Radio transceiver including transmitter power control circuit

• US 5,832,374 A
• Filed: 11/01/1996
• Issued: 11/03/1998
• Est. Priority Date: 11/19/1993
• Status: Expired due to Term

• Current Assignee: ST-Ericcson SA (Telefonaktiebolaget LM Ericsson)
• Original Assignee: US Philips Corporation (Koninklijke Philips N.V.)
• Inventors: Marshall, Christopher, Birth, Winfrid, Saur, Erich
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): BANKS HAROLD, MARSHA DENISE
• Application Number:
  US08/742,330
• Time in Patent Office: 732 Days
• Field of Search: 455/89, 455/115, 455/126, 455/127, 455/575, 330/129, 330/279
• US Class Current: 455/127.2
• CPC Class Codes: H03G 3/3042 in modulators, frequency-changers, transmitters or power amplifiers transmission power control in bidirectional transmission systems H04W52/04

Abstract

The invention relates to a radio transceiver having a high-frequency output stage and a control circuit for controlling the transmitter power, in which the control circuit is supplied with an actual voltage in the form of a signal derived from the transmit signal. Especially in handheld radios the environment of the antenna is affected by the position of the unit, so that antenna mismatches constantly occur. This can disturb the proper operation of state-of-the-art power control circuits. To avoid such interference, the invention proposed to supply as an actual value to the control circuit a signal which is tapped prior to the signal being supplied to the high-frequency power amplifier output stage.

Claims

1. A radio transceiver, comprising:

a gain controlled high-frequency driver amplifier stage having a signal output and having a control input for controlling the gain of the driver amplifier stage;

a high-frequency power amplifier output stage having substantially constant gain, an input coupled to the signal output of the driver amplifier stage, and an output coupled to an antenna by coupling means which does not include any means for extracting, for the purpose of feedback control, a portion of power flowing in the coupling means;

a high-frequency rectifier stage connected to the signal output of the driver amplifier stage for producing a control signal representing the amplitude of an HF signal outputted by the driver amplifier stage;

a reference voltage source for producing a reference voltage representing a desired output power of the output stage; and

a differential control amplifier stage responsive to the control signal produced by the rectifier stage and the reference voltage produced by the reference voltage source for producing a difference control voltage, the difference control voltage being supplied to the control input of the driver amplifier stage;

wherein a constant relationship is maintained between at least one characteristic of the rectifier stage and one characteristic of the output stage;

whereby the gain of the driver amplifier stage is controlled by the difference control voltage, thereby controlling the output power of the output stage.

2. The radio transceiver as claimed in claim 1, characterized in that the radio transceiver is a mobile radio transceiver for time division multiple access (TDMA) operation.

3. The radio transceiver as claimed in claim 1, wherein the characteristic is the gain of the respective output stage and the rectifier stage.

4. A radio transceiver, comprising:

a gain controlled high-frequency driver amplifier stage having a signal output and having a control input for controlling the gain of the driver amplifier stage;

a high-frequency power amplifier output stage having substantially constant gain, an input coupled to the signal output of the driver amplifier stage, and an output coupled to an antenna by coupling means which does not include any means for extracting, for the purpose of feedback control, a portion of power flowing in the coupling means;

a high-frequency rectifier stage connected to the signal output of the driver amplifier stage for producing a control signal representing the amplitude of an HF signal outputted by the driver amplifier stage;

a reference voltage source for producing a reference voltage representing a desired output power of the output stage;

a differential control amplifier stage responsive to the control signal produced by the rectifier stage and the reference voltage produced by the reference voltage source for producing a difference control voltage, the difference control voltage being supplied to the control input of the driver amplifier stage;

wherein at least the output stage and the rectifier stage are implemented in a single integrated circuit.

5. A radio transceiver, comprising:

a gain controlled high-frequency driver amplifier stage having a signal output and having a control input for controlling the gain of the driver amplifier stage;

a high-frequency power amplifier output stage having substantially constant gain, an input coupled to the signal output of the driver amplifier stage, and an output coupled to an antenna by coupling means which does not include any means for extracting, for the purpose of feedback control, a portion of power flowing in the coupling means;

a high-frequency rectifier stage connected to the signal output of the driver amplifier stage for producing a control signal representing the amplitude of an HF signal outputted by the driver amplifier stage;

a reference voltage source for producing a reference voltage representing a desired output power of the output stage; and

a differential control amplifier stage responsive to the control signal produced by the rectifier stage and the reference voltage produced by the reference voltage source for producing a difference control voltage, the difference control voltage being supplied to the control input of the driver amplifier stage;

wherein the gain of the rectifier stage remains closely matched to the gain of the output stage;

whereby the gain of the driver amplifier stage is controlled by the difference control voltage, thereby controlling the output power of the output stage.