Can 555 based PWM run 600 watt motor ? - Page 1
Forum section: electronics / beginners

author: Shobos
author_rank: Contributor
timestamp: April 15, 2014, 03:37:47 pm
content: Hello, i have question about well known 555 timer pwm, my question is if i use 110amp 60 volt mosfet can i use it to run 12 v 50 amp 600 watt motor ? Seems like a dumb question but it sounds too good to be true.

author: Rick Law
author_rank: Super Contributor
timestamp: April 15, 2014, 03:49:08 pm
content: Quote from: Shobos on April 15, 2014, 03:37:47 pmEDIT - I removed my reply. Posted too soon before I finish. Something else just came up, I was trying to hit exit but hit post instead by mistake.

author: Phaedrus
author_rank: Frequent Contributor
timestamp: April 15, 2014, 03:54:37 pm
content: With isolation and a driver stage I don't see why not; though I would personally use an IC designed specifically for high-power applications which might have built-in protections.

author: Shobos
author_rank: Contributor
timestamp: April 15, 2014, 03:59:01 pm
content: What You mean by 'With isolation and a driver stage' Im really a newbie here.

author: Richard Crowley
author_rank: Super Contributor
timestamp: April 15, 2014, 04:26:53 pm
content: Isolation to keep those large current switching anomalies (spikes, etc.) away from the control circuit so that it can work in without interference. Typically accomplished by good power supply decoupling and perhaps even opto-isolation of the gate signal(?)Driver Stage because the 555 may not be able to DIRECTLY drive such a large power semiconductor, at least with enough margin to ensure you aren't living live on the edge. This may be as simple as another transistor between the 555 and the switching device.

author: Phaedrus
author_rank: Frequent Contributor
timestamp: April 15, 2014, 04:30:55 pm
content: In other words, instead of connecting the gate of your power mosfet directly to your 555 (which could fail in a half dozen interesting ways), I would run your 555's output signal through an optocoupler, then connect that to the gate of a general purpose NPN transistor; and use that transistor to drive the gate of your power mosfet.

author: Shobos
author_rank: Contributor
timestamp: April 15, 2014, 04:32:16 pm
content: Thanks You very much people !

author: David Hess
author_rank: Super Contributor
timestamp: April 15, 2014, 06:35:47 pm
content: Or isolate the input to the control circuit which itself is connected directly to the power MOSFET.

author: jlmoon
author_rank: Unknown
timestamp: April 15, 2014, 07:43:13 pm
content: Have you considered a LM3824 or LM3524 pwm circuits driving optocouplers with high power mosfets and current sensing feedback to control faults, overvoltage / current situations. National semiconductor has some pretty nice app notes on these parts."Hello, i have question about well known 555 timer pwm, my question is if i use 110amp 60 volt mosfet can i use it to run 12 v 50 amp 600 watt motor ? Seems like a dumb question but it sounds too good to be true. "You mention running low voltage with lots of current.. just keep in mind drv(i) / drv(t) will derive what you can do with your power dissipation. ie: more current then less time.. vice versa ..JLM