34results about How to "Extended off time" patented technology

The invention discloses a switched capacitor type high-bandwidth envelope tracking power supply circuit which comprises a step wave voltage generating circuit and an A-class linear amplifier. The stepwave voltage generating circuit is in cascaded connection with the A-class linear amplifier. The output of the step wave voltage generating circuit is used as input of the A-class linear amplifier. The step wave voltage generating circuit is obtained through serially connecting n switched capacitor circuits with the same structure. (1/n):1 frequency reduction of the switching frequency of the switch tube in each switched capacitor circuit relative to the frequency of a tracking signal can be realized. Furthermore the on time or off time of a switch tube is effectively prolonged, thereby realizing sufficient switching-on or switching-off, and improving working performance and reliability in a high-bandwidth tracking condition. Compared with a traditional method, the switched capacitor typehigh-bandwidth envelope tracking power supply circuit has advantages of greatly reducing number of power supplies, reducing complexity degree and cost of the circuit, and improving system efficiency.

The present invention relates to a LED drive circuit with an adjustable current. Electric supply is subjected to voltage reduction by a transformer and then is output to a rectification filtering unit, the rectification filtering unit outputs the electric supply to a LED lamp set for power supply, a negative pole of the LED lamp set is connected with an MOS tube Q4, a sampling resistor R6 and a feedback comparison unit in order to achieve constant current of a LED drive circuit, the feedback comparison unit outputs a current to a PWM generation unit, the PWM generation unit outputs PWM waveform signals to a drive unit, the drive unit improves the switching motion response speed for drive of the MOS tube Q4, a controller in the PWM generation unit performs processing of the external currentadjusting command from a serial port, the frequency of outputting PWM signals by the PWM generation unit is regulated to achieve adjustment of the size of a current of the LED lamp set. The LED drivecircuit with an adjustable current can achieve regulation in a range from none to a set maximum value, the provided drive unit circuit can effectively accelerate the on-off time of the MOS tube and can eliminate the peak and the burr of the gate waveform of the MOS tube so as to greatly improve the efficiency and the stability of the LED drive circuit.

The invention provides an insulated gate bipolar transistor. The insulated gate bipolar transistor comprises a first base region, a second base region, an emitter region, a gate oxide layer, a buffer region, a first collector electrode area, a second collector electrode area and a third collector electrode area. The second base region, the emitter region and the gate oxide layer are sequentially arranged on one side of the first base region, and the buffer region, the first collector electrode area, the second collector electrode area and the third collector electrode area are sequentially arranged on the other side of the first base region. The conduction type of the second base region, the conduction type of the first collector electrode area and the conduction type of the second collector electrode area are opposite to the conduction type of the first base region. The conduction type of the emitter region, the conduction type of the buffer region and the conduction type of the third collector electrode area are the same as the conduction type of the first base region. The maximum thickness of the third collector electrode area is equal to the maximum thickness of the second collector electrode area, and the dosage concentration of the buffer region, the dosage concentration of the first collector electrode area and the dosage concentration of the third collector electrode area are gradually increased, so that a bipolar transistor structure is formed.

The invention provides a system for providing working frequency for a switching power supply converter. The system comprises a feedback input circuit, a variable frequency and intermittent mode control circuit, a logical control circuit, an oscillator and a PWM (Pulse Width Modulation) generator, wherein the feedback input circuit is used for feeding a load state back into an integrated circuit through an optical coupling device and generating a first control signal; the variable frequency and intermittent mode control circuit is configured to receive the first control signal and generate a first output signal related to the frequency; the logical control circuit is configured to receive the first output signal and a sawtooth wave signal of the oscillator to form a second output signal; the oscillator is configured to receive the second output signal to control the charging and the discharging of a capacitor through current to form a third output signal (a sawtooth wave signal); and the PWM generator is configured to receive the second output signal and the third output signal to form a fourth output signal for switching on or off a power switch of the switching mode power supply converter. Through the system, the working frequency of a switching power supply is controlled to change along with the change of a load, so that the aim of reducing power consumption is achieved, and the efficiency of the system is increased.

