Internal Structure of motor adapter

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engineergc

New Member

• Nov 17, 2016

• #1

Hi,

I will use MC33039 motor adapter in a design. MC33039 doesn't have a spice model. Therefore I will design internal structure of MC33039 myself. I am working the understand internal structure of MC33039. I think delay and xor gates are used to provide edge detection. Also, schmitt trigger is used for noise immunity. But I can not understand purpose of or gate and monostable. Could you explain me?

 

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alec_t

Well-Known Member

Most Helpful Member

• Nov 18, 2016

• #2

Page 3 of the datasheet explains the operation.

 

E

engineergc

New Member

• Nov 18, 2016

• #3

I read datasheet many times. I built below circuit in LTSpice. At the output of or gate I take 5V, so set is 5V and reset is 0V. Since reset is 5V and reset is 0V, Q output of SR Latch is 5V. Purpose of this entegre provide speed control of motor. What are the function of or gate, nor gate and sr latch? Regards,

 

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• sim.PNG

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alec_t

Well-Known Member

Most Helpful Member

• Nov 18, 2016

• #4

The OR gate enables any one of the three position sensors to set the latch. The NOR gate enables the lower opamp to reset the latch when (a) the OR gate output has gone low and (b) the capacitor voltage has dropped below 0.3V.

 

E

engineergc

New Member

• Nov 18, 2016

• #5

I understood purpose of latch. But in my simulation results are not correct. When negative and positive edges detected, I take below simulation results. When hall sensors connected to or gate, I take only 5V. Could you examine my design?

 

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• mc33039.asc

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alec_t

Well-Known Member

Most Helpful Member

• Nov 18, 2016

• #6

Can't run your sim as I don't have all the models. Here's my version (A1 etc have default values for 1V logic).

 

alec_t

Well-Known Member

Most Helpful Member

• Nov 19, 2016

• #7

If you're interested, here's my own LTspice model for the MC33039 adapter.

 

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• MC33039_Test.asc

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• MC33039g.sub

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• MC33039g.asy

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S

shortbus=

Well-Known Member

Most Helpful Member

• Nov 19, 2016

• #8

Maybe the application note will help you understand better -
https://www.onsemi.com/pub/Collateral/AN1046-D.PDF