jc_lim3 Posted March 26, 2006 Report Share Posted March 26, 2006 hi peeps! I need you help. Can you help me confirm if my drive circuit is usable? here's the link to my schematic diagram. Quote Link to comment Share on other sites More sharing options...
Tony_Stoynov Posted March 26, 2006 Report Share Posted March 26, 2006 Hi,what is the supply of your trigger, and way if you have a uC put this shmid trigger. If the output of your triger not going to 12 V you cn have a problem, actually you wil have a problem, becose your PNP will be open. To control the transistor is used the current Base-Emiter. In your case, if you have 5 V on the base, and 12 V on the emiter, you will have a emiter to base current that will open the transistor. This curent is limited from trigger high level current and your base rezistor. In your case the output will be always high, and the mosfet wil be always ON.You can use the NPN tranzistor. Quote Link to comment Share on other sites More sharing options...
Staigen Posted March 26, 2006 Report Share Posted March 26, 2006 Hi jc_lim3You haven't suplied us with enough information! ???The smitt-trigger, what is that, is it feeded from an input of a microcontroller? ???What is the output from the smitt-trigger? Open collector?Also, the gate cap of the mosfet makes it switch slow.//Staigen Quote Link to comment Share on other sites More sharing options...
jc_lim3 Posted March 27, 2006 Author Report Share Posted March 27, 2006 Thanks for your reply! I have revised my schematic. Here's the link Are both schematics usable? P.S. I was making this alternative drive circuit because previously I just hooked up the gate to the uC output pin and the MOSFET couldn't drive my load though the datasheet of the MOSFET (MTP10N10EL from ON Semiconductor) said the gate voltage is logic level compatible. Quote Link to comment Share on other sites More sharing options...
Staigen Posted March 27, 2006 Report Share Posted March 27, 2006 Hi again jc_lim3If you switch out your 74HC365 to a SN74LS07 it will work, at the same timeremove the PNP transistor and the 2.2K and 10K resistors. connect the 4.7Kresistor between 12V and the output of SN74LS07, also connect this to themosfet gate. Maybee you should have a pair of complemantary drivingtransistors between the SN74LS07 and the mosfet's gate to increase the switching speed.//Staigen Quote Link to comment Share on other sites More sharing options...
steven Posted April 20, 2006 Report Share Posted April 20, 2006 :)driver circuit for an n channel mosfet, well look at the high voltage flyback transformer driver circuits in the high voltage stuff section in electronics lab here they are n channel mosfet drivers, even for the high voltage p[hoto flash capacitor chargers one uses the n channel mosfet driver to Quote Link to comment Share on other sites More sharing options...
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