Ultralow Quiescent Current Linear Regulator for Automotive Air Bags

Overview

As automobiles continue to add more electronic devices, a major challenge facing electronic control module designers is how to improve product performance within a limited power budget. Today's cars include numerous electronic systems, such as stereo and infotainment systems, wiper controls, light drive systems, and safety features such as airbags. These system requirements all rely on the car's battery for power, and designers must reduce the power consumption of each electronic system as much as possible, especially after the car is turned off and parked in the parking lot.

After the car's engine is turned off, the battery typically still needs to power multiple systems. In order to reduce the power consumption in this case, the power management module introduces several power saving modes: shutting down the microprocessor clock, shutting down the converter circuit through the enable input, these are the two most common examples. However, some devices and functions—for example, remote keyless entry (PKE) and security systems—should always remain operational, regardless of whether the power source comes from a generator or battery. Figure 1 shows a typical airbag power module.

This article describes a reference design that uses the MAX15006 / MAX15007 linear regulator to reduce automotive air bag quiescent current. In addition to ultra-low quiescent current, these devices are capable of withstanding load dumps up to 45V, making them ideal for harsh automotive operating environments. In addition, they also have functions such as low dropout voltage, wide input voltage range, thermal and short-circuit protection, enable input, etc., making them an ideal choice for automotive airbag power supply modules.

Figure 1. Typical automotive airbag power module