Patent Publication Number: US-2023133223-A1

Title: Transmission circuit and operation method having output power compensation mechanism

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a transmission circuit and a transmission circuit operation method having output power compensation mechanism. 
     2. Description of Related Art 
     In a communication system, a transmission circuit configured to transmit signals and a receiving circuit configured to receive signals are disposed. The operation of the transmission circuit is to process and convert a digital signal by using a base-band circuit to generate an analog signal such that a frequency up-conversion is performed thereon subsequently to generate a RF signal. The RF signal is then amplified to be delivered by an antenna. 
     However, in the transmission circuit, the power of the amplification circuit that amplifies the RF signal varies due to instant temperature variation. Such a behavior results in either an insufficient power or an excessive power of the transmitted signal. A different receiving result may occur to a remote electronic device that receives such a signal. 
     SUMMARY OF THE INVENTION 
     In consideration of the problem of the prior art, an object of the present invention is to supply a transmission circuit and a transmission circuit operation method having output power compensation mechanism. 
     The present invention discloses a transmission circuit having output power compensation mechanism that includes a base-band and processing circuit, a frequency up-converting circuit, a RF amplification circuit, a temperature monitoring circuit and a calibration circuit. The base-band and processing circuit is configured to receive and process a digital input signal to perform conversion and amplification according to at least one gain parameter to generate an analog output signal. The frequency up-converting circuit is configured to perform frequency up-conversion on the analog output signal to generate a RF signal. The RF amplification circuit is configured to amplify the RF signal to generate an output RF signal to an antenna. The temperature monitoring circuit is configured to monitor and generate an instant temperature value of the RF amplification circuit. The calibration circuit is configured to increase at least a part of the gain parameter when the instant temperature value makes a power of the RF amplification circuit decrease, and decrease at least a part of the gain parameter when the instant temperature value makes the power of the RF amplification circuit increase. 
     The present invention also discloses a transmission circuit operation method having output power compensation mechanism that includes steps outlined below. A digital input signal is received and processed by a base-band and processing circuit to perform conversion and amplification according to at least one gain parameter to generate an analog output signal. Frequency up-conversion is performed on the analog output signal by a frequency up-converting circuit to generate a RF signal. The RF signal is amplified by a RF amplification circuit to generate an output RF signal to an antenna. An instant temperature value of the RF amplification circuit is monitored and generated by a temperature monitoring circuit. At least a part of the gain parameter is increased when the instant temperature value makes a power of the RF amplification circuit decrease, and at least a part of the gain parameter is decreased when the instant temperature value makes the power of the RF amplification circuit increase by a calibration circuit. 
     These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art behind reading the following detailed description of the preferred embodiments that are illustrated in the various figures and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    illustrates a circuit diagram of a transmission circuit having output power compensation mechanism according to an embodiment of the present invention. 
         FIG.  2 A  and  FIG.  2 B  illustrate diagrams of power waveforms of the transmission circuit that performs signal transmission under different usage scenarios according to an embodiment of the present invention. 
         FIG.  3    illustrates a flow chart of a transmission circuit operation method having output power compensation mechanism according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     An aspect of the present invention is to provide a transmission circuit and a transmission circuit operation method having output power compensation mechanism to monitor the temperature of an amplification circuit so as to adjust a gain parameter of a base-band and processing circuit at a front end. The power compensation that compensates the effect of temperature variation on the RF amplification circuit can be accomplished. 
     Reference is now made to  FIG.  1   .  FIG.  1    illustrates a circuit diagram of a transmission circuit  100  having output power compensation mechanism according to an embodiment of the present invention. The transmission circuit  100  includes a base-band and processing circuit  110 , a frequency up-converting circuit  120 , a RF amplification circuit  130 , a temperature monitoring circuit  140  and a calibration circuit  150 . 
     The base-band and processing circuit  110  is configured to receive and process a digital input signal DIS to perform conversion and amplification according to at least one gain parameter to generate an analog output signal AOS. 
