JP2008131113A - Multiplexed power supply circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the power efficiency of a power supply circuit used in a radio transmission apparatus, including a base station of a cellular telephone. <P>SOLUTION: A plurality of power supply circuits having different characteristics are provided in the radio transmission apparatus and the optimum power supply circuit is operated under each radio output condition, thereby enabling a power supply circuit to always operate with high power efficiency. As the result, the total power efficiency in the radio transmission apparatus can be improved. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a multiplexed power supply circuit in a radio transmission apparatus such as a mobile phone base station.

  In recent mobile phone base stations, attention has been paid to the efficiency of radio output power versus power consumption of radio transmitters, and semiconductor components and control circuit systems used in radio transmitter circuits have been developed to improve the efficiency. . On the other hand, the power efficiency of the power supply circuit used in the wireless transmission unit cannot be ignored.

  An example of a system diagram of a conventional wireless transmission device is shown in FIG. The wireless transmission device includes a transmission control unit 1, a wireless transmission unit 2, and a power supply circuit 3. A wireless transmission circuit 2A is provided in the wireless transmission unit 2, and an amplifier 5 is further provided in the wireless transmission circuit 2A. . The transmission control unit 1 performs data conversion or the like on the transmission data input signal input from the outside, and the wireless transmission unit 2 modulates and amplifies the data in response to the output result from the transmission control unit 1. The external power input is converted into a power supply voltage to be used in each circuit inside the wireless transmission device by the power supply circuit 3 and used.

  The relationship between the power load ratio in the power supply circuit 3 (the ratio of the output power in actual use to the maximum output power that can be output without impairing the performance of the power supply circuit) and the power efficiency is constant and high efficiency as shown in FIG. Although most ideal, a normal power supply circuit has a characteristic that its power efficiency changes as the power supply load factor changes as shown in FIG. For example, in the case of the power supply circuit A in FIG. 9, the power efficiency becomes maximum at a high load, but the efficiency deteriorates at a low load. In the case of the power supply circuit C in FIG. 9, the power efficiency is maximized at low loads, but the characteristics are different for each power supply circuit, such as degradation in efficiency at high loads. Is difficult to achieve technically. On the other hand, in a wireless transmission device, the wireless output power is not always constant, and often varies depending on wireless output conditions such as frequency carrier and speech channel increase / decrease.

  As an example, FIG. 10 shows an operation example of a conventional method in consideration of the wireless output condition with respect to the characteristics of the power supply circuit C in FIG. When the wireless output condition of the wireless transmission device is, for example, wireless output condition 2 in FIG. 10, the power supply circuit operates at a portion where the power efficiency of the power supply circuit is the highest, so that power loss in the power supply circuit C (in FIG. 10) Loss b) can be kept small. However, when the wireless transmission device operates under the wireless output condition 1 and the wireless output condition 3 in FIG. 10, the power loss of the power supply circuit C (loss a in FIG. And loss c) becomes large.

  The present invention has been made in order to solve the above-described problems, and by preparing a plurality of power supply circuits in a wireless transmission device and operating an optimum multiplexed power supply circuit for each wireless output condition, the present invention is always highly efficient. An object of the present invention is to provide a multiplexed power supply circuit that achieves high power efficiency, and as a result, to improve the overall power efficiency of a wireless transmission device.

  In order to solve the above-described problems, the present invention is used in a wireless transmission device in a wireless transmission unit that modulates and amplifies data, a plurality of power supply circuits that have different optimum power efficiencies depending on output power, and the wireless transmission unit One or a plurality of power supply circuits based on a determination result of the wireless transmission output determination unit, and a wireless output determination unit that determines the power required for the wireless transmission output to be performed based on at least a transmission control signal and transmission output data A power source selection unit that selects and outputs the selected data to the wireless transmission unit.

  According to the present invention, it is possible to improve the power efficiency in the power supply circuit by reducing the power loss in the power supply circuit in the wireless output device.

(Embodiment 1)
FIG. 1 shows an example of a system diagram of the wireless transmission device in this embodiment. The wireless transmission device in the present embodiment includes a transmission control unit 1, a wireless transmission unit 2, a power supply circuit 3A, and a power supply circuit 3B. The transmission control unit 1 includes a wireless output determination unit 4 and a power source selection unit 6 therein. The wireless transmission unit 2 includes a wireless transmission circuit 2A therein, and the wireless transmission circuit 2A includes an amplifier 5 therein. The wireless output determination unit 4 and the power supply selection unit 6 can be provided outside the transmission control unit 1.

