LM5041B_15 Datasheet, PDF (1/20 Pages) Texas Instruments – Cascaded PWM Controller

LM5041B
www.ti.com
SNVS605 – MAY 2009
LM5041B Cascaded PWM Controller
Check for Samples: LM5041B
FEATURES
1
•2 Internal Start-up Bias Regulator
• Programmable Line Under-Voltage Lockout
(UVLO) with Adjustable Hysteresis
• Current Mode Control
• Internal Error Amplifier with Reference
• Cycle-by-cycle Over-Current Protection
• Leading Edge Blanking
• Programmable Push-Pull Overlap or Dead
Time
• Internal 1.5A Push-Pull Gate Drivers
• Programmable Soft-Start
• Programmable Oscillator with Sync Capability
• Precision Reference
• Thermal Shutdown
APPLICATIONS
• Telecommunication Power Converters
• Industrial Power Converters
• Multi-Output Power Converters
PACKAGES
• TSSOP-16
• WSON-16 (5x5 mm) Thermally Enhanced
DESCRIPTION
The LM5041B PWM controller contains all of the
features necessary to implement either current-fed or
voltage-fed push-pull or bridge power converters.
These “Cascaded” topologies are well suited for
multiple output and higher power applications. The
LM5041B includes these four control outputs: the
buck stage controls (HD and LD) and the push-pull
control outputs (PUSH and PULL). Push-pull outputs
are driven at 50% nominal duty cycle at one half of
the switching frequency of the buck stage and can be
configured for either a specified overlap time (for
current-fed applications) or a specified non-overlap
time (for voltage-fed applications). Push-pull stage
MOSFETs can be driven directly from the internal
gate drivers while the buck stage requires an external
driver such as the LM5102. The LM5041B includes a
high-voltage start-up regulator that operates over a
wide input range of 15V to 100V. The PWM controller
is designed for high-speed capability including an
oscillator frequency range up to 1 MHz and total
propagation delays of less than 100 ns. Additional
features include line Under-Voltage Lock-Out
(UVLO), Soft-Start, an error amplifier, precision
voltage reference, and thermal shutdown.
The differences between LM5041, LM5041A and
LM5041B are as follows: In the LM5041A and the
LM5041B version, the hiccup mode over-current
protection is not employed and the VCC bias
regulator is not disabled by a low state at the SS pin.
In the LM5041B version, both the high and low side
buck stage gate drivers are forced to a low state
when the controller is disabled. In the LM5041 and
the LM5041B version, the buck stage controller is
disabled by either a low state at the UVLO pin or a
low state at the SS pin. Also in the LM5041B version,
the REF pin 5V regulator is not disabled by a UVLO
pin low state.
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.
Copyright © 2009, Texas Instruments Incorporated