5V to 3.3V 1.2A DC-DC Converter with 200mS Vout Hold-up Time Circuit Reference Design


Design files


The PMP4494 is a 5V to 3.3V 1.2A DC-DC converter with a Vout hold-up circuit. The synchronous buck converter LM20242 is used in the design to provide high efficiency for the system voltage. A boost converter TPS61170 boosts an auxiliary rail from 10V up to 20V to provide the backup voltage. A supply voltage supervisor TLV809 monitors the system voltage and switches the supply to the backup voltage once the system voltage falls below the threshold voltage. Along with the boost circuit, the hold-up capacitance is significantly reduced while still meeting the 200mS hold-up time specification.

  • Main power supply 5V to 3.3V 1.2A output synchronous buck
  • Back-up power supply  boost up from 10Vin to 20V hold-up voltage
  • Minimum 200ms hold-up time for 3.3V
  • Bus voltage monitor and switch
  • Size: 73.5mm x 50mm x 10mm
Output voltage options PMP4494.1 PMP4494.2
Vin (Min) (V) 5 10
Vin (Max) (V) 20 10
Vout (Nom) (V) 3.3 20
Iout (Max) (A) 1.2 .1
Output Power (W) 3.96 2
Isolated/Non-Isolated Non-Isolated Non-Isolated
Input Type DC DC
Topology Buck- Synchronous Boost- Integrated Switch
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A fully assembled board has been developed for testing and performance validation only, and is not available for sale.

Design files & products

Design files

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Technical documentation

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Type Title Date
* Test report PMP4494 Test Results Sep. 29, 2016

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