Advanced Driver Assistance Systems (ADAS) helps to drive safely and alerts the driver when the system detects a risk from the surrounding object, no matter what the risk is. Increasing the ADAS system is one of the major trends in the car from 2016 to 2020. Such systems generally provide dynamic functions such as adaptive cruise control, blind spot detection, lane departure alarm, snooze monitoring, night vision and more dynamic functions. Consumers are increasingly concerned about driving safety, requiring comfortable driving, the government's traffic safety regulations are also increasing, these factors have contributed to the growth of ADAS in the car.
Most ADAS systems are at the heart of a microprocessor that handles all inputs from the various sensors in the vehicle and then further processes the input information so that information can be provided to the driver in an easily identifiable and understandable form member. In addition, this type of system is usually directly from the vehicle's main battery, the main battery of the nominal voltage of 9V to 18V, but due to voltage within the system transient, it may be up to 42V, it may also be cold in the case of low V. It is therefore clear that any DC / DC converter used must be capable of handling a wide input voltage range of 3.5V to 42V.
Many ADAS systems require 5V and 3.3V rails to power a variety of analog and digital IC components, but the processor I / O and core voltage will be in the range of less than 2V. In addition, space and calorie problems must also be considered. While it is common practice to use a high-voltage DC / DC converter to provide 5V and 3.3V rails, it is not always practical to provide a voltage rail of less than 2V with this converter because multiple single-output converters are used Causing the solution size to be too large, as well as potential heat limits. A more suitable solution is to use a single DC / DC converter that provides multiple outputs.
Multi - track DC / DC converter
Because of these limitations, Linear Technology has developed the 4-output monolithic synchronous buck converter LT8602. Its 3V to 42V input voltage range makes the device ideal for automotive applications including ADAS, since such applications must be stabilized by the lowest input voltage as low as 3V cold start and stop - Kai condition and more than 40V load bursts state. As can be seen in Figure 1, its 4-channel design incorporates two high-voltage 2.5A and 1.5A channels and two lower voltage 1.8A channels to provide four independent outputs and provides low 0.8V voltage, so that the device can drive the currently available minimum voltage microprocessor core. Its synchronous rectification topology provides up to 94% efficiency while Burst Mode runs in a no-load standby to keep the quiescent current below 30μA (all channels are connected), making the device ideal for always turning on system.
The LT8602's switching frequency can be set in the 250kHz to 2MHz range and can be synchronized in this range. The 60ns shortest turn-on time allows 16VIN to 2.0VOUT buck switching at 2MHz switching frequency on high-voltage channels. When the high voltage VOUT2 channel is fed with two low-voltage channels (VOUT3 and VOUT4), the two low-voltage channels can provide output as low as 0.8V and can be switched at 2MHz frequency to form a very compact footprint 25mm x 25mm) 4-output solution.