Peer-to-peer, engineer-to-engineer questions and answers from the EDABoard.com engineering community around power electronics. Click the “Read more” link and follow the entire conversation and maybe add your two cents by logging in to EDAboard.com
Practical circuit problems – I tried to make an experiment with a “push-pull inverter” and it worked in simulation (software LTspice) but when I tried a practical example it failed. Why? Read more
MOSFET as switch to cut power to a BMS in a 4S Li-ion? – I am building a power-pack from old Nissan LEAF modules. To make sure not to destroy any of the cells in the 4S configuration I am using a “1-8S Lipo Li-ion Fe Battery Voltage 2IN1 Indicator Tester Low Voltage Buzzer Alarm For RC Car Boat LED 3.7-30V Dual Speaker” since they are very cheap, and very light. (I am using an external balancing charger). My problem is that I cannot turn this device off unless 4 out of 5 pins are disconnected. Even if I cut the ground the device will still be active. I want to just push a switch and turn the whole thing off. Read more
Flyback charger circuit – I am designing 65v/3amps flyback charger circuit with the reference circuit from PI. I connected the input supply through a resistor (33ohms 10watt) in phase for protecting the circuit. When I switch on the supply, the input current is going 3.5 amps .and resistor gets very hot (burn). Read more
150W offline LED driver cannot possibly be 95% efficient? -A certain major streetlighting company is purporting to have Offline, 220VAC, 150W, dimmable LED streetlights which have efficiency of 95%. This streetlight is dimmable from 5W to 150W.Do you agree that this is not possible with anything other than ridiculously expensive circuitry? Read more
Mains in UK can go up to 292VAC for periods of several minutes – Read more
Problem in firing the TRIAC – I just want my transformer to turn on through the Triac at zero-level crossing to reduce the inrush current. My problem is that I’m detecting the zero-crossing using an op-amp and X-OR gate. Read more
Power supply output voltage problem – I have used PI expert to design a dual output voltage power supply 5V and 12V. The 5V is the one being regulated and it needs to be fairly stable as it supplies sensitive circuits. The 12 V supply is only feeding a relay, so it is allowed to vary. The output is 5.6V, where I need to get 5V. For flyback loop, I have used TL431 and optocoupler PC817. I have also used zener diode. Read more
Calculating Inrush current limiter -I require a inrush current limiter design for an inverter with 1000 watt [230volt rms ,50HZ sinewave. Are my calculations correct? Read more
Two-switch converter bootstrap -I’ve just build a two-switch flyback converter (Vin=48VDC, Vout=12VDC, Pout=50W) but the boostrap circuit for the high-side driver doesn’t work quite well. During the MOSFET switches OFF period, the low-side freewheeling diode is only forward biased for a (too) small period of time (I suppose) hence the bootstrap capacitor doesn’t get enough charge. Read more
Flyback power supply – I designed flyback power supply 65v/3amps using Topswitch262EN . I got the output 65v stable. When I put the load 1amp it is ok but when I increase the load 2amps the output is going off. I am not understanding the waveform. Read more
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