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US 4,063,121 AGranted
Input converter
AssigneeAutomation Systems, Inc.
InventorPeter G. Bartlett
Life of this patent
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Abstract
An input converter circuit for producing a logic level indication of the on or off condition of an input. The input may be AC or DC at any reasonable level. A bilateral photocoupler output is applied to an operational amplifier integrator, which establishes the integration time of the signal. The amplifier output is coupled to a Schmitt trigger having threshold levels at about one third and two thirds of the power supply voltage. The output of the Schmitt trigger provides a logic one output if there is an input signal present and a logic zero output otherwise.
Claims12
An input signal converter comprising:
- 1. an input coupled from an input signal source;
- 2. light emitting means coupled to said input for producing light in response to input signals;
- 3. a light sensitive semiconductor device positioned adjacent said light emitting means;
- 4. an amplifier having a low voltage, current sensitive, low impendance input connected in shunt across said light sensitive device;
- and
- 5. a constant current source supplying current to the shunted pair of said light sensitive device and said amplifier input.
3 more elements
Dependencies are inferred from the claim text.