Amplifier with actively clamped load
AssigneeTexas Instruments Incorporated
InventorAswin N. Mehta
Life of this patent
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Abstract
An amplifier is arranged with an actively clamped load. In a differential amplifier, a pair of emitter-coupled transistors has loads connected between the collectors and a voltage supply. Separate clamping transistors have their collector-emitter paths connected across respective ones of the loads. A clamping control circuit, responsive to an input signal, produces a variable control signal to clamp output signal swings across the loads. A similar clamping control circuit can be used with a single-ended amplifier. Such an amplifier having an actively clamped load is useful in sense amplifier circuit arrangements in semiconductor memory arrangements used in data processing systems.
Claims19
A differential amplifier comprising:
- first and second emitter-coupled transistors;
- a current source connected between the emitters of the first and second emitter-coupled transistors and a reference potential;
- first and second loads are connected between the respective collector electrodes of the first and second emitter-coupled transistors and a voltage supply;
- first and second clamping transistors, each has its collector-emitter path connected across a respective one of the loads;
- and
- a clamping control circuit, responsive to an input signal, for producing and applying to base electrodes of the first and second clamping transistors variable control signals to clamp output signal swings at various levels across the first and second loads.
An amplifier comprising:
- a first transistor having an emitter electrode coupled to a reference potential;
- a load connected between a collector electrode of the first transistor and a voltage supply;
- a clamping transistor having a collector-emitter path connected across the load;
- and
- a clamping control circuit, responsive to a D.C. voltage level and to a magnitude of an input control signal, for producing a variable magnitude control signal, applied to a gate electrode of the clamping transistor, to cause signal swings to be clamped at various levels across the load.
Dependencies are inferred from the claim text.