SLUSF08 March   2024 TPS1213-Q1

ADVANCE INFORMATION  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
    6. 5.6 Switching Characteristics
  7. 6 Parameter Measurement Information
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Charge Pump and Gate Driver Output (VS, G1PU, G1PD, BST, SRC)
      2. 7.3.2 Capacitive Load Driving
        1. 7.3.2.1 Using Low Power Bypass FET (G2 drive) for Load Capacitor Charging
        2. 7.3.2.2 Using Main FET's (G1 drive) Gate Slew Rate Control
      3. 7.3.3 Short-Circuit Protection
        1. 7.3.3.1 Short-Circuit Protection With Auto-Retry
        2. 7.3.3.2 Short-Circuit Protection With Latch-Off
      4. 7.3.4 Device Functional Modes
        1. 7.3.4.1 State Diagram
        2. 7.3.4.2 State Transition Timing Diagram
        3. 7.3.4.3 Power Down
        4. 7.3.4.4 Shutdown Mode
        5. 7.3.4.5 Low Power Mode
        6. 7.3.4.6 Active Mode
      5. 7.3.5 Undervoltage Protection (UVLO)
      6. 7.3.6 Reverse Polarity Protection
      7. 7.3.7 Short-Circuit Protection Diagnosis (SCP_TEST)
  9. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Application Limitations
        1. 8.1.1.1 Short-Circuit Protection Delay
        2. 8.1.1.2 Short-Circuit Protection and Load wakeup Threshold
    2. 8.2 Typical Application 1: Driving Power at all times (PAAT) Loads With Automatic Load Wakeup
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
      3. 8.2.3 Application Curves
    3. 8.3 Typical Application 2: Driving Power at all times (PAAT) Loads With Automatic Load Wakeup and Output Bulk Capacitor Charging
      1. 8.3.1 Design Requirements
      2. 8.3.2 External Component Selection
      3. 8.3.3 Application Curves
    4. 8.4 TIDA-020065: Automotive Smart Fuse Reference Design driving Power at all times (PAAT) Loads With Automatic Load Wakeup, Output Bulk Capacitor Charging, Bi-directional Current Sensing and Software I2t
    5. 8.5 Power Supply Recommendations
    6. 8.6 Layout
      1. 8.6.1 Layout Guidelines
      2. 8.6.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Receiving Notification of Documentation Updates
    2. 9.2 Support Resources
    3. 9.3 Trademarks
    4. 9.4 Electrostatic Discharge Caution
    5. 9.5 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information
    1. 11.1 Tape and Reel Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • DGX|19
Thermal pad, mechanical data (Package|Pins)
Orderable Information

8.3.2 External Component Selection

By following similar design procedure as outlined in Section 8.2.2, the external component values are calculated as below:

  • CBST = 150 nF
  • RISCP = 20.2 kΩ to set 100 A as short-circuit protection threshold
  • CTMR = 3.3 nF to set 50 μs short-circuit protection delay
  • R4 and R5 are selected as 470 kΩ and 107 kΩ respectively to set VIN undervoltage lockout threshold at 6.5 V

Programming the Inrush current – R3 and CDVDT Selection

Use following equation to calculate the IINRUSH:

Equation 24. IINRUSH= COUT× VBATT_MAXTcharge

Use following equation to calculate the required Cg based on IINRUSH calculated in Equation 24.

Equation 25. Cg = CLOAD × I(G)IINRUSH

Where,

I(G) is 165 µA (typical),

To set IINRUSH at 1.76 A, Cg value is calculated to be ~ 20.6 nF.

A series resistor Rg must be used in conjunction with Cg to limit the discharge current from Cg during turn-off . The chosen value of R3 is 100 Ω and Cg is 22 nF.

Programming the Load Wakeup Threshold – RBYPASS and Q3 Selection

During normal operation, the resistor RBYPASS along with bypass FET RDSON is used to set load wakeup current threshold.

For selecting the MOSFET Q3, important electrical parameters are the maximum continuous drain current ID, the maximum drain-to-source voltage VDS(MAX), the maximum drain-to-source voltage VGS(MAX), and the drain-to-source ON resistance RDSON.

Based on the design requirements, BUK7J1R4-40H is selected and its ratings are:

  • 40-V VDS(MAX) and ±20-V VGS(MAX)

  • RDS(ON) is 1.06-mΩ typical at 10-V VGS

  • MOSFET Qg(total) is 73 nC typical

  • MOSET VGS(th) is 2.4 V min

  • MOSFET CISS is 5.4 nF typical

The recommended range of the short-circuit threshold voltage which is same as load wakeup threshold, V(SCP/LWU), extends from 30 mV to 500 mV. Values near the low threshold of 30 mV can be affected by the system noise. Values near the upper threshold of 500 mV would result in high short-circuit current threshold. To minimize both the concerns, 50 mV is selected as the short-circuit or load wakeup threshold voltage.

The V(SCP/LWU) value can also be calculated based on selected RISCP resistor by following equation:

Equation 26. V(SCP/LWU) (mV)= 2 μA × RISCP +10 mV

RBYPASS resistor value can be selected using below equation:

Equation 27. RBYPASS = V(SCP/LWU)ILWU -RDSON_BYPASS

Refer to Equation 13 in Section 8.1.1.2 section for update in equation in final revision of IC.

To set 50 mA as load wakeup threshold, RBYPASS value is calculated to be ~ 1 Ω.

The average power rating of the bypass resistor can be calculated by following equation:

Equation 28. PAVG= ILWU2× RBYPASS

The average power dissipation of RBYPASS is calculated to be ~ 0.0025 W

The peak power dissipation in the bypass resistor is given by following equation:

Equation 29. PPEAK= VBATT_MAX2RBYPASS

The peak power dissipation of RBYPASS is calculated to be ~ 256 W

The peak power dissipation time for power-up with short into LPM can be calculated based on following equation:

Equation 30. TPULSE= CISS× V(G2_GOOD) - VGS(th)I(G2) + 10 µs

where,

V(G2_GOOD) is internal threshold with 7 V (typical) value,

I(G2) is 165 μA (typical),

VGS(th) is gate to source voltage and CISS is effective input capacitance of selected bypass FET.

Based on Equation 30, TPULSE is calculated to be ~ 769 μs.

One 1-Ω, 1.5-W, 1% CRCW25121R00FKEGHP resistor is used to support both average and peak power dissipation for > TPULSE time calculated in Equation 30.

TI suggests the designer to share the entire power dissipation profile of bypass resistor with the resistor manufacturer and get their recommendation.

The peak short-circuit current in bypass path can be calculated based on following equation:

Equation 31. IPEAK_BYPASS=VIN_MAXRBYPASS

IPEAK_BYPASS is calculated to be 16-A based on RBYPASS selected in Equation 27.

TI suggest the designer to ensure that operating point (VBATT_MAX, IPEAK_BYPASS) for bypass path (Q3) is within the SOA curve for > TPULSE time calculated in Equation 30.