Abstract: A method includes receiving a sense signal having multiple pulses, where the sense signal is based on an output of a dimmer. The method also includes, for each of multiple sampling periods, (i) identifying a pulse duty cycle by sampling at least one pulse in the sense signal and calculating a duty cycle of the at least one pulse and (ii) generating an output value identifying a duty cycle for driving one or more LEDs. The output value is based on the pulse duty cycle. The method further includes generating a holding current for the dimmer (i) during the sampling of the at least one pulse in at least one of the sampling periods and (ii) when the pulse duty cycle is less than a specified threshold. The holding current can be applied continuously when the pulse duty cycle is less than the specified threshold (such as 15%).

Abstract: A method includes receiving a sense signal having multiple pulses, where the sense signal is based on an output of a dimmer. The method also includes, for each of multiple sampling periods, (i) identifying at least one pulse duty cycle for at least one pulse in the sense signal during that sampling period and (ii) generating an output value identifying a duty cycle for driving one or more light emitting diodes (LEDs). The output value is based on the at least one pulse duty cycle. The method further includes filtering the output values using a filter and adjusting the filter based on a rate at which the output of the dimmer changes. The filter could be adjusted by controlling whether an additional resistor forms part of an RC filter based on a sampling state.

Abstract: A method includes receiving a sense signal having multiple pulses, where the sense signal is based on an output of a dimmer. The method also includes, for each of multiple sampling periods, sampling a subset of the pulses in the sense signal during that sampling period. The method further includes generating a holding current for the dimmer during the sampling of the subset of pulses in at least one of the sampling periods. In addition, the method includes, for each of the sampling periods, generating an output value identifying a duty cycle for driving one or more light emitting diodes (LEDs). The subset of pulses in each of the sampling periods includes multiple pulses during that sampling period but not one or more initial pulses at a beginning of that sampling period.

Abstract: A method includes receiving a sense signal having multiple pulses, where the sense signal is based on an output of a dimmer. The method also includes, for each of multiple sampling periods, sampling a subset of the pulses in the sense signal during that sampling period. The method further includes generating a holding current for the dimmer during the sampling of the subset of pulses in at least one of the sampling periods. In addition, the method includes, for each of the sampling periods, generating an output value identifying a duty cycle for driving one or more light emitting diodes (LEDs). The subset of pulses in each of the sampling periods includes multiple pulses during that sampling period but not one or more initial pulses at a beginning of that sampling period.

Abstract: A method includes receiving a sense signal having multiple pulses, where the sense signal is based on an output of a dimmer. The method also includes, for each of multiple sampling periods, (i) identifying a pulse duty cycle by sampling at least one pulse in the sense signal and calculating a duty cycle of the at least one pulse and (ii) generating an output value identifying a duty cycle for driving one or more LEDs. The output value is based on the pulse duty cycle. The method further includes generating a holding current for the dimmer (i) during the sampling of the at least one pulse in at least one of the sampling periods and (ii) when the pulse duty cycle is less than a specified threshold. The holding current can be applied continuously when the pulse duty cycle is less than the specified threshold (such as 15%).

Abstract: A method includes receiving a sense signal having multiple pulses, where the sense signal is based on an output of a dimmer. The method also includes, for each of multiple sampling periods, (i) identifying at least one pulse duty cycle for at least one pulse in the sense signal during that sampling period and (ii) generating an output value identifying a duty cycle for driving one or more light emitting diodes (LEDs). The output value is based on the at least one pulse duty cycle. The method further includes filtering the output values using a filter and adjusting the filter based on a rate at which the output of the dimmer changes. The filter could be adjusted by controlling whether an additional resistor forms part of an RC filter based on a sampling state.

Abstract: A semiconductor device (10) includes a protection circuit (12) that has an input (24) for activating the protection circuit in response to a sampling pulse (VENABLE) to detect a fault condition of the semiconductor device, and an output (30) for producing a control signal (VCONTROL1) when a fault condition is detected.

Abstract: A semiconductor device (10) includes a protection circuit (12) that has an input (24) for activating the protection circuit in response to a sampling pulse (VENABLE) to detect a fault condition of the semiconductor device, and an output (30) for producing a control signal (VCONTROL1) when a fault condition is detected.

Abstract: An integrated power factor control circuit (12) for keeping an average AC line current sinusoidal and in phase with the line voltage. The integrated power factor control circuit (12) provides a boosted DC voltage greater than the amplitude of the line voltage. A transconductance amplifier (16) provides a boosted source and sink current when an output voltage is significantly out of regulation. The boosted source and sink current of the transconductance amplifier (16) increases the speed in which the voltage control loop can react to an output voltage change and reduces the time needed to generate the regulated voltage under startup. A comparator (17) provides a boost current at start up and senses a no-load condition during normal operation. The comparator (17) senses the no-load condition and stops switching to eliminate further output charging before an out of range condition occurs.

Abstract: A switching regulator controls the pulse width to a gate of a switching power transistor to maintain an average output voltage. An error amplifier in the regulation loop detects the difference between the actual output voltage and its desired value and maintains the proper regulation voltage at a loop node to control the pulse width to the gate of the power transistor. A quick-start circuit establishes a minimum loop regulation voltage at the loop node during power up allowing the error amplifier to begin regulating immediately thereby reducing start-up delay. The quick-start circuit is disabled after the loop node reaches the minimum loop regulation voltage. The switching regulator also monitors the output voltage by the same input pin to detect an overvoltage condition and shuts down the power switching transistor accordingly.