the  phase and frequency  of  LTC3871

C387When LTC3871 is used, the two PWMs phase of its output are not constant at 180 degrees in the case of open loop, and the output frequency is not consistent with the set frequency, and the frequency setting resistance is 34K. When working in the closed loop, its frequency becomes 75K, but the output of the two PWMs are still not 180 degrees, and it do not keep the  phase of 180 degrees.