Abstract: Disclosed herein are synchronous rectifier control techniques for Discontinuous Current Mode (DCM) converters. These techniques may be particularly advantageous where the current shape is triangular in nature with a fixed down-slope. Such converters may include DCM flyback converters and DCM buck converters. The proposed control techniques can reduce body diode conduction of the synchronous rectifier and optimize turn-off timing, while negating the effect of parasitic circuit elements. These techniques may also help simplify the control of synchronous rectifiers operated in parallel mode. Finally, such techniques may also help achieve higher performance in variable output voltage converters and converters that operate at high switching frequencies.

Abstract: Disclosed herein are synchronous rectifier control techniques for Discontinuous Current Mode (DCM) converters. These techniques may be particularly advantageous where the current shape is triangular in nature with a fixed down-slope. Such converters may include DCM flyback converters and DCM buck converters. The proposed control techniques can reduce body diode conduction of the synchronous rectifier and optimize turn-off timing, while negating the effect of parasitic circuit elements. These techniques may also help simplify the control of synchronous rectifiers operated in parallel mode. Finally, such techniques may also help achieve higher performance in variable output voltage converters and converters that operate at high switching frequencies.

Abstract: Systems and methods for operating improved flyback converters are disclosed, in which leakage energy is returned to the input power source rather than to the output load, while still achieving zero voltage switching (i.e., ZVS) operation. In some embodiments, the improved converters may transfer the energy stored in the leakage inductance to a snubber capacitor(s) at the instant of turning off of the control switch. Further, the improved converter embodiments may also retain the stored energy in the snubber capacitor(s) when the power is being delivered to the load by the secondary circuits. The improved converter embodiments may start the transfer of leakage energy stored in the snubber capacitor(s) to the primary winding once the energy stored in the transformer is delivered to the load. Finally, the improved converter embodiments may intelligently control their active clamp switches such that all leakage inductance energy is returned to the input source.

Abstract: Systems and methods for operating improved flyback converters are disclosed, in which leakage energy is returned to the input power source rather than to the output load, while still achieving zero voltage switching (i.e., ZVS) operation. In some embodiments, the improved converters may transfer the energy stored in the leakage inductance to a snubber capacitor(s) at the instant of turning off of the control switch. Further, the improved converter embodiments may also retain the stored energy in the snubber capacitor(s) when the power is being delivered to the load by the secondary circuits. The improved converter embodiments may start the transfer of leakage energy stored in the snubber capacitor(s) to the primary winding once the energy stored in the transformer is delivered to the load. Finally, the improved converter embodiments may intelligently control their active clamp switches such that all leakage inductance energy is returned to the input source.

Abstract: This disclosure describes a flyback converter with a series-parallel mode (SPM) active clamp. The active clamp, coupled in parallel with the primary coil, may include a clamp switch, two or more snubber capacitors, and associated diodes. The active clamp may be configured to absorb and retain the leakage energy from the leakage inductance of the flyback converter. The clamp switch may be turned on selectively as the primary switch approaches one of a plurality peak values to adjust frequencies of the switching devices. With the active clamp circuit, the flyback converter may first re-capture the leakage energy in the active clamp circuit and then recover it back to the power source.

Abstract: Disclosed herein are synchronous rectifier control techniques for Discontinuous Current Mode (DCM) converters. These techniques may be particularly advantageous where the current shape is triangular in nature with a fixed down-slope. Such converters may include DCM flyback converters and DCM buck converters. The proposed control techniques can reduce body diode conduction of the synchronous rectifier and optimize turn-off timing, while negating the effect of parasitic circuit elements. These techniques may also help simplify the control of synchronous rectifiers operated in parallel mode. Finally, such techniques may also help achieve higher performance in variable output voltage converters and converters that operate at high switching frequencies.

Abstract: Systems and methods for operating improved flyback converters are disclosed, in which leakage energy is returned to the input power source rather than to the output load, while still achieving zero voltage switching (i.e., ZVS) operation. In some embodiments, the improved converters may transfer the energy stored in the leakage inductance to a snubber capacitor(s) at the instant of turning off of the control switch. Further, the improved converter embodiments may also retain the stored energy in the snubber capacitor(s) when the power is being delivered to the load by the secondary circuits. The improved converter embodiments may start the transfer of leakage energy stored in the snubber capacitor(s) to the primary winding once the energy stored in the transformer is delivered to the load. Finally, the improved converter embodiments may intelligently control their active clamp switches such that all leakage inductance energy is returned to the input source.

