SNVSCB9A march   2023  – april 2023 TPSF12C1

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 System Characteristics
    7. 7.7 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Active EMI Filtering
        1. 8.3.1.1 Schematics
      2. 8.3.2 Capacitive Amplification
      3. 8.3.3 Integrated Line Rejection Filter
      4. 8.3.4 Compensation
      5. 8.3.5 Remote Enable
      6. 8.3.6 Supply Voltage UVLO Protection
      7. 8.3.7 Thermal Shutdown Protection
    4. 8.4 Device Functional Modes
      1. 8.4.1 Shutdown Mode
      2. 8.4.2 Active Mode
  9. 9 Applications and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 Design 1 – AEF Circuit for a High-Density 3-kW Server Rack Power Supply
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
          1. 9.2.1.2.1 Sense Capacitors
          2. 9.2.1.2.2 Inject Capacitor
          3. 9.2.1.2.3 Compensation Network
          4. 9.2.1.2.4 Injection Network
          5. 9.2.1.2.5 Surge Protection
        3. 9.2.1.3 Application Curves
    3. 9.3 Power Supply Recommendations
    4. 9.4 Layout
      1. 9.4.1 Layout Guidelines
      2. 9.4.2 Layout Example
  10. 10Device and Documentation Support
    1. 10.1 Device Support
      1. 10.1.1 Third-Party Products Disclaimer
      2. 10.1.2 Development Support
    2. 10.2 Documentation Support
      1. 10.2.1 Related Documentation
    3. 10.3 Receiving Notification of Documentation Updates
    4. 10.4 Support Resources
    5. 10.5 Trademarks
    6. 10.6 Electrostatic Discharge Caution
    7. 10.7 Glossary
  11. 11Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

9.2.1 Design 1 – AEF Circuit for a High-Density 3-kW Server Rack Power Supply

Figure 9-2 shows a schematic diagram of a 3-kW high-density server rack power supply with conventional two-stage passive EMI filter. The CM chokes and Y-capacitors provide CM filtering, whereas the leakage inductance of the CM chokes and the X-capacitors achieve DM attenuation. Similar to TI reference designs PMP23069, TIDA-010062 and PMP41006, the circuit uses a single-phase bridgeless power-factor correction (PFC) front-end. The DC/DC stage, which provides galvanic isolation and step-down voltage regulation, is a phase-shift full-bridge (PSFB) topology with fixed switching frequency. Alternatively, the DC/DC stage may be an LLC-based topology with variable switching frequency.

In this particular example, the TTPL PFC stage and isolated DC/DC stage run at fixed switching freqeuncies of 100 kHz and 200 kHz, respectively. Even though the use of GaN power switches (such as LMG3522-Q1 with top-side cooling) enables a high power density, the conventional passive EMI filter still occupies at least 20% of the overall solution size.

GUID-20221106-SS0I-SFGB-DLC9-CW3MVRPGVTTT-low.svg Figure 9-1 Simplified Circuit Schematic of a Server Rack Power Supply With a Conventional Two-Stage Input EMI Filter

Note that the DC/DC stage in particular increases the CM EMI signature based on the high dv/dt of the GaN switches, the transformer interwinding capacitance as well as the various switch-node parasitic capacitances to chassis ground.

This application example replaces the two Y-capacitors, designated as CY3 and CY4 in Figure 9-2, with a single-phase AEF circuit using the TPSF12C1. See Figure 9-3. The AEF circuit provides capacitive multiplication of the inject capacitor, which reduces the CM inductance values and thus the size, weight, and cost of the CM chokes, now designated as LCM1-AEF and LCM2-AEF. The total capacitance of the sense and inject capacitors is kept similar to that of the replaced Y-capacitors, which results in the line-frequency leakage current remaining effectively unchanged.

GUID-20221106-SS0I-XTHB-CK8K-PC9MM99FKKBW-low.svg Figure 9-2 Circuit Schematic of a Single-phase Server Power Supply With AEF Circuit Connected