High frequency power amplifier component and radio communication system

• US 20040229579A1
• Filed: 05/13/2004
• Published: 11/18/2004
• Est. Priority Date: 05/15/2003
• Status: Active Grant

• Current Assignee: Hitachi Hybrid Network Co., Ltd. (Hitachi, Ltd.), Renesas Electronics Corporation
• Original Assignee: Hitachi Hybrid Network Co., Ltd. (Hitachi, Ltd.), Renesas Technology Corporation (Renesas Electronics Corporation)
• Inventors: Tsutsui, Takayuki, Matsushita, Kouichi, Nagamori, Hiroyuki
• Granted Patent: US 7,346,318 B2
• Time in Patent Office: Days
• US Class Current: 455/127.2
• CPC Class Codes: H03F 1/0244 Stepped control
• CPC Class Codes: H03F 2200/294 the amplifier being a low noise amplifier [LNA]
• CPC Class Codes: H03F 2200/372 Noise reduction and elimination in amplifier
• CPC Class Codes: H03F 2200/451 the amplifier being a radio frequency amplifier
• CPC Class Codes: H03F 2200/78 A comparator being used in a controlling circuit of an amplifier
• CPC Class Codes: H03F 3/189 High-frequency amplifiers, e.g. radio frequency amplifiers
• CPC Class Codes: H03F 3/24 of transmitter output stages

Abstract

In radio communication system that is able to transmit in two or more modulation modes, e.g., one modulation mode when phase shifts are performed and another modulation mode when phase shifts and amplitude shifts are performed, the disclosed invention can avoid that receiving band noise becomes so great not to conform to the GSM standards'"'"' prescription for such noise in a high voltage region of the power supply voltage, even when the output power is controlled by changing the amplitude of the input signal to the power amplifier circuitry while fixing the bias voltages to be applied to the power amplifying transistors. When the output power is controlled as above, in the modulation mode (GSM mode) when phase shifts are performed, idle currents flowing across the power amplifying transistors are regulated, depending on the power supply voltage, i.e., the idle currents are decreased when the power supply voltage is high and increased when the power supply voltage is low.

Claims

1. A high-frequency power amplifier component comprising a high-frequency power amplification circuit which comprises power amplifying transistors and is capable of operating in a first operation mode in which said power amplifying transistors amplify and output phase modulated high-frequency signals and in a second operation mode in which said power amplifying transistors amplify and output phase modulated and amplitude modulated high-frequency signals and a bias circuit which applies bias to said power amplifying transistors, said bias causing a changeover between idle currents flowing across said power amplifying transistors in said first operation mode and idle currents flowing across said power amplifying transistors in said second operation mode,

wherein said bias circuit is configured to change the idle currents flowing across said power amplifying transistors, depending on the level of power supply voltage and the level of required output power, in said first operation mode.

2. The high-frequency power amplifier component according to claim 1, wherein said high-frequency power amplification circuit comprises a plurality of power amplifying FETs, high-frequency signals to be amplified being imput to the gate terminals of said power amplifying FETs, and

wherein said bias circuit is configured to change an idle current following across a last-stage power amplifying FET, depending on the level of power supply voltage and the level of required output power, in said first operation mode.

3. The high-frequency power amplifier component according to claim 1, wherein the magnitude of the idle currents flowing across said power amplifying transistors changes stepwise, depending on the level of required output power, and said bias circuit is configured to change the idle currents flowing across said power amplifying FETs, depending on the level of power supply voltage, when the idle currents are set at the greatest level.

4. The high-frequency power amplifier component according to claim 1,

wherein said bias circuit comprises a current-voltage conversion means for converting a supplied control current into a voltage, a current adjusting circuit which adjusts the supplied control current, depending on the level of power supply voltage, by decreasing the current when the power supply voltage level is higher and increasing the current when the power supply voltage level is lower, and a switching means for routing the supplied control current to said current adjusting circuit or said current-voltage conversion means, by bypassing the current adjusting circuit, depending on which operation mode, and

wherein the voltage into which the control current has been converted by said current-voltage conversion means is applied to the gate terminal of one of said power amplifying FETs to allow the idle current flow across the power amplifying FET and said switching means is configured to be controlled to route the supplied control current to said current adjusting circuit in the first operation mode.

5. The high-frequency power amplifier component according to claim 4, wherein said switching means is configured to make a changeover by a control signal to indicate which operation mode.

