The dot matrix brightness of single chip computer is inconsistent
Driving ability is different from line to field. "The feeling is that when you move up and down, you pass the resistance, and you move around as if there is no resistance," and you feel right. That's true.
The cause of this problem is because the microcontroller is a column (row), a column (row) one by one scan, if the scan to the first column (row) with 1 LED light, scanning to the next column (row) when there are 2 LED lights, the two column (row) brightness the lamp will not, because the second column (row) LED than the first column (row) of the LED, according to the parallel series voltage dividing the second column (row) LED current is the first column (row) half of the LED current, so it is darker.
With the MOS line (4953) connected to a power supply, the gate of MOS transistor by MCU controlled directly or by 74138 after decoding control, 62726 control lines, 62726 is the constant current driver, serial input and parallel output, designed for LED lattice design driven.
Brightness is not enough, you can increase the drive current or change the scanning cycle, 1/8 scan must be much brighter than the 1/16 scan. In scanning mode, the driving current of LED can be increased to 50mA, and usually no problem. In static driving mode, 20mA current comparison insurance is adopted.
