SLUSFP1B April   2025  – November 2025 UCC34141-Q1

ADVANCE INFORMATION  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison
  6. 5 Pin Configuration and Functions
  7. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Insulation Specifications
    6. 6.6 Electrical Characteristics
    7. 6.7 Safety-Related Certifications
    8. 6.8 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Power Stage Operation
        1. 7.3.1.1 VDD-COM Voltage Regulation
        2. 7.3.1.2 COM-VEE Voltage Regulation
        3. 7.3.1.3 COM-VEE Output Capability
      2. 7.3.2 Output Voltage Soft Start
      3. 7.3.3 ENA and Power-Good
      4. 7.3.4 Protection Functions
        1. 7.3.4.1 Input Undervoltage Lockout
        2. 7.3.4.2 Input Overvoltage Lockout
        3. 7.3.4.3 Output Undervoltage Protection
        4. 7.3.4.4 Output Overvoltage Protection
        5. 7.3.4.5 Over-Temperature Protection
        6. 7.3.4.6 BSW Pin Faults Protection
    4. 7.4 Device Functional Modes
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 VDD-COM Voltage Regulation
        2. 8.2.2.2 COM-VEE Voltage Regulation and Single Output Configuration
    3. 8.3 System Examples
    4. 8.4 Power Supply Recommendations
    5. 8.5 Layout
      1. 8.5.1 Layout Guidelines
      2. 8.5.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Third-Party Products Disclaimer
    2. 9.2 Documentation Support
      1. 9.2.1 Related Documentation
    3. 9.3 Receiving Notification of Documentation Updates
    4. 9.4 Support Resources
    5. 9.5 Trademarks
    6. 9.6 Electrostatic Discharge Caution
    7. 9.7 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information
    1. 11.1 Packaging Information
    2. 11.2 Tape and Reel Information
    3. 11.3 Mechanical Data

7.3.1.2 COM-VEE Voltage Regulation

An internal buck-boost converter generates the regulated negative VEE voltage. The buck-boost converter operation is determined by the sensed VEE voltage on FBVEE pin. With an internal 90k resistor and a 4.5V reference voltage, VEE voltage can be programed and regulated between -2V to -8V.

The buck-boost converter is controlled by an integrated hysteresis voltage feedback loop for COM-to-VEE voltage regulation and an integrated current control loop for cycle-to-cycle current limit. When FBVEE voltage stays below the turn-off threshold, the buck-boost converter operates with peak current mode control. The inductor current increases at the beginning of a switching cycle until it reaches the peak current limit, then returns to zero. In normal operation, the converter operates in boundary conduction mode, but can enter continuous conduction mode during start-up. As the peak current of the buck-boost is limited to less than ILIM, the chosen inductor must have a saturation current above ILIM. As shown in the Electrical Characteristics table, the peak current limit, ILIM, is implemented with a feedforward control based on VDD voltage, so that the maximum inductor current will not exceed ILIM, considering the overshoot due to the control loop delay at different VDD voltages. A higher VDD voltage leads to a bigger overshoot, and thus results in a lower ILIM value for compensation. The recommended inductor selection is between 3.0μH and 10.0μH. The typical switching frequency is fSW_VEE under the conditions listed in the Electrical Characteristics table.

After the FBVEE voltage reaches the turn-off threshold, the buck-boost converter turns off. After the FBVEE voltage drops below the turn-on threshold due to the load current, the buck-boost converter is turned on again. With the accurate voltage reference and hysteresis control, the VEE output voltage can be regulated with ≤5% accuracy.

UCC34141-Q1 COM-VEE Voltage Regulation Functional Block Diagram Figure 7-4 COM-VEE Voltage Regulation Functional Block Diagram
UCC34141-Q1 Concept of COM-VEE Regulation SchemeFigure 7-5 Concept of COM-VEE Regulation Scheme