T
treez
Guest
Hi,
Would you agree that the Two Transistor Forward is best driven like a Full Bridge with 2 diagonal FETs replaced by just diodes? (ie like “half full bridge”)
Then you can use a Bootstrap high side driver without suffering a delay before the Bootstrap capacitor gets charged up. If not done like “half a Full Bridge”, then the delay in charging the bootstrap capacitor means that the error amplifier output gets railed high at startup and then one finds oneself getting startup overcurrents. Would you agree?
Comparison attached (pdfs and LTspice sims) of Two Transistor Forwards with Bootstrap drivers , but one in “half full bridge” mode, the other in “plain bootstrap” mode.
“Plain Bootstrap” is clearly inferior with regards to delayed Bootstrap cap charging at startup, as well as poor light load performance. (since there’s little or no refresh of the bootstrap cap)
Would you agree?
Would you agree that the Two Transistor Forward is best driven like a Full Bridge with 2 diagonal FETs replaced by just diodes? (ie like “half full bridge”)
Then you can use a Bootstrap high side driver without suffering a delay before the Bootstrap capacitor gets charged up. If not done like “half a Full Bridge”, then the delay in charging the bootstrap capacitor means that the error amplifier output gets railed high at startup and then one finds oneself getting startup overcurrents. Would you agree?
Comparison attached (pdfs and LTspice sims) of Two Transistor Forwards with Bootstrap drivers , but one in “half full bridge” mode, the other in “plain bootstrap” mode.
“Plain Bootstrap” is clearly inferior with regards to delayed Bootstrap cap charging at startup, as well as poor light load performance. (since there’s little or no refresh of the bootstrap cap)
Would you agree?