Low-noise programmable current source
First Claim
Patent Images
1. A low-noise programmable current source comprising;
- an output digital to analog converter for providing an output load current; and
a control circuit, responsive to an input defining a predetermined load current, for generating for said digital to analog converter, a control word and a control voltage, said control word and control voltage driving said digital to analog converter to produce said predetermined load current and said control voltage setting the compliance voltage of said digital to analog converter to minimize current noise in said digital to analog converter.
1 Assignment
0 Petitions
Accused Products
Abstract
A low-noise programmable current source includes an output digital to analog converter for providing an output load current; and a control circuit, responsive to an input defining a predetermined load current for generating, for the digital to analog converter, a control word and a control voltage; the control word and the control voltage drive the digital to analog converter to produce the predetermined load current and the control voltage sets the compliance voltage of the digital to analog converter to minimize current noise in the digital to analog converter.
20 Citations
30 Claims
-
1. A low-noise programmable current source comprising;
-
an output digital to analog converter for providing an output load current; and a control circuit, responsive to an input defining a predetermined load current, for generating for said digital to analog converter, a control word and a control voltage, said control word and control voltage driving said digital to analog converter to produce said predetermined load current and said control voltage setting the compliance voltage of said digital to analog converter to minimize current noise in said digital to analog converter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
-
-
29. A voltage controlled oscillator (VCO) system having a low-noise programmable current source comprising:
-
an output digital to analog converter for providing an output load current to the VCO; and a control circuit responsive to an input defining a predetermined load current for the VCO for generating, for the digital to analog converter, a control word and a control voltage, said control word and control voltage driving said digital to analog converter to produce said predetermined load current for said VCO, said control voltage setting the compliance voltage of said digital to analog converter to substantially minimize current noise in the digital to analog Converter and phase noise in the VCO.
-
-
30. A low-noise programmable current source comprising;
-
an output digital to analog converter for providing an output load current; and a control circuit, responsive to a load voltage and an input defining a predetermined load current, for generating for said digital to analog converter, a control word and a control voltage, said control word and control voltage driving said digital to analog converter to produce said predetermined load current and said control voltage setting the compliance voltage of said digital to analog converter to minimize current noise in said digital to analog converter, said control circuit including a comparator responsive to said load voltage and at least said control voltage for determining whether said output digital to analog converter has more headroom than it is using, a digital state machine responsive to said comparator and said input defining a predetermined load current for generating said control word and said control voltage to adjust said compliance voltage.
-
Specification