Other Parts Discussed in Thread: UC1834
Hello,
I am using UC1834 as a regulator after flyback DC-DC converter with MOSFET (JANSR2N7550T1) as the pass element. The output specifications for regulator are Vout=4V, Iout=0.2 A to 2.5A. Now as I increase load current from 0.2A to 2.5A, the voltage at input of 1834(Vin+ of 1834 is the same as source terminal of MOSFET)varies from 11V (at light loads) to 6V (at maximum load). If I do not keep that much voltage at MOSFET source (Vin+ of UC1834), then the converter shuts down on inreasing load current. I have 3 questions regarding this problem.
1. Is MOSFET not a suitable device for this application?
2. Is the same phenomenon seen in case BJTs are used as pass element?
3. Is the biasing of MOSFET to operate as pass element not done properly?
