Abstract: A method for driving a light-emitting diode based upon an AC input voltage includes receiving and full-wave rectifying the AC input voltage to generate a full-wave rectified input voltage, generating a pulse width modulation signal according to the full-wave rectified input voltage and a luminance signal, and generating a driving voltage according to the pulse width modulation signal and the full-wave rectified input voltage, and applying the driving voltage to the light-emitting diode.

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.

Abstract: A method for driving a light-emitting diode based upon an AC input voltage includes receiving and full-wave rectifying the AC input voltage to generate a full-wave rectified input voltage, generating a pulse width modulation signal according to the full-wave rectified input voltage and a luminance signal, and generating a driving voltage according to the pulse width modulation signal and the full-wave rectified input voltage, and applying the driving voltage to the light-emitting diode.

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.

Abstract: A current generator, including a chopper stabilization operational amplifier, a transistor, and an impedance unit is provided. The chopper stabilization operational amplifier includes a first input terminal, a second input terminal, and an output terminal. The transistor includes a gate coupled to the output terminal of the chopper stabilization operational amplifier, a first source/drain coupled to the first input terminal of the chopper stabilization operational amplifier, and a second source/drain serving as a current output terminal of the current generator. The impedance unit includes a first terminal coupled to the first source/drain of the transistor, and a second terminal coupled to a first voltage.

Abstract: A generator for generating reference voltage and reference current includes a reference voltage generating circuit for generating a first voltage and a second voltage, which are in combination to produce a reference voltage. The first voltage and the second voltage are respectively having a first-direction response variation and a second-direction response variation, according to a temperature variation. A voltage-to-current inverting circuit is coupled to the reference voltage generating circuit for generating a first current, which has the first-direction response variation as the temperature variation, according to the first voltage. An adding circuit is coupled to the reference voltage generating circuit and the voltage-to-current inverting circuit to obtain a second current corresponding to the second voltage from the reference voltage generating circuit. The first current and the second current are added to have a reference current.

Abstract: A current generator, including a chopper stabilization operational amplifier, a transistor, and an impedance unit is provided. The chopper stabilization operational amplifier includes a first input terminal, a second input terminal, and an output terminal. The transistor includes a gate coupled to the output terminal of the chopper stabilization operational amplifier, a first source/drain coupled to the first input terminal of the chopper stabilization operational amplifier, and a second source/drain serving as a current output terminal of the current generator. The impedance unit includes a first terminal coupled to the first source/drain of the transistor, and a second terminal coupled to a first voltage.