ICP-S データシートの表示（PDF） - ROHM Semiconductor

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ICP-S

Overcurrent Protection Elements

ROHM Semiconductor 

Overcurrent Protection Elements

ICP-S Technical Manual

Joule Integral Calculation of Irregularly Increasing or Decreasing Current

Current mode: Irregular wave form + triangular wave form

Model: ICP-S1.2

Wave form:

10A

Actual wave form

8A

6A

Approximation curve for Joule

integral calculation

3.5A

2A

0.1ms 0.35ms

0.25ms

0.55ms

Wave form approximation: The above wave form (electric charge wave form) is approximated as an

irregular wave form to calculate the Joule integral of the wave form.

Test:

Item

Peak Segmented

current period

Joule integral

Accumu- Lapsed

lation time

No.

Im

(A)

t

(ms)

Formula

Coefficient × Im2 × t A2 • ms)

1 10 0.06 10×8×0.06+1/3×(10−8)2×0.06=

2

8 0.1 8×6×0.1+1/3×(8−6)2×0.1=

3

6 0.35 6×3.5×0.35+1/3×(6−3.5)2×0.35=

4 3.5 0.25 3.5×2×0.25+1/3×(3.5−2)2×0.25=

5

2 0.55 1/3×(2)2×0.55=

(A2 • ms) (ms)

4.88 4.88 0.06

4.93 9.81 0.16

8.07 17.88 0.51

1.93 19.81 0.76

0.73 20.54 1.31

Plotting test:

100000

Ta=25°C

10000

1000

A : Effective pulse breaking

line (with no margin)

4

5

3

100

2

10 1

B : Effective pulse critical

line (with no margin)

1

0.1

0.001

C : Effective pulse recommended

line (with margin)

0.01 0.1

1

10 100 1000 10000 100000

Time (msec)

I2 t-t Characteristic Curve (ICP-S1.2)

Test results: The steady-state current is between lines B and A. Therefore, it is considered that the

ICP-S will deteriorate or break the current due to the repetitive pulses.

Rev.A 10/13

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