Adding an LDO for Increased Standby Mode Efficiency Reference Design
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Key Document


This regulation topology is designed to increase the efficiency of a DC/DC buck converter by disabling the converter during light-load operation and providing a regulated output voltage with a low-Iq LDO. During no-load or light-load conditions, the LDO allows for low-noise, low-Iq output voltage regulation while the DC/DC is disabled.  Once the load is engaged, the DC/DC converter can provide high efficiency at high load currents, thereby combining the benefits of both devices.

  • High Efficiency output regulation from no load to full load (3A)
  • Ultra-low Iq with no load regulation (<15 uA)
  • DC/DC output ripple less than 10mV peak to peak
  • LDO output noise less than 200 uV RMS, 10Hz to 100kHz
  • 3.3% Transient Droop @ 1.2V, 300mA to 3A, 1A/ms

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TI Devices (2)

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Part Number Name Product Family Sample & Buy Design Kits & Evaluation Modules
TPS54331  3.5V to 28V Input, 3A, 570kHz Step-Down Converter with Eco-mode  Step-down (buck) regulators  Sample & Buy View Design Kits & Evaluation Modules
TPS709  150-mA, 30-V, ultra-low-IQ, low-dropout voltage regulator with reverse current protection and enable  Power management  Sample & Buy View Design Kits & Evaluation Modules

CAD/CAE symbols

Part # Package | Pins CAD File (.bxl) STEP Model (.stp)
TPS54331 Download Download
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TPS709 Download

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Technical documentation

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User guide (1)
Title Type Size (KB) Date
PDF 1196 07 Jul 2015
Design files (3)
Title Type Size (KB) Date
ZIP 495 07 Jul 2015
PDF 118 07 Jul 2015
PDF 199 07 Jul 2015

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