PMOLED is an OLED (Organic Light Emitting Diode) display based on organic materials. It has the advantages of ultra-thin, high brightness and low power consumption. It has a wide range of applications in information display, portable devices, automotive displays, electronic games and watches. . The driving circuit and control method of PMOLED directly affect its performance and quality.

 

1. PMOLED drive circuit

PMOLED is made of conductive polymer and organic semiconductor material, and its drive circuit mainly includes two modes: AMS (Active Matrix Drive) and PDS (Passive Matrix Drive).

1. AMS method

The AMS method is to complete the display through row scanning and column selection. It is characterized by fast working speed, short response time, low current consumption, and can support high frame rate, high resolution and multiple gray levels. The circuit of AMS mode is divided into static drive circuit and dynamic drive circuit.

Static drive circuit: each pixel has an independent memory unit, which can store display information, and the pixel is lit by gating the row and column during the display process.

Dynamic drive circuit: put all the memory units of the pixels in a shift register, and put the row address outputted by the row address encoder into the shift register first, and then put the column address into the shift register in order. In the bit register, finally realize the lighting of the pixel by selecting the row and column.

2. PDS method

The PDS method is a passive matrix circuit composed of a group of organic thin film transistors and capacitors. The principle is to store relevant data through capacitors, and then realize the lighting of pixels under the control of transistors through capacitor charges.

The resolution and frame rate of the passive matrix circuit are strictly limited due to the need to store the driving signals required by each pixel, but its circuit design is simple and the manufacturing cost is low, so it is suitable for small-sized displays.

 

2. PMOLED control method

The control methods of PMOLED displays mainly include serial and parallel methods, and the parallel methods are further divided into static parallel and dynamic parallel.

1. Serial mode

The serial method is to transmit the grayscale or color signal output by the controller to the PMOLED interface board through the serial interface, and then decompose the signal to drive each pixel to light up.

Since the serial method only needs to transmit a small amount of data, it does not require a large number of pins and wiring, which can effectively reduce manufacturing costs and system power consumption, and is suitable for small-sized displays.

2. Parallel mode

The parallel method is to transmit the grayscale or color signal output by the controller to the PMOLED interface board through the parallel interface, and then transmit the signal to each pixel driving circuit through static parallel or dynamic parallel to complete the lighting of the pixel.

The static parallel method is to output the data of each pixel through the same pin and circuit line. Since the data path is the same, the waveform of the gray scale is also the same, and an additional isolation capacitor is required. Static parallelism is suitable for smaller displays.

The dynamic parallel method is to decompose the pixel data into rows and columns and send them in an interleaved manner. The switch state of each pixel is controlled by the pixel pin. The dynamic parallel method can support high resolution, high refresh rate and multi-level brightness control, but Due to the large number of pixel pins and the complex data path, more power consumption and cost are required.

 

To sum up, the driving circuit and control method of PMOLED have an important impact on the performance and quality of the display. Different application scenarios need to choose the appropriate driving circuit and control method to achieve the best performance and effect.