Patent ID: 8149021

Claim:
A current detection circuit comprising: a main switch circuit capable of passing an output current received from a power source circuit to a load, a first auxiliary switch circuit connected to one terminal of said main switch circuit and a first terminal, and generating a first auxiliary detection current being smaller than said output current and approximately proportional to said output current when turned ON, a second auxiliary switch circuit connected to the other terminal of said main switch circuit and a second terminal, and generating a second auxiliary detection current being smaller than said output current and approximately proportional to said output current when turned ON, and a current adjustment detection circuit, wherein said current adjustment detection circuit includes a first adjustment circuit, a second adjustment circuit and a detection current generating circuit, said first adjustment circuit adjusts said first auxiliary detection current so that said other terminal and said first terminal have the same potential and passes said first auxiliary detection current in a direction of receiving said adjusted first auxiliary detection current from said first auxiliary switch circuit, said second adjustment circuit adjusts said second auxiliary detection current so that said one terminal and said second terminal have the same potential and passes said adjusted second auxiliary detection current in a direction of outputting said second auxiliary detection current to said adjusted second auxiliary switch circuit, and said detection current generating circuit generates a detection current being smaller than said output current and approximately proportional to said output current on the basis of said adjusted first detection current and said adjusted second detection current.