Abstract: A high-voltage (HV) compound switch can include coupling circuitry to help provide better slew rate (dV/dt) control, such as to limit electromagnetic energy radiation during switching, which can cause undesirable EMI. Further, efficiency and on-state resistance can be improved by controllably forward-biasing the “normally on” JFET when the compound switch is in an “on” state. In such an on-state, the JFET temperature can be monitored, such as by monitoring the gate-source junction voltage or the gate current of the JFET. Such temperature information can be used for control or other purposes.

Abstract: A high-voltage (HV) compound switch can include coupling circuitry to help provide better slew rate (dV/dt) control, such as to limit electromagnetic energy radiation during switching, which can cause undesirable EMI. Further, efficiency and on-state resistance can be improved by controllably forward-biasing the “normally on” JFET when the compound switch is in an “on” state. In such an on-state, the JFET temperature can be monitored, such as by monitoring the gate-source junction voltage or the gate current of the JFET. Such temperature information can be used for control or other purposes.

Abstract: A high-voltage (HV) compound switch can include coupling circuitry to help provide better slew rate (dV/dt) control, such as to limit electromagnetic energy radiation during switching, which can cause undesirable EMI. Further, efficiency and on-state resistance can be improved by controllably forward-biasing the “normally on” JFET when the compound switch is in an “on” state. In such an on-state, the JFET temperature can be monitored, such as by monitoring the gate-source junction voltage or the gate current of the JFET. Such temperature information can be used for control or other purposes.

Abstract: A high-voltage (HV) compound switch can include coupling circuitry to help provide better slew rate (dV/dt) control, such as to limit electromagnetic energy radiation during switching, which can cause undesirable EMI. Further, efficiency and on-state resistance can be improved by controllably forward-biasing the “normally on” JFET when the compound switch is in an “on” state. In such an on-state, the JFET temperature can be monitored, such as by monitoring the gate-source junction voltage or the gate current of the JFET. Such temperature information can be used for control or other purposes.

Abstract: Switching regulator methods and systems for supplying output current at a regulated voltage level to a load. The regulator has a primary side that is galvanically isolated from a secondary side. The regulator includes a transformer having a primary winding on the primary side and a secondary winding on the secondary side, coupled to a load. A switch, coupled to the primary winding, controls current flow through the primary winding. A first feedback control loop, responsive only to primary side signal values, regulates a constant average voltage at the output node. An optional second feedback control loop, responsive only to primary side signal values, reduces voltage ringing at the output node.

Abstract: An isolated flyback converter having temperature compensation (TC) uses primary side sensing and an output diode, the output diode having a variable voltage drop related to its temperature. A feedback voltage VFB, proportional to the output voltage VOUT, in a feedback loop is compared to a fixed reference voltage VREF for setting a duty cycle of a power switch, wherein VFB is caused to approximately equal VREF. A TC circuit has a voltage source configured to generate a proportional-to-absolute-temperature voltage VPTAT, wherein VPTAT is at approximately VREF at a calibration temperature T0 and rises as a temperature exceeds T0. The voltage source is connected to the VFB node via a TC resistor RTC, so that at T0 no current flows through RTC. Therefore, the selection of the optimal RTC does not affect the selection of a scaling resistance for generating VFB. The current through RTC at elevated temperatures compensates VOUT.

Abstract: Switching regulator methods and systems for supplying output current at a regulated voltage level to a load. The regulator has a primary side that is galvanically isolated from a secondary side. The regulator includes a transformer having a primary winding on the primary side and a secondary winding on the secondary side, coupled to a load. A switch, coupled to the primary winding, controls current flow through the primary winding. A first feedback control loop, responsive only to primary side signal values, regulates a constant average voltage at the output node. An optional second feedback control loop, responsive only to primary side signal values, reduces voltage ringing at the output node.

Abstract: A flyback controller generates a switching signal for controlling delivery of current into a primary winding of a transformer in a flyback converter. The controller may include an output current monitoring circuit configured to generate a signal representative of an average output current in a secondary winding of the transformer based on a peak input current in the primary winding and a duty cycle of current in the secondary winding. The flyback controller may generate a switching signal that causes a chopped AC voltage from a dimmer control to be converted by the flyback converter into an average output current from a secondary winding of the transformer that is DC isolated from the chopped AC voltage and that varies as a function of the setting of the dimmer control. The flyback controller may not utilize a signal from an opto-isolator.

Abstract: An isolated flyback converter having temperature compensation (TC) uses primary side sensing and an output diode, the output diode having a variable voltage drop related to its temperature. A feedback voltage VFB, proportional to the output voltage VOUT, in a feedback loop is compared to a fixed reference voltage VREF for setting a duty cycle of a power switch, wherein VFB is caused to approximately equal VREF. A TC circuit has a voltage source configured to generate a proportional-to-absolute-temperature voltage VPTAT, wherein VPTAT is at approximately VREF at a calibration temperature T0 and rises as a temperature exceeds T0. The voltage source is connected to the VFB node via a TC resistor RTC, so that at T0 no current flows through RTC. Therefore, the selection of the optimal RTC does not affect the selection of a scaling resistance for generating VFB. The current through RTC at elevated temperatures compensates VOUT.

