I was working tps92210 IC for flyback non dimmable driver,i was facing problem in no load protection, please let know on what pins of IC i need to work on
This thread has been locked.
If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.
I am assuming you are using an opto-isolator for current feedback and are looking to protect in case of open LED. If this is the case then an additional circuit added to the secondary side (LED side) that uses the output voltage to feedback when it gets too high can be designed.
This can also be done on the primary side via the bias supply voltage but the transformer leakage inductance needs to be taken into account (this can be solved with a small resistive load across the LEDs)
Example: LED stack is 30 volts. A voltage monitoring circuit would take over at around 35 volts to drive current through the opto-isolator so the secondary side starts regulating voltage since the current regulation is no longer working. This can be done through the same opto-isolator (as an or-ing function) or a separate opto-isolator.
Depending on how the TPS92210 is set-up there may still need to be a minimal resistive load or zener type clamp on the secondary side to prevent the output from creeping up.
Output Power for 12,15,18W ,
Input voltage 180-265V,
Basically we want to work on tps92210 only for that we have seen application note pmp6003, but can you please help me out in starting up the project, triac dimming by determining dimming angle
PMP6003 is using D6 (and associated circuitry) to decode the dimmer angle. This can be done many ways but this is a good way to prevent needing another opto-coupler. It is decoding whether or not input voltage is present by watching the forward voltage through the flyback transformer (it's a negative voltage). Basically it reduces current (via the feedback loop) as the dimmer is turned down. There is also a loading circuit, U3 connect to Q2 that aides when dimming to keep the triac from misfiring and allowing for deeper dimming.
On the input, C1 and R5 are important to keep the input current from ringing negative when the triac fires. If it rings negative for a long enough time the triac will shut off. This will result in flickering. C1 and R5 are a damper for C29 and also for L2 and C9. C1 is large enough and R5 allows for enough current to latch the triac as well during the triac firing time. For even better interface to the triac dimmer, F1 can be changed to a UL rated fusible resistor anywhere from 22-68 ohms depending on power level and efficiency loss desired.