LM7480 datasheet(20/43 Pages) TI

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10.2.1 Design Requirements for 12-V Battery Protection

The system design requirements are listed in Table 10-1.

Table 10-1. Design Parameters for 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

50 W

Output Current Range

4-A nominal, 5-A maximum

Input Capacitance

0.1-µF minimum

Output Capacitance

0.1-µF minimum (optional hold-up capacitor of 47 µF )

Overvoltage Cut-off

37 V, output cut-off > 37 V

Battery Monitor Ratio

8:1

10.2.2 Automotive Reverse Battery Protection

The LM7480 feature two separate gate control and driver outputs i.e DGATE and HGATE to drive back to back

N-channel MOSFETs. This enables LM7480 to provide comprehensive immunity with robust system protection

during various automotive transient tests as per ISO 7637-2 and ISO 16750-2 standard as well as other

automotive OEM standards. For more information, see the Automotive EMC-compliant reverse-battery protection

with ideal-diode controllers article.

LM7480 gate drive output DGATE controls MOSFET Q1 to provide reverse battery protection and true reverse

current blocking functionality. HGATE controls MOSFET Q2 to turn off the power path during input overvoltage

condition. Resistor network R1, R2 and R3 connected to OV and SW can be configured for overvoltage

protection and also for battery monitoring under normal operating conditions as well as reverse battery

conditions. Bi-directional TVS D1 clamps the automotive transient input voltages on the 12-V battery, both

positive and negative transients, to voltage levels safe for MOSFET Q1 and LM7480.

Fast reverse current blocking response and quick reverse recovery enables LM7480 to turn ON/OFF MOSFET

Q1 during AC super imposed input and provide active rectification of the AC input superimposed on DC battery

voltage. Fast reverse current blocking response of LM7480 helps to turn off MOSFET Q1 during negative

transients inputs and input micro short interruption conditions where input can fall to 0-V for short duration.

LM7480

SNOSDD8 – DECEMBER 2022

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LM7480 Datasheet(PDF) 20 Page - Texas Instruments