Abstract: Light output from an LED light source is increased or reduced in response to adjustment of a triac-based dimmer having a triac holding current to maintain conduction of the dimmer. An LED controller to control the light output includes a voltage-controlled impedance to provide an adaptive holding current that causes a triac current of the dimmer to be greater than the triac holding current, particularly when the dimmer is adjusted for significantly low light output (e.g., less than 5%, 2%, or 1% of full power light output). The adaptive holding current also allows for smooth increase of the light output starting from low light output, without perceivable flicker or shimmer. In one example, the voltage-controlled impedance is a resistive-like impedance that is placed on a secondary side of a transformer providing power to the LED light source. In another example, the voltage-controlled impedance is not pulse width modulated.

Abstract: Light output from an LED light source is increased or reduced in response to adjustment of a triac-based dimmer having a triac holding current to maintain conduction of the dimmer. An LED controller to control the light output includes a voltage-controlled impedance to provide an adaptive holding current that causes a triac current of the dimmer to be greater than the triac holding current, particularly when the dimmer is adjusted for significantly low light output (e.g., less than 5%, 2%, or 1% of full power light output). The adaptive holding current also allows for smooth increase of the light output starting from low light output, without perceivable flicker or shimmer. In one example, the voltage-controlled impedance is a resistive-like impedance that is placed on a secondary side of a transformer providing power to the LED light source. In another example, the voltage-controlled impedance is not pulse width modulated.

Abstract: Light output from an LED light source is increased or reduced in response to adjustment of a triac-based dimmer having a triac holding current to maintain conduction of the dimmer. An LED controller to control the light output includes a voltage-controlled impedance to provide an adaptive holding current that causes a triac current of the dimmer to be greater than the triac holding current, particularly when the dimmer is adjusted for significantly low light output (e.g., less than 5%, 2%, or 1% of full power light output). The adaptive holding current also allows for smooth increase of the light output starting from low light output, without perceivable flicker or shimmer. In one example, the voltage-controlled impedance is a resistive-like impedance that is placed on a secondary side of a transformer providing power to the LED light source. In another example, the voltage-controlled impedance is not pulse width modulated.

Abstract: Light output from an LED light source is increased or reduced in response to adjustment of a triac-based dimmer having a triac holding current to maintain conduction of the dimmer. An LED controller to control the light output includes a voltage-controlled impedance to provide an adaptive holding current that causes a triac current of the dimmer to be greater than the triac holding current, particularly when the dimmer is adjusted for significantly low light output (e.g., less than 5%, 2%, or 1% of full power light output). The adaptive holding current also allows for smooth increase of the light output starting from low light output, without perceivable flicker or shimmer. In one example, the voltage-controlled impedance is a resistive-like impedance that is placed on a secondary side of a transformer providing power to the LED light source. In another example, the voltage-controlled impedance is not pulse width modulated.

Abstract: An adaptive power regulation converter for battery powered emergency lighting LED driver is disclosed. The power feedback and power compensation circuits regulate the output power to LED strings and provides tighten regulated constant power and constant lumens for emergency light during power out time. The adaptive power regulation converter can be used for a great range of LED strings.

Abstract: An adaptive power regulation converter for battery powered emergency lighting LED driver is disclosed. The power feedback and power compensation circuits regulate the output power to LED strings and provides tighten regulated constant power and constant lumens for emergency light during power out time. The adaptive power regulation converter can be used for a great range of LED strings.

Abstract: An adaptive power regulation converter for battery powered emergency lighting LED driver is disclosed. The power feedback and power compensation circuits regulate the output power to LED strings and provides tighten regulated constant power and constant lumens for emergency light during power out time. The adaptive power regulation converter can be used for a great range of LED strings.

Abstract: An adaptive power regulation converter for battery powered emergency lighting LED driver is disclosed. The power feedback and power compensation circuits regulate the output power to LED strings and provides tighten regulated constant power and constant lumens for emergency light during power out time. The adaptive power regulation converter can be used for a great range of LED strings.

Abstract: Resistance in parallel with inductors in a series leg of the low-pass filter facilitates changing input and output resistance of the filter with little or no change in the reactance of the inductors. Furthermore, the reactance of the capacitors in the shunt legs of the filter will be substantially unaffected. This assists the designer in matching the impedance of the filter in the pass-band while still providing substantial impedance mismatching in the stop-band without substantially affecting the characteristics of the filter. Facilitating impedance matching in the pass-band and impedance mismatching in the stop-band is accomplished without the need for more complex active components. POTS splitters making use of such filters can facilitate impedance matching of line and load termination in a telecommunications system in response to signals within the frequencies of typical analog telephony service while providing impedance mismatching in response to signals within the frequencies of typical xDSL service.

Abstract: Cascade low-pass filters are useful in attenuating the xDSL band in a POTS splitter. The design of the low-pass filter is a sixth-order filter having two stages. A first stage includes a fourth-order filter, preferably with a stop-band frequency of approximately 48 kHz. A second stage includes a second-order filter in cascade with the fourth-order filter. For this filter, the stop-band frequency is preferably approximately 29 kHz. The inductance value of the second stage is relatively small in comparison to the inductance values of the first stage. In this manner, improvements in xDSL band attenuation are facilitated with little or no eroding of the voice band performance such as insertion loss, pass-band attenuation and return loss.

Abstract: Circuits for testing POTS service on a shared POTS/xDSL carrier include microfilters for selective coupling to the subscriber loop side of an xDSL filter associated with a subscriber line interface circuit. Such configurations facilitate testing of the POTS service using an insertion point that is between the xDSL filter and the subscriber loop in a manner that is transparent to subscribers.

Abstract: Circuits for testing POTS service on a shared POTS/xDSL carrier include microfilters for selective coupling to the subscriber loop side of an xDSL filter associated with a subscriber line interface circuit. Such configurations facilitate testing of the POTS service using an insertion point that is between the xDSL filter and the subscriber loop in a manner that is transparent to subscribers.

Abstract: Cascade low-pass filters are useful in attenuating the xDSL band in a POTS splitter. The design of the low-pass filter is a sixth-order filter having two stages. A first stage includes a fourth-order filter, preferably with a stop-band frequency of approximately 48 kHz. A second stage includes a second-order filter in cascade with the fourth-order filter. For this filter, the stop-band frequency is preferably approximately 29 kHz. The inductance value of the second stage is relatively small in comparison to the inductance values of the first stage. In this manner, improvements in xDSL band attenuation are facilitated with little or no eroding of the voice band performance such as insertion loss, pass-band attenuation and return loss.

Abstract: Resistance in parallel with inductors in a series leg of the low-pass filter facilitates changing input and output resistance of the filter with little or no change in the reactance of the inductors. Furthermore, the reactance of the capacitors in the shunt legs of the filter will be substantially unaffected. This assists the designer in matching the impedance of the filter in the pass-band while still providing substantial impedance mismatching in the stop-band without substantially affecting the characteristics of the filter. Facilitating impedance matching in the pass-band and impedance mismatching in the stop-band is accomplished without the need for more complex active components. POTS splitters making use of such filters can facilitate impedance matching of line and load termination in a telecommunications system in response to signals within the frequencies of typical analog telephony service while providing impedance mismatching in response to signals within the frequencies of typical xDSL service.