Abstract: In a backlight scaling method and system, the pixel values of a first frame are counted to obtain a first histogram of this frame simultaneously when the first frame is inputted to the data driver ICs, and a first backlight luminance generated according to the first histogram is applied to the backlight driver for the backlight scaling for a second frame when the derived second frame is inputted to the data driver after the pixel values of the second frame is recalculated by the first backlight luminance. In the same way, when the derived second frame is inputted to the data driver, the original pixel values of the second frame are counted to obtain a second histogram of this frame and to generate a second backlight luminance for the third frame, and so on. Because the backlight luminance for each frame is generated according to the histogram of the previous frame, only small amount of pixel buffers for the processing is required.

Abstract: A LED driver providing a LED lighting current to a LED path, extracts the LED lighting current information from the LED path to produce a first signal including an AC component and a DC component, and extracts the DC component information of the first signal to produce a second signal to regulate an average of the LED lighting current. This LED driver implements real constant average current regulation for a LED lighting apparatus, eliminates the need of output capacitor as well as rectifier diode in most applications to simplify the circuit of the power stage, and is applicable to power stages of various modes.

Abstract: The output current of a power converter is sensed for triggering a quick transient response when the variation of the output current reaches a default value, and therefore the output voltage of the power converter is promptly stabilized earlier by removing the time delay to trigger the quick transient response.

Abstract: A booster power management integrated circuit chip includes first and second output pads, a transistor switch coupled between the first and second output pads and having a gate, and a trigger circuit coupled between the first and second output pads and further coupled to the gate of the transistor switch. The trigger circuit drives the transistor switch to conduct when an instantaneous voltage larger than a trigger voltage level is present between the first and second output pads so as to enable electric current to flow through the transistor switch.

Abstract: An amplifier circuit with internal zeros provides a second pole in addition to a first pole and two zeros such that the second pole can prevent excessive gain at high frequency, so as to have high-frequency noise under control.

Abstract: In an adaptive leading-edge blanking circuit and method for a switching mode power converter, an inductor current of the converter is sensed and compared with a threshold to decide an end point of a leading-edge blanking time. Circuit and method are further provided for preventing the converter from entering pulse skipping mode, which employs a current trimming circuit in an oscillator for a PWM controller in the converter to reduce a charging current in the oscillator if the output voltage of the converter is excessively high, to thereby reduce the oscillator frequency and in turn lower the switching frequency of a high-side power switch of the converter.

Abstract: The present invention discloses a short circuit protection circuit comprising: a first input terminal; a second input terminal; an output terminal; at least two transistors including a first and a second transistors connected in series with each other and electrically connected between the first input terminal and the output terminal; and a voltage source circuit electrically connected with the first input terminal, the second input terminal, the output terminal, and the gates of the first and second transistors.

Abstract: In an apparatus for over-voltage and over-current protection for a step-up current-mode converter including an inductor connected via a phase node to a switch that is switched by a control signal to convert an input voltage to an output voltage, a controller has a multiplexed pin, and a resistor and a capacitor are connected in parallel between the multiplexed pin and the phase node. In an over-voltage protection mode, the controller senses the voltage on the multiplexed pin, and in an over-current protection mode, the controller supplies a current to flow through the resistor and senses the voltage on the multiplexed pin.

Abstract: The present invention discloses a backlight control circuit with flexible configuration, comprising: a light emitting device path; a current source for controlling the current amount on the light emitting device path, the current source receiving a relatively high reference voltage in a first state, and receiving a relatively low reference voltage in a second state; and a current source control circuit for controlling the current source, whereby when the light emitting device path is in normal use, the current source is set to the first state, and when the light emitting device path is not in normal use, the current source is set to the second state.

Abstract: The present invention discloses a backlight control circuit capable of distinguishing an under current condition, comprising: at least one light emission device path having a voltage node; at least one current source for controlling the current amount on the light emission device path; and at least one under current detection circuit for generating a first control signal according to the voltage at the voltage node, wherein when the first control signal changes its state, the under current detection circuit generates a second control signal to change the voltage on the voltage node if the light emission device path is normally connected.

