LM5021
www.ti.com
SNVS359D –MAY 2005–REVISED MARCH 2013
LM5021 AC-DC Current Mode PWM Controller
Check for Samples: LM5021
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FEATURES
DESCRIPTION
The LM5021 off-line pulse width modulation (PWM)
controller contains all of the features needed to
implement highly efficient off-line single-ended
flyback and forward power converters using current-
mode control. The LM5021 features include an ultra-
low (25 µA) start-up current, which minimizes power
losses in the high voltage start-up network. A skip
cycle mode reduces power consumption with light
loads for energy conserving applications (ENERGY
STAR®, CECP, etc.). Additional features include
under-voltage lockout, cycle-by-cycle current limit,
hiccup mode overload protection, slope com-
pensation, soft-start and oscillator synchronization
capability. This high performance 8-pin IC has total
propagation delays less than 100nS and a 1MHz
capable oscillator that is programmed with a single
resistor.
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Ultra Low Start-up Current (25 µA maximum)
Current Mode Control
Skip Cycle Mode for Low Standby Power
Single Resistor Programmable Oscillator
Synchronizable Oscillator
Adjustable Soft-Start
Integrated 0.7A Peak Gate Driver
Direct Opto-Coupler Interface
Maximum Duty Cycle Limiting (80% for
LM5021-1 or 50% for LM5021-2)
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Slope Compensation for (LM5021-1 Only)
Under Voltage Lockout (UVLO) with Hysteresis
Cycle-by-Cycle Over-Current Protection
Hiccup Mode for Continuous Overload
Protection
WHITE SPACE
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Leading Edge Blanking of Current Sense
Signal
Packages: VSSOP-8 or PDIP-8
Simplified Application Diagram
VOUT
+
AC
90 ~ 264 Vac
VCC
VIN
LM5021
RT
SS
OUT
CS
+
COMP GND
FEEDBACK
WITH
ISOLATION
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PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
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