ZHCSLA3A May 2020 – December 2020 LM7481-Q1
PRODUCTION DATA
- 1 特性
- 2 应用
- 3 说明
- 4 Revision History
- 5 Pin Configuration and Functions
- 6 Specifications
- 7 Parameter Measurement Information
- 8 Detailed Description
-
9 Application and Implementation
- 9.1 Application Information
- 9.2
Typical 12-V Reverse Battery Protection Application
- 9.2.1 Design Requirements for 12-V Battery Protection
- 9.2.2 Automotive Reverse Battery Protection
- 9.2.3 Input Transient Protection: ISO 7637-2 Pulse 1
- 9.2.4 AC Super Imposed Input Rectification: ISO 16750-2 and LV124 E-06
- 9.2.5 Input Micro-Short Protection: LV124 E-10
- 9.2.6 Detailed Design Procedure
- 9.2.7 MOSFET Selection: Blocking MOSFET Q1
- 9.2.8 MOSFET Selection: Hot-Swap MOSFET Q2
- 9.2.9 TVS selection
- 9.2.10 Application Curves
- 9.3 Do's and Don'ts
- 10Power Supply Recommendations
- 11Layout
- 12Device and Documentation Support
- 13Mechanical, Packaging, and Orderable Information
9.2.3 Input Transient Protection: ISO 7637-2 Pulse 1
ISO 7637-2 Pulse 1 specifies negative transient immunity of electronic modules connected in parallel with an inductive load when the battery is disconnected. A typical pulse 1 specified in ISO 7637-2 starts with battery disconnection where supply voltage collapses to 0 V followed by –150 V 2 ms applied with a source impedance of 10 Ω at a slew rate of 1 µs on the supply input. LM74810-Q1 blocks reverse current and prevents the output voltage from swinging negative, protecting the rest of the electronic circuits from damage due to negative transient voltage. MOSFET Q1 is quickly turned off within 0.5 µs by fast reverse comparator of LM74810-Q1.
A single bi-directional TVS or two uni-directional TVS are required at the input to clamp the negative transient pulse within the operating maximum voltage across cathode to anode of 85 V and does not violate the MOSFET Q1 drain-source breakdown voltage rating. ISO 7637-2 Pulse 1 performance of LM74810-Q1 is shown in Figure 9-2.
Figure 9-2 ISO 7637-2 Pulse 1