PT7712 Datasheet, PDF (5/8 Pages) Texas Instruments – 20-A Programmable Integrated Switching Regulator

Application Notes
PT7710 Series, PT7744, PT7745
Increasing the Output of the PT7710 Family of
ISRs with a 20-A Compatible Current Booster
The output of PT7710 family of regulators (PT7711–
PT7716) can produce an additional 20-A output using a
compatible current booster module. Two booster modules
are available. They are the PT7744 and PT7745, which
are compatible with regulators that operate off 3.3-V
or 5-V input buses respectively. Refer to Table 2-1 for
regulator/booster compatiblity.
The booster modules are controlled directly by the regu-
lator and effectively add a parallel output stage. They
operate sychronously, to provide a low-noise solution.
Up to two booster modules can be connected to a PT771x
regulator. Each booster added increases the regulator’s
output current by 20A, for up to 60A of output current.
Current boosters are not stand-alone products, and can
only operate with a regulator. They are housed in the same
package as the regulator, and share the same mechanical
outline. Except for an increase in output current, the
overall performance of a regulator/booster combination
is identical to that of a stand-alone regulator. For more
details refer to the applicable regulator specifications.
Table 2-1; Booster Compatibility
Regulator
PT7711
PT7712
PT7713
PT7714
PT7715
PT7716
P7744 Booster
(3.3V Input Bus)
•
•
•
•
PT7745 Booster
(5V Input Bus)
•
•
Notes:
1. Each booster requires the same amount of input and
output capacitance as recommended for a stand-alone
regulator. Consult the individual data sheet of the
applicable regulator, and the related application note
regarding capacitor selection for this product family.
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 20ADC at full output load.
3. The pin-out of the current booster modules include a
number pins identified, “No Connect” (see Table 2-2).
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 2-2; Booster Pin-Out Information
Pin Function
1 No Connect
2 No Connect
3 No Connect
4 No Connect
5 No Connect
6 No Connect
7 Vin
8 Vin
9 V_in
Pin Function
10 V_in
11 Vin
12 No Connect
13 GND
14 GND
15 GND
16 GND
17 GND
18 GND
Pin Function
19 GND
20 Vout
21 Vout
22 Vout
23 V_out
24 Vout
25 Vout
26 No Connect
27 Sync In
Figure 1-1; Current Booster Application Schematic
VID0
VID1
VID2
VID3
VID4
V_IN
PROGRAMMING PINS
REMOTE SENSE (+)
L_IN
1µH
+
C _IN
64321
VID4 - VID0
26
SNS(+)
7-11 _VIN
PT771x
V_O ^20-25
Synch
STBY Out GND
5
27 13-19
SNS(-)
12
+
C_OUT
GND
STBY*
REMOTE SENSE (–)
L_IN
1µH
+
C _IN
7-11 _VIN
27
Synch In
PT7744/45
Booster
GND
13-19
V_O ^20-25
+
C_OUT
V_OUT
LOAD
GND
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