METHODS AND APPARATUSES FOR PERFORMING COMMON MODE PULSE COMPENSATION IN AN OPTO-ISOLATOR
First Claim
1. An opto-isolator comprising:
- a transmitter circuit having an electrical-to-optical converter (EOC) control circuit for controlling an EOC, a primary current source for generating a drive current for driving an EOC, and a common mode pulse compensation (CMPC) circuit that senses if a common mode pulse event is occurring, and if so, generates a compensation current that is output from a first output terminal of the CMPC circuit to the current source such that the compensation current and the drive current add together to produce a new drive current that is used to drive the EOC, and wherein a common mode pulse event corresponds to a common mode pulse waveform occurring between a reference ground, GND1, of the transmitter circuit and a reference ground, GND2, of the receiver circuit;
an electrical-to-optical converter (EOC) operatively connected to the transmitter circuit, wherein the EOC receives the new drive current from the CMPC circuit and produces an optical signal that is based on the new drive current received by the EOC; and
a receiver circuit having an optical-to-electrical converter (OEC), an amplifier, a comparator and an output driver, wherein the OEC receives the optical signal produced by the EOC, converts the optical signal into an electrical signal, and outputs the electrical signal, the amplifier amplifying the electrical signal output from the OEC, the comparator comparing the amplified electrical signal to a reference signal and producing an electrical output signal based on the comparison, the output driver receiving the electrical output signal and producing an electrical output drive signal for the opto-isolator.
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Accused Products
Abstract
In an opto-isolator, a common mode pulse compensation circuit is provided that senses when a common mode pulse event occurs and that adds current to the LED drive current to compensate for a decrease in the LED drive current caused by the occurrence of the event. The common mode pulse compensation circuit is capable of operating effectively over a very wide range of common mode pulse slopes by automatically adjusting the amount of current that is added to the LED drive current based at least in part on the slope of the sensed common mode pulse. In addition, the common mode pulse compensation circuit is capable of being implemented with LEDs that operate at very low drive currents, which allows the power consumption requirements of the opto-isolator to be reduced.
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Citations
14 Claims
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1. An opto-isolator comprising:
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a transmitter circuit having an electrical-to-optical converter (EOC) control circuit for controlling an EOC, a primary current source for generating a drive current for driving an EOC, and a common mode pulse compensation (CMPC) circuit that senses if a common mode pulse event is occurring, and if so, generates a compensation current that is output from a first output terminal of the CMPC circuit to the current source such that the compensation current and the drive current add together to produce a new drive current that is used to drive the EOC, and wherein a common mode pulse event corresponds to a common mode pulse waveform occurring between a reference ground, GND1, of the transmitter circuit and a reference ground, GND2, of the receiver circuit; an electrical-to-optical converter (EOC) operatively connected to the transmitter circuit, wherein the EOC receives the new drive current from the CMPC circuit and produces an optical signal that is based on the new drive current received by the EOC; and a receiver circuit having an optical-to-electrical converter (OEC), an amplifier, a comparator and an output driver, wherein the OEC receives the optical signal produced by the EOC, converts the optical signal into an electrical signal, and outputs the electrical signal, the amplifier amplifying the electrical signal output from the OEC, the comparator comparing the amplified electrical signal to a reference signal and producing an electrical output signal based on the comparison, the output driver receiving the electrical output signal and producing an electrical output drive signal for the opto-isolator. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for performing common mode pulse compensation in an opto-isolator comprising:
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in a common mode pulse compensation (CMPC) circuit of an opto-isolator, if the CMPC circuit senses that a common mode pulse event is occurring, generating a compensation current in the CMPC circuit to be added to an electrical-to-optical converter (EOC) drive current used for driving an EOC of the opto-isolator; outputting the compensation current from an output terminal of the CMPC circuit to a current source of the transmitter circuit of the opto-isolator; adding the compensation current to a drive current produced by the current source to produce a new drive current; and using the new drive current to drive the EOC of the opto-isolator, wherein using the new drive current to drive the EOC of the opto-isolator compensates for perturbations in the drive current produced by the current source that are caused by the occurrence of the sensed common mode pulse event. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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Specification