15W Dual Isolated Output Bias Power Supply with 4mW Zero Standby Power Consumption Reference Design


Design files


This reference design is a 15-W bias power supply with two isolated outputs (12 V/1.125A and 3.3 V/0.3A) and a total standby power consumption of 4 mW under a 220-V AC input. The controller uses primary-side regulation (PSR) and detects a wake-up signal from the UCC24650 secondary-side voltage-droop monitor for improved transient response to large load steps. This reference design demonstrates how the UCC28730 can provide ultra-low standby power without sacrificing start-up time or output transient response with an internal 700-V start-up switch, dynamically controlled operating states, and a tailored modulation profile. The UCC28730 uses frequency modulation, peak primary current modulation, valley switching, and valley skipping in its control algorithm to maximize efficiency over the entire operating range.

  • Enables zero-power standby consumption:
    • 3.1 mW at 115-V AC Input
    • 4.2 mW at 220-V AC Input
  • Average efficiency >84%, exceeds DoE VI and CoC tier 2 specifications
  • Primary-side regulation (PSR) eliminates optocoupler and increase reliability of bias power supply
  • Resonant-ring valley-switching operation for highest overall efficiency
  • Universal input voltage range (85V to 270V AC) to address customer needs across all regions
  • Dual isolated outputs of 12V and 3.3V is suitable for most industry applications
  • Frequency-dither to ease EMI compliance
Output voltage options TIDA-01560.1 TIDA-01560.2
Vin (Min) (V) 85 85
Vin (Max) (V) 264 264
Vout (Nom) (V) 12 3.3
Iout (Max) (A) 1.125 .3
Output Power (W) 13.5 .99
Isolated/Non-Isolated Isolated Isolated
Input Type AC AC
Topology Flyback- Non Sync Flyback- Non Sync
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A fully assembled board has been developed for testing and performance validation only, and is not available for sale.

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Design files

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TIDUDS3.PDF (1098 K)

Reference design overview and verified performance test data


Detailed schematic diagram for design layout and components


Complete listing of design components, reference designators, and manufacturers/part numbers


Detailed overview of design layout for component placement


Files used for 3D models or 2D drawings of IC components


Design file that contains information on physical board layer of design PCB


PCB layer plot file used for generating PCB design layout


Includes TI products in the design and potential alternatives.

AC/DC & DC/DC controllers (external FET)

UCC24650200-V wake-up monitor for fast transient primary-side regulation

Data sheet: PDF | HTML
AC/DC & DC/DC controllers (external FET)

UCC28730Zero standby PSR flyback controller with CVCC and wake-up monitoring

Data sheet: PDF | HTML
Linear & low-dropout (LDO) regulators

TLV743P300-mA low-IQ low-dropout (LDO) voltage regulator with enable

Data sheet: PDF | HTML

Technical documentation

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Type Title Date
* Design guide 15W Dual Isolated Output Bias Power Supply With 4mW Zero Standby Power Consumpt Mar. 23, 2018
Technical article Get smarter about ‘zero’ standby power in your next appliance design PDF | HTML Aug. 27, 2018

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