ir3084a International Rectifier Corp., ir3084a Datasheet - Page 7

• Manufacturer Part Number: ir3084a
• Description: Xphase Tm Vr 10/11 Control Ic
• Manufacturer: International Rectifier Corp.

SYSTEM THEORY OF OPERATION
XPhase
The XPhase
applications requiring small size, design flexibility, low voltage, high current and fast transient response. The
architecture can be used in any multiphase converter ranging from 1 to 16 or more phases where flexibility
facilitates the design trade off of multiphase converters. The scalable architecture can be applied to other
applications which require high current or multiple output voltages.
As shown in Figure 2, the XPhase
converters each using a single Phase IC. The Control IC communicates with the Phase ICs through a 5 wire
analog bus, i.e. bias voltage, phase timing, average current, error amplifier output, and VID voltage. The Control
IC incorporates all the system functions, i.e. VID, PWM ramp oscillator, error amplifier, bias voltage, and fault
protections etc. The Phase IC implements the functions required by the converter of each phase, i.e. the gate
drivers, PWM comparator and latch, over voltage protection, and current sensing and sharing.
There is no unused or redundant silicon with the XPhase
controller that can be configured for 2, 3, or 4 phase operation. PCB Layout is easier since the 5 wire bus
eliminates the need for point to point wiring between the Control IC and each Phase. The critical gate drive and
current sense connections are short and local to the Phase ICs. This improves the PCB layout by lowering the
parasitic inductance of the gate drive circuits and reducing the noise of the current sense signal.
ENABLE
VIDSEL
Page 7 of 45
12V
VID7
VID6
VID5
VID4
VID3
VID2
VID1
VID0
TM
Architecture
TM
architecture is designed for multiphase interleaved buck converters which are used in
IR3084
CONTROL
IC
>> BIAS VOLTAGE
>> PHASE TIMING
<< CURRENT SENSE
>> PWM CONTROL
>> VID VOLTAGE
CONTROL BUS
TM
Figure 2 – System Block Diagram
architecture consists of a Control IC and a scalable array of phase
PHASE FAULT
CURRENT SHARE
PHASE FAULT
CURRENT SHARE
ADDITIONAL PHASES
IR3086
PHASE
IC
IR3086
PHASE
IC
TM
architecture compared to others such as a 4 phase
CCS
CCS
RCS
RCS
INPUT/OUTPUT
CIN
COUT
IR3084A
10/30/2006
VOUT SENSE+
VOUT+
VOUT-
VOUT SENSE-
VR READY
PHASE FAULT
VR HOT
VR FAN