User: alciro    User
 Original    Translate to:  Deutsch  English  Français  中文  
 

Domótica sencilla, fácil y económica

 Introduction to home automation network free microHomeLan
 Economic issues in home automation installations

3. PWM Regulator Diode LED (PowerLed)

3.1. 3A PowerLed Uhlan V1.0

Prototype dimmer circuit PWM (pulse width modulation, Pulse-width modulation) to control current. Switching regulator current limit of 3 amps adjustable from 0 to 3A depending on the power LED diode with which to work, to get an energy efficiency between 80% and 90%, and increase the life of the LED diode power control the labor system and the operating temperature.

PWM regulator Prototype V1.0 3A PowerLed Uhlan plant automation

3.1.1. Current regulator diode LED

PWM controller for LED diodes, 3A PowerLed

The current limit in PWM controller switched to LED diodes is determined by the equation:

R_x\ =\ \frac{1,5}{I(A)}\ =\ (\Omega )

Where

  • I is the desired current value in amperes.
  • Rx is the limiting resistance value formed by R5, R6 and R7.

For example for a current of 0.8 A.

R_x\ =\ \frac{1,5}{0,8A}\ =\ 1,875\Omega

The resistance of 1.875 Ω is necessary, this can be replaced by three parallel resistance of 5.6 Ω power of less, formed by resistors R5, R6 and R7 are shown in Fig.

LED diode intensity

The following table shows the value of the current limiting resistor Rx and power dissipation for different values ​​of LED current. The values ​​of resistors R5, R6 and R7 corresponds to a possible equivalent combination that has the same / about limiting resistor value Rx.

I LED (A) Rx (Ω) P Rx (W)
R5 (Ω) R6 (Ω) R7 (Ω)
0,1 15 0,15 15 - -
0,2 7,5 0,3 15 15 -
0,3 5 0,45 10 10 -
0,4 3,75 0,6 7,5 7,5
-
0,5 3 0,75 6,8 6,8
27
0,6 2,5 0,9 7,5 7,5
7,5
0,7 2,1428 1,05 4,3
4,3
-
0,8 1,875 1,2 5,6 5,6
5,6
0,9 1,6666 1,35 3,3 3,3
-
1 1,5 1,5 3,3 3,3
18
1,5 1 2,25
2 0,75 3
2,5 0,6 3,75
3 0,5 4,5

Loading
copyright © 2007-2020  www.alciro.org  All rights reserved.         
Share |