A new topology of asymmetric half bridge for 135W-level type-C power delivery application

Abstract

This paper presents a new topology of asymmetric half bridge which can be called capacitor improved-asymmetric half bridge(CI-AHB) by adding a DC blocking capacitor adjacent to the leakage inductance for 135W type-c power delivery applications. Its detailed operation principle is shown and explained briefly. The clamping capacitor for CI-AHB stores energy when the main switch is on. Furthermore, the main switch stress for CI-AHB is low, which allows higher transformer ratio with lower voltagestress synchronous rectifier (SR) FET. The efficiency of CI-AHB under different conditions is shown theoretically. These features help CI-AHB topology have better efficiency for over 100W level adaptor applications with power factor correction (PFC) function of constant dc bus voltage 380V input. Finally, a 135W commercial-level prototypes, PFC with CI-AHB (95.9%) was made (16.34w/inch3 with case) with both EMI and thermal pass. A state-of-the-art summary is finally given on efficiency and density of 135W power delivery (PD) adaptors.