Programmable low dropout regulators with fast transient response when programming output voltage
First Claim
1. A power amplifier system comprising:
- a power amplifier configured to provide amplification to a radio frequency signal; and
a programmable low dropout regulator having an output that powers at least one stage of the power amplifier with an output voltage that is programmable to a plurality of different voltage levels, the programmable low dropout regulator including an output capacitor electrically connected to the output, a regulation transistor having a drain electrically connected to the output capacitor and configured to charge the output capacitor in response to programming the output voltage from a low voltage level to a high voltage level, an amplifier configured to control a gate voltage of the regulation transistor, and an alternative discharge circuit configured to activate to discharge the output capacitor in response to programming the output voltage from the high voltage level to the low voltage level.
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Accused Products
Abstract
Apparatus and methods for programmable low dropout (LDO) regulators for radio frequency (RF) electronics are provided herein. In certain configurations, an LDO regulator for generating a programmable output voltage includes a regulation field-effect transistor (FET) having a drain electrically connected to the LDO regulator'"'"'s output, an error amplifier that controls a gate of the regulation FET, a feedback circuit that provides a feedback signal to an inverting input of the error amplifier, an output capacitor electrically connected to the LDO regulator'"'"'s output, and an alternative discharge circuit. When the output voltage of the LDO regulator is programmed from a high voltage level to a low voltage level, the alternative discharge circuit activates to discharge the output capacitor to improve the LDO regulator'"'"'s transient response.
15 Citations
20 Claims
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1. A power amplifier system comprising:
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a power amplifier configured to provide amplification to a radio frequency signal; and a programmable low dropout regulator having an output that powers at least one stage of the power amplifier with an output voltage that is programmable to a plurality of different voltage levels, the programmable low dropout regulator including an output capacitor electrically connected to the output, a regulation transistor having a drain electrically connected to the output capacitor and configured to charge the output capacitor in response to programming the output voltage from a low voltage level to a high voltage level, an amplifier configured to control a gate voltage of the regulation transistor, and an alternative discharge circuit configured to activate to discharge the output capacitor in response to programming the output voltage from the high voltage level to the low voltage level. - View Dependent Claims (2)
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3. A power amplifier system comprising:
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a power amplifier configured to provide amplification to a radio frequency signal; and a programmable low dropout regulator having an output that powers at least one stage of the power amplifier with an output voltage that is programmable to a plurality of different voltage levels, the programmable low dropout regulator including an output capacitor electrically connected to the output, a regulation transistor having a drain electrically connected to the output capacitor, an amplifier configured to control a gate voltage of the regulation transistor, and an alternative discharge circuit configured to activate to discharge the output capacitor in response to programming the output voltage from a high voltage level to a low voltage level, the alternative discharge circuit including a comparator configured to compare the output voltage to a trigger voltage, and to selectively activate an electrical path through the alternative discharge circuit based on the comparison. - View Dependent Claims (4, 5, 6)
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7. A mobile device comprising:
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an antenna; a transceiver electrically connected to the antenna via a transmit path through a power amplifier; and a programmable low dropout regulator having an output that powers at least one stage of the power amplifier with an output voltage that is programmable to a plurality of different voltage levels, the programmable low dropout regulator including an output capacitor electrically connected to the output, a regulation transistor having a drain electrically connected to the output capacitor, an amplifier configured to control a gate voltage of the regulation transistor, and an alternative discharge circuit configured to activate to discharge the output capacitor in response to programming the output voltage from a high voltage level to a low voltage level, the transceiver configured to generate a control signal operable to control a programmed voltage level of the output voltage. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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8. A mobile device comprising:
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an antenna; a transceiver electrically connected to the antenna via a transmit path through a power amplifier; a programmable low dropout regulator having an output that powers at least one stage of the power amplifier including an input stage of the power amplifier with an output voltage that is programmable to a plurality of different voltage levels, the programmable low dropout regulator including an output capacitor electrically connected to the output, a regulation transistor having a drain electrically connected to the output capacitor, an amplifier configured to control a gate voltage of the regulation transistor, and an alternative discharge circuit configured to activate to discharge the output capacitor in response to programming the output voltage from a high voltage level to a low voltage level; and an envelope tracker that powers an output stage of the power amplifier.
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9. A mobile device comprising:
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an antenna; a transceiver electrically connected to the antenna via a transmit path through a power amplifier; a programmable low dropout regulator having an output that powers at least one stage of the power amplifier including an input stage of the power amplifier with an output voltage that is programmable to a plurality of different voltage levels, the programmable low dropout regulator including an output capacitor electrically connected to the output, a regulation transistor having a drain electrically connected to the output capacitor, an amplifier configured to control a gate voltage of the regulation transistor, and an alternative discharge circuit configured to activate to discharge the output capacitor in response to programming the output voltage from a high voltage level to a low voltage level; and a DC-to-DC converter that powers an output stage of the power amplifier.
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16. A packaged module comprising:
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a package substrate; a plurality of surface mount components attached to the package substrate and including an output capacitor; and a semiconductor die attached to the package substrate and comprising a programmable low dropout regulator having an output that powers at least one stage of a power amplifier with an output voltage that is programmable to a plurality of different voltage levels, the programmable low dropout regulator including a regulation transistor having a drain electrically connected to the output capacitor, an amplifier configured to control a gate voltage of the regulation transistor, and an alternative discharge circuit configured to activate to discharge the output capacitor in response to programming the output voltage from a high voltage level to a low voltage level, the alternative discharge circuit further including a discharge control circuit in an electrical path and configured to limit an amount of current that the alternative discharge circuit discharges from the output capacitor. - View Dependent Claims (17, 18, 19, 20)
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Specification