UCD74106 Datasheet, PDF (1/28 Pages) Texas Instruments – Synchronous-Buck Power Stage External Bias Supply

UCD74106
www.ti.com
Synchronous-Buck Power Stage
Check for Samples: UCD74106
SLUSAJ5 – MAY 2011
FEATURES
1
• Fully Integrated Power Switches With Drivers
for Single and Multiphase Synchronous Buck
Converters
• Full Compatibility With TI Fusion Digital Power
Supply Controllers, (UCD91xx and UCD92xx
Families)
• Compatible With Analog Domain Controllers
• Wide Input Voltage Range:
– 4.5 V to 14 V
– Operational Down to 2.2-V Input With an
External Bias Supply
• Up to 6-A Output Current
• Operational to 2-MHz Switching Frequency
• Current Limit With Current Limit Flag
• Onboard Regulated 6-V Driver Supply From
VIN
• Thermal Protection and Monitoring
APPLICATIONS
• Digitally-Controlled Synchronous-Buck Power
Stage for Single and Multi-Phase Applications
• High Efficiency Small Size Regulators for
Desktop, Server, Telecom and Notebook
Applications
• Synchronous-Buck Power Stages
DESCRIPTION
The UCD74106 is a complete power system ready to
drive a buck power supply (Figure 1). High-side
MOSFETs, low-side MOSFETs, drivers, current
sensing circuitry and necessary protection functions
are all integrated into one monolithic solution to
facilitate minimum size and maximum efficiency.
Driver circuits provide high charge and discharge
current for the high-side NMOS switch and the
low-side NMOS synchronous rectifier in a
synchronous buck circuit. The MOSFET gates are
driven to 6.25 V by an internally regulated V_GG
supply. The internal V_GG regulator can be disabled to
permit the user to supply an independent gate drive
voltage. This flexibility allows a wide power
conversion input voltage range of 2.2 V to 18 V.
Internal Under Voltage Lockout (UVLO) logic insures
V_GG is good before allowing chip operation.
A drive logic block allows operation in one of two
modes. In synchronous mode, the logic block uses
the PWM signal to control both the high-side and
low-side gate drive signals. Dead time is optimized to
prevent cross conduction. The synchronous rectifier
enable (SRE) pin controls whether or not the low-side
FET is turned on when the PWM signal is low.
Simplified Application Diagram
R2
R1
UCD74106
4 PWM
VIN 13
3 SRE
2 FLT
TMON 10
12 FLTRST BST 1
11 IMON
SW 6
5 VGG
PGND 7
C2
BP3 AGND
9
8
C4
C1
C3 L1
C3
1
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas
Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
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 © 2011, Texas Instruments Incorporated