The invention may be best understood by referring to the following description and accompanying drawings that are used to illustrate embodiments of the invention. In the drawings:
A method and apparatus for providing input voltages to power amplifiers is disclosed. For one embodiment of the invention, a device having multiple PAs is provided with a voltage adjustment mechanism that adjusts the output voltage from the voltage regulator (switcher) based upon the PA that is currently in use. For one embodiment, a multiple-mode device has a corresponding PA for each mode. When a mode is selected, the voltage adjustment mechanism adjusts the voltage based upon the corresponding PA. For one embodiment of the invention the voltage adjustment mechanism is controlled by firmware or software of a digital processing system (DPS) of the host device. For one embodiment of the invention, the voltage adjustment mechanism includes a digital potentiometer controlled by the host DPS. Additionally, or alternatively, embodiments of the invention may include a voltage detector/comparator to determine the input voltage of the switcher and adjusts the input voltage if the input voltage is above a specified maximum value. For one embodiment of the invention, the maximum specified value is determined by the input voltage specification of the switcher. For one embodiment of the invention, the input voltage and output voltage are compared and the input voltage adjusted if the output voltage is not sufficiently greater than the input voltage.
In the following description, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practiced without these specific details. In other instances, well-known circuits, structures and techniques have not been shown in detail in order not to obscure the understanding of this description.
Reference throughout the specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearance of the phrases “in one embodiment” or “in an embodiment” in various places throughout the specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.
Moreover, inventive aspects lie in less than all features of a single disclosed embodiment. Thus, the claims following the Detailed Description are hereby expressly incorporated into this Detailed Description, with each claim standing on its own as a separate embodiment of this invention.
Embodiments of the invention are applicable to devices that implement PAs including wireless communications devices implementing multiple PAs having differing operational voltages.
For one embodiment of the invention, a DPS of the device (not shown) executes software or firmware that operates as an operational mode selection mechanism and determines which operational mode has been selected. The DPS controls the feedback network circuit in accordance with the operational mode selected.
It will be readily apparent to those skilled in the art that for devices implementing multiple PAs requiring more than two different input voltage levels, a more complicated feedback network circuit can be implemented to provide three or more voltage levels to different PAs. For one embodiment of the invention, a digital potentiometer is implemented in place of the feedback network to provide several different VPAs as directed by the DPS. For example, a digital potentiometer may be substituted for resistor R2 in order to provide multiple different resistance values within the feedback network and thus provide multiple output voltages.
At operation 210 a voltage corresponding to the selected mode is determined. The determined voltage may be a voltage that is within a specified range of operational voltage for a PA corresponding to the selected mode. For example, if TDMA mode is selected and the PA in use for TDMA mode has a specified operational voltage range of 3.84V-3.86V, then the determined voltage may be 3.85V.
At operation 215 a voltage adjustment mechanism is employed to adjust the output voltage of the switcher to the determined voltage. For one embodiment of the invention, the voltage adjustment mechanism may be a digital potentiometer controlled by software executed by a DPS of the device. For one such embodiment, the potentiometer is automatically adjusted based on the selected operational mode of the device. The potentiometer in turn tunes the switcher power supply to supply a voltage based on and optimized for the particular PA used for the selected operational mode. As discussed above, there are many different ways of implementing a voltage adjustment mechanism to adjust the voltage from the power supply based upon the selected operational mode of the device.
At operation 220 the power supply provides input voltage to the PA based upon the operation of the voltage adjustment mechanism. For one embodiment of then invention, the PA operates more efficiently because the input voltage from the power supply has been adjusted to more closely match the optimal operating voltage of the power supply.
During subsequent operation of the device, if a different mode of operation is selected, the operations of process 200 are repeated to adjust the voltage from the power supply to more closely match the optimal operational voltage of the PA corresponding to the subsequently selected mode of operation.
As discussed above, an embodiment of the invention includes a voltage detector/comparator to determine the input voltage of the switcher and adjusts the input voltage if the input voltage is above a specified maximum value. For one such embodiment of the invention, the specified maximum value is determined by the input voltage specification of the switcher. For one embodiment of the invention, the input voltage and output voltage are compared and the input voltage adjusted if the output voltage is not sufficiently greater than the input voltage.
