Amplification circuit

Abstract

An amplifier circuit includes a first signal terminal, a second signal terminal, and a path circuit. The first signal terminal can receive radio frequency (RF) signals. The second signal terminal can output an output signal corresponding to the RF signal. The path circuit includes an RF switching element, an electrical overload circuit, a low-pass filter element, a high-pass filter element, and an amplifier circuit. The RF switching element can selectively receive the RF signal. A first terminal of the RF switching element is coupled to the first signal terminal. The low-pass filter element and the electrical overload circuit are connected in series between the second terminal of the RF switching element and a reference voltage terminal to form a conduction path to discharge charge when an electrical overload event occurs. The high-pass filter element is connected in parallel with the electrical overload circuit. The amplifier circuit amplifies the RF signal.

Claims

1. An amplifier circuit, comprising: a first signal terminal for receiving a radio frequency (RF) signal; a second signal terminal for outputting an output signal corresponding to the RF signal; and a first path circuit, comprising: a first RF switching element for selectively receiving the RF signal, including a first terminal and a second terminal, the first terminal being coupled to the first signal terminal; an electrical over-stress circuit; and a low-pass filter element connected in series with the electrical over-stress circuit between the second terminal of the first RF switching element and a first reference voltage terminal to form a low-frequency conduction path for dissipating charge through the low-frequency conduction path when an electrical over-stress event occurs, the low-pass filter element including a first terminal coupled to the electrical over-stress circuit and a second terminal coupled to the first reference voltage terminal; A high-pass filter element is connected in parallel with the electrical over-stress circuit. The high-pass filter element includes a first terminal coupled to the second terminal of the first RF switching element and a second terminal coupled to the first terminal of the low-pass filter element. An amplifier circuit is also included for amplifying the RF signal. The amplifier circuit includes a first terminal coupled to the second terminal of the first RF switching element and a second terminal coupled to the second signal terminal. The high-pass filter element and the low-pass filter element form a specific frequency notch path between the second terminal of the first RF switch element and the first reference voltage terminal at a specific frequency.

2. The amplifier circuit as claimed in claim 1, further comprising an antenna coupled to the first signal terminal.

3. The amplifier circuit as claimed in claim 1, wherein the amplifier circuit is a low-noise amplifier.

4. The amplifier circuit as claimed in claim 3 further includes a second path circuit, wherein the second path circuit includes a second radio frequency switching element, wherein, during normal operation, one of the first radio frequency switching element and the second radio frequency switching element is turned on.

5. The amplifier circuit as claimed in claim 4, wherein the second path circuit further includes a power amplifier.

6. The amplifier circuit as claimed in claim 5, further comprising a third path circuit, wherein the third path circuit includes a third radio frequency switching element, wherein, during normal operation, one of the first radio frequency switching element, the second radio frequency switching element, and the third radio frequency switching element is turned on.

7. The amplifier circuit as claimed in claim 1, wherein the low-pass filter element includes an inductor.

8. The amplifier circuit as claimed in claim 1 or 7, wherein the high-pass filter element includes a capacitor.

9. The amplifier circuit of claim 1, wherein the electrical over-stress circuit includes a first diode and a second diode, the first diode being configured in a forward orientation and the second diode being configured in a reverse orientation, the first diode and the second diode being configured in parallel and connected in series between the second terminal of the first RF switching element and the low-pass filter element.

10. An amplifier circuit, comprising: a first signal terminal for receiving a radio frequency (RF) signal; a second signal terminal for outputting an output signal corresponding to the RF signal; and a first path circuit, comprising: a first RF switching element for selectively receiving the RF signal, including a first terminal and a second terminal, the first terminal being coupled to the first signal terminal; an electrical overstress circuit, including a transistor and a first resistor, wherein the transistor includes a first terminal, a second terminal and a control terminal, the first terminal being coupled to the second terminal of the first RF switching element, the second terminal being coupled to a first terminal of a low-pass filter element, and the control terminal being coupled to one terminal of the first resistor; a low-pass filter element, connected in series with the electrical overstress circuit between the second terminal of the first RF switching element and a first reference voltage terminal, for forming a low-frequency conduction path to discharge charge through the low-frequency conduction path when an electrical overstress event occurs; A high-pass filter element connected in parallel with the electrical over-stress circuit; and an amplifier circuit for amplifying the radio frequency signal, the amplifier circuit including a first terminal coupled to the second terminal of the first radio frequency switching element, and a second terminal coupled to the second signal terminal.

11. The amplifier circuit of claim 10, wherein the other end of the first resistor is coupled to the second end of the transistor, and the transistor is a bipolar transistor or a field-effect transistor.

12. The amplifier circuit of claim 10, wherein the electrical over-stress circuit includes a second resistor and the transistor is a field-effect transistor, wherein one end of the second resistor is coupled to one end of the field-effect transistor.

13. The amplifier circuit of claim 12, wherein the other end of the first resistor and the other end of the second resistor are respectively coupled to a bias circuit, the bias circuit providing a control bias to the other end of the first resistor and a substrate bias to the other end of the second resistor.

14. The amplifier circuit of claim 1, wherein the amplifier circuit includes an amplifying transistor, the control terminal of the amplifying transistor being coupled to the second terminal of the first radio frequency switching element, the second terminal of the amplifying transistor being coupled to the first reference voltage terminal, and the first terminal of the amplifying transistor being coupled to the second signal terminal.

15. The amplifier circuit as claimed in claim 14, wherein the amplifier circuit further includes an input capacitor, and the control terminal of the amplifying transistor is coupled to the second terminal of the first radio frequency switching element through the input capacitor.

16. An amplifier circuit, comprising: a first signal terminal for receiving a radio frequency (RF) signal; a second signal terminal for outputting an output signal corresponding to the RF signal; and a first path circuit, comprising: a first RF switching element for selectively receiving the RF signal, including a first terminal and a second terminal, the first terminal being coupled to the first signal terminal; an electrical over-stress circuit; and a low-pass filter element connected in series with the electrical over-stress circuit between the second terminal of the first RF switching element and a first reference voltage terminal, for forming a low-frequency conduction path to discharge charge through the low-frequency conduction path when an electrical over-stress event occurs; A high-pass filter element is connected in parallel with the electrical over-stress circuit; and an amplifier circuit for amplifying the radio frequency signal, the amplifier circuit including a first terminal coupled to the second terminal of the first radio frequency switching element, a second terminal coupled to the second signal terminal, an amplifying transistor, and a clamping circuit, wherein the amplifying transistor includes a first terminal, a control terminal and a second terminal, the control terminal of the amplifying transistor is coupled to the second terminal of the first radio frequency switching element, the second terminal of the amplifying transistor is coupled to the first reference voltage terminal, the first terminal of the amplifying transistor is coupled to the second signal terminal, and the clamping circuit is connected in series between the control terminal and the first reference voltage terminal of the amplifying transistor.

17. The amplifier circuit as claimed in claim 1, wherein the electrical over-stress circuit and the low-pass filter element can form a clamping circuit at low frequencies.

18. The amplifier circuit of claim 1, wherein the first path circuit further includes a radio frequency venting switch element connected in series between the second terminal of the first radio frequency switch element and the first reference voltage terminal.

19. The amplifier circuit of claim 4, wherein the second path circuit further includes a radio frequency venting switch element connected in series between the second terminal of the second radio frequency switch element and the first reference voltage terminal.

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