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US 2010/0141173 A1Published application
Linearity in led dimmer control
AssigneeLinear Technology Corporation
InventorMichael George Negrete
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AssigneeLinear Technology Corporation
InventorMichael George Negrete
Estimating the term…
A flyback controller may generate a switching signal for controlling the delivery of input current into a primary winding of a transformer in a flyback converter that has a secondary winding in the transformer and that is driven by AC output from a dimmer control that is chopped at a phase angle based on a setting of the dimmer control. The flyback controller may include a tracking input configured to receive a dimmer output tracking signal that is representative of the instantaneous magnitude of the output from the dimmer control. The flyback controller may include an averaging circuit configured to average the dimmer output tracking signal so as to generate an average dimmer output signal that is representative of a time-averaged value of the dimmer output tracking signal. The flyback controller may be configured to cause the average output current in the secondary winding of the transformer to vary as a function of the average dimmer output signal when the phase angle exceeds a threshold. The flyback controller may be configured to generate the switching signal with a duty cycle that causes the luminance level of light produced by one or more LEDs to vary when the phase angle exceeds a threshold by what appears to the human eye to be a more linear function of the phase angle than if the luminance level actually varied as a linear function of the phase angle.
A flyback controller for generating a switching signal for controlling the delivery of input current into a primary winding of a transformer in a flyback converter that has a secondary winding in the transformer and that is driven by AC output from a dimmer control that is chopped at a phase angle based on a setting of the dimmer control, the flyback controller being configured to:
A flyback controller for generating a switching signal for controlling the delivery of input current into a primary winding of a transformer in a flyback converter that is connected to one or more LEDs and that is driven by AC output from a dimmer control that is chopped at a phase angle based on a setting of the dimmer control, the flyback controller being configured to generate the switching signal with a duty cycle that causes the luminance level of light produced by the one or more LEDs to vary when the phase angle exceeds a threshold by what appears to the human eye to be a more linear function of the phase angle than if the luminance level actually varied as a linear function of the phase angle.
A flyback controller for generating a switching signal for controlling the delivery of input current into a primary winding of a transformer in a flyback converter that is connected to one or more LEDs and that is driven by AC output from a dimmer control that is chopped at a phase angle based on a setting of the dimmer control, the flyback controller comprising:
Dependencies are inferred from the claim text.