Patent US4546262A successfully refreshed from Google Patents.
US4546262A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Isolated high voltage controller
Assignee: Xerox Corp
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Filing: 1983-06-27
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Granted: 1985-10-08
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Expires: 2003-06-27
Abstract
Abstract The use of pulse width modulation rather than analog excitation to control the resistance of a light emitting diode--photoresistor pair is described. In particular, for two LED/LDR opto-isolators in a totem pole configuration, the duty cycle of the first opto-isolator is arranged to equal 1 minus the duty cycle of the second opto-isolator. Thus, both opto-isolators are always active resulting in the ratiometric output being proportional to the duty cycle, and the output impedance being constant.
Inventors
- 👤 Raymond W. Huggins
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-10 01:06
CPC Classifications
G; G01; G01R; G01R15/00; G01R15/14; G01R15/22
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
143 words
A high voltage controller comprising a first and a second light source, a buffer connected to the first light source, an inverting buffer connected to the second light source, a pulse width modulator, the output of the pulse width modulator connected to the buffer and inverting buffer, a first light dependent resistor optically coupled to the first light source, a second light dependent resistor optically coupled to the second light source, the light dependent resistors having a common connection, a load circuit connected to the common connection of the light dependent resistors, a differential amplifier providing an input circuit to the pulse width modulator, and a feedback circuit interconnecting the common connection of the light dependent resistors, each of the light dependent resistors connected to a high voltage source, and the differential amplifier whereby a constant output impedance high voltage controller is provided.
Claim 2
Dependent Claim
143 words
A high voltage controller comprising a first and a second light source, a buffer connected to the first light source, an inverting buffer connected to the second light source, a pulse width modulator, the output of the pulse width modulator connected to the buffer and inverting buffer, a first light dependent resistor optically coupled to the first light source, a second light dependent resistor optically coupled to the second light source, the light dependent resistors having a common connection, a load circuit connected to the common connection of the light dependent resistors, a differential amplifier providing an input circuit to the pulse width modulator, and a feedback circuit interconnecting the common connection of the light dependent resistors, each of the light dependent resistors connected to a high voltage source, and the differential amplifier whereby a constant output impedance high voltage controller is provided.
Claim 3
Dependent Claim
42 words
The high voltage controller of claim 1 wherein each of the light sources is a light emitting diode having a duty cycle of the first light emitting diode is arranged to equal 1 minus the duty of the second light emitting diode.
Claim 4
Dependent Claim
104 words
A high voltage controller comprising a first opto-isolator, the input to the first opto-isolator being connected to a buffer, a second opto-isolator, the input to the second opto-isolator being connected to an inverting buffer, the outputs of the first opto-isolator and the second opto-isolator being connected in common, a load circuit, the common connection of the opto-isolators providing an output voltage to the load circuit, and a pulse width modulator providing an output signal to the buffer and the inverting buffer, the pulse width modulator being connected to the outputs of the opto-isolators to provide a relative constant output impedance at the load circuit.
Claim 5
Dependent Claim
104 words
A high voltage controller comprising a first opto-isolator, the input to the first opto-isolator being connected to a buffer, a second opto-isolator, the input to the second opto-isolator being connected to an inverting buffer, the outputs of the first opto-isolator and the second opto-isolator being connected in common, a load circuit, the common connection of the opto-isolators providing an output voltage to the load circuit, and a pulse width modulator providing an output signal to the buffer and the inverting buffer, the pulse width modulator being connected to the outputs of the opto-isolators to provide a relative constant output impedance at the load circuit.
Claim 6
Dependent Claim
22 words
The high voltage controller of claim 3 wherein each of the opto-isolators is a light emitting diode and light dependent resistor pair.
Claim 7
Dependent Claim
34 words
The high voltage controller of claim 4 including a differential amplifier providing an input to the pulse width modulator, and a feedback circuit interconnecting the common connection of the opto-isolators and the differential amplifier.
Claim 8
Dependent Claim
38 words
The high voltage controller of claim 4 wherein the duty cycle of the first light emitting diode-light dependent resistor pair is arranged to equal 1 minus the duty cycle of the second light emitting diode-light dependent resistor pair.
Claim 9
Dependent Claim
137 words
A high voltage controller comprising a first opto-isolator pair having a light emitting diode and a light dependent resistor, a second opto-isolator having a light emitting diode and a light dependent resistor, each of the light dependent resistors connected to a high voltage supply, and the common connection of the light dependent resistors providing an output voltage to a load, an input buffer connected to the first opto-isolator, an inverting buffer connected to the second opto-isolator, a pulse width modulator, the output of the pulse width modulator connected to the buffer and inverting buffer, a differential amplifier providing an output signal to the pulse width modulator, and a feedback circuit having a voltage divider network connected to the output voltage and a reference voltage, the voltage divider tap being connected to one input of the differential amplifier.
Claim 10
Dependent Claim
137 words
A high voltage controller comprising a first opto-isolator pair having a light emitting diode and a light dependent resistor, a second opto-isolator having a light emitting diode and a light dependent resistor, each of the light dependent resistors connected to a high voltage supply, and the common connection of the light dependent resistors providing an output voltage to a load, an input buffer connected to the first opto-isolator, an inverting buffer connected to the second opto-isolator, a pulse width modulator, the output of the pulse width modulator connected to the buffer and inverting buffer, a differential amplifier providing an output signal to the pulse width modulator, and a feedback circuit having a voltage divider network connected to the output voltage and a reference voltage, the voltage divider tap being connected to one input of the differential amplifier.
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) | 1988-10-07 | 1989-04-08 | 1989-10-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-10-07 | 1993-04-08 | 1993-10-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-10-07 | 1997-04-08 | 1997-10-08 | $7700.00 | Window Closed / Lapsed |