A question about LED Display Board

[arm_learner]

Hi All,

Now, I am doing a LED Display Board. From the method of scanning for implementing the picture, I have a question.

- 60Hz (16ms) per picture
- 5 Rows (3.3ms per row)

Q1: Do I need to apply more than 5 times operating current for LED more brightness? because the brightness is too weak.

Thanks!

 

[saowaluck]

May be the answers useful for you :
1. Do u have back-light.
2. From I observed I see the LED board which This board have the small size LED is very beautiful(light)more than the big size LED and the blackground is black colour.

 

[arm_learner]

May be the answers useful for you :
1. Do u have back-light.
2. From I observed I see the LED board which This board have the small size LED is very beautiful(light)more than the big size LED and the blackground is black colour.

So, I apply the normal operation current is ok?

Thanks

 

[papyaki]

Hi,

I think you can apply a current value that do not exceed the led's peak current (see led's datasheet) and which give a average value equal to the normal current value.

For example, if led normal current is 10mA and led is on 3.3ms every 16ms, this give a value of ((16ms/3.3ms) * 10mA) = 48.5mA . With this value, average current is equal to 10mA. Check if 48,5mA is not over the led's peak current.

 

[bigaussie]

well minimum refreshing rate of a group of leds (rows/columns) should be atleast 50Hz. on time of column/row depends on no. of columns/rows.

for column by column multiplexing,
for 60 columns
each should have 50hz
so total period =20ms
on time of a column=20ms/60=333us
since each column has duty cycle of 1/60th average current =peak current/60

so for 60mA peak current; average current is 1mA

also you can't exceed max.peak current rating of leds

big aussie