ELECTRICAL CHARACTERISTICS:
PIN DESCRIPTIONS
A, B:
Signal and power input pins. Connect these pins to
the secondary of the transformer driven by UC1726.
CLAMP:
Analog programming pin for intermediate drive
level to be used at turn on or in response to a desatura-
tion event. Requires a bypass capacitor to COM.
COM:
Self generated common for bipolar supply. This
pin will be 16.5V below PV
CC
.
D
SAT+
, D
SAT-
:
Inputs to the desaturation comparator. De-
saturation is detected when D
SAT+
is greater than D
SAT-
.
ENBL:
Negative true enable input. Tie to V
CC
to disable
the chip. Connect to COM to enable the chip. If the ENBL
pin is used as the primary input to the chip, connect B to
V
CC
and A to V
EE
.
FRC:
Fault Resistor and Capacitor. Programs the dura-
tion that OUT will be held at CLAMP potential during a de-
saturation event before it is driven fully low. Also sets the
period of time that OUT will be held low before allowing it
to be driven high again.
FRPLY:
Fault Reply pin. Open collector output. Normally
connected to V
EE
. When desaturation is detected, the pin
opens.
OUT:
Gate drive output. Connect to gate of IGBT with a
series damping resistor greater than 3 ohms.
TRC:
Timing Resistor and Capacitor. Programs the dura-
tion that OUT will be held at CLAMP potential and the pe-
riod of time the desaturation comparator will be ignored
during the rising edge.
V
CC
:
Positive supply voltage. Bypass to COM with a low
ESL/ESR 1
μ
F capacitor.
V
EE
:
Negative supply voltage. Bypass to COM with a low
ESL/ESR 1
μ
F capacitor.
PV
EE
:
Output driver negative supply. Connect to V
EE
with a 3.3 ohm resistor and bypass to COM with a low
ESL/ESR 1
μ
F capacitor.
PV
CC
:
Output driver positive supply. Connect to V
CC
with
a 3.3 ohm resistor and bypass to COM with a low
ESL/ESR 1
μ
F capacitor.
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNITS
Power Input Receivers
Forward Diode Drop
I
F
= 50mA
I
F
= 500mA
0.5
1.2
0.65
2
V
V
V
CC
Regulator
V
CC
Hysteresis Comparator
Input Open Circuit Voltage
Input Impedance
Hysteresis
Enable Input
High Level Input Voltage
Low Level Input Voltage
Input Bias Current
Output Driver
Saturation to V
CC
Saturation to V
CC
Saturation to V
EE
Saturation to V
EE
25
≤
(V
CC
- V
EE
)
≤
36V,
I(COM)
≤
15mA
15.5
16.5
17.5
V
(Measured with respect to V
EE
)
12
100
47
V
k
V
44
50
12
V
V
μ
A
5
ENBL = COM
460
900
I(OUT) = -20mA
I(OUT) = -500mA
I(OUT) = 20mA
I(OUT) = 500mA
1.7
2
2
2.4
2.3
2.5
3
3.6
V
V
V
V
Unless otherwise stated, these specifications apply for T
A
=
55
°
C to 125
°
C for the
UC1727, T
A
=
40
°
C to 85
°
C for the UC2727, T
A
= 0
°
C to 70
°
C for the UC3727,
R(TRC) = 54.9k, C(TRC) = 180pF, R(FRC) = 309K, C(FRC) = 200pF, V
CC
- V
EE
=
25V, CLAMP = 9V, T
A
= T
J,
and all voltages are measured with respect to COM.
UC1727
UC2727
UC3727
See Application Note U-143A "New Chip Pair Provides Isolated Drive for High Voltage IGBTs"
3
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