Abstract: A dimmer interface circuit includes a buffer stage circuit and a PWM control circuit. The buffer stage circuit converts a dimming input signal to a dimming buffer signal. The buffer stage circuit includes: a power rail generation circuit, which generates a power rail according to the dimming input signal adaptively, so that the dimming input signal is between a high level voltage and a low level voltage of the power rail; and an amplification circuit, which receives the dimming input signal, to generate the dimming buffer signal. The power rail supplies electrical power to the amplification circuit, wherein the amplification circuit operates within a range between the high level voltage and the low level voltage. The PWM control circuit converts the dimming buffer signal to a PWM dimming signal, so as to adjust a brightness of an LED module.

Abstract: A dimmer interface circuit includes a buffer stage circuit and a PWM control circuit. The buffer stage circuit converts a dimming input signal to a dimming buffer signal. The buffer stage circuit includes: a power rail generation circuit, which generates a power rail according to the dimming input signal adaptively, so that the dimming input signal is between a high level voltage and a low level voltage of the power rail; and an amplification circuit, which receives the dimming input signal, to generate the dimming buffer signal. The power rail supplies electrical power to the amplification circuit, wherein the amplification circuit operates within a range between the high level voltage and the low level voltage. The PWM control circuit converts the dimming buffer signal to a PWM dimming signal, so as to adjust a brightness of an LED module.

Abstract: An output stage circuit for transmitting data via a bus includes a high side switch, a high side diode structure, a high side clamp circuit, a low side switch, and a low side diode structure. An impedance circuit of the bus is coupled between the high side switch and the low side switch, for generating a differential output signal according to high and low side output signals. A high side N-type region of the high side diode structure encompasses a high side P-type region thereof, and a low side N-type region of the low side diode structure encompasses a low side P-type region thereof. The high side clamp circuit is connected to the high side N-type region in series, for clamping a voltage of the high side N-type region to be not lower than a predetermined voltage, to prevent a parasitic PNP bipolar junction transistor from being turned ON.

Abstract: AN LED driving apparatus includes a power stage circuit and a dimming control circuit. The power stage circuit drives an LED circuit. The dimming control circuit includes a duty ratio conversion circuit, a digital-to analog conversion (DAC) circuit, an error amplifier (EA) circuit and a modulation control circuit. The duty ratio conversion circuit converts a PWM dimming signal to a digital duty ratio signal. The DAC circuit converts the digital duty ratio signal to an analog reference signal. The EA circuit generates an error amplified signal according to a difference between the analog reference signal and an output current related signal. The modulation control circuit generates a PWM control signal according to the error amplified signal, to control the power switch, such that the output current relates to a dimming duty ratio, whereby the dimming control circuit dims the LED circuit according to the PWM dimming signal.

Abstract: AN LED driving apparatus includes a power stage circuit and a dimming control circuit. The power stage circuit drives an LED circuit. The dimming control circuit includes a duty ratio conversion circuit, a digital-to analog conversion (DAC) circuit, an error amplifier (EA) circuit and a modulation control circuit. The duty ratio conversion circuit converts a PWM dimming signal to a digital duty ratio signal. The DAC circuit converts the digital duty ratio signal to an analog reference signal. The EA circuit generates an error amplified signal according to a difference between the analog reference signal and an output current related signal. The modulation control circuit generates a PWM control signal according to the error amplified signal, to control the power switch, such that the output current relates to a dimming duty ratio, whereby the dimming control circuit dims the LED circuit according to the PWM dimming signal.

Abstract: An output stage circuit for transmitting data via a bus includes a high side switch, a high side diode structure, a high side clamp circuit, a low side switch, and a low side diode structure. An impedance circuit of the bus is coupled between the high side switch and the low side switch, for generating a differential output signal according to high and low side output signals. A high side N-type region of the high side diode structure encompasses a high side P-type region thereof, and a low side N-type region of the low side diode structure encompasses a low side P-type region thereof. The high side clamp circuit is connected to the high side N-type region in series, for clamping a voltage of the high side N-type region to be not lower than a predetermined voltage, to prevent a parasitic PNP bipolar junction transistor from being turned ON.

