Voltage converter with auto-isolation function

Abstract

The disclosure relates to a voltage converter, converting a first signal of a first voltage to output a second signal of a second voltage. A level shifter receives the first signal to generate the second signal. An isolation circuit is coupled to the output of the level shifter, passing the second signal out. When the input of voltage converter is floated, the isolation circuit stops passing the second signal as the output, instead, the isolation circuit outputs a substitution signal having a predetermined voltage level irrelevant to the input of the level shifter.

1 - 14 . (canceled) 
   
   
       15 . A voltage converter for converting a first signal of a first voltage into a second signal of a second voltage, comprising:
 a level shifter, further comprising:
 an input terminal, for inputting the first signal; 
 an output terminal, for outputting the second signal; and 
   a first inverter, comprising:
 an output; and 
 an input, coupled to the output terminal; and 
   an isolation circuit, for feeding the output of the first inverter back to the input of the first inverter;   wherein:   the level shifter dominates the output terminal of the level shifter to output the second signal via the first inverter when the input terminal of the level shifter is not floating; and   the isolation circuit integrates the first inverter of the level shifter to form a latch circuit to continue outputting a previous state of the second signal as a substitution signal of the second signal when the input terminal of level shifter is floating.   
   
   
       16 . A voltage converter as claimed in  claim 15 , wherein the isolation circuit comprises an inverter, wherein the inverter comprises an input end coupled to the output of the first inverter of the level shifter and an output end coupled to the input of the first inverter of the level shifter. 
   
   
       17 . A voltage converter for converting a first signal of a first voltage into a second signal of a second voltage, comprising:
 a level shifter, for outputting the second signal when an input terminal of the level shifter is not floating; and   a latch circuit, coupled to an output terminal of the level shifter, for automatically outputting a previous state of the second signal as a substitution signal of the second signal when the input terminal of level shifter is floating.   
   
   
       18 . A voltage converter as claimed in  claim 17 , wherein the latch circuit comprises:
 an first inverter, further comprising:
 a first input, coupled to the output terminal of the level shifter; and 
 a first output; and 
   an second inverter, further comprising:
 a second input, coupled to the first output of the first inverter; and 
 a second output, coupled to the first input of the first inverter.