6-Bit, Programmable 2-/3-/4-Phase,

Synchronous Buck Controller

ADP3191

FEATURES

Selectable 2-, 3-, or 4-phase operation at up to

1 MHz per phase

±14.5 mV worst-case differential sensing error

over temperature

Logic-level PWM outputs for interface to external

high power drivers

transient performance

Active current balancing between all output phases

Built-in power good/crowbar blanking supports on-the-fly

VID code changes

6-bit digitally programmable 0.8375 V to 1.6 V output

Programmable short circuit protection with programmable

latch-off delay

APPLICATIONS

Desktop PC power supplies for

Next-generation Intel® processors

VRM modules

Games consoles

GENERAL DESCRIPTION

The ADP3191/ADP3191A1 are highly efficient, multiphase,

synchronous buck switching regulator controllers optimized for

converting a 5 V or 12 V main supply into the core supply voltage

required by high performance Intel processors. They use 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 0.8375 V and 1.6 V. The devices use a multimode

PWM architecture to drive the logic-level outputs at a program-

mable 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 ADP3191/ADP3191A also include programmable, no-load

offset and slope functions to adjust the output voltage as a function

of the load current, so it is always optimally positioned for a

system transient. The ADP3191/ADP3191A also provide

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.

FUNCTIONAL BLOCK DIAGRAM

VCC

PRECISION

REFERENCE

SOFT

START

DELAY

OSCILLATOR

GND

ADP3191/

ADP3191A

19

28

RT

13

RAMPADJ

14

PWM2

26

8

FB

PWM3

25

PWM4

24

SW1

23

CSSUM

17

CSCOMP

18

SW2

22

SW3

21

SW4

20

CSREF

16

PWM1

VID4

1

VID3

2

VID2

3

VID1

4

VID5

6

VID0

5

FBRTN

7

VID

DAC

DAC+150mV

DAC–250mV

CSREF

EN

CURRENT

LIMIT

CIRCUIT

CROWBAR

CURRENT

LIMIT

CMP

CMP

CMP

CMP

CURRENT

BALANCING

CIRCUIT

2-/3-/4-PHASE

DRIVER LOGIC

EN

SET

RESET

RESET

RESET

RESET

27

SHUNT

REGULATOR

(ADP3191 ONLY)

UVLO

SHUTDOWN

AND BIAS

Figure 1.

The ADP3191 is a replacement for the ADP3181. A built-in

shunt regulator allows the part to be connected to the 12 V

system supply through a series resistor.

The devices are specified over the commercial temperature

range of 0°C to 85°C and are available in a 28-lead TSSOP

and a 28-lead QSOP.

Rev. 0

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