Bipolar-plus-DMOS mixed-typology power output stage
AssigneeSGS-Thomson Microelectronics S.A.
InventorsCarlo Cini, Fabrizio Stefani
Life of this patent
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Abstract
An output power stage which includes a PNP pull-up transistor and an n-channel FET push-down transistor, driven in phase opposition. This fully complementary stage provides an outstandingly improved power handling capability per semiconductor area occupied, together with a large output voltage swing, but does not require the use of externally connected discrete boot-strap components. The bipolar pull-up transistor can optionally be driven through an FET auxiliary stage, to minimize the power requirements of the preceding signal amplification stage.
Claims14
An integrated power audio output stage comprising:
- a pair of transistors connected, in series with an output node, between a positive and a negative supply rail;
- a driver stage connected to drive said transistors in phase opposition;
- wherein said pair of transistors comprises a PNP bipolar pull-up transistor and an n-channel power field effect push-down transistor;
- wherein said output node is connected to a loudspeaker;
- wherein said driver stage is an analog differential amplifier.
An integrated circuit power audio output stage, comprising:
- a PNP integrated power bipolar transistor having a base terminal, a collector terminal operatively connected to an output node, and an emitter terminal operatively connected to a first supply rail;
- an N-channel power DMOS transistor having a gate terminal, a drain terminal operatively connected to said output node, and a source terminal operatively connected to a second supply rail which is more negative than said first supply rail;
- said base terminal and said gate terminal being interconnected so that said bipolar transistor and said DMOS transistor are driven in phase opposition;
- wherein said output node drives a loudspeaker.
An integrated circuit power output audio stage, comprising:
- a PNP integrated power bipolar transistor having a base terminal, a collector terminal operatively connected to an output node, and an emitter terminal operatively connected to a first supply rail;
- an N-channel power DMOS transistor having a gate terminal, a drain terminal operatively connected to said output node, and a source terminal operatively connected to a second supply rail which is more negative than said first supply rail;
- an additional field-effect transistor, connected to drive said base terminal of said power bipolar transistor;
- and
- a driver circuit connected to drive said bipolar transistor and said DMOS transistor in phase opposition;
- said bipolar transistor being driven through said additional transistor;
- wherein said output node drives a loudspeaker.
Dependencies are inferred from the claim text.