High-frequency power amplification electronic part and wireless communication system

Abstract

A high-frequency power amplification electronic part is disclosed which comprises a power amplifier circuit and a bias control circuit, the power amplifier circuit having a plurality of amplifier stages for amplifying an input high-frequency signal, the bias control circuit acting to bias the power amplifier circuit. The power amplifier circuit controls output power in accordance with input power that is varied while a gain of the power amplifier circuit is being fixed by either a bias current or a bias voltage supplied from the bias control circuit. The bias control circuit supplies at least two diode characteristic elements with a predetermined current each in order to generate at least two voltages demonstrating different temperature characteristics, the bias control circuit further using the generated voltages as a basis for generating either a plurality of bias currents or a plurality of bias voltages having a desired temperature-dependent rate of change each, the generated bias currents or bias voltages being fed to each of the plural amplifier stages constituting the power amplifier circuit.

What is claimed is:  
     
         1 . A high-frequency power amplification electronic part comprising a power amplifier circuit and a bias control circuit, said power amplifier circuit having a plurality of amplifier stages for amplifying an input high-frequency signal, said bias control circuit acting to bias said power amplifier circuit, 
 wherein said power amplifier circuit controls output power in accordance with input power that is varied while a gain of said power amplifier circuit is being fixed by either a bias current or a bias voltage supplied from said bias control circuit, and    wherein said bias control circuit supplies at least two diode characteristic elements with a predetermined current each in order to generate at least two voltages demonstrating different temperature characteristics, said bias control circuit further using the generated voltages as a basis for generating either a plurality of bias currents or a plurality of bias voltages having a desired temperature-dependent rate of change each, the generated bias currents or bias voltages being fed to each of said plural amplifier stages constituting said power amplifier circuit.    
     
     
         2 . A high-frequency power amplification electronic part according to  claim 1 , wherein said bias control circuit generates said plural bias currents or said plural bias voltages having a different current value or a different voltage value each at a specific temperature on the basis of a reference voltage or a reference current.  
     
     
         3 . A high-frequency power amplification electronic part according to  claim 1  or  2 , wherein said at least two diode characteristic elements are formed so as to have the same size and the same characteristics each and are arranged to generate two voltages each manifesting a different temperature characteristic depending on a magnitude of the supplied current.  
     
     
         4 . A high-frequency power amplification electronic part according to  claim 1  or  2 , wherein said at least two diode characteristic elements are formed so as to have the same size and the same characteristics each and to constitute a first group of n parallelly connected elements and a second group of m parallelly connected elements, n being a positive integer, m being a positive integer different from n, said diode characteristic elements further generating two voltages each manifesting a different temperature characteristic when the current of the same magnitude is supplied to said first group and said second group.  
     
     
         5 . A high-frequency power amplification electronic part according to any one of claims  1  through  4 , wherein the current supplied to said diode characteristic elements is generated by a current mirror circuit inputting an externally supplied reference current.  
     
     
         6 . A high-frequency power amplification electronic part according to any one of claims  3  through  5 , wherein said bias control circuit comprises: 
 an error amplifier circuit for amplifying a potential difference between the two voltages generated by said diode characteristic elements;  
 a first amplifier circuit for converting an output voltage of said error amplifier circuit into a current;  
 a first transistor group comprised of a plurality of transistors connected to either an output transistor of said first amplifier circuit or a transistor receiving an output of said first amplifier circuit for current mirroring purposes;  
 a second amplifier circuit for inputting a reference voltage so as to convert the voltage into a current; and  
 a second transistor group comprised of a plurality of transistors connected to either an output transistor of said second amplifier circuit or a transistor receiving an output of said second amplifier circuit for current mirroring purposes,  
 wherein either said bias currents obtained by subtracting from the currents of the transistors constituting said first transistor group the currents of the corresponding transistors constituting said second transistor group, or said bias voltages acquired through conversion from the currents thus obtained, are supplied to said power amplifier circuit.  
 