Abstract: A flyback converter can include an auxiliary winding magnetically coupled to the secondary (output) for sensing a reflected output voltage. A controller can operate a power switch of the flyback converter in a burst mode to deliver a number of pulses, causing the output voltage to reach a threshold, and thereafter suspend switching for a predetermined time period before delivering a further number of pulses. The delivered number of pulses can be counted, and, responsive to a determination that the count is less than a predetermined minimum number of pulses, the predetermined time period can be increased. Responsive to a determination that the count is greater than a predetermined maximum number of pulses, the predetermined time period can be decreased.

Abstract: A flyback converter can include an auxiliary winding magnetically coupled to the secondary (output) for sensing a reflected output voltage. A controller can operate a power switch of the flyback converter in a burst mode to deliver a number of pulses, causing the output voltage to reach a threshold, and thereafter suspend switching for a predetermined time period before delivering a further number of pulses. The delivered number of pulses can be counted, and, responsive to a determination that the count is less than a predetermined minimum number of pulses, the predetermined time period can be increased. Responsive to a determination that the count is greater than a predetermined maximum number of pulses, the predetermined time period can be decreased.

Abstract: This disclosure describes a flyback converter with a series-parallel mode (SPM) active clamp. The active clamp, coupled in parallel with the primary coil, may include a clamp switch, two or more snubber capacitors, and associated diodes. The active clamp may be configured to absorb and retain the leakage energy from the leakage inductance of the flyback converter. The clamp switch may be turned on selectively as the primary switch approaches one of a plurality peak values to adjust frequencies of the switching devices. With the active clamp circuit, the flyback converter may first re-capture the leakage energy in the active clamp circuit and then recover it back to the power source.

Abstract: Systems and methods for operating improved flyback converters are disclosed, in which leakage energy is returned to the input power source rather than to the output load, while still achieving zero voltage switching (i.e., ZVS) operation. In some embodiments, the improved converters may transfer the energy stored in the leakage inductance to a snubber capacitor(s) at the instant of turning off of the control switch. Further, the improved converter embodiments may also retain the stored energy in the snubber capacitor(s) when the power is being delivered to the load by the secondary circuits. The improved converter embodiments may start the transfer of leakage energy stored in the snubber capacitor(s) to the primary winding once the energy stored in the transformer is delivered to the load. Finally, the improved converter embodiments may intelligently control their active clamp switches such that all leakage inductance energy is returned to the input source.

Abstract: Systems and methods for operating improved flyback converters are disclosed, in which leakage energy is returned to the input power source rather than to the output load, while still achieving zero voltage switching (i.e., ZVS) operation. In some embodiments, the improved converters may transfer the energy stored in the leakage inductance to a snubber capacitor(s) at the instant of turning off of the control switch. Further, the improved converter embodiments may also retain the stored energy in the snubber capacitor(s) when the power is being delivered to the load by the secondary circuits. The improved converter embodiments may start the transfer of leakage energy stored in the snubber capacitor(s) to the primary winding once the energy stored in the transformer is delivered to the load. Finally, the improved converter embodiments may intelligently control their active clamp switches such that all leakage inductance energy is returned to the input source.

Abstract: Systems and methods for operating improved flyback converters are disclosed, in which leakage energy is returned to the input power source rather than to the output load, while still achieving zero voltage switching (i.e., ZVS) operation. In some embodiments, the improved converters may transfer the energy stored in the leakage inductance to a snubber capacitors) at the instant of turning off of the control switch. Further, the improved converter embodiments may also retain the stored energy in the snubber capacitor(s) when the power is being delivered to the load by the secondary circuits. The improved converter embodiments may start the transfer of leakage energy stored in the snubber capacitor(s) to the primary winding once the energy stored in the transformer is delivered to the load. Finally, the improved converter embodiments may intelligently control their active clamp switches such that all leakage inductance energy is returned to the input source.

