SLVUCK7A november   2022  – july 2023 TPSF12C1 , TPSF12C1-Q1

 

  1.   1
  2.   Description
  3.   Get Started
  4.   Features
  5.   Applications
  6.   6
  7. 1Evaluation Module Overview
    1. 1.1 Introduction
    2. 1.2 Kit Contents
    3. 1.3 Specifications
    4. 1.4 Device Information
  8. 2Hardware
    1. 2.1 EVM Description
    2. 2.2 Setup
      1. 2.2.1 High-Voltage Testing
      2. 2.2.2 EVM Connections
      3. 2.2.3 Low-Voltage Testing
    3. 2.3 Header Information
    4. 2.4 EVM Performance Validation
    5. 2.5 AEF Design Flow
      1. 2.5.1 AEF Circuit Optimization and Debug
  9. 3Implementation Results
    1. 3.1 EMI Performance
    2. 3.2 Thermal Performance
    3. 3.3 Surge Immunity
    4. 3.4 SENSE and INJ Voltages
    5. 3.5 Insertion Loss
  10. 4Hardware Design Files
    1. 4.1 Schematic
    2. 4.2 Bill of Materials
    3. 4.3 PCB Layout
      1. 4.3.1 Assembly Drawings
      2. 4.3.2 Multi-Layer Stackup
  11. 5Compliance Information
    1. 5.1 Compliance and Certifications
  12. 6Additional Information
    1.     Trademarks
  13. 7Related Documentation
    1. 7.1 Supplemental Content
  14. 8Revision History

1.4 Device Information

CM filters for both commercial (Class A) and residential (Class B) environments typically have limited Y-capacitance due to touch-current safety requirements and thus require large-sized CM chokes to achieve the requisite attenuation. This ultimately results in filter designs with bulky, heavy and expensive passive components. The deployment of active filter circuits enable more compact filters for next-generation power conversion systems.

Figure 3-2 presents typical schematics of equivalent single-phase passive and active filter designs. Terminals designated L, N and PE refer to Live, Neutral and Protective Earth, respectively. Comparing the passive and active circuits in Figure 3-2, the CM inductance of chokes LCM1 and LCM2 each reduces by a factor of four to six times by virtue of the higher effective Y-capacitance with the TPSF12C1 circuit.

GUID-20230714-SS0I-VD03-TPVM-PMMFZTFTNXZK-low.svg Figure 1-1 Passive and Active Filter Schematics

The AEF circuit uses a capacitive multiplier circuit in place of the two Y-capacitors normally placed between the CM chokes in a conventional two-stage passive filter design – see CY5 and CY6 in Figure 3-2. The TPSF12C1 senses the high-frequency CM disturbance on the two power lines using a set of Y-rated sense capacitors and injects a noise-canceling current back into the power lines using a Y-rated inject capacitor.

The X-capacitors placed between the two CM chokes provides a low-impedance path between the power lines from a CM standpoint, typically up to low-MHz frequencies. This allows current injection onto one power line (neutral in this case) using only one inject capacitor.

The advantages of AEF with the TPSF12C1 summarize as:

  1. Simple filter structure – with wide operating frequency range and high stability margins.
  2. Reduced CM choke size – for lower volume, weight and cost. This also enables much less copper loss and better high-frequency performance due to lower choke self-parasitics and higher self-resonant frequency.
  3. No additional magnetic components for sensing or injection – the TPSF12C1 instead uses Y-rated sense and inject capacitors with minimal impact to peak touch current (measured according to IEC 60990).
  4. Enhanced safety – the TPSF12C1 is a low-voltage device referenced to chassis ground.
  5. Standalone IC implementation – enables flexible placement of the AEF circuit near the filter components.
  6. Surge immunity – the TPSF12C1 is robust to line voltage surges (with an appropriate TVS diode installed at the low-voltage side of the inject capacitor). This helps to meet surge specifications such as IEC 61000-4-5.