Datasheet

16
Step 2: Check the ACPL-3130 Power Dissipation and Increase R
g
if
Necessary. The ACPL-3130 total power dissipation (P
T
) is equal to
the sum of the emitter power (P
E
) and the output power (P
O
):
= 8 W, Max Duty Cycle = 80%, Q
g
= 500 nC, f = 20 kHz and
T
A
max = 85˚C:
PE Parameter Description
I
F
LED Current
V
F
LED On Voltage
Duty Cycle Maximum LED Duty Cycle
PO Parameter Description
I
CC
Supply Current
V
CC
Positive Supply Voltage
V
EE
Negative Supply Voltage
E
SW(Rg,Qg)
Energy Dissipated in the ACPL-3130 for
each IGBT Switching Cycle (See Figure 31)
f Switching Frequency
For the circuit in Figure 30 with I
F
(worst case) = 16 mA, R
g
Figure 31. Energy Dissipated in the ACPL-3130 for Each IGBT Switching
Cycle.
The value of 4.25 mA for I
CC
in the previous equation was
obtained by derating the I
CC
max of 5 mA (which occurs at
-40°C) to I
CC
max at 85˚C (see Figure 7).
Since P
O
for this case is greater than P
O(MAX)
, R
g
must be
increased to reduce the ACPL-3130 power dissipation.
For Q
g
= 500 nC, from Figure 31, a value of E
SW
= 4.65 µW
gives a R
g
= 10.3 Ω.
Esw - ENERGY PER SWITCHING CYCLE - µJ
0
0
Rg - GATE RESISTANCE - Ω
50
6
10
14
20
4
30 40
12
Qg = 100 nC
Qg = 500 nC
Qg = 1000 nC
10
8
2
V
CC
= 19 V
V
EE
= -9 V
( )
fQ;REVIPPP
DutyCycle
VIP
PPP
ggSWCCCCG)O(SWITCHINO(BIAS)O
FFE
OET
+=+=
=
+=
•
•
•
•
( ) ( ) ( )
93mW
85mW178mW
P-PP
BIASOMAXOMAX SWITCHINGO
=
=
=
( )
( )
µW65.4
20kHz
93mW
P
E
MAX SWITCHINGO
MAX SW
==
=
f
-
( )
(
CmW/8.4C15-250mWC@85PmW178
mW189
mW104mW85
20kHzµJ2.5V204.25mAP
23mW0.81.8V16mAP
MAX
O
O
E
°�°=°>
=
+=
�+�=
=��=
•
•
•
•
)
•