© by SEMIKRON / 2020-05-25 / Technical Explanation / SKYPER
®
12 PV
PROMGT.1026/ Rev.7/ Template Technical Explanation
Page 28/37
Figure 19: SKYPER
12 PV | Dynamic short circuit protection
5.5.2
DSCP | Calculation hints
The following equations help to select all relevant parameters of the DSCP feature:
Equation (1)
Calculation of the static trip level
(𝑉
𝐶𝐸(𝑟𝑒𝑓)
= 𝑉
𝐶𝐸(𝑠𝑡𝑎𝑡)
)
𝑉
𝐶𝐸(𝑠𝑡𝑎𝑡)
= 𝑃𝑊𝑅_𝑉𝑆_𝑃 ⋅
𝑅
2_𝐶𝐹𝐺
𝑅
1_𝐶𝐹𝐺
+ 𝑅
2_𝐶𝐹𝐺
Equation (2)
Calculation of
𝑅
2_𝐶𝐹𝐺
for a certain value of
𝑉
𝐶𝐸(𝑠𝑡𝑎𝑡)
𝑅
2_𝐶𝐹𝐺
=
𝑅
1_𝐶𝐹𝐺
⋅ 𝑉
𝐶𝐸(𝑠𝑡𝑎𝑡)
𝑃𝑊𝑅_𝑉𝑆_𝑃 − 𝑉
𝐶𝐸(𝑠𝑡𝑎𝑡)
Equation (3)
Calculation of the blanking time
𝑡
𝑏𝑙(𝑉𝐶𝐸)
depending on the values of
𝐶
𝐶𝐹𝐺
; 𝑅
1_𝐶𝐹𝐺
; 𝑅
2_𝐶𝐹𝐺
; 𝑉
𝐶𝐸(𝑠𝑡𝑎𝑡)
𝑡
𝑏𝑙(𝑉𝐶𝐸)
= −𝐶
𝐶𝐹𝐺
⋅
𝑅
1_𝐶𝐹𝐺
⋅ 𝑅
2_𝐶𝐹𝐺
𝑅
1_𝐶𝐹𝐺
+ 𝑅
2_𝐶𝐹𝐺
⋅ ln (
10𝑉
𝑃𝑊𝑅_𝑉𝑆_𝑃
⋅ (𝑅
1_𝐶𝐹𝐺
+ 𝑅
2_𝐶𝐹𝐺
) − 𝑅
2_𝐶𝐹𝐺
𝑅
1_𝐶𝐹𝐺
)
Equation (4)
Calculation of the voltage
𝑉
𝐶𝐸(𝐼𝑁)
at the VCE_IN input depending on the values of
𝑉
𝐶𝐸
; 𝑅
𝑉𝐶𝐸
;
𝑉
𝐷_𝑉𝐶𝐸
𝑉
𝐶𝐸(𝐼𝑁)
=
𝑅
1
⋅ 𝑅
2
𝑅
1
⋅ 𝑅
2
+ (𝑅
1
+ 𝑅
2
) ⋅ 𝑅
𝑉𝐶𝐸
⋅ 𝑉
𝐶𝐸
+
(𝑉
𝐷_𝑉𝐶𝐸
+
𝑃𝑊𝑅_𝑉𝑆_𝑃 ⋅ 𝑅
𝑉𝐶𝐸
𝑅
1
) ⋅ 𝑅
1
⋅ 𝑅
2
𝑅
1
⋅ 𝑅
2
+ (𝑅
1
+ 𝑅
2
) ⋅ 𝑅
𝑉𝐶𝐸
5
10
15
V
t
V
CE(sat)
V
CE(ref)
V
CE
0
t
bl(VCE)
V
CE(stat)
V
CE(IN)
5
10
15
V
t
V
CE(sat)
V
CE(ref)
V
CE
0
t
bl(VCE)
V
CE(stat)
V
CE(IN)
V
5
10
15
t
V
CE(sat)
V
CE(ref)
V
CE
0
t
bl(VCE)
V
CE(stat)
V
CE(IN)
