Discussion in 'Homework Help' started by menewbie, Feb 14, 2006.

1. menewbie Thread Starter Active Member

Jan 31, 2006
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0
I am trying to design an integrating ADC. So far, I have finished designing the S/H, integrator and comparator. However, I am not sure how to design the control logic. The control logic is the circuit that resets the integrator and the counter. It also controls the switch. I think the control logic should be built by using register but I am not sure if that is correct. Also, is there any book that teaches me how to design a control logic?

2. n9352527 AAC Fanatic!

Oct 14, 2005
1,198
4
Single or dual slope?

Most control logic circuits are just simple state machines (finite) and can be found in most digital design books.

You need to define the necessary sequences, in single slope ADC for example the sequences would be reset the integrator and reset the counter, sample the signal, start integrating and start the counter, stop the counter when the input is equal or more than ref voltage and latch the count and go back to the first step.

You could assign each step to a state on a FSM and trigger the transition with the each associated event. The output of the FSM would be used to trigger any event that is required. Most FSMs are implemented with flip-flops to store the stages and glue logic for transition signals, output signals, etc. Any good digital design book would explain the deign of FSM better.

3. menewbie Thread Starter Active Member

Jan 31, 2006
34
0
It is a dual slope integrating ADC. Thank you for your reply. It helped me a lot. I am reading "Fundamentals of Digital Logic with VHDL Design" by Brown and Vranesic and hopefully I will be able to finish designing this ADC. Thank you again.

4. ehsan34 New Member

Sep 4, 2008
1
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Dear menewbie
Hi