Mikpower, Inc.

Oki Semiconductor, Ltd.

Thomas Chao

John Huang

Chung-Jen Chien

Chingchi Yao

Methods and circuits for controlling one or more LEDs are disclosed. In one embodiment, a light emitting diode (LED) driver for driving one or more serially connected LEDs includes a voltage regulator circuit configured to receive a rectified AC voltage, where the voltage regulator circuit includes a depletion device configured to generate an unregulated voltage using the rectified AC voltage, a band gap voltage reference circuit configured to generate one or more reference voltages using the unregulated voltage, and a current setting circuit configured to control the one or more serially connected LEDs using the one or more reference voltages, where the current setting circuit is connected to a circuit ground through a current setting resistor having a fixed resistance value.

LED controller

Methods and circuits for controlling LEDs are disclosed. In one embodiment, a multistage driver for driving a plurality of serially connected LEDs includes a voltage regulator circuit configured to receive a rectified AC voltage, where the voltage regulator circuit includes a depletion device configured to generate a unregulated voltage using the rectified AC voltage, a band gap voltage reference circuit configured to generate a plurality of reference voltages using the unregulated voltage, and a current setting circuit configured to control the plurality of serially connected LEDs using the plurality of reference voltages.

Methods and circuits for controlling LEDs are disclosed. In one embodiment, the light emitting diode (LED) integrated circuit controller includes a voltage regulator circuit configured to operate with an alternating current (AC) power source, where the voltage regulator circuit includes a depletion device configured to receive a varying AC voltage and to generate a unregulated voltage, and a band gap voltage reference circuit configured to received the unregulated voltage and to generate a substantially constant direct current (DC) voltage. The LED integrated circuit controller further includes a current setting circuit configured to receive the substantially constant DC voltage and to provide a substantially constant direct current to drive a series of light emitting diodes, and a second depletion device configured to protect the LED integrated circuit controller from external high voltages.

A dynamic random access memory (DRAM) cell includes first and second MOS transistors, such as a PMOS transistor and NMOS transistor in a CMOS cell. One of the two transistors functions as a switch transistor while the other transistor is configured as a storage capacitor. The DRAM cell may be integrated into a logic device, such as a CMOS gate array, using PMOS and NMOS transistor cells formed in the gate array. In that case, the DRAM cell may be fabricated in a logic device with the standard processes used to produce the logic device.

Growing community of inventors

Cupertino, CA, United States of America

Thomas Chao