3. Diode Bridge Simulation two

Differences to first simulation:

  • 1N4148, 1N5711 replaced by faster BAS32L (D1, D2, D3, D4, D5, D6, D7, D9)
  • 1N5711 replaced by better forward Vf Schottky BAT54 (D8, D10, D11)
  • 2N3904A replaced by faster BFW92A (Q1, Q2)
  • Skew and AC-bal starts working
  • AC-bal capacitance reduced to 3pF (Cac)
  • parasitic first order low pass on trigger impuls, characteristic avoids rough square wave edges
  • baseline readjusted






The ON transient almost disappeared, OFF transient is still too large.
AC-bal and skew setting trimmers are powerful. DC Baseline is easy to adjust.


Simulation "where are transient fast currents?"


I want to know if I should  solder the diodes D7, D9 close to the diode-bridge-IC or close to the emitters Q1, Q2?

For this I check node "ucq2" from emitter Q2. All currents flowing inside this node are positive - all currents leaving the node are negative.

I(R8) less
I(R19) less
I(R17) less
I(D6) fast transient OFF
I(D3) fast transient OFF
-I(D7) fast transient ON much current
-Ic(Q2) high current ON, OFF

ON t=0.5µs
OFF t= 1.5µs







Result from simulation node ucq2:

better place D7 and D9 close to emitters of Q1 and Q2 reducing influence of parasitic inductance between them. Switching diodes on is easy, switch them off is difficult - a current spike occurs, one reason: u=L*di/dt

Same simulation for node ucq1:

All currents flowing inside this node are positive - all currents leaving the node are negative.

I(R3) less
-I(R6) less
-I(R7) less
-I(D5) fast transient OFF
-I(D4) fast transient OFF
I(D9) fast transient ON much current
-Ic(Q1) high current ON, OFF

ON t=0.5µs
OFF t= 1.5µs





back



Impressum und Haftungsausschluss