Transmission power control circuit and transmission device, transmission power control method, program

• US 9,189,005 B2
• Filed: 11/24/2011
• Issued: 11/17/2015
• Est. Priority Date: 11/26/2010
• Status: Expired due to Fees

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Itou, Masatoshi
• Primary Examiner(s): TRINH, TAN H
• Application Number:
  US13/885,880
• Publication Number:
  US 20130237276A1
• Time in Patent Office: 1,454 Days
• Field of Search: 455/522, 455/69, 455/116, 455/115, 455/574, 455/70, 455/127.1, 455/127.2, 323/304, 726/17, 375/345, 375/259, 375/316, 375/297, 375/146, 375/127.3, 330/96
• US Class Current: 1/1
• CPC Class Codes: G05F 3/02 Regulating voltage or current
• CPC Class Codes: H03G 3/3042 in modulators, frequency-changers, transmitters or power amplifiers transmission power control in bidirectional transmission systems H04W52/04
• CPC Class Codes: H04W 52/04 TPC
• CPC Class Codes: H04W 52/52 using AGC [Automatic Gain Control] circuits or amplifiers

Abstract

A transmission power control circuit includes: a frequency conversion unit that converts an input signal to a high frequency signal; a first power control unit that controls power of the input signal before frequency conversion by the frequency conversion unit, in a low frequency band; a second power control unit that controls power of the input signal after frequency conversion by the frequency conversion unit, in a high frequency band; and a controller that controls power using only the first power control unit in a case where a set value of output power is lower than a minimum value of output power at which power control is possible in the second power control unit, the controller controlling the power using the first power control unit and the second power control unit in a case where the set value of the output power is higher than the minimum value of the output power.

Claims

1. A transmission power control circuit comprising:

a frequency conversion unit that converts an input signal to a high frequency signal;

a first power control unit that controls power of the input signal before frequency conversion by the frequency conversion unit, in a low frequency band;

a second power control unit that controls power of the input signal after frequency conversion by the frequency conversion unit, in a high frequency band; and

a controller that controls power using only the first power control unit in a case where a set value of output power is lower than a minimum value of output power at which power control is possible in the second power control unit, the controller controlling the power using the first power control unit and the second power control unit in a case where the set value of the output power is higher than the minimum value of the output power, wherein;

the first power control unit includes a first wave detector, the first wave detector detects part of the input signal, and outputs a first wave detection voltage to the controller,

the second power control unit includes a second wave detector, the second wave detector detects part of the input signal, and outputs a second wave detection voltage to the controller, and

the controller controls power in each of the first power control unit and the second power control unit such that the second wave detection voltage becomes a wave detection voltage target value corresponding to the set value of the output power.

2. The transmission power control circuit according to claim 1, wherein

the minimum value of the output power at which power control is possible in the second power control unit is a minimum value of output power at which power control is possible by the wave detection voltage of the second wave detector of the second power control unit,

the controller controls power in the second power control unit such that output power of the second power control unit is a constant value and controls power in the first power control unit so as to obtain the wave detection voltage target value corresponding to the set value of the output power, in a case where the set value of the output power is lower than the minimum value, and

the controller controls power in the first power control unit so as to obtain the wave detection voltage target value being a fixed value and then controls power in the second power control unit so as to obtain the wave detection voltage target value corresponding to the set value of the output power, in a case where the set value of the output power is higher than the minimum value.

3. The transmission power control circuit according to claim 1, further comprising:

a storage unit that stores a wave detection voltage table including a correspondence table of various set values of output power and target values of wave detection voltages corresponding to the respective set values of the output power,

wherein the controller compares a current set value of output power and a wave detection voltage target value corresponding to the set value of the output power in the wave detection voltage table, upon obtaining wave detection voltages from the wave detectors of each of the first power control unit and the second power control unit,

the controller controls power such that output power of each of the first power control unit and the second power control unit decreases, in a case where a current wave detection voltage is higher than the wave detection voltage target value, and

the controller controls power such that output power of each of the first power control unit and the second power control unit increases, in a case where the current wave detection voltage is lower than the wave detection voltage target value.

4. The transmission power control circuit according to claim 1, wherein

each of the first power control unit and the second power control unit includes an attenuator that attenuates an input signal,

the controller sets a control value of each of the attenuators such that attenuation amount of the attenuator of each of the first power control unit and the second power control unit increases, in a case where a current wave detection voltage is higher than the wave detection voltage target value, and

the controller sets a control value of each of the attenuators such that attenuation amount of the attenuator of each of the first power control unit and the second power control unit decreases, in a case where the current wave detection voltage is lower than the wave detection voltage target value.

5. The transmission power control circuit according to claim 4, comprising:

a storage unit that stores fixed gain set value for setting a transmission gain in the second power control unit to a constant value,

the controller setting the attenuator of the second power control unit to a control value based on the fixed gain set value, in a case where the set value of the output power is lower than the minimum value.

6. A transmission device for radio communication, comprising:

the transmission power control circuit according to claim 1,

wherein the transmission device controls power by the transmission power control circuit such that power of an output signal becomes constant, and outputs the output signal.

7. A transmission power control method comprising:

performing first power control of an input signal in a low frequency band;

converting the input signal after the power control to a high frequency signal;

performing second power control of the input signal after the frequency conversion in a high frequency band; and

performing power control using only the first power control in a case where a set value of out is lower than a minimum value of output power at which power control is possible in the second power control, and performing power control using the first power control and the second power control in a case where the set value of the output power is higher than the minimum value of the output power, wherein;

the first power control detects part of an input signal, and outputs a first wave detection voltage,

the second power control detects part of an input signal, and outputs a second wave detection voltage, and

power control is performed in each of the first power control and the second power control such that the second wave detection voltage becomes a wave detection voltage target value corresponding to the set value of the output power.