H bridge Rectifier
in [Design]
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From: Jamie on 18 Jul 2010 20:02 john1987 wrote: > Hi, > > I have following questions about the HP4081A > > 1. How does this bootstrap works in this chip and why is it so > important? How does this chip basically function? How is it switching > the transistors? I am using the transistor IRF 520. I am trying to > actuate an inductive load and needs 100volts and 2A current. I am > thinking of monitoring the voltage across the load and will try to > keep it constant using a microcontroller doing pulse width modulation. > But I want to do it using some kind of control algorithm like PID or > something else (Please recommend) and I have not implemented any > control algorithm before. So, will appreciate any advice! > > http://pcbheaven.com/datasheet/irf520.pdf > > 2. I am planning to drive the four N Channel device IRF520 with this > chip and was wondering that how can I calculate the time the chip will > take to charge up the input capacitance of the transistor and how fast > it can switch the transistor? The link of the circuit diagram is as > blow > > http://www.robotpower.com/downloads/HIP4081A-datasheet.pdf > > thanks > John You were told before, but I guess you either don't listen or you think if you ask again, some one will tell you what you want to hear? Looking at the PDF using the MOSFET example with the DIODES and caps in place, you'll see that the cap gets charge via the 12V supply. Then that fet must be turned on, the cap will discharge its store charge between the source and the gate via the BHB and BHO, at this point, a 12 volt ref will be placed from the source to the gate which will thus turn on the Fet.. The on time isn't infinite, so the system needs to pulse to recharge etc.. hence the PWM scheme!.. have a good day.. |