A power semiconductor has power terminals arranged in a row at one side of the housing, with control terminals arranged in a row at the other side of the housing. The spacing between adjacent power terminals is greater than the spacing between adjacent control terminals.

A portable electronic device includes an electronic module and an electronic module fixing structure. The electronic module fixing structure includes a main body, a sliding component, a rod and an elastic component connected between the main body and the sliding component. The main body has a track with a positioning portion. The sliding component is slidably disposed on the main body. The rod is rotatably connected with the sliding component. An end of the rod is adapted to move along the track. When the end is located at the positioning portion, the end and the positioning portion are interfered with each other to position the sliding component. When the electronic module pushes the sliding component, the rod is rotated to drive the end to move away from the positioning portion, and the sliding component pushes the electronic module away from the main body through elastic force of the elastic component.

An electronic device may be provided with a printed circuit board having padded through-holes. The padded through-holes may be formed from openings in a printed circuit board substrate and elastomeric members in the openings. The elastomeric members may be conductive elastomeric members such as electrically or thermally conductive elastomeric members. The printed circuit board may be secured within a housing for the electronic device using engagement members that extend through padded through-holes. The engagement members may engage with the housing or with additional engagement members that are attached to the housing. The electronic device may include a cowling structure formed over electronic components on a surface of the printed circuit board. The cowling structure may be secured to the printed circuit board using attachment members that engage with the engagement members in the padded through-holes.

Disclosed herein is a display device including a main board part configured to have a display area including drive wiring and have a display panel disposed in the display area; and an auxiliary board part configured to be monolithic with the main board part and have extraction wiring from the drive wiring.

A mounting structure of a flexible printed circuit board and a sliding-type electronic device is provided by which a too large increase in thickness of devices can be avoided and a pair of housings can be slid relatively in a bending and slanting direction. In the mounting structure, an upper housing 12 and a lower housing 22 coupled in a freely slidable manner are electrically connected to each other by a flexible printed circuit board folded back to be routed between slide facing surfaces 12b and 22a of both the housings and the height of a side wall surface 12c and 22c of the upper housing and lower housing changes in a bending manner along the direction of freely sliding and, in the slide facing surfaces of the upper housing and lower housing, concave space portions 15 and 25 to accommodate the change in curvature and in position of a folding-back portion 31a caused by sliding motion between the upper housing and lower housing are disposed.

A positioning structure for a removable hard drive includes an enclosure and a tray. The enclosure is used for being mounted by the hard drive, and disposed with a plurality of positioning holes. The tray includes a bottom and two side walls vertically extending therefrom. A space being is formed by the bottom and the side walls. The bottom is formed with a plurality of positioning pillars corresponding to the positioning holes. The enclosure is received in the space, and the positioning holes are correspondingly inserted by the positioning pillars.

A converter power unit comprises: a heat sink; n power switch modules on the heat sink; a first group of laminated bus bars comprising a first and a second bus bar; a capacitor group comprising m capacitor; a second group of laminated bus bars comprising a third and a fourth bus bar, the first bus bar is connected with the third bus bar, the second bus bar is connected with the fourth bus bar; providing that vertical projection areas projected by an area occupied by the n power switch modules and projected by the capacitor group on a first plane perpendicular to an axial direction of the capacitor group are defined as a first and a second projection areas respectively, the first and the second projection area have an overlapped area. The present application can reduce the stray inductances in the commutating loop of the converter.

An electronic component includes an interposer, and a multilayer ceramic capacitor. The interposer includes a substrate including front and back surfaces that are parallel or substantially parallel to each other. Two first mounting electrodes and two second mounting electrodes are located on the front surface of the substrate, on opposite end portions in the longitudinal direction. Recesses are located in the longitudinal side surface of the insulating substrate. Connecting conductors are each provided in the side wall surface of each of the recesses. The connecting conductors connect a first external connection electrode and a second external connection electrode that are located on the back surface of the substrate, and first mounting electrodes and second mounting electrodes.

An apparatus includes a first substrate having a first land and a second substrate having a second land. A first molding compound is disposed between the first substrate and the second substrate. A first semiconductor chip is disposed on the first substrate and in contact with the first molding portion. A first connector contacts the first land and a second connector contacts the second land. The second connector is disposed on the first connector. A volume of the second connector is greater than a volume of the first connector. A surface of the first semiconductor chip is exposed. The first molding compound is in contact with the second connector, and at least a portion of the second connector is surrounded by the first molding compound.

A semiconductor device effectively suppress the problem of mutual interaction occurring between an inductor element and wires positioned above the inductor element formed over the same chip. A semiconductor device includes a semiconductor substrate and a multi-wiring layer formed overlying that semiconductor substrate, and in which the multi-wiring layer includes: the inductor element and three successive wires and a fourth wire formed above the inductor element; and two shielded conductors at a fixed voltage potential and covering the inductor element as seen from a flat view, and formed between the inductor element and three successive wires and a fourth wire formed above the inductor element.

According to one embodiment, a television receiver includes: a housing; a circuit board arranged in the housing; an electronic component mounted on the circuit board; a reinforcing member comprising a first surface in contact with the circuit board, and a second surface located on an opposite side of the first surface and exposed to an inside of the housing; a component contained in the housing, the component comprising a first supported area located at a distance from a surface of the circuit board; and a support member configured to support the component, the support member comprising a first end portion fixed to the first supported area of the component, and a second end portion fixed to the second surface of the reinforcing member.

A lightweight radio/CD player for vehicular application is virtually “fastenerless” and includes a case and frontal interface formed of polymer based material that is molded to provide details to accept audio devices such as playback mechanisms (if desired) and radio receivers, as well as the circuit boards required for electrical control and display. The case and frontal interface are of composite structure, including an insert molded electrically conductive wire mesh screen that has been pre-formed to contour with the molding operation. The wire mesh provides EMC, RFI, BCI and ESD shielding and grounding of the circuit boards via exposed wire mesh pads and adjacent ground clips. The major components and subassemblies self-interconnect by integral guide and connection features effecting “slide lock” and “snap lock” self-interconnection. The major components and subassemblies self-ground by establishing an interference fit with exposed, resilient, embossed portions of wire mesh.

An apparatus for reducing EMI at the micro-electronic-component level includes a substrate having a ground conductor integrated therein. A micro-electronic component such as an integrated circuit is mounted to the substrate. An electrically conductive lid is mounted to the substrate, thereby forming a physical interface with the substrate. The electrically conductive lid substantially covers the micro-electronic component. A conductive link is provided to create an electrical connection between the electrically conductive lid and the ground conductor at the physical interface.

A power inverter includes a power semiconductor module that includes a power semiconductor device, a control circuit board that outputs a control signal used for controlling the power semiconductor device, a driver circuit board that outputs a driving signal used for driving the power semiconductor device, a conductive metal base plate arranged in a space between the driver circuit board and the control circuit board in which a fine and long opening portion is formed, wiring that connects the driver circuit board and the control circuit board through the opening portion and delivers the control signal to the driver circuit board, and an AC busbar that is arranged on a side opposite to the metal base plate through the driver circuit board and delivers an AC current output from the power semiconductor module to a drive motor. At least a portion of the AC busbar that faces the opening portion extends in a direction directly running in a longitudinal direction of the fine and long opening portion.

An arc detection and intervention system for a solar energy system. One or more arc detectors are strategically located among strings of solar panels. In conjunction with local management units (LMUs), arcs can be isolated and affected panels disconnected from the solar energy system.

The electronic component has a resin electrode which constitutes an external electrode on a face of a ceramic base body. At least a tip portion of a resin electrode region extended around another face of the body is bonded to the ceramic base body, and further a relationship between Rz1 and Rz2 satisfies the following requirement: Rz1>Rz2, Rz1>3.3 μm, and Rz2

Disclosed herein is a mounting structure of a circuit board having a multi-layered ceramic capacitor thereon. The mounting structure of a circuit board having a multi-layered ceramic capacitor thereon, in which a dielectric layer on which inner electrodes are disposed is stacked and external electrode terminals connecting the inner electrodes in parallel are disposed on both ends thereof, wherein the inner electrodes of the multi-layered ceramic capacitor and the circuit board are disposed so as to be a horizontal direction to connect the external electrode terminals with a land on the circuit board by a conductive material and a ratio of a bonding area ASOLEDER of the conductive material to the area AMLCC of the external electrode terminals AMLCC is set to be less than 1.4, thereby remarkably reducing the vibration noise.

An electronic component, preferably in the form of a laminated ceramic capacitor, which suppresses the growth of whiskers and has excellent solderability, includes an electronic component element in the shape of, for example, a rectangular parallelepiped. External electrodes of terminal electrodes are located on first and second end surfaces of the electronic component element. First plated films including plated Ni are located on the surfaces of the external electrodes. Second plated films are located on the surfaces of the first plated films. The second plated films have stacked structures including first plated layers and second plated layers. The second plated layers have lower degrees of densification than the first plated layers.

An apparatus includes a case capable of receiving a plurality of capacitive elements, each capacitor element having at least two capacitors, and each capacitor having a capacitive value. The apparatus also includes a cover assembly with a peripheral edge secured to the case. The cover assembly includes, for each of the plurality of capacitive elements, a cover terminal that extends upwardly from the cover assembly generally at a central region of the cover assembly. Each cover terminal is connected to one of the at least two capacitors of the respective one of the plurality of capacitive elements. The cover assembly also includes, for each of the plurality of capacitive elements, a cover terminal that extends upwardly from the cover assembly at a position spaced apart from the cover terminal generally at the central region of the cover assembly.

An electrostatic discharge (ESD) protection circuit is provided. The ESD protection circuit includes an impedance device coupled between a pad and a power line and a clamp unit coupled between the pad and a ground line.

A brake system and related components including a metering device are configured to regulate a control signal received from a brake control device such that a control valve delays the supply of a level of requested braking pressure for a prescribed amount of time. The metering device can be an inversion valve and orificed check valve in a control circuit adapted to allow relatively unrestricted flow until a threshold pressure is reached, after which pressure the inversion valve closes and the flow is metered through an orifice. This has the effect of allowing rapid brake actuation to a first level, and then slowing further application of the brake until full requested braking is achieved. An electronic control unit can also be configured to regulate a control signal to delay development of the requested brake pressure.

In some aspects, a master cylinder assembly for vertical lift aircraft is configured to move pressurized fluid through a conduit in response to applied movement of an input lever. A low pressure relief valve can be connected to a first conduit to limit pressure to a low level. An isolation valve can be connected to the first conduit and configured to isolate the low pressure relief valve from the conduit when engaged. A high pressure relief valve can be connected to a second fluid conduit to limit pressure to a high level. In some aspects, a rotor brake actuator is fluidly connected to the first conduit and the second conduit and configured to engage a rotor brake in response to hydraulic fluid pressure.

A brake control system for motor vehicles includes a stability system for stabilizing the vehicle from the standpoint of driving dynamics during braking, a triggering unit for the automatic output of a braking demand as a function of the traffic situation, a braking unit which converts the braking demand into a braking action, and a control unit for modifying the braking demand prior to its implementation as a function of the state of the stability system.

Methods and systems for a go/no-go Landing Decision Point (LDP) are disclosed. The methods and systems provide a graphical LDP on a cockpit display that pilots can use to determine whether to continue the landing or execute a go-around. The methods and systems may be implemented in embodiments having an onboard portion, an off-board portion, or both operatively coupled to provide an LDP in a preview/planning mode and real time mode.

A brake fade determination device determines whether a fade state of a brake device that brakes a wheel of a vehicle is occurring on the basis of the deceleration of the vehicle and the slip amount of the wheel. A braking system includes: the brake device that is able to adjust a braking force that acts on the wheel of the vehicle; and a controller that controls the braking force to control the slip condition of the wheel. The controller determines whether a fade state of the brake device is occurring on the basis of the deceleration of the vehicle and the slip amount of the wheel, and adjusts the amount of increase or decrease in braking force on the basis of whether the fade state is occurring.

A pressure control reservoir includes a valve ball and a shaft which is movable to move the valve ball to open or close a fluid path leading to a fluid reservoir chamber. The shaft has a tip with a slant surface which has a peripheral edge of a polygonal shape with even numbers of vertices and is inclined to the longitudinal center line of the shaft. Such a polygonal geometry increases an entire or inclined length of the slant surface, which results in an increased range where an angle which the slant surface makes with a plane extending perpendicular to an axial direction of the tip is permitted to be increased without causing the point of contact between the valve ball and the slant surface to be shifted close to the tip of the slant surface when the tip of the shaft moves the valve ball.

A vehicle brake system includes a brake pedal unit (BPU) coupled to a vehicle brake pedal and including an input piston connected to operate a pedal simulator during a normal braking mode, and coupled to actuate a pair of output pistons during a manual push through mode. The output pistons are operable to generate brake actuating pressure at first and second outputs of the BPU. A hydraulic pressure source for supplying fluid at a controlled boost pressure is included. The system further includes a hydraulic control unit (HCU) adapted to be hydraulically connected to the BPU and the hydraulic pressure source, the HCU including a slip control valve arrangement, and a switching base brake valve arrangement for switching the brake system between the normal braking mode wherein boost pressure from the pressure source is supplied to first and second vehicle brakes, and the manual push through mode wherein brake actuating pressure from the BPU is supplied to the first and second vehicle brakes.

When a trailer is pulled by a tow vehicle where the trailer begins to sway to the left and right of the tow vehicle a large sway can result in loss of control of the trailer and or tow vehicle. The field of the present invention is a system and method of controlling a trailer sway which comprises determining the sway of the trailer utilizing an electronic sensor and independently applying the left and or right trailer brakes at varying levels to reduce trailer sway the traditional single braking signal power from the tow vehicle is separated into two independent braking signals for each of the left and right brakes. All brakes are applied whenever the traditional braking signal goes active where trailer battery power is utilized to independently activate the left and or right brakes during trailer sway.

Provided is a braking control system including: an internal combustion engine serving as a power source of a vehicle; a brake servo unit operated by a negative pressure supplied thereto; a passage configured to supply an intake negative pressure of the internal combustion engine to the brake servo unit; and a negative pressure pump configured to generate a negative pressure by being driven by power transmitted from a wheel of the vehicle and transmit the generated negative pressure to the brake servo unit, wherein the negative pressure pump is driven so as to supply the negative pressure to the brake servo unit during execution of inertia running in which the internal combustion engine stops and the vehicle runs by inertia.

A system for electrical braking of a vehicle comprises a power bus coupled to a first driver associated with a first electromechanical actuator (EMA). The power bus is also coupled to a second driver associated with a second EMA, and the first EMA and the second EMA are associated with a wheel of the vehicle. The power bus provides braking power to the first EMA via the first driver and to the second EMA via the second driver. A normal braking command interface provides a first braking signal to the first driver and a second braking signal to the second driver. An emergency/park brake interface bypasses the normal braking command interface and sends a first emergency/park braking signal to the first driver and a second emergency/park braking signal to the second driver. A sensor measures a current at a single location of the power bus that is proportional to a braking force exerted on the wheel.

Disclosed is a method for operating an electromechanically operable parking brake for motor vehicles with a driving engine furnished with a mechanical gear box, being substantially composed of an operating element, an electronic control unit, to which are sent wheel rotational speed values from wheel rotational speed sensors, at least one unit for generating a brake application force, and brake devices on at least one axle being lockable by the unit, with the electronic control unit actuating the unit after detection of a starting maneuver of the motor vehicle in the sense of a release operation of the parking brake. In order to render a release operation of the parking brake as comfortable as possible after detection of a starting maneuver of the motor vehicle, the method at issued arranges that the electronic control unit (6) actuates the unit (1) in order to reduce the brake application force to an inclination-responsive holding force when a starting maneuver is detected and before the release operation of the parking brake is performed.

An electric driving type utility vehicle having a regenerative brake force distribution control function, and a regenerative brake force distribution control method thereof are provided. The utility vehicle includes: a controller for controlling an output and a recovery of a motor; recovery sensing means for sensing a recovery braking state when the motor is driven; a power measurement unit for measuring the amount of recovery power generated in the recovery braking state; and a power switching unit for automatically switching a drive mode from a two-wheel drive mode to a four-wheel drive mode or vice versa according to the load condition. The present invention can switch the present mode to the four-wheel drive mode by operating the power switching unit according to the control of the controller when sensing the recovery brake through the recovery sensing means in the driving state.

A control device for a braking system of a vehicle is provided, having a first receiving device which receives a provided brake activation intensity variable, a plunger control device which determines a setpoint fill level variable of a plunger, taking into account at least the received brake activation intensity variable, and a corresponding plunger control signal is outputtable so that a ratio of an actual volume and a maximum fillable volume of a storage volume of the plunger is settable corresponding to the determined setpoint fill level variable. For a brake activation intensity variable corresponding to a predefined non-activation intensity variable, the plunger control device determines a fill level variable different from an empty state as the setpoint fill level variable, and outputs a plunger control signal corresponding to the determined setpoint fill level variable to the plunger such that the plunger is at least partially filled.

A brake control device for a brake system. The control device can perform both an interlocking brake control and an antilock brake control. The brake system includes a front-wheel hydraulic circuit, a front-wheel-side braking part; a rear-wheel hydraulic circuit, a rear-wheel-side braking part; and an electrically-operated pump which pressurizes the brake fluid. The brake control device includes a usual voltage mode where the interlocking brake control or the anti-lock brake control is performed when the supply voltage is a first voltage or more, and a low voltage mode where at least one of the interlocking brake control and the anti-lock brake control is performed in a limited manner when the supplied voltage is a second, lower voltage. An operation mode is changed from the usual voltage mode to the low voltage mode when it is determined that the supply voltage becomes lower than the first voltage.

Disclosed is a control method of an electronic parking brake system, which variably controls the duty of voltage applied to a motor upon release of the electronic parking brake system. The control method includes controlling voltage applied to a motor to a first duty ratio upon release of the electronic parking brake system, controlling the voltage applied to the motor to a second duty ratio greater than the first duty ratio if locking of the motor occurs and the motor is not operated, and controlling the voltage applied to the motor to the first duty ratio if locking of the motor is released and the motor begins to operate, after the control of voltage to the second duty ratio.

A pressure control valve arrangement for controlling a fluid pressure in an ABS brake system of a vehicle so that, while there is a tendency of individual wheels of the vehicle to lock, the brake pressure in at least one associated brake cylinder can be adaptively adjusted, including: a housing; and at least one diaphragm valve is accommodated in the housing, the diaphragm valve having a diaphragm as the valve body, which diaphragm can be acted upon by introducing pressure medium into a control chamber that is covered on the outside of the housing by a cover so that the control chamber is formed between the diaphragm and the cover, wherein at least one pressure medium channel carrying pressure medium is formed in the housing in the region of the cover, wherein at least one cover has at least one projection projecting into the pressure medium channel in the housing, a pressure medium guiding surface for directing the flow of the pressure medium carried in the pressure medium channel being formed on the projection.

A flat, box-shaped hydraulic block for the mechanical fastening and hydraulic interconnection of solenoid valves, pump elements, etc. of a slip-controlled vehicle brake system connects connections of installation spaces for the pump elements to connectors for a brake master cylinder and connections of receptacles for pressure build-up valves which run past one another via flat chambers on longitudinal sides of the hydraulic block and short blind bores. As a result, the receptacles of the pressure build-up valves are connected to the connectors for the brake master cylinder. The chambers damp pressure pulses of the pump elements of a piston pump.

A method of controlling a vehicle having a transmission system, an engine system, and a braking system includes detecting a braking condition of the braking system. The braking condition is at least one of a brake temperature being above a predetermined brake temperature limit and a braking load being above a predetermined braking load limit. The method also includes detecting a second condition of at least one of the transmission system and the engine system. The method also includes determining whether the second condition satisfies predetermined criteria. Furthermore, the method includes detecting an absolute vehicle acceleration that is below a predetermined acceleration limit. Moreover, the method includes downshifting from a current gear to a lower gear to thereby cause engine braking when the braking condition is satisfied, the second condition satisfies the predetermined criteria, and the absolute vehicle acceleration is below the predetermined acceleration limit.

A vehicle yaw stability control method and a vehicle yaw stability control apparatus are provided. The yaw rate {dot over (ψ)} of the vehicle is measured. A first reference yaw rate {dot over (ψ)}ref is set. A difference yaw rate Δ{dot over (ψ)} is set. Stabilizing braking intervention is triggered when a value of the difference yaw rate Δ{dot over (ψ)} exceeds limits defined by difference yaw rate threshold values Δ{dot over (ψ)}min, Δ{dot over (ψ)}max. Information regarding the shape of the road ahead of the vehicle is acquired. The reliability of the driver steering input δ is evaluated upon stabilizing braking intervention being triggered. In case the driver steering input δ is deemed unreliable a replacement reference yaw rate {dot over (ψ)}refroad is set based on the acquired road shape and a replacement difference yaw rate Δ{dot over (ψ)}road is set whereupon stabilizing braking intervention is performed based on the replacement difference yaw rate Δ{dot over (ψ)}road.

A method and a device for controlling and/or regulating an electric motor. Such electric motors are used for example in motor vehicles in the form of pump motors. In general, the electric motor is supplied with electrical energy from a battery and/or using a generator. The controlling and regulation take place using a high-frequency pulse width modulation (PWM). When the electric motor is started, the PWM is used to continuously increase the motor current required for the operation of the electric motor, e.g. beginning from 0.

A variable speed power converter controls the speed of a load in a material handling system as a function of the torque required to move the load. While the power converter is running, the torque being produced in the motor is determined. The power converter then determines the maximum rotational speed of the motor as a function of the torque currently being produced and of the torque-speed curve of the motor. The power converter then commands the motor to rotate at this maximum rotational speed. The power converter periodically monitors the torque being produced and adjusts the maximum rotational speed of the motor throughout the run.

A motor control device comprises: an acceleration upper limit estimating unit; a target acceleration setting unit; a motor control unit; and a deficit calculating unit, wherein the target acceleration setting unit corrects the target acceleration based on the acceleration profile by an amount corresponding to the acceleration deficit within a range in which the target acceleration does not exceed the acceleration upper limit on the basis of the acceleration deficit calculated by the deficit calculating unit to set the target acceleration at each time.

To achieve peak acoustic and power performance, the coil or applied current should be in phase or substantially aligned with the back electromotive force (back-EMF) voltage. However, there are generally phase differences between the applied current and back-EMF voltage that are induced by the impedance of the brushless DC motor (which can vary based on conditions, such as temperature and motor speed). Traditionally, compensation for these phase differences was provided manually and on an as-needed basis. Here, however, a system and method are provided that automatically perform a commutation advance by incrementally adjusting a drive signal over successive commutation cycles when the applied current and back-EMF voltage are misaligned.