6. The high-frequency power amplifier component according to claim 4, wherein said bias circuit includes a decision means for judging the magnitude of supplied control current and said switching means is configured to make a changeover, according the result of judgment made by said judging means.

7. A radio communication system comprising the high-frequency power amplifier component comprising a high-frequency power amplification circuit which comprises power amplifying transistors and is capable of operating in a first operation mode in which said power amplifying transistors amplify and output phase modulated high-frequency signals and in a second operation mode in which said power amplifying transistors amplify and output phase modulated and amplitude modulated high-frequency signals and a bias circuit which applies bias to said power amplifying transistors, said bias causing a changeover between idle currents flowing across said power amplifying transistors in said first operation mode and idle currents flowing across said power amplifying transistors in said second operation mode, wherein said bias circuit is configured to change the idle currents flowing across said power amplifying transistors, depending on the level of power supply voltage and the level of required output power, in said first operation mode, a second electronic component including a transmission/reception change-over circuit which changes over system operation between transmitting signals and receiving signals, and a third electronic component which modulates transmit signals and inputs modulated transmit signals to said high-frequency power amplifier component,

wherein said third electronic component includes a gain control amplifier circuit which is able to control the amplitude of the transmit signals to be supplied to said high-frequency power amplifier component and supplies the signals with amplitude adjusted in accordance with the level of required output power through control of the gain of said gain control amplifier, depending on the level of required output power, to said high-frequency power amplifier component, when in either of said first operation mode and said second operation mode, and

wherein said third electronic component is configured to supply a signal to indicate which of said first operation mode and said second operation mode to said high-frequency power amplifier component.

9. The radio communication system according to claim 7, wherein said third electronic component includes a storage means for storing table data to determine said control current, depending on the level of required output power, at least in said first operation mode.

10. The radio communication system according to claim 9, further comprising an output power detector circuit which detects the output power of signals output from said high-frequency power amplifier circuit and a power level control circuit which compares a detected power level signal output from the output power detector circuit with a predetermined power level directive signal and generates a control signal to cause said gain control amplifier circuit to change the gain, wherein table data to determine said power level directive signal, depending on the level of required output power, is stored in said storage means.

8. A radio communication system comprising the high-frequency power amplifier component comprising a high-frequency power amplification circuit which comprises power amplifying transistors and is capable of operating in a first operation mode in which said power amplifying transistors amplify and output phase modulated high-frequency signals and in a second operation mode in which said power amplifying transistors amplify and output phase modulated and amplitude modulated high-frequency signals and a bias circuit which applies bias to said power amplifying transistors, said bias causing a changeover between idle currents flowing across said power amplifying transistors in said first operation mode and idle currents flowing across said power amplifying transistors in said second operation mode, wherein said bias circuit is configured to change the idle currents flowing across said power amplifying transistors, depending on the level of power supply voltage and the level of required output power, in said first operation mode, wherein said bias circuit comprises a current-voltage conversion means for converting a supplied control current into a voltage, a current adjusting circuit which adjusts the supplied control current, depending on the level of power supply voltage, by decreasing the current when the power supply voltage level is higher and increasing the current when the power supply voltage level is lower, and a switching means for routing the supplied control current to said current adjusting circuit or said current-voltage conversion means, by bypassing the current adjusting circuit, depending on which operation mode, and wherein the voltage into which the control current has been converted by said current-voltage conversion means is applied to the gate terminal of one of said power amplifying FETs to allow the idle current flow across the power amplifying FET and said switching means is configured to be controlled to route the supplied control current to said current adjusting circuit in the first operation mode, wherein said bias circuit includes a decision means for judging the magnitude of supplied control current and said switching means is configured to make a changeover, according the result of judgment made by said judging means, a second electronic component including a transmission/reception change-over circuit which changes over system operation between transmitting signals and receiving signals, and a third electronic component which modulates transmit signals and inputs modulated transmit signals to said high-frequency power amplifier component,

wherein said third electronic component includes a gain control amplifier circuit which is able to control the amplitude of the transmit signals to be supplied to said high-frequency power amplifier component and supplies the signals with amplitude adjusted in accordance with the level of required output power through control of the gain of said gain control amplifier, depending on the level of required output power, to said high-frequency power amplifier component, when in either of said first operation mode and said second operation mode, and

wherein said third electronic component is configured to supply said control current to said high-frequency power amplifier component.