2 Design 1: Automotive Reverse Battery Protection with Overvoltage, Undervoltage and Overcurrent Protection with Fault Output

A typical application circuit of LM749x0-Q1 configured in common-drain topology to provide reverse battery protection with overvoltage protection is shown in Figure 2-1

Figure 2-1 Typical Application Circuit for 12-V Reverse Battery Protection Solution

LM749x0-Q1 DGATE drives an ideal diode FET Q1 while HGATE drives load disconnect FET Q2. Ideal diode FET provides protection against system events such as input reverse battery connection, reverse current blocking during automotive transients such as ISO7637-2 Pulse 1, input short interruption events (LV124 E-10) and AC ripple on the battery line (ISO16750-2, LV124 E-06).

Load disconnect FET Q2 provides powepath cut-off functionality in case of input undervoltage, overvoltage and output short circuit and overload conditions. LM749x0-Q1 offers fully adjustable undervoltage, overvoltage, overcurrent and short circuit thresholds to ensure device offers robust performance against various automotive EMC transients. For more details on the design process, refer to LM749x0-Q1 device data sheet.

Figure 2-2 to Figure 2-5 shows some of the key performance plots of LM749x0-Q1 used as back to back FET driver for input powerpath protection.

Figure 2-2 Performance During Output Short-Circuit Event

Figure 2-4 Performance During Input Microshort Testing – 100-μs Input Short Duration

Figure 2-3 Performance During Input Overvoltage Event (HGATE Cut-Off)

Figure 2-5 Performance During Input Reverse Voltage Hot-Plug