United Technologies Automotive Inc.

United Technologies Corporation

Essex Group, Inc.

David L Juzswik

William M Floyd

Nathaniel Webb

Bruce R Wrenbeck

John E Lahiff

An improved current sensing circuit is provided in, or for use with, a power delivery circuit having a current controlling device of the type which includes auxiliary current sensing terminals. The current sensing circuit is particularly useful in conjunction with a respective current sensing power MOSFET located in the 'high side' of a switching circuit, such as an H-bridge switch for a bidirectional load. The current sensing circuit has two branches connected to the current sensing MOSFET and to a reference potential and constructed to provide an output voltage signal representative of the main current through the current sensing MOSFET. The first branch includes at least two transistors and a resistor serially connected between a current sense terminal of the MOSFET and a reference potential. The second branch also includes at least two serially connected transistors connected between a terminal of the MOSFET and the reference potential. The transistors are cross-connected between branches and provide an inverted current mirror and a current mirror. Fifth and sixth transistors may also be included as part of the current sensing circuit.

Device in a power delivery circuit

A power delivery circuit for supplying load current to a load includes a current switch connected on the high potential side of a load. In order to detect a current condition, such as an over-current condition in the load, a current sensing and detection circuit preferably cooperates with the current switch wherein such switch comprises a multicellular device with a plurality of terminals. Such terminals include a first main current terminal connected to a source of high potential, a second main current terminal connecting a majority of device cells to the load, a first auxiliary terminal connected at one end to a minority of device cells so as to provide a current generally proportional to the main device current, and a second auxiliary terminal connected at one end to a majority of device cells. The current detection circuit preferably comprises one branch connected between the first auxiliary terminal and ground and including, in serial circuit, a current-to-voltage converting resistor providing a voltage at one end approximately proportional to the main device current and a bias signal-controlled transimpedance device, and another branch connected between the second auxiliary terminal and ground and providing a bias signal for the transimpedance device in the first branch.

Power delivery circuit with current detection

Current sensing circuit for use with a current controlling device in a

A drive circuit is provided for a bidirectional DC inductive motor, as may be used for automotive window wipers and the like. Four power MOSFETS are connected in an H-bridge configuration with the motor and a DC source. A pair of input terminals receives respective direction-controlling logic signals. Respective intermediate switching circuits are connected between each input terminal and the high-side and low-side power MOSFETS connected to the same motor terminal for controlling those two power MOSFETS in a complementary manner. A braking signal may also be applied to the input terminals. A third terminal receives a pulse-width modulated control signal and extends it, via appropriate circuitry, to an appropriate one of the low-side power MOSFETS for speed regulation. The values of certain components of the drive circuitry are selected to minimize cross-conduction between certain power MOSFETS and to optimally accommodate the inductive effects of the motor and leads.

Bidirectional motor drive circuit

An improved control system is provided for controlling the variable characteristic associated with automotive peripheral devices, such as seats, mirrors, seat bladders or the like, having a 'memory' capability. The control system avoids overloading a central controller and/or a data link between the central controller and the device being controlled, by approximating the 'run' interval required to vary the relevant characteristic, i.e. seat position, from its present value to a target value recalled from memory. Pulses are generated by variations in the seat position and accumulated in a counter which may be separate from the central controller. At the completion of a 'run' for the approximated interval, the accumulated count is used to update a count representative of the 'present' seat position. The updated position is again compared to the target position and, if it differs by more than some acceptable tolerance, a new interval is determined and is 'run'. Provision may be made to compensate the determination of the interval for changes in the rate at which the seat responds.

Multiplex control system for memory seat or the like load

A control system, as for controlling automotive body functions, is powered by a limited capacity electrical power source and is structured and controlled in a manner to minimize consumption of electrical power. The control system conducts data transactions between a central control station and one or more remote controllers connected therewith, and the central control station includes a provision for electronic signal processing for controlling the data transactions with the remote controllers. A power FET is operatively connected to the power source and to a portion of the control system for selectively connecting or disconnecting power to that control system portion. The system employs a NMOS microprocessor. The portion of the control system from which power may be disconnected will typically include the processor. The level of system activity is monitored and a power-down, or 'sleep' control signal is automatically provided if a predetermined condition of inactivity occurs. That power-down control signal is operatively applied to certain control circuitry for in turn causing the power switch to disconnect power when the power-down control results. Correspondingly, a timer, which preferably is continuously powered, times a 'sleep' interval during which power is disconnected from the relevant control system portion and generates a power-up control signal at the end of some predetermined time. The control circuitry responds to this power-up control signal by causing the power switch to reapply power to the previously disconnected portions of the control system.

Power-conserving control system for turning-off the power and the

A window wiper control system provides accurate regulation and/or profiling of wiper speed. A desired interval corresponding with the preselected speed or speed profile is stored; a reference signal is provided to indicate a reference position of the wiper and is used to measure the actual interval of a wiper stroke or cycle. The actual interval is compared with the desired interval and an appropriate adjustment is made in a pulse-width modulation signal for effecting a desired speed and interval. The pulse-width modulation signal preferably has a relatively-low repetition rate. The wiper speed may be profiled to include acceleration and deceleration, and the intervals of acceleration and deceleration may be lengthened substantially to provide an apparent dwell.

Speed control for a window wiper system

An electrical power delivery system and method of operation particularly suitable for use in a vehicle is disclosed. A single wire power conductor is connected through remote power switches to a plurality of loads. The power conductor is sized such that its current-carrying capacity is less than the current required to simultaneously operate all the loads connected thereto. Logic means are provided for delivering a control signal to the remote power switches to selectively energize the appropriate loads. The logic means additionally includes means responding to excess current flow through the power conductor to schedule the control signals to prevent simultaneous operation of all the loads thereby limiting current flow through the power conductor to its current-carrying capacity.

Load current management system for automotive vehicles

A control circuit is provided for selectively determining multiple modes of operation for one or more electrical loads in an automotive accessory system. For a particular load, the circuit includes a switch and a microcomputer signal processing unit. The switch is typically of the momentary-action, dry type which provides a signal only so long as an actuating force is applied. The microcomputer repetitively, at brief intervals determines the presence or absence of such a signal indicative of switch actuation and further is responsive to either brief 'momentary' actuation of the switch to effect a primary mode of load control or to a longer 'dwell' actuation to effect a secondary mode of load control. The secondary mode of load control includes a characteristic which is determined as a function of the 'dwell' duration. Such characteristics of load control in the second mode include the duration of actuation of directional lane-change lamps, the interval between sweeps of a windshield wiper operating intermittently and/or the intensity or brightness of illumination lamps.

Control circuit for automotive accessory system

A serial data communications system, particularly for use in an automotive environment is disclosed in which bidirectional serial data communication is effected between a central control station and one or more remote stations with high integrity. The central control station includes a central controller and at least two multiplex controllers. A serial signal bus is arranged as a loop connected at its opposite ends to respective ones of the two multiplex controllers. A remote multiplex controller, located at each of the remote stations, includes input/output signal ports for input and output, respectively of signals respectively from and to remote input devices and remote load devices. Each remote multiplex controller is parallel 'T' connected to the serial bus intermediate its end terminals, has a respective address, and is responsive to a serial communication containing its respective address from the central control station for providing a response to the communication. The central controller selects one of the multiplex controllers to be the master in accordance with a preselected bias, and selects the other of the multiplex controllers to be the master when data communication of acceptable integrity with an addressed one of the remote controllers by the designated master multiplex controller is unattainable.

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Dearborn Heights, MI, United States of America

David L Juzswik