1. A power-amplifier (PA) comprising:
a PA circuit that includes a bipolar junction transistor (BJT) having a base, a collector and an emitter, the BJT configured to receive a radio-frequency (RF) signal through an input path and amplify the RF signal;
a biasing circuit in communication with the PA circuit, the biasing circuit configured to provide a first bias signal or a second bias signal to the PA circuit for operation in a first mode or a second mode, respectively, each of the first bias signal and the second bias signal routed to the BJT through a path that includes a common node and a ballast; and
a linearizing circuit implemented between the common node and a node along the input path, the linearizing circuit configured to provide a coupling path between the common node and the input path to improve linearity of the PA circuit operating in the first mode while allowing the ballast to be sufficiently robust for the PA circuit operating in the second mode.
2. The PA of claim 1 wherein the ballast includes a DC ballasting resistance.
3. The PA of claim 1 wherein the BJT includes a heterojunction bipolar transistor (HBT).
4. The PA of claim 1 wherein the BJT is configured such that the RF signal is received at the base through the input path, and the amplified RF signal is output through the collector.
5. The PA of claim 4 wherein the first mode includes an EDGE (enhanced data rates for GSM evolution) mode, and the second mode includes a GPRS (general packet radio service) mode.
6. The PA of claim 5 wherein the biasing circuit includes a current mirror that generates the first bias signal for the operation of the PA circuit in the EDGE mode.
7. The PA of claim 6 wherein the current mirror includes a BJT coupled to a reference current source, the first bias signal being output through an emitter of the BJT to be provided to the common node.
8. The PA of claim 7 wherein the ballast is implemented between the common node and the base of the PA BJT, such that the common node functions as a base-emitter junction between the base of the PA BJT and the emitter of the current mirror BJT.
9. The PA of claim 8 wherein the input path includes a DC blocking capacitance implemented between the base of the PA BJT and a node where the linearizing circuit is connected to.
10. The PA of claim 9 wherein the linearizing circuit is configured to couple the RF signal between the input path and the base-emitter junction to provide rectification on the base-emitter junction and correct AM-AM distortion and thereby yield the improved linearity.
11. The PA of claim 5 wherein the biasing circuit includes a bias resistance implemented between a GPRS bias node and the common node, such that the second bias signal is provided to the gate of the BJT from the GPRS bias node through the bias resistance, the common node, and the ballast.
12. The PA of claim 1 wherein the PA circuit includes a second BJT configured to provide another stage of amplification.
13. The PA of claim 12 wherein the second BJT is implemented so that the input path of the BJT is coupled to an output of the second BJT.
14. The PA of claim 12 wherein the second BJT is configured to receive the amplified RF signal from the BJT.
15. The PA of claim 1 wherein the linearizing circuit includes a capacitance.
16. The PA of claim 15 wherein the capacitance includes a capacitor.
17. The PA of claim 15 wherein the linearizing circuit further includes a resistance connected in series with the capacitance.
18. The PA of claim 15 wherein the linearizing circuit further includes an inductance connected in series with the capacitance.
19. A power-amplifier (PA) module comprising:
a packaging substrate configured to receive a plurality of components;
a power amplifier (PA) circuit formed on a die that is mounted on the packaging substrate, the PA circuit including a bipolar junction transistor (BJT) having a base, a collector and an emitter, the BJT configured to receive a radio-frequency (RF) signal through an input path and amplify the RF signal;
a biasing circuit in communication with the PA circuit, the biasing circuit configured to provide a first bias signal or a second bias signal to the PA circuit for operation in a first mode or a second mode, respectively, each of the first bias signal and the second bias signal routed to the BJT through a path that includes a common node and a ballast; and
a linearizing circuit implemented between the common node and a node along the input path, the linearizing circuit configured to provide a coupling path between the common node and the input path to improve linearity of the PA circuit operating in the first mode while allowing the ballast to be sufficiently robust for the PA circuit operating in the second mode.
20. A method for operating a power-amplifier (PA), the method comprising:
receiving a radio-frequency (RF) signal through an input path in a PA circuit that includes a bipolar junction transistor (BJT) having a base, a collector and an emitter;
providing a first bias signal or a second bias signal to the PA circuit for operation in a first mode or a second mode, respectively, each of the first bias signal and the second bias signal routed to the BJT through a path that includes a common node and a ballast; and
coupling the common node and a node along the input path with a linearizing circuit to improve linearity of the PA circuit operating in the first mode while allowing the ballast to be sufficiently robust for the PA circuit operating in the second mode.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What is claimed is:
1. A method for introducing encapsulating material into an ignition coil comprising a primary winding, a secondary winding co-axially disposed relative to the primary winding, and a secondary spool for receiving the secondary winding, the method comprising:
providing a fluid-directing device at a first end of the secondary spool;
providing flow communication between the fluid-directing device and a first channel defined between the outer diameter of the primary winding and the inner diameter of the secondary spool;
providing flow communication between the first channel and a second channel at a distal end from the first end, the second channel defined between the outer diameter of the secondary winding and the housing of the ignition coil;
introducing encapsulating material through the fluid-directing device for generally downwardly flow into the first channel; and
at the distal end, turning the downwardly flow into a generally upwardly flow into the second channel to avoid the trapping of air as the encapsulating material fills the second channel.
