Abstract:
An apparatus includes a plurality of series-connected current control circuits configured to control a current therethrough responsive to at least one current reference signal and to be coupled in parallel with a load, such as a string of LEDs. The apparatus further includes a voltage control circuit configured to control respective voltages across respective ones of the current control circuits. In some embodiments, the voltage control circuit may be configured to individually adjust responses of the current control circuits responsive to the voltages across the current control circuits. In further embodiments, the voltage control circuit may include respective voltage limiters coupled across respective ones of the current control circuits.
Abstract:
An LED lighting device comprises at least one LED selectively energizable to develop light and a control circuit coupled to the LED that develops a command signal comprising first and second command signal components for controlling the at least one LED to cause the LED to develop light comprising a desired brightness in response to the first command signal component. The control circuit controls the at least one LED to cause the LED to develop light comprising a further desired parameter magnitude other than desired brightness in response to the second command signal component, and the first signal component comprises an IEC 0-10 volt analog lighting control.
Abstract:
A level shifting circuit can include a level shifting circuit input node that can be coupled to an input signal, where the input signal can be configured to switch between discrete voltage levels in an input voltage domain. A level shifting circuit output node of the level shifting circuit can be configured to provide shifted voltage levels that are shifted relative to the input signal responsive to switching of the input signal. A constant voltage element can have a first terminal that can be coupled to the level shifting circuit input node and can have a second terminal that can be coupled to the level shifting circuit output node. The constant voltage element can be configured to provide a constant voltage level shift to the input signal to provide the shifted voltage levels responsive to switching of the input signal between the discrete voltage levels in the first voltage domain.
Abstract:
A solid state lighting apparatus can include a variable color input signal configured to indicate a target color of light output from the apparatus. A string current Pulse Width Modulation (PWM) controller circuit can be coupled to the variable color input signal, where the string current PWM controller circuit can be configured to generate a plurality of PWM signals having respective variable duty cycles to enable/disable respective particular string currents for respective variable times as the variable color input signal changes.
Abstract:
A power supply includes a power conversion circuit configured to selectively operate in one of an active mode in which output power is supplied to a load and a standby mode in which output power is not supplied to the load, a plurality of auxiliary circuits including a first auxiliary circuit and a second auxiliary circuit, a bias node configured to supply power to the plurality of auxiliary circuits, and a switch that is coupled between the bias node and the first auxiliary circuit and that is configured to disconnect the first auxiliary circuit from the bias node in response to a control signal.
Abstract:
According to one aspect, a control system for an LED luminaire includes a dimming control circuit that develops an analog dimming command signal that is variable between zero volts and ten volts to command LED brightness. The control system further includes a modulation circuit coupled to the dimming control circuit. The modulation circuit modifies the analog dimming command signal so as to include digital data for further commanding a parameter of LED operation.
Abstract:
A power supply includes a power conversion circuit configured to selectively operate in one of an active mode in which output power is supplied to a load and a standby mode in which output power is not supplied to the load, a plurality of auxiliary circuits including a first auxiliary circuit and a second auxiliary circuit, a bias node configured to supply power to the plurality of auxiliary circuits, and a switch that is coupled between the bias node and the first auxiliary circuit and that is configured to disconnect the first auxiliary circuit from the bias node in response to a control signal.
Abstract:
According to one aspect, a load control system responsive to electric power from either a first power source or a second power source operable during first and second time periods, respectively, comprises a first circuit responsive to the first and second power sources to develop power waveforms having different characteristics during the first and second time periods. The load control system further includes a second circuit coupled to the first circuit and responsive to the characteristics of the power developed by the first circuit for developing first and second different outputs during the first and second time periods, respectively.
Abstract:
A method of operating a switched mode power supply circuit can be provided by determining an error in a control signal for the switched mode power supply circuit. The error can be compared to an error threshold value to provide a filtering selection. The error can be adaptively filtered of based on the filtering selection to provide a selected filtering and the error can be filtered using the selected filtering.
Abstract:
An LED lighting device comprises at least one LED selectively energizable to develop light and a control circuit coupled to the LED that develops a command signal comprising first and second command signal components for controlling the at least one LED to cause the LED to develop light comprising a desired brightness in response to the first command signal component. The control circuit controls the at least one LED to cause the LED to develop light comprising a further desired parameter magnitude other than desired brightness in response to the second command signal component, and the first signal component comprises an IEC 0-10 volt analog lighting control.