Low supply voltage relaxation oscillator having current mirror transistors supply for capacitors
DCFirst Claim
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1. A low supply voltage oscillator circuit comprising:
- a first capacitor and a second capacitor to be controlled, each connected between first and second voltage references; and
a circuit for charging and discharging said capacitors to be controlled, including;
at least first and second stages having symmetrical structures in a mirror-image configuration and being connected between the first voltage reference and the second voltage reference;
a memory element that connects the first and second stages together and has first and second inputs;
first and second primary switches for alternately charging in a controlled fashion said capacitors, the first and second primary switches being connected respectively to the first and second capacitors at first and second connection nodes, respectively; and
first and second secondary switches coupled respectively between the second voltage reference and the first and second inputs of the memory element, the first secondary switch having a control terminal coupled to the first connection node, and the second secondary switch having a control terminal coupled to the second connection node.
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Abstract
Presented is a low supply voltage oscillator circuit having at least one capacitor to be controlled, connected between first and second voltage references, and a circuit for charging and discharging the capacitor to be controlled. The oscillator circuit also includes at least first and second stages having symmetrical structures in a mirror-image configuration and being connected between the first voltage reference and the second voltage reference and connected together through a memory element. The oscillator circuit also includes respective primary switches for alternately charging the capacitors in a controlled fashion.
90 Citations
17 Claims
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1. A low supply voltage oscillator circuit comprising:
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a first capacitor and a second capacitor to be controlled, each connected between first and second voltage references; and
a circuit for charging and discharging said capacitors to be controlled, including;
at least first and second stages having symmetrical structures in a mirror-image configuration and being connected between the first voltage reference and the second voltage reference;
a memory element that connects the first and second stages together and has first and second inputs;
first and second primary switches for alternately charging in a controlled fashion said capacitors, the first and second primary switches being connected respectively to the first and second capacitors at first and second connection nodes, respectively; and
first and second secondary switches coupled respectively between the second voltage reference and the first and second inputs of the memory element, the first secondary switch having a control terminal coupled to the first connection node, and the second secondary switch having a control terminal coupled to the second connection node. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A low supply voltage oscillator circuit, comprising:
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a first capacitor connected between first and second voltage references;
a first primary switch coupled to the first capacitor and structured to discharge a charge stored in the first capacitor when a control terminal of the first primary switch receives a first control signal;
a memory element having a first input and a first output coupled to the control terminal of the first primary switch, the memory element being structured to generate the first control signal at the first output based on a state at the first input; and
a current mirror circuit that includes;
a current generator;
a first mirror transistor connected with the current generator between the first and second voltage references;
a second mirror transistor connected with the first capacitor between the first and second voltage references and having a control terminal connected to a control terminal of the first mirror transistor; and
a third mirror transistor connected between the first voltage reference and the first input of the memory element and having a control terminal connected to the control terminal of the first mirror transistor. - View Dependent Claims (12, 13, 14, 15, 16, 17)
a second capacitor connected between the first and second voltage references;
a second primary switch coupled to the second capacitor and structured to discharge a charge stored in the second capacitor when a control terminal of the second primary switch receives the second control signal.
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14. The oscillator circuit of claim 13 wherein the current mirror circuit includes a fourth mirror transistor connected between the first voltage reference and a second input of the memory element and having a control terminal connected to the control terminal of the first mirror transistor.
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15. The oscillator circuit of claim 14 wherein the current mirror circuit includes a fifth mirror transistor coupled with the second capacitor between the first and second voltage references and having a control terminal connected to the control terminal of the first mirror transistor.
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16. The oscillator circuit of claim 11 wherein the current generator includes:
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a first transistor and a resistive element connected in series between the first mirror transistor and the second voltage reference;
a fourth mirror transistor connected in a current mirror configuration with the first mirror transistor; and
a second transistor connected with the fourth mirror transistor between the first and second voltage references.
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17. The oscillator circuit of claim 16 wherein the first transistor has a control terminal connected to an interconnection node between the fourth mirror transistor and the second transistor, the second transistor having a control terminal connected to an interconnection node between the first transistor and the resistive element.
Specification