US3825852A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Control system comprising differential amplifier with dual current comparator having two outputs separated by a deadband
Assignee: Honeywell Inc
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Filing: 1972-10-05
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Granted: 1974-07-23
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Expires: 1992-10-05
Abstract
Abstract A condition responsive circuit, disclosed as an automatic changeover heat-cool solid state thermostat, is adapted to be connected by three terminals to one or the other alternating current load and to a source of alternating current potential. The solid state condition responsive system uses an improved differential amplifier with dual current comparators and has two outputs separated by a deadband. The differential amplifier and the two current comparators control the firing of a silicon controlled rectifier in the first or second outputs when there is a need to energize one or the other load. The AC supply voltage to the condition responsive system amplifier and current comparators is shorted out early in each half cycle by a four layer diode across the input of the condition responsive circuit. This arrangement allows for switching to a relatively high impedance within the condition responsive circuit to virtually eliminate the power dissipation therein except during the initial portion of each applied waveform and thus also insures that switching of the silicon controlled rectifiers and triacs only occurs near the voltage crossover of the alternating current supply.
Inventors
- 👤 B Pinckaers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 17:31
CPC Classifications
H; H03; H03K; H03K17/00; H03K17/13; H03K17/136; G; G05; G05D; G05D23/00; G05D23/19; G05D23/1906; G05D23/20; G05D23/24
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
257 words
An improved dual output differential amplifier and current comparator circuit for selectively providing an electrical output at either of a first or a second output terminal in response to a signal comprising: first solid state current control means having a control electrode, an input electrode and first and second current source electrodes; second solid state current control means having a control electrode, an input electrode and first and second current source electrodes; conductive means including impedance means connecting said input electrodes together and to a first energizing terminal; circuit means for connecting said control electrodes to a control signal such that said first and second current control means are normally conductive; first and second solid state current comparator means each having a plurality of terminals comprising at least a first control input terminal, a second input terminal, and a common terminal, said first comparator means second input terminal being connected to said first current control means first current source electrode, said second comparator means second input terminal being connected to said second current control means first current source electrode and, said common terminals of said first and second current comparator means being connected to A second energizing terminal; and connection means conductively connecting said second current source electrode of said first current control means to said second comparator means first control input terminal, and said second current source electrode of said second current control means to said first comparator means first control input terminal whereby said first and second current comparator means are normally biased to conduction.
Claim 2
Dependent Claim
257 words
An improved dual output differential amplifier and current comparator circuit for selectively providing an electrical output at either of a first or a second output terminal in response to a signal comprising: first solid state current control means having a control electrode, an input electrode and first and second current source electrodes; second solid state current control means having a control electrode, an input electrode and first and second current source electrodes; conductive means including impedance means connecting said input electrodes together and to a first energizing terminal; circuit means for connecting said control electrodes to a control signal such that said first and second current control means are normally conductive; first and second solid state current comparator means each having a plurality of terminals comprising at least a first control input terminal, a second input terminal, and a common terminal, said first comparator means second input terminal being connected to said first current control means first current source electrode, said second comparator means second input terminal being connected to said second current control means first current source electrode and, said common terminals of said first and second current comparator means being connected to A second energizing terminal; and connection means conductively connecting said second current source electrode of said first current control means to said second comparator means first control input terminal, and said second current source electrode of said second current control means to said first comparator means first control input terminal whereby said first and second current comparator means are normally biased to conduction.
Claim 3
Dependent Claim
23 words
The invention of claim 1 in which said solid state current control means and said solid state current comparator means are transistor means.
Claim 4
Dependent Claim
30 words
The invention of claim 1 in which said first solid state current control means is a PNP transistor having two collector electrodes as the first and second current source electrodes.
Claim 5
Dependent Claim
70 words
The invention of claim 1 in which said first and second solid state current control means each is a composite transistor means including a PNP transistor driving a NPN transistor, which NPN transistor has two emitter electrodes as the first and second current source electrodes, the PNP base electrode is the control electrode and the PNP emitter electrode and the NPN collector electrode are connected together as the input electrode.
Claim 6
Dependent Claim
43 words
The invention of claim 1 having a deadband and in which said connection means further comprises deadband bias means providing a further resistive bias current path from said first energizing terminal to the first control input terminal of each of said comparator means.
Claim 7
Dependent Claim
277 words
A condition responsive control circuit adapted to selectively energize first load means or second load means as necessary from an alternating current voltage source, including: three terminals for said control circuit adapted to be connected to said first load means, said second load means and said voltage source to operatively energize said control circuit to in turn selectively energize said load means; dual output differential amplifier and current comparator means comprising, first and second solid state current control means each having a control electrode, an input power electrode and first and second current source electrodes, first and second solid state current comparator means each having a plurality of terminals comprising at least a first control input terminal, a second input terminal, and a common terminal, first output means connected to said first comparator means, second output means connected to said second comparator means, bias providing means for said comparator means including the second current source electrode of said first current control means directly connected to the first control input terminal of said second comparator means, and the second current source electrode of said second current control means being directly connected to the first control input terminal of said first comparator means; circuit means connecting said three terminals to operably energize said differential amplifier and current comparator means; condition responsive voltage divider network means connected to said first and second current control means control electrode; first solid state switch means connected across the first and third terminals; second solid state switch means connected across the second and third terminals; said first and second switch means being connected to and selectively controlled by said first and second output means.
Claim 8
Dependent Claim
277 words
A condition responsive control circuit adapted to selectively energize first load means or second load means as necessary from an alternating current voltage source, including: three terminals for said control circuit adapted to be connected to said first load means, said second load means and said voltage source to operatively energize said control circuit to in turn selectively energize said load means; dual output differential amplifier and current comparator means comprising, first and second solid state current control means each having a control electrode, an input power electrode and first and second current source electrodes, first and second solid state current comparator means each having a plurality of terminals comprising at least a first control input terminal, a second input terminal, and a common terminal, first output means connected to said first comparator means, second output means connected to said second comparator means, bias providing means for said comparator means including the second current source electrode of said first current control means directly connected to the first control input terminal of said second comparator means, and the second current source electrode of said second current control means being directly connected to the first control input terminal of said first comparator means; circuit means connecting said three terminals to operably energize said differential amplifier and current comparator means; condition responsive voltage divider network means connected to said first and second current control means control electrode; first solid state switch means connected across the first and third terminals; second solid state switch means connected across the second and third terminals; said first and second switch means being connected to and selectively controlled by said first and second output means.
Claim 9
Dependent Claim
38 words
The invention of claim 6 in which said first and second solid state current control means are normally biased to condition and in which said first and second solid state current comparator means are normally biased to conduction.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-07-22 | 1978-01-21 | 1978-07-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-07-22 | 1982-01-21 | 1982-07-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-07-22 | 1986-01-21 | 1986-07-23 | $7700.00 | Window Closed / Lapsed |