LED bypass and control circuit for fault tolerant LED systems
First Claim
1. A register circuit, comprising:
- a first set of addressable registers comprising a first subset, the first subset of registers comprising On registers of a light emitting diode (LED) light system and a second subset of registers, the second subset of registers comprising Off registers of the light emitting diode (LED) light system;
a logic circuit arranged to select only the first subset in response to a first sequence of K address signals, where K is a positive integer; and
the logic circuit arranged to select a first part of the first subset and a first part of the second subset in response to a second sequence of K address signals.
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Abstract
A light system (FIG. 2) is disclosed. The light system includes a plurality of series connected light emitting diodes (240-246). Each of a plurality of switching devices (230-236) has a control terminal and each has a current path coupled in parallel with a respective LED. A plurality of fault detector circuits (220-226) are each coupled in parallel with a respective light emitting diode. Each fault detector circuit has a first comparator (FIG. 7, 704) arranged to compare a voltage across the respective light emitting diode to a respective first reference voltage (708). When a fault is detected, a control signal is applied to the control terminal to turn on a respective switching device of the plurality of switching devices.
18 Citations
13 Claims
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1. A register circuit, comprising:
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a first set of addressable registers comprising a first subset, the first subset of registers comprising On registers of a light emitting diode (LED) light system and a second subset of registers, the second subset of registers comprising Off registers of the light emitting diode (LED) light system; a logic circuit arranged to select only the first subset in response to a first sequence of K address signals, where K is a positive integer; and the logic circuit arranged to select a first part of the first subset and a first part of the second subset in response to a second sequence of K address signals. - View Dependent Claims (2, 3, 4, 5)
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6. A method of operating a light emitting diode (LED) light system, comprising:
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writing data in a first set of registers, each register of the first set arranged to operate a respective LED of a first plurality of series connected LEDs; writing data in a second set of registers, each register of the second set arranged to operate the respective LED of the first plurality of series connected LEDs; incrementing a count in a first counter in response to a clock signal; turning on each respective LED when a register of the first set matches a respective count of the first counter; and turning off each respective LED when a register of the second set matches a respective count of the first counter. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13)
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Specification