Abstract: Systems and methods for operating improved flyback converters are disclosed, in which leakage energy is returned to the input power source rather than to the output load, while still achieving zero voltage switching (i.e., ZVS) operation. In some embodiments, the improved converters may transfer the energy stored in the leakage inductance to a snubber capacitor(s) at the instant of turning off of the control switch. Further, the improved converter embodiments may also retain the stored energy in the snubber capacitor(s) when the power is being delivered to the load by the secondary circuits. The improved converter embodiments may start the transfer of leakage energy stored in the snubber capacitor(s) to the primary winding once the energy stored in the transformer is delivered to the load. Finally, the improved converter embodiments may intelligently control their active clamp switches such that all leakage inductance energy is returned to the input source.

Abstract: Systems and methods for operating improved flyback converters are disclosed, in which leakage energy is returned to the input power source rather than to the output load, while still achieving zero voltage switching (i.e., ZVS) operation. In some embodiments, the improved converters may transfer the energy stored in the leakage inductance to a snubber capacitor(s) at the instant of turning off of the control switch. Further, the improved converter embodiments may also retain the stored energy in the snubber capacitor(s) when the power is being delivered to the load by the secondary circuits. The improved converter embodiments may start the transfer of leakage energy stored in the snubber capacitor(s) to the primary winding once the energy stored in the transformer is delivered to the load. Finally, the improved converter embodiments may intelligently control their active clamp switches such that all leakage inductance energy is returned to the input source.

Abstract: Systems and methods for operating improved flyback converters are disclosed, in which leakage energy is returned to the input power source rather than to the output load, while still achieving zero voltage switching (i.e., ZVS) operation. In some embodiments, the improved converters may transfer the energy stored in the leakage inductance to a snubber capacitor(s) at the instant of turning off of the control switch. Further, the improved converter embodiments may also retain the stored energy in the snubber capacitor(s) when the power is being delivered to the load by the secondary circuits. The improved converter embodiments may start the transfer of leakage energy stored in the snubber capacitor(s) to the primary winding once the energy stored in the transformer is delivered to the load. Finally, the improved converter embodiments may intelligently control their active clamp switches such that all leakage inductance energy is returned to the input source.

Abstract: Systems and methods for operating improved flyback converters are disclosed, in which leakage energy is returned to the input power source rather than to the output load, while still achieving zero voltage switching (i.e., ZVS) operation. In some embodiments, the improved converters may transfer the energy stored in the leakage inductance to a snubber capacitor(s) at the instant of turning off of the control switch. Further, the improved converter embodiments may also retain the stored energy in the snubber capacitor(s) when the power is being delivered to the load by the secondary circuits. The improved converter embodiments may start the transfer of leakage energy stored in the snubber capacitor(s) to the primary winding once the energy stored in the transformer is delivered to the load. Finally, the improved converter embodiments may intelligently control their active clamp switches such that all leakage inductance energy is returned to the input source.

Abstract: A switching power converter has at least one electronic power switch. To minimize switching losses and optimize efficiency, the gate drive voltage level used to drive the electronic power switch is optimized. In an aspect, a digital controller generates optimizes the gate drive voltage using efficiency optimization algorithms, which in an aspect are programmed in the digital controller. In accordance with an aspect of the present disclosure, the switching power supply has at least two electronic power switches coupled in parallel. Optimization algorithms are used to determine the optimum number of switched electronic power switches that are actively being switched at a given time in order to achieve optimized efficiency for condition changes, such as input voltage variation, load and environmental temperature changes. In an aspect, the algorithms are programmed in a digital controller chip.

Abstract: A power converter includes a controller having at least one input for monitoring a rate of change of an operating parameter of the power converter. The controller is configured for comparing the monitored rate of change of the operating parameter with an allowable rate of change for the operating parameter, and for generating a fault signal when the monitored rate of change of the operating parameter deviates from the allowable rate of change for the operating parameter. The operating parameter for which the rate of change is monitored may be, for example, a temperature, a current and/or a voltage in the power converter.

Abstract: A power converter includes a controller and at least one output terminal for providing an output voltage and an output current to a load. The controller is configured for monitoring the output voltage and the output current and calculating an efficiency of the power converter based on the monitored output voltage and output current. The controller is also configured to generate a fault signal after detecting a degradation in the power converter efficiency.