Amplifier using a single polarity power supply and including depletion mode FET and negative voltage generator
First Claim
1. An amplifier operating with a single polarity power supply, comprising:
- an amplifying stage including at least one depletion-mode FET for amplifying an input ac signal, said FET having a gate coupled to receive said input ac signal, a source connected to ground and a drain coupled to receive a positive voltage; and
a negative voltage generator for providing a negative voltage to bias the gate of said FET,said negative voltage generator comprising a multivibrator generating first and second clock signals, a charge pump receiving said clock signals and operating to produce said negative voltage, and means for providing said negative voltage as a low potential reference to said multivibrator such that said clock signals include a negative potential period and as a result, said charge pump operating in a power efficient manner.
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Abstract
The present invention provides a power amplifier operating with a single power supply. The amplifier includes at least one depletion-mode FET for amplifying an ac signal and a negative voltage generator for providing a bias to the FET. Preferably the amplifier further includes a negative voltage regulator to provide a regulated bias to bias the FET for a class A, AB or B operation. The negative generator includes a multivibrator for producing two clock signals and a charge pump which receives the clock signals and produces a negative voltage. Advantageously the negative voltage is provided as a low reference potential to the multivibrator so that the clock signals it produced include a negative voltage period, which enables the charge pump to operate in a power efficient manner.
149 Citations
30 Claims
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1. An amplifier operating with a single polarity power supply, comprising:
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an amplifying stage including at least one depletion-mode FET for amplifying an input ac signal, said FET having a gate coupled to receive said input ac signal, a source connected to ground and a drain coupled to receive a positive voltage; and a negative voltage generator for providing a negative voltage to bias the gate of said FET, said negative voltage generator comprising a multivibrator generating first and second clock signals, a charge pump receiving said clock signals and operating to produce said negative voltage, and means for providing said negative voltage as a low potential reference to said multivibrator such that said clock signals include a negative potential period and as a result, said charge pump operating in a power efficient manner. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A negative voltage generator operating with a single power supply comprising:
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a multivibrator generating first and second clock signals; a charge pump receiving said first and second clock signals and operating to generate a negative voltage; and means for providing said negative voltage as a low reference potential to said multivibrator such that said clock signals generated by said multivibrator includes a negative potential period and as a result, said charge pump operating in a power efficient manner. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30)
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Specification