Hi Everyone,
Please let me know about resistor located between SW node and drain of LS FET in fig.24 on TPS40195 datasheet.
I found the explanation for this Rsw in datasheet of TPS40060 and understood that Rsw prevent the negative voltage on SW
node during dead time. But I could not understand that why the negative voltage could affect the operation of the
controller, "especially at low input voltages".
So can you explain about this?
It will be appreciated if you share some documentation that exlpain about this.
[Explanation from TPS40060 datasheet]
The SW node of the converter will be negative during the dead time when both the upper and lower MOSFETs
are off. The magnitude of this negative voltage is dependent on the lower MOSFET body diode and the output
current which flows during this dead time. This negative voltage could affect the operation of the controller,
especially at low input voltages.
Therefore, a 10-Ω resistor must be placed between the lower MOSFET drain and pin 12 (SW) of the controller as
shown in Figure 14 as RSW.
Best Regards,
Sonoki / Japan Disty
