Smart Ideal Diodes Protect Car Battery Front-Ends (Download)
If the battery terminals in a car are reverse-connected during a jump start, vehicle maintenance, or repair, the components in the electronics control unit (ECU) may be damaged if they can’t handle this fault condition. On top of that, during normal operation, the car battery voltage isn’t constant—the input voltage (VIN) can even be negative under several transient tests regulated by the EMC standards, such as ISO 7637 and ISO 16750. These fluctuations mean that front-end protection is necessary.
Schottky diodes and P-channel MOSFETs (PFETs) are widely used in automotive power-system designs for reverse-battery protection and automotive electrical transient protection. However, these conventional solutions have significant power dissipation, which reduces thermal efficiency and makes it more difficult for designers to meet the system’s cost and space requirements.