TPS62130A-Q1_016 Datasheet, PDF (13/37 Pages) Texas Instruments – 3-V to 17-V 3-A Step-Down Converter with DCS-Control

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TPS62130A-Q1, TPS62133A-Q1, TPS6213013A-Q1
SLVSCC2B – MAY 2014 – REVISED NOVEMBER 2016
10 Application and Implementation
10.1 Application Information
TPS62130xA-Q1 are synchronous switch mode step-down converters, able to convert a 3V to 17V input voltage
into a lower, 0.9V to 6V, output voltage, providing up to 3A load current. The following section gives guidance on
choosing external components to complete the power supply design. Application Curves are included for the
typical application shown here.
10.2 Typical Application
space
10.2.1 TPS62130A-Q1 Point-Of-Load Step Down Converter
12V
10uF
PVIN
SW
0.1uF
AVIN
VOS
3.3nF
EN
PG
TPS62130A-Q1
SS/TR
FB
DEF
AGND
LOG
PGND
2.2 µH
3.3V / 3A
100k
1.21M
22uF
383k
Copyright © 2016, Texas Instruments Incorporated
Figure 9. Typical Schematic for 3.3 V Step-Down Converter
10.2.1.1 Design Requirements
The step-down converter design can be adapted to different output voltage and load current needs by choosing
external components appropriate. The following design procedure is adequate for whole V_IN, V_OUT and load
current range of TPS62130A-Q1. Using Table 2, the design procedure needs minimum effort.
10.2.1.2 Detailed Design Procedure
10.2.1.2.1 Programming The Output Voltage
The TPS6213xA-Q1 can be programmed for output voltages from 0.9V to 6V by using a resistive divider from
VOUT to AGND. The voltage at the FB pin is regulated to 800mV. The value of the output voltage is set by the
selection of the resistive divider from Equation 6 (see Figure 9). It is recommended to choose resistor values
which allow a current of at least 2uA, meaning the value of R2 shouldn't exceed 400kΩ. Lower resistor values
are recommended for highest accuracy and most robust design. For applications requiring lowest current
consumption, the use of fixed output voltage versions is recommended.
space
R =R
1
2
ççèæ
V
OUT
V
REF
- 1_{÷÷øö}
(6)
space
In case the FB pin gets opened, the device clamps the output voltage at the VOS pin internally to about 7.4V.
10.2.1.2.2 External Component Selection
The external components have to fulfill the needs of the application, but also the stability criteria of the device's
control loop. The TPS6213xA-Q1 is optimized to work within a range of external components. The LC output
filter's inductance and capacitance must be considered together, creating a double pole, responsible for the
corner frequency of the converter (see Output Filter And Loop Stability). Table 2 can be used to simplify the
output filter component selection.
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