Abstract: A flyback converter control architecture is provided in which primary-only feedback techniques are used to ensure smooth startup and detection of fault conditions. During steady-state operation, secondary-side regulation is employed. In addition, current limits are monitored during steady-state operation using primary-only feedback techniques to obviate the need for a secondary-side current sense resistor.

Abstract: A switching power converter is provided that communicates with a mobile device to receive a value of a load detection current. The switching power converter adjusts the cycling of a power switch until a constant current mode of operation is entered with a known output current driving the mobile device. The switching power converter subtracts the load current from the output current to measure a soft-short circuit current.

Abstract: A flyback converter with secondary-side control includes a secondary-side controller configured to emulate a primary-winding current. Based upon the emulated primary-winding current, the secondary-side controller signals a primary-side controller through at least one isolation capacitor to switch off a power switch transistor.

Abstract: A flyback converter is provided that includes a high-side synchronous rectifier switch transistor. A secondary-side synchronous rectifier controller powered by a power supply voltage controls a cycling on and off of the high-side synchronous rectifier switch transistor. An active control of the charging of the power supply voltage uses an auxiliary capacitor that is charged from a charge source while a power switch transistor in a first switching state. When the power switch transistor is in a second switching state that is the complement of the first switching state, the active control coupes the auxiliary capacitor to a power supply capacitor that stores the power supply voltage.

Abstract: A flyback converter is provided that detects a load-transient-produced increase in the output current to more quickly detect and respond to the load transient.

Abstract: A flyback converter includes a synchronous rectifier switch transistor controlled by a controller. The controller cycles the synchronous rectifier switch transistor to lower an output voltage by transferring energy from a secondary-side output capacitor to a primary-side input capacitor.

Abstract: A gate drive control circuit is provided that charges a gate voltage of a power switch transistor during a power switch transistor on-time period. During a first portion of the on-time period, the gate drive control circuit charges the gate voltage through a relatively-low resistance. During a second portion of the on-time period, the gate drive control circuit charges the gate voltage through a relatively-high resistance. Finally, during a third portion of the on-time period, the gate drive control circuit charges the gate voltage through another relatively-low resistance.

Abstract: An active-clamp flyback converter is provided with improved active-clamp switch control that switches on an active-clamp switch at an active-clamp switch on-time that equals a power switch on-time minus a peak charge time for an active-clamp capacitor. The peak charge time is the duration between the switching off of the power switch transistor and when the charging current through the active-clamp capacitor falls to zero. The controller measures this peak charge time following the switching off of the power switch transistor and then applies it to the subsequent switching on of the active-clamp switch so that the active-clamp switch is switched on at the power switch on-time minus the peak charge time.

Abstract: A switching power converter is provided that adaptively changes the on-time period for an auxiliary switch transistor to locate a boundary between sufficient and insufficient energy.

Abstract: A flyback converter is provided that dynamically adjusts a drain threshold voltage for a current cycle of a synchronous rectifier switch transistor based upon operating conditions in a previous cycle of the synchronous rectifier switch transistor. A differential amplifier drives a gate voltage of the synchronous rectifier switch transistor during an on-time of the current cycle so that a drain voltage of the synchronous rectifier switch transistor equals the drain threshold voltage during a regulated portion of the current cycle.

Abstract: A system for turning off a synchronous rectifier (SR) based on a primary switch (PS) turn-on detection in a flyback converter having a primary-side and a secondary-side is disclosed. The system comprises the PS on the primary-side, the SR on the secondary-side, a spike detector, and a SR controller. The SR is configured to produce a drain-to-source voltage (VDS). The spike detector is in signal communication with an output capacitor (Cout) on the secondary-side and the spike detector is configured to detect a voltage spike of an output voltage (VOut) across the Cout that is indicative of the PS being turned-on. The SR controller is in signal communication with the SR and the spike detector and the SR controller is configured to turn-off the SR based on the spike detector detecting the voltage spike of the VOut.

Abstract: A flyback converter communication channel is provided that comprises a pair of capacitors. A transmitter on a first side of a transformer for the flyback converter transmits a transmitter signal over a first one of the capacitors. The transmitter also transmits a complement of the transmitter signal over a second one of the capacitors. A receiver on a second side of the transformer controls a switch transistor responsive to a high-pass-filtered difference of the received signals from the pair of capacitors.

Abstract: An auxiliary winding for a flyback converter includes a floating terminal coupled to ground through a diode. A primary-side controller has a power supply voltage terminal coupled to a remaining terminal of the auxiliary winding and has a voltage sense terminal coupled to the floating terminal.

Abstract: An isolated switching power converter having a primary-side and secondary-side in signal communication with an input and an output is disclosed. The isolated switching power converter comprises a transformer, primary-side switch, secondary-side switch, primary-side controller, and secondary-side controller. The transformer includes a primary-winding and a secondary-winding in signal communication with the input and output. The primary-side switch is in signal communication with the primary-winding and the secondary-side switch is in signal communication with the secondary-winding. The primary-side controller is on the primary-side and the secondary-side controller is on the secondary-side.

Abstract: A standby power system for a flyback converter is disclosed. The flyback converter includes a primary-side, a secondary-side, an output terminal at the secondary-side, and a secondary-side controller, where the output terminal is configured to electrically connect to a load. The standby power system comprises a comparator at the secondary-side, an opto-coupler in signal communication with the primary-side, the secondary-side, and the comparator, and a cable detach detector (or load detector). The cable detach detector is configured to determine whether a device is electrically connected to the flyback converter through a charging cable and to set the flyback converter into a standby mode if the deice is disconnected from the charging cable.

Abstract: A flyback converter is disclosed that includes an auxiliary switch controller that adaptively controls the auxiliary switch for improved zero voltage switching. The auxiliary switch control adaptively adjusts the auxiliary switch on-time period responsive to a transformer reset time for the flyback converter, a resonant oscillation period for a power switch terminal voltage for a power switch transistor, and an on-time period for the power switch transistor to provide the improved zero voltage switching.

Abstract: A flyback converter is provided that compares a drain-to-source voltage of a synchronous rectifier switch transistor to a negative threshold voltage to detect whether the synchronous rectifier switch transistor has a partially-open or an open fault condition. The flyback converter also compares a gate terminal voltage of a gate driver to the synchronous rectifier switch transistor to a positive threshold voltage to detect whether the synchronous rectifier switch transistor has a gate open or a gate short-circuit fault condition.

Abstract: A flyback converter is provided that dynamically adjusts a drain threshold voltage for a current cycle of a synchronous rectifier switch transistor based upon operating conditions in a previous cycle of the synchronous rectifier switch transistor. A differential amplifier drives a gate voltage of the synchronous rectifier switch transistor during an on-time of the current cycle so that a drain voltage of the synchronous rectifier switch transistor equals the drain threshold voltage during a regulated portion of the current cycle.

Abstract: A secondary-side control loop for a flyback converter is provided that generates a secondary-side control signal during normal operation using a compensator. In periods of significant load changes, the compensator is bypassed so that the secondary-side control signal is generated as an open-loop signal.

Abstract: A DALI interface is provided that includes a digital isolator having an input terminal and an output terminal. A DALI bus controlled by a master device controls a binary voltage state of a voltage rail. A DFET couples between the input terminal and the output terminal to control a voltage of the input terminal responsive to the control of the DALI bus by the master device. The digital isolator responds to the control of the input terminal voltage to drive a digital signal through an isolation barrier to control a voltage of the output terminal to control a slave lighting device.