Abstract: A digitally controlled voltage generator is disclosed for use in applications requiring fine resolution voltage control, such as generating a common voltage for a liquid crystal display. A constant resistance digital to analog converter (DAC) is configured to provide appropriate voltage steps by tuning bias resistors to generate desirable reference voltages for the DAC. The bias resistors are configured to be tuned after placement and routing steps in an integrated circuit design.

Abstract: A method includes: detecting one of a short-to-ground condition and a short-to-supply condition at an output node; after a delay, selectively activating a feedback control transistor according to the detecting; detecting a first current passing through a first transistor using a second transistor sized to be smaller than the first transistor; mirroring the detected current using a plurality of transistors to form a feedback current; and providing the feedback current to a gate electrode of the first transistor according to the selectively activating the feedback control transistor.

Abstract: A backlight driver includes current sources that are connected between LED strings and a number of bias voltages. There can be any number of different bias voltages, each at a ground potential or higher voltage. The bias voltage is selected for a particular LED string in order to reduce a current drop across the current source. This reduces the power consumption of the current source and LED string. Heat dissipation is also reduced.

Abstract: An LED lighting device includes a luminescent circuit, a detecting circuit, an adjustable current source and a dimming control circuit. The luminescent circuit is driven by a rectified AC voltage for providing light. The detecting circuit is configured to detect a rising edge or a falling edge of the LED current associated with a frequency of the rectified AC voltage. The dimming current regulator is configured to vary a duty cycle of the LED current according to a PWM signal. The dimming control circuit is configured to generate the PWM signal and synchronize a frequency of the PWM signal with the frequency of the rectified AC voltage at the detected rising edge or the falling edge of the rectified AC voltage.

Abstract: An LED lighting device includes first and second luminescent units, first and second current controllers, a line voltage sensing unit and a mode control unit. The first current controller with a first current setting is selectively coupled to the first luminescent unit according to a sensing voltage associated a range of the rectified AC voltage. The second current controller with a second current setting is coupled in series to the second luminescent unit. The line voltage sensing unit is configured to detect the sensing voltage. The mode control unit is configured to operate the LED lighting device in a first driving mode when detecting that the rectified AC voltage is within a first AC range and operate the LED lighting device in a second driving mode when detecting that the rectified AC voltage is within a second AC range.

Abstract: An LED lighting device includes multiple luminescent devices driven by a rectified AC voltage. The multiple luminescent devices are turned on flexibly in a multi-stage driving scheme using multiple current controllers. The current settings of the two driving stages with the highest current level and the second highest current level are adjusted according to the variation in the rectified AC voltage VAC or according to the variation in the duty cycle of the luminance device due to the variation in the rectified AC voltage. The present invention can improve the line/load regulation of the LED lighting device when the rectified AC voltage somehow fluctuates between its upper bound and lower bound.

Abstract: An LED lighting device includes first through third luminescent devices and first through third current controllers. The first and second luminescent devices are driven by a rectified AC voltage for providing light of a first color. The third luminescent device is driven by the rectified AC voltage for providing light of a second color different from the first color. The first through third current controllers are configured to regulate the current flowing through the first through third current controllers according to a first current setting, a second current setting and a third current setting, respectively. The color rendering index of the LED lighting device can thus be adjusted flexibly.

Abstract: An LED lighting device includes multiple luminescent devices driven by a rectified AC voltage. The multiple luminescent devices are turned on flexibly in a multi-stage driving scheme using multiple current control units. At least one charge storage unit is coupled in parallel with at least one luminescent device. When the rectified AC voltage is still insufficient to turn on the at least one luminescent device, the at least charge storage unit is configured to discharge energy to the at least one luminescent device, thereby keeping the at least one luminescent device turned on.

Abstract: A technique analyzes an image to be displayed on a screen, before it is displayed, to determine a current draw of that image on the screen. Based on this analysis, adjustments can be made to the circuitry so that when the image is displayed, it is done so more efficiently. In a specific implementation, a DC-to-DC converter includes two boost converter circuits. Based on the analyzed image, the technique turns on a single boost converter when the current draw of that image is below an identified current threshold level, and turns on two boost converters when above the identified current threshold level.

Abstract: An LED lighting device includes a slave driving stage and a master driving stage. The slave driving stage includes a first luminescent device and a first current controller for providing a constant current setting in an ON phase. The master driving stage includes a second luminescent device and a current control unit having a second current controller and a current envelope controller. The second current controller provides a current envelope in the ON phase. The current envelope controller sets a level of the current envelope according to a rectified AC voltage. The driving current is regulated by the first current controller according to the constant current setting when the constant current setting is smaller than the level of the current envelope, or by the second current controller according to the current envelope when the level of the current envelope is smaller than the constant current setting.