As shown in
As discussed above in reference to the voltage adjustment mechanism 115, the voltage adjustment mechanism may be implemented in variety of ways which will be apparent to those skilled in the art. R1 could be a power resistor, diode, transistor, or any other device or combination of devices capable of creating the required voltage drop and deliver current to the voltage detector/comparator 321. When Vin exceeds a specified threshold voltage, the output from the voltage detector/comparator 321 turns transistor Q4 off and reduces the input voltage to the booster switch 305. Alternative embodiments of the invention may include a digital potentiometer controlled by software or firmware executed by a DPS of the device. Such an embodiment would allow the input voltage to be dropped by a desired and variable amount based upon the output voltage of the switcher.
Referring to
Main memory 404 may be, e.g., a random access memory (RAM) or some other dynamic storage device, for storing information or instructions (program code), which are used by CPU 402 or signal processor 403. Main memory 404 may store temporary variables or other intermediate information during execution of instructions by CPU 402 or signal processor 403. Static memory 406, may be, e.g., a read only memory (ROM) and/or other static storage devices, for storing information or instructions, which may also be used by CPU 402 or signal processor 403. Mass storage device 407 may be, e.g., a hard disk drive or optical disk drive, for storing information or instructions for processing system 400.
Embodiments of the invention include methods apparatuses for automatically adjusting the voltage from the power supply based a selected operation mode corresponding to one of multiple power supplies. For one embodiment of the invention the voltage adjustment mechanism may be implemented as a variable feedback network. For one such embodiment of the invention, the voltage adjustment mechanism is implemented as a hardwired resistor/transistor circuit in which one or more transistors are opened or closed to create a combination of resistance corresponding to a voltage determined for a selected mode of operation with the selected mode information provide to the circuit by a DPS of the device. For alternative Alternatively, the voltage adjustment mechanism may be implemented as a digital potentiometer or as a power supply with adjustable voltage output. For one embodiment of the invention, the voltage adjustment mechanism is controlled by software or firmware executed by a DPS of the device.
Embodiments of the invention may also include a voltage adjustment mechanism that adjusts the input voltage to the switcher to maintain a specified difference between input voltage and output voltage so that the switcher maintains stable operation. For one embodiment of the invention, a switcher output voltage adjustment mechanism (e.g., voltage adjustment mechanism 115) is implemented to adjust the output voltage of the switcher based upon a selected operational mode and corresponding PA and a switcher input voltage adjustment mechanism (e.g., voltage adjustment mechanism 320) is implemented to adjust the input voltage to provide stable switcher operation (e.g., to adjust the input voltage so that a differential is maintained between switcher input voltage and switcher output voltage).
Or for example, as described above in reference to
Embodiments of the invention have been described as including various operations. Many of the processes are described in their most basic form, but operations can be added to or deleted from any of the processes without departing from the scope of the invention. For example, as described in reference to
The operations of the invention may be performed by hardware components or may be embodied in machine-executable instructions, which may be used to cause a general-purpose or special-purpose processor or logic circuits programmed with the instructions to perform the operations. Alternatively, the steps may be performed by a combination of hardware and software. The invention may be provided as a computer program product that may include a machine-readable medium having stored thereon instructions, which may be used to program a computer (or other electronic devices) to perform a process according to the invention. The machine-readable medium may include, but is not limited to, floppy diskettes, optical disks, CD-ROMs, and magneto-optical disks, ROMs, RAMs, EPROMs, EEPROMs, magnet or optical cards, flash memory, or other type of media/machine-readable medium suitable for storing electronic instructions. Moreover, the invention may also be downloaded as a computer program product, wherein the program may be transferred from a remote computer to a requesting computer by way of data signals embodied in a carrier wave or other propagation medium via a communication cell (e.g., a modem or network connection).
While the invention has been described in terms of several embodiments, those skilled in the art will recognize that the invention is not limited to the embodiments described, but can be practiced with modification and alteration within the spirit and scope of the appended claims. The description is thus to be regarded as illustrative instead of limiting.