Motorola Corporation

Temic Automotive of North America, Inc.

Edward E Li

Dennis L Stephens

Guang Rong Liu

Anand K Upadhyay

Ralph M Mitchell

Leonard Foss

David Cousins

Randall C Gray

John E Herrmann

Robert B Jarrett

Sameer Sodhi

Sang Hoon Kim

Mark Paul Lill

Koushun Sun

Robert M Hess

John H Aseltine

Mark Gunderson

Wen Li

An improved circuit and method for detecting dielectric breakdown and ground fault conditions is provided. The circuitry and method of the present invention include taking a continuous voltage reading of the high voltage battery and sampling the continuous voltage reading of the high voltage battery at a fixed time interval. The circuitry and method calculate a change in the continuous voltage reading of the high voltage battery over the change in time and repeatedly calculate an optimum fixed time interval and an optimum change in voltage over time. Storage of the optimum fixed time interval and optimum change in voltage over time provides for repeatedly comparing the optimum change in voltage over the fixed time interval to the constant voltage of the high voltage battery to calculate the resistance of the dielectric breakdown fault. The calculation of the resistance of the dielectric breakdown fault is carried out independently of the capacitance of the electric circuit. The circuit and method provide adjustment of the optimum fixed time interval to improve the speed of the comparison of the optimum change in voltage over time to the constant voltage of the high voltage battery to calculate the resistance of the dielectric breakdown fault.

Circuit and method for detecting a dielectric breakdown fault

A method (100) of controlling an inverter in an electronic ballast for at least one gas discharge lamp protects the inverter from damage due to lamp fault conditions, and provides enhanced noise immunity and multiple ignition attempts for low-temperature lamp starting. The method (100) includes repeating a filament preheating step and a frequency shifting step up to a predetermined number of times in order to facilitate lamp ignition under low-temperature conditions and to verify the legitimacy of a detected lamp fault.

Inverter control method for electronic ballasts

An electronic ballast (300) for powering at least one gas discharge lamp (10) includes an inverter (400), an output circuit (700), a lamp fault detection circuit (800), and an inverter control circuit (500). Ballast (300) operates according to an inverter control method (100) that includes repeating a filament preheating step and a frequency shifting step up to a predetermined number of times in order to facilitate lamp ignition under low-temperature conditions and to verify the legitimacy of a lamp fault. Inverter control circuit (500) is well-suited for implementation as a custom integrated circuit. Ballast (300) optionally includes an overcurrent detection circuit (820') with an adjustable lamp fault detection threshold that provides decreased sensitivity during lamp starting and enhanced protection after lamp ignition.

Electronic ballast with inverter control circuit

An electronic ballast (10) comprising an AC-to-DC converter (100), an inverter (200), an output circuit (400), a high-voltage detection circuit (500), and a no-load detection suit (600). The inverter (200) includes an inverter control circuit (300) that monitors the lamp(s) via the high-voltage detection circuit (500) and the no-load detection circuit (600), and that terminates inverter switching in response to various lamp-fault conditions such as 'diode-mode' behavior. Inverter control circuit (300) also provides for automatic ignition of a replaced lamp and may be economically implemented as a single integrated circuit.

Electronic Ballast with inverter protection circuit

An improved battery charger apparatus and method with multiple range current control includes a programmable current source (101) for providing a charge current (105) to charge a battery (107). An amplitude of the charge current (105) is dependent on a charge demand signal (117) supplied to the programmable current source (101). A scaler (109) provides a scaled charge current signal (111), dependent on the charge current (105) and a current range signal (113). A charge current control unit (115) regulates the charge current (105) by providing the charge demand signal (117) to the programmable current source (101) dependent on the scaled charge current signal (111). More than one amplitude of the charge current (105) is provided to the battery (107), dependent on more than one current range signal (113) provided by the charge current control unit (115) to the scaler (109). Moreover, a constant amplitude of the scaled charge current signal (111) is maintained responsive to the more than one current range signal (113).

