Radio-frequency integrated circuit for a radio-frequency wireless transmitter-receiver with reduced influence by radio-frequency power leakage

• US 6,308,047 B1
• Filed: 02/03/1999
• Issued: 10/23/2001
• Est. Priority Date: 08/05/1996
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Maemura, Kosei, Yamamoto, Kazuya
• Primary Examiner(s): Le, Thanh Cong
• Assistant Examiner(s): Nguyen, Thuan T.
• Application Number:
  US09/243,467
• Time in Patent Office: 993 Days
• Field of Search: 455/257, 455/258, 455/259, 455/262, 455/252.1, 455/251.1, 455/73, 455/78, 455/80, 455/75
• US Class Current: 455/73
• CPC Class Codes: H03G 3/30 in amplifiers having semiconductor devices
• CPC Class Codes: H04B 1/48 in circuits for connecting transmitter and receiver to a common transmission path, e.g. by energy of transmitter H04B1/46 takes precedence

Abstract

In an RF front end portion for processing a radio-frequency signal in a portable telephone, a low pass filter allowing passing of only a signal in a frequency band lower than a radio-frequency signal component band is arranged between a circuit processing a high power signal and a control circuit controlling operation of the radio-frequency signal processing circuit. The radio-frequency signal processing circuit is a transmission/reception multiplexing circuit transferring a transmission signal of the portable telephone to an antenna or receiving a reception signal from the antenna, and the control circuit is a transmission/reception control circuit determining an operation mode of the transmission/reception multiplexing switch. Alternatively, the radio-frequency signal processing circuit includes a power amplifier amplifying a signal to be transmitted, and a gate voltage control circuit generating gate bias voltage controlling a gain of the power amplifier. The influence of a radio-frequency leakage component leaking from a gate of the field effect transistor can be suppressed. In the case of the transmission/reception multiplexing switch, handing power can be improved, and an increase in power consumption and occupied area of the control circuit can be suppressed. In the case of the power amplifier, the gate bias voltage can be held stably, and the power amplification can be performed accurately. In the portable telephone, the RF front end portion processing the radio-frequency signal can be provided in a chip occupying a small area.

Claims

1. A radio-frequency integrated circuit comprising:

a substrate;

a radio-frequency processing circuit including

a first field effect transistor, receiving a radio-frequency input signal within a frequency band, and transferring a signal corresponding to the radio-frequency input signal, and

a transmission/reception multiplexing switch having a transmission mode for transferring from a transmission signal input node the signal corresponding to the radio-frequency input signal to a transmission/reception node, coupled to an antenna, via a second field effect transistor, and a reception node for transferring a radio-frequency signal applied to said transmission/reception node from the antenna to a reception signal output node via a third field effect transistor;

a control voltage generating circuit applying an operation control voltage to a gate of said first field effect transistor through a control voltage path different from a transmission path of the radio-frequency input signal and including a transmission/reception control circuit for applying a control voltage for turning on and off the second and third field effect transistors in accordance with an operation mode, said radio-frequency processing circuit and said control voltage generating circuit being integrated on said substrate; and

a low pass filter for removing a signal in the frequency band of the radio-frequency input signal and connected in the control voltage path.

2. The radio-frequency integrated circuit according to claim 1, wherein

said radio-frequency processing circuit includes a power amplifier amplifying the radio-frequency input signal in said first field effect transistor, and

said control voltage generating circuit includes a gate voltage control circuit applying a bias voltage to said gate of said first field effect transistor for determining gain of said power amplifier.

3. The radio-frequency integrated circuit according to claim 2, wherein said power amplifier includes said first field effect transistor, said first field effect transistor having a gate, a resistance element connected between the gate of said first field effect transistor and a bias voltage input node, and a capacitance element connected between said bias voltage input node and a reference voltage source line, said bias voltage input node being connected to said low pass filter.

4. The radio-frequency integrated circuit according to claim 1, including an RF front end integrated circuit comprising said radio-frequency processing circuit, said control voltage generating circuit, and said low pass filter, for processing a signal in a frequency band of a carrier wave of transmission and reception signals for a portable telephone.

5. A radio-frequency integrated circuit including

a semiconductor chip;

a transmission/reception multiplexing switch circuit having a transmission signal input node, a reception signal output node, and a control signal input node separate from said transmission signal input node and said reception signal output node, and operating in accordance with a control signal applied to said control signal input node in either a transmission mode for transmitting a transmission signal applied to said transmission signal input node or a reception mode for receiving and sending an incoming signal to said reception signal output node;

a control circuit generating the control signal applied to the control signal input node of said transmission/reception multiplexing switch circuit in response to an operation mode instructing signal, said transmission/reception multiplexing switch circuit and said control circuit being integrated on said semiconductor chip; and

a low pass filter passing a signal in a band lower than a frequency band of the transmission signal applied to said transmission signal input node connected between said control circuit and said control signal input node of said transmission/reception multiplexing switch circuit.

6. The radio-frequency integrated circuit according to claim 5, wherein

said transmission/reception multiplexing switch circuit includes a switch element receiving the control signal on said control signal input node through a resistance element coupling one of said transmission signal input node and reception signal output node to a transmission/reception node electrically coupled to an antenna, and

said low pass filter includes a capacitance element connected between a reference potential source and an interconnection line between a control signal output node of said control circuit and said resistance element, said resistance element functioning as a component of said low pass filter.

