AnsweredAssumed Answered

ADP1051 SR max. duty issue

Question asked by on Nov 19, 2014
Latest reply on Nov 19, 2014 by james.xie



I'm using ADP1051 to desing an phase shift full bridge for DC to DC converter (380V to 12V); but now I'm facing a SR PWM issue.


Below is the PWM setting, the SR1 rising edge follows the OUTA falling edge with very small delay and the max SR duty is around 9us

GUI setting.PNG

During the testing, I have the SR max.duty problem which is limited in 5.48us.  The SR duty is limited in 5.48uS and can NOT modulate to following the OUTA PWM falling edge.

Using mosfet.PNG

I replace the SR1 MOSFET with diode, the SR PWM duty become correct. the SR duty will modulate by following the OUTA PWM falling edge.

Using Diode.PNG

Please suggest the solution for this issue. How come the SR1 PWM works correctly when use diode in SR place; but have problem when using the MOSFET in SR place !?