US 10,892,767 B1
High accuracy matching system and method therefor
Tao Chen, Austin, TX (US); and Robert S. Jones, III, Austin, TX (US)
Assigned to NXP USA, INC., Austin, TX (US)
Filed by NXP USA, INC., Austin, TX (US)
Filed on Sep. 20, 2019, as Appl. No. 16/577,122.
Int. Cl. H03M 1/06 (2006.01); G05F 3/26 (2006.01); H03M 1/12 (2006.01)
CPC H03M 1/066 (2013.01) [G05F 3/267 (2013.01); H03M 1/1245 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A circuit comprising:
an analog to digital converter (ADC) configured to generate an output code;
a current source configured to provide an input signal to the ADC, the current source comprising:
a first current branch including a first unit element group, the first unit element group comprising a first unit element coupled by way of a first set of switches to a first node and a second node and a second unit element coupled by way of a second set of switches to the first node and the second node; and
a second current branch including a second unit element group, the second unit element group comprising a third unit element coupled by way of a third set of switches to the first node and the second node and a fourth unit element coupled by way of a fourth set of switches to the first node and the second node; and
a control circuit configured to provide control signals to the sets of switches based on the output code, the control circuit further configured to sort unit element currents and to dynamically switch unit elements during an element matching operation, wherein the output code is used to sort the unit element currents based on a relationship between a current ratio and the output code.