Constant current drive. Current LED display is basically driven by constant current. The constant current drive is to add a constant current source to the ground pin of the light-emitting chip, so that the current through the chip is unchanged when the external power supply changes, so as to avoid the chip damage. Constant current drive can be divided into static constant current drive.
LED display is a kind of high definition, high brightness, high stability display equipment, widely used in indoor and outdoor various occasions. This article will introduce the drive mode and scanning mode of LED display to help readers better understand this device. Constant current drive and constant voltage drive Constant current drive and constant voltage drive are LED displayTwo driving methods.
In general, if you are pursuing the ultimate brightness stability of LED display, constant current drive is undoubtedly your first choice; If you're looking for something economical and easy to handle, constant pressure drives are a cost-effective solution. / When selecting a driver mode, you must determine the driver mode based on actual requirements and application scenarios.
LED driver chips can be divided into general purpose chips and special chips. General purpose chips are generally used for low-end LED display products, such as indoor single and two-color LED display screens. The most commonly used general-purpose chip is the 74HC595, which has an 8-bit lockStore, string, shift register and tri-state output function.
1, LED driver chip can be divided into general chip and special chip two. The so-called universal chip, the chip itself is not specifically designed for LED, but some logic chips with some logic functions of the LED display (such as series-and-shift registers). The special chip refers to the driver chip designed specifically for the LED display according to the LED luminous characteristics.
2245,138,4953,5024 and other chips in the LED display function as follows: 245 is to control transceiver, for input and output. Enhance the output driving ability of single chip microcomputer. 138 is decoded, which can save ports, because the led display uses more pins, and can not be connected without decoding.
3, LED driver chip can be divided into general chip and special chip. General purpose chips are generally used for low-end LED display products, such as indoor single and two-color LED display screens. The most commonly used general-purpose chip is 74HC595, which has an 8-bit latch and string shiftBit register and three-state output function.
4. Drive problem. Each row or column is not displayed, that is, the corresponding driver circuit (chip) problem, and the replacement can display the problem. Long-term use of LED display may damage aging, maintenance can be replaced.
5, and a built-in shaker for PWM function. DM412 and MOJAY, M8914, M8910 are LED driver chips with pulse width modulation PWM output and enable control, designed for LED lighting, LED display, decoration and other applications.
The backlight chip is an electronic component commonly used in the backlight module of the display screen. How to properly disconnect the protection circuit to ensure its normal operation is always an important problem. This paper will introduce the method of disconnecting 9902 backlight chip protection circuit from three aspects. First of all, understanding the 9902 backlight chip protection circuit is the key.
SIRF. In the promotion of HaoZhixin navigation, we learned that the chip model of this product is SIRF, which is a new invention, and HaoZhixin Navigation is suitable for the navigation device of Audi cars.
TOSHIBA: Toshiba Semiconductor is a major supplier of automotive leds, especially dashboard backlights, car radio, navigation systems, climate control and other units. The technology used is InGaAlP, with wavelengths ranging from 560nm (puregreen) to 630nm (red).
General purpose chip General purpose chip is generally used for low-grade LED display products, such as indoor monochrome screen, two-color screen and so on. The most commonly used general-purpose chip is the 74HC595. The 74HC595 features an 8-bit latch, series-parallel shift register, and three-state output. Maximum per pathCan output 35mA current (non-constant current). General IC manufacturers can produce such chips.
1, MOJAY M8900 is a raw side feedback, with single-stage active PFC high precision LED constant current control chip, M8900 integrated single-stage active PFC line, can achieve higher power factors and very low total harmonic distortion, the chip can enter quasi-resonant mode, so as to achieve higher efficiency and reduceThe switching loss.
2, mainstream brand IC have LED driver IC! Like PI, ST, NXP, Maxim, Fairchild, TI... These companies all have suitable LED driver ics. Of course, now Taiwan, domestic manufacturers also have many programs to choose from.
3, Wei Chuang Electronics (Shenzhen) Co., LTD., the contract, keep promises, ensure product quality, with a variety of business characteristics and the principle of small profits and quick sales, won the trust of customers.