Himax Technologies, Inc.

Chih-Heng Chu

Ming-Cheng Chiu

Tian-Hau Chen

A current driving apparatus and method using a pulse width modulation (PWM) technique to display a desired gray level for passive matrix organic light emitting diode (PMOLED) display applications is disclosed. The current driving circuit includes a memory, a logic and a segment driver. The memory stores a desired gray level, the logic comprises a counter and provides a predetermined bias time, and the segment driver provides a constant current to the PMOLED display based on the desired gray level and the predetermined bias time. The segment driver provides a constant current to the PMOLED display until the counter value reaches the desired gray level, and the counter is first counted zero for the predetermined bias time and then increments by one for every other cycle.

Driving circuit using pulse width modulation technique for a light emitting device

A source driver comprising a frame memory, a first line buffer, and a second line buffer. The frame memory stores bits of pixel values of an image. The first line buffer then sequentially latches the bits of the pixel values from the frame memory with a first address index. The second line buffer then sequentially latch the bits of the pixel values from the first line buffer with a second address index, which is different from the first address index, and writes the bits of the pixel values back to the frame memory, such that the image is scrolled. The present invention also provides a method of refreshing the frame memory in a source driver.

Source driver for image scrolling

A method for writing data into the memory, especially a method of preventing the data from overwriting for the write operation, is disclosed. The invention provides a control device for a memory system, which utilizes at least two layers of latches to hold the inputted data from a data bus and the data which prepares to be written into memory respectively. According to the control of communication between two layers of latches by the control device, the new inputted data of the succeeding write operation will not overwrite the data of the current write operation, thereby reducing the limitation for the cycle of writing (CYCW) and increasing the write speed.

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Tainan County, Taiwan

Chih-Heng Chu