  The conventional wireless transmission device (FIG. 7) has a single power supply circuit, whereas the wireless transmission device of this embodiment is characterized in that a plurality of power supply circuits are provided. In this embodiment, two power supply circuits are used, but the numerical values are not limited.

  FIG. 2 shows an example of power supply circuit characteristics of each power supply circuit in this embodiment. The power supply circuit 3A has the maximum power efficiency when the power supply output power is low (a [w] in FIG. 2), and the power supply circuit 3B has power when the power supply output power is high (b [w] in FIG. 2). It shall have the characteristic that efficiency is maximized.

  Based on the characteristics of the power supply circuit 3A and the power supply circuit 3B in FIG. 2, the operation of the present embodiment will be described with reference to the system diagram of FIG. 1 and FIGS.

  The transmission control unit 1 performs data conversion on the transmission output data input signal input from the outside, and the wireless transmission unit 2 modulates and amplifies data in response to the output result from the transmission control unit 1. The wireless output determination unit 4 performs power calculation from information on the transmission control signal and the transmission output data input signal input to the transmission control unit 1 and determines the power required for the wireless transmission output. In the determination at this time, by using the result (transmission output detection input in FIG. 1) of detecting the wireless transmission output state obtained from the wireless transmission unit 2 that is currently output, the wireless output determination unit 4 can also perform finer control. In response to the determination result of the wireless output determination unit 4, the power supply selection unit 6 performs on / off control (selection) of the power supply circuit 3A and the power supply circuit 3B.

  For example, when the wireless output determination unit 4 determines that the wireless output condition 1 (the power supply output power is near a [w]) in FIG. 4 at time T1 in FIG. 3, the determination result is received. The power supply selection unit 6 controls the power supply circuit 3A to be on and the power supply circuit 3B to be off. As a result, only the most efficient power supply circuit 3A operates at the power supply output power a [w], so that the power efficiency is improved as compared with the conventional method.

  When the wireless output determination unit 4 determines that the wireless output condition 2 (power supply output power is near b [w]) in FIG. 4 at time T2 in FIG. The selection unit 6 controls the power supply circuit 3A to be turned off and the power supply circuit 3B to be turned on. Thereby, only the most efficient power supply circuit 3B operates with the power supply output power b [w].

  When the wireless output determination unit 4 determines that the wireless output condition 3 (power supply output power is near c [w]) in FIG. 4 at time T3 in FIG. The selector 6 controls both the power supply circuit 3A and the power supply circuit 3B to the on state. Here, when the power output power c [w] is c = a + b, both the power supply circuit 3A and the power supply circuit 3B operate at the maximum efficiency, so that the power efficiency is improved as compared with the conventional method.

  The power of the power supply circuit 3A and the power supply circuit 3B is synthesized using a low-loss Schottky barrier diode or the like, but power supply to the wireless transmission unit 2 is not interrupted during operation of the wireless transmission device. When switching from the power supply circuit 3A to the power supply circuit 3B, the power supply overlap time is provided at the control timing of on and off, and the power supply from the power supply circuit is stabilized.

  As described above, by arranging a plurality of power supply circuits and performing operation control and synthesis of the power supply circuits, the power efficiency of the power supply circuit can always be brought close to high efficiency and constant as shown in FIG. .

  According to the present embodiment, even when wireless output conditions vary, it is possible to achieve high efficiency by deploying a plurality of power supply circuits having different characteristics and optimizing the combination with the wireless output conditions. Is possible.

(Embodiment 2)
In this embodiment, the wireless transmission device includes a plurality of power supply circuits and a plurality of wireless transmission circuits, and combines a power supply circuit optimized according to wireless output conditions and the wireless transmission circuit. By further multiplexing the system from the power supply circuit to the wireless transmission circuit in this way, further increase in efficiency is realized. Moreover, it can be applied to a Doherty amplifier that has been registered for radio characteristics having a large peak factor (ratio of peak power to average power), such as third-generation mobile phones. In the present embodiment, a case where a Doherty amplifier is installed as an amplifier in a wireless transmission unit in a wireless transmission device provided with a plurality of power supply circuits and a plurality of wireless transmission circuits will be described as an example. The Doherty amplifier has an amplifier (carrier amplifier) that always performs signal amplification operation and an amplifier (peak amplifier) called a peak amplifier or auxiliary amplifier that operates only at the time of high power output, and receives the input signal as a carrier amplifier. And the output from the carrier amplifier and the peak amplifier are combined and output from the carrier amplifier and the peak amplifier.

