SLVAFH6 November   2023 LM25066 , LM5066 , LM5066I , TPS25984 , TPS25985 , TPS25990 , TPS536C9T

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2What are PSYS™ and PSYS_CRIT#™?
  6. 3Implementation of PSYS Monitor
    1. 3.1 Existing Designs
    2. 3.2 Proposed Designs
  7. 4ISYS Resistor (RISYS) and Gain (ISYS_IN_GAIN) Selection in TPS536C9T VR14 Controller
    1. 4.1 Steps to Calculate the Value of RIMON or RISYS and ISYS_IN_GAIN
    2. 4.2 Design Example
  8. 5Functional Verification of PSYS and PSYS_CRIT# in TPS536C9T VR14 Controller Using TPS25984, TPS25985, or TPS25990 eFuses as PSYS Monitor
  9. 6Extraction of Platform Current Information With Multiple PSYS Monitors Connected to the Same PSU
    1. 6.1 Designing the Non-Inverting Summing Amplifier
    2. 6.2 Design Guideline and Example
  10. 7Summary
  11. 8References

4.2 Design Example

  1. Maximum DC load current (IOUT(max)) is considered as 200 A.
  2. The circuit-breaker threshold during steady-state (IOCP) is considered to be 1.1 times IOUT(max). Hence, IOCP is set at 220 A.
  3. The maximum voltage range of the ISYS_IN input of the TPS536C9T controller is 1.8 V.
  4. As discussed in Section 4.1, VIREF is set at half of 1.8 V, 0.9 V.
  5. Using Equation 3, RIMON or RISYS is calculated to be 225 Ω with GIMON as 18.18 µA/A and VIREF as 0.9 V. The nearest value of RIMON or RISYS is 226 Ω with 0.1% tolerance and power rating of 100 mW. For noise reduction, place a 22 pF ceramic capacitor across the IMON pin and GND in the eFuses.
  6. Using Equation 6, ISYS_IN_GAIN is calculated to be 245.