Voltage to current converter

Abstract

The voltage to current converter according to the present embodiments includes a charge transfer device, a smoother and a current generator. The charge transfer device accumulates charge corresponding to an input voltage, and transfers the accumulated charge. The smoother accumulates the transferred charge to smooth an output voltage. The current generator generates a current corresponding to the input voltage by use of a current corresponding to the charge accumulated in the smoother.

1 . A voltage to current converter comprising:
 a charge transfer device that accumulates charge corresponding to an input voltage and transfers the accumulated charge;   a smoother that accumulates the transferred charge and smooths an output voltage; and   a current generator that generates a current corresponding to the input voltage by use of a current corresponding to the charge accumulated in the smoother;   wherein the charge transfer devise comprises:
 a first switch and a second switch that are connected in series between an input terminal of the input voltage and an input node of the current generator; and 
 a first capacitor, at least one end of which is connected between the first switch and the second switch, that accumulates or discharges charge corresponding to the input voltage; 
 a third switch that switches whether or not charge corresponding to a first reference voltage based on temperature characteristics of the current generator is accumulated in the first capacitor; and 
 a fourth switch that switches whether or not charge corresponding to a second reference voltage based on the temperature characteristics of the current generator is accumulated in the first capacitor 
   wherein the current generator comprises:
 a second capacitor that accumulates or discharges charge corresponding to a current caused by discharge of the first capacitor; and 
 a current mirror circuit that comprises a first current path passing a first current corresponding to the accumulated charge in the second capacitor and a second current path passing a second current in proportion to the first current. 
   
     
     
         2 . The voltage to current converter according to  claim 1 , wherein
 the first switch is connected between the input terminal of the input voltage and the one end of the first capacitor,   the second switch is connected between the other end of the first capacitor and the input node of the current generator,   the third switch is connected between an input terminal of the first reference voltage and the one end of the first capacitor, and   the fourth switch is connected between the other end of the first capacitor and an input terminal of the second reference voltage.   
     
     
         3 . The voltage to current converter according to  claim 1 , wherein
 the first switch is connected between the input terminal of the input voltage and the one end of the first capacitor,   the second switch is connected between the one end of the first capacitor and the input node of the current generator,   the third switch is connected between an input terminal of the first reference voltage and the other end of the first capacitor, and   the fourth switch is connected between the other end of the first capacitor and an input terminal of the second reference voltage.   
     
     
         4 . The voltage to current converter according to  claim 2 , wherein
 the first switch and the fourth switch are synchronized and turned on or off,   the second switch and the third switch are synchronized and turned on or off,   the second switch and the third switch are turned on during a period in which the first switch and the fourth switch are off, and   the second switch and the third switch are turned off during a period in which the first switch and the fourth switch are on.   
     
     
         5 . The voltage to current converter according to  claim 1 , wherein
 the charge transfer device comprises:   a third switch that switches whether or not charge corresponding to a first reference voltage based on temperature characteristics of the current generator is accumulated in the first capacitor; and   a fifth switch that switches whether or not charge corresponding to the input voltage is accumulated in the first capacitor.   
     
     
         6 . The voltage to current converter according to  claim 5 , wherein
 the first switch is connected between the input terminal of the input voltage and the one end of the first capacitor,   the second switch is connected between the other end of the first capacitor and the input node of the current generator,   the third switch is connected between an input terminal of the first reference voltage and the one end of the first capacitor, and   the fifth switch is connected between the other end of the first capacitor and the input terminal of the input voltage.   
     
     
         7 . The voltage to current converter according to  claim 5 , wherein
 the first switch is connected between the input terminal of the input voltage and the one end of the first capacitor,   the second switch is connected between the one end of the first capacitor and the input node of the current generator,   the third switch is connected between an input terminal of the first reference voltage and the other end of the first capacitor, and   the fifth switch is connected between the input terminal of the input voltage and the other end of the first capacitor.   
     
     
         8 . The voltage to current converter according to  claim 4 , wherein
 the first switch and the second switch are synchronized and turned on or off,   the third switch and the fifth switch are synchronized and turned on or off,   the third switch and the fifth switch are turned on during a period in which the first switch and the second switch are off, and   the third switch and the fifth switch are turned off during a period in which the first switch and the second switch are on.   
     
     
         9 . The voltage to current converter according to  claim 5 , wherein
 the first switch and the third switch are synchronized and turned on or off,   the second switch and the fifth switch are synchronized and turned on or off,   the second switch and the fifth switch are turned on during a period in which the first switch and the third switch are off, and   the second switch and the fifth switch are turned off during a period in which the first switch and the third switch are on.   
     
     
         10 . The voltage to current converter according to  claim 1 , wherein
 the first switch is connected between the input terminal of the input voltage and the one end of the first capacitor,   the second switch is connected between the one end of the first capacitor and the input node of the current generator, and   the charge transfer device comprises:   a sixth switch and a seventh switch that are connected in series between the input terminal of the input voltage and the input node of the current generator, the sixth switch and the seventh switch also being connected in parallel to the first switch and the second switch between a first node, which is provided between the input terminal of the input voltage and the first switch, and a second node, which is provided between the second switch and the input node of the current generator; and   a third capacitor, one end of which is connected between the sixth switch and the seventh switch.   
     
     
         11 . The voltage to current converter according to  claim 10 , wherein
 the first switch and the seventh switch are synchronized and turned on or off,   the second switch and the sixth switch are synchronized and turned on or off,   the second switch and the sixth switch are turned on during a period in which the first switch and the seventh switch are off, and   the second switch and the sixth switch are turned off during a period in which the first switch and the seventh switch are on.   
     
     
         12 . The voltage to current converter according to  claim 1 , wherein
 the first switch is connected between the input terminal of the input voltage and the one end of the first capacitor,   the second switch is connected between the one end of the first capacitor and the input node of the current generator, and   the charge transfer device comprises:   an eighth switch that is connected between a first node, which is provided between the input terminal of the input voltage and the first switch, and the other end of the first capacitor; and   a ninth switch that is connected between the other end of the first capacitor and a second node, which is provided between the second switch and the input node of the current generator.   
     
     
         13 . The voltage to current converter according to  claim 12 , wherein
 the first switch and the ninth switch are synchronized and turned on or off,   the second switch and the eighth switch are synchronized and turned on or off,   the second switch and the eighth switch are turned on during a period in which the first switch and the ninth switch are off, and   the second switch and the eighth switch are turned off during a period in which the first switch and the ninth switch are on.