Delphi Technologies, Inc.

Delco Electronics Corporation

Scott Birk Kesler

Mark Wendell Gose

Jerral A Long

John R Fruth

Raymond O Butler, Jr

John W Boyer

Duane E Beyler

Philip Allen Karau

John Robert Shreve

Philip Ralph Peterson

Daniel J O'Connor

Gregg Nelson Francisco

Michael Joseph Huemmer

Thomas L Dinkledine

A system and method for operating a power transistor. Parasitic impedances naturally present in a circuit board or other interconnect structures exhibit a parasitic impedance effective to generate a parasitic voltage signal in response to operating the power transistor. The parasitic voltage signal is monitored in order to better control the power transistor. In particular, the threshold voltage of the power transistor can be determined and used to more optimally control the power transistor.

Threshold voltage based power transistor operation

A switching control system and method is provided that optimizes switching efficiencies for power switching applications including automotive ignition systems, solenoid drivers, motor drivers and power regulation systems. In an ignition system, a coil current switching magnitude is controlled at the start of ignition coil charging, thereby avoiding an untimely spark event. When the transistor threshold voltage is reached, the collapse rate of the ignition system transistor collector voltage is reduced by reducing the gate charging current. The reduced collector voltage slew rate results in a reduced primary and secondary coil output voltage. After the collector voltage collapses, a continued rapid charge is provided to place the transistor in a hard saturation bias condition. In an aspect, the present invention dynamically determines the threshold voltage of a power transistor. A mirror capacitor substantially matches a transistor gate voltage and a signal is generated when the mirror capacitor voltage proportionally exceeds the transistor gate voltage as a consequence of the transistor reaching a threshold voltage.

Switching control system to reduce coil output voltage when commencing coil charging

An analog, duty cycle replicating frequency converter extracts duty cycle information from an input, pulse width modulated signal and generates an output pulse width modulated signal of the same duty cycle at a different frequency without regard to the frequency of the input signal. It uses bipolar transistor based circuitry, adaptable to an application specific integrated circuit, to derive voltages representing the on-time and period durations of the input signal, convert these voltages to currents representing the logarithms thereof, generate a voltage representing the difference between the currents, exponentially convert the voltage to a current representing the duty cycle and control an oscillator to generate an output pulse width modulated signal at a predetermined frequency with the duty cycle of the input signal.

Analog duty cycle replicating frequency converter for PWM signals

Drive current stabilization is achieved through the management of a drive current. The drive current may include a control current that is provided to a control terminal of a switch, a current limit input current that is provided to a current limit circuit associated with the switch and a stabilization current. The switch carries a load current responsive to a control signal on the control terminal. The magnitude of the control current is monitored and a magnitude of the stabilization current is increased responsive to a decrease in the magnitude of the control current to substantially maintain a magnitude of the drive current.

Technique for drive current stabilization of an automotive ignition system

An ignition control circuit () is responsive to a control signal (ESTC) to apply a drive signal (GD) to a power switching device () to conduct ignition coil current (I) therethrough. A resistor (R) included within the circuit () receives, and dissipates heat generated by, the coil current (I). The circuit () includes a first transistor (Q) positioned adjacent to the resistor (R) such that an operating temperature thereof is near that of the resistor (R), and a second transistor (Q) positioned remote from the resistor (R) and having an operating temperature defining a reference temperature. The first and second transistors (Q, Q) are configured to produce an output voltage (V) proportional to a difference in operating temperatures thereof, and a latch circuit (L) disables the control signal (ESTC) to thereby turn off the power switching device () when the output voltage (V) difference exceeds a reference voltage (V).

Over-dwell protection circuit for an automotive ignition control system

Thermal overload protection circuitryfor an automotive ignition system includes a gate drive circuit () responsive to a control signal (ESTB) to produce a drive signal (V) for driving a power switching device () separate from the protection circuitry (), and a thermal overload protection circuit () configured to supply a first current (I) to a thermal sensing component () associated with, and having an operating temperature defined by, the power switching device (), wherein the first current (I) has a magnitude defined by the operating temperature of the thermal sensing component (). The first current is multiplied by a current controlled current source () to produce a second current (I), and the second current is used to limit the drive signal (V) to thereby maintain the operating temperature of the power switching device () below an operating temperature limit.

Thermal overload protection circuit for an automotive ignition system

A technique for reducing input currents associated with a comparator circuit during certain events includes minimizing bias currents associated with the comparator circuit when a magnitude of an input signal at a signal input of the comparator circuit is a predetermined value from a magnitude of a reference signal applied to a reference input of the comparator circuit. The bias currents are increased when the magnitude of the input signal is within the predetermined value of the magnitude of the reference signal.

Automotive ignition system with battery dependent over-dwell protection

An interface for providing thermal overload protection includes a switching device, a temperature indicating device, a drive circuit and a thermal monitoring circuit. The thermal monitoring circuit is coupled across the temperature indicating device and provides a shutdown signal to the drive circuit when the temperature of the switching device is above a predetermined temperature level as indicated by a temperature signal provided by the temperature indicating device. The drive circuit responds to the shutdown signal by removing current sources and current sinks from a control terminal of the switching device at which point leakage currents cause the switching device to reduce a drive current to an inductive load.

