A dimmable ballast circuit for a compact fluorescent lamp controls the intensity of a lamp tube in response to a phase-control voltage received from a dimmer switch. The ballast circuit comprises a phase-control-to-DC converter circuit that receives the phase-control voltage, which is characterized by a duty cycle defining a target intensity of the lamp tube, and generates a DC voltage representative of the duty cycle of the phase-control voltage. Changes in the duty cycle of the phase-control voltage that are below a threshold amount are filtered out by the converter circuit, while intentional changes in the duty cycle of the phase-control voltage are reflected in changes in the target intensity level and thereby the intensity level of the lamp tube.

A multiple location load control system comprises a main device and remote devices, which do not require neutral connections, but allow for visual and audible feedback at the main device and the remote devices. The main device and the remote devices are adapted to be coupled together via an accessory wiring. The main device can be wired on the line side and the load side of the load control system. The main device is configured to enable a charging path to allow the remote devices to charge power supplies through the accessory wiring during a first time period of a half cycle of the AC power source. The main device and the remote devices are configured to communicate with each other via the accessory wiring during a second time period of the half cycle, for example, by actively pulling-up and actively pulling-down the accessory wiring to communicate using tri-state logic.

A multiple location load control system comprises a main device and remote devices, which do not require neutral connections, but allow for visual and audible feedback at the main device and the remote devices. The main device and the remote devices are adapted to be coupled together via an accessory wiring. The main device can be wired on the line side and the load side of the load control system. The main device is configured to enable a charging path to allow the remote devices to charge power supplies through the accessory wiring during a first time period of a half cycle of the AC power source. The main device and the remote devices are configured to communicate with each other via the accessory wiring during a second time period of the half cycle, for example, by actively pulling-up and actively pulling-down the accessory wiring to communicate using tri-state logic.

A multi-stage driver system includes a switched mode power circuit for providing power to different electrical load(s). Multi-stage driver system includes a control block including at least one microcontroller coupled to control operations of the switched mode power circuit. Switched mode power circuit includes a high voltage region, a low voltage region, and an isolation barrier. High voltage region of the switched mode power circuit includes a switched rectifier and a switched bridge circuit configured to produce a high voltage bidirectional pulse train signal for output to an isolation barrier. Low voltage region of the switched mode power circuit includes a rectification circuit coupled to the isolation barrier and at least one switched converter circuit coupled to the rectification circuit. Control block receives real-time input signals (e.g., analog voltage reading(s)) from the high and low voltage regions and responsively produces control signals to the high and low voltage regions.

A system for use in generating a power signal includes a first stage circuit having: a first input line coupled to a first stage first parallel line having a first stage first switch positioned thereon, a second input line coupled to a first stage second parallel line having a first stage second switch positioned thereon, and a first stage third parallel line oriented in parallel with the first stage first parallel line and the first stage second parallel line between a positive rail and a negative rail, the first stage third parallel line having a first capacitor positioned thereon. The system further includes a second stage circuit having a resonant inverter coupled between the positive rail and the negative rail and configured to output the power signal.

This application discloses an electronic device (e.g., a camera) that a plurality of light sources and a light source driver. The light sources are configurable to a plurality of light source subsets to illuminate a field of view. At least two of the light source subsets include distinct light source members and are configured to illuminate different regions of the field of view. The light source driver is coupled to the plurality of light sources and configured to drive the plurality of light source subsets. In some embodiments, the electronic device includes or is coupled to a camera module configured to capture visual data of the field of view, and the plurality of light sources is configured to provide illumination for the camera module.

This application discloses an electronic device (e.g., a camera) that a plurality of light sources and a light source driver. The light sources are configurable to a plurality of light source subsets to illuminate a field of view. At least two of the light source subsets include distinct light source members and are configured to illuminate different regions of the field of view. The light source driver is coupled to the plurality of light sources and configured to drive the plurality of light source subsets. In some embodiments, the electronic device includes or is coupled to a camera module configured to capture visual data of the field of view, and the plurality of light sources is configured to provide illumination for the camera module.

The invention relates to a method (100) for operating an isolated primary side switched converter (300) for providing a voltage supply to an LED load (401), wherein the converter comprises a galvanic isolation stage (301), the method comprising the steps of: detecting (101) a feedback signal at a primary side of the galvanic isolation stage (301), wherein the feedback signal corresponds to a secondary side voltage, determining (103) an LED supply voltage based on the feedback signal, calculating (105) a threshold value based on a constant reference voltage and an adjustment factor, wherein the adjustment factor is a dynamic factor whose absolute value increases with increasing LED current, and interrupting (107) the voltage supply to the LED load (401) if the determined LED supply voltage exceeds the threshold value.

A dimmable ballast circuit for a compact fluorescent lamp controls the intensity of a lamp tube in response to a phase-control voltage received from a dimmer switch. The ballast circuit comprises a phase-control-to-DC converter circuit that receives the phase-control voltage, which is characterized by a duty cycle defining a target intensity of the lamp tube, and generates a DC voltage representative of the duty cycle of the phase-control voltage. Changes in the duty cycle of the phase-control voltage that are below a threshold amount are filtered out by the converter circuit, while intentional changes in the duty cycle of the phase-control voltage are reflected in changes in the target intensity level and thereby the intensity level of the lamp tube.

A dimmable ballast circuit for a compact fluorescent lamp controls the intensity of a lamp tube in response to a phase-control voltage received from a dimmer switch. The ballast circuit comprises a phase-control-to-DC converter circuit that receives the phase-control voltage, which is characterized by a duty cycle defining a target intensity of the lamp tube, and generates a DC voltage representative of the duty cycle of the phase-control voltage. Changes in the duty cycle of the phase-control voltage that are below a threshold amount are filtered out by the converter circuit, while intentional changes in the duty cycle of the phase-control voltage are reflected in changes in the target intensity level and thereby the intensity level of the lamp tube.