Methods and apparatus for producing a three-state single wire control
First Claim
1. A signal communications apparatus having an output that is switchable between three states, the signal communications apparatus comprising:
- a three-position input device having a first terminal coupled to a first reference voltage and a second terminal coupled to a second reference voltage, wherein the three-position input device is configured to select a switch output signal from the first reference voltage, the second reference voltage and an intermediate state; and
a voltage divider circuit coupled to the first and second reference voltages and having a common node therebetween, wherein the voltage divider circuit is configured to receive the switch output signal at the common node and to produce a predetermined voltage at the common node when the switch output corresponds to the intermediate state to thereby produce the output of the signal communications apparatus.
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Accused Products
Abstract
Systems, methods and devices are described that provide a three-state control signal across a single electrical conductor. A three-position switch provides an output signal that selects between the first reference voltage, a second reference voltage and an intermediate voltage. The output from the switch is transmitted to a voltage divider circuit that produces a predetermined result when the switch output corresponds to the intermediate state. The output of the voltage divider is then provided to an analog-to-digital converter to decode the state of the switch. The three-state control signal may be used, for example, to place a vehicle component such as a windshield temperature controller or rear-window defogger into a desired one of three operating states. Similarly, the three-state concepts may be widely applied in many automotive, industrial, consumer electronics and other settings.
11 Citations
95 Claims
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1. A signal communications apparatus having an output that is switchable between three states, the signal communications apparatus comprising:
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a three-position input device having a first terminal coupled to a first reference voltage and a second terminal coupled to a second reference voltage, wherein the three-position input device is configured to select a switch output signal from the first reference voltage, the second reference voltage and an intermediate state; and
a voltage divider circuit coupled to the first and second reference voltages and having a common node therebetween, wherein the voltage divider circuit is configured to receive the switch output signal at the common node and to produce a predetermined voltage at the common node when the switch output corresponds to the intermediate state to thereby produce the output of the signal communications apparatus. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A circuit for providing a three-state input to an analog-to-digital converter, the circuit comprising:
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a three-position switch having a first terminal coupled to a first reference voltage and a second terminal coupled to a second reference voltage, wherein the three-position switch is operable to select a switch output signal from the first reference voltage, the second reference voltage and an intermediate state; and
a voltage divider circuit comprising a first resistor and a second resistor coupled to the first and second reference voltages, respectively, and having a common node therebetween corresponding to the input of the analog-to-digital converter, wherein the voltage divider circuit is configured to receive the switch output at the common node and to provide a predetermined voltage at the common node when the switch output corresponds to the intermediate state.
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12. An electrical switching apparatus comprising:
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a switch having three operating states;
a wire coupled to the switch to transmit an analog signal corresponding to one of the three operating states;
a voltage divider coupled to the wire to receive the analog signal; and
an analog-to-digital (A/D) converter coupled to the voltage divider, wherein the A/D converter is configured to determine the operating state of the switch from the analog signal.
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13. A electronic switching system for placing a vehicle component into a desired one of three states, the switching system comprising:
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a three-position input device having a first terminal coupled to a first reference voltage and a second terminal coupled to a second reference voltage, wherein the three-position input device is operable to select a switch output signal from the first reference voltage, the second reference voltage and an intermediate state;
a voltage divider circuit configured to receive the first and second reference voltages and having a common node located therebetween, wherein the voltage divider circuit is configured to receive the switch output at the common node and to provide a voltage divider output corresponding to a predetermined voltage when the switch output corresponds to the intermediate state, and otherwise to provide the voltage divider output corresponding to the switch output; and
an analog-to-digital converter configured to receive and decode the voltage divider output to thereby place the vehicle component into the desired state. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54)
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55. An electrical switching system capable of diagnosing a fault condition relating to a vehicle component, the electrical switching system comprising:
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a switch operable to select a switch output signal from a first state and a second state;
a voltage divider circuit configured to receive the switch output signal and to provide a voltage divider output in response to the switch output signal, wherein the three-state voltage divider output comprises one of three states corresponding to the first and second states of the switch output signal in addition to a diagnosable state, wherein the diagnosable state corresponds to the fault condition; and
an analog-to-digital converter configured to receive and decode the voltage divider output to thereby place the vehicle component into the desired state and to identify the fault condition if the diagnosable state occurs. - View Dependent Claims (56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95)
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Specification