LED display as a high-tech products has attracted people's attention, the use of computer control, the light, the integration of large-screen intelligent LED display has been used to a large range. LED outdoor large screen manufacturers below for you to explain the LED display driver chip.
LED display pixels to take LED light-emitting diodes, many light-emitting diodes to lattice array, constitute the LED array, and then constitute the LED display. Through different LED drive method, you can get different results of the image. So the advantages and disadvantages of driving the chip, the display quality of the LED display has played a very important role.
LED driver chip can be divided into two kinds of general-purpose chips and special chips.
1, general-purpose chip is generally used for LED display low-end products, such as indoor single, two-color LED display. The most commonly used general-purpose chip is the 74HC595, with 8-bit latch, serial - and shift memory and tri-state output. Each channel can output up to 35 mA of current (not constant current). General IC manufacturers can produce such chips.
2, for full-color display dedicated chip, because the LED is the current characteristics of the device, that is, under the premise of saturation conduction, the brightness changes with the size of the current changes, not with the voltage changes at both ends of the change The Therefore, one of the biggest features of a dedicated chip is the supply of constant current sources. Constant current source can ensure a solid LED drive, dispel the LED flashing phenomenon.
LED display dedicated chip important parameters:
LED display chip with a large output current, constant current and other basic features, practical for high current, high quality places, such as outdoor full color, indoor full color and so on.
LED display dedicated chip performance parameters have the maximum output current, current output error (bit to bit, chip to chip), constant current source and the number of data shift clock and so on.
Maximum output current:
At present the mainstream of the constant current source chip maximum output current is defined as a single maximum output current, generally about 90 mA. Constant current is the basic characteristics of a dedicated chip, but also to get the basic high quality. And the maximum value of the constant current (ie, the maximum constant output current) is output for each channel at the same time. The display is more meaningful because the constant current is output at the same time in the white balance condition. Generally the maximum constant current output current is less than the maximum allowable output current.
Current output error:
The current output error is divided into two kinds, one is the inter-bit current error, that is, the error between each chip output; the other is the inter-chip current error, that is, the output error between different chips. Current output error is a very important parameter, the display of a great impact on the uniformity. The greater the error, the worse the display uniformity, it is difficult to make the screen body to reach the white balance.