DIMMER CIRCUIT OF LIGHT EMITTING DIODE AND ISOLATED VOLTAGE GENERATOR AND DIMMER METHOD THEREOF
First Claim
1. An isolated voltage generator adapted to a light-emitting diode (LED) dimmer circuit, the LED dimmer circuit having a triac dimmer, and the isolated voltage generator comprising:
- a rectifier, receiving a first voltage modulated by the triac dimmer;
a controller, having an input terminal, a driving output terminal, a feedback terminal and a current sensing terminal, the controller generating a control signal according to voltages received by the feedback terminal and the current sensing terminal, and outputting the control signal through the driving output terminal;
a transformer, having a first side winding, a second side winding and a third side winding, wherein a first terminal of the first side winding is coupled to the rectifier, a first terminal of the second side winding outputs a driving signal, a second terminal of the second side winding is coupled to a second ground voltage, and the third side winding is coupled between the input terminal of the controller and a first ground voltage;
a switch, having a control terminal, a first terminal and a second terminal, the control terminal of the switch being coupled to the driving output terminal of the controller, the first terminal of the switch being coupled to a second terminal of the first side winding, and the second terminal of the switch being coupled to the current sensing terminal of the controller;
a voltage divider, coupled among a first terminal of the third side winding of the transformer, the feedback terminal of the controller and the first ground voltage, for providing a divided voltage to the feedback terminal of the controller; and
a first resistor, coupled between the current sensing terminal of the controllerand the first ground voltage.
1 Assignment
0 Petitions
Accused Products
Abstract
An isolated configuration dimmer circuit of a light emitting diode (LED) applied to a conventional triac dimmer and a dimmer method are provided. When a dimmer phase angle of the triac dimmer is regulated, a second side winding of a transformer of the isolated configuration produces a pulse width corresponding to a modulated alternating current (AC) voltage, so as to regulate the pulse width of a driving signal output by the second side winding of the transformer. In addition, the dimmer circuit regulates the magnitude of a current flowing through the light emitting diode (LED) according to the pulse width corresponding to the modulated AC voltage. Accordingly, the dimmer circuit regulates the pulse width and the magnitude of the current flowing through the LED according to the dimmer phase angle of the triac dimmer. Therefore, a dimmer range of the LED can be increased.
114 Citations
26 Claims
-
1. An isolated voltage generator adapted to a light-emitting diode (LED) dimmer circuit, the LED dimmer circuit having a triac dimmer, and the isolated voltage generator comprising:
-
a rectifier, receiving a first voltage modulated by the triac dimmer; a controller, having an input terminal, a driving output terminal, a feedback terminal and a current sensing terminal, the controller generating a control signal according to voltages received by the feedback terminal and the current sensing terminal, and outputting the control signal through the driving output terminal; a transformer, having a first side winding, a second side winding and a third side winding, wherein a first terminal of the first side winding is coupled to the rectifier, a first terminal of the second side winding outputs a driving signal, a second terminal of the second side winding is coupled to a second ground voltage, and the third side winding is coupled between the input terminal of the controller and a first ground voltage; a switch, having a control terminal, a first terminal and a second terminal, the control terminal of the switch being coupled to the driving output terminal of the controller, the first terminal of the switch being coupled to a second terminal of the first side winding, and the second terminal of the switch being coupled to the current sensing terminal of the controller; a voltage divider, coupled among a first terminal of the third side winding of the transformer, the feedback terminal of the controller and the first ground voltage, for providing a divided voltage to the feedback terminal of the controller; and a first resistor, coupled between the current sensing terminal of the controller and the first ground voltage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
-
-
9. An LED dimmer circuit, comprising:
-
a triac dimmer, receiving a first voltage, and modulating the first voltage according to a dimmer phase angle; an isolated voltage generator, coupled to the triac dimmer, and generating a driving signal according to the modulated first voltage, so as to drive at least one LED, wherein the first voltage and a voltage forming the driving signal are mutually isolated; and a current controller, controlling a current flowing through the LED according to a regulation signal. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
-
-
24. A dimmer method of an LED, adapted to an LED dimmer circuit, a triac dimmer of the LED dimmer circuit modulating an AC voltage according to a dimmer phase angle, an isolated voltage generator of the LED dimmer circuit generating a driving signal according to the modulated AC voltage, so as to drive at least one LED, and a current controller of the LED dimmer circuit controlling a current flowing through the LED, the dimmer method comprising:
-
increasing a pulse width of the modulated AC voltage when the dimmer phase angle is decreased, and correspondingly increasing a pulse width of the driving signal so as to increase a pulse width of the current flowing through the LED, wherein a voltage forming the modulated AC voltage and a voltage forming the driving signal are mutually isolated; and decreasing the pulse width of the modulated AC voltage when the dimmer phase angle is increased, and correspondingly decreasing the pulse width of the driving signal so as to decrease the pulse width of the current flowing through the LED. - View Dependent Claims (25, 26)
-
Specification