Theory of Operation: Controller 3-37
3.2.2.1.2 External Regulators: SW_1.875, SW_1.4, SW_3.6
The controller board contains three TPS62050 regulators in order to regulate voltages of 1.85 V, 1.4
V, and 3.6 V. The TPS62050 is a synchronous step-down adjustable regulator. The switching
regulator is capable of sourcing 800 mA. Its output can be adjusted by using a voltage divider tied to
the feedback pin. The regulators are powered from SW_B+. Figure 3-26 is the schematic for the
VCC_SW_1.4 regulator. Figure 3-26 illustrates the supporting circuitry for the TPS62050.
Figure 3-26. VCC_SW_1.4 Regulator
3.2.2.1.3 External Switcher 5
The controller board uses an external TI regulator (TPS62110, U6505) to regulate to 5.4 V. The
TPS62110 is a 1.5 A capable synchronous step down converter. The output is adjusted using a
voltage divider to the feedback pin. The regulator is software enabled through a GPO on MAKO. The
regulator is powered from SW_B+. Figure 3-27 illustrates the SW5 circuitry.
Figure 3-27. SW5 Circuit
EXTERNAL SWITCHER 1.4V
VCC_1.55
DNP
10UF
4.7UF
C6586C6584
470PF
DNP
270
R6571
DNP
C6589
82PF
C6588
R6568
VCC_SW_1.4
301K
C6582
L6505
6.8PF
10UH
SW1V4_FB
U6507
TPS62050
DNP
SW_FILT_B+
VCC_SW1.4_VIN
R6555
R6554
R6558
C6572
R6552
R6547
C6570
R6548
C6569
DNP
0
10UF
DNP
DNP
0
270
82PF
470PF
0
165K
100K
EN
PG
VIN
FB
GND
LBI
SYNC
PGND
SW
LBO
1
7
9
10
4
26
3
5
8
SWITCHER 5
C6565
VCC_SW_5
2.2UF
180NH
L6503
C6567C6566
L6504
10UH
10UF
10UF
SW_B+
100K
R6545
SW5_VOUT_UNFILT
2
TPS62110
4
14
6
8
3
5
15
16
1
13
7
12
11
10
17
9
U6505
EN
FB
LBI
SYNC
VIN1
VINA
GND1
GND2
PGND1
PGND2
AGND
LBO
SW1
PG
VIN2
CTGND
SW2
475KR6540
10PFC6562
DNP
R6538
8.2K
C6559
R6534
0
R6533
R6537
121K
0
1UF
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