     In an embodiment, the base-band and processing circuit  110  includes a base-band signal processing circuit  160  (abbreviated as BBS in  FIG.  1   ), a digital amplitude adjusting circuit  170  (abbreviated as DAA in  FIG.  1   ), a digital-to-analog conversion circuit  180  (abbreviated as DAC in  FIG.  1   ) and an analog amplification circuit  190  (abbreviated as AAC in  FIG.  1   ). 
     The base-band signal processing circuit  160  and the digital amplitude adjusting circuit  170  are a part of a base-band circuit  110 A included in the base-band circuit  110 . The base-band signal processing circuit  160  is configured to perform signal processing on the digital input signal DIS to generate a digital processed signal DPS. The digital amplitude adjusting circuit  170  is configured to amplify the digital processed signal DPS according to a digital gain parameter DAP included in the gain parameter to generate a digital amplified signal DAS. 
     The digital-to-analog conversion circuit  180  and the analog amplification circuit  190  are a part of a processing circuit  110 B included in the base-band circuit  110 . The digital-to-analog conversion circuit  180  is configured to perform digital-to-analog conversion on the digital amplified signal DAS to generate an analog signal AAS. The analog amplification circuit  190  is configured to amplify the analog signal AAS according to an analog gain parameter AAP included in the gain parameter to generate the analog output signal AOS. 
     The frequency up-converting circuit  120  is configured to perform frequency up-conversion on the analog output signal AOS according to a carrier (not illustrated in the figure) to generate a RF signal RFS. 
     The RF amplification circuit  130  is configured to amplify the RF signal RFS to generate an output RF signal ORS to an antenna  195 , so as to be transmitted to a remote electronic apparatus through the antenna  195 . 
     The temperature monitoring circuit  140  is configured to monitor and generate an instant temperature value TV of the RF amplification circuit  130 . In different embodiments, the temperature monitoring circuit  140  can be either disposed outside of and neighboring to the RF amplification circuit  130 , or disposed inside of the RF amplification circuit  130  to perform monitoring. 
     The calibration circuit  150  is configured to increase at least a part of the gain parameter when the instant temperature value TV makes a power of the RF amplification circuit  130  decrease, and is configured to decrease at least a part of the gain parameter when the instant temperature value TV makes the power of the RF amplification circuit  130  increase. 
     In an embodiment, the calibration circuit  150  includes a digital gain compensation circuit  155 A (abbreviated as DGC in  FIG.  1   ) and an analog gain compensation circuit  155 B (abbreviated as AGC in  FIG.  1   ). The digital gain compensation circuit  155 A and the analog gain compensation circuit  155 B are respectively configured to determine the adjusting method according to a relation between the instant temperature value TV and a pre-stored reference temperature value TR. 
     In an embodiment, the calibration circuit  150  is a hardware circuit. The reference temperature value TR is stored in an e-fuse memory or a corresponding driver program (not illustrated in the figure) of such a hardware circuit to be accessed by the calibration circuit  150  to perform determination. In an embodiment, the reference temperature value TR is a pre-selected temperature value. The actual value can be set according to practical requirements, such as but not limited to a temperature value that keep the RF amplification circuit  130  to operate for a time length that is not too long or too short in a room temperature. The present invention is not limited to any fixed value. 
     More specifically, the digital gain compensation circuit  155 A is configured to increase the digital gain parameter DAP when the instant temperature value TV is larger than the reference temperature value TR. In an embodiment, the digital gain compensation circuit  155 A is further configured to retrieve a digital gain compensation table DGT and determine an amount of the digital gain parameter DAP by looking up the digital gain compensation table DGT according to a temperature difference value between the instant temperature value TV and the reference temperature value TR. 
     On the other hand, the analog gain compensation circuit  155 B is configured to decrease the analog gain parameter AAP when the instant temperature value TV is smaller than the reference temperature value TR. In an embodiment, the analog gain compensation circuit  155 B is configured to retrieve an analog gain compensation table AGT and determine an amount of the analog gain parameter AAP by looking up the analog gain compensation table AGT according to the temperature difference value between the instant temperature value TV and the reference temperature value TR. 
