Iml International

Alberto Giovanni Viviani

Dimitry Goder

ChinFa Kao

Chiayao S Tung

Chun Lu

Yung-Hsin Chiang

Yi-Mei Li

JunGi Lee

Kai-Yun Cheng

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.

Driving LEDs in backlight for flat panel display

A VCOM generator circuit generates a VCOM signal for an electronic display. The VCOM circuit includes an operational amplifier having reduced supply rails. In an implementation, the VCOM circuit has at least three supply rails, AVDD, ground or GND, and VP or VN, or both. VP is less than AVDD and greater than VN. VN is higher than ground and below VP. The VCOM circuit with reduced voltage supply rails for VP and VN reduces power consumption of the VCOM op amps. By reducing power consumption, this also reduces the surface temperature of the integrated circuit.

VCOM with reduced supply rails

A voltage converter includes a low dropout regulator voltage converter circuit. The voltage converter generates three voltages (e.g., 1.2 volts, 2.5 volts, and 1.8 volts) for an electronic system, which can be a smartphone or electronic tablet or other device. An implementation has at least one charge pump voltage converter circuit. The low dropout regulator voltage converter circuit provides an output voltage based on its input voltages and can operate with a very small input-to-output differential voltage. Compared to using a Buck converter, a low dropout regulator does not have an external inductor, which saves space. An implementation of the voltage converter can also include at least one charge pump voltage converter circuit to generate a voltage of the voltage converter.

Voltage converter with buck converter and low dropout regulator

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 (R, R, 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.

Current mode digitally variable resistor or programmable VCOM

A voltage converter includes at least one charge pump voltage converter circuit. The voltage converter generates three voltages (e.g., 1.2 volts, 2.5 volts, and 1.8 volts) for an electronic system, which can be a smartphone or electronic tablet or other device. The charge pump voltage converter circuit provides an output voltage that is an average of its input voltages. Compared to a low dropout regulator, charge pump voltage converter circuit has high efficiency. This voltage converter will save power compared to converters using a low dropout regulator. An implementation of the voltage converter can includes at least two charge pump voltage converter circuits to generate to different output voltages.

Floating charge pump voltage converter

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.

Current mode DVR or PVCOM with integrated impedances

Driving LEDs in LCD backlight

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 Vor 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.

Light-emitting diode lighting device having multiple driving stages and line/load regulation control

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 (R, R, 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.

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Mountian View, CA, United States of America

Alberto Giovanni Viviani