SLUU224A May   2005  – March 2022 TPS40100

 

  1.   Trademarks
  2. 1Introduction
  3. 2Description
    1. 2.1 Applications
    2. 2.2 Features
      1. 2.2.1 Using Remote Sense (J3)
      2. 2.2.2 Simultaneous Tracking (J3)
      3. 2.2.3 Enable (SW2)
      4. 2.2.4 Margin Up/Down (J4)
      5. 2.2.5 Power Good (J1)
      6. 2.2.6 Synchronization (J1)
  4. 3Electrical Performance Specifications
  5. 4Schematic
  6. 5Test Setup
    1. 5.1 Equipment
      1. 5.1.1 Voltage Source (VIN)
      2. 5.1.2 Meters
      3. 5.1.3 Loads (LOAD1)
      4. 5.1.4 Recommended Wire Gauge
      5. 5.1.5 Other
    2. 5.2 Equipment Setup
      1. 5.2.1 Initial EVM Jumper and Switch Settings
      2. 5.2.2 Procedure
      3. 5.2.3 Start-Up and Shutdown Procedure
      4. 5.2.4 Equipment Shutdown
    3. 5.3 Other Tests
      1. 5.3.1 Adjusting Output Voltage (R1 and R3)
      2. 5.3.2 Remote Sense Test Setup
      3. 5.3.3 Voltage Tracking Test Setup
        1. 5.3.3.1 Single Unit Tracking (Charge)
        2. 5.3.3.2 Single Unit Tracking (Discharge)
      4. 5.3.4 Enable and Disable Test Setup
        1. 5.3.4.1 Power-On Enable
      5. 5.3.5 Margin Test Setup
        1. 5.3.5.1 Margin Up 5%
      6. 5.3.6 Power Good and Synchronization Test Setup
        1. 5.3.6.1 Synchronization
  7. 6TPS40100EVM Typical Performance Data and Characteristics Curves
    1. 6.1 Efficiency
    2. 6.2 Line and Load Regulation
    3. 6.3 Loop Stability
  8. 7EVM Assembly Drawings and Layout
  9. 8List of Materials
  10. 9Revision History

5.3.1 Adjusting Output Voltage (R1 and R3)

The regulated output voltage can be adjusted by changing the values of the feedback resistors, R1 and R3. R19 and R17 are located in the feedback to provide the user with positive remote sense and the ability to perform loop analysis with a frequency/gain analyzer. Resistors R12 and the parallel combination of R1 and R3 are the dominant resistors associated with setting the output voltage. The following are the equations associated for establishing the output voltage.

Equation 1. R P A R A L L E L =   R 1   × R 3 R 1 + R 3
Equation 2. V O U T =   V R E F R 12 + R 17 R P A R A L L E L + 1
Equation 3. RPARALLEL= VREFVOUT- VREF ×(R17+R12)

where

  • VVREF = 0.690 V
  • R17 = 49.9 Ω
  • R12 = 18.2 kΩ

R1//R3 can be adjusted to provide user defined output voltages. Table 5-1 contains values for R1//R3 to generate popular output voltages.

Table 5-1 Adjusting VOUT with R1/R3
VOUT R1//R3 (RPARALLEL) R1 R3
3.3 V 4.82 k 12.4 k 7.87 k
2.5 V 6.95 k 7.15 k 237 k
2.2 V 8.33 k 8.66 k 205 k
2.0 V 9.61 k 10.0 k 237 k
1.8 V 11.34 k 12.1 k 178 k
1.5 V 15.55 k 16.2 k 365 k
1.2 V 24.69 k 26.1 k 422 k