IR35211 datasheet(12/58 Pages) IRF

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Dual Output Digital Multi-Phase Controller

IR35211

July 24, 2014 | V1.00

GENERAL DESCRIPTION

The IR35211 is a flexible, dual-loop, digital multiphase

PWM buck controller optimized to convert a 12V input

supply to the core voltage required by Intel and AMD

high performance microprocessors and DDR memory.

It is easily configurable for 1-3 phase operation on

Loop #1 and 0-1 phase operation on Loop #2.

The unique partitioning of analog and digital circuits

within the IR35211 provides the user with easy

configuration capability while maintaining the required

accuracy and performance. Access to on-chip Multiple

Time Programming memory (MTP) to store the

IR35211 configuration parameters enables power

supply designers to optimize their designs without

changing external components.

The IR35211 controls two independent output

voltages. Each voltage is controlled in an identical

fashion, so that the user can configure and optimize

each control loop individually. Unless otherwise

described, the following functions are performed on

the IR35211 on each control loop independently.

OPERATING MODES

The IR35211 can be used for Intel VR12/12.5, AMD

SVI1/SVI2, DDR Memory and GPU designs without

significant changes to the external components (Bill of

Materials). The required mode is selected in MTP and

the pin-out, VID table and relevant functions are

automatically configured. This greatly reduces time-to-

market and eliminates the need to manage and

inventory 6 different PWM controllers.

DIGITAL CONTROLLER & PWM

A linear Proportional-Integral-Derivative (PID) digital

controller provides the loop compensation for system

regulation. The digitized error voltage from the high-

speed voltage error ADC is processed by the digital

compensator. The digital PWM generator uses the

outputs of the PID and the phase current balance

control signals to determine the pulse width for each

phase on each loop. The PWM generator has enough

resolution to ensure that there are no limit cycles. The

compensator coefficients are user configurable to

enable optimized system response. The compen-

sation algorithm uses a PID with two additional

programmable poles. This provides the digital

equivalent of a Type III analog compensator.

ADAPTIVE TRANSIENT ALGORITHM (ATA)

Dynamic load step-up and load step-down transients

require fast system response to maintain the output

voltage within specification limits. This is achieved by

a unique adaptive non-linear digital transient control

loop based on a proprietary algorithm.

MULTIPLE TIME PROGRAMMING MEMORY

The multiple time programming memory (MTP) stores

the device configuration. At power-up, MTP contents

are transferred to operating registers for access

during device operation. MTP allows customization

during both design and high-volume manufacturing.

MTP integrity is verified by cyclic redundancy code

(CRC) checking on each power up. The controller will

not start in the event of a CRC error.

The IR35211 offers up to 8 writes to configure basic

device parameters such as frequency, fault operation

characteristics, and boot voltage. This represents a

significant size and component saving compared to

traditional analog methods. The following pseudo-

code illustrates how to write the MTP:

# write data

Set MTP Command Register = WRITE,

Line Pointer = An unused line

Poll MTP Command Register until Operation = IDLE.

# verify data was written correctly

Issue a READ Command; then poll OTP Operation Register

till Operation = IDLE

Verify that the Read Succeeded

INTERNAL OSCILLATOR

The IR35211 has a single 96MHz internal oscillator

that generates all the internal system clock

frequencies required for proper device function.

The oscillator frequency is factory trimmed for

precision and has extremely low jitter (Figure 4) even

in light-load mode (Figure 5). The single internal

oscillator is used to set the same switching frequency

on each loop.

IR35211 Datasheet(PDF) 12 Page - International Rectifier

IR35211 Datasheet(HTML) 12 Page - International Rectifier

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