參數(shù)資料
型號(hào)： HCPL-J456
英文描述： Intelligent Power Module and Gate Drive Interface Optocouplers(智能功率模塊和門驅(qū)動(dòng)接口光耦合器)
中文描述： 智能功率模塊和門極驅(qū)動(dòng)接口光電耦合器（智能功率模塊和門驅(qū)動(dòng)接口光耦合器）
文件頁數(shù)： 17/20頁
文件大?。?/td> 289K
代理商： HCPL-J456
17
LED Drive Circuit
Considerations for Ultra
High CMR Performance
Without a detector shield, the
dominant cause of optocoupler
CMR failure is capacitive coupl-
ing from the input side of the
optocoupler, through the
package, to the detector IC
as shown in Figure 16. The
HCPL-4506 series improve
CMR performance by using a
detector IC with an optically
transparent Faraday shield, which
diverts the capacitively coupled
current away from the sensitive
IC circuitry. However, this shield
does not eliminate the capacitive
coupling between the LED and
the optocoupler output pins and
output ground as shown in Figure
17. This capacitive coupling
causes perturbations in the LED
current during common mode
transients and becomes the
major source of CMR failures
for a shielded optocoupler. The
main design objective of a high
CMR LED drive circuit becomes
keeping the LED in the proper
state (on or off) during common
mode transients. For example,
the recommended application
circuit (Figure 15), can achieve
15 kV/
μ
s CMR while minimizing
component complexity. Note that
a CMOS gate is recommended
in Figure 15 to keep the LED
off when the gate is in the high
state.
Another cause of CMR failure for
a shielded optocoupler is direct
coupling to the optocoupler
output pins through C
LEDO1
and
C
LEDO2
in Figure 17. Many factors
influence the effect and magni-
tude of the direct coupling
including: the use of an internal
or external output pull-up
resistor, the position of the LED
current setting resistor, the
connection of the unused input
package pins, and the value of the
capacitor at the optocoupler
output (C
L
).
Techniques to keep the LED in
the proper state and minimize the
effect of the direct coupling are
discussed in the next two
sections.
CMR with the LED On
(CMR
L
)
A high CMR LED drive circuit
must keep the LED on during
common mode transients. This is
achieved by overdriving the LED
current beyond the input
threshold so that it is not pulled
below the threshold during a
transient. The recommended
minimum LED current of 10 mA
provides adequate margin over
the maximum I
TH
of 5.0 mA (see
Figure 1) to achieve 15 kV/
μ
s
CMR. Capacitive coupling is
higher when the internal load
resistor is used (due to C
LEDO2
)
and an I
F
= 16 mA is required to
obtain 10 kV/
μ
s CMR.
The placement of the LED current
setting resistor effects the ability
of the drive circuit to keep the
LED on during transients and
interacts with the direct coupling
to the optocoupler output. For
example, the LED resistor in
Figure 18 is connected to the
anode. Figure 19 shows the AC
equivalent circuit for Figure 18
during common mode transients.
During a +dVcm/dt in Figure 19,
the current available at the LED
anode (Itotal) is limited by the
series resistor. The LED current
(I
F
) is reduced from its DC value
by an amount equal to the current
that flows through C
LEDP
and
C
LEDO1
. The situation is made
worse because the current
through C
LEDO1
has the effect of
trying to pull the output high
(toward a CMR failure) at the
same time the LED current is
being reduced. For this reason,
the recommended LED drive
circuit (Figure 15) places the
current setting resistor in series
with the LED cathode. Figure 20
is the AC equivalent circuit for
Figure 15 during common mode
transients. In this case, the LED
current is not reduced during a
+dVcm/dt transient because the
current flowing through the
package capacitance is supplied
by the power supply. During a
-dVcm/dt transient, however, the
LED current is reduced by the
amount of current flowing
through C
LEDN
. But, better CMR
performance is achieved since the
current flowing in C
LEDO1
during a
negative transient acts to keep the
output low.
Coupling to the LED and output
pins is also affected by the con-
nection of pins 1 and 4. If CMR is
limited by perturbations in the
LED on current, as it is for the
recommended drive circuit
(Figure 15), pins 1 and 4 should
be connected to the input circuit
common. However, if CMR
performance is limited by direct
coupling to the output when the
LED is off, pins 1 and 4 should be
left unconnected.
