Datasheet

Vin=12V
BUCK3 Line driver
BUCK3
PUMP
(Regulates up to 2Vin-1.5
+
DUMP
adjustable 7.5-15.1V
BUCK2
BUCK1
BUCK2 I/O
BUCK1 SYS
LDOs
Always ON
PGOOD monitor
3.3V
6.5V
PGOOD
GASP monitor
GASP
TPS65250
SLVSAA3C –JUNE 2010–REVISED OCTOBER 2012 www.ti.com
TYPICAL APPLICATION CIRCUIT FOR ADSL SYSTEM AND COMPONENT SELECTION
The TPS65250 has been devised to optimize the power train of xDSL applications. Figure 29 shows a simplified
block diagram.
Figure 29. TPS65250 Main Blocks
TPS65250 has several features that improve and simplify the power stage design including a unique storage and
release circuit optimized for reduction of storage capacitance needed in dying gasp mode, as well as a low
power mode. Table 1 shows the advantages of its usage.
Table 1. Storage and Release Circuit Advantages
FEATURE ADVANTAGE
System can operate with a 12-V adapter keeping the storage features System can run with a12-V adapter instead of bulky and expensive
of a higher storage voltage. 22 V.
Storage capacitors are separated from the input supply minimizing Converters run from 12 V allowing for improved efficiency and
stresses during normal operation. performance compared to converters operating from 22 V.
Storage capacitors are charged with a controlled inrush free circuit
from the adaptor supply to a selected storage voltage as high as [2V
IN
Reduced stresses on AC adapter, reduced inrush current
- 1.5 V].
If the input voltage drops below a selected release voltage, charge
from the storage capacitors is transferred to the input stage
Controlled voltage release during dump operation
keeping the input voltage closer to release value for as long as
possible.
Storage and release circuitry is completely on chip except for the
Reduced number of parts
charge and storage capacitors.
Circuit features a flag signal issued to indicate that the dump stage
Self-contained pump and dump signaling is in process. Can be used to signal the host processor to start a
load reduction process.
Enable pins allow for immediate start-up, for accurate sequencing
Enable input pins for start-up and sequencing
add a capacitor to the enable pins.
16 Submit Documentation Feedback Copyright © 2010–2012, Texas Instruments Incorporated
Product Folder Links: TPS65250