1
VR11.1, VR12 Compatible Synchronous Rectified Buck
MOSFET Driver
ISL6627
The ISL6627 is a high frequency MOSFET driver designed to drive
upper and lower power N-Channel MOSFETs in a synchronous
rectified buck converter topology. The advanced PWM protocol of
ISL6627 is specifically designed to work with Intersil VR11.1,
VR12 controllers and combined with N-Channel MOSFETs to form
a complete core-voltage regulator solution for advanced
microprocessors. When ISL6627 detects a PSI
protocol sent by
an Intersil VR11.1, VR12 controller, it activates Diode Emulation
(DE) operation; otherwise, it operates in normal Continuous
Conduction Mode (CCM) PWM mode.
To further enhance light load efficiency, the ISL6627 enables
diode emulation operation during PSI
mode. This allows
Discontinuous Conduction Mode (DCM) by detecting when the
inductor current reaches zero and subsequently turning off the
low side MOSFET to prevent it from sinking current.
When ISL6627 detects Diode Braking command from the PWM,
it turns off both gates and reduces overshoot in load transient
situations.
An advanced adaptive shoot-through protection is integrated to
prevent both the upper and lower MOSFETs from conducting
simultaneously and to minimize dead time. The user also has the
option to program the driver working in fixed propagation delay
mode to optimize the regulator efficiency. The ISL6627 has a
20kΩ integrated high-side gate-to-source resistor to prevent self
turn-on due to high input bus dV/dt.
Related Literature
• Technical Brief TB363 “Guidelines for Handling and Processing
Moisture Sensitive Surface Mount Devices (SMDs)”
• Technical Brief TB417
“Designing Stable Compensation
Networks for Single Phase Voltage Mode Buck Regulators”
Features
• Intersil VR11.1 and VR12 Compatible
• Dual MOSFET Driver for Synchronous Rectified Bridge
• Advanced Adaptive Zero Shoot-through Protection
• Programmable Fixed Deadtime for Efficiency Optimization
• Low Standby Bias Current
• 36V Internal Bootstrap Diode
• Bootstrap Capacitor Overcharge Prevention
• Supports High Switching Frequency
- 4A Sinking Current Capability
- Fast Rise/Fall Times and Low Propagation Delays
• Integrated High-Side Gate-to-Source Resistor to Prevent Self
Turn-on Due to High Input Bus dV/dt
• Power Rails Undervoltage Protection
• Expandable Bottom Copper Pad for Enhanced Heat Sinking
• Dual Flat 10 Ld (3x3 DFN) Package
- Near Chip-Scale Package Footprint; Improves PCB Efficiency
and Thinner in Profile
• Pb-Free (RoHS Compliant)
Applications
• High Light Load Efficiency Voltage Regulators
• Core Regulators for Advanced Microprocessors
• High Current DC/DC Converters
• High Frequency and High Efficiency VRM and VRD
EN
VCC
PWM
+5V
33.6k
28.8k
BOOT
UGATE
PHASE
LGATE
GND
SHOOT-
THROUGH
PROTECTION/
20kΩ
CONTROL
LOGIC
POR/
TD
DELAY
PROGRAMMING
FIGURE 1. ISL6627 BLOCK DIAGRAM
January 24, 2014
FN6992.1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 1-888-468-3774
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