Claims
- 1. An amplifier circuit, comprising:
- a first amplifier stage having
- a first pair of input transistors having control electrodes arranged to receive an input signal and current electrodes coupled at a first common node,
- a pair of first outputs configured to emit a first output signal from the first amplifier stage, and
- at least one first current-source load coupled to at least one of the pair of first outputs, the current-source load generating a substantially constant amount of current regardless of changes in a voltage present at the at least one of the pair of first outputs;
- a second amplifier stage having
- a second pair of input transistors having current electrodes coupled at a second common node and each of the second pair of input transistors having a control electrode coupled to a respective one of the pair of first outputs to receive the first output signal from the first amplifier stage,
- at least one second output to emit a second output signal from the second amplifier stage, and
- at least one second current-source load coupled to the at least one second output, the current-source load generating a substantially constant amount of current regardless of changes in a voltage present at the at least one second output;
- wherein all transistors in a feedforward signal path extending between the control electrodes of the first pair of input transistors and the at least one second output are of a common doping type.
- 2. The amplifier circuit as claimed in claim 1, further comprising a first common-mode control network configured to control a common-mode level of the first amplifier stage based at least in part on the first output signal.
- 3. The amplifier circuit as claimed in claim 2, wherein the second amplifier stage includes a current-source coupled to the second common node.
- 4. The amplifier circuit as claimed in claim 2, further comprising, a second common-mode control network configured to control a common-mode level of the second amplifier stage based at least in part upon the second output signal.
- 5. The amplifier circuit as claimed in claim 1, further comprising a common-mode control network configured to control a common-mode level of the second amplifier stage based at least in part upon the second output signal.
- 6. The amplifier circuit as claimed in claim 5, wherein the second amplifier stage includes a current-source coupled to the second common node.
- 7. The amplifier circuit as claimed in claim 1, further comprising a common-mode control network configured to control a common-mode level of both the first and second amplifier stages based at least in part upon the second output signal.
- 8. The amplifier circuit as claimed in claim 1, wherein the first amplifier stage includes a first current-source coupled to the first common node.
- 9. The amplifier circuit as claimed in claim 8, wherein the second amplifier stage includes a second current-source coupled to the second common node.
- 10. The amplifier circuit as claimed in claim 1, wherein the second amplifier stage includes a current-source coupled to the second common node.
- 11. The amplifier circuit as claimed in claim 1, wherein:
- the first current-source load includes a first current-source transistor having a control electrode and first and second current electrodes, the first current electrode of the first current-source transistor being coupled to the at least one of the pair of first outputs, and the first current-source transistor being arranged such that a voltage presented between the control electrode and the second current electrode of the first current-source transistor is primarily responsible for determining an amount of current that flows between the first and second current electrodes of the first current-source transistor; and
- the second current-source load includes a second current-source transistor having a control electrode and first and second current electrodes the first current electrode of the second current-source transistor being coupled to the at least one second output, and the second current-source transistor being arranged such that a voltage presented between the control electrode and the second current electrode of the second current-source transistor is primarily responsible for determining an amount of current that flows between the first and second current electrodes of the second current-source transistor.
- 12. An amplifier circuit comprising:
- a first amplifier stage having
- at least one first input to receive an input signal,
- at least one first output to emit a first output signal, and
- at least one first current-source load coupled to the at least one first output, the at least one first current-source load generating a substantially constant amount of current regardless of changes in a voltage present at the at least one first output; and
- a second amplifier stage having
- at least one second input coupled to the at least one first output to receive the first output signal from the first amplifier stage, each output of the first amplifier stage being coupled to a respective input of the second amplifier stage,
- at least one second output to emit a second output signal, and
- at least one second current-source load coupled to the at least one second output, the at least one second current-source load generating a substantially constant amount of current regardless of changes in a voltage present at the at least one second output;
- wherein all transistors included in a feedforward signal path extending between the at least one first input and the at least one second output are of a common doping type.
- 13. The amplifier circuit as claimed in claim 12, further comprising a first common-mode control network configured to control a common-mode level of the first amplifier stage based at least in part on the first output signal.
- 14. The amplifier circuit as claimed in claim 13, further comprising a second common-mode control network configured to control a common-mode level of the second amplifier stage based at least in part upon the second output signal.
- 15. The amplifier circuit as claimed in claim 12, further comprising a common-mode control network configured to control a common-mode level of the second amplifier stage based at least in part upon the second output signal.
- 16. The amplifier circuit as claimed in claim 12, further comprising a common-mode control network configured to control a common-mode level of both the first and second amplifier stages based at least in part upon the second output signal.
- 17. The amplifier circuit as claimed in claim 12, wherein:
- the first current-source load includes a first current-source transistor having a control electrode and first and second current electrodes, the first current electrode of the first current-source transistor being coupled to the at least one first output, and the first current-source transistor being arranged such that a voltage presented between the control electrode and the second current electrode of the first current-source transistor determines an amount of current that flows between the first and second current electrodes of the first current-source transistor; and
- the second current-source load includes a second current-source transistor having a control electrode and first and second current electrodes, the first current electrode of the second current-source transistor being coupled to the at least one second output and the second current-source transistor being arranged such that a voltage presented between the control electrode and the second current electrode of the second current-source transistor determines an amount of current that flows between the first and second current electrodes of the second current-source transistor.
- 18. The amplifier circuit as claimed in claim 12, wherein the first amplifier stage includes a first differential amplifier stage.
- 19. The amplifier circuit as claimed in claim 18, wherein the second amplifier stage includes a second differential amplifier stage.
- 20. The amplifier circuit as claimed in claim 12, wherein the second amplifier stage includes a differential amplifier stage.
Parent Case Info
This is a continuation of application Ser No. 08/654,349, filed May 28, 1996, Pat. No. 5,838,199.
US Referenced Citations (12)
Foreign Referenced Citations (1)
Number |
Date |
Country |
0 320 471A2 |
Jun 1989 |
EPX |
Continuations (1)
|
Number |
Date |
Country |
Parent |
654349 |
May 1996 |
|