| 摘要 |
An amplifier for use in a mobile phone for supplying a signal (Io) to a load (ZL) comprises a first transistor (T1) having a first main terminal coupled to a reference terminal (GND), a control terminal, and a second main terminal for supplying the signal (Io) to the load (ZL), and sensing means for determining the value of the signal (I0). The sensing means comprises a second transistor (T2) having a first main terminal coupled to the first main terminal of the first transistor (T1), a control terminal coupled to the control terminal of the first transistor (T1), and a second main terminal for supplying a further signal (IF) which is a representation of the signal (Io). The amplifier comprises detection means (DMNS) for supplying a DC-component (IDC2) of the further signal (IF). The detection means (DMNS) comprises a resistor (R) coupled between a power supply terminal (VDD) and the second main terminal of the second transistor (T2), and a capacitor (C) coupled between the second main terminal of the second transistor (T2) and the reference terminal (GND) or the power supply terminal (VDD). The DC-component of the signal (I0) is proportional to the signal (I0) and is thus also proportional to the power supplied to the load (ZL). Since the further signal (IF) is a representation of the signal (I0) supplied to the load (ZL), the DC-component (IDC2) of the further signal (IF) is a measure for the power supplied to the load (ZL).This measure can be used to monitor the amount of power supplied to the load (ZL) and possibly to regulate the power to a desired level.
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