Current comparator using wide swing current mirrors
AssigneeAeroflex Colorado Springs Inc.
InventorKevin Ryan
Life of this patent
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Abstract
A current comparator includes an input node for receiving an input current, an output node, a first wide swing current mirror having an input coupled to the input node of the current comparator, a power node for receiving a first power supply voltage such as ground, and an output coupled to the output node of the current comparator, and a second wide swing current mirror having an input coupled to the input node of the current comparator, a power node for receiving a second power supply voltage such as VDD, and an output coupled to the output node of the current comparator. The output node can provide either a voltage or current output signal.
Claims15
A current comparator, comprising:
- an input node for receiving an input current;
- an output node;
- a first wide swing current mirror comprising:
- an input coupled to the input node of the current comparator, a power node for receiving a first power supply voltage, and an output coupled to the output node of the current comparator, wherein the first wide swing current mirror comprises a first N-channel transistor directly coupled to the first power supply voltage, a gate directly coupled to the input node of the current comparator, and a drain;
- a second N-channel transistor directly coupled to the first power supply voltage, a gate coupled to the gate of the first N-channel transistor, and a drain;
- a third N-channel transistor having a source directly coupled to the drain of the first N-channel transistor, a gate coupled to a bias node, and a drain coupled to the input node of the current comparator;
- a fourth N-channel transistor having a source directly coupled to the drain of the second N-channel transistor, a gate coupled to the bias node, and a drain coupled to the output node of the current comparator;
- and
- a second wide swing current mirror formed using P-channel transistors comprising an input coupled to the input node of the current comparator, a power node for receiving a second power supply voltage, and an output coupled to the output node of the current comparator.
A current comparison method, comprising:
- providing a first wide swing current mirror comprising:
- an input coupled to an input node of a current comparator, a power node for receiving a first power supply voltage, and an output coupled to an output node of the current comparator, wherein the first wide swing current mirror comprises a first N-channel transistor having a source directly coupled to the first power supply voltage, a gate directly coupled to the input node of the current comparator, and a drain;
- a second N-channel transistor having a source directly coupled to the first power supply voltage, a gate coupled to the gate of the first N-channel transistor, and a drain;
- a third N-channel transistor having a source directly coupled to the drain of the first N-channel transistor, a gate coupled to a bias node, and a drain coupled to the input node of the current comparator;
- a fourth N-channel transistor having a source coupled to the drain of the second N-channel transistor, a gate coupled to the bias node, and a drain coupled to the output node of the current comparator;
- and
- providing a second wide swing current mirror formed using P-channel transistors comprising an input coupled to the input node of the current comparator, a power node for receiving a second power supply voltage, and an output coupled to the output node of the current comparator.
Dependencies are inferred from the claim text.