For the last several decades, every engineering task related to processing control is realized by the use of PLC (Programmable Logic Controller). If we are talking about induction motor control, which is the most common case, usually a VFD (Variable... Read more

The post Learn how to use PLC and VFD for pump control: Power and control circuits analysis appeared first on EEP - Electrical Engineering Portal.

In the domain of electrical engineering, seal-in contacts stand as pivotal components in control circuits, ensuring the sustained operation of electrical devices beyond the initial activation. These mechanisms play a critical role in maintaining the energized state of circuit elements,... Read more

The post Mastering schematic drawings: Analyzing seal-in contacts in motor control circuits appeared first on EEP - Electrical Engineering Portal.

Control circuits

to wire a motor control circuit

Today many instances of IEEE 1149.1 Tap domains are included in integrated circuits (ICs). While all TAP domains may be serially connected on a scan path that is accessible external to the IC, it is generally preferred to have selectivity on which Tap domain or Tap domains are accessed. Therefore Tap domain selection circuitry may be included in ICs and placed in the scan path along with the Tap domains. Ideally, the Tap domain selection circuitry should only be present in the scan path when it is necessary to modify which Tap domains are selected in the scan path. The present disclosure describes a novel method and apparatus which allows the Tap domain selection circuitry to be removed from the scan path after it has been used to select Tap domains and to be replaced back into the scan path when it is necessary to select different Tap domains.

The present application discloses a control circuit for a power tool and a method for manipulating the power tool. The control circuit has a detection circuit for battery packs, a calculating control circuit, a battery capacity indicating circuit for indicating the calculation result of the battery capacity, and a current measure and calculating circuit for measuring the current flowing through motors. The calculation result further includes the voltages consumed by the battery pack internally and the discharge loop. The method for manipulating the power tool includes pressing the switch to electrically connect the motor and the battery pack, measuring the parameters of the battery pack and allowing the motor to operate or not according the measured parameters. Further, after the motor is in operation, the battery capacity is calculated and the results are displayed.

A control circuit for a fan includes a fan controller, a switch controller, and a frequency detector. When a pulse-width modulation (PWM) signal output pin of the fan controller outputs PWM signals, the frequency detector outputs a high level signal, connecting an input pin of the switch controller to an output pin of the switch controller. The fan receives the PWM signal. When the PWM signal output pin of the fan controller does not output PWM signals, the frequency detector outputs a low level signal, such that the output pin of the switch controller does not output any signal. In this state, the fan receives a high level signal through a resistor and a power supply, enabling the fan to continue operating.

A rotation speed control circuit is disclosed. The rotation speed control circuit includes a temperature-controlled voltage duty generator, a pulse-width signal duty generator, a multiplier and a rotation speed signal generator. The temperature-controlled voltage duty generator converts temperature-controlled voltage to digital temperature-controlled voltage and executes linear interpolation operation according to a first setting data so as to output temperature-controlled voltage duty signal. The pulse-width signal duty generator coverts pulse-width input signal to a digital pulse-width input signal and executes linear interpolation operation according to a second setting data so as to output a pulse-width duty signal. The temperature-controlled voltage duty signal and the pulse-width duty signal are executed for multiplication by the multiplier so as to output mixing-duty signal. The rotation speed generator receives the mixing-duty signal and a third setting data, and executes a minimum output duty operation so as to output a pulse-width output signal.

A latch circuit includes a latch unit and a clock propagation suppressing unit. The latch circuit holds and outputs input data of 0 or 1. The clock propagation suppressing unit compares the input data input to the latch unit with output data output from the latch unit. When it is detected that the input data matches the output data at 0, or that the input data matches the output data at 1, an externally input clock signal is prevented from propagating to the latch unit.

A method for charging an assembled battery including series circuits connected in parallel, each of the series circuits including series-connected lead storage batteries, using a single charger is provided. The method includes: a first step of obtaining a first index value, corresponding to a resistance value of a first series circuit with a correlative relationship, the first series circuit having a lowest resistance value; a second step of obtaining a second index value corresponding to a resistance value of a second series circuit with a correlative relationship, the second series circuit having a highest resistance value; a third step of performing normal charging, in which the assembled battery is charged with a first amount of charge corresponding to the first index value; and a fourth step of performing refresh charging, in which the assembled battery is charged with a second amount of charge corresponding to the second index value.

