I feel that the chips on the main board of the LED advertising screen have dense lines. I don't know where to start and how to carry his lines
Author:Wang Donghua Time:2021-10-11 08:05 Browse(12)
LED display maintenance information
The function of 74hc245 is to amplify the signal power.

I feel that the chips on the main board of the LED advertising screen have dense lines. I don't know where to start and how to carry his lines


the first pin dir is used to convert the input and output ports. The high-level signal is input from the "a" end and output from the "B" end, and the low-level signal is input from the "B" end and output from the "a" end.

the second to ninth pin "a" signal is input and output.
A1=B1,,,,,, a8=B8, A1 and B1 are a group, If dir="1" g="0", A1 input B1 output, other similar.
If dir="0" g="0", B1 input A1 output.
other similar.

11 ~ 18 pin "B" signal input and output terminal.
function is the same as "a" terminal, not described.

19 pin g.
enable terminal, if the pin is "1" A / b terminal signal will not conduct, only when it is "0", a / b terminal will be enabled, The pin acts as a switch.
the 10th pin GND, power supply ground.

the 20th pin VCC.
the positive pole of the power supply.

the 74hc04 acts as a 6-bit inverter.

the 7th pin GND.
the power supply ground.

the 14th pin VCC.
the positive pole of the power supply.

the signal is input from the a-end and output from the y-end in reverse phase.
A1 and Y1 are a group, and so on.
for example: if A1="1", Y1="0",

If A1="1", then Y1="0",
If Y1=

If A1="1 The function of other groups is the same.


the function of 74HC138 is: 8-bit binary decimal decoder.

the 8th pin GND.
the function of 74HC138 is: 8-bit binary decimal decoderPower supply ground.

VCC of the 15th pin.
positive pole of power supply
A, B, C of the 1st to 3rd pins, and binary input pins.

chip selection signal control of the 4th to 6th pins.
only when the 4th and 5th pins are "0" and the 6th pin is "1", can the VCC be selected, and the output is controlled by a, B, and C C signal control.
any other combination mode will not be gated.
and the output of Y0 ~ Y7 is all "1"

cascade by controlling the gating pin.
expand it to 16 bits.

example: G2A=0.
G2B=0, G1=1, a=1, B=0, C=0, then Y0 is "0" and Y1 ~ Y7 is "1", For details, see the truth table.


functions of 74HC595: LED driver chip.
8-bit shift latch.

GND of the 8th pin.
power supply ground.

VCC of the 16th pin.
positive pole of the power supply
data of the 14th pin, serial data input port. The display data can enter from this, and can only be moved in with the cooperation of the clock signal.

en of the 13th pin.
enable port, When the pin is "1", all the QA ~ QH ports are "1". When the pin is "0", the output of QA ~ QH is controlled by the input data.

the 12th pin STB.
the latch port. When the input data is transferred into the register, only by supplying a latch signal can the moved data be sent to the QA ~ QH port for output.

the 11th pin CLK.
the clock port, Each clock signal will move one bit of data into the register.

the 10th pin SCLR.
reset port. As long as there is a reset signal, the data moved into the register will be cleared,The display screen does not use this pin, but is generally connected to the VCC.

the 9th pin dout.
serial data output terminal, which transmits the data to the next.

the 15th and 1st to 7th pins.
the parallel output port, that is, the drive output port, drives the LED.


the function of 4953: row drive tube.
power tube.

its internal is two CMOS tubes.
the 1st and 3rd pin VCC, the 2nd and 4th pin control pins, the 2nd pin controls the outputs of 7th and 8th pins, and the 4th pin controls the outputs of 5th and 7th pins Functions of TB62726: LED driver chip, 16 bit shift latch.

GND of pin 1.
power supply ground.

VCC of pin 24.
power supply positive pole
data of pin 2, serial data input
CLK of pin 3, clock input
STB of pin 4, latch input
output current adjusting terminal of pin 23, Other functions are similar to 74HC595, except that TB62726 is a 16 bit shift latch with output current adjustment function, but there is no high level on the parallel output port, Only high resistance state and low-level state.
74HC595 parallel output has high-level and low-level output.
TB62726 and 5026 have the same pin function.
the structure is similar.
check online.
or go directly to the computer market.
I'm in Beijing.
small and medium-sized LED manufacturers have counters in Zhongguancun.
I'm in BeijingLarge manufacturers are generally located in Shenzhen and other places.
there are agents or integrators in various places.
.
the main manufacturers are in Shenzhen and other places
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