4-Switch buck-boost bi-directional DC-DC converter reference design
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Key Document


This DC-DC power converter reference design demonstrates a novel approach for battery backup applications. During normal operation, the converter works as a battery charger with CC-CV-Topping charging algorithm compatible for lithium-ion batteries. When DC bus power is lost, the converter immediately changes to backup operation to seamlessly provide power to the system. Once the DC bus power recovers, the converter automatically switches back to battery charge mode. The battery voltage can be higher or lower than DC bus voltage. Depending on the DC bus and battery voltage, the converter operates as either a synchronize buck or a synchronize boost converter in which only two switches are switching, switching loss is reduced and high effieciency is achieved. Only when DC bus and battery voltage are close to each other, then the converter operates as a buck-boost converter.

  • Multi-mode control to reduce switching loss and achieve high efficiency
  • Built-in battery charging CC-CV topping algorithm compatible for lithium-ion and lithium-polymer battery
  • Ultra-fast changeover from charging to backup supply mode enables seamless power transfer during power failure
  • DC-bus voltage can be higher or lower than battery voltage
  • Battery over voltage and over current protection, DC bus over voltage protection

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Design Files

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(Output Voltage 1)
Vin (Min) (V)35
Vin (Max) (V)55
Vout (Nom) (V)38
Iout (Max) (A)2
Output Power (W)76
Input TypeDC
TopologyBuck Boost- 4 Switch

TI Devices (5)

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Part Number Name Product Family Sample & Buy Design Kits & Evaluation Modules
OPA2211A  1.1nV/rtHz Noise, Low Power, Precision Operational Amplifier  Operational amplifiers (op amps)  Sample & Buy View Design Kits & Evaluation Modules
TLV1117  800-mA, 15-V, linear voltage regulator  Power management  Sample & Buy View Design Kits & Evaluation Modules
UCC27211A  4-A, 120-V half bridge gate driver with 8-V UVLO and negative voltage handling  Gate drivers  Sample & Buy Not Available
UCC3813-1  Economy low power BICMOS 1MHz current mode PWM with 9.4V/7.4V UVLO and 50% duty cycle, 0C to 70C  Offline & isolated DC/DC controllers & converters  Sample & Buy Not Available
UCD3138  Highly Integrated Digital Controller for Isolated Power with 3 Feedback Loops and 8 DPWM Outputs  Digital power ICs  Sample & Buy View Design Kits & Evaluation Modules

CAD/CAE symbols

Part # Package | Pins CAD File (.bxl) STEP Model (.stp)
OPA2211A Download Download
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TLV1117 Download Download
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UCC27211A Download
UCC3813-1 Download Download
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UCD3138 Download
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Technical documentation

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User guide (1)
Title Type Size (KB) Date
PDF 734 12 Dec 2018
Design files (6)
Title Type Size (KB) Date
ZIP 679 12 Dec 2018
ZIP 1503 12 Dec 2018
PDF 1520 12 Dec 2018
PDF 281 12 Dec 2018
PDF 105 12 Dec 2018
PDF 276 12 Dec 2018
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