Semiconductor device

Abstract

A semiconductor device comprises a first current mirror circuit ( 101 ) which has an input terminal ( 101 I) and an output terminal ( 101 O), a second current mirror circuit ( 102 ) which has an input terminal ( 102 I) and an output terminal ( 102 O) wherein the input terminal ( 102 I) is coupled with the output terminal ( 101 O) wherein the output terminal ( 102 O) is coupled with said input terminal ( 101 I) and a start-up circuit ( 103 ) which supplies current to input terminal ( 102 I) based on voltage on the input terminal ( 101 I).

What is claimed is:  
     
         1 . A semiconductor device, comprising: 
 a first node which is provided a first voltage;    a second node which is provided a second voltage, wherein said second voltage is lower than said first voltage;    a first current mirror circuit which has an input terminal and an output terminal, wherein said first current mirror circuit is coupled with said first node;    a second current mirror circuit which has an input terminal and an output terminal, wherein said input terminal of said second current mirror circuit is coupled with said output terminal of said first current mirror circuit, wherein said output terminal of said second current mirror circuit is coupled with said input terminal of said first current mirror circuit and wherein said second current mirror circuit is coupled with said second node;    a start-up circuit which supplies current to said input terminal of said second current mirror circuit based on voltage on said input terminal of said first current mirror circuit.    
     
     
         2 . The semiconductor device in accordance with  claim 1 , wherein said start-up circuit comprises; 
 a third node;    a capacitance element which is coupled between said third node and said second node;    a first switch which has an ON state and an OFF state, and which is coupled between said first node and said input terminal of said second current mirror circuit; and    a second switch which has an ON state and an OFF state, and which is coupled between said first node and said third node.    
     
     
         3 . The semiconductor device in accordance with  claim 2 , wherein said first switch comprises a first transistor which has a control electrode coupling with said third node, a first electrode coupling with said first node and a second electrode coupling with said input terminal of said second current mirror circuit, and wherein said second switch comprises a second transistor which has a control electrode coupling with said input terminal of said first current mirror circuit, a first electrode coupling with said first node and a second electrode coupling with said third node.  
     
     
         4 . The semiconductor device in accordance with  claim 3 , wherein first current mirror circuit has a third transistor which has a first electrode coupling with said first node and a control and a second electrodes coupling with said input terminal thereof, and a fourth transistor which has a first electrode coupling with said first node, a control electrode coupling with said control electrode of said third transistor and a second electrode coupling with said output terminal thereof; and wherein said second current mirror circuit has a fifth transistor which has a first electrode coupling with said second node and a control and a second electrodes coupling with said input terminal thereof, and a sixth transistor which has a first electrode coupling with said second node through a resistor, a control electrode coupling with said control electrode of said fifth transistor and a second electrode coupling with said output terminal thereof.  
     
     
         5 . The semiconductor device in accordance with  claim 3 , wherein first current mirror circuit has a third transistor which has a first electrode coupling with said first node and a control and a second electrodes coupling with said input terminal thereof, and a fourth transistor which has a first electrode coupling with said first node through a resistor, a control electrode coupling with said control electrode of said third transistor and a second electrode coupling with said output terminal thereof; and  
       wherein said second current mirror circuit has a fifth transistor which has a first electrode coupling with said second node and a control and a second electrodes coupling with said input terminal thereof, and a sixth transistor which has a first electrode coupling with said second node, a control electrode coupling with said control electrode of said fifth transistor and a second electrode coupling with said output terminal thereof.  
     
     
         6 . The semiconductor device in accordance with  claim 1 , wherein said start-up circuit comprises; 
 a third node;    a capacitance element which is coupled between said third node and said second node;    a resistor which is coupled with said first node;    a first switch which has an ON state and an OFF state, and which is coupled between said first node and said input terminal of said second current mirror circuit; and    a second switch which has an ON state and an OFF state, and which is coupled between said resistor and said third node.    
     
     
         7 . The semiconductor device in accordance with  claim 6 , wherein said first switch comprises a first transistor which has a control electrode coupling with said third node, a first electrode coupling with said first node and a second electrode coupling with said input terminal of said second current mirror circuit, and wherein said second switch comprises a second transistor which has a control electrode coupling with said input terminal of said first current mirror circuit, a first electrode coupling with said resistor and a second electrode coupling with said third node.  
     
     
         8 . The semiconductor device in accordance with  claim 7 , wherein first current mirror circuit has a third transistor which has a first electrode coupling with said first node and a control and a second electrodes coupling with said input terminal thereof, and a fourth transistor which has a first electrode coupling with said first node, a control electrode coupling with said control electrode of said third transistor and a second electrode coupling with said output terminal thereof; and wherein said second current mirror circuit has a fifth transistor which has a first electrode coupling with said second node and a control and a second electrodes coupling with said input terminal thereof, and a sixth transistor which has a first electrode coupling with said second node through a resistor, a control electrode coupling with said control electrode of said fifth transistor and a second electrode coupling with said output terminal thereof.  
     
     
         9 . The semiconductor device in accordance with  claim 7 , wherein first current mirror circuit has a third transistor which has a first electrode coupling with said first node and a control and a second electrodes coupling with said input terminal thereof, and a fourth transistor which has a first electrode coupling with said first node through a resistor, a control electrode coupling with said control electrode of said third transistor and a second electrode coupling with said output terminal thereof; and  
       wherein said second current mirror circuit has a fifth transistor which has a first electrode coupling with said second node and a control and a second electrodes coupling with said input terminal thereof, and a sixth transistor which has a first electrode coupling with said second node, a control electrode coupling with said control electrode of said fifth transistor and a second electrode coupling with said output terminal thereof.  
     
