Lighting system, electronic device for a lighting system and method for operating the electronic device

摘要

An electronic device for a lighting system, comprising a TRIAC dimmer configured to receive a mains supply voltage and provide a phase cut voltage to the electronic device and having a control loop configured to control a duty cycle of a switched voltage converter that receives the rectified input voltage and provides drive current to a light emitting semiconductor device. The control loop has an error amplifier that is coupled to receive a sense voltage that is indicative of a current through the light emitting semiconductor device, the error amplifier is configured to provide a feedback signal to a pulse width modulation logic configured to control the duty cycle of the switched voltage converter to provide a constant drive current to the light emitting semiconductor device in response to the sense voltage, the error amplifier being coupled to receive a reference voltage that is a function of the input voltage.

主权项

1. An electronic device for a lighting system, wherein the lighting system comprises a TRIAC dimmer and is configured to receive a mains supply voltage and to provide a phase cut voltage to the electronic device, wherein the electronic device comprises:
a control loop that is configured to control a duty cycle of a switched voltage converter that receives a rectified phase cut voltage as an input voltage and provides a drive current to a light emitting semiconductor device, the control loop comprises an error amplifier that is coupled to receive a sense voltage that is indicative to a current through the light emitting semiconductor device, the error amplifier being configured to provide a feedback signal to a pulse width modulation logic that is configured to control the duty cycle of the switched voltage converter so as to provide a constant drive current to the light emitting semiconductor device in response to the sense voltage and the error amplifier being coupled to receive a reference voltage that is a function of the input voltage, wherein a DC path is present between the inverting input of the error amplifier that is coupled to the reference voltage and an output terminal of the error amplifier.