In-vehicle systems like Advanced Driver Assistance Systems (ADAS), In-Vehicle Infotainment (IVI) and battery management systems make driving safer and greener. They also put new demands on power management, requiring high-efficiency, low-noise supplies that can withstand voltage fluctuations. Nexperia’s tracking LDOs deliver precise, stable outputs that track input voltages. Meeting stringent automotive standards, they ensure reliable operation in any conditions.
Nexperia's new NEX91207-Q100 and NEX91x30-Q100 power ICs are voltage-tracking low dropout regulators (LDOs) that meet the AEC-Q100 standard. Ideal for battery-powered automotive applications, they enable reliable and efficient power solutions that are easy to design.
What is a tracking LDO and where to use one?
A tracking LDO is a specialized type of linear regulator that responds dynamically to a reference voltage (typically an externally provided input signal). Where a standard LDO gives a fixed output voltage, a tracking LDO ensures the output voltage remains in sync with the input reference – either maintaining a pre-defined ratio or a fixed offset. They are widely used in scenarios that require synchronized power rails along with low noise and high reliability. for examples:
Synchronizing voltages across multiple power rails such as in electronic control units (ECUs), ADAS and IVI systems
- Precise voltage matching prevents power mismatches between modules
- Improved system stability through proper synchronization, especially critical in safety-related applications like braking systems or autonomous driving modules
Low-noise power supplies for sensitive systems such as radar, cameras and communication modules
- Reduce power supply noise by minimizing ripple and electromagnetic interference
- Enhance signal integrity, which is crucial in systems like RF modules, LiDAR and high-precision sensors where noise can degrade performance
Dynamic voltage tracking for adaptive systems
- Real-time voltage adjustment by following input voltage changes, ensuring components operate within optimal conditions
- Precise voltage tracking to support load-dependent systems such as power steering, adaptive lighting, and dynamic suspension
Simplifying power management design in multi-voltage systems
- Reduce the number of voltage regulators needed
- Ensure consistent performance with fewer components to improve system reliability and cost
Powering automotive off-board sensors
Power supplies for automotive off-board sensors and small-current off-board modules require special attention, particularly regarding protection and output accuracy. Power often travels through long cables from the main boar. These cables can be prone to damage in the harsh automotive environment, resulting in short-to-ground or short-to-battery conditions on the power supply output. Robust protection mechanisms are essential to protect on-board components.
Maintaining a minimal voltage-tracking tolerance between the sensors’ power supply and the power supply for the microcontroller / ADC is also essential. In addition, achieving ultra-low voltage tracking accuracy is key to ensuring high-quality data acquisition.
A voltage-tracking LDO is an ideal solution for powering these off-board loads. They provide comprehensive protection features – including short-to-ground, short-to-battery, overload, and thermal protection – while ensuring ultra-accurate output voltage tracking for optimal performance.
Managing thermal performance
Thermal performance is a critical concern for any LDO that is directly connected to a vehicle’s battery. Automotive batteries typically output between 9 V and 16 V. The LDO must step this down to 5 V, 3.3 V or even lower to power components such as the microcontroller, CAN bus and other logic devices. Hence the voltage drop across the LDO can easily be 10 V or more. For a 100-mA load, the LDO can be dissipating more than 1 W. For higher loads, a single LDO may not be able to handle the large power dissipation effectively.
An effective solution for such a challenge is to use multiple LDOs in parallel. The figure below shows an example of this topology featuring the NEX90230-Q100 and the NEX91630-Q100. The NEX90530-Q100 is a 300-mA low quiescent current (IQ) LDO, while the NEX91630-Q100 is a 300-mA voltage-tracking LDO. This configuration can support loads up to 600 mA, effectively distributing power dissipation and improving thermal performance.
High-side switch
Certain automotive applications require a high-side switch with reverse current protection. The NEX91207-Q100 can function as a high-side switch that offers not just reverse polarity protection but also current-limit protection, thermal shutdown and output short-to-battery protection. Switching is controlled via the EN and ADJ pin, when the device is configured as a high-side switch configuration in conjunction with a voltage-tracking LDO.
