LM5025A_14 Datasheet, PDF (1/22 Pages) Texas Instruments – Active Clamp Voltage Mode PWM Controller

LM5025A
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SNVS293D – DECEMBER 2004 – REVISED MARCH 2010
LM5025A Active Clamp Voltage Mode PWM Controller
Check for Samples: LM5025A
FEATURES
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•2 Internal Start-up Bias Regulator
• 3A Compound Main Gate Driver
• Programmable Line Under-Voltage Lockout
(UVLO) with Adjustable Hysteresis
• Voltage Mode Control with Feed-Forward
• Adjustable Dual Mode Over-Current Protection
• Programmable Overlap or Deadtime between
the Main and Active Clamp Outputs
• Volt x Second Clamp
• Programmable Soft-start
• Leading Edge Blanking
• Single Resistor Programmable Oscillator
• Oscillator UP / DOWN Sync Capability
• Precision 5V Reference
• Thermal Shutdown
DESCRIPTION
The LM5025A is a functional variant of the LM5025 active clamp PWM controller. The functional differences of
the LM5025A are: The CS1 and CS2 current limit thresholds have been increased to 0.5V. The internal CS2 filter
discharge device has been disabled and no longer operates each clock cycle. The internal V_CC and V_REF
regulators continue to operate when the line UVLO pin is below threshold.
The LM5025A PWM controller contains all of the features necessary to implement power converters utilizing the
Active Clamp / Reset technique. 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 two
internal compound gate drivers parallel both MOS and Bipolar devices, providing superior gate drive
characteristics. This controller is designed for high-speed operation including an oscillator frequency range up to
1MHz and total PWM and current sense propagation delays less than 100ns. The LM5025A includes a high-
voltage start-up regulator that operates over a wide input range of 13V to 90V. Additional features include: Line
Under Voltage Lockout (UVLO), softstart, oscillator UP/DOWN sync capability, precision reference and thermal
shutdown.
Packages
• TSSOP-16
• LLP-16 (5x5 mm) Thermally Enhanced
1
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2
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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