LM5026_15 Datasheet, PDF (1/33 Pages) Texas Instruments – LM5026 Active Clamp Current Mode PWM Controller

LM5026
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SNVS363D – AUGUST 2005 – REVISED APRIL 2013
LM5026 Active Clamp Current Mode PWM Controller
Check for Samples: LM5026
FEATURES
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•2 Current Mode Control
• Internal 100V Start-up Bias Regulator
• 3A Compound Main Gate Driver
• High Bandwidth Opto-coupler Interface
• Programmable Line Under-Voltage Lockout
(UVLO) with Adjustable Hysteresis
• Versatile Dual Mode Over-Current Protection
with hiccup delay timer
• Programmable Overlap or Deadtime between
the Main and Active Clamp Outputs
• Programmable Maximum Duty Cycle Clamp
• Programmable Soft-start
• Leading Edge Blanking
• Resistor Programmed 1MHz Capable Oscillator
• Oscillator Sync I/O Capability
• Precision 5V Reference
PACKAGES
• TSSOP-16
• WSON-16 (5x5 mm) Thermally Enhanced
DESCRIPTION
The LM5026 PWM controller contains all of the
features necessary to implement power converters
utilizing the active clamp / reset technique with
current mode control. With the active clamp
technique, higher efficiencies and greater power
densities can be realized compared to conventional
catch winding or RDC clamp / reset techniques. Two
control outputs are provided, the main power switch
control (OUT_A) and the active clamp switch control
(OUT_B). The device can be configured to control
either a P-Channel or N-Channel clamp switch. The
main gate driver features a compound configuration,
consisting of both MOS and Bipolar devices,
providing superior gate drive characteristics. The
LM5026 can be configured to operate with bias
voltages over a wide input range of 8V to 100V.
Additional features include programmable maximum
duty cycle, line under-voltage lockout, cycle-by-cycle
current limit, hiccup mode fault operation with
adjustable timeout delay, PWM slope compensation,
soft-start, 1MHz capable oscillator with
synchronization input / output capability, precision
reference and thermal shutdown.
Typical Application Circuit
V_IN
36 - 78V
V_OUT
3.3V
T1
CS
V_CC
V_IN
LM5026
CS
UVLO _{OUT_A}
TIME
RES
RT
OUT_B
REF
COMP
DCL
SYNC
SS
PGND AGND
SYNC I/O
ERROR
AMP and
ISOLATION
Figure 1. Simplified Forward Power Converter with Active Clamp Reset
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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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