A driver for a light-emitting diode (LED) device comprises: a rectifier, a current regulator and a detecting module. The rectifier is coupled to a ballast and configured to convert an alternating current from the ballast into a direct current. The current regulator is coupled between the rectifier and the LED device, and configured to receive the direct current from the rectifier and output a driving current to the LED device. The detecting module is configured to detect a signal indicating an output characteristic of the ballast, during a startup stage of the LED device. The current regulator is configured to convert the direct current from the rectifier into the driving current with a value equal to or less than a preset current threshold when the signal meets a preset condition, and the preset current threshold is less than a maximum current the LED device is able to carry without damage.

A driver for a light-emitting diode (LED) device comprises: a rectifier, a current regulator and a detecting module. The rectifier is coupled to a ballast and configured to convert an alternating current from the ballast into a direct current. The current regulator is coupled between the rectifier and the LED device, and configured to receive the direct current from the rectifier and output a driving current to the LED device. The detecting module is configured to detect a signal indicating an output characteristic of the ballast, during a startup stage of the LED device. The current regulator is configured to convert the direct current from the rectifier into the driving current with a value equal to or less than a preset current threshold when the signal meets a preset condition, and the preset current threshold is less than a maximum current the LED device is able to carry without damage.

This light-emitting element drive control device (100) comprises: a drive logic unit (113) which performs a drive control of a switch output stage (N1, D1, L1) for dropping an input voltage (VIN) to an output voltage (VOUT) and supplying a light-emitting element therewith; a charge-pump power supply unit (a) which generates a step-up voltage (CP) higher than the input voltage (VIN); and a current detecting comparator (114) which receives a supply of the step-up voltage (CP) and the output voltage (VOUT) as power supply voltages, and generates control signals (SET, RST) for the drive logic unit (113) by directly comparing a current detection signal (Vsns) corresponding to an inductor current (IL) of the switch output stage with a peak detection value (Vsns_pk) and a bottom detection value (Vsns_bt).

This light-emitting element drive control device (100) comprises: a drive logic unit (113) which performs a drive control of a switch output stage (N1, D1, L1) for dropping an input voltage (VIN) to an output voltage (VOUT) and supplying a light-emitting element therewith; a charge-pump power supply unit (a) which generates a step-up voltage (CP) higher than the input voltage (VIN); and a current detecting comparator (114) which receives a supply of the step-up voltage (CP) and the output voltage (VOUT) as power supply voltages, and generates control signals (SET, RST) for the drive logic unit (113) by directly comparing a current detection signal (Vsns) corresponding to an inductor current (IL) of the switch output stage with a peak detection value (Vsns_pk) and a bottom detection value (Vsns_bt).

Multiple current sources are coupled in series to corresponding light-emitting elements. Switching converter supplies driving voltage to the multiple light-emitting elements and current sources. Pulse modulator generates pulse signal that transits to on level when the smallest from among voltages across both ends of the multiple current sources falls to bottom limit voltage, and subsequently transits to off level. Frequency stabilization circuit controls pulse modulator such that the frequency of pulse signal approaches its target. Dummy load circuit is configured to lower driving voltage in the enable state, to be set to the enable state when switching transistor continues to be off for a predetermined time, and to be set to the disable state in response to the next turn-on of the switching transistor.

Multiple current sources are coupled in series to corresponding light-emitting elements. Switching converter supplies driving voltage to the multiple light-emitting elements and current sources. Pulse modulator generates pulse signal that transits to on level when the smallest from among voltages across both ends of the multiple current sources falls to bottom limit voltage, and subsequently transits to off level. Frequency stabilization circuit controls pulse modulator such that the frequency of pulse signal approaches its target. Dummy load circuit is configured to lower driving voltage in the enable state, to be set to the enable state when switching transistor continues to be off for a predetermined time, and to be set to the disable state in response to the next turn-on of the switching transistor.

A two-wire lighting control device, may include a controllably conductive device, a signal generation circuit, and a filter circuit. The controllably conductive device may apply an AC line voltage to a load, being conductive for a first duration of time and non-conductive for a second duration of time within a half-cycle of the AC line voltage. The signal generation circuit may generate a non-zero-magnitude signal. And, the filter circuit may receive a signal from the controllably conductive device during the first duration of time and the non-zero-magnitude signal from the signal generation circuit during the second duration of time. The non-zero-magnitude signal may, in effect, fill-in or complement the signal from the controllably conductive device, and any delay variation as a function of the firing angle of the controllably conductive device through the filter circuit may be mitigated by the presence of the non-zero-magnitude signal.

A two-wire lighting control device, may include a controllably conductive device, a signal generation circuit, and a filter circuit. The controllably conductive device may apply an AC line voltage to a load, being conductive for a first duration of time and non-conductive for a second duration of time within a half-cycle of the AC line voltage. The signal generation circuit may generate a non-zero-magnitude signal. And, the filter circuit may receive a signal from the controllably conductive device during the first duration of time and the non-zero-magnitude signal from the signal generation circuit during the second duration of time. The non-zero-magnitude signal may, in effect, fill-in or complement the signal from the controllably conductive device, and any delay variation as a function of the firing angle of the controllably conductive device through the filter circuit may be mitigated by the presence of the non-zero-magnitude signal.

A light source driving method is applied to a light source driving module electrically connected to a light source and a controller. The light source driving module includes a frequency setting module, a driving circuit, and a conversion module. The frequency setting module generates a frequency setting signal according to a switching signal. The driving circuit generates a light source driving signal after receiving the switching signal and a current control signal. The conversion module selectively generates a driving current flowing through the light source in response to the light source driving signal. The driving current increases continuously during a rising duration, and the light source driving signal has a first operating frequency during the rising period. The driving current remains unchanged during a stable duration, and the light source driving signal has a second operating frequency during the stable period.

A light source driving method is applied to a light source driving module electrically connected to a light source and a controller. The light source driving module includes a frequency setting module, a driving circuit, and a conversion module. The frequency setting module generates a frequency setting signal according to a switching signal. The driving circuit generates a light source driving signal after receiving the switching signal and a current control signal. The conversion module selectively generates a driving current flowing through the light source in response to the light source driving signal. The driving current increases continuously during a rising duration, and the light source driving signal has a first operating frequency during the rising period. The driving current remains unchanged during a stable duration, and the light source driving signal has a second operating frequency during the stable period.