Automotive ignition system with sparkless thermal overload protection

An automotive ignition diagnostic system includes an ion current detection circuit producing a buffered representation of an ion current flowing across an electrode gap of an ignition plug in response to a bias voltage applied thereto. An ignition diagnostic circuit is responsive to the buffered representation of the ion current to charge a single integration capacitor. The diagnostic circuit is operable to produce an output signal having a pulse width defined by the amount of charge on the capacitor. When the ion current flows following a combustion event, the width of the output signal is controlled as a function of the quality of combustion in the corresponding cylinder. However, if sufficient ion current flows prior to combustion, the width of the output signal is controlled to indicate a fouled ignition plug.

Automotive ignition monitoring system with misfire and fouled plug detection

An integrated circuit () includes a thermal sensing device () and a power-switching device () such as an IGBT. The power device () is fabricated in a conventional manner on a semiconductor substrate, and the thermal sensing device () is fabricated on an electrical insulation layer () formed over the substrate. The thermal sensing device () may be provided in the form of a number of series-connected polysilicon diodes (D-D) positioned adjacent to the power device () such that the operating temperature of the thermal sensing device () is near that of the power device (). In response to an input current I, the thermal sensing device () produces an output voltage (V) that is substantially linear with surface die temperature, and which reacts rapidly to changes in surface die temperature. The thermal sensing device () is completely electrically isolated from the power device, thereby eliminating any electrical interaction therebetween.

Integrated circuit including semiconductor power device and electrically isolated thermal sensor

In an ignition coil assembly of an ion sensing ignition system having an ignition coil output, a buffered ion-sense current source circuit is provided and includes a current sensing circuit, the current sensing circuit being disposed so as to be communicated with the ignition coil output and an active current source circuit, the active current source circuit being disposed so as to be communicated with the current sensing circuit and a current measuring device.

Buffered ion sense current source in an ignition coil

An automotive ignition system ( ) includes a control circuit ( ) operable to drive a coil current switching device ( ) connected between an ignition coil ( ) referenced at battery voltage (V ) and a sense resistor (R ) referenced at ground potential. The control circuit ( ) includes a drive circuit ( ) and voltage trip circuit ( ) defining a reference voltage (V ) for comparison with a sense voltage (V ) developed across the sense resistor (R ) due to increasing coil current (I ) through the ignition coil ( ). As the sense voltage (V ) increases to the reference voltage (V ), the voltage trip circuit ( ) produces a trip voltage signal (V ) to which the drive circuit ( ) is responsive to deactivate the coil current switching device ( ). The voltage trip circuit ( ) is configured such that the reference voltage (V ) is temperature and battery voltage, and optionally engine speed, dependent. The trip voltage signal (V ) thus carries this same dependency so that ignition coil charging time may be. optimally controlled under varying temperature, battery voltage, and optionally engine speed, conditions.

Ignition control circuit providing temperature and battery voltage compensated coil current control

An automotive ignition system includes a control circuit ( ) operable to drive a coil current switching device ( ) connected to an ignition coil ( ) referenced at battery voltage. The control circuit ( ) includes a drive circuit ( ) and ring damping circuit ( ) producing an inhibit signal (INH) to which the drive circuit ( ) is responsive to control the state of the coil drive signal (GD). In a single pulse ignition system; i.e., an ignition system employing a single coil charging event per combustion cycle, the ring damping circuit ( ) is responsive to a spark control signal (ESTBF) to control charging and discharging of a single capacitor (C ) to define the inhibit signal (INH). In a multiple pulse ignition system; i.e., an ignition system employing multiple coil recharging cycles following a standard initial charging dwell cycle, the ring damping circuit ( ) is responsive to the spark control signal (ESTBF) and at least two mode signals (M M ) to control charging and discharging of the single capacitor (C ) throughout the initial and subsequent coil charging cycles to define the inhibit signal (INH). In either case, the drive circuit ( ) is responsive to the inhibit signal (INH) to disable current flow through the primary ignition coil ( ) when the inhibit signal (INH) is enabled, and to enable current flow through the primary ignition coil ( ) when the inhibit signal (INH) is disabled.

Automotive ignition system with adaptable start-of-dwell ring damping

A compensation circuit provides a compensation current to a node of an integrated circuit that experiences increased reverse-bias leakage current between a n-type leaking epitaxial region and a p-type substrate with increased temperature. The compensation circuit includes a p-type substrate, a n-type compensator epitaxial region, an contact region, a center p-type region and a plurality of peripheral p-type regions. The peripheral p-type regions function as either a node collector or a reference collector. The compensation current is substantially determined by the ratio of the total peripheral surface area facing the center p-type region associated with the node collector and the total peripheral surface area facing the center p-type region associated with the reference collector and is also determined by the total surface area of the n-type compensator epitaxial region.

Leakage current compensation circuit

An ignition system for an internal combustion engine includes an ignition coil coupled to a spark plug in a combustion chamber of the engine, and a switch responsive to an ignition control signal for causing a primary current to flow through a primary winding of the ignition coil. A control circuit is configured to generate the ignition control signal so as to produce a plurality of sparks at the spark plug during a combustion event in the cylinder. A combustion detection circuit in sensing relation with the combustion cylinder is configured to generate a combustion detect signal when combustion occurs. The control circuit is further configured to terminate the generation of the ignition control signal during the combustion event in response to the combustion detect signal, thereby terminating multicharge operation when the need for further sparks is no longer present. Unnecessary spark plug wear is avoided.

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Kokomo, IN, United States of America

Scott Birk Kesler