Data Sheet No. PD60206 Rev.C
IR2085S & (PbF)
HIGH SPEED, 100V, SELF OSCILLATING 50% DUTY CYCLE,
HALF-BRIDGE DRIVER
Features
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Simple primary side control solution to enable half-bridge
DC-Bus Converters for 48V distributed systems with reduced
component count and board space.
Integrated 50% duty cycle oscillator & half-bridge driver IC in a
single SO-8 package
Programmable switching frequency with up to 500kHz max per
channel
+/- 1A drive current capability optimized for low charge MOSFETs
Adjustable dead-time 50nsec – 200nsec
Floating channel designed for bootstrap operation up to +100Vdc
High and low side pulse width matching to +/- 25nsec
Adjustable overcurrent protection
Undervoltage lockout and internal soft start
Also available LEAD-FREE
Product Summary
V
CC (max)
25V
100Vdc
V
offset(max)
High/low side
output freq (f
osc
)
500kHz
Output Current (I
O
)
+/-1.0A(typ.)
High/low side pulse
width matching
+/- 25ns
Description
The IR2085S is a self oscillating half-bridge driver IC with 50% duty cycle ideally
suited for 36V-75V half-bridge DC-bus converters. This product is also suitable for
push-pull converters without restriction on input voltage.
Package
Each channel frequency is equal to f
osc
, where f
osc
can be set by selecting R
T
& C
T
,
S O -8
where f
osc
≈
1/(2*R
T
.C
T
). Dead-time can be controlled through proper selection of C
T
and can range from 50 to 200nsec. Internal soft-start increases the pulse width during
power up and maintains pulse width matching for the high and low outputs throughout the start up cycle. The
IR2085S initiates a soft start at power up and after every overcurrent condition. Undervoltage lockout prevents
operation if V
CC
is less than 7.5Vdc.
Simplified Circuit Diagram
Vbias
(10-15V)
D
BOOT
C
BOOT
Vin
( 100V max)
V
cc
V
b
HO
S
1
C
2
IR2085
R
T
C
T
C
BIAS
OSC
S
R1
L
S
R2
C
R
V
o
V
s
Cs
GND
LO
S
2
C
1
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