LED Controller with Phase-Shift Dimming Function and LED Phase-Shift Dimming Circuit and Method Thereof
AssigneeRichtek Technology Corporation, R.O.C.
InventorJing-Meng Liu
Life of this patent
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Abstract
The present invention discloses an LED controller with phase-shift dimming function and an LED Phase-Shift dimming circuit and method thereof. The LED controller includes: a power circuit for supplying DC power to multiple LED channels; and an LED phase-shift dimming circuit for receiving a pulse width modulation (PWM) input signal and generating multiple phase-shifted PWM signals with a shifted phase between one another, wherein a turn-ON timing of each of the multiple phase-shifted PWM signals follows a turn-OFF timing of a previous PWM signal which is the input PWM signal or a previous one of the multiple phase-shifted PWM signals.
Claims23
An LED controller with phase-shift dimming function, comprising:
- a power circuit for supplying DC power to multiple LED channels;
- and
- an LED phase-shift dimming circuit for receiving an input pulse width modulation (PWM) signal and generating multiple phase-shifted PWM signals with a shifted phase between one another, wherein a turn-ON timing of each of the multiple phase-shifted PWM signals follows a turn-OFF timing of a previous PWM signal which is the input PWM signal or a previous one of the multiple phase-shifted PWM signals.
An LED phase-shift dimming circuit for receiving an input pulse width modulation (PWM) signal and outputting multiple phase-shifted PWM signals with a shifted phase between one another, the LED phase-shift dimming circuit comprising multiple delay locked loops (DLLs) coupled in series, wherein each DLL calculates a pulse width of a received PWM signal by a high frequency clock signal and generates the phase-shifted PWM signal with the same pulse width as the received PWM signal, wherein a turn-ON timing of each of the multiple phase-shifted PWM signals follows a turn-OFF timing of a previous PWM signal which is the input PWM signal or a previous one of the multiple phase-shifted PWM signals.
An LED phase-shift dimming circuit for receiving an input pulse width modulation (PWM) signal and outputting multiple phase-shifted PWM signals with a shifted phase between one another, the LED phase-shift dimming circuit comprising multiple pulse width mirrors coupled in series, wherein each pulse width mirror includes:
- an edge detector for detecting a rising and/or a falling edge of a PWM signal received by the pulse width mirror;
- a pulse width memory circuit for memorizing a pulse width of the received PWM signal;
- and
- a pulse width generator for generating the phase-shifted PWM signal with the same pulse width as the received PWM signal.
An LED phase-shift dimming circuit for receiving an input pulse width modulation (PWM) signal and outputting multiple phase-shifted PWM signals with a shifted phase between one another, the LED phase-shift dimming circuit comprising multiple pulse width mirrors coupled in series, wherein each pulse width mirror includes:
- an edge detector for detecting a rising and/or a falling edge of a PWM signal received by the pulse width mirror;
- a duty-to-ramp circuit for generating a ramp signal according to a duty of the received PWM signal;
- and
- a pulse width generator for generating the phase-shifted PWM signal with the same pulse width as the received PWM signal.
An LED phase-shift dimming control method for controlling multiple LED channels, comprising:
- receiving an input pulse width modulation (PWM) signal;
- and
- duplicating and converting the input PWM signal to multiple phase-shifted PWM signals with a shifted phase between one another for corresponding LED channels respectively, wherein a turn-ON timing of each of the multiple phase-shifted PWM signals follows a turn-OFF timing of a previous PWM signal which is the input PWM signal or a previous one of the multiple phase-shifted PWM signals.
Dependencies are inferred from the claim text.