SLUAAS4 January   2024 LM5155-Q1 , LM51551-Q1 , LM5156-Q1 , LM51561-Q1 , LM51561H-Q1 , LM5156H-Q1 , LM5157-Q1 , LM51571-Q1 , LM5158-Q1 , LM51581-Q1 , UCC28700-Q1 , UCC28730-Q1 , UCC28740-Q1 , UCC28781-Q1 , UCC28C50-Q1 , UCC28C51-Q1 , UCC28C52-Q1 , UCC28C53-Q1 , UCC28C54-Q1 , UCC28C55-Q1 , UCC28C56H-Q1 , UCC28C56L-Q1 , UCC28C57H-Q1 , UCC28C57L-Q1 , UCC28C58-Q1 , UCC28C59-Q1

 

  1.   1
  2.   Abstract
  3. 1Introduction
    1. 1.1 Low-Voltage Isolated Bias Power Supply
    2. 1.2 High-Voltage Isolated Bias Power Supply
  4. 2Pre-Regulator Requirement
    1. 2.1 Pre-Regulator at Low-Voltage Battery
      1. 2.1.1 Single Pre-Regulators Architecture
      2. 2.1.2 Multiple Pre-Regulators Architecture
    2. 2.2 Pre-Regulator From High-Voltage Battery
  5. 3Fully-Distributed Architecture
  6. 4Semi-Distributed Architecture
  7. 5Centralized Architecture
  8. 6Redundancy in Isolated Bias Power Supply Architectures
    1. 6.1 No Redundancy
    2. 6.2 Redundancy to all Devices
    3. 6.3 Redundancy to Low Side Only
    4. 6.4 Redundancy to High Side Only
  9. 7Summary
  10. 8Terminology

1.2 High-Voltage Isolated Bias Power Supply

High-voltage isolated bias power supply circuits have an HV battery as a power source in HEV and EV. As an HV battery, 400V and 800V voltage batteries are the most common in HEVs and EVs. The isolated bias supply connected to the HV battery needs to support a wider input voltage range. The need for wide input voltage range support is similar to the LV battery: SOC and load dump scenarios of the HV battery. Based on the SOC of the battery, a wider input voltage range needs to be supported. For example, commonly considered voltage ranges are 240V–450V for a 400V battery and 550V–950V for an 800V battery. However, this voltage range can be different depending on the OEM requirement.

Although the HV battery can be used as a primary source for isolated bias power supply, mostly the battery is used to provide redundancy. Flyback topology is usually selected for such a high and wide input voltage range from a technical perspective as well with respect to minimizing costs.

Table 1-2 Texas Instruments High-Voltage Isolated Bias Supply Topologies and Associated Devices
DeviceUCC28C5x-Q1UCC28700-Q1UCC28730-Q1UCC28740-Q1UCC28781-Q1
Switching TypeHard-switchedValley switchingValley switchingValley switchingZero-voltage switching (ZVS)
Feedback
Regulation(1)		Primary, Secondary (Optocoupler)PrimaryPrimarySecondary (Optocoupler)Secondary (Optocoupler)
Typical Power Levels20–100W2–50W2–50W2–50W50–150W
(1) Primary side regulation removes the optocoupler from the design.