Solving the power supply problem

AN4304

6/20

DocID024731 Rev 1

Consid

ering a shunt of 0.05 Ω, the theoretical voltage seen at the input of the TSC103 is

150 mV. Due to the switching mode of the power supply, the provided 5 V has an

undesirable high frequency signal as shown in Figure 4: "Input pin+ voltage without

filtering". This high frequency signal may impact the functioning of the TSC103.

Figure 4: Input pin+ voltage without filtering

The power supply delivers a 5-V DC with a parasitic AC signal at 100 kHz and spikes at

high frequency (see Figure 5: "Differential voltage without filtering"). The question is how to

correctly filter the signal before treatment by the TSC103?

Figure 5: Differential voltage without filtering

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Time (µs)