Datasheet

Dynamic Voltage Positioning
+1%
-1%
PWMMode
medium/heavyload
PFMMode
lightload
Smooth
increasedload
PWMMode
medium/heavyload
PFMMode
lightload
Fastloadtransient
COMP_LOWthreshold
V
OUT_NOM
Soft Start
V
OUT
EN
95%
5%
t
Start
t
RAMP
TPS65053
TPS650531
TPS650532
www.ti.com ............................................................................................................................................. SLVS754C – MARCH 2007 – REVISED SEPTEMBER 2009
This feature reduces the voltage under/overshoots at load steps from light to heavy load and vice versa. It is
activated in Power Save Mode operation when the converter runs in PFM Mode. It provides more headroom for
both the voltage drop at a load step increase and the voltage increase at a load throw-off. This improves load
transient behavior.
At light loads, in which the converters operate in PFM Mode, the output voltage is regulated typically 1% higher
than the nominal value. In case of a load transient from light load to heavy load, the output voltage will drop until
it reaches the skip comparator low threshold set to – 1% below the nominal value and enters PWM mode. During
a load throw off from heavy load to light load, the voltage overshoot is also minimized due to active regulation
turning on the N-channel switch.
Figure 19. Dynamic Voltage Positioning
The two converters have an internal soft start circuit that limits the inrush current during start-up. During soft
start, the output voltage ramp up is controlled as shown in Figure 20 .
Figure 20. Soft Start
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