Audio amplifier
First Claim
1. An audio amplifier circuit of the AB class including differential amplifier stage (16) having an input (17) for receiving and processing an input auido signal to provide a primary audio signal, a circuit transducer output (12), a primary amplification stage for receiving said primary audio signal and amplifying same to provide a transducer signal to said circuit transducer output (12), bipolar power supply connections (24, 26) for supplying electrical current, said AB class amplifier circuit characterized by said primary amplification stage including at least two MOS-FETS (metal oxide semiconductor-field-effect transistors) (32, 40) in common source connection between said power supply connections and said circuit transducer output (12) and a level-shifting driver stage (48, 50) for driving each MOS-FET.
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Accused Products
Abstract
An amplifier circuit for a speaker 12. The circuit includes an operational amplifier 16 connected to a supply rail 24 and a supply rail 26 through a regulator 28 and a regulator 30. The circuit is characterized by a P channel MOS-FET 32 having a source 34 connected to the rail 24 and a drain 36 connected to the speaker 12 and a gate 38, and an N channel MOS-FET 40 having a source 42 connected to the rail 26 and a drain 44 connected to the speaker 12 and a gate 46. A NPN stage 48 is responsive to the output 56 of the amplifier 16 for establishing a voltage differential between the gate 38 of the MOS-FET 32 and the rail 24 to drive the MOS-FET 32 into conduction. A PNP stage 50 is responsive to the output 56 of the amplifier 16 for establishing a voltage differential between the gate 46 of the MOS-FET 40 and the rail 26 to drive the MOS-FET 40 into conduction. The stages 48, 50 are connected to ground 52. A feedback circuit 94 interconnects the drain 36 of the MOS-FET 32 and the ground 52 side of the stage 48, and a feedback circuit 96 interconnects the drain 44 of the MOS-FET 40 and the ground 52 side of the stage 50. A feedback circuit 98 interconnects the speaker 12 and the amplifier 16 for returning a portion of the output voltage to the amplifier 16 to cause the output signal to track the signal at the input to the amplifier 16. A PNP transistor 68 has its base 72 connected to the source 34 of the MOS-FET 32 and its emitter 70 connected to the rail 24 and its collector 76 connected to the output 12, and an NPN transistor 82 has its base 84 connected to the source 42 of the MOS-FET 40 and its emitter 87 connected to the rail 24 and its collector 90 connected to the output 12.
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Citations
27 Claims
- 1. An audio amplifier circuit of the AB class including differential amplifier stage (16) having an input (17) for receiving and processing an input auido signal to provide a primary audio signal, a circuit transducer output (12), a primary amplification stage for receiving said primary audio signal and amplifying same to provide a transducer signal to said circuit transducer output (12), bipolar power supply connections (24, 26) for supplying electrical current, said AB class amplifier circuit characterized by said primary amplification stage including at least two MOS-FETS (metal oxide semiconductor-field-effect transistors) (32, 40) in common source connection between said power supply connections and said circuit transducer output (12) and a level-shifting driver stage (48, 50) for driving each MOS-FET.
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10. An amplifier circuit of the AB class comprising:
- a transducer output (12), a conventional operational amplifier (16) having an audio signal input (17), a power connection including a positive supply rail (24) and a negative supply rail (26), a positive voltage regulator (28) interconnecting said positive rail (24) and said operational amplifier (16) for providing positive voltage to said operational amplifier (16), a negative voltage regulator (30) interconnecting said negative rail (26) and said operational amplifier (16) for providing negative voltage to said operational amplifier (16), a P channel MOS-FET (32) having a source (34) connected to said positive rail (24) and a drain (36) connected to said transducer output (12) and a gate (38), an N channel MOS-FET (40) having a source (42) connected to said negative rail (26) and a drain (44) connected to said transducer output (12) and a gate (46), an NPN voltage level-shifting and driver stage (48) responsive to the output (56) of said operational amplifier (16) for establishing a voltage differential between said gate (38) of said P channel MOS-FET (32) and said positive rail (24) to drive said P channel MOS-FET (32) into conduction and isolated from being in driving relationship with said N channel MOS-FET, a PNP voltage level-shifting and driver stage (50) responsive to the output (56) of said operational amplifier (16) for establishing a voltage differential between said gate (46) of said N channel MOS-FET (40) and said negative rail (26) to drive said N channel MOS-FET (40) into conduction and isolated from being in driving relationship with said P channel MOS-FET, said driver stages (48,
50) having ground leads being connected to ground (52). - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
- a transducer output (12), a conventional operational amplifier (16) having an audio signal input (17), a power connection including a positive supply rail (24) and a negative supply rail (26), a positive voltage regulator (28) interconnecting said positive rail (24) and said operational amplifier (16) for providing positive voltage to said operational amplifier (16), a negative voltage regulator (30) interconnecting said negative rail (26) and said operational amplifier (16) for providing negative voltage to said operational amplifier (16), a P channel MOS-FET (32) having a source (34) connected to said positive rail (24) and a drain (36) connected to said transducer output (12) and a gate (38), an N channel MOS-FET (40) having a source (42) connected to said negative rail (26) and a drain (44) connected to said transducer output (12) and a gate (46), an NPN voltage level-shifting and driver stage (48) responsive to the output (56) of said operational amplifier (16) for establishing a voltage differential between said gate (38) of said P channel MOS-FET (32) and said positive rail (24) to drive said P channel MOS-FET (32) into conduction and isolated from being in driving relationship with said N channel MOS-FET, a PNP voltage level-shifting and driver stage (50) responsive to the output (56) of said operational amplifier (16) for establishing a voltage differential between said gate (46) of said N channel MOS-FET (40) and said negative rail (26) to drive said N channel MOS-FET (40) into conduction and isolated from being in driving relationship with said P channel MOS-FET, said driver stages (48,
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25. An amplifier circuit comprising:
- a circuit of the AB class, transducer output (12), an operational amplifier (16) having an audio signal input (17) and output referenced to ground, a power connection including a positive voltage supply rail (24) and a negative voltage supply rail (26), a positive voltage regulator (28) interconnecting said positive rail (24) and said operational amplifier (16) for providing positive voltage to said operational amplifier (16), a negative voltage regulator (30) interconnecting said negative rail (26) and said operational amplifier (16) for providing positive voltage to said operational amplifier (16), a P channel MOS-FET (32) having a source (34) connected to said positive rail (24) and a drain (36) connected to said circuit transducer output (12) and a gate (38), an N channel MOS-FET (40) having a source (42) connected to said negative rail (26) and a drain (44) connected to said circuit transducer output (12) and a gate (46), a driver NPN bipolar transistor (120) having a base (122) coupled to the output of said operational amplifier (16) and a collector (124) coupled to said gate (38) of said P channel MOS-FET (32) to said positive voltage rail (24) and an emitter (36) connected to ground (52) for shifting the ground referenced voltage to establish a voltage differential between said gate (38) of said P channel MOS-FET (32) and said positive voltage rail (24) to drive said P channel MOS-FET (32) into conduction and isolated from being in driving relationship with said N channel MOS-FET, a driver PNP bipolar transistor (134) having a base (136) coupled to the output of said operational amplifier (16) and a collector (138) coupled to said gate (46) of said N channel MOS-FET (40) to said negative voltage rail (26) and an emitter (144) connected to ground (52) for shifting the ground referenced voltage to establish a voltage differential between said gate (46) of said N channel MOS-FET (40) and said negative voltage rail (26) to drive said N channel MOS-FET (40) into conduction and isolated from being in driving relationship with said P channel MOS-FET.
- View Dependent Claims (26, 27)
Specification