2. The method of claim 1 further comprising defining a window in the fluid-directing device for receiving an interface circuit.
3. The method of claim 2 further comprising sealingly mounting the interface circuit through the window.
4. An ignition coil comprising:
a primary winding;
a secondary winding co-axially disposed relative to the primary winding;
a secondary spool for receiving the secondary winding;
a fluid-directing device at a first end of the secondary spool;
a first channel defined between the outer diameter of the primary winding and the inner diameter of the secondary spool, the first channel flowingly connected to the fluid-directing device;
a second channel flowingly connected with the first channel at a distal end from the first end, the second channel defined between the outer diameter of the secondary winding and the housing of the ignition coil, wherein encapsulating material is introduced for downwardly flow through the fluid-directing device into the first channel; and
flow-turning structure configured to turn the downwardly flow of encapsulating material passing from the first channel to an upwardly flow into the second channel so as to avoid the trapping of air as the encapsulating material fills the second channel.
5. The ignition coil of claim 4 further comprising a window in the fluid-directing device for receiving an interface.
6. The ignition coil of claim 5 wherein the window is configured to sealingly receive the interface circuit.
7. The ignition coil of claim 4 wherein the fluid-directing device comprises a funnel.
8. An ignition coil comprising:
a primary winding;
a secondary winding co-axially disposed relative to the primary winding;
a secondary spool for receiving the secondary winding;
a fluid-directing device at a first end of the secondary spool;
a first channel flowingly connected to the fluid-directing device;
a second channel flowingly connected with the first channel at a distal end from the first end; and
flow-turning structure configured to turn downwardly flow of material passing from one of the channels to an upwardly flow into the other channel so as to avoid the trapping of air as the material fills the other channel.
9. The ignition coil of claim 8 wherein the first channel is defined between the outer diameter of the primary winding and the inner diameter of the secondary spool.
10. The ignition coil of claim 9 wherein the second channel is defined between the outer diameter of the secondary winding and the housing of the ignition coil.
11. The ignition coil of claim 10 wherein encapsulating material is introduced for downwardly flow through the fluid-directing device into the first channel.
12. The ignition coil of claim 11 wherein the flow-turning structure turns the downwardly flow of encapsulating material passing from the first channel to an upwardly flow into the second channel.
13. The ignition coil of claim 12 wherein the fluid-directing device comprises a funnel.
14. A method for introducing encapsulating material into an ignition coil comprising a primary winding, a secondary winding co-axially disposed relative to the primary winding, and a secondary spool for receiving the secondary winding, the method comprising:
providing a fluid-directing device at a first end of the secondary spool;
flowingly connecting a first channel to the fluid-directing device;
flowingly connecting a second channel with the first channel at a distal end from the first end; and
turning downwardly flow of material passing from one of the channels to an upwardly flow into the other channel so as to avoid the trapping of air as the material fills the other channel.
15. The method of claim 14 wherein the first channel is defined between the outer diameter of the primary winding and the inner diameter of the secondary spool.
16. The method of claim 15 wherein the second channel is defined between the outer diameter of the secondary winding and the housing of the ignition coil.
17. The method of claim 16 further comprising introducing encapsulating material through the fluid-directing device for downwardly flow into the first channel.
18. The method of claim 17 further comprising turning the downwardly flow of encapsulating material passing from the first channel to an upwardly flow into the second channel.
19. A method for introducing encapsulating material into an ignition coil comprising a primary winding, a secondary winding co-axially disposed relative to the primary winding, and a secondary spool for receiving the secondary winding, the method comprising:
providing a device for directing pressurized fluid at a first end of the secondary spool;
providing flow communication between the fluid-directing device and a first channel defined between the outer diameter of the primary winding and the inner diameter of the secondary spool;
providing flow communication between the first channel and a second channel at a distal end from the first end, the second channel defined between the outer diameter of the secondary winding and the housing of the ignition coil;
introducing pressurized encapsulating material through the fluid-directing device into the first channel; and
at the distal end, turning the flow of encapsulating material passing from the first channel into a generally upwardly flow into the second channel to avoid the trapping of air as the encapsulating material fills the second channel.
20. An ignition coil comprising:
a primary winding;
a secondary winding co-axially disposed relative to the primary winding;
a secondary spool for receiving the secondary winding;
a device for directing pressurized fluid at a first end of the secondary spool;
a first channel defined between the outer diameter of the primary winding and the inner diameter of the secondary spool, the first channel flowingly connected to the fluid-directing device;
a second channel flowingly connected with the first channel at a distal end from the first end, the second channel defined between the outer diameter of the secondary winding and the housing of the ignition coil, wherein pressurized encapsulating material is introduced through the fluid-directing device into the first channel; and
flow-turning structure configured to turn the flow of encapsulating material passing from the first channel to an upwardly flow into the second channel so as to avoid the trapping of air as the encapsulating material fills the second channel.
21. The ignition coil of claim 20 wherein the device directing pressurized fluid comprises a nozzle, and a funnel configured to engagingly receive the nozzle.
22. The ignition coil of claim 21 wherein the nozzle and the funnel are configured to provide a mutually corresponding taper to the surfaces providing engagement therebetween.
23. The ignition coil of claim 21 further comprising a sealing ring for providing a sealing engagement between the nozzle and the funnel.