SLVUBO2B April   2019  – December 2020 TPS23758

 

  1.   Trademarks
  2. 1Introduction
    1. 1.1 Features
    2. 1.2 Applications
  3. 2Electrical Specifications
  4. 3Description
  5. 4Schematic
  6. 5General Configuration and Description
    1. 5.1 Physical Access
  7. 6TPS23758EVM-080 Performance Data
    1. 6.1 Startup to PSE and DCDC Startup
    2. 6.2 Transient Response
    3. 6.3 Efficiency
    4. 6.4 Load Regulation
    5. 6.5 Recovery from VOUT Short
    6. 6.6 Slew Rate Adjust
  8. 7EVM Assembly Drawings and Layout Guidelines
    1. 7.1 PCB Drawings
    2. 7.2 Layout Guidelines
    3. 7.3 EMI Containment
  9. 8Bill of Materials
  10. 9Revision History

3 Description

The TPS23758EVM-080 enables full evaluation of the TPS23758 device. Refer to the schematic shown in Figure 4-1. Ethernet power is applied from J1 and is dropped to the bridge rectifier (D1, D2). The Power over Ethernet (PoE) transformer needed to transfer power or data is T1. The Bob Smith Terminations help balance the Ethernet cable impedance and are critical for ESD and EMI or EMC performance. The EMI or EMC filter and transient protection for the TPS23758 device are at the output of the diode bridge.

Input power can also be applied at J4 from a DC source when power at J1 is not present.

The TPS23758 (U1) PD and DC-to-DC converter circuitry is shown in Figure 4-1. R17 provides the detection signature. The switched side of the PD controller is to the right of U1. The TPS23758 RTN pin provides inrush limited turn on and charge of the bulk capacitor, C18.

The DC-to-DC converter is a high-efficiency diode rectified primary-side regulated flyback converter.

Output voltage feedback is provided with R19 and R24 on the bias winding. R16 provides a means for error injection to measure the frequency response of the converter.