  FIG. 5 shows an example of a system diagram of the wireless transmission device when the system from the power supply circuit to the wireless transmission circuit is multiplexed. The wireless transmission device in the present embodiment includes a transmission control unit 1, a wireless transmission unit 2, a power supply circuit 3C, and a power supply circuit 3D. The transmission control unit 1 includes a wireless output determination unit 4 and a power source selection unit 6 therein. The wireless transmission unit 2 includes a wireless transmission circuit 2B therein, and the wireless transmission circuit 2B includes a carrier amplifier 5A therein. The wireless transmission unit 2 includes a wireless transmission circuit 2C inside, and the wireless transmission circuit 2C further includes a peak amplifier 5B. As in the first embodiment, the wireless output determination unit 4 and the power supply selection unit 6 can be arranged outside the transmission control unit 1.

  By combining the power supply circuit 3C and the wireless transmission circuit 2B of FIG. 5 (hereinafter referred to as “carrier amplifier system”) and combining the power supply circuit 3D and the wireless transmission circuit 2C (hereinafter referred to as “peak amplifier system”), The system up to the wireless transmission circuit is multiplexed. Further, the power supply circuit 3C has a characteristic that realizes optimum power efficiency with the wireless output average power as shown in FIG. 6A, and the power supply circuit 3D has power obtained by subtracting the average power from the peak power as shown in FIG. 6B. Therefore, the characteristic is to operate with optimum power efficiency.

  The operation of this embodiment will be described with reference to the system diagram of FIG. 5 and FIG.

  The wireless output determination unit 4 performs power calculation from information on the transmission control signal and the transmission output data input signal input to the transmission control unit 1, and determines the power necessary for the wireless transmission output. In response to the determination result of the wireless output determination unit 4, the power supply selection unit 6 performs on / off control of the power supply circuit 3C or the power supply circuit 3D. As shown in FIG. 6C, when the wireless output determination unit 4 determines that the power required for the wireless transmission output is within the average power, the power supply selection unit 6 turns on the power supply circuit 3C and turns on the power supply circuit 3D. By controlling it to be off, only the carrier amplifier system is operated. When the wireless output determination unit 4 determines that the power exceeding the average power is required, the power supply selection unit 6 controls both the power supply circuits 3C and 3D to on. As a result, the power supply output power of the carrier amplifier system operates the peak amplifier system in parallel while maintaining the power state where the maximum efficiency is maintained. Thus, desired transmission output power can be realized with high efficiency. Other operations are the same as those in the first embodiment.

3 is a system diagram of a wireless transmission device in Embodiment 1. FIG. FIG. 3 is a diagram illustrating power supply characteristics used in the first embodiment. 6 is a diagram for explaining an operation related to switching control in Embodiment 1. FIG. 6 is a diagram for explaining an operation in the first embodiment. FIG. FIG. 6 is a system diagram of a wireless transmission device in a second embodiment. FIG. 10 is a diagram for explaining the operation in the second embodiment (Doherty amplifier). It is a systematic diagram of the conventional wireless transmitter. It is a figure which shows the power supply characteristic of an ideal power supply circuit. It is a figure which shows the power supply characteristic of the power supply circuit of a prior art. It is a figure explaining operation | movement of a prior art.

Explanation of symbols

    DESCRIPTION OF SYMBOLS 1 Transmission control part, 2 Wireless transmission part, 2A Wireless transmission circuit, 2B Wireless transmission circuit (carrier amplifier system) in Embodiment 2 2C Wireless transmission circuit (peak amplifier system) in Embodiment 2 3 Power supply circuit, 3A Power circuit in the first embodiment, 3B Power circuit in the first embodiment, 3C Power circuit in the second embodiment (carrier amplifier system), 3D Power circuit in the second embodiment (peak amplifier system), 4 Wireless output determination unit 5, amplifier, 5A carrier amplifier, 5B peak amplifier, 6 power supply selection unit.

Claims (1)

A wireless transmitter for modulating and amplifying data;
A plurality of power supply circuits whose optimum power efficiency differs depending on the output power;
A wireless output determination unit that determines power required for wireless transmission output used in the wireless transmission unit based on at least a transmission control signal and transmission output data;
A wireless transmission device comprising: a power supply selection unit that selects one or a plurality of the power supply circuits based on a determination result of the wireless transmission output determination unit and causes the wireless transmission unit to output the selected one.

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