Abstract: A powered LED circuit may include a power supply configured to generate and deliver an output current at a controllable average value with a substantial ripple component, one or more LEDs connected together, and a ripple reduction circuit connected to the power supply and to the one or more LEDs. The ripple reduction circuit may have a current regulator connected in series with the one or more LEDs which is configured to substantially reduce fluctuations in the current which flows through the one or more LEDs due to the ripple component of the output current, but not fluctuations in the current which flows through the one or more LEDs due to changes in the average value of the output current.

Abstract: A flyback controller may generate a switching signal for controlling the delivery of input current into a primary winding of a transformer in a flyback converter that has a secondary winding in the transformer and that is driven by AC output from a dimmer control that is chopped at a phase angle based on a setting of the dimmer control. The flyback controller may include a tracking input configured to receive a dimmer output tracking signal that is representative of the instantaneous magnitude of the output from the dimmer control. The flyback controller may include an averaging circuit configured to average the dimmer output tracking signal so as to generate an average dimmer output signal that is representative of a time-averaged value of the dimmer output tracking signal. The flyback controller may be configured to cause the average output current in the secondary winding of the transformer to vary as a function of the average dimmer output signal when the phase angle exceeds a threshold.

Abstract: An LED driver circuit that includes a buck-mode boost converter that provides a regulated output current and that requires only a single connection to each channel of LEDs. The buck-mode boost controller may include a current regulator that includes an integrator. The current regulator may be configured to integrate a difference between a reference signal that is representative of the desired level of the average current through the electronic power switch and a detected signal that is representative of the actual current that is being delivered to the buck-mode boost circuit through the electronic power switch. The reference signal to the integrator may not change during operation of the buck-mode converter. The current regulator may be configured to deactivate the integrator and/or to disconnect the detected signal from the integrator while the electronic power switch is off.

Abstract: A flyback controller may receive a chopped and rectified AC voltage from a dimmer control, each cycle of which may have a controllable off period that is substantially attenuated but not always zero due to leakage of the dimmer control, and a controllable on period that substantially tracks the AC voltage. The flyback controller may include a control circuit configured to generate a switching signal based on the signal from the dimmer input. The switching signal may controllably oscillate between its on and off states during the on periods of the chopped and rectified AC voltage so as to controllably regulate current that is delivered by a secondary winding of a transformer in a flyback converter. The switching signal may be in the on state during the off periods of the chopped and rectified AC voltage, thereby preventing a voltage build up from the dimmer control leakage.

Abstract: An LED driver circuit that includes a buck-mode boost converter that provides a regulated output current and that requires only a single connection to each channel of LEDs. The buck-mode boost controller may include a current regulator that includes an integrator. The current regulator may be configured to integrate a difference between a reference signal that is representative of the desired level of the average current through the electronic power switch and a detected signal that is representative of the actual current that is being delivered to the buck-mode boost circuit through the electronic power switch. The reference signal to the integrator may not change during operation of the buck-mode converter. The current regulator may be configured to deactivate the integrator and/or to disconnect the detected signal from the integrator while the electronic power switch is off.

Abstract: A powered LED circuit may include a power supply configured to generate and deliver an output current at a controllable average value with a substantial ripple component, one or more LEDs connected together, and a ripple reduction circuit connected to the power supply and to the one or more LEDs. The ripple reduction circuit may have a current regulator connected in series with the one or more LEDs which is configured to substantially reduce fluctuations in the current which flows through the one or more LEDs due to the ripple component of the output current, but not fluctuations in the current which flows through the one or more LEDs due to changes in the average value of the output current.

Abstract: A flyback controller generates a switching signal for controlling delivery of current into a primary winding of a transformer in a flyback converter. The controller may include an output current monitoring circuit configured to generate a signal representative of an average output current in a secondary winding of the transformer based on a peak input current in the primary winding and a duty cycle of current in the secondary winding. The flyback controller may generate a switching signal that causes a chopped AC voltage from a dimmer control to be converted by the flyback converter into an average output current from a secondary winding of the transformer that is DC isolated from the chopped AC voltage and that varies as a function of the setting of the dimmer control. The flyback controller may not utilize a signal from an opto-isolator.

Abstract: A flyback controller-may include a dimmer input configured to receive a chopped and rectified AC voltage. Each cycle of the signal may have an off period which is substantially attenuated but not always zero due to leakage of a dimmer control from which the chopped AC voltage originates, and an on period which substantially tracks the AC voltage. The ratio of the off period to the on period may be dependent upon a setting of the dimmer control. The flyback controller may include a control circuit configured to generate a switching signal based on the signal from the dimmer input. The switching signal may controllably oscillate between its on and off states during the on periods of the chopped and rectified AC voltage so as to controllably regulate current that is delivered by a secondary winding of a transformer in a flyback converter.

Abstract: A flyback controller may generate a switching signal for controlling the delivery of input current into a primary winding of a transformer in a flyback converter that has a secondary winding in the transformer and that is driven by AC output from a dimmer control that is chopped at a phase angle based on a setting of the dimmer control. The flyback controller may include a tracking input configured to receive a dimmer output tracking signal that is representative of the instantaneous magnitude of the output from the dimmer control. The flyback controller may include an averaging circuit configured to average the dimmer output tracking signal so as to generate an average dimmer output signal that is representative of a time-averaged value of the dimmer output tracking signal. The flyback controller may be configured to cause the average output current in the secondary winding of the transformer to vary as a function of the average dimmer output signal when the phase angle exceeds a threshold.