SCALE Driver

2SD315AI Data Sheet

IGBT-Driver.com

Page 11

Notes on Table 1

The values for “Vth1” and “Vth2” are

listed in Table 1 as a function of the

reference resistance Rth.

The value in the “Vth1” column cor-

responds to the voltage threshold

after the response time has elapsed.

The value in the “Vth2” column cor-

responds to the voltage which is set

up statically across the resistor Rth.

This static value is typically reached

after between 10 and 15 µs.

The value in the “VCE(off)” column

corresponds to the collector-emitter

voltage value at which the protection

function is activated when the

external circuit is used as shown in

Fig. 4 with one or two Dm diodes of

type 1N4007 connected in series.

A value of 1n5 is used for the

response time capacitor Ca. If this

capacitor is rated higher or lower, the

response time changes in proportion

to the change in capacitance, whereas

the thresholds Vth1 and Vth2 remain

practically

unchanged

(they

are

specified by Rth).

Value Rth Reaction

time

Vth1

Vth2

VCE(off)

22k

 4.9s

 4.8V

 3.2V

2.35V (1 Diode)

27k

 5.7s

 5.6V

 3.9V

3.05V (1 Diode)

33k

 6.8s

 6.5V

 4.7V

3.25V (2 Diodes)

39k

 7.6s

 7.3V

 5.6V

4.15V (2 Diodes)

47k

 9s

 8.4V

 6.8V

5.35V (2 Diodes)

Table 1 Reference resistor, reaction time and turn-off threshold with Ca = 1n5

+Vdc

0V

Vth

Response time

Detail view

Detail

0V

Vce

Vth1

Vce

Vth2

Fig. 5 Collector-sense voltage curve