70 results about "Lead failure" patented technology

The invention comprises use of Dynamically Switchable Bypass (DSB) elements in association with one or more Light Emitting Diodes (LEDs) in arrays for illumination circuits to provide rugged, reliable lighting. The DSBs are selected from Transient Voltage Suppressors, including Silicon, Metal Oxide Varistors, and Multi Layer Varistors as well as Zener Diodes. The DSBs are not used as circuit protecting devices, but rather as alternative paths for electric current to bypass failed LEDs. Bi-directional TVSs are used as alternative electric paths for circuits using Alternating Current (AC) and parallel LED arrays that light on both phases of AC. Zener Diodes are used in parallel to, but in the opposite polarity orientation to, one or more LEDs in DC or rectified AC circuits. The inventive paired DSB/LED elements overcomes the black-out problems of prior series LED illumination systems, making possible the use of robust LEDs in illumination systems where reliability, long life, low power consumption, low heat output, resistance to shock, vibration, and humidity, and self-diagnosis are important. The DSB elements have breakdown voltages slightly higher than the LED(s) they support, so that when an LED fails, the conduction through the DSB begins. Because the conduction voltage of the DSB so nearly matches the conduction voltage of the LED(s), the remainder of the circuit continues to function as normal. The system is self-diagnostic in that any LED failure presents itself as a dark LED rather than as a whole string of dark LEDs. DSBs may be used with incandescent bulbs.

An embodiment of an LED warning light includes a plurality of LED banks, each including a series of light emitting diodes. LED failure in one or more banks can result in a warning light that appears to be functional, but may not meet relevant standards for light production. The LED warning light monitors current flow through each LED bank to detect failure of an LED and produce a failure signal. The LED warning light includes a microcontroller programmed to evaluate the failure signals and take one or more pre-determined failure mode actions. Failure detection and failure mode actions are defined by program steps taken by firmware running in the microcontroller.

The system consists of an LED failure detection circuit to provide protection against individual LED catastrophic failure. When LED clusters are arranged in a series-parallel configuration, it is important to detect individual LED failure in order to avoid uncontrolled luminous intensity reduction and/or light uniformity degradation. The circuit compares the voltage levels on LEDs with similar position but situated in different chains. In normal conditions, the voltage levels are substantially similar to one another. In case of individual or multiple LED failure, open or shortcircuit, the circuit sends a signal to the automatic turn off circuit that initiates the lamp forced turn off sequence.

A headlamp LED lighting apparatus, which lights an LED block 2 having a plurality of LEDs connected in series, samples the output voltage of the headlamp LED lighting apparatus, calculates the average voltage during every prescribed interval, and has a storage unit for storing the average voltage during every prescribed interval calculated. A control circuit 8 compares the voltage variation in the average voltage during every prescribed interval read out of the storage unit with a prescribed threshold, and decides an LED failure of the LED block 2 from a result of the comparison.

The invention belongs to the technical field of light source illuminating and electronics, in particular relates to an intelligent general light-emitting diode (LED) street lamp illuminating power supply system. The system comprises an input surge protection and electromagnetic interference suppressing circuit, a BOOST-BUCK isolation backlash power factor correction switch power circuit, an LED chip temperature detection circuit, an ambient brightness detection circuit, a permanent calendar chip, a peripheral circuit, an LED failure detection circuit, a singlechip circuit and a constant-current output control circuit. In the switch power circuit of the invention, a circuit structure is simplified and circuit efficiency is improved based on an active power factor correction (PFC) control chip L6562,; and the singlechip circuit monitors the ambient brightness, the temperature of the LED chip, time and LED fault in real time by taking a chip STC12C5606AD as a control core and intelligently adjusts the output brightness of the LED according to different situations, so that energy is saved and the service life of an LED street lamp is prolonged effectively at the same time.

An implanted cardioverter defibrillator (ICD) delivers an electrical therapy signal to the heart of a patient. When ventricular fibrillation or another condition of the heart requiring high voltage therapy is sensed, the therapy signal is delivered to the heart. When a partial short-circuit or other low impedance condition occurs, an over-current protection circuit will stop delivery of a shocking pulse. The ICD will then reduce the voltage of the shocking pulse and try again to deliver electrical therapy. This process is repeated until a voltage level is found that is able to deliver the electrical therapy without causing an over-voltage condition. Alternate lead configurations may also be tried in an attempt to find a signal path that is not affected by the low impedance or short-circuit condition.

