That may sound like a strange question.
Jim Williams at Linear Technology published some very nice current tracings for the inductor in a switch-mode power supply (see: AN-35), which show the beginning of a rapid increase in current at the end of the on-cycle, as the core nears saturation. I made an inductive probe to study that property. Of course, one sees the rapid increase in current when the "switch" to the inductor turns on, but as the change in current tapers off, the probe signal falls almost to zero, as expected.
I want to see whether one can detect the increase in current with saturation, when that is superimposed on the decrease mentioned above.
Tektronix has a solution to that (See: various Tek patents), which uses a combination of a Hall sensor and coil. I am experimenting with doing it electronically (mathematically).
Attached are some tracings of inductor current in a mock switching regulator. The top tracing is current to the inductor measured across a sense resistor. The bottom tracing is my probe including a differentiation component.
Now, I want to test it with a known, saturated condition. For practical reasons, I am limited to about 2A at 6V using my regular bench supply. However, I am willing to cobble up something else, if I thought it had a reasonable chance of success. One thought was to put a second winding on the inductor and use that winding to add a straight DC component to the magnetic field. Any suggestions for size and the magnitude of currents that will be necessary or alternative ways to get a known saturated condition?
Thanks. John
Jim Williams at Linear Technology published some very nice current tracings for the inductor in a switch-mode power supply (see: AN-35), which show the beginning of a rapid increase in current at the end of the on-cycle, as the core nears saturation. I made an inductive probe to study that property. Of course, one sees the rapid increase in current when the "switch" to the inductor turns on, but as the change in current tapers off, the probe signal falls almost to zero, as expected.
I want to see whether one can detect the increase in current with saturation, when that is superimposed on the decrease mentioned above.
Tektronix has a solution to that (See: various Tek patents), which uses a combination of a Hall sensor and coil. I am experimenting with doing it electronically (mathematically).
Attached are some tracings of inductor current in a mock switching regulator. The top tracing is current to the inductor measured across a sense resistor. The bottom tracing is my probe including a differentiation component.
Now, I want to test it with a known, saturated condition. For practical reasons, I am limited to about 2A at 6V using my regular bench supply. However, I am willing to cobble up something else, if I thought it had a reasonable chance of success. One thought was to put a second winding on the inductor and use that winding to add a straight DC component to the magnetic field. Any suggestions for size and the magnitude of currents that will be necessary or alternative ways to get a known saturated condition?
Thanks. John