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

Dell power supply – I got this PSU from one of my colleagues and did a quick inspection for the faults in this PSU. I recorded a video on YouTube and looking for opinions and ideas about this unit before I do any desoldering. Read more

CMC UCC3808A2 current sense gain implications – I would like to know the implications of the Current Sense Gain value (2.2 V/V) of the UCC3808A2 in the control loop. Particularly, let’s consider the following circuit. Read more

Arcing between drain/source/gate pads – What are the chances of getting arcing between in-line TO220 pads on a 60W Offline Flyback SMPS FET. (FR4 PCB coated with solder resist)? Our contractor has designed a 60W offline (240VAC) Flyback LED driver (PFC’d) for us. It is for outdoor use. The footprint for the TO220 primary FET is just three PTH pads in a line, ie, no bending out of the middle leg of the TO220 to facilitate greater clearance between the Drain pad and the other. Read more

Buck converter for 96V to 60V – I need to design a buck converter where
vOUT=60V
vIN=96V
ILOAD is what is required to drive a comparator IC whose inputs are a reference voltage 96V and buck converter output (both suitably reduced). How do I choose the components for the buck converter circuit? Read more

Question on speed control vs torque control – I’m controlling a permanent magnet DC motor with a PWM for a treadmill. I’m using a reflective sensor with 6 pulses per rev to get a speed feedback. So I’m actually doing “speed control” directly, but not “torque control”. So I have two specific questions:
1- Do I need direct torque control for this application by measuring the current? Or a combination of speed and torque control where a cascade PI is needed?
2- Do I strictly need to know the DC motor parameters (R, L, K, J, B) in order to do speed control? Read more

Fuse amperage determination circuit – I need to build a 12V circuit which can determine the amperage of various automotive fuses. In other words, a circuit which can show at what amperes the fuse blows out. Read more

High-efficiency buck topologies – I am trying to design an isolated buck topology converter. The input is 100-120 volts and output is 60+-12 V with 600W power. I have seen many application notes for 600W converter using PSFB (400V to 12 V) having efficiency over 95%. I want to know whether using PSFB with or without synchronous rectification is suitable for my design with efficiency over 95%. Read more

60Hz regulator for 110V – I am in need of a circuit that will take 110V/60hz from standard wall AC and regulate the 60z, keep it at a constant 60Hz. Read more

AC motor brake system – I have this single-phase AC motor 110 V/750 Watt/10 Amps. Installed in a meat grinder. Safety regulations required motor stop within  2 seconds or less once you press the emergency button or open the lid. I tried brake circuit using relay reversing but it is not really functioning.  Read more

DC-DC buck-boost nonisolated converter topologies – What are the practical bidirectional topologies for non-isolated buck-boost converters for efficiencies above 95% at 1.5 MHz switching frequency and output power above 65W? Read more