Abstract: A digitally controlled voltage generator is disclosed for use in applications requiring fine resolution voltage control, such as generating a common voltage for a liquid crystal display. A constant resistance digital to analog converter (DAC) is configured to provide appropriate voltage steps by tuning bias resistors to generate desirable reference voltages for the DAC. The bias resistors are configured to be tuned after placement and routing steps in an integrated circuit design.

Abstract: One or more resistors or resistances are integrated in a 7-bit DVR or PVCOM integrated circuit. A 7-bit DVR or PVCOM integrated circuit includes a 7-bit DAC. The integrated resistors or resistances (R1, R2, or RSET, or any combination) reduces the number of external components, reduces the number of pins, and increases the accuracy of the DVR or PVCOM circuit. The least significant bit (LSB) of the DAC depends only on ratios of internal resistors, which can be made very accurate and independent of temperature.

Abstract: An LED lighting device includes multiple driving stages. A first driving stage includes a first luminescent device driven by a first current and a first current controller coupled in parallel with the first luminescent device. The first current controller is configured to conduct a second current according to a voltage established across the first current controller and regulate the second current so that a sum of the first current and the second current does not exceed a first value. The second driving stage includes a second luminescent device driven by a third current and a second current controller coupled in series to the second luminescent device. The second current controller is configured to conduct a fourth current according to a voltage established across the second current controller and regulate the fourth current so that a sum of the third current and the fourth current does not exceed a second value.

Abstract: An LED lighting device includes multiple driving stages. A first driving stage includes a first luminescent device driven by a first current, a second luminescent device driven by a second current, a path-controller for conducting a third current, a first current controller for regulating the first current, and a second current controller for regulating the second current. The second driving stage includes a third current controller coupled in series to the first driving stage and configured to conduct and regulate a fourth current. When the path-controller is turned off, the third current is zero, and the fourth current is equal to the sum of the first current and the second current. When the path-controller is turned on, the first current, the second current, the third current and the fourth current is equal.

Abstract: In one embodiment, a method includes: detecting one of a short-to-ground condition and a short-to-supply condition at an output node; after a delay, selectively activating a feedback control transistor according to the detecting; detecting a first current passing through a first transistor using a second transistor sized to be smaller than the first transistor; mirroring the detected current using a plurality of transistors to form a feedback current; and providing the feedback current to a gate electrode of the first transistor according to the selectively activating the feedback control transistor.

Abstract: An LED lighting device includes a first luminescent device, a second luminescent device, a first current controller and a second current controller. The first current controller is coupled in parallel with the first luminescent device and configured to operate according to a first current setting, a switch-on voltage and a switch-off voltage. The second current controller is coupled in series to the second luminescent device and configured to operate according to a second current setting. The first current setting, the second current setting, the switch-on voltage and the switch-off voltage are adjusted by setting the mode selection pins of the first and second current controllers.

Abstract: A digitally controlled voltage generator is disclosed for use in applications requiring fine resolution voltage control, such as generating a common voltage for a liquid crystal display. A constant resistance digital to analog converter (DAC) is configured to provide appropriate voltage steps by tuning bias resistors to generate desirable reference voltages for the DAC. The bias resistors are configured to be tuned after placement and routing steps in an integrated circuit design.

Abstract: One or more resistors or resistances are integrated in a 7-bit DVR or PVCOM integrated circuit. 7-bit DVR or PVCOM integrated circuit includes a 7-bit DAC. The integrated resistors or resistances (R1, R2, or RSET, or any combination) reduces the number of external components, reduces the number of pins, increases the accuracy of the DVR or PVCOM circuit. The least significant bit (LSB) of the DAC depends only on ratios of internal resistors, which can be made very accurate and independent of temperature.

Abstract: An LED lighting device includes multiple driving stages. A first driving stage includes a first luminescent device driven by a first current, a second luminescent device driven by a second current, a path-controller for conducting a third current, a first current controller for regulating the first current, and a second current controller for regulating the second current. The second driving stage includes a third current controller coupled in series to the first driving stage and configured to conduct and regulate a fourth current. When the path-controller is turned off, the third current is zero, and the fourth current is equal to the sum of the first current and the second current. When the path-controller is turned on, the first current, the second current, the third current and the fourth current is equal.

Abstract: A backlight driver includes current sources that are connected between LED strings and a number of bias voltages. There can be any number of different bias voltages, each at a ground potential or higher voltage. The bias voltage is selected for a particular LED string in order to reduce a current drop across the current source. This reduces the power consumption of the current source and LED string. Heat dissipation is also reduced.