Texas Instruments TPS6100 EVM Series, Руководство пользователя

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Layout Considerations
3-3
Layout
3.3 Layout Considerations
The basic components of a boost converter topology (as shown in Figure 3–1)
are placed on the top side of the EVM. These are the components which carry
the high currents. The ground plane is divided into two parts that are connected
to the ground pin of the device. The ground plane on the top side carries the
inductor current and the load current back to the ground terminal of the power
supply. The ground plane on the bottom side of the EVM is for connecting the
sensitive parts to ground. These are the compensation network and the volt-
age divider for the low-battery function and for fixing the output voltage on the
adjustable version. It is very important to keep noisy and high current traces
away from sensitive lines or to separate them by using additional ground
traces between them, otherwise instability or oscillation can occur. The resis-
tive divider for fixing the output voltage should be placed as close as possible
to the FB pin.
Since the device has a high switching frequency of 500 kHz and large peak
currents, the layout is an extemely important part of the design. All power com-
ponents like the input and output capacitors, the inductor, the diode, and the
device should be kept as close together as possible. The traces should be kept
short, wide, and direct.
Figure 3–1. Topology of a Boost Converter Stage
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+
V
REF
L1
D1
C2 C1
V
I
V
O
IC1