1. A deployment system for treating a bifurcation of a main vessel and first and second branch vessels, comprising:
an elongate, flexible body, having a proximal end and a distal end;
a single stent carried by the distal end of the body, the single stent comprising a proximal, upstream end, and a distal, downstream end, and a stent wall extending therebetween;
a releasable restraint, for retaining the stent on the flexible body, the releasable restraint comprising an axially moveable outer sheath having a lubricious layer, wherein a distal end of the lubricious layer is spaced proximally from the outer sheath’s distal end, thereby providing a section of the releasable restraint at the outer sheath’s distal end region that is free of the lubricious layer; and
a distal tip comprising an annular recess formed therein configured to receive the releasable restraint’s distal end, wherein the annular recess at least partially overlaps the lubricious layer;
wherein the distal, downstream end of the stent is larger in diameter than the proximal, upstream end of the stent in an unconstrained expanded configuration, and wherein the stent wall defines a single central lumen and is radially symmetrically disposed about the longitudinal axis of the flexible body when retained on the body.
2. A deployment system as in claim 1, further comprising a guidewire lumen extending axially through at least a portion of the flexible body.
3. A deployment system as in claim 2, wherein the guidewire lumen has a proximal access port and a distal access port, and the proximal access port is positioned along the flexible body, spaced distally apart from the proximal end.
4. A deployment system as in claim 2, wherein the guidewire lumen has a proximal access port and a distal access port, and the proximal access port is positioned at the proximal end of the flexible body.
5. A deployment system as in claim 1, wherein the releasable restraint comprises an axially movable control element extending along a length of the flexible body.
6. A deployment system as in claim 1, wherein the releasable restraint further comprises a pull wire.
7. A deployment system as in claim 1, wherein the releasable restraint further comprises a dissolvable media.
8. A deployment system as in claim 1, wherein the expanded diameter of the single stent tapers radially outwardly in the distal direction.
9. A deployment system as in claim 1, wherein the stent wall is configured to contact and support a wall of the bifurcation from the proximal, upstream end to the distal, downstream end when the stent is deployed in the bifurcation.
10. A deployment system as in claim 1, wherein the stent is uncovered.
11. A deployment system as in claim 1, wherein the lubricious layer is spaced a distance within the range of from about 1 mm to about 3 mm from the outer sheath’s distal end.
12. A deployment system as in claim 1, wherein the releasable restraint comprises a plurality of expansion limiting bands.
13. A deployment system as in claim 1, wherein the stent comprises a drug capable of being eluted over time.
14. A stent deployment catheter, comprising:
an elongate, flexible tubular body, having a proximal end and a distal end;
a noncylindrical, self-expandable stent carried by the distal end, the stent comprising a proximal end, a distal end, and a stent wall extending therebetween, the stent distal end having a larger diameter than the stent proximal end in an unconstrained expanded configuration, wherein the stent is positioned on the distal end of the tubular body such that the stent distal end is located distally relative to the stent proximal end;
a releasable restraint comprising an axially moveable sheath, covering the noncylindrical, self-expandable stent, wherein a distal portion of the sheath comprises a lubricious layer spaced proximally from a distal end of the sheath;
a distal tip comprising an annular recess formed therein configured to receive the distal end of the sheath, wherein the annular recess at least partially overlaps the lubricious layer; and
a handpiece on the proximal end, wherein the handpiece comprises a control and first and second indicia that indicate partial and complete uncovering of the stent with the sheath when the control is aligned with said first and second indicia, respectively, and wherein the control is configured to be moved from an initial position in which the stent is covered to said first and second indicia.
15. A stent deployment catheter as in claim 14, further comprising a guidewire lumen, in an over the wire configuration.
16. A stent deployment catheter as in claim 14, further comprising a guidewire lumen, in a rapid exchange configuration.
17. A stent deployment catheter as in claim 14, wherein the indicia comprises a marking on the handpiece.
18. A stent deployment catheter as in claim 14, wherein the indicia provides tactile feedback to indicate when said control is aligned with said indicia.
19. A deployment system as in claim 14, wherein the stent comprises a drug capable of being eluted over time.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A class AB amplifier configured for true ground operation for a system having a DC-coupled speaker, the amplifier comprising:
an input;
a primary output stage having associated therewith a first feedback loop to the input; and
a secondary stage having associated therewith a second feedback loop to the input, wherein the secondary stage is configured to be at least one of connectable gradually to the DC-coupled speaker upon switch-on of the system and disconnected gradually from the DC-coupled speaker upon switch-off of the system, and the primary output stage is respectively configured to be at least one of connected after the gradual connection of the secondary stage and disconnected before the gradual disconnection of the secondary stage.
2. The class AB amplifier according to claim 1, wherein the secondary stage is connectable to the DC-coupled speaker by a switch.
3. The class AB amplifier according to claim 2, wherein the switch is arranged to be operable with pulse width modulation with a variable mark-space ratio whereby the secondary stage is connectable gradually upon switch-on to the DC-coupled speaker.
4. The class AB amplifier according to claim 1, wherein the input is connectable to either the first feedback loop or the second feedback loop by a feedback switch.
5. The class AB amplifier according to claim 1, wherein the second feedback loop comprises a DC-offset cancelling unit.
6. The class AB amplifier according to claim 5, wherein the DC-offset cancelling unit comprises a series arrangement of a comparator, an integrator, and an amplifier.
7. A method of controlling a class AB amplifier configured for true ground operation during switch-on, the amplifier having an input, a primary output stage having a first feedback loop switchably connectable to the input, and a secondary stage having a second feedback loop separately switchably connectable to the input, the method comprising:
connecting the second feedback loop to the input, gradually connecting the secondary stage to a DC-coupled speaker;
and thereafter connecting the primary stage to the DC-coupled speaker;
disconnecting the second feedback loop; and
connecting the first feedback loop to the input.
8. The method of claim 7, wherein gradually connecting the secondary stage to the speaker comprises:
applying a pulse wave modulation signal to the secondary stage; and
varying on-time of the pulse wave modulation signal from substantially 0% to substantially 100%.
9. A method of controlling a class AB amplifier configured for true ground operation during switch-off, the amplifier having an input, a primary output stage having a first feedback loop switchably connectable to the input, and a secondary stage having a second feedback loop separately switchably connectable to the input, the method comprising:
disconnecting, with a machine the primary stage to the DC-coupled speaker;
disconnecting the first feedback-loop and connecting the second feedback loop to the input; and
gradually disconnecting the secondary stage to the DC-coupled speaker.
10. The method of claim 9, wherein gradually disconnecting the secondary stage to the speaker comprises:
applying a pulse wave modulation signal to the secondary stage; and
varying on-time of the pulse wave modulation signal from substantially 100% to substantially 0%.
11. The method of claim 7, further comprising:
using the second feedback loop to cancel DC-offset while the second feedback loop is connected to the input.
12. The method of claim 9, wherein a feedback signal in the second feedback loop is compared to ground, integrated, and amplified.
13. The class AB amplifier of claim 1, wherein the DC-coupled speaker is coupled between an output of the primary output stage and ground.
14. The class AB amplifier of claim 1, further comprising:
a positive supply; and
a negative supply, wherein the class AB amplifier is symmetrical about ground.