     
     
         7 . A high-frequency power amplification electronic part according to  claim 5 , wherein said bias control circuit comprises: 
 an error amplifier circuit for amplifying a potential difference between the two voltages generated by said diode characteristic elements;    a first amplifier circuit for converting an output voltage of said error amplifier circuit into a current;    a first transistor group comprised of a plurality of transistors connected to either an output transistor of said first amplifier circuit or a transistor receiving an output of said first amplifier circuit for current mirroring purposes; and    a second transistor group comprised of a plurality of transistors connected for current mirroring purposes to a transistor supplied with a mirrored current from said current mirror circuit,    wherein either said bias currents obtained by subtracting from the currents of the transistors constituting said first transistor group the currents of the corresponding transistors constituting said second transistor group, or said bias voltages acquired through conversion from the currents thus obtained, are supplied to said power amplifier circuit.    
     
     
         8 . A high-frequency power amplification electronic part according to  claim 6 , further comprising: 
 first switching means interposed between the output transistor of said first amplifier circuit or the transistor receiving the output of said first amplifier circuit on the one hand, and each of the transistors constituting said first transistor group on the other hand, said first switching means enabling or disabling the input either to said output transistor of said first amplifier circuit or to said transistor receiving the output of said first amplifier circuit; and    second switching means interposed between the output transistor of said second amplifier circuit or the transistor receiving the output of said second amplifier circuit on the one hand, and each of the transistors constituting said second transistor group on the other hand, said second switching means enabling or disabling the input either to said output transistor of said second amplifier circuit or to said transistor receiving the output of said second amplifier circuit.    
     
     
         9 . A high-frequency power amplification electronic part according to  claim 7 , further comprising: 
 first switching means interposed between the output transistor of said first amplifier circuit or the transistor receiving the output of said first amplifier circuit on the one hand, and each of the transistors constituting said first transistor group on the other hand, said first switching means enabling or disabling the input either to said output transistor of said first amplifier circuit or to said transistor receiving the output of said first amplifier circuit; and    second switching means interposed between the transistor supplied with said mirrored current from said current mirror circuit on the one hand, and each of the transistors constituting said second transistor group and connected for current mirroring purposes to said transistor supplied with said mirrored current from said current mirror circuit on the other hand, said second switching means enabling or disabling the voltage of said transistor supplied with said mirrored current from said current mirror circuit.    
     
     
         10 . A high-frequency power amplification electronic part according to any one of claims  6  through  9 , wherein a buffer circuit is provided upstream of said error amplifier circuit, said buffer circuit converting in impedance the two voltages generated by said diode characteristic elements and inputting the converted voltages to said error amplifier circuit.  
     
     
         11 . A high-frequency power amplification electronic part according to any one of claims  1  through  10 , further comprising: 
 a first high-frequency power amplifier circuit for amplifying an outgoing signal on a first frequency band and outputting the amplified signal; and  
 a second high-frequency power amplifier circuit for amplifying an outgoing signal on a second frequency band and outputting the amplified signal,  
 wherein said bias control circuit generates either the bias currents or the bias voltages for said first high-frequency power amplifier circuit as well as for said second high-frequency power amplifier circuit.  
 
     
     
         12 . A wireless communication system comprising: 
 a high-frequency power amplification electronic part according to any one of claims  1  through  11 ;    a second electronic part which has a variable gain amplifier circuit for amplifying an outgoing signal and which inputs the signal modulated by said variable gain amplifier circuit to said high-frequency power amplification electronic part; and    third electronic part including: 
 level detecting means for detecting an output level of the outgoing signal output by said high-frequency power amplification electronic part; and  
 a control circuit which, based on a detection signal coming from said level detecting means and a signal designating the output level, generates an output control signal for controlling the gain of said variable gain amplifier circuit, said control circuit further supplying the generated output control signal to said second electronic part.  
   
     
     
         13 . A wireless communication system according to  claim 12 , wherein said third electronic part supplies said bias control circuit with said reference voltage or said reference current for use by said bias control circuit, as well as with a signal for specifying activation of either said first high-frequency power amplifier circuit or said second high-frequency power amplifier circuit selectively.