PT7761-5V_09 Datasheet, PDF (4/9 Pages) Texas Instruments – 40-A Programmable Integrated

Application Notes
PT7761, PT7769
Increasing the PT7761 Output Current with
the PT7769 Compatible Current Booster
The PT7769 is a 40-A “Current Booster” module
for the PT7761 regulator. The booster is controlled
directly by the regulator, and effectively adds a
parallel output stage. This allows the system to run
sychronously, providing a low noise solution. Up to
three booster modules can be connected to a single
regulator. Each booster increases the available output
current by 40A. Combinations of a regulator and
booster modules can supply power for virtually any
multi-processor application.
A current booster is not a stand-alone product, and
can only operate with a regulator. It is housed in
the same package as its compatible regulator, and
shares the same mechanical outline. Except for an
increase in output current, the overall performance
of a PT7761/booster combination is identical to
that of a stand-alone regulator. Refer to the appro-
priate data sheet for the performance specifications.
Notes:
1. Each booster requires the same amount of input and
output capacitance as recommended for a stand-alone
regulator. See the Standard Application schematic and
the respective input/output filter notes in the PT7761
product data sheet. Recommendations on specific
capacitor types are also detailed in the application note,
“Capacitor Recommendations for the PT7761
Integrated Switching Regulator.”
2. The 1-µH filter choke located at the input of each
regulator and booster module (L_in) is optional for most
applications. If specified, each inductor must be sized
to handle 30ADC at full output load.
3. The pin-out of the current booster modules include a
number pins identified, “No Connect” (see Table 1).
These pins are not connected internally to the module
but must be soldered to a pad to preserve the unit’s
mechanical integrity.
4. A similar PCB footprint and trace layout between the
regulator and each booster will facilitate current sharing
between all modules.
Table 1; PT7769 Pin-Out Information
Pin Function
1 No Connect
2 No Connect
3 No Connect
4 No Connect
5 No Connect
6 No Connect
7 Sync
8 No Connect
9 Vin
10 V_in
Pin Function
11 Vin
12 V_in
13 Vin
14 Vin
15 No Connect
16 GND
17 GND
18 GND
19 GND
20 GND
Pin Function
21 GND
22 GND
23 Vout
24 Vout
25 Vout
26 V_out
27 Vout
28 Vout
29 Vout
30 V_out
31 No Connect
Current Booster Application Schematic
VID0
VID1
VID2
VID3
VID4
V_IN
GND
PROGRAMMING PINS
L_IN
1µH
+
C_IN
REMOTE SENSE (+)
54 321
VID0 - VID4
31
Sns (+)
9–14
V _IN
PT7761
23–30
V_OUT
Stby Sync GND Sns (–)
67
16–22 15
+
C _OUT
V_OUT
LOAD
GND
STBY*
REMOTE SENSE (–)
7
Synch
L_IN
9–14
V _OUT
PT7769
1µH
+
C_IN
To
Additional
Boosters
GND
16–22
23–30
V _OUT
+
C _OUT
For technical support and more information, see inside back cover or visit www.ti.com