Semiconductor circuits, devices and methods

Abstract

A high-voltage sensing device providing full galvanic isolation between a high-voltage domain and a low-voltage domain, wherein the circuit topology of the device resembles that of a Wheatstone bridge, the Wheatstone bridge employing at least one voltage-controlled semiconductor resistor, wherein the circuit also comprises a reference source connected directly to the Wheatstone bridge and the device comprises a number of shielding structures to electrically isolate the high-voltage domain from the low-voltage domain.

1 . A circuit for sensing an input voltage, the circuit providing an output, the circuit comprising:
 a first series combination of first and second voltage-controlled semiconductor resistors, the first series combination being connected in parallel with a second series combination of third and fourth voltage-controlled semiconductor resistors, wherein each voltage-controlled semiconductor resistor includes a gate, and wherein the first voltage-controlled semiconductor resistor is connected directly to the third voltage-controlled semiconductor resistor; and   a reference source; wherein:   the reference source is connected to the first series combination and also to the second series combination;   the gates of the second and third voltage-controlled semiconductor resistors are held equipotential by means of an electrical interconnector;   the gate of the first voltage-controlled resistor and said electrical interconnector are provided with respective connectors for applying the input voltage therebetween; and   the output is arranged to be derived from either:   a) a potential difference between:
 i) a first point between the first and second voltage-controlled semiconductor resistors, and 
 ii) a second point between the third and fourth voltage-controlled semiconductor resistors; or 
   b) a current flowing between:
 i) a first point between the first and second voltage-controlled semiconductor resistors, and 
 ii) a second point between the third and fourth voltage-controlled semiconductor resistors. 
   
     
     
         2 . A circuit for sensing an input voltage, the circuit providing an output, the circuit comprising:
 a first series combination of first and second resistors, the first series combination being connected in parallel with a second series combination of third and fourth resistors, wherein the first resistor is connected directly to the third resistor; and   a reference source; wherein:   the reference source is connected to the first series combination and also to the second series combination;   the first resistor is a voltage-controlled semiconductor resistor including a gate;   the second and fourth resistors are connected by means of an electrical interconnector;   the gate of the first voltage-controlled resistor and said electrical interconnector are provided with respective connectors for applying the input voltage therebetween; and   the output is arranged to be derived from either:   a) a potential difference between:
 i) a first point between the first and second resistors, and 
 ii) a second point between the third and fourth resistors; or 
   b) a current flowing between:
 i) a first point between the first and second resistors, and 
 ii) a second point between the third and fourth resistors. 
   
     
     
         3 . The circuit according to  claim 2 , wherein more than one of said first, second, third and fourth resistors are voltage-controlled semiconductor resistors. 
     
     
         4 . The circuit according to  claim 1 , wherein the reference source is a reference voltage source or a reference current source. 
     
     
         5 . The circuit according to  claim 1 , wherein the circuit can withstand said input voltage having any magnitude in the range 0-2500V. 
     
     
         6 . The circuit according to  claim 1 , further comprising a differential amplifier, wherein one of the inputs of the differential amplifier is connected to said first point and the other one of the inputs of the differential amplifier is connected to said second point, the output of the differential amplifier providing said output. 
     
     
         7 . A power meter utilizing the circuit according to  claim 1  and a current sensor. 
     
     
         8 . The power meter according to  claim 7 , wherein the current sensor is a Hall-effect current sensor. 
     
     
         9 . A method of determining a measure indicative of a voltage, the method utilizing a circuit comprising a Wheatstone bridge, the Wheatstone bridge comprising a number of resistors and a reference source, wherein at least one of the resistors of the Wheatstone bridge is a voltage-controlled semiconductor resistor. 
     
     
         10 . The method according to  claim 9 , wherein determining the measure indicative of the voltage comprises generating an output voltage of the circuit, wherein the magnitude of the output voltage of the circuit used for determining said voltage is less than 10V. 
     
     
         11 . The method according to  claim 9 , wherein determining the measure indicative of the voltage comprises generating an output current of the circuit. 
     
     
         12 . The method according to  claim 9 , wherein the circuit can withstand said voltage having any magnitude in the range 0-2500V, 
     
     
         13 . The method according to  claim 9 , wherein the circuit draws substantially no power from a source providing said voltage. 
     
     
         14 . A Wheatstone bridge comprising a number of resistors, wherein at least one of the resistors of the Wheatstone bridge is a voltage-controlled semiconductor resistor. 
     
     
         15 . The circuit according to  claim 1 , wherein at least one of the one or more voltage-controlled semiconductor resistors is a voltage-controlled semiconductor well resistor.