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US 6,147,558 AGranted
Attenuating volume control
AssigneeESS Technology, Inc.
InventorTerry L. Sculley
Life of this patent
Estimating the term…
Abstract
Two banks of differently-connected resistors are connected as an input to an op-amp feedback circuit.
Claims12
An operational amplifier volume control, comprising:
- an operational amplifier device, having a first input, a second input, and an output;
- a circuit input node;
- an input resistance element, connected between said circuit input node and said first input of said operational amplifier device;
- and
- a feedback connection, connected between said first input of said operational amplifier device and said output of said operational amplifier device,
- said input resistance element including a plurality of resistors and a plurality of switches, including a first set of resistors selectively connected by a first set of switches to a bias level when said switches are actuated, and leaving said resistors and remaining electrically floating when said switches are not connected, and a second set of resistors and second set of switches, connected in series between said first input and said input node, each said switch leaving a resistance in series when unactuated, and removing said resistance when actuated by forming an electrical short circuit across the corresponding resistor,
- wherein said second set of switches comprises a tapped variable resistor and said second input of said operational amplifier is connected to said bias level.
4 more elements
An amplifier circuit, comprising:
- an input node;
- an amplifier element;
- a first resistor set, connected to said input node, said first resistor set comprising a plurality of resistors, each electrically connected to said input node, and a plurality of switches, each electrically connected to each of said resistors, and when actuated, connecting each resistor to a bias voltage, said bias voltage also forming a bias for said amplifier element;
- and
- a second set of resistors, also electrically connected to said input node, and including a resistance element whose resistance can be selectively varied, a combination of resistance from said first set of resistors and said second set of resistors forming an input to said feedback circuit and another electrical element, connecting an output of said feedback circuit to an input of said feedback circuit, wherein said second set of resistors includes a tapped adjustable resistor.
2 more elements
An amplifier circuit, comprising:
- an operational amplifier device, having an inverting first input, a non-inverting second input, and an output;
- a circuit input node to receive an input signal to be amplified by said amplifier device;
- an internal circuit node;
- a first bias node to receive a first bias voltage;
- an input resistor network having a plurality of input resistors, connected between said circuit input node and said internal circuit node;
- a first switch network of one or more switches, connected between said input resistor network and said first bias node, to connect or disconnect one or more input resistors to or from said first bias node in response to a first set of digital control signals;
- a second resistor network having a plurality of resistors, connected between said internal circuit node and said output of said operational amplifier device, wherein, regardless of switching states of said first switch network, each switch of said first switch network is not operable to directly connect to said internal circuit node;
- a second switch network having one or more switches, connected between said second resistor network and said inverting first input, to connect or disconnect one or more resistors in said second resistor network to or from said inverting first input in response to a second set of digital control signals, wherein, regardless of switching states of said first and said second switch networks, said internal circuit node is electrically coupled to each switch in said second switch network through at least one resistor in said second resistor network and each switch of said first switch network is not operable to directly connect to said inverting first input of said operational amplifier device;
- and
- a second bias node connected to said non-inverting second input of said operational amplifier device to receive a second bias voltage.
7 more elements
Dependencies are inferred from the claim text.