Circuitry for widening the effective range of a transmitter

• US 5,109,538 A
• Filed: 05/02/1990
• Issued: 04/28/1992
• Est. Priority Date: 05/12/1989
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Nokia Mobile Phones UK Limited (Nokia Corporation)
• Inventors: Ikonen, Raimo, Lonka, Pekka, Mikkola, Pekka
• Primary Examiner(s): Kuntz, Curtis
• Application Number:
  US07/519,118
• Time in Patent Office: 727 Days
• Field of Search: 455/115, 455/117, 455/127, 455/128, 455/343, 455/89, 330/129, 330/278, 330/279, 330/284, 330/289, 330/298
• 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 present invention concerns a circuitry for widening the power control range of radio telephone. A radio frequency signal is amplified in a controllable power amplifier (1). According to the invention, after the amplifier a controllable switch (4) is connected, which, while in a first state, does not substantially attenuate the RF power emitted transmitted from the power amplifier (1). The first power control range of the transmitter is thus produced. When the switch (4) is in a second state, it directs part of the RF power transmitted from the power amplifier (1) to a resistive element (R1) and permits part of the RF power to be transmitted to the output (RFout) of the transmitter. A second power control range is produced in this manner.

Claims

1. Circuitry for widening the output power control range of a transmitter of a radio telephone comprising;

a controllable power amplifier for amplifying an output radio frequency power signal derived from the radio telephone, said power amplifier having at least one stage and being operable over a range of output power;

a dissipative element for dissipating power;

controllable switch means connected between the power amplifier and the output of the transmitter of the radio telephone for changing the transmitter output between first and second power control ranges of the transmitter, said switch means including a controllable switch;

said controllable switch being operable in a first state for passing substantially the RF power emitted from the power amplifier to thereby enable formation of the first power control range, said controllable switch being operable in a second state for directing part of the RF power emitted from the power amplifier so as to be consumed in said dissipative element and for allowing part of the power to be transmitted to the output of the transmitter to thereby cause formation of the second power control range, whereby the power control range of the output of the transmitter is widened beyond that of said first power control range by the formation of the second power control range.

2. Circuitry according to claim 1, wherein the switch is a PIN diode switch.

3. Circuitry according to claim 2, wherein the switch comprises two PIN diodes and a quarter-wave transmission line.

4. Circuitry according to claim 1, further comprising means for enabling the state of the switch to be controlled by a logic circuit of the radio telephone.

5. Circuitry according to claim 1 wherein the controllable switch is a PIN diode attenuator of several stages, whereby a number of power control ranges of the transmitter are produced.

6. Circuitry according to claim 1 wherein the transmitter is part of a digital radio telephone.

7. Circuitry according to claim 1, wherein said second power control range includes power levels which are lower in magnitude than power levels within said first power control range.

8. Circuitry according to claim 7, wherein said first and second power control ranges contain some power levels which overlap with each other.

9. Circuitry according to claim 1, wherein said second power control range is said first power control range less said part of the emitted RF power which becomes consumed by said power dissipative element.

10. Circuitry for widening the output power control range of a transmitter of a radio telephone, comprising:

a control loop means including in series connection a controllable gain power amplifier operable on a range of power levels, a power detector and a reference amplifier, said power amplifier emitting RF power derived from a circuit of the transmitter, said reference amplifier controlling the gain of said power amplifier by providing a filtered output thereof which is received by said power amplifier, said reference amplifier receiving a first input signal derived from said power detector and related to the output of said power amplifier, and a second input signal in the form of a control voltage level from logic sections of the radio telephone which indicate a desired output power level, said control loop means tending to be controllable such that voltage levels of the first and second input signals are of equal magnitude; and

controllable switch means connected in series with said control loop means for forming first and second power control ranges, said controllable switch means including a power dissipative element and a switch operable in a first state for passing a major portion of the emitted RF power so as to relate the first power control range to the power range of said power amplifier, said controllable switch being operable in a second state for directing a part of the RF power to become consumed in said power dissipative element and for allowing a remainder of the emitted RF power to pass to an output of the transmitter so as to cause formation of the second power control range, whereby the power control range of the output of the transmitter is widened beyond that of the first power control range by formation of the second power control range.

11. Circuitry according to claim 10, wherein said second power control range includes power levels which are lower in magnitude than at least some of the power levels within said first power control range.

12. Circuitry according to claim 10, wherein said first and second power control ranges contain some power levels which overlap with each other.

13. Circuitry according to claim 10, wherein said second power control range is said first power control range less said part of the emitted RF power which becomes consumed by said power dissipative element.