9 Application and Implementation

Note

Information in the following applications sections is not part of the TI component specification,

and TI does not warrant its accuracy or completeness. TI’s customers are responsible for

determining suitability of components for their purposes, as well as validating and testing their design

implementation to confirm system functionality.

9.1 Application Information

LM74810 controls two N-channel power MOSFETs with DGATE used to control diode MOSFET to emulate

an ideal diode and HGATE controlling second MOSFET for power path cut-off when disabled or during an

overvoltage protection. HGATE controlled MOSFET can be used to clamp the output during overvoltage or load

dump conditions. LM74810 can be placed into low quiescent current mode using EN/UVLO, where both DGATE

and HGATE are turned OFF.

9.2 Typical 12-V Reverse Battery Protection Application

A typical application circuit of LM74810 configured to provide reverse battery protection with overvoltage

protection is shown in Figure 9-1.

GND

DGATE

A

HGATE

OUT

C

EN/UVLO

VOUT1

LM74810

CAP

VS

ON OFF

Q1

Q2

D1

SW

R2

R1

OV

VSNS

R3

BATT_MON

CIN

CLOAD

CVS

CCAP

SMBJ33CA

47 µF

0.1µF

0.1µF

0.1µF

R4

CdVdT

VBATT

90.9k

9.09k

3.48k

100

10nF

VOUT2 (ALWAYS ON)

Figure 9-1. Typical Application Circuit for 12-V Reverse Battery Protection and Overvoltage Protection

9.2.1 Design Requirements for 12-V Battery Protection

The system design requirements are listed in Table 9-1.

Table 9-1. Design Parameters - 12-V Reverse Battery Protection and Overvoltage Protection

DESIGN PARAMETER

EXAMPLE VALUE

Operating Input Voltage Range

12-V battery, 12-V nominal with 3.2-V Cold Crank and 35-V Load

Dump

Output Power

200 W

Output Current Range

12-A Nominal, 18-A maximum

Input Capacitance

0.1-µF minimum

Output Capacitance

0.1-µF minimum, (optional hold-up capacitor 470 µF)

Overvoltage Cut-off

37.0 V, output cut-off >37.0 V

Battery Monitor Ratio

8:1

9.2.2 Automotive Reverse Battery Protection

The LM74810 feature two separate gate control and driver outputs i.e DGATE and HGATE to drive back to

back N-channel MOSFETs. This enables LM74810 to provide comprehensive immunity with robust system

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SNOSDD9 – DECEMBER 2022

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