     
         10 . A semiconductor device, comprising: 
 a first node which is provided a first voltage;    a second node which is provided a second voltage, wherein said second voltage is lower than said first voltage;    a first current mirror circuit which has an input terminal and an output terminal, wherein said first current mirror circuit is coupled with said first node;    a second current mirror circuit which has an input terminal and an output terminal, wherein said input terminal of said second current mirror circuit is coupled with said output terminal of said first current mirror circuit, wherein said output terminal of said second current mirror circuit is coupled with said input terminal of said first current mirror circuit and wherein said second current mirror circuit is coupled with said second node;    a start-up circuit which supplies current to said input terminal of said first current mirror circuit based on voltage on said input terminal of said second current mirror circuit.    
     
     
         11 . The semiconductor device in accordance with  claim 10 , wherein said start-up circuit comprises; 
 a third node;    a capacitance element which is coupled between said first node and said third node;    a first switch which has an ON state and an OFF state, and which is coupled between said second node and said input terminal of said first current mirror circuit; and    a second switch which has an ON state and an OFF state, and which is coupled between said second node and said third node.    
     
     
         12 . The semiconductor device in accordance with  claim 11 , wherein said first switch comprises a first transistor which has a control electrode coupling with said third node, a first electrode coupling with said second node and a second electrode coupling with said input terminal of said first current mirror circuit, and wherein said second switch comprises a second transistor which has a control electrode coupling with said input terminal of said second current mirror circuit, a first electrode coupling with said second node and a second electrode coupling with said third node.  
     
     
         13 . The semiconductor device in accordance with  claim 12 , wherein first current mirror circuit has a third transistor which has a first electrode coupling with said first node and a control and a second electrodes coupling with said input terminal thereof, and a fourth transistor which has a first electrode coupling with said first node, a control electrode coupling with said control electrode of said third transistor and a second electrode coupling with said output terminal thereof; and wherein said second current mirror circuit has a fifth transistor which has a first electrode coupling with said second node and a control and a second electrodes coupling with said input terminal thereof, and a sixth transistor which has a first electrode coupling with said second node through a resistor, a control electrode coupling with said control electrode of said fifth transistor and a second electrode coupling with said output terminal thereof.  
     
     
         14 . The semiconductor device in accordance with  claim 12 , wherein first current mirror circuit has a third transistor which has a first electrode coupling with said first node and a control and a second electrodes coupling with said input terminal thereof, and a fourth transistor which has a first electrode coupling with said first node through a resistor, a control electrode coupling with said control electrode of said third transistor and a second electrode coupling with said output terminal thereof; and  
       wherein said second current mirror circuit has a fifth transistor which has a first electrode coupling with said second node and a control and a second electrodes coupling with said input terminal thereof, and a sixth transistor which has a first electrode coupling with said second node, a control electrode coupling with said control electrode of said fifth transistor and a second electrode coupling with said output terminal thereof.  
     
     
         15 . A semiconductor device, comprising: 
 a first node which is provided a first voltage;    a second node which is provided a second voltage, wherein said second voltage is lower than said first voltage;    a first current mirror circuit which is coupled with said first node;    a second current mirror circuit which is coupled with said second node, wherein said second current mirror circuit is coupled with said first current mirror circuit through a third node and a fourth node;    a start-up circuit which supplies current to said fourth node based on voltage on said third node.    
     
     
         16 . The semiconductor device in accordance with  claim 15 , wherein said start-up circuit comprises; 
 a fifth node;    a capacitance element which is coupled between said fifth node and said second node;    a first switch which has an ON state and an OFF state, and which is coupled between said first node and said fourth node; and    a second switch which has an ON state and an OFF state, and which is coupled between said first node and said fifth node.    
     
     
         17 . The semiconductor device in accordance with  claim 16 , wherein said first switch comprises a first transistor which has a control electrode coupling with said fifth node, a first electrode coupling with said first node and a second electrode coupling with said fourth node, and  
       wherein said second switch comprises a second transistor which has a control electrode coupling with said third node, a first electrode coupling with said first node and a second electrode coupling with said fifth node.  
     
     
         18 . The semiconductor device in accordance with  claim 17 , wherein first current mirror circuit has a third transistor which has a first electrode coupling with said first node and a control and a second electrodes coupling with said third node, and a fourth transistor which has a first electrode coupling with said first node, a control electrode coupling with said control electrode of said third transistor and a second electrode coupling with said fourth node; and  
       wherein said second current mirror circuit has a fifth transistor which has a first electrode coupling with said second node and a control and a second electrodes coupling with said fourth node, and a sixth transistor which has a first electrode coupling with said second node through a resistor, a control electrode coupling with said control electrode of said fifth transistor and a second electrode coupling with said third node.  
     
     
         19 . The semiconductor device in accordance with  claim 17 , wherein first current mirror circuit has a third transistor which has a first electrode coupling with said first node and a control and a second electrodes coupling with said third node, and a fourth transistor which has a first electrode coupling with said first node through a resistor, a control electrode coupling with said control electrode of said third transistor and a second electrode coupling with said fourth node; and wherein said second current mirror circuit has a fifth transistor which has a first electrode coupling with said second node and a control and a second electrodes coupling with said fourth node, and a sixth transistor which has a first electrode coupling with said second node, a control electrode coupling with said control electrode of said fifth transistor and a second electrode coupling with said third node.