Datasheet

SLVA037A
Designing a USB Power Distribution System Using the TPS2014 and TPS2015 Power Distribution Switches
17
Each test was configured as follows:
• The power supply was connected with 1-meter leads and adjusted for a test board output of
4.75 V.
• The test circuits had no bulk capacitance added. Only the required 120-µF per port output
capacitors were implemented.
• Each test was implemented with only two output ports. The collective sum of capacitance is
increased by 120
µF for each output port. The more ports a hub has, the higher the total
capacitance and the lower the droop voltage.
The 10-
µF and 44-Ω transient load was placed as close as possible to the output in order to
minimize interconnect resistance and inductance (see Figure 11). This causes the highest
possible transient current and the most voltage droop.
Figure 11. Non-Ganged Transient Load Test Circuit