A method for automatic threshold control and detection of lead failure in an implanted medical device obtains three sensing vectors for measurement of an electrocardiogram signal. A dynamic error signal is determined from the vectors, and may be used to set a detection threshold for insufficient ECG signals, and/or to passively monitor the device for indications of lead failure without performing an impedance measurement. Passive mode operation conserves battery power and enables continuous lead integrity checks. A quality factor may also be determined from the error signal, to indicate whether or not signal measurements are valid with respect to noise levels. If the detection threshold is allowed to decay between successive features of the electrocardiogram, the decay rate may be made adaptive such that it automatically adjusts to changes in heart rate or to changes in amplitude of the electrocardiogram features.

The invention relates to an overvoltage protection device and method for the alternating current side of a voltage source converter high voltage direct current transmission system. The overvoltage protective device is connected to two ends of a ground resistor of the converter transformer valve side in parallel and used for acting to lead failure current away, restraining the level of overvoltage of an alternating current circuit I (4) and protecting a converter valve body (9) when overvoltage of a direct current circuit (8) exists due to a fault of the alternating current circuit I (4) or a fault of the direct current circuit (8) or a valve base controller detects the phenomenon that the alternating current circuit I (4) breaks down. The protective device is rapid in action, strong in through-flow capacity, large in absorbed energy, and capable of rapidly protecting the valve body. A control protective device with a complicated structure and complicated functions is not needed. The overvoltage protective device is simple in structure, low in cost and easy to implement, reduces the cost of the alternating current and insulation cost of a converter valve, guarantees safety of the alternating current circuit and the converter valve, improves fault-resistance ability of a converter station, and guarantees safe and stable operation of the voltage source converter high voltage direct current transmission system.

A method for detecting potential failures by a lead of an implantable medical device is provided. The method includes sensing a first signal over a first channel between a first combination of electrodes on the lead and sensing a second signal from a second channel between a second combination of electrodes on the lead. The method determines whether at least one of the first and second signals is representative of a potential failure in the lead and identifies a failure and the electrode associated with the failure based on which of the first and second sensed signals is representative of the potential failure. Optionally, when the first and second sensed signals are both representative of the potential failure, the method further includes determining whether the first and second sensed signals are correlated with one another. When the first and second sensed signals are correlated, the method declares an electrode common to both of the first and second combinations to be associated with the failure.

Disclosed are elevated lights and methods of maintaining illumination in elevated lights for an airfield. The elevated lights have a substrate having a mounting surface, LEDs, a reflector, and an LED driver circuit. The LEDs are disposed on the mounting surface of the substrate and configured such that a primary illumination axis of each LED is oriented along a longitudinal axis of the elevated light. The reflector is configured such that the light emitted from the LEDs is reflected radially with respect to the longitudinal axis of the elevated light. The driver circuit is configured to provide a current to the LEDs and detect failure of one or more of the LEDs. Illumination is maintained by providing a current to the LEDs, detecting a voltage change across the LEDs, determining, based on the voltage change, LED failure, and altering the provided electrical current in order to maintain illumination.

A method and system for the diagnosis of anomalies in a lead attached to an implantable medical device, such as an implantable cardioverter defibrillator (ICD), including an insulation breach resulting in a short circuit of the high-voltage shock pulse. Determination that the defibrillation pathway is shorted may be made by initial analysis of a Reference EGM and Diagnostic EGM and subsequent analysis of Differential Diagnostic EGMs. Upon determining if a specific defibrillation pathway is shorted, the nonessential defibrillation electrode of that pathway may be excluded from the defibrillation circuit, delivering defibrillation current only between functioning defibrillation electrodes. Alternatively, the ICD system can confirm the presence of a lead anomaly with one or more alternative diagnostic approaches. Patient and remote-monitoring alerts may be initiated.

A fault protected current source is provided that can be used to safely drive LEDs in reliability test systems. The current source is includes circuits and processes that detect the common faults found in LED reliability test systems. After a fault is detected, the current source shuts down drive before destructive spikes are produced. Because only true LED failures are counted, this fault protected current source can be used to construct reliability test systems that produce more accurate reliability test data.

Disclosed is an LED failure detection system. The LED failure detection system comprises a power module, a switch unit, an LED lamp set, a voltage detection unit, a control unit and an output filtering unit. The power module is respectively connected with the switch unit, the LED lamp set, the voltage detection unit, the control unit and the output filtering unit through a voltage stabilization unit, the output end of the output filtering unit is connected with the input end of the control unit, the output end of the control unit is connected with the input end of the switch unit, the first output end of the switch unit is connected with the LED lamp set, the second output end of the switch unit is connected with the output filtering unit, and the LED lamp set is connected with the control unit through the voltage detection unit. The LED failure detection system can effectively perform LED failure detection on an LED and can ensure that the failure number of LEDs in an LED array can be effectively counted no matter the LEDs are at open circuit failure states or at short circuit failure states.