CMOS differential buffer circuit
AssigneeTexas Instruments Incorporated
InventorRanjit Gharpurey
Life of this patent
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Abstract
The present invention pertains to a MOS type differential buffer circuit. The buffer proposed herein utilizes capacitive coupling to apply small AC signals to an amplifying current source to mitigate attenuation owing to body effect and output impedance, among other things, in an associated follower component. The proposed circuit does not, however, promote an increase in current and/or power dissipation. Additionally, the circuit allows a desired gain to be achieved while maintaining a relatively constant output impedance, compared to a simple differential source follower.
Claims19
A MOS type differential buffer circuit, comprising:
- a current mirror;
- an amplifier current source operatively coupled to the current mirror to receive a bias voltage there-from;
- first and second input bias circuits;
- first and second differential input nodes;
- a source follower operatively coupled to the first and second input bias circuits and the first and second differential input nodes to respectively receive bias signals and small AC signals there-from;
- and
- small signal passage components coupled between the first and second differential input nodes and the amplifier current source, the small signal passage components allowing the respective small AC signals to pass there-through and be applied to the amplifier current source, the amplifier current source being operatively coupled to the source follower to provide current thereto, the small AC signals applied to the amplifier current source serving to mitigate attenuation experienced in the source follower.
Dependencies are inferred from the claim text.