SLVUBU5A May   2020  – December 2020 LM7481-Q1

 

  1.   Trademarks
  2. 1Introduction
    1. 1.1 Features
    2. 1.2 Applications
  3. 2Description
    1. 2.1  Input Power and Load (J1/J3 and J2/J4):
    2. 2.2  Enable Control (J5):
    3. 2.3  Over Voltage Protection (J6):
    4. 2.4  Input Voltage Monitor (J10 and VIN_MON):
    5. 2.5  Two Back-Back Connected MOSFETs (Q1/Q3 and Q2/Q4):
    6. 2.6  Output Slew Rate Control (R2 and C4):
    7. 2.7  Output Schottky Diode (D2) and LED Indication:
    8. 2.8  TVS Selection for 12-V Battery Protection:
    9. 2.9  TVS Selection for 24-V Battery Protection:
    10. 2.10 RC Input Snubber Option (R7 and C15):
    11. 2.11 Optional LC Filter at the Output (L2 and C11):
    12. 2.12 Test Points:
  4. 3Schematic
  5. 4Test Equipment Requirements
    1. 4.1 Power Supplies
    2. 4.2 Meters
    3. 4.3 Oscilloscope
    4. 4.4 Loads
  6. 5Test Setup and Results
    1. 5.1 Initial Setup
    2. 5.2 Power Up
    3. 5.3 Over Voltage Protection
    4. 5.4 Enable Control
    5. 5.5 Input Reverse Polarity
    6. 5.6 Load Transient Response
  7. 6EVM Board Layout and Bill of Materials
    1. 6.1 EVM Board Layout
    2. 6.2 Bill of Materials
  8. 7Revision History

2.12 Test Points:

Test point labeled DGATE is used for monitoring gate voltage of Q1 and HGATE is used for gate voltage of Q2. Test Point labelled VIN measures input voltage, VOUT measure output voltage. Test Point labelled VOUT_ALWAYS_ON measures the drain voltage of Q1 MOSFET. Test Points GND1, GND3 and GND4 provides access to the input GND voltage and GND2 provides access to the LM74810-Q1 GND pin.

Table 2-1 Connectors: Input and Output
Connector Description
J1 Power input connector to the positive rail of the input power supply
J3 Ground connection for the power supply
J2 Power output connector to the positive side of the load
J4 Ground connection for the load
J9 Optional Output Connection with LC filter
J8 Optional Input LC Filter connection
Table 2-2 Test Points Description
Test Points Description
VIN Input power supply to the EVM
VOUT Output from the EVM
VOUT_ALWAYS_ON Output voltage after the Ideal Diode MOSFET for connecting always ON loads
VIN_MON Input monitoring for battery inputs
DGATE Output of Ideal Diode MOSFET Gate Control
HGATE Output of Hot-Swap MOSFET Gate Control
GND1, GND 2, GND3 and GND4 Test Point for EVM Ground
Table 2-3 Jumpers and LED Description
Jumpers Description
J5 EN/UVLO Control
  • 1-2 Enables by connecting to VIN
  • 2-3 Disables by connecting to GND
J6 OVP Setting
  • 1-2 OVP set to Output Clamp (hysteretic) at 37.5 V
  • 2-3 OVP set to Input OVP Cutoff at 37.5 V
J7 Enables LED indication for output
J10 Input Voltage Sense
  • 1-2 Input Voltage Sense after Ideal Diode MOSFET
  • 2-3 Input Voltage Sense directly on input supply