Swend
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Pulse charging capacitor through diode - problems
Hi friends.
I am trying to pulse charge a few capacitors through diodes, here is the schematic below. Q3 and Q4 are both OFF in this test. C6 is the problem area.
Input pulse
Voltage across C4 with ref. to 0 (zero) everything is as expected.
Voltage across C6 with ref. to 0 (zero), now why can't this be like C4? the only difference between C4 and C6, is that when charging C6 there is an extra diode D3 in the charging path. If I short out D3, then C6 trace becomes exactly like C4. And I tried several other diodes, same problem.
I measured the voltage drop over D3, according to the datasheet the Vfm is 1.7V and I measured it to 410mV - so it never turns on, why?
Hi friends.
I am trying to pulse charge a few capacitors through diodes, here is the schematic below. Q3 and Q4 are both OFF in this test. C6 is the problem area.
Input pulse
Voltage across C4 with ref. to 0 (zero) everything is as expected.
Voltage across C6 with ref. to 0 (zero), now why can't this be like C4? the only difference between C4 and C6, is that when charging C6 there is an extra diode D3 in the charging path. If I short out D3, then C6 trace becomes exactly like C4. And I tried several other diodes, same problem.
I measured the voltage drop over D3, according to the datasheet the Vfm is 1.7V and I measured it to 410mV - so it never turns on, why?