CMR with the LED Off
(CMR
H
)
A high CMR LED drive circuit
must keep the LED off
(V
F
≤
V
F(OFF)
) during common
mode transients. For example,
during a +dVcm/dt transient in
Figure 20, the current flowing
through C
LEDN
is supplied by the
parallel combination of the LED
and series resistor. As long as the
voltage developed across the
resistor is less than V
F(OFF)
the
相關(guān)PDF資料
PDF描述
HCPL-0466 Intelligent Power Module and Gate Drive Interface Optocouplers(智能功率模塊和門驅(qū)動(dòng)接口光耦合器)
HCPL-M454 Ultra High CMR, Small Outline,5 Lead, High Speed Optocoupler(超高CMR，小型，5引線，高速光耦合器)
HCPL-M700 Small Outline, 5 Lead, Low Input Current, High Gain Optocouplers(小型，5引線，低輸入電流，高增益光耦合器)
HCPL-M701 Small Outline, 5 Lead, Low Input Current, High Gain Optocouplers(小型，5引線，低輸入電流，高增益光耦合器)
HCPL-T250 1.5 Amp Output Current IGBT Gate Drive Optocoupler(1.5 Amp 輸出電流IGBT門驅(qū)動(dòng)光耦合器)
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
HCPL-J456#300 功能描述:邏輯輸出光電耦合器 1MBd 1Ch 10mA RoHS:否 制造商:Fairchild Semiconductor 絕緣電壓:4243 Vrms 輸出類型:Push-Pull 最大傳播延遲時(shí)間:500 ns 最大正向二極管電壓: 最大反向二極管電壓: 最大正向二極管電流: 最大連續(xù)輸出電流:2.5 A 最大功率耗散:100 mW 最大工作溫度:+ 100 C 最小工作溫度:- 40 C 封裝 / 箱體:SO-16 封裝:Tube
HCPL-J456#500 功能描述:邏輯輸出光電耦合器 1MBd 1Ch 10mA RoHS:否 制造商:Fairchild Semiconductor 絕緣電壓:4243 Vrms 輸出類型:Push-Pull 最大傳播延遲時(shí)間:500 ns 最大正向二極管電壓: 最大反向二極管電壓: 最大正向二極管電流: 最大連續(xù)輸出電流:2.5 A 最大功率耗散:100 mW 最大工作溫度:+ 100 C 最小工作溫度:- 40 C 封裝 / 箱體:SO-16 封裝:Tube
HCPL-J456-000E 功能描述:邏輯輸出光電耦合器 1MBd 1Ch 10mA RoHS:否 制造商:Fairchild Semiconductor 絕緣電壓:4243 Vrms 輸出類型:Push-Pull 最大傳播延遲時(shí)間:500 ns 最大正向二極管電壓: 最大反向二極管電壓: 最大正向二極管電流: 最大連續(xù)輸出電流:2.5 A 最大功率耗散:100 mW 最大工作溫度:+ 100 C 最小工作溫度:- 40 C 封裝 / 箱體:SO-16 封裝:Tube
HCPL-J456-300E 功能描述:邏輯輸出光電耦合器 1MBd 1Ch 10mA RoHS:否 制造商:Fairchild Semiconductor 絕緣電壓:4243 Vrms 輸出類型:Push-Pull 最大傳播延遲時(shí)間:500 ns 最大正向二極管電壓: 最大反向二極管電壓: 最大正向二極管電流: 最大連續(xù)輸出電流:2.5 A 最大功率耗散:100 mW 最大工作溫度:+ 100 C 最小工作溫度:- 40 C 封裝 / 箱體:SO-16 封裝:Tube
HCPL-J456-500E 功能描述:邏輯輸出光電耦合器 1MBd 1Ch 10mA RoHS:否 制造商:Fairchild Semiconductor 絕緣電壓:4243 Vrms 輸出類型:Push-Pull 最大傳播延遲時(shí)間:500 ns 最大正向二極管電壓: 最大反向二極管電壓: 最大正向二極管電流: 最大連續(xù)輸出電流:2.5 A 最大功率耗散:100 mW 最大工作溫度:+ 100 C 最小工作溫度:- 40 C 封裝 / 箱體:SO-16 封裝:Tube
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