Battery charger apparatus and method with multiple range current control

An electric motor control with integral battery charger includes battery terminals (201) for connection to a battery (203). A boost converter circuit (111) is coupled to an armature winding (209) of the electric motor (117), and has an input (131) coupled to a power source (211). A buck converter circuit (105) is coupled to a field winding (207) of the electric motor (117), and an input (133) coupled to the power source (211). A controller (205), is coupled to the battery terminals (201) and the power source (211). The controller (205) couples a boost output (107) of the boost converter circuit (111 ) to the battery terminals (201) while a terminal voltage of the power source (211) is lower than a terminal voltage of the battery (203) measured at the battery terminals (201), and couples a buck output (107) of the buck converter circuit (105) to the battery terminals (201 ) while the terminal voltage of the power source (211) is higher than the terminal voltage of the battery (203).

Electric motor control with integral battery charger

A DC power switch (10) for a capacitive load (11) has a main transistor (Q1) in series with the load between positive and negative DC bus terminals (B.sup.+, B.sup.-). A secondary transistor (Q2) and a resistor (R.sub.1) are connected in series and this series connection is connected in parallel to the main transistor (Q1). A control circuit (20; 50) is connected to the main and secondary transistors (Q1, Q2) and controls them. In response to an enable signal (26), the secondary transistor (Q2) is initially turned on such that it and the resistor provide the initial charging current for the capacitor load (11) and subsequently the secondary transistor is turned off and the main transistor is turned on such that it provides the subsequent current required by the load. This configuration minimizes the power dissipation ratings required for the transistors while balancing this requirement with the relative rapid providing of charging current for the capacitive load. Fault detection circuitry (30-33) makes sure both the main and secondary transistors are off and interrupts the supply of DC power to the load (11) in the event of a detected fault.

DC power switch with inrush prevention

A technique for detecting misfire due to a fault in the secondary of an automotive ignition system compares the ignition signal developed by the ignition coil, preferably the primary winding thereof, to reference signals. Abnormal results which occur at predetermined times subsequent to the initiation of the ignition signal indicate short circuit and/or open circuit conditions in the ignition system's secondary. In response to such fault conditions, fuel is preferably shut off to the cylinder associated with the misfire.

Ignition misfire detector

Disclosed is an ignition signal control apparatus and method for a distributorless ignition system of the type having a sensing circuit which generates at least one reference signal which may be used to periodically indicate when ignition spark plugs should be fired, and at least one identifier signal determinative of the engine's crank angle position to identify the spark plug firing sequence. One aspect of the invention includes detecting that a transition in the identifier signal has not occurred, and generating a replacement signal independent of the crank angle position, to select one or more of the spark plugs to fire.

Apparatus and method for electronic ignition control

An improved comparator circuit of the type which includes first and second differential PNP transistors operating in conjunction with a current mirror circuit includes an additional dual collector PNP transistor. That is, while the reference voltage is applied to the base of one of the differential transistors, the input voltage to be compared with the reference voltage applied to the emitter of the dual collector's transistor which has a first collector coupled to the base of the other differential transistor. The second collector is coupled to the base of the additional transistor. In this manner, should the input voltage fall below the substrate voltage, the additional transistor will be reverse biased thus preventing the parasitic diode at the base of the second differential transistor from turning on.

Comparator with substrate injection protection

An invention for detecting loss of input signals to a distributorless ignition system (17) and for providing appropriate responses upon detecting fault conditions. If a SPOUT signal (31) faults low, the invention will control ignition sequence through use of a CID signal (14), and the CID signal (14) and a PIP signal (13) will be operably substituted for the missing SPOUT signal (31) to assure timely ignition. If the SPOUT signal (31) faults high, the CID signal (14) will again be utilized to sequence the firing sequence and the PIP signal (13) will be substituted for the SPOUT signal (31). If the CID signal (14) faults, firing sequence will continue to be incremented in response to receipt of the SPOUT signal (31). In addition, the invention provides for recovery of normal operation should any of the above fault conditions prove to be transient.

Loss of input signal detection and response system for use with

An overcurrent protection circuit for inductive loads such as motors is provided. A source voltage is input to a divider circuit including semiconductor switching devices. The inductive load is also connected to the voltage source through the divider circuit. A voltage output from the divider circuit which is proportional to the current through the inductive load is input to a comparator circuit. Another input to the comparator circuit comprises a reference voltage selected to correspond to the maximum desired current through the inductive load. If the comparator circuit senses that the current through the inductive load is greater than the predetermined maximum current, it provides an output to a pulse generator device. The output from the pulse generator device is input to a switching circuit which can cut off the voltage source supply to the inductive load.

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Roselle, IL, United States of America

Edward E Li