Datasheet

+
2.2 Fm
2.2 Fm 0.1 Fm
332 kW
61.9 kW
0.01 Fm 90.9 kW
C2 C3
C4
R3
R4
CSS
RT
U1
TPS54160ADGQ
C1
0.1 Fm
L1
10 Hm
D1
B220A
C
OUT
47 F/6.3 Vm
CF
6.8 pF
RC
76.8 kW
CC
2700 pF
R1
31.6 kW
R2
10 kW
VIN
BOOT
EN
SS/TR
RT/CLK
PwPd
PWRGD
VSNS
COMP
GND
PH
8 - 18 V
3.3 V at 1.5 A
TPS54160 , TPS54160A
www.ti.com SLVSB56C –MAY 2012–REVISED FEBRUARY 2014
9 Application and Implementation
9.1 Application Information
TPS5426x devices are part of a family of non-synchronous, step-down converters with an integrated high-side
FET and 100% duty cycle capability. Idea applications are 12-V, 24-V and 48-V industrial and commercial low
power systems. Aftermarket Auto Accessories: Video, GPS, Entertainment
9.2 Typical Application
Figure 52. High Frequency, 3.3V Output Power Supply Design with Adjusted UVLO.
9.2.1 Design Requirements
This example details the design of a high frequency switching regulator design using ceramic output capacitors.
A few parameters must be known in order to start the design process. These parameters are typically determined
at the system level. For this example, we will start with the following known parameters:
Table 1. Design Parameters
DESIGN PARAMETER EXAMPLE VALUE
Output Voltage 3.3 V
Transient Response 0 to 1.5A load step ΔV
OUT
= 4%
Maximum Output Current 1.5 A
Input Voltage 12 V nom. 8 V to 18 V
Output Voltage Ripple < 33 mV
pp
Start Input Voltage (rising VIN) 7.7 V
Stop Input Voltage (falling VIN) 6.7 V
9.2.2 Detailed Design Procedures
9.2.2.1 Selecting the Switching Frequency
The first step is to decide on a switching frequency for the regulator. Typically, the user will want to choose the
highest switching frequency possible since this will produce the smallest solution size. The high switching
frequency allows for lower valued inductors and smaller output capacitors compared to a power supply that
switches at a lower frequency. The switching frequency that can be selected is limited by the minimum on-time of
the internal power switch, the input voltage and the output voltage and the frequency shift limitation.
Equation 12 and Equation 13 must be used to find the maximum switching frequency for the regulator, choose
the lower value of the two equations. Switching frequencies higher than these values will result in pulse skipping
or the lack of overcurrent protection during a short circuit.
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