TPS65279V Datasheet, PDF (8/43 Pages) Texas Instruments – 4.5-V TO 18-V INPUT VOLTAGE, 5-A/5-A DUAL SYNCHRONOUS STEP-DOWN CONVERTER WITH I2C CONTROLLED VID AND CURRENT SHARING

TPS65279V
SLVSBW1A – FEBRUARY 2013 – REVISED JUNE 2013
www.ti.com
NAME
EN1, EN2
PGND2
PVIN2
ADDR
MODE
V7V
VIN
PVIN1
PGND1
SDA
SCL
FB1
VOUT1
BST1
LX1
SS1
COMP1
ROSC
AGND
COMP2
SS2
LX2
NO.
(HTSSOP)
1, 2
3, 4
5, 6
7
8
9
10
11, 12
13, 14
15
16
17
18
19
20, 21
22, 27
23
24
25
26
27
28, 29
TERMINAL FUNCTIONS
NO.
(QFN)
DESCRIPTION
32, 33
Enable pin. Adjust the input under-voltage lockout with two resistors.
34, 35, 36
Power ground of Buck 2, place the input capacitor’s ground pin as close
as possible to this pin.
1, 2
Power input. Input power supply to the power switches of the power
converter 2.
3
I²C address configuration pin. Connect this pin to low, high or leave it
open to select different I²C slave address.
4
Operation mode control pin. Connect this pin to ground to choose forced
PWM mode without current sharing; leave the pin open for pulse skipping
mode (PSM) operation at light load condition; connect this pin to V7V to
choose forced PWM mode and current sharing with paralleling two bucks.
5
Internal low-drop linear regulator (LDO) output to power internal driver
and control circuits. Decouple this pin to power ground with a minimum
1-µF ceramic capacitor. Output regulates to typical 6.3 V for optimal
conduction on-resistances of internal power MOSFETs. In PCB design,
the power ground and analog ground should have one-point common
connection at the (-) terminal of V7V bypass capacitor. If VIN is lower
than 6.3 V, V7V will be slightly lower than VIN.
6
Power supply of the internal LDO and controllers
7, 8
Power input. Input power supply to the power switches of the power
converter 1.
9, 10, 11
12
13
Power ground of Buck 1, place the input capacitor’s ground pin as close
as possible to this pin.
I²C interface data pin
I²C interface clock pin
14
Feedback sensing pin for the external feedback resistors in Buck 1.
Before I²C controlled VID selection is enabled, an external resistor divider
connects to this pin to pre-set the output voltage.
15
Buck 1 output voltage sensing pin; When I²C controlled VID selection is
enabled, output voltage can be programmed from 0.68 V to 1.95 V with
10-mV steps. In current sharing application, this pin is the output voltage
sensing pin.
16
Add a bootstrap capacitor between BST1 and LX1. The voltage on this
capacitor carries the gate drive voltage for the high-side MOSFET.
17, 18, 19 Switching node of Buck 1
20, 25
Soft-start and voltage tracking in Buck 1. An external capacitor connected
to this pin sets the internal voltage reference rise time. Since the voltage
on this pin overrides the internal reference, it can be used for tracking and
sequencing. In current sharing application, this pin serves as the soft-start
pin.
21
Error amplifier output and loop compensation pin for Buck 1. Connect
frequency compensation to this pin; In current sharing application, this pin
serves as the compensation pin.
22
Oscillator frequency programmable pin. Connect an external resistor to
set the switching frequency. When connected to an external clock, the
internal oscillator synchronizes to the external clock.
23
Analog ground of the controllers
24
Error amplifier output and loop compensation pin for Buck 2. Connect
frequency compensation to this pin. In current sharing application,
connect this pin to ground.
25
Soft-start and voltage tracking in Buck 2. An external capacitor connected
to this pin sets the internal voltage reference rise time. Since the voltage
on this pin overrides the internal reference, it can be used for tracking and
power sequencing. In current sharing application, connect this pin to
ground.
26, 27, 28 Switching nodes
8
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