[FAQ] Automotive 48V Rail Monitoring

Texas Instruments has wide-vin voltage supervisor that can be powered off of the battery rail and monitor either the battery rail or the step-down voltage after a DC/DC or LDO. 

Please find a demonstration of discrete solutions use multiple components (e.g., comparators, resistors, capacitors, voltage references, logic gates) to achieve the desired voltage monitoring, timing, and reset functions. As it can be seen in below, the discrete approach takes a lot space when you need more features. 

The first advantage of a supervisor is the accuracy. External components can introduce errors due to:

• Component tolerances: Resistors, capacitors, and other components have manufacturing tolerances that can affect measurement accuracy.
• Temperature drift: External components can drift with temperature, affecting accuracy.
• Noise pickup: External components can pick up noise from the environment or other parts of the circuit, impacting accuracy.
• PCB layout issues: Parasitic capacitance, inductance, and resistance in the PCB layout can also affect accuracy.

A supervisor IC minimizes these issues by integrating components, providing a more accurate and reliable solution.

Second, external components also impact the FIT rate since each of these components introduces a potential point of failure.

Integrated IC solutions incorporate all the necessary circuitry on a single piece of silicon.

The interconnections are internal to the chip, not subject to external factors like loose connections or faulty soldering, and the manufacturing process is highly controlled and reliable. 

For monitoring the 48V rail, TI recommends using TPS37100-Q1 for automotive applications

Best,

Sila Atalar