IR2085S Datasheet, PDF (1/9 Pages) International Rectifier – HIGH SPEED, 100V, SELF OSCILLATING 50% DUTY CYCLE, HALF-BRIDGE DRIVER

Data Sheet No. PD60206 Rev.C
IR2085S & (PbF)
HIGH SPEED, 100V, SELF OSCILLATING 50% DUTY CYCLE,
Features
HALF-BRIDGE DRIVER
• Simple primary side control solution to enable half-bridge
Product Summary
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
V_{CC (max)}
V_offset(max)
High/low side
25V
100Vdc
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
Description
output freq (f_osc)
500kHz
Output Current (I_O)
+/-1.0A(typ.)
High/low side pulse
width matching
+/- 25ns
Package
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.
Each channel frequency is equal to f_osc, where f_osc can be set by selecting R_T & C_T,
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
S O -8
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)
Vb
S1
C₂
Vcc
HO
R_T
OSC
Vs
C_T
C _BIAS
S₂
C₁
Cs
LO
GND
S _R1
L
C R V_o
S _R2
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