Patent ID: 9025346
Filing Date: 2015-05-05
Classification: H02M

Abstract:
1. A fly-back power converting apparatus, operated in a discontinuous conduction mode (DCM) or a boundary conduction mode (BCM), and comprising: a power transistor, having a first terminal, a second terminal and a control terminal, wherein the first terminal being coupled to an input voltage, and the control terminal receiving a pulse width modulation (PWM) signal; a current detector, coupled in series between the second terminal of the power transistor and a reference ground voltage, and detecting a current output from the second terminal of the power transistor and generating a detecting voltage according to the current; a PWM signal generator, coupled to the current detector and the power transistor, and generating the PWM signal according to a comparing result by comparing the detecting voltage and a standard voltage; and a current limiter, coupled to the PWM signal generator, and generating the standard voltage according to a turn-on time of the power transistor, wherein the current limiter sets a plurality of time points and a plurality of standard voltages corresponding to the time points.