Power supply unit, semiconductor device, and wireless communication device

Abstract

The present invention realizes stabler output voltage variable control in a power supply unit. A power supply unit capable of changing dynamic output voltage has: a first regulator for dropping down voltage by a switching method and outputting the resultant voltage to a first node; and a second regulator for dropping down the input voltage by a voltage drop and outputting the resultant voltage to the first node. In the case where a target voltage instructed by first information is larger than a predetermined threshold voltage, the power supply unit controls so that the voltage of the first node becomes the target voltage and stops supply of voltage from the second regulator. In the case where the target voltage is smaller than the predetermined threshold voltage, the power supply unit controls the second regulator so that the voltage of the first node becomes the target voltage and stops output of voltage from the first regulator.

1 - 12 . (canceled) 
     
     
         13 . A transmitter configured to supply power to a receiver by radio, the transmitter comprising:
 a matching circuit configured to match impedances of the transmitter and the receiver;   a driving circuit configured to drive the matching circuit;   a power generator circuit configured to supply an internal power to the driving circuit, the power generator circuit comprising
 a first regulator configured to generate a first voltage; and 
 a second regulator configured to generate a second voltage higher than the first voltage; and 
   a communication circuit configured to output information data for controlling the receiver and driving control data for controlling the power generator circuit,   wherein the power generator circuit is configured to output the first voltage or the second voltage to the driving circuit according to the driving control data.   
     
     
         14 . The transmitter according to  claim 13 ,
 wherein the driving circuit is configured to output a communication signal to the matching circuit according to the information data and the first voltage, and is configured to output a supply power signal to the matching circuit according to the second voltage, and   wherein the matching circuit is configured to transmit the communication signal and the supply power signal to the receiver.   
     
     
         15 . The transmitter according to  claim 14 ,
 wherein the driving circuit amplifies the communication signal according to the first voltage, and amplifies the supply power signal according to the second voltage.   
     
     
         16 . The transmitter according to  claim 15 ,
 wherein the power generator outputs the first voltage to the driving circuit when the transmitter transmits the communication signal to the receiver, and   wherein the power generator outputs the second voltage to the driving circuit when the transmitter transmits the supply power signal to the receiver.   
     
     
         17 . The transmitter according to  claim 16 ,
 wherein the first regulator comprises a series regulator, and   wherein the second regulator comprises a switching regulator.   
     
     
         18 . The transmitter according to  claim 13 ,
 wherein the driving control data includes a destination value indicating a voltage of the internal power,   wherein the power generator circuit has a threshold voltage for controlling the first and second regulator,   wherein the power generator circuit outputs the first voltage to the driving circuit when the destination value is lower than the threshold voltage, and   wherein the power generator circuit outputs the second voltage to the driving circuit when the destination value is higher than the threshold voltage.   
     
     
         19 . The transmitter according to  claim 18 ,
 wherein the communication circuit s configured to receive a supply power control data from the receiver, the supply power control data indicating a state of power of the receiver, and   wherein the destination value is determined based on the supply power control data.   
     
     
         20 . The transmitter according to  claim 16 ,
 wherein the power generator alternates between outputting the communication signal and outputting the power supply signal.   
     
     
         21 . The transmitter according to  claim 20 ,
 wherein a time between stopping of the outputting of the power supply signal and starting of the outputting of the communication signal is less than a time between stopping of the outputting of the communication signal and starting of the outputting of the power supply signal.   
     
     
         22 . The transmitter according to  claim 18 , further comprising a backflow prevention circuit coupled to an output of the first regulator. 
     
     
         17 . The transmitter according to  claim 17 ,
 wherein the power generator outputs the communication signal using the series regulator but not the switching regulator such that the communication signal contains no switching noise caused by the switching regulator.   
     
     
         24 . The transmitter according to  claim 14 ,
 wherein the driving circuit and the matching circuit are configured to output the first and second voltages to the receiver via electromagnetic induction.   
     
     
         25 . The transmitter according to  claim 24 ,
 wherein the driving circuit and the matching circuit are configured to output the first and second voltages to the receiver via Near Field Communication (NFC).