DIMMER CIRCUIT APPLICABLE FOR LED DEVICE AND CONTROL METHOD THEREOF
First Claim
1. A dimmer circuit, comprising:
- a bleeder as a dummy load;
a phase dimmer for generating a signal corresponding to an adjustment of the phase dimmer by a user;
a phase detect circuit for detecting a phase angle of the signal;
a pulse width modulation (PWM) circuit for generating a PWM signal to drive a light emitting diode (LED) device; and
a programmable micro controller, coupled to the phase detect circuit, wherein the programmable micro controller receives the signal and the phase angle to determine pulse width of the PWM signal according to the phase angle and the programmable micro controller generates a control signal to turn on/off the bleeder according to the phase angle.
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Abstract
A dimmer circuit applicable for LED device and control method thereof is disclosed in the embodiments of the present invention. The dimmer circuit is applicable for controlling at least a LED device. The dimmer circuit includes a rectifier, a bleeder, a phase angle detect circuit, a constant current circuit and a programmable micro controller. The phase angle detect circuit couples to the programmable micro controller. The constant current circuit couples to the LED device The programmable micro controller generates a PWM signal according to the output signal of the phase angle detect circuit to adjust current of the constant current circuit.
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Citations
15 Claims
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1. A dimmer circuit, comprising:
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a bleeder as a dummy load; a phase dimmer for generating a signal corresponding to an adjustment of the phase dimmer by a user; a phase detect circuit for detecting a phase angle of the signal; a pulse width modulation (PWM) circuit for generating a PWM signal to drive a light emitting diode (LED) device; and a programmable micro controller, coupled to the phase detect circuit, wherein the programmable micro controller receives the signal and the phase angle to determine pulse width of the PWM signal according to the phase angle and the programmable micro controller generates a control signal to turn on/off the bleeder according to the phase angle. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A programmable micro controller, comprising:
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a phase angle detect circuit, for detecting a phase angle of a signal provided by a phase detect circuit; a phase angle filter for filtering noises of the phase angle; a driver for generating a driving signal according to a command to control a bleeder; a timer for generating a clock synchronous with the driver and the phase angle detect circuit; a dimming curve translator for providing a dimming curve; a pulse width modulation circuit, for generating a PWM signal to control brightness of the LED device; and a control logic for operating in coordination with the clock of the timer, receiving the phase angle, and determining the command to control the driver and the pulse width modulation circuit to generate the pulse width modulation signal, according to the phase angle.
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13. A frequency modulation method for controlling a bleeder:
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providing a tick timer and using a phase angle signal from a phase detect circuit to determine whether or not to increase or decrease tick timer and to compare if overflow occurs; correlating the phase angle to a conversion curve and performing calculation to generate a corresponding pulse width modulation duty cycle to control brightness of a light emitting diode device; and determining whether a current phase angle is larger than a previous phase angle or not, decreasing the tick timer when the current phase angle is larger than the previous phase angle, and increasing the tick timer when the current phase angle is smaller than the previous phase angle; wherein the bleeder is triggered when overflow occurs.
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14. A method for a programmable micro controller to detect a phase angle, the method comprising:
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determining whether an operating clock of phase angle detection is synchronous with a trigger signal of a bleeder or not and acquiring the phase angle when it is synchronous; determining whether a current phase angle is a new phase angle or not and filtering the new phase angle if the current phase angle is a phase angle; and determining whether the received phase angle is changed or not;
if the received phase angle is changed, performs phase angle/brightness conversion according to information related to the changed phase angle and provides the result to generate a corresponding PWM signal to control brightness of a light emitting diode device. - View Dependent Claims (15)
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Specification