Constant current boost converter problems

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SUMMARY

The forum discussion centers on the design challenges faced when creating a constant current driver for a Xenon arc lamp using a TL494 controller. The user reports issues with audible noise, current surges, and instability in output current, which vary with load conditions. Suggestions include improving PCB layout to reduce ground loops, adding inductors for stabilizing arc current, and implementing low-pass filtering on the current feedback to mitigate spikes. The discussion emphasizes the importance of proper design practices in switching regulators to achieve stable performance.

PREREQUISITES
  • Understanding of TL494 PWM controller operation
  • Knowledge of switching regulator design principles
  • Familiarity with PCB layout techniques for high-frequency applications
  • Experience with inductive load management in power electronics
NEXT STEPS
  • Research proper PCB layout techniques for switching regulators
  • Learn about low-pass filtering methods for current feedback in power circuits
  • Explore the use of inductors in stabilizing arc lamps
  • Investigate simulation tools like LTspice for modeling switching converter behavior
USEFUL FOR

Electrical engineers, hobbyists designing power supplies, and anyone involved in high-frequency switching regulator applications, particularly those working with inductive loads like Xenon arc lamps.

  • #31
I recommend we isolate the lamp with a close resistor load, measure the load on initial lamp start up as it will, I would think drop once its fully on. Then try a potentiometer on the load side and check the signal behavior. If the behavior improves then we can look into a means to regulate it. If it doesn't improve then we know were still configured wrong on the 494
 
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  • #32
jim hardy said:
Are above traces with lamp load or resistor load?
What is the yellow trace now - current through load or voltage across output capacitor?
5Ω resistive load.
The traces are across current feedback output - 20:1 amp of current across 0.01Ω sense resistor, with RC filter of 100Ω and 0.1μF.

jim hardy said:
So - what region of your closed loop has a response time around a half millisecond?
The ignitor transformer?
It's 200μH worth of choke in series with the load.


All in all, I'm likely to give up on this design, and try a CV boost followed by CC buck instead.
So, thanks all for help.
 

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