Ocp Test Function - ITech IT8700P+ Series User Manual

Enter Esc
9. Press
need to set the Vd value.
CR-LED Vdorp=
Enter
10. Press
Calculation method of Vd and R
Definition:

V: constant working voltage of load LED of LED constant current source;

I: output current of LED constant current source;

Vd: break-over voltage of diode (string);

R: constant resistance.
V-I curve of LED is as shown below.
According to four parameters above and the V-I curve of LED, you can
calculate the value of R and Vd .
=
R
=
V
d
Or you can calculate the value of R and Vd by the following method.
Vd=V*0.8
R=0.2V/I

4.15 OCP Test Function

IT8700P+ series electronic load is provided with over-current protection test
function (OCP Test). Under OCP test mode, when input voltage reached Von
value, delay for a while for the electronic load to latch. Ascend value by step
value at regular interval. At the same time, check the load input voltage and
judge whether it is higher than standard voltage value. If higher, it indicates that
OCP does not occur. Repeat current stepping operation till the load operates to
the cutoff current; if lower, it indicates that OCP does occur. Check whether the
▼ ▼
key to move to Vd= 0.000V. Press
0.000V
Esc
Esc Esc
key to exit
−
V V
2 1
−
I I
2 1
( )
− ×
V I R
o 0
NOTE
The value of V2, V1, I2 and I1should be close to the static working point of LED as shown
in the red circle above.
Copyright © Itech Electronic Co., Ltd.
Operations introduction
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key to confirm. You
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