwitch was desiged mainly for Flyback converters.
My question would be if the TinySwitch devices can be used to drive Buck/Buck-boost topologies in AC/DC converters?
Thank you for your help in advance.
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The input voltage of the complete circuit is mains voltage (240V AC). Based on the electricity provider the worst case boundaries of the voltage should be 240Vac +/-10% which are 216Vac and 264Vac.
After rectification the input voltage of the converter will be between 305Vdc and 374Vdc in worst case situation.
The TinySwitch mosfet switch is grounded on the source side to the common return. How do you intend to drive the inductor to achieve a buck/boost solution.?
Both TinySwitch and LinkSwitch product are grounded at the source side and LinkSwitch can be used for Buck/Buck-Boost and also Flyback converter topologies.
See datasheet of LNK33x2: https://www.power.com/sites/default/files/documents/linkswitch-tnz_datasheet.pdf
Because the internal block diagram of TinySwitch and LinkSwitch devices are similar therefore I hoped to use TinySwitch for the same topologies.
Maybe you would be better off with Link TN-2, as it has capability for buck-boost and you don't have to worry about the zero crossing detector. See application note AN-70 - there is a buck-boost option with optocoupler feedback. The advantage of using the optocoupler and Zener for feedback is that a resistive preload is not required for regulation, possibly boosting efficiency, as you are not burning up power in a preload resistor.
Thank you very much.
What input voltage range? DPA-Switch might be a better solution if you expect operation below 30V.