SLUSCC7C July 2016 – June 2018 TPS546C23
The devices sense the average output current using an internal sense FET as shown in Figure 32. A sense FET conducts a scaled-down version of the power-stage current. Sampling this current in the middle of the low-side drive signal determines the average output current. This architecture achieves excellent current monitoring and better overcurrent threshold accuracy than the current sensing of a DC-resistance (DCR) inductor with minimal temperature variation and no dependence on power loss in a higher DCR inductor. Use the IOUT_CAL_OFFSET command to improve current sensing and overcurrent accuracy by removing systematic errors related to board layout after assembly. The devices continually digitize the sensed output current, and average it to reduce measurement noise. The devices then store the current value in the read-only register, READ_IOUT, which enables output-current telemetry.