Abstract: The present invention provides a light emitting device driver circuit and a control circuit and a control method thereof. The light emitting device driver circuit includes a power stage circuit, a feedback circuit, and a control circuit. The control circuit includes a comparison circuit, a hysteresis control circuit, and a bleeder circuit. The control circuit generates an analog control signal according to a rectified dimmer signal and an output signal, for controlling the power stage circuit to regulate an output current, which is supplied to a light emitting device circuit to determine its brightness. When the analog control signal decreases to a predetermined hysteresis low level, the light emitting device driver circuit operates in a cut-off mode wherein the bleeder circuit consumes a bleeder current so as to maintain the output current at a zero current, for keeping the light emitting device circuit OFF.

Abstract: The present invention provides a light emitting device driver circuit and a control circuit and a control method thereof. The light emitting device driver circuit includes a power stage circuit, a feedback circuit, and a control circuit. The control circuit includes a comparison circuit, a hysteresis control circuit, and a bleeder circuit. The control circuit generates an analog control signal according to a rectified dimmer signal and an output signal, for controlling the power stage circuit to regulate an output current, which is supplied to a light emitting device circuit to determine its brightness. When the analog control signal decreases to a predetermined hysteresis low level, the light emitting device driver circuit operates in a cut-off mode wherein the bleeder circuit consumes a bleeder current so as to maintain the output current at a zero current, for keeping the light emitting device circuit OFF.

Abstract: A power converter circuit of a low power illumination device includes a boost converter circuit, a buck converter circuit, and a control circuit, for cooperating with a dimmer and an electric transformer. The control circuit configures the boost converter circuit to alternatively operate in a current conducting mode and an off mode, to draw current from the electric transformer in the current conducting mode, and to stop drawing current from the electric transformer in the off mode. The control circuit further configures the buck converter circuit to generate the required output signals to the low power illumination device according to the configuration of the dimmer so that the low power illumination device may perform the required dimming function.

Abstract: A power converter circuit for a low power illumination device includes a boost converter circuit, a buck converter circuit, and a control circuit. The control circuit configures the boost converter circuit to alternately operate in a current conducting mode and an off mode, to draw different values of the current from an electric transformer in different periods in the current conducting mode, and to stop drawing current from the electric transformer in the off mode. The control circuit further configures the buck converter circuit to generate the required output signals to the low power illumination device according to the output of the boost converter circuit so that the low power illumination device may function normally.

Abstract: The present invention discloses a light emitting device control circuit with dimming function and a control method thereof. The light emitting device control circuit includes: a dimmer circuit, a rectifier and filter circuit, a power converter circuit, and a headroom voltage regulation circuit. The dimmer circuit generates an AC dimming voltage according to an AC voltage. The rectifier and filter circuit generates an input voltage according to the AC dimming voltage. The power converter circuit operates according to a control signal to convert the input voltage to an output voltage which is supplied to a light emitting device circuit. The headroom voltage regulation circuit generates the control signal according to a reference value and a difference between the input voltage and the output voltage, and regulates the difference at a level corresponding to the reference value by a feedback control loop.

Abstract: A power-factor-improving circuit and method for an offline converter block the DC component and obtain the AC component of an input voltage of the offline converter. The AC component is superpositioned onto a DC bias signal to generate a dimming signal for the offline converter to adjust an output current of the offline converter. The offline converter has a high power factor due to the dimming signal with the AC component of the input voltage. In addition, the average of the dimming signal is determined by the DC bias signal, hence the output current can be precisely controlled according to the DC bias signal.

Abstract: The present invention discloses a switching regulator and a control circuit and a control method thereof. The switching regulator generates a compensation signal according to a feedback signal, and generates a driving signal according to the compensation signal, to control a power stage for converting an input voltage to an output voltage. The compensation signal is adjusted according to the input voltage, such that when the input voltage is equal to or lower than a predetermined level, the compensation signal is kept at a predetermined value.

