SLVU944B October   2015  – October 2020 TPS7H1101-SP

 

  1.   Trademarks
  2. 1Introduction
    1. 1.1 Related Documentation
  3. 2Description
  4. 3Test Setup
    1. 3.1 Equipment
      1. 3.1.1 Power Supplies
      2. 3.1.2 Load Number 1
      3. 3.1.3 Meters
      4. 3.1.4 Oscilloscope
    2. 3.2 Bench Test Setup Conditions
      1. 3.2.1 Headers Description and Jumper Placement
      2. 3.2.2 Testing
    3. 3.3 Power-Up Procedure
      1. 3.3.1  IOUT and VOUT Measurements
      2. 3.3.2  Output Current Limiting
      3. 3.3.3  High-Side Current Sense
      4. 3.3.4  Current Foldback
      5. 3.3.5  Power Good
      6. 3.3.6  Dropout Voltage
      7. 3.3.7  Transient Response
      8. 3.3.8  Current Sharing
      9. 3.3.9  Soft-Start
      10. 3.3.10 Enable and Disable
      11. 3.3.11 Turn-Off
  5. 4Board Layout
    1. 4.1 EVM Layout Flexibility
  6. 5Schematic and Bill of Materials
  7.   Revision History

3.3.2 Output Current Limiting

A resistor value R30 connected from PCL pin to GND determines the output current limit set point based on Equation 2.

Maximum programmable current limit is 3800 mA.

Equation 2. GUID-20200930-CA0I-9XPK-XMTM-RPV5MPVBGXDD-low.gif

Where VREF = 0.605 V, Icl = programmable current limit (A), CSR = Current sense ratio (typical value = 52000).

CSR between Ics pin and IOUT can be measured as shown in Figure 3-2.

See Figure 3-3 for device Iload vs PCL pin current ranges.

  • Make sure all power supplies in workstation are OFF.
  • Connect VIN(+) to J19 & V(GND) to J24 and set it to 2.3 V.
  • Set VOUT to 1.8V. (R27 = 19.8 kΩ and R28 = 10 kΩ)
  • Connect load as previously instructed, set it to zero load.
  • Increase Iload (steps of 0.100 A are suggested) until Vload starts to drop.
  • Current limit trip point < 3.8 A.
GUID-5C3C25AC-44F6-446D-8593-5EF03874A049-low.gifFigure 3-2 IOUT (A) vs IPCL (uA)
GUID-76D63CC2-FE20-4374-B86B-2107999260DA-low.gif Figure 3-3 IOUT (A) vs IPCL (A) across CSR range