The invention discloses a hybrid integrated IGBT (insulated gate bipolar translator) drive circuit and belongs to the technical field of drive of a power device. The circuit comprises a hybrid integrated IGBT drive chip and a voltage stabilizing tube; the hybrid integrated IGBT drive chip selects QP12W05S-37(A); the voltage stabilizing tube selects DZ402 and DZ403; the voltage stabilizing tube is connected with the hybrid integrated IGBT drive chip; an external signal is input to the hybrid integrated drive chip after being limited by a resistor; the hybrid integrated drive chip outputs stable voltage signal to drive on/off of the IGBT; the circuit has the function of outputting the signal and limiting the amplitude, so that the signal received by the grid of the IGBT is within a safe range, and current at two ends of the IGBT is detected at the same time. The drive circuit locks, outputs and emits an error signal to ensure the safety of the IGBT when the current value exceeds a limit value. The hybrid integrated IGBT drive circuit has the advantages that the drive circuit has a power supply, and has the functions of blocking and restoring a fault, and adjusting protective soft turn-off time.

The invention provides a brushless direct current motor noise suppression driving method, and the method comprises the following steps: establishing a model, and obtaining the turn-off time of a delayed turn-off phase during commutation and the turn-on time of a delayed turn-on phase during commutation; judging whether the motor is in high-speed operation or low-speed operation; during high-speed operation, delaying the turn-off time of the turn-off phase during commutation; and during low-speed operation, delaying the on-time of the on-phase during commutation. According to the driving method for noise suppression of the brushless direct current motor, the turn-off time of the turn-off phase or the turn-on time of the turn-on direction during phase commutation is delayed by judging whether the motor is in high-speed operation or low-speed operation, the torque ripple during phase commutation is reduced, and finally the noise of the motor is reduced.

The invention discloses an LED silicon-controlled rectifier phase-controlled dimmer and a stroboflash eliminating method and a stroboflash eliminating circuit thereof. The circuit comprises a rectifier module and a stroboflash control module. The stroboflash control module compares the phase adjustment values of two adjacent rectification periods, and extends the turn-off time of an LED lamp string in the rectification period with smaller phase adjustment value to make the turn-off time of the LED lamp string in the rectification period with smaller phase adjustment value consistent with the turn-off time of the LED lamp string in the rectification period with larger phase adjustment value. Thus, the conduction time of the LED lamp string is the same in adjacent rectification periods, and stroboflash is eliminated.

The invention discloses an electro-hydraulic emergency turn-off system for a test process. The system comprises a plurality of remote control button boxes which are connected in parallel through a multi-core cable, an electric control panel which is connected with the plurality of remote control button boxes, and is provided with a data communication interface, an electromagnetic valve box which is connected with the electric control panel, an induction gas pipeline and a hydraulic control panel, wherein one end of the induction gas pipeline is connected with the electromagnetic valve box; and the hydraulic control panel is connected with the other end of the induction gas pipeline. The invention further discloses a control method of the electro-hydraulic emergency turn-off system for testing the process, the electro-hydraulic emergency turn-off system is controlled through bus control or signal input so that the ground test process is isolated from a test shaft, and the response time of the turn-off system is shortened in an electric signal control mode.

In one embodiment, an LED driving circuit can include: (i) a sense circuit configured to sense an inductor voltage, and to generate a sense voltage signal; (ii) a protection control circuit configured to activate a first protection control signal in response to a comparison of the sense voltage signal against a first reference voltage to indicate an LED device is in a first load state; (iii) the protection control circuit being configured to activate a second protection control signal in response to a comparison of the sense voltage signal against a second reference voltage to indicate the LED device is in a second load state; and (iv) a PWM control circuit configured to control a power switch according to the first protection