Designing Comparator Circuits with 2 Different Thresholds

  • Thread starter Thread starter likephysics
  • Start date Start date
  • Tags Tags
    Comparator
Click For Summary
SUMMARY

The discussion focuses on designing a comparator circuit with two distinct switching thresholds: Vth+ = 3V, Vth- = 1V for the first threshold, and Vth+ = 8V, Vth- = 3V for the second. The user attempted to modify the reference voltage but faced issues with both thresholds moving in tandem. A T-network was introduced in the hysteresis feedback to manage the thresholds, but the user struggled with the mathematical aspects of the T-network. An alternative solution proposed involves using three comparators to handle each threshold reference level, simplifying the design by employing a digital logic finite state machine to manage hysteresis.

PREREQUISITES
  • Understanding of comparator circuits and their configurations
  • Knowledge of hysteresis in electronic circuits
  • Familiarity with T-network design and analysis
  • Basic principles of digital logic and finite state machines
NEXT STEPS
  • Study the design and implementation of comparator circuits with multiple thresholds
  • Learn about T-network configurations and their mathematical analysis
  • Explore digital logic finite state machines for managing hysteresis
  • Review practical examples of comparator circuits in analog design
USEFUL FOR

Electronics engineers, circuit designers, and students interested in advanced comparator circuit design and hysteresis management techniques.

likephysics
Messages
638
Reaction score
4
I am trying to design a comparator which is required to have 2 different switching thresholds.

The comparator +ve input is connected to a signal source (triangle wave). The -ve is connected to a reference voltage.

The first threshold will be say Vth+ = 3V and Vth- = 1V
and second threshold Vth+ = 8V and Vth-= 3V

I tried changing the reference voltage. But both levels either go up or down.
I added a T network in the hysteresis feedback network. The grounded resistor in t network would be open for the first set of threshold and it would be grounded for the second set. It helps a bit. I can't figure out the math of t network.

Any other ideas?
 
Engineering news on Phys.org
The easiest way is to allocate 3 comparators at each threshold reference level and do the hysteresis in a digital logic finite state-machine. That eliminates the variability and complexity of feedback loops and delays.
 
Can you show us your circuit?
 

Thread 'uA709 op amp compensation'

Most likely this can only be answered by an "old timer". I am making measurements on an uA709 op amp (metal can). I would like to calculate the frequency rolloff curves (I can measure them). I assume the compensation is via the miller effect. To do the calculations I would need to know the gain of the transistors and the effective resistance seen at the compensation terminals, not including the values I put there. Anyone know those values?
View full post »

Similar threads

Window Comparator: Understanding the Output Behavior and Common Errors
  • · Replies 5 ·
Replies
5
Views
3K
Alternator torque when connected to a phase-shifted AC source
  • · Replies 3 ·
Replies
3
Views
2K
How to Measure PCB Impedance and Component Coupling?
  • · Replies 12 ·
Replies
12
Views
2K
Engineering Practical design of an inverting Schmitt trigger with noise tolerance
  • · Replies 21 ·
Replies
21
Views
3K
Circuit breaker, clearing a fault current
  • · Replies 50 ·
2
Replies
50
Views
9K
How to use a bench power supply
  • · Replies 9 ·
Replies
9
Views
4K
Beginner circuits / ↓ the voltage & ↑ the efficiency
  • · Replies 12 ·
Replies
12
Views
2K
AC generator, current and ground
  • · Replies 26 ·
Replies
26
Views
3K
Understanding operation of specific SMPS example (is it a flyback?)
  • · Replies 2 ·
Replies
2
Views
2K
Line and Phase voltages differences
  • · Replies 1 ·
Replies
1
Views
2K