Tony_Stoynov
- Dec 20, 2005
- 197
- Joined
- Dec 20, 2005
- Messages
- 197
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.
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.
Hi jc_lim3
You 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
You 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
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.
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.
Hi again jc_lim3
If you switch out your 74HC365 to a SN74LS07 it will work, at the same time
remove the PNP transistor and the 2.2K and 10K resistors. connect the 4.7K
resistor between 12V and the output of SN74LS07, also connect this to the
mosfet gate. Maybee you should have a pair of complemantary driving
transistors between the SN74LS07 and the mosfet's gate to increase the switching speed.
//Staigen
If you switch out your 74HC365 to a SN74LS07 it will work, at the same time
remove the PNP transistor and the 2.2K and 10K resistors. connect the 4.7K
resistor between 12V and the output of SN74LS07, also connect this to the
mosfet gate. Maybee you should have a pair of complemantary driving
transistors between the SN74LS07 and the mosfet's gate to increase the switching speed.
//Staigen
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 toSimilar threads
