LNK306 Problem
Posted by: xabingy
on
I designed a +15VDC power following AN37. But I got a +3.5V output voltage.
BP pin voltage are 9.2V, and FB pin voltage are 3.6V.
Rfb = 16K
Rbias = 2.2K
Cbp = 0.1uF
Cfb = 0.33uF
Dfw = STTH1R06A
Dfb = 1N4007
Co = 100uF
Why?
I re-measured Vbp and Vfb against device source.
Results are:
Vbp = 5.8V
Vfb = 0.3V
Does it means that coil L is far less than 1.5mH?
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I re-measured Vbp and Vfb against device source.
Results are:
Vbp = 5.8V
Vfb = 0.3V
Does it means that coil L is far less than 1.5mH?
Bp and FB voltages are not right -- they would need to be measured with respect to source of device but this cannot be done when device is switching since probe will introduce noise.
A schematic of your design would be helpful.