Patent ID: 8054101

Claim:
An N-bit current source whose output current is controlled by an N-bit input code, wherein N is a predetermined positive integer, when N is equal to one, the N-bit current source comprises: a first current branch; and a second current branch coupled in parallel with the first current branch between a voltage terminal and an output terminal; when N is greater than one, the N-bit current source comprises: a first (N−1)-bit current source whose output current is controlled by the N−1 LSBs of the input code; a second (N−1)-bit current source whose output current is controlled by the N−1 LSBs of the input code, wherein the first and the second (N−1)-bit current sources are coupled in parallel between the voltage terminal and the output terminal; and a switch device coupled in series with each of the current branches of the second (N−1)-bit current source between the voltage terminal and the output terminal.