     In an embodiment, the digital gain compensation table DGT and the analog gain compensation table AGT are pre-stored in a storage circuit (not illustrated in the figure) further included in the transmission circuit  100 . Further, the digital gain compensation table DGT and the analog gain compensation table AGT can be obtained by using a training process performed on the RF amplification circuit  130  to generate a relation between the temperature and the power. 
     The operation of the transmission circuit  100  under different usage scenarios is described in detail in the following paragraphs. 
     Reference is now made to  FIG.  2 A  and  FIG.  2 B .  FIG.  2 A  and  FIG.  2 B  illustrate diagrams of power waveforms of the transmission circuit  100  that performs signal transmission under different usage scenarios according to an embodiment of the present invention. The X-axis represents time and the Y-axis represents power amount. 
     In  FIG.  2 A  and  FIG.  2 B , time intervals T 1 ˜T 4  are used to illustrate different states of the transmission circuit  100 . In the time intervals T 1  and T 3  labeled as ‘TX’, the transmission circuit  100  performs signal transmission (i.e., receiving the digital input signal DIS and generate the analog output signal AOS). In the time intervals T 2  and T 4 , the transmission circuit  100  stops performing signal transmission. 
     In an embodiment, the transmission circuit  100  can share the antenna  195  with a receiving circuit (not illustrated in the figure) included in a communication that the transmission circuit  100  is located. As a result, in  FIG.  2 A , the power of the receiving circuit is exemplarily illustrated in the time intervals T 2  and T 4  labeled as ‘RX’. However, the present invention is not limited thereto. 
     As illustrated in  FIG.  2 A , in the time interval T 2  of such a usage scenario, the transmission circuit  100  does not operation for a long time until the time interval T 3 . In the time interval T 3 , the transmission circuit  100  performs signal transmission for a longer time. Due to the process from not operating for a long time to keeping operating for a long time, the temperature of the RF amplification circuit  130  keeps raising such that the instant temperature value TV becomes larger than the reference temperature value TR. When the compensation mechanism is absent, the raise of the temperature makes the signal power of the signal outputted by the RF amplification circuit  130  decrease. A steady signal output cannot be obtained such that the power waveform becomes the dotted line section illustrated in  FIG.  2 A . 
     During the long time signal transmission, the raise of the temperature of the RF amplification circuit  130  is not severe. As a result, the calibration circuit  150  can perform minor adjustment on the RF amplification circuit  130  that keeps operating by using the digital gain compensation circuit  155 A. Since the instant temperature value TV is larger than the reference temperature value TR, the digital gain compensation circuit  155 A increases the digital gain parameter DAP. Further, the digital gain compensation circuit  155 A retrieves the digital gain compensation table DGT and determines the amount of the digital gain parameter DAP by looking up the digital gain compensation table DGT according to the temperature difference value between the instant temperature value TV and the reference temperature value TR. 
     As a result, after the operation of the compensation mechanism, a steady signal output can be obtained such that the power waveform becomes the solid line section illustrated in  FIG.  2 A . 
     As illustrated in  FIG.  2 B , in the time interval T 2  of such a usage scenario, the transmission circuit  100  does not operation for a long time until the time interval T 3 . Due to not operating for a long time, the temperature of the RF amplification circuit  130  decreases such that the instant temperature value TV is smaller than the reference temperature value TR. When the compensation mechanism is absent, the decrease of the temperature makes the signal power of the signal outputted by the RF amplification circuit  130  increase. A steady signal output cannot be obtained such that the power waveform becomes the dotted line section illustrated in  FIG.  2 B . 
     Between the state of not operating for a long time and the state of steadily operating, a larger degree of temperature variation occurs to the RF amplification circuit  130 . As a result, the calibration circuit  150  performs a larger degree of adjustment (e.g., an adjusting amount that is 5 times of that of the digital gain compensation circuit  155 A) on the RF amplification circuit  130  that starts to operate and still has a low temperature. Under such a condition, the analog gain compensation circuit  155 B decreases the analog gain parameter AAP since the instant temperature value TV is smaller than the reference temperature value TR. Further, the analog gain compensation circuit  155 B retrieves the analog gain compensation table AGT and determines the amount of the analog gain parameter AAP according to the temperature difference value between the instant temperature value TV and the reference temperature value TR. 