Abstract: The present invention discloses a light emitting device control circuit with dimming function and a control method thereof. The light emitting device control circuit includes: a dimmer circuit, a rectifier and filter circuit, a power converter circuit, and a headroom voltage regulation circuit. The dimmer circuit generates an AC dimming voltage according to an AC voltage. The rectifier and filter circuit generates an input voltage according to the AC dimming voltage. The power converter circuit operates according to a control signal to convert the input voltage to an output voltage which is supplied to a light emitting device circuit. The headroom voltage regulation circuit generates the control signal according to a reference value and a difference between the input voltage and the output voltage, and regulates the difference at a level corresponding to the reference value by a feedback control loop.

Abstract: The present invention discloses a control circuit and a control method of a light emitting device circuit. When the light emitting device circuit is normally connected in normal operation, an output current is regulated to a predetermined current. When the light emitting device circuit is removed, an output voltage is regulated to a predetermined voltage. When the light emitting device circuit is reconnected, the output current is regulated to the predetermined current. The output voltage is at or above a level when the light emitting device circuit is normally connected in normal operation, and the predetermined voltage is lower than this level.

Abstract: The present invention discloses an active bleeder circuit capable of triggering a tri-electrode AC switch (TRIAC) circuit in all phase. The active bleeder circuit receives a rectified signal having an OFF phase and an ON phase. The active bleeder includes: a detection circuit for generating a detection signal according to the rectified signal and accumulating the detection signal in the OFF phase of the rectified signal; and a current sinker circuit coupled to the detection circuit, for generates a latching current to trigger the TRIAC circuit by operating a switch when the detection signal exceeds a predetermined level. The present invention also discloses a light emitting device power supply circuit and a TRIAC control method using the active bleeder circuit.

Abstract: The present invention discloses a light emitting device driver circuit and a control circuit and a control method thereof. The light emitting device driver circuit converts an input voltage to an output voltage, and provides an output current to a light emitting device circuit. The present invention detects whether the output voltage exceeds a predetermined level, and if no, the regulation target of the output current is set to a relatively higher current to fast charge an output capacitor; if yes, the output current is regulated to a desired target, wherein the relatively higher current is higher than the desired target.

Abstract: A control circuit of a switching regulator, which controls rectified power within a predetermined range, detects an input voltage and an input current to generate a voltage detection signal and a current detection signal respectively, and the voltage detection signal and the current detection signal are multiplied by one the other to generate a power index. The control circuit generates an error signal according to the power index and a reference signal. A low-pass-filter filters a high frequency band in the process. A control signal generation circuit of the control circuit generates a control signal according to the error signal. And a driver circuit of the control circuit generates an operation signal according to the control signal, for switching a power switch to convert the rectified power to an output voltage.

Abstract: A power converter circuit for a low power illumination device includes a boost converter circuit, a buck converter circuit, and a control circuit. The control circuit configures the boost converter circuit to alternately operate in a current conducting mode and an off mode, to draw different values of the current from an electric transformer in different periods in the current conducting mode, and to stop drawing current from the electric transformer in the off mode. The control circuit further configures the buck converter circuit to generate the required output signals to the low power illumination device according to the output of the boost converter circuit so that the low power illumination device may function normally.

Abstract: A power converter circuit of a low power illumination device includes a boost converter circuit, a buck converter circuit, and a control circuit, for cooperating with a dimmer and an electric transformer. The control circuit configures the boost converter circuit to alternatively operate in a current conducting mode and an off mode, to draw current from the electric transformer in the current conducting mode, and to stop drawing current from the electric transformer in the off mode. The control circuit further configures the buck converter circuit to generate the required output signals to the low power illumination device according to the configuration of the dimmer so that the low power illumination device may perform the required dimming function.