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Assembly Drawing and List of Materials
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SLUUBX3B – June 2019 – Revised November 2019
Copyright © 2019, Texas Instruments Incorporated
UCC25640EVM-020 Evaluation Module
The resulting voltage is fed to a current sense amplifier with a 200V/V gain. The amplifier output is
compared to a set reference voltage to determine when to enter or exit standby mode. Hysteresis is
implemented on the comparator using R52 and R48.
Figure 30. External Standby Circuit Current Sense Gain and Comparator
The standby circuit adjusts the output voltage set point by changing the feedback resistor divider ratio
through Q6 and R56. When in standby mode, the gate of Q6 is held low. When out of standby mode, Q6
is turned on to put R56 in parallel to R23.
Figure 31. Output Voltage Set Point Adjustment