Circuitry and techniques to measure, at the battery's terminals, characteristic(s) of the charging signal applied to the battery/cell during the recharging operation and, in response to feedback data which indicates the charging signal is out-of-specification, control or instruct the charging circuitry to adjust characteristic(s) of the recharging signal (e.g., the amplitude of the voltage of and/or current applied to or removed from the battery during the charging operation). For example, a rechargeable battery pack comprising a battery, and controllable switch(es), a current meter and voltmeter, all of which are fixed to the battery. Control circuitry generates control signal(s) to adjust a current and/or voltage of the charging signal using the feedback data from the current meter and/or voltmeter, respectively.

A line voltage control circuit for use with a multi-string LED drive system which provides a common line voltage for multiple LED strings that are connected to respective current sink circuits at respective junctions. An error amplifier receives the minimum junction voltage and a reference ‘desired junction voltage’ at respective inputs, and a voltage regulator outputs the line voltage in response to a voltage applied to a feedback input. A comparator toggles an output when the maximum junction voltage (Vmax) exceeds a reference limit (Vlimit). A multiplexer receives the error amplifier output and a fixed voltage at respective inputs and provides one of the signals to the regulator's feedback input in response to the comparator output. When Vmax>Vlimit, the fixed voltage is provided to the feedback input and the line voltage is reduced, thereby protecting low voltage current sinks from potentially damaging high voltages.

A DC-DC converter includes a first amplifier that amplifies a first difference between a first reference voltage and a feedback voltage corresponding to an output voltage, a second amplifier that amplifies a second difference between the first reference voltage and an integrated value of the feedback voltage, and a controller that controls a switching circuit to change the output voltage when the first difference reaches the second different.

A controller used in a buck-boost converter includes a clock generator, an error amplifying circuit, a comparing circuit, a proportional sampling circuit, a logic circuit, a pulse width increasing circuit, first and second driving circuits. Based on a clock signal generated by the clock generator, the proportional sampling circuit samples the difference between a current sensing signal and a compensation signal generated by the error amplifying circuit, and generates a proportional sampling signal. The pulse width increasing circuit generates a sum control signal based on the proportional sampling signal and a logic control signal generated by the logic circuit, wherein a modulation value adjusted by the proportional sampling signal is added to the pulse width of the logic control signal to generate the pulse width of the sum control signal. The first and second driving circuits generate driving signals based on the sum control signal and the logic control signal.

A method for controlling voltage crossing a power switch of a switched-mode power converter includes the steps of: controlling a switch frequency of the power switch of the switched-mode power converter to a first frequency as activating the switched-mode power converter; and then changing the switch frequency of the power switch to a second frequency after the switched-mode power converter is activated for a predetermined time; wherein the first frequency is lower than the second frequency.

In some aspects of the invention, overcurrent protection is carried out by suppressing fluctuations in current flowing through a switching element after overcurrent detection. A peak current reaching time detection circuit detects a peak current reaching time needed until current flowing through a switching element reaches a peak value. A difference voltage detection circuit, including a ½ time detection circuit which detects a time of ½ an ON time of the preceding cycle of the switching element, detects difference voltage between reference voltage used when detecting overcurrent flowing to a load and a signal which has detected current flowing through the switching element for the ½ time. A delay time adjustment circuit, based on at least one of the peak current reaching time and difference voltage, carries out adjustment and control of a delay time occurring until the time when the switching element is turned off after detecting the overcurrent.

A power converting circuit includes an upper gate switch, a transistor, a current source circuit, a comparator circuit, a delay circuit, and a pulse width modulation signal generating circuit. The transistor and the current source circuit provide a reference signal. The comparator circuit generates a comparing signal according to the reference signal and an output signal provided by the upper gate switch. The delay circuit generates a delay signal according to the comparing signal and a clock signal. The pulse width modulation signal generating circuit generates a control signal for the upper gate switch according to the delay signal and the clock signal for configuring the conduction status of the upper gate switch. The power converting circuit adjusts the conduction time of the upper gate switch according to the reference signal and the output signal.

A step-down regulator comprising a pseudo constant on time control circuit is disclosed, comprising an on-time generator configured to receive a switching signal provided by the step-down regulator and a control signal provided by the pseudo constant on time control circuit, and generates an on-time signal; a feedback control circuit configured to receive a feedback signal representative of the output voltage of the step-down regulator and generate an output signal; and a logic control circuit coupled to the on-time generator and the feedback control circuit to receive the on-time signal and the output signal and generating the control signal, and a power stage configured to receive an input voltage and the control signal and generate the switching signal.

A power control circuit for a power supply system including a control unit, a driving circuit and a power supply unit is disclosed. The power control circuit includes a current detection unit, a voltage detection unit and a power detection unit. The current detection unit is used for detecting a current signal. The voltage detection unit is used for detecting a voltage signal. The power detection unit is connected with the current detection unit, the voltage detection unit and the control unit for acquiring a power signal according to the current signal and voltage signal. By comparing an adjustable power reference signal with the power signal, the control unit issues a control signal to the driving circuit. In response to the control signal, the power supply unit is driven by the driving circuit to output an adjusted power to the load according to the adjustable power reference signal.

An electronic lock with power failure control circuit includes a lock mechanism having a latchbolt movable between extended and a retracted positions and an electrically powered lock actuator to lock and unlock the latchbolt. The power failure control circuit includes a microcontroller and the lock is connected to a primary power source and an auxiliary power source, preferably supercapacitors and charger that can be turned on by the microcontroller and off when the charger signals a full charge. A power monitor circuit detects low voltage on the primary power supply and sets a power failure interrupt causing the microcontroller to execute power failure instructions that control the actuator so that the lock is placed into a desired locked or unlocked final state during the power failure. upon detection of the return of good power, the system resets the lock.

The present disclosure relates to a delay control circuit arranged for adding delay to a signal. The delay control circuit includes a driver circuit arranged to receive a first signal and to output a second signal. The driver circuit includes a variable load arranged for outputting the second signal by adding delay to the first signal. The delay control circuit also includes a control circuit arranged to receive the first signal and to control the variable load of the driver circuit based on a current state of the first signal and on a control signal indicative of an amount of delay to be added to the first signal in the current state.

An example circuit includes: a slew rate driver configured to provide an output voltage; a first voltage provider configured to provide a first input voltage to the slew rate driver in response to the output voltage being within a first range; and a second voltage provider configured to provide a second input voltage to the slew rate driver in response to the output voltage being within a second range. The slew rate driver is further configured to change the output voltage based at least in part on the first input voltage or the second input voltage.

A device for controlling a first control gate transistor, including: a second transistor and a third transistor series-connected between a first and a second terminals of application of a power supply voltage, the junction point of these transistors being connected to the gate of the first transistor; a terminal of application of a digital control signal; a circuit for generating an analog signal according to variations of the power supply voltage; and for each of the second and third transistors, a circuit of selection of a control signal of the first transistor representative of said digital signal or of said analog signal.

A printhead cartridge cradle is provided having a frame, a printed circuit board pivotally supported by the frame, a cover pivotally supported by the frame to pivot between a closed position at which a printhead cartridge is secured within the frame and the printed circuit board is pivoted to connect control circuitry on the printed circuit board with a controller of the secured cartridge and an open position at which access for the cartridge with the frame is provided and the printed circuit board is pivoted to disconnect the control circuitry and controller, and a motor operatively connected to a maintenance gear and actuator arrangement and a wiper gear and actuator arrangement for maintaining and wiping a printhead of the secured cartridge under control of the connected control circuitry.

Patients with mood and anxiety disorders share the same abnormalities in regions of the brain involved in emotional and cognitive control. The findings