6-Bit Programmable 2- to 4-Phase
Synchronous Buck Controller
Selectable 2-, 3-, or 4-phase operation at up to 1 MHz
±10 mV worst-case differential sensing error over
Logic-level PWM outputs for interface to external
high power drivers
Enhanced PWM flex mode for excellent load transient
Active current balancing between all output phases
Built-in power-good/crowbar blanking supports on-the-fly
VID code changes
Digitally programmable 0.3750 V to 1.55 V output
Programmable short-circuit protection with programmable
Desktop PC power supplies for next generation
The ADP31961 is a highly efficient multiphase synchronous
buck switching regulator controller optimized for converting a
12 V main supply into the core supply voltage required by high
performance Advanced Micro Devices, Inc. (AMD) processors.
It uses an internal 6-bit DAC to read a voltage identification
(VID) code directly from the processor, which is used to set the
output voltage between 0.3750 V and 1.55 V.
This device uses a multimode PWM architecture to drive the
logic-level outputs at a programmable switching frequency that
can be optimized for VR size and efficiency. The phase
relationship of the output signals can be programmed to provide
2-, 3-, or 4-phase operation, allowing for the construction of up to
four complementary buck switching stages.
The ADP3196 supports a programmable slope function to
adjust the output voltage as a function of the load current so
that it is always optimally positioned for a system transient. This
can be disabled by connecting Pin LLSET to Pin CSREF.
1Protected by U.S. Patent Number 6,683,441; others patents pending.
FUNCTIONAL BLOCK DIAGRAM
DAC – 250mV
34 35 36 37 38 39
VID5 VID4 VID3 VID2 VID1 VID0
Figure 1. Functional Block Diagram
The ADP3196 also provides accurate and reliable short-circuit
protection, adjustable current limiting, and a delayed power-
good output that accommodates on-the-fly output voltage
changes requested by the CPU. The ADP3196 has a built-in
shunt regulator that allows the part to be connected to the 12 V
system supply through a series resistor.
The ADP3196 is specified over the extended commercial
temperature range of 0°C to +85°C and is available in a
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