Abstract: The present invention discloses a power supply comprising: a switching regulator circuit converting an input voltage to an intermediate voltage; a low dropout linear regulator circuit converting the intermediate voltage to an output voltage so as to supply a load current to a load; and a feedback control circuit which increases the noise filtering effect of the low dropout linear regulator circuit when the load current increases.

Abstract: The present invention discloses a power-saving control circuit for an OLED panel, comprising: a plurality of OLEDs respectively located in a corresponding plurality of paths; a current amount determination circuit determining current amounts on the plurality of paths; a voltage supply circuit under control by a control signal, for providing an output voltage to the current amount determination circuit; and a matching feedback adjustment circuit for generating the control signal according to a difference among the current amounts of the plurality of paths.

Abstract: The present invention discloses an analog photovoltaic power circuit, comprising: a photovoltaic device group for receiving photo energy to generate an input voltage; a power stage circuit for converting the input voltage to an output voltage; an optimum voltage estimation circuit for receiving a predetermined voltage and estimating an optimum voltage according to a direction of variation of the input voltage and a direction of variation of the power generated by the photovoltaic device group; and an analog comparison and control circuit for comparing the optimum voltage with the input voltage, to thereby control the operation of the power stage circuit.

Abstract: In a gamma voltage generator and gamma voltage generating method that can tune the gamma voltages individually, several gamma currents of a same magnitude are generated for each to flow through a variable resistive element to generate a variable common voltage and several variable voltages, from which a common gamma voltage and several first gamma voltages are generated. By use of the symmetric property of the gamma curve corresponding to those gamma voltages to be generated, several voltages are generated by mapping the first gamma voltages with the common gamma voltage as the center axis, and from which several second gamma voltages are derived. The common gamma voltage and the first and second gamma voltages are provided for those gamma voltages corresponding to the gamma curve.

Abstract: A voltage generating circuit, which generates tri-state logic output in accordance with high, low or floating of the input node, is proposed.

Abstract: The present invention discloses a level shift circuit which comprises: level shift means for receiving an input of a first operational voltage and generating an output of a second operational voltage; and a current path connecting with a source of the second operational voltage and providing current to the output of the level shift means to speed up output level switching. The circuit preferably further comprises a power consumption control circuit for stopping excess power consumption when the output of the level shift means has substantially accomplished level switching.

Abstract: The present invention discloses a backlight control circuit, comprising: a voltage supply circuit, which is a boost converter circuit for receiving an input voltage from an input terminal and generating an output voltage to an output terminal, the output voltage being provided as an operating voltage for a plurality of light emitting devices; at least one input capacitor electrically connected between the input terminal and ground; and at least one output capacitor electrically connected between the output terminal and the input terminal.

Abstract: The present invention discloses a backlight control circuit, comprising: a voltage supply circuit, under control by a control signal, for receiving an input voltage and generating an output voltage; a plurality of nodes for respectively indicating the current status of corresponding light emission device paths; and a high-low voltage comparison and amplifier circuit for generating the control signal according to a voltage difference between at least two nodes.

Abstract: The present invention discloses a backlight control circuit, and a method for controlling light emission devices. The method comprises: providing a plurality of light emission device paths connected in parallel; and setting a total current of the paths connected in parallel to a constant.

Abstract: The present invention discloses a backlight control circuit, comprising: a voltage supply circuit for receiving an input voltage and generating an output voltage under control by a control signal; at least one voltage comparison path respectively coupled to at least one light emission device path; a voltage operative amplifier circuit for generating the control signal according to a lowest voltage on the at least one voltage comparison path; and at least one under current detection circuit for detecting whether a corresponding one of the at least one light emission device path is in an under current status, whereby when anyone of the under current detection circuits detects the under current status, it sends an exclusion signal excluding a corresponding one of the at least one voltage comparison path from being an effective input of the voltage operative amplifier.