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Digital Power-Supply Controller/Monitor with PMBus Interface

Complete Control/Monitoring of Any Power Supply with PMBus Interface

Product Details

Key Features

Applications/Uses

Simplified Block Diagram

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Key Features

  • PMBus Interface for Programming, Monitoring, Sequencing Up and Down, and Accurate Output-Voltage Control
  • Controls Output Voltage with 0.2% Accuracy for Line, Load, and Temperature Variations
  • Output Voltage, Output Current, and Temperature Monitoring with Adjustable Monitor Rate
  • Current Measurement with 2.6% Accuracy
  • Programmable Soft-Start and Soft-Stop Ramp Rates
  • Controls Up to 26 Power Supplies with Hardwired Address Pins and Up to 127 POLs with Software Addressing
  • Compatible with REFIN and FB Terminals of POL Power Supplies
  • Protection for POL Against Overvoltage, Undervoltage, Overcurrent, Negative Current and Overtemperature Faults with No Action, Latch and Retry (Hiccup) Options
  • Open-Drain Active-Low FLT Signal for Fault Detection
  • Master-Slave Clocking Option Eliminates External Clock Requirement and Provides Accurate Timing Reference
  • External EEPROM Interface for Auto-Programming on Power-Up

Applications/Uses

  • DC-DC Modules and POLs
  • High-Reliability Infrastructure Equipment
  • Servers
  • Telecom Networking

Description

The MAX8688 fully integrated digital power-supply controller and monitor IC works with any existing POL (point-of-load) power supply to provide complete digital programmability. By interfacing to the reference input, feedback node, and output enable, the MAX8688 takes control of the POL to provide functions such as perfect tracking, sequencing, margining, and dynamic adjustment of the output voltage.

The MAX8688 offers an accurate 12-bit analog-to-digital converter (ADC) accompanied with two differential amplifiers for accurately monitoring both voltage and current. An integrated 12-bit digital-to-analog converter (DAC) is also available to margin power supplies as well as dynamically adjust the output voltage with 0.2% accuracy over temperature using this closed-loop system. An internal temperature sensor provides an additional level of system monitoring.

The user-programmable registers provide flexible and accurate control of time events such as a delay time and transition period, monitoring for overvoltage and undervoltage, overcurrent, reverse-current, overtemperature fault and warning handling. The closed-loop operation is also programmable to make sure the MAX8688 works with any existing POL to provide superior regulation accuracy and accurate margining.

The MAX8688 operates using a PMBus™-compliant communication protocol. The device is programmed using this protocol or simply with the use of a free graphic-user interface (GUI) available from the Maxim website that significantly reduces development time. Once the configuration is complete, the results can be saved into an EEPROM or loaded onto the part through the PMBus at power-up. This allows remote configuration of any POL using the MAX8688, replacing expensive recalls or field service. Module current sharing is also supported, since accurate current measurement and fine resolution voltage control are available. The MAX8688 can be programmed with up to 127 distinct addresses to support large systems. The MAX8688 is offered in a space-saving, 24-pin, lead-free 4mm x 4mm TQFN package.

Simplified Block Diagram

MAX8688: Typical Operating Circuit MAX8688: Typical Operating Circuit Zoom icon

Technical Docs

Support & Training

Search our knowledge base for answers to your technical questions.

Filtered Search

Our dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal .