Abstract: An electric power tool is provided that includes a motor as a driving source, a first operation switch, a first semiconductor switch, and a second semiconductor switch. The first operation switch is operated by a user to be turned ON/OFF. The first semiconductor switch, provided on a current path from the power source to the motor, includes at least one semiconductor switching device. When the first operation switch is OFF, the first semiconductor switch is turned OFF to interrupt the current path. When the first operation switch is ON, the first semiconductor switch is turned ON to close the current path. The second semiconductor switch is provided on the current path in series with the first semiconductor switch and includes at least one semiconductor switching device. The second semiconductor switch closes/interrupts the current path by being turned ON/OFF in accordance with an input control signal.

Abstract: A system for controlling a disk in a disk drive includes a motor control circuit and a first circuit that retrieves firmware speed control instructions from non-volatile memory. During retrieval of the firmware speed control instructions, at least one of the motor control circuit determines a position of the disk, one of the first circuit and the motor control circuit spins up the disk and the motor control circuit ramps up a speed of the disk. The first circuit performs speed control of the disk based on the firmware speed control instructions.

Abstract: Information indicative of the placement of spindle motor components may be obtained and used to provide a correction to one or more BEMF-derived attributes used to control the spindle speed. In some implementations, first and second signals indicative of BEMF of different stator windings may be used to determine a speed-related characteristic. The speed related characteristic may be used to determine an error amount, which may be used to determine a correction factor to control the speed of the spindle motor.

Abstract: A phase difference detection device able to detect a phase with a high precision is provided.

Abstract: A speed controller used in a control loop of a motor includes a comparator, a processing device, and an arithmetic logical unit (ALU). The comparator compares a received instruction speed or a received measured speed of the motor with a predetermined speed value, outputs a first signal to the processing device when the received speed is greater than the predetermined speed value, or outputs a second signal to the processing device when the received speed is equal to or less than the predetermined speed value. The processing device receives a speed difference between the instruction speed and the measured speed. The processing device outputs a first proportional value when the first signal is received, or outputs a second proportional value when the second signal is received. The ALU outputs an instruction current to the control loop by calculating the proportional value according to a predetermined calculation rule.

Abstract: The present invention relates to a circuit for detecting a functional status of an electro-motor. Typical electro-motors need additional components to identify the functional status of the motor. This means additional weight for such motors determining the functional status. According to the present invention a circuit is provided using a part of a motor as a sensor for detecting the functional status of the electro-motor.

Abstract: The model train control system includes a remote control device that receives user input with respect to various train functions such as desired speed and effects, and that generates commands based on that input in order to cause the model train to perform in a desired manner. In an embodiment of the invention, the model train controller comprises control input devices that permit user control over corresponding control features of the model train. A touch screen display may be coupled to the housing and adapted to receive user selections regarding the control features. A processor is operatively coupled to the control input devices and the touch screen display. The processor is adapted to generate at least one model train command to be transmitted to the model train based at least in part on a user input received from either one of the control input devices or the touch screen display.

Abstract: An electric bike includes a wheel driving apparatus. The wheel driving apparatus includes an electric wheel drive motor which drives a wheel, a gap changer which changes a gap length in the wheel drive motor, and a motor control unit which controls the wheel drive motor and the gap changer. The motor control unit calculates a target gap length for the gap changing motor in the gap changer based on an accelerator opening-degree signal, a rotation speed, a q-axis electric-current command value, a power source voltage, and a voltage utilization rate. Then, a feedback control is provided to the gap changer based on a difference value between the target gap length and the actual gap-length. A good vehicle characteristic is obtained without being affected by individual variability or operating environment of the electric motor through efficient drive of the electric motor from a low-speed range through a high-speed range.

Abstract: The present invention relates to a method for ensuring a constant target speed of a battery driven electrical motor, the battery driven electrical motor being adapted to move a piston rod in an injection device so as to inject a set dose of medicine from the injection device, the method comprising the steps of setting a first target speed to be reached by the motor, determining whether the first target speed can be reached, and, if the first target speed can be reached, maintaining the first target speed until a set dose of medicine has been injected from the injection device, or if the first target speed cannot been reached, setting a second target speed.

