5.15

Application example

Control of power amplifier in wireless infrastructure

Current sensing is important in a power amplifier application from at least three main standpoints. Firstly, from a

technical aspect, monitoring the performance of a power amplifier helps maximizing the output power allowing to

achieve a good linearity and efficiency. Secondly, by reducing the overall energy consumption of base stations,

the impact on the environment is limited as much as possible. Finally, by considering that roughly half of the total

energy of a wireless infrastructure is consumed by the power amplifier, optimizing its efficiency also allows for a

financial benefit.

The integrated comparator in the TSC200 device can be used as a protection. Effectively combined with an RF

switch as shown in Figure 50, when a higher current appears in the power amplifier, due to a current spike, the

comparator can toggle a control pin of the RF switch and cut the signal to the gate of the power amplifier to

prevent any damage. This analog path is much faster than digital processing and offers better protection.

Figure 50. TSC200 used to drive and protect a power amplifier

+

-

OUT

VIN+

Vcc

VIN-

Reference

voltage 0.6V

CMPOUT

RESET

-

+

CMPIN

GND

Vcc

Vcc

5V

R1

R2

Rp=5.1kΩ

Rs

Rr=470kΩ

Cr=0.22µF

Cd=100nF

RF Switch

Vicm

RFIN

ADC

DAC

Power Amplifier

Antenna

TSC200

TSC200, TSC201, TSC202

Application example

DS13882 - Rev 2

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