     As a result, after the operation of the compensation mechanism, a steady signal output can be obtained such that the power waveform becomes the solid line section illustrated in  FIG.  2 B . 
     In an embodiment, since the signal transmitted by the RF amplification circuit  130  has a packet length of such as, but not limited to 200 micro seconds and the monitoring of the temperature monitoring circuit  140  performed on the instant temperature value TV only takes a few nano seconds, the monitoring result can be quickly fed back to the calibration circuit  150  to instantly perform adjusting according to the instant temperature variation. 
     It is appreciated that the embodiments described above use the temperature variation caused by the long time or short time operation of the RF amplification circuit  130  as an example. In other embodiments, the calibration circuit  150  can perform power compensation according to the monitoring of the temperature monitoring circuit  140  in response to the temperature variation of the environment that the transmission circuit  100  is located. 
     Further, the embodiment that uses either the digital gain compensation circuit  155 A or the analog gain compensation circuit  155 B to adjust the gain depending on the different temperature conditions is merely an example. In other embodiments, the calibration circuit  150  may selectively use the digital gain compensation circuit  155 A and the analog gain compensation circuit  155 B together to adjust the gain. The present invention is not limited thereto. 
     As a result, the transmission circuit having output power compensation mechanism in the present invention monitors the temperature of an amplification circuit so as to adjust a gain parameter of a base-band and processing circuit at a front end. The power compensation that compensates the effect of temperature variation on the RF amplification circuit can be accomplished. 
     Reference is now made to  FIG.  3   .  FIG.  3    illustrates a flow chart of a transmission circuit operation method  300  having output power compensation mechanism according to an embodiment of the present invention. 
     In addition to the apparatus described above, the present disclosure further provides the transmission circuit operation method  300  having output power compensation mechanism that can be used in such as, but not limited to, the transmission circuit  100  in  FIG.  1   . As illustrated in  FIG.  3   , an embodiment of the transmission circuit operation method  300  includes the following steps. 
     In step S 310 , the digital input signal DIS is received and processed by the base-band and processing circuit  110  to perform conversion and amplification according to at least one gain parameter to generate the analog output signal AOS. 
     In step S 320 , frequency up-conversion is performed on the analog output signal AOS by the frequency up-converting circuit  120  to generate the RF signal RFS. 
     In step S 330 , the RF signal RFS is amplified by the RF amplification circuit  130  to generate the output RF signal ORS to the antenna  195 . 
     In step S 340 , the instant temperature value TV of the RF amplification circuit  130  is monitored and generated by the temperature monitoring circuit  140 . 
     In step S 350 , at least a part of the gain parameter is increased when the instant temperature value TV makes the power of the RF amplification circuit  130  decrease, and at least a part of the gain parameter is decreased when the instant temperature value TV makes the power of the RF amplification circuit  130  increase by the calibration circuit  150 . The gain parameter can be a digital gain parameter DAP corresponding to the amplitude adjusting circuit  170  in the base-band and processing circuit  110 , or an analog gain parameter AAP corresponding to the analog amplification circuit  190  in the base-band and processing circuit  110 . 
     It is appreciated that the embodiments described above are merely an example. In other embodiments, it should be appreciated that many modifications and changes may be made by those of ordinary skill in the art without departing, from the spirit of the disclosure. 
     In summary, the present invention discloses the transmission circuit and the transmission circuit operation method having output power compensation mechanism to monitor the temperature of an amplification circuit so as to adjust a gain parameter of a base-band and processing circuit at a front end. The power compensation that compensates the effect of temperature variation on the RF amplification circuit can be accomplished. 
     The aforementioned descriptions represent merely the preferred embodiments of the present invention, without any intention to limit the scope of the present invention thereto. Various equivalent changes, alterations, or modifications based on the claims of present invention are all consequently viewed as being embraced by the scope of the present invention.