SNVSCN2 September 2024 TPS37100-Q1
ADVANCE INFORMATION
The primary advantage of this application is being able to directly monitor a voltage on an automotive battery with the SENSE input.
Voltage rail monitoring is done by connecting the SENSE input to a external resistor ladder then to the battery rail. The TPS37100-Q1 that is being used in this example is an adjustable voltage variant where the monitored threshold voltage has to be set externally. Word of caution, the TVS protection diodes must be chosen such that the transient voltages on the monitored rails do not exceed the absolute max limit listed in Section 6.1. Adjustable threshold variants do not offer reverse polarity protection on the SENSE pin.
To use this configuration, the specific voltage threshold variation of the device must be chosen according to the application. In this configuration, the TPS37100Z91DDYYRQ1 is used and has the parameters and features listed in Table 4-1.
The 40V undervoltage threshold is set by R1 and R2. Assuming R2 = 2kΩ, and R1 can be calculated as R1 = 98kΩ.
The AOUT pin requires a 0.1µF stability capacitor. When operating at 48V the AOUT = 1.6V which pairs well with a 3 or 3.3V ADC of a MCU.
OUT A and OUT B can be connected to different loads. Example, OUT A be connected to the the enable of a wide VIN DC/DC converter while OUT B can be connected to a MCU GPIO.