7. The radio-frequency integrated circuit according to claim 6, wherein

said control circuit includes means for generating a first control signal in a transmission mode and a second control signal in a reception mode;

said switch element includes

a first switching transistor turned on to couple said transmission signal input node to said transmission/reception node when the first control signal is generated,

a second switching transistor turned on to couple said transmission signal input node to a reference potential source when the second control signal is generated,

a third switching transistor turned on to transmit the signal on said transmission/reception node to said reception signal output node when the second control signal is generated, and

a fourth switching transistor turned on to transfer the signal on said reception signal output node to said reference potential source when the first control signal is generated; and

said low pass filter is arranged only in a transmission path transmitting the second control signal to a control electrode node of said second switching transistor.

8. The radio-frequency integrated circuit according to claim 6, wherein said capacitance element has a capacitance Ca, said resistance element has a resistance Ra, and

9. The radio-frequency integrated circuit according to claim 6, wherein said capacitance element has a capacitance Ca, said resistance element has a resistance Ra, and

10. The radio-frequency integrated circuit according to claim 6, wherein said low pass filter further includes a second resistance element in said interconnection line between said control signal output node of said control circuit and a connection node between said capacitance element and said interconnection line.

11. The radio-frequency integrated circuit according to claim 10, wherein said resistance element has a resistance Ra, said additional resistance element has a resistance Rb, and

12. The radio-frequency integrated circuit according to claim 6, wherein

said transmission/reception multiplexing switch element includes a second switch element receiving a second control signal through a second resistance element and coupling the other of said transmission signal input node and said reception signal output node to said transmission/reception node electrically coupled to the antenna, said control circuit generating the second control signal, and

said radio-frequency integrated circuit further comprises a second low pass filter including a capacitance element connected between a second control signal output node of said control circuit and said second resistance element, the second control signal being output from said second control signal output node, and said second resistance element functioning as a component of said second low pass filter.

13. The radio-frequency integrated circuit according to claim 6, wherein

said switch element is connected between said reception signal output node and said transmission/reception node and transmits the incoming signal applied to said transmission/reception node to said reception signal output node, and

said transmission/reception multiplexing switch circuit includes a second switch element connected between said transmission signal input node and said transmission/reception node, receiving a second control signal through a second resistance element, and transmits the transmission signal applied to said transmission signal input node to said transmission/reception node, whereby said control circuit generates a second control signal.

14. The radio-frequency integrated circuit according to claim 5, further comprising:

an amplifier for amplifying and transmitting a radio-frequency signal to said transmission signal input node;

bias voltage generator for generating a bias voltage controlling gain of said amplifier; and

a second low pass filter connected between a bias voltage output node of said bias voltage generator and a bias voltage input node of said amplifier.

15. The radio-frequency integrated circuit according to claim 14, wherein

the second low pass filter includes:

a transmission line connected between said bias voltage output node and said bias voltage input node for transmitting said bias voltage, and having a first portion smaller in width than a second portion; and

a capacitance element connected between said bias voltage output node and a reference potential source.

16. The radio-frequency integrated circuit according to claim 14, wherein

said second low pass filter includes:

a resistance element connected between said bias voltage output node and said bias voltage input node; and

a capacitance element connected between said bias voltage output node and a reference potential source.

17. A radio-frequency integrated circuit including:

a substrate;

an amplifier having a bias voltage input node and amplifying a radio-frequency signal;

a bias voltage generating circuit generating a bias voltage for controlling gain of said amplifier and applied to said bias voltage input node of said amplifier, said amplifier and said bias voltage generating circuit being integrated on said substrate; and

a low pass filter connected between said bias voltage input node of said amplifier and a bias voltage output node of said bias voltage generating circuit, said low pass filter including a transmission line connected between said bias voltage output node of said bias voltage generating circuit and said bias voltage input node of said amplifier for transmitting the bias voltage, said transmission line having first and second portions with different, respective widths, and a capacitance element connected between said bias voltage output node and a reference potential source.

18. The radio-frequency integrated circuit according to claim 17, wherein said amplifier includes a field effect transistor having a control gate node and amplifying the radio-frequency signal received on said control gate node, wherein the bias voltage generated by said bias voltage generating circuit is a negative voltage applied to said control gate node of said field effect transistor.

19. The radio-frequency integrated circuit according to claim 17, wherein said amplifier includes a field effect transistor having a gate receiving the radio-frequency signal, a resistance element connected between the gate of said field effect transistor and said bias voltage input node, and a capacitance element connected between said bias voltage input node and a reference voltage source.

20. A radio-frequency integrated circuit including:

a substrate;

an amplifier having a bias voltage input node and amplifying a radio-frequency signal;

a bias voltage generating circuit generating a bias voltage for control gain of said amplifier and applied to said bias voltage input node of said amplifier, said amplifier and said bias voltage generating circuit being integrated on said substrate; and

a low pass filter connected between said bias voltage input node of said amplifier and a bias voltage output node of said bias voltage generating circuit, said low pass filter including;

a resistance element connected between said bias voltage output node of said bias voltage generating circuit and said bias voltage input node of said amplifier; and

a capacitance element connected between said bias voltage output node and a reference potential source.

21. The radio-frequency integrated circuit according to claim 20, wherein said amplifier includes a field effect transistor having a gate receiving the radio-frequency signal, a resistance element connected between the gate of said field effect transistor and said bias voltage input node, and a capacitance element connected between said bias voltage input node and a reference voltage source.