Resistorless VCO including current source and sink controlling a current controlled oscillator
First Claim
Patent Images
1. A resistorless voltage controlled oscillator comprising:
- a capacitor comprising a first terminal and a second terminal, the first terminal receiving an input voltage level, the second terminal receiving a first voltage supply;
a first transistor comprising a first current electrode, a second current electrode and a control electrode, the first current electrode receiving the first voltage supply, the control electrode coupled to the first terminal of the capacitor, the second terminal coupled to an intermediate node;
a current sourcing circuit coupled to the intermediate node, the current sourcing circuit sourcing current to the intermediate node responsive to a first control signal;
a current sinking circuit coupled to the intermediate node, the current sinking circuit sinking current from the intermediate node responsive to a second control signal; and
a current controlled oscillator coupled to the intermediate node, the current controlled oscillator generating a periodic clocking signal responsive to the current sourced at the intermediate node.
18 Assignments
0 Petitions
Accused Products
Abstract
A voltage controlled oscillator (VCO) 16 generates a periodic clock signal without the use any resistors. Therefore, the described VCO may be advantageously incorporated into devices fabricated with semiconductor processes without special resistor-base design constraints.
30 Citations
18 Claims
-
1. A resistorless voltage controlled oscillator comprising:
-
a capacitor comprising a first terminal and a second terminal, the first terminal receiving an input voltage level, the second terminal receiving a first voltage supply; a first transistor comprising a first current electrode, a second current electrode and a control electrode, the first current electrode receiving the first voltage supply, the control electrode coupled to the first terminal of the capacitor, the second terminal coupled to an intermediate node; a current sourcing circuit coupled to the intermediate node, the current sourcing circuit sourcing current to the intermediate node responsive to a first control signal; a current sinking circuit coupled to the intermediate node, the current sinking circuit sinking current from the intermediate node responsive to a second control signal; and a current controlled oscillator coupled to the intermediate node, the current controlled oscillator generating a periodic clocking signal responsive to the current sourced at the intermediate node. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
-
10. A system comprising:
-
a phase/frequency detector receiving a reference clock signal and a feedback clock signal, the phase/frequency detector generating a first control signal and a second control signal responsive to a phase and frequency relationship of the reference clock signal and a feedback clock signal; a charge pump coupled to the phase/frequency detector, the charge pump generating an output voltage responsive to the first and second control signals; a voltage controlled oscillator coupled to the charge pump and to the phase/frequency detector, the voltage controlled oscillator generating the feedback clock signal, the voltage controlled oscillator comprising; a capacitor comprising a first terminal and a second terminal, the first terminal receiving said output voltage, the second terminal receiving a first voltage supply; a first transistor comprising a first current electrode, a second current electrode and a control electrode, the first current electrode receiving the first voltage supply, the control electrode coupled to the first terminal of the capacitor, the second terminal coupled to an intermediate node; a current sourcing circuit coupled to the intermediate node, the current sourcing circuit sourcing current to the intermediate node responsive to the first control signal; a current sinking circuit coupled to the intermediate node, the current sinking circuit sinking current from the intermediate node responsive to the second control signal; and a current controlled oscillator coupled to the intermediate node, the current controlled oscillator generating the feedback clock signal responsive to the current sourced at the intermediate node. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
-
Specification