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mag
Joined: 05 May 2004
Posts: 41
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 19 Jul 2004 1:32 How to build a program slew control circuit? |
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| how to build a program slew control circuit,My systerm need rise and fall slew control,how can i use amp to build it?
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bear7679
Joined: 18 May 2004
Posts: 135
Helped: 21
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| 19 Jul 2004 6:37 Re: How to build a program slew control circuit? |
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| The OP's slew rate affected by two reasons, the unit gain bandwidth of the OP the driving current of the output stage. You can make the output driving current large enough and control the OP's unit gain bandwidth to control the slew rate.
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asd913
Joined: 24 Jun 2004
Posts: 10
Location: Canada
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| 19 Jul 2004 6:55 How to build a program slew control circuit? |
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I've never had to build one of these but my idea would be to use a programmable filter.
As the slew rate is a property of the driver, it's can't directly be changed. However, we should consider that a squarewave is simply made up of a number of harmonics. These separate signals can progressively sum to form a squarer signal; each harmonic effectively decreasing ripple and rise. time.
Therefore, all you need to do is build a low pass filter at a significantly higher filter frequency than the actual signal.
Each additional harmonic has a diminishing effect of the rise/fall time. If you spend the time to determine what the actual effects are for each harmonic, you can build a hash table to program the filter frequency.
asd913
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mag
Joined: 05 May 2004
Posts: 41
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| 20 Jul 2004 0:50 Re: How to build a program slew control circuit? |
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Sorry,I don't to control amp slew rate.
I want to build a slew rate circuit with amp to control mosfet,this mosfet use as a electronic load.
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