Temperature-compensated ring oscillator

A temperature-compensated ring oscillator, comprising:

• a control signal generator configured to generate at least one control signal, the control signal generator comprising:
• at least one first resistor having a first end which receives a reference voltage and a second end;
• and
• at least one second resistor having a third end coupled to the second end of the first resistor, wherein the control signal is extracted from the third end of the second resistor, the first resistor and the second resistor respectively having a first temperature coefficient and a second temperature coefficient, wherein the first temperature coefficient is negative, and the second temperature coefficient is positive;
• and
• a voltage controlled oscillator receiving the control signal from the third end of the second resistor and outputting an oscillation signal, the voltage controlled oscillator having three inverter units, each of the inverter units comprising:
• a first transistor having a drain coupled to a first supply voltage and a gate to receive the control signal;
• a second transistor having a source to receive a second supply voltage and a gate to receive the control signal;
• and
• an inverter coupled between the first transistor and the second transistor, wherein an output port of the 1st inverter is connected to an input port of the 2nd inverter, an output port of the 2nd inverter is connected to an input port of the 3rd inverter, and an output port of the 3rd inverter is connected to an input port of the 1st inverter.

A temperature-compensated ring oscillator, comprising:

• a control signal generator configured to generate 4 control signals, the control signal generator comprising 4 resistor modules, wherein the xth resistor module comprises:
• a first resistor having a first end which receives a reference voltage and a second end;
• and
• a second resistor having a third end coupled to the second end of the first resistor, wherein the xth control signal is extracted from the third end of the second resistor, the first resistor and the second resistor respectively having a first temperature coefficient and a second temperature coefficient, wherein the first temperature coefficient is negative, and the second temperature coefficient is positive, and x is an integer from 1 to 4;
• and
• a voltage controlled oscillator receiving the control signal and outputting an oscillation signal, the voltage controlled oscillator having (2k+1) cascaded inverter units, where k≧1, each of the inverter units comprising:
• a first transistor having a drain coupled to a first supply voltage and a gate to receive the 1st control signal;
• a second transistor having a source to receive a second supply voltage and a gate to receive the 2nd control signal;
• an inverter coupled between the first transistor and the second transistor;
• a third transistor having a gate to receive the 3rd signal, and a source coupled to the output port of the inverter;
• and
• a fourth transistor having a gate coupled to a drain of the third transistor, a source and a drain coupled to each other to receive the 4th control signal,
• wherein the gate of the fourth transistor in the jth inverter unit is connected to an input port of the (j+1)th inverter unit, where j is an integer from 1 to 2k, and the gate of the fourth transistor in the (2k+1)th inverter unit is connected to an input port of the 1st inverter unit.

A temperature-compensated ring oscillator, comprising:

• a control signal generator configured to generate at least one control signal, the control signal generator comprising:
• at least one first resistor having a first end which receives a reference voltage and a second end;
• and
• at least one second resistor having a third end coupled to the second end of the first resistor, wherein the control signal is extracted from the third end of the second resistor, the first resistor and the second resistor respectively having a first temperature coefficient and a second temperature coefficient, wherein an absolute value of the first temperature coefficient is smaller than an absolute value of the second temperature coefficient;
• and
• a voltage controlled oscillator receiving the control signal and outputting an oscillation signal, the voltage controlled oscillator having (2k+1) cascaded inverter units, where k≧1, each of the inverter units comprising:
• a first transistor having a drain coupled to a first supply voltage and a gate to receive the control signal;
• a second transistor having a source to receive a second supply voltage and a gate to receive the control signal;
• and
• an inverter coupled between the first transistor and the second transistor, wherein an output port of the jth inverter is connected to an input port of the (j+1)th inverter, where j is an integer from 1 to 2k, and an output port of the (2k+1)th inverter is connected to an input port of the 1st inverter.