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1  Using Arduino / General Electronics / Re: driving an IRF630 from Arduino digital output pin on: August 17, 2011, 09:35:45 am
@ dc42: Thanks for your reply. That's it, with 5V the IRF630 is just ON, so I'm trying to save every mV of gate drive :-)
I am not using PWM or any fast switching. Just switching the LED array ON and OFF with seconds or minutes in between, so switching speed is not an issue here, but the 1kOhm series resistor can even go down to 470Ohms and still have the Arduino channel protected for transient currents due to the parasitic gate-drain capacitance. Of course, using a buffer IC would solve all these issues, but why complicate the circuit and
incur extra costs when this simple gate-drive works well for the current application? @all: Any comments?
2  Using Arduino / General Electronics / Re: driving an IRF630 from Arduino digital output pin on: August 17, 2011, 04:50:43 am
@ joop: Thanks for the reply. As I said, I won't be driving any heavy loads. Only switching an array of LEDs that total to a maximum of 1Amp. No inductive switching etc.
That's why I'm positive that I do not need to include buffers etc. What is your opinion on Option A or option B as gate drive ?
3  Using Arduino / General Electronics / driving an IRF630 from Arduino digital output pin on: August 17, 2011, 04:01:30 am
Dear all,
I need to drive an IRF630 (power N-channel MOSFET) from Arduino. I know this MOSFET requires a VGS of 10V to fully turn on BUT for my application I can work with 5V (I've tested it) and the power loss incurred is very minimal (it is almost fully on at 5V and my currents do not exceed 1Amp). Anyway, my question is this: With reference to the attached figures, would you prefer option A or B to drive the gate from the digital output of the Arduino ? Rser is there to limit any transient current and hence protect the digital port and Rpull is there to tie the gate to ground to avoid damage or the MOSFET from switching on when the gate is open circuited (if ever). Anyway, speed is not an issue here so I can live with Rser. My argument is: In option A the gate voltage would be a little less than 5V (because of the potential divider formed by the two resistors). I though of option B to solve the problem (I know it is a minor one in practice). But I am curious: would option B serve the same purpose better ? Thanks in advance.
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