A motor control apparatus for controlling a DC motor includes a first detection unit configured to detect an angular velocity of the DC motor, a driven member configured to be driven by the DC motor, a control unit configured to perform, during start-up of the DC motor, feed forward control for changing a control value used for controlling drive of the DC motor from a first control value corresponding to an angular velocity smaller than a target angular velocity to a second control value corresponding to the target angular velocity, and to change the feed forward control to feedback control for controlling the control value based on a detection result by the first detection unit to keep the DC motor at the target angular velocity, and a second detection unit configured to detect whether the driven member has been replaced.

An electric motor, having a stator (465), a rotor (470), and an apparatus for evaluating a signal provided for controlling said motor (110), comprises a receiving unit (430, 440) for receiving a control signal (PWM_mod), which is a pulse width modulated signal (PWM) onto which a data signal (DIR, DATA) is modulated. An evaluation unit (440) is provided for evaluating the modulated control signal (PWM_mod). The unit is configured to extract, from the modulated control signal (PWM_mod), data provided for operation of the motor (110). The control apparatus includes a signal generator (450) configured to generate, on the basis of the extracted or ascertained data provided for operation of the motor (110), at least one control signal for the motor (110), such as a commanded direction of rotation. Piggybacking other control data onto the PWM power level signal reduces hardware investment, by permitting omission of a signal lead which would otherwise be required in the motor structure.

Electromotive furniture-flap drive, characterized by an identification device for automatically identifying the type of furniture flap in the installed state of the furniture flap drive.

A system and method for determining the start position of a motor. According to an embodiment, a voltage pulse signal may be generated across a pair of windings in a motor. A current response signal will be generated and based upon the position of the motor, the response signal will be greater in one pulse signal polarity as opposed to an opposite pulse signal polarity. The response signal may be compared for s specific duration of time or until a specific integration threshold has been reached. Further, the response signal may be converted into a digital signal such that a sigma-delta circuit may smooth out glitches more easily. In this manner, the position of the motor may be determined to within 60 electrical degrees during a startup.

A control circuit for a blender provides low-cost power conditioning through the use of a high resistance which provides temporary power for operation of low-voltage logic circuitry and low-voltage switches for a time sufficient to switch the motor on, and a lower resistance which provides sufficient power for maintaining the motor on state indefinitely as instructed by the low-voltage logic circuitry. Low average power dissipation is provided by powering the low-voltage logic circuitry and low-voltage switches using the high resistance in a standby mode and switching in the lower resistance only when the motor is activated.

A circuit for speed monitoring of an electric motor comprises a circuit for generating a time-frame signal, a circuit for receiving a first signal from a chopper driver circuit designed to drive the electric motor, a circuit for detecting chopper pulses in the first signal, a pulse counter, and a circuit for at least one of outputting and evaluating a state of the pulse counter, after the inactive state of the time-frame has been indicated. The time-frame signal indicates when a time-frame of predefined length changes from an inactive state to an active state and indicates when the time-frame changes back from the active state to the inactive state. The pulse counter is designed to count the detected chopper pulses while the active state is indicated by the circuit for generating the time-frame signal.

A method and device for controlling an electric motor, in particular a machine tool drive, wherein during a sensorless open-loop control mode of operation of the electric motor the speed and the torque are determined from the motor current and the motor voltage, and the moment of inertia of the electric motor torque are determined from the determined motor current and the determined motor voltage, wherefrom then a control torque is determined, which is then associated with an open-loop torque control value and supplied as the torque setpoint value to a control element for setting the motor current and/or the motor voltage in the open-loop mode of operation. As long as the speed is below a minimum speed, the control element receives as input variable a control or pilot control torque generated from a predefined moment of inertia for a sensorless closed-loop control mode of operation of the electric motor.