Abstract: The present invention relates to a method and a circuit of controlling a speed of a brushless motor of a ceiling fan. The circuit includes a motor PWM duty consumption sampling unit and a motor speed sampling to sense a PWM duty and a speed of the brushless motor. A central processing unit is provided to compare the PWM duty and the speed of the brushless motor to a preset maximum PWM duty and a preset maximum speed. When the PWM duty reaches to the preset maximum PWM duty first, the central processing unit sets the current speed to be a maximum speed, and speeds of each level are calculated according to the maximum speed. If the speed reaches to the preset maximum speed first, a constant-speed control will take over to control the brushless motor, and speeds of each level are according to the preset speeds.

Abstract: A starting method and system for a motor where the motor may be started as an induction motor by applying a magnetizing current to build flux through the stator, with the field current set at the maximum permissible exciter stator current (i.e., the current that will cause rated no-load current in the main field at the transition speed). The motor stator currents will be maintained at a value that allows the motor to generate sufficient breakaway torque to overcome any stiction. At a specific transition speed or after a period of time, the drive will initiate a transition from induction motor control to synchronous motor control by removing the initial magnetizing current, and a field current is then applied to the motor through the DC exciter. Once this transition is completed, the drive may ramp up to the desired speed demand.

Abstract: A man-machine interface which provides tactile feedback to various sensing body parts is disclosed. The device employs one or more vibrotactile units, where each unit comprises a mass and a mass-moving actuator. As the mass is accelerated by the mass-moving actuator, the entire vibrotactile unit vibrates. Thus, the vibrotactile unit transmits a vibratory stimulus to the sensing body part to which it is affixed. The vibrotactile unit may be used in conjunction with a spatial placement sensing device which measures the spatial placement of a measured body part. A computing device uses the spatial placement of the measured body part to determine the desired vibratory stimulus to be provided by the vibrotactile unit. In this manner, the computing device may control the level of vibratory feedback perceived by the corresponding sensing body part in response to the motion of the measured body part. The sensing body part and the measured body part may be separate or the same body part.

Abstract: A rotor position detecting circuit includes a first position detecting circuit having a low-pass filter that shapes up phase voltage induced in a phase coil and a first comparator that compares the output voltage of the low-pass filter with a threshold level to form a first rotor position signal, and a second position detecting circuit having a second comparator that compares the phase voltage with a threshold voltage and a control unit that digitally processes the output voltage of the second comparator to form a second rotor position signal. The control unit corrects the first rotor position signal by the second rotor position signal to provide a final rotor position signal when the rotation speed of the brushless DC motor is in a measurable range.

Abstract: The invention concerns an electronic module for a motor vehicle, in particular a fan regulator (4?) with a control input (S) for a signal, in particular a pulse width modulated signal, transmitted via a signal line (3). The electronic module is designed for the generation of an essentially constant potential (Ubias, Ubias?UBE) at the control input (S), which preferably is designed as a current-controlled, low resistance control input. The invention also concerns an arrangement (1?) for the transmission of a preferably pulse width modulated signal with: a control device (2?) for the generation of the signal, a signal line for the transmission of the signal, and an electronic module as described above.

Abstract: A system comprising a chassis that includes a plurality of modules and a fan assembly disposed in a distal end of the chassis for drawing air in parallel pathways through the plurality of modules. At least one of the modules is a compute module having a thermal sensor disposed to sense the temperature of air flowing across a processor mounted on a motherboard. The system further comprises a fan controller receiving output from the thermal sensor, wherein the fan controller operates the fan assembly to cool the plurality of modules and maintain the thermal sensor output within an operating temperature range. The fan controller controls the fan speed according to predetermined thermal profile settings associated with one of the compute modules received in the chassis. For example, the predetermined thermal profile settings may include a minimum fan speed, a maximum fan speed, and control loop feedback settings.

Abstract: Windshield wiper device (10), particularly for a motor vehicle, having at least an electric motor drive (24) is proposed. This comprises an electric motor drive, which can be driven with at least one first speed (V1) and one second speed (V2). According to the invention, a temperature detection means (40) for detecting the operating temperature of the drive (24) and at least one switching means (50) are provided, which, when operating the drive (24) at the second speed (V2), switches the drive (24) from the second speed (V2) to the first speed (V1) when a predetermined operating temperature (T1) is exceeded.

Abstract: A motor speed control system includes a pulse outputting device capable of outputting a pulse each time a motor rotates, a pulse interval determining device capable of determining a pulse interval between the pulses outputted, and a comparative value calculating device capable of obtaining a comparative value as the product of a first value and a second value. The first value can correspond to the pulse interval determined, and the second value can correspond to a set rotational speed of the motor. The system can further include a set value calculating device capable of obtaining a set value as the product of the second value and a third value and a controller capable of controlling a supply of power to the motor such that a difference between the set value and the comparative value decreases.

Abstract: A circuit for controlling a rotation speed of a computer fan includes a control chip, a conversion circuit, a fan header, a first switch, and a second switch. When a first terminal of the first switch is connected to a second terminal of the first switch, and a first terminal of the second switch is connected to a second terminal of the second switch, the conversion circuit converts a control signal received from the control chip to a voltage signal, and outputs the voltage signal to a power pin of the fan header. When the first terminal of the first switch is connected to a third terminal of the first switch, and the first terminal of the second switch is connected to a third terminal of the second switch, a control pin of the fan header receives the control signal, the power pin receives power from a first power supply.

Abstract: When an ECU receives a transmission signal having a high level from a transmission, the ECU exerts torque reduction control to reduce a torque control value for a motor generator. Furthermore the ECU sets an optimum (or target) value of a voltage as based on the torque control value and a motor rotation speed and controls an upconverter. Herein, when the transmission is shifting gears, the ECU controls the upconverter to allow the voltage to be constant regardless of whether the torque reduction control is exerted to reduce the torque control value.

Abstract: A fan system includes a connecting device, a controlling device and a fan device. The connecting device includes a first pin receiving at least one driving signal, and a second pin receiving a start signal, wherein a length of the first pin is greater than a length of the second pin. The controlling device is electrically connected with the connecting device and includes an enabling unit. The enabling unit generates at least one first enabling signal according to the start signal, and the controlling device outputs the driving signal and the first enabling signal. The fan device is electrically connected with the controlling device and includes at least one fan. The fan device transmits the driving signal to the fan and drives the fan according to the first enabling signal.

Abstract: If a PWM duty instruction D1 determined by a duty calculation circuit exceeds an upper limit value, a duty signal processing circuit in a motor drive apparatus divides a switching current supply period in each of the phases into a first current supply period and a second current supply period. In the first current supply period, the duty is set to the upper limit value. In the second current supply period, the duty is set to 100%, and the length of the second current supply period is set depending upon the duty instruction.

Abstract: The seat which is provided with at least two elements which can be moved relative to each other and an actuator for maneuvering a movable element, a unit for controlling the actuator for the movement of the movable element comprises: means for measuring a force (Cu) applied manually to the movable element by a user, the control unit comprises: means for calculating the theoretical force (Cth) which must be applied by the actuator to the movable element in the direction of the force (Cu) applied manually to the movable element by the user; and means for controlling the actuator for the movement of the movable element in accordance with the theoretical force (Cth).

Abstract: This invention relates to a method of speed control selection for an electronically commutated motor comprising the following steps: (a) a motor controller receives an input signal T from a speed control selection circuit; (b) the motor controller retrieves a corresponding value for a motor running speed S from a comparison list correlating the input signal with the motor running speed, which list has been stored in the motor controller in advance, by searching the comparison list for the input signal T; and (c) the motor controller controlling a motor M to run at the motor running speed S, achieving the purpose of the speed selection. This method allows for from 2 to 256 speed choices with a single signal wire only. Such a circuit structure has the advantages of high integration, simple wiring, low cost, good performances, low failure rate, higher number of optional speeds, and simpler and more practical control.

Abstract: A control and motor arrangement in accordance with the present invention includes a motor configured to generate a locomotive force for propelling the model train. The control and motor arrangement further includes a command control interface configured to receive commands from a command control unit wherein the commands correspond to a desired speed. The control and motor arrangement still further includes a plurality of detectors configured to detect speed information of the motor, and a process control arrangement configured to receive the speed information from the sensors. The process control arrangement is further configured and arranged to generate a plurality of motor control signals based on the speed information for controlling the speed of said motor. The control and motor arrangement yet still further includes a motor control arrangement configured to cause power to be applied to the motor at different times in response to the motor control signals.

Abstract: Control over velocity of a model train may be determined based upon the speed of rotation of a control knob. A processor receives electronic pulses indicating rotation of the knob beyond a predetermined increment of angular distance. The processor calculates the amount of power ultimately conveyed to the model train based not only upon the number of pulses received, but also upon the elapsed time between these pulses. The shorter the elapsed time between pulses, the greater the change in power communicated to the train. Initially, a user can rapidly rotate the knob to attain coarse control over a wide range of velocities, and then rotate the knob more slowly to achieve fine-grained control over the coarse velocity. Utilizing the control scheme in accordance with embodiments of the present invention, in a compact and uninterrupted physical motion, a user can rapidly exercise both coarse and fine control over velocity of a model train.

Abstract: A system can control a rotary speed of a computer fan according to the type of the computer fan. If the computer fan is determined to be a 3-pin fan, the system can output a changeable voltage to control the rotary speed of the 3-pin fan.

Abstract: A fan speed control system for a machine is disclosed. The control system may include a fan to provide a flow of coolant to the machine. The system may further include a first sensor configured to generate a first signal indicative of an operational parameter of the machine, a second sensor associated with the fan to generate a second signal indicative of an actual speed of the fan, and a controller communicatively coupled to the fan, the first sensor, and the second sensor. The controller may be configured to generate a third signal indicative of a desired fan speed based on the first signal, and a fourth signal indicative of a difference between the desired fan speed and the actual fan speed. The controller may drive the fan based on the third signal and the fourth signal.

Abstract: A fan driver circuit for powering a fan with a linear voltage may be designed using digital design techniques, resulting in a testable, accurate circuit on a smaller die size. The fan driver circuit may be configured to receive a digital control signal, which may be a sequence of numeric values, e.g. multiple-bit binary numbers, each indicative of a desired present rotational speed of the fan. The fan driver circuit may be implemented using a digital modulator, e.g. a delta-sigma modulator, with a simple low-pass filter, e.g. an RC-filter at the output, and may use oversampling based on a system clock, to shift in-band noise to out-of-band frequencies, and digital interpolation to filter out unwanted images from the upsampled digital control signal. The delta-sigma modulator may be constructed as a first-order delta-sigma modulator using an error-feedback structure to reduce die size.

Abstract: A PLL for controlling a motor includes first and second feedback loops. The first feedback loop includes an oscillator for generating a signal having a frequency corresponding to an input voltage, a first phase comparator for outputting a first phase difference signal corresponding to a phase difference between the signal from the oscillator and an input signal, and a first smoothing filter for smoothing the first phase difference signal to output the smoothed signal as the input voltage. The second feedback loop includes a second phase comparator for outputting a second phase difference signal corresponding to a phase difference between a signal having a frequency corresponding to a rotational speed of the motor and the input signal, an adder for adding the first and second phase difference signals, and a second smoothing filter for smoothing an output of the adder to output the smoothed signal to the motor.

Abstract: A motor control method includes the steps of: measuring a time period from an output of a drive detection signal to a next output of a drive detection signal; storing the measurement result at each time of output of a drive detection signal as a measured cycle; calculating a driven velocity of the driven object based on the stored measured cycle; calculating an operation amount of the motor such that the calculated driven velocity is equal to a predetermined target velocity. In the motor control method, it is determined, at each calculation timing, whether or not the driven object is in a low velocity state where an actual velocity is lower than the target velocity. When determined affirmative, calculation of the driven velocity of the driven object is performed based on a measured value being currently measured at the calculation timing in place of the stored measured cycle.

Abstract: A method of controlling in-rush current to a DC motor is disclosed. The method may include operating the DC motor in a first mode including applying back-EMF across a relay coil to maintain the relay in an open configuration when the back-EMF is below a predetermined voltage. The method may also include operating the DC motor in a second mode including applying the back-EMF across the relay coil to maintain the relay in a closed configuration when the back-EMF is equal to or above the predetermined voltage.

Abstract: A heat dissipation system for an electronic device comprises a base, a fan, a pulse width modulation speed control circuit controlling the speed of the fan, a converter outputting a voltage signal, a selection switch connected to the motor, and a control element provided on the base, connected to the switch and to the converter. When the control element is operated, the switch selectively enables the motor be connected to the output of the pulse width modulation speed control circuit or to the output of the converter, and when the motor is electrically connected to the converter, the control element can modify the output voltage of the converter.

Abstract: A motor drive circuit includes: a pulse generation circuit configured to generate a pulse signal whose duty ratio of one logic level is increased as a drive voltage is increased in accordance with a target rotation speed of a motor; and a drive control circuit that configured to drive the motor with the drive voltage using a duty ratio higher than the duty ratio of the pulse signal when the motor starts rotating from the stopped state, and configured to drive the motor with the drive voltage during a period when the pulse signal is at the one logic level after the motor starts rotating, based on a rotation signal corresponding to the rotation of the motor.

Abstract: A protecting device of a fan system includes at least one first switch element and at least one control unit. The first switch element receives a first input signal. The control unit is electrically connected with the first switch element, receives the first input signal, and controls the first switch element to turn on or turn off according to the first input signal. The control unit stops outputting the first input signal when the first switch element turns on. The control unit outputs the first input signal when the first switch element turns off, so that a fan of the fan system can be driven by the first input signal.

Abstract: A supply current control circuit controls the voltage of a low-voltage direct-current power source so that the average current of an inverter circuit detected by a current detecting circuit becomes constant at a specified current value. Accordingly, characteristics that are little in the amount of change of air volume are obtained.

Abstract: A heat dissipation system includes at least one fan, at least two controllers, a signal generator, and a signal converter. The controllers are electrically connected to the fan and generate an enable signal according to a feedback signal of the fan. The signal generator is electrically connected to the controllers and generates a control signal according to the enable signal. The signal converter is electrically connected to the signal generator and the fan, converts the control signal to a drive signal to the fan, thereby controlling rotation speed of the fan.

Abstract: A valve timing controller has the drive circuit which performs a feedback control of the energization to the electric motor based on the target rotation speed and the actual rotation speed of the electric motor, and rotates the electric motor to the target rotation direction. An invalid switch part of the drive circuit suspends the feedback control at the time of change of the target rotation direction.

Abstract: The invention relates to a device and a method for estimating the rotational speed ? of an electric motor when freewheeling, the method being carried out in a variable speed drive for controlling the motor by generating reference alternating voltages Va, Vb. The method comprises a step for measuring the measured flux and torque currents Id and Iq of the motor in an orthogonal two-phase marker d, q, a step for determining said reference voltages Va, Vb, by carrying out a current regulation on the basis of said measured currents, and on the basis of zero reference currents Idref and Iqref in said marker d, q, and a step for calculating the rotational speed ? by evaluating the angle of rotation of the voltage vector, the components of which are said voltages Va, Vb in a fixed orthogonal two-phase marker a, b.

Abstract: A drive control assembly for a motor including a variable frequency drive module for providing variable speed control for the motor, a bypass module for providing bypass control for the motor, and a switch for switching control for the motor between the variable frequency drive module and the bypass module. The bypass module can provide control for the motor even when the variable frequency drive module is removed from the drive control assembly.

Abstract: In a speed control device including a speed instruction generating unit, an addition computing unit, a speed control unit, a current controlling unit, an inertia estimating unit, an inertia setting unit, a switching unit and a constant setting unit, when it is possible to perform accelerating or decelerating operation of the electric motor to estimate the inertia moments of the electric motor and a driving target thereof, an operation is carried out to derive an inertia moment estimation value. The proportional gain of the speed control unit is set through the switching unit and the constant setting unit on the basis of the inertia moment estimation value. When it is impossible to perform the above operation, the proportional gain of the speed control unit is set through the switching unit and the constant setting unit on the basis of the inertia moment manual set value.

Abstract: The invention relates to a method and a circuit for regulating the speed of a commutator series-wound motor, especially a universal motor (10), which is supplied with a current from an a.c. voltage source (22) by means of a semiconductor switching element (18) mounted in series with an armature winding (12) and a field winding (14, 16) and controlled by a control unit (28) according to a nominal speed value. The control unit (28) receives, as input signals, signals corresponding to the total voltage drop (Umot) when the motor (10) is supplied with a current, and a substitute signal for the intensity of the motor current (I), corresponding to the voltage drop (Ua, Ufa) on the armature (12) alone or on the armature (12) and on a part (14) of the field winding (14, 16).

Abstract: An adjustable frequency pump control system (10) that is primarily designed for use in commercial pool filtration systems. The system (10) automatically selects one of three operating speeds that control the speed of a motor that operates a circulation pump (62). The system (10) includes a programmed logic control (PLC) (42) that is activated upon the application of select mode signal (31), a mode timing signal (35), a line pressure signal (37), a circulation pump-run signal (39) and a backwash signal (41). The output of the PLC (42) is a frequency set signal (17) that is applied to an adjustable frequency drive (AFD) (18). From the output of the AFD (18) a motor speed control signal is produced that is applied to the motor that operates the circulation pump (62). The speed of the circulation pump (12) is governed by the frequency of the motor speed control signal, wherein the frequency is determined by the motor speed that is applicable to a particular design point of the pump's filtration cycle.

Abstract: A circuit for controlling rotation speed of a computer fan includes a fan connector providing for controlling the rotation speed of the computer fan, a rotation speed detector providing for detecting the rotation speed of the computer fan, a BIOS chip connected to the fan connector via the rotation speed detector and provided for receiving, and comparing rotation speed signals from the rotation speed detector, a super I/O chip connected to the BIOS chip and provided for outputting either a PWM signal or another PWM signal to be converted to a voltage signal to control rotation speed of the computer fan according to the result of the comparison, a integrated circuit connected to the super I/O chip and the fan connector and configured for converting the another PWM signal to an analog voltage signal.

Abstract: A rotor position detection circuit detects a position of a rotor in a motor from a detection signal of an induced voltage generated in a stator coil. The circuit includes: a first low pass filter having a first reference potential for filtering the detection signal; a comparator for comparing an output signal from the first low pass filter with a predetermined reference voltage and for outputting a rotation position signal; and a second low pass filter having a second reference potential for filtering a virtual neutral point potential of the motor. The first reference potential is the filtered virtual neutral point potential, and the second reference potential is a ground.

Abstract: When controlling an air compressor (13) for a pneumatic braking system on a large hybrid commercial vehicle (e.g., a bus, a package delivery truck, etc.), PID control of an air compressor motor (12) is employed during normal system operation such as when the motor shaft is spinning, and state machine control is employed during startup or upon a system disturbance such as a shaft seizure or stall. In this manner, stalling events that occurs due to PID control inability to correct for unexpected disturbances are mitigated by employing state machine control.

Abstract: The invention relates to a series resistor assembly (1) for an electric motor (M), in particular for an electrically driven ventilating fan in a vehicle. Said assembly comprises a series resistor (2) for controlling the RPM of the electric motor (M) in one or more RPM stages (ST1, ST2, to STn) and a thermal link (6) that is optionally connected in series to the series resistor, a reversible switching element (4) for at least one of the RPM stages (ST1, ST2) being integrated into said assembly. The invention also relates to a circuit arrangement (14) comprising a reversible blocking protection and fire protection element for the electric motor (M) and/or the series resistor assembly (1), diverse status signalling lines (24a to 24c) being used to evaluate and control the ventilating fan system.

Abstract: A circuit for controlling rotation speed of a computer fan includes a fan header for connecting to a 4-pin fan or a 3-pin fan, a jumper device, an amplifier, and a controller. The jumper device has a first pin for receiving a controlling signal, and connected to a first power source, a second pin connected to the fan header, and a third pin connected to the first power source. The amplifier has an input terminal connected to the third pin of the jumper device via an integrator. The controller has a first terminal connected to an output terminal of the amplifier, a second terminal connected to a second power source, and a third terminal connected to the fan header and connected to a positive input terminal of the amplifier via a resistor. The first pin of the jumper device is selectively connected to the second or third pin.

Abstract: A fan system includes a driving device, a speed detecting device and a logic device. The driving device generates a speed detecting signal and a predetermined alarm signal. The speed detecting device, which is electrically connected with the driving device, receives the speed detecting signal, and generates a low speed signal when the speed detecting signal is lower than a reference signal. The logic device is respectively electrically connected with the driving device and the speed detecting device, and generates an alarm signal when the logic device receives the predetermined alarm signal or the low speed signal.

Abstract: A voltage converting circuit for converting a first voltage signal into a second voltage signal for supplying voltage for an electronic component includes a photoelectric coupler and a connector. The photoelectric coupler includes a light-emitting element and a photosensor. The light-emitting element includes a first terminal configured for receiving the first voltage signal. The photosensor includes a first terminal connected to a power supply, and a second terminal configured for outputting the second voltage signal. The connector configured for connecting the photosensor and the electronic component. When the first voltage signal is at a high level, the light-emitting element emits light to turn on the photosensor, the power supply makes the voltage level of the second voltage signal sent out by the photosensor to satisfy a voltage demand of the electronic component.

Abstract: A fan rotation speed control circuit of a power supply system is provided, which is applicable for controlling the rotation speed of the fan according to a loading state outputted by the power supply system. The fan rotation speed control circuit of the power supply system includes a waveform generating module, for generating an oscillating waveform signal; a current retrieving module, for retrieving a current signal corresponding to the loading state; a rotation speed control signal generating module, for comparing the oscillating waveform signal with the current signal, and generating a rotation speed control signal; a signal amplifying module, for amplifying an amplitude of the rotation speed control signal and outputting the amplified rotation speed control signal to the fan, so as to control the rotation speed of the fan.