Patent application number | Description | Published |
20130063185 | Apparatus and Method for Pulse Width Modulation Control for Switching Power Converters - An embodiment apparatus comprises a first two-piecewise linear approximation generator and a second two-piecewise linear approximation generator coupled to an output of the first two-piece wise linear approximation generator. The second two-piecewise linear approximation generator generates a dead time inversely proportional to the output of the first two-piece wise linear approximation generator. A gate drive generator is configured to generate a primary switch drive signal and an auxiliary switch drive signal complementary to the primary switch drive signal. In addition, the dead time between the primary switch drive signal and the auxiliary switch drive signal is adjustable when the power converter operates in a light load condition. | 03-14-2013 |
20130063982 | Soft Transition Apparatus and Method for Switching Power Converters - An embodiment apparatus comprises a secondary synchronous rectifier and a secondary gate drive controller. The secondary gate drive controller coupled to a transformer winding comprises a secondary synchronous rectifier soft start signal generator configured to generate a plurality of soft start pulses, a pulse width modulation generator configured to generate a forward switch drive signal and a freewheeling switch drive signal based upon a signal across the transformer winding and a soft transition generator configured to generate a soft start freewheeling switch drive signal by gradually releasing the freewheeling switch drive signal during a soft start process. | 03-14-2013 |
20130063985 | Adaptive Dead Time Control Apparatus and Method for Switching Power Converters - An embodiment apparatus comprises a secondary synchronous rectifier and a secondary gate drive controller coupled to a transformer winding. The secondary gate drive controller is configured to generate a forward gate drive signal for the forward switch and generate a freewheeling gate drive signal for the freewheeling switch, wherein the secondary gate drive controller generates a dead time between the forward gate drive signal and the freewheeling gate drive signal. | 03-14-2013 |
20150109824 | Apparatus and Method for High Efficiency Resonant Converters - A converter comprises an input stage coupled to a power source, wherein the input stage comprises a plurality of power switches, a resonant tank coupled to the plurality of power switches, a transformer coupled to the resonant tank, an output stage coupled to the transformer, an efficiency point tracking indicator coupled to the converter, a detector coupled to the efficiency point tracking indicator and a control circuit configured to receive an efficiency point tracking signal from the detector and adjust a switching frequency of the power switches based upon the efficiency point tracking signal. | 04-23-2015 |
20150124487 | Adjustable Resonant Apparatus for Power Converters - An apparatus comprises a first series resonant inductor coupled to a switching network and a transformer, a first series resonant capacitor coupled to the switching network and the transformer, a first parallel inductor coupled to the switching network through the first series resonant inductor and the first series resonant capacitor, a resonant frequency adjusting device coupled to the switching network and the transformer and a switch connected in series with the resonant frequency adjusting device. | 05-07-2015 |
20150124488 | Startup Method and System for Resonant Converters - A method comprises providing a resonant converter comprising a switching network comprising a plurality of switches, a resonant tank coupled between the switching network and a transformer, wherein the resonant tank comprises a series resonant inductor coupled to a switching network and the transformer and a series resonant capacitor coupled to the switching network and the transformer and a driver having an adjustable bias voltage and in response to a startup process of the resonant converter, configuring the switching network to operate a switching frequency higher than a resonant frequency of the resonant tank. | 05-07-2015 |
20150124489 | Current Sensing Apparatus for Power Converters - An apparatus comprises a magnetic device coupled to an inductor-inductor-capacitor (LLC) resonant converter, an ac current sensing circuit coupled to the magnetic device, an average current sensing circuit coupled to the ac current sensing circuit and a reference voltage source coupled to the average current sensing circuit, wherein the reference voltage source is configured such that a magnitude of an average signal from the average current sensing circuit is greater than a voltage level of the reference voltage source. | 05-07-2015 |
20150124492 | Apparatus and Method for High Efficiency LLC Resonant Converters - A method comprises providing a resonant converter, wherein the resonant converter comprises an input switch network coupled to a power source, wherein the input switch network comprises a plurality of power switches, a resonant tank coupled to the plurality of power switches, a transformer coupled to the resonant tank and an output stage coupled to the transformer, wherein the output stage comprises a synchronous rectifier formed by a first switch and a second switch, detecting a drain voltage of the first switch, comparing the drain voltage with a predetermined voltage threshold, wherein the drain voltage is coupled to a negative input of a comparator and the predetermined voltage threshold is coupled to a positive input of the comparator, generating a logic state based upon an output of the comparator and adjusting, by a control circuit, a switching frequency of the resonant converter based upon the logic state. | 05-07-2015 |