Low voltage, fast settling precision current mirrors
AssigneeMaxim Integrated Products, Inc.
InventorGabriel E. Tanase
Life of this patent
Estimating the term…
Abstract
Low voltage, fast settling precision current mirrors and methods. The precision current mirror have first and second current mirrors, each having an input to be mirrored and a mirror output, the current mirrors being coupled so that the mirror output of each current mirror receives part of the input to be mirrored by the other current mirror, the first current mirror also mirroring current for re-mirroring to the input of the second current mirror, and to a precision current mirror output in proportion to the current provided to the input of the second current mirror. Various embodiments are disclosed, including MOS and junction transistor embodiments, and an embodiment having increased output impedance. Details of the method are disclosed.
Claims18
A current mirror comprising:
- first through fifth semiconductor devices and an output current control circuit;
- a first component of the current to be mirrored being coupled to a common connection of the first and fourth semiconductor devices;
- a second component of the current to be mirrored being coupled to a common connection of the third and fifth semiconductor devices;
- the current in the first device being mirrored to the second and third semiconductor devices;
- the current in the fifth semiconductor device being mirrored to the fourth semiconductor device;
- the output current control circuit having one output coupled to the common connection of the third and fifth semiconductor devices and responsive to the current in the second semiconductor device to mirror the current in the second semiconductor device to the fifth and third semiconductor devices and to a current mirror output.
A method of mirroring current comprising:
- coupling a first component of the current to be mirrored to a common connection of first and fourth semiconductor devices;
- coupling a second component of the current to be mirrored to a common connection of third and fifth semiconductor devices;
- mirroring the current in the first device to second and third semiconductor devices;
- mirroring the current in the fifth semiconductor device to the fourth semiconductor device;
- and,
- mirroring the current in the second semiconductor device to the common connection of the fifth and third semiconductor devices and to a current mirror output.
A precision current mirror comprising first and second current mirrors, each having an input to be mirrored and a mirror output, the current mirrors being coupled so that the mirror output of each current mirror receives part of the input to be mirrored by the other current mirror, the first current mirror also mirroring current for re-mirroring to provide part of the input of the second current mirror, and to a precision current mirror output in proportion to the current provided to the input of the second current mirror.
A method of mirroring current comprising:
- providing a first current to be mirrored to a first current mirror and as part of the output of a second current mirror;
- providing a second current to be mirrored to a second current mirror and as part of the output of a first current mirror;
- and also,
- mirroring current of the first current mirror to the input of the second current mirror, and to a precision current mirror output in proportion to the current provided to the input of the second current mirror.
Dependencies are inferred from the claim text.