MJ10005

4

Motorola Bipolar Power Transistor Device Data

IC(pk)

t

t1

tf

t

IC

VCE

VCEO(sus)

VCEX(sus) AND INDUCTIVE SWITCHING

RESISTIVE SWITCHING

Lcoil = 10 mH, VCC = 10 V

Rcoil = 0.7 Ω

Vclamp = VCEO(sus)

Lcoil = 180 µH

Rcoil = 0.05 Ω

VCC = 20 V

Vclamp = Rated VCEX Value

VCC = 250 V

RL = 25 Ω

Pulse Width = 50

µs

t2

TIME

tf CLAMPED

VCE or

Vclamp

tf UNCLAMPED [ t2

20

1

0

PW Varied to Attain

IC = 250 mA

2

INDUCTIVE TEST CIRCUIT

INDUCTIVE TEST CIRCUIT

t1 Adjusted to

Obtain IC

Test Equipment

Scope — Tektronix

475 or Equivalent

RESISTIVE TEST CIRCUIT

OUTPUT WAVEFORMS

1

INPUT

2

Rcoil

Lcoil

VCC

Vclamp

RS =

0.1

Ω

1N4937

OR

EQUIVALENT

TUT

SEE ABOVE FOR

DETAILED CONDITIONS

1

INPUT

2

Rcoil

Lcoil

VCC

Vclamp

RS =

0.1

Ω

1N4937

OR

EQUIVALENT

TUT

SEE ABOVE FOR

DETAILED CONDITIONS

1

2

TUT

RL

VCC

t1 ≈

Lcoil (IC

pk

)

VCC

t2 ≈

Lcoil (IC

pk

)

VClamp

Table 1. Test Conditions for Dynamic Performance

Figure 7. Inductive Switching Measurements

TIME

tsv

trv

tfi

tti

90% Vclamp

tc

90% IB1

IB

10%

IC

2%

IC

Vclamp

IC

Vclamp

10%

Vclamp

90% IC

SWITCHING TIMES NOTE

In resistive switching circuits, rise, fall, and storage times

have been defined and apply to both current and voltage wa-

veforms since they are in phase. However, for inductive

loads which are common to SWITCHMODE power supplies

and hammer drivers, current and voltage waveforms are not

in phase. Therefore, separate measurements must be made

on each waveform to determine the total switching time. For

this reason, the following new terms have been defined.

tsv = Voltage Storage Time, 90% IB1 to 10% Vclamp

trv = Voltage Rise Time, 10–90% Vclamp

tfi = Current Fall Time, 90–10% IC

tti = Current Tail, 10–2% IC

tc = Crossover Time, 10% Vclamp to 10% IC

An enlarged portion of the turn–off waveforms is shown in

Figure 7 to aid in the visual identity of these terms.