US RE50,277 E1
Power converter and method of control thereof
Haibin Song, Shanghai (CN); Laszlo Huber, Cary, NC (US); Daofei Xu, Shanghai (CN); Alpha Zhang, Shanghai (CN); Milan M. Jovanovic, Cary, NC (US); and Chien-Chung Chang, Taoyuan (TW)
Assigned to Delta Electronics, Inc., Neihu (TW)
Filed by Delta Electronics, Inc., Taipei (TW)
Filed on Jul. 17, 2020, as Appl. No. 16/931,904.
Application 16/931,904 is a reissue of application No. 15/428,885, filed on Feb. 9, 2017, granted, now 10,141,853, issued on Nov. 27, 2018.
Int. Cl. H02M 3/335 (2006.01); H02M 1/00 (2007.01); H02M 1/32 (2007.01); H02M 1/34 (2007.01)
CPC H02M 3/33569 (2013.01) [H02M 1/32 (2013.01); H02M 1/34 (2013.01); H02M 3/33592 (2013.01); H02M 1/0009 (2021.05); H02M 1/0048 (2021.05); H02M 1/0054 (2021.05); H02M 1/344 (2021.05); Y02B 70/10 (2013.01)] 41 Claims
OG exemplary drawing
 
[ 22. A flyback power converter receiving an input voltage and providing an output voltage and an output current to a load, comprising:
a transformer having a primary winding and a secondary winding, the output voltage and the output current being provided to the load from the secondary winding;
a first switch coupled to the primary winding, the first switch coupling the input voltage across the primary winding when the first switch is turned on;
a clamp circuit comprising a second switch, a clamp capacitor, and a clamp resistor, the clamp resistor being connected with the clamp capacitor in parallel and being connected with the second switch in series; and
a control block comprising a controller and a power management unit and configured to provide a first control signal for regulating the output voltage or the output current by periodically turning on and off the first switch and a second control signal for the second switch for enabling or disabling switching of the second switch based on the flyback power converter's operating conditions,
wherein the clamp circuit is configured to:
if the flyback power converter's operating conditions specify an active clamp, the second switch is enabled by the second control signal and both the first switch and the second switch are modulated by the first control signal and the second control signal, respectively, to provide the active clamp, such that energy stored in a leakage inductance of the flyback power converter is at least partially recycled and used to achieve zero-voltage-switching (ZVS) for the first switch; and
if the flyback power converter's operating conditions specify a passive clamp, the second switch is disabled by the second control signal and the first switch is modulated by the first control signal, to provide the passive clamp, such that the energy stored in the leakage inductance of the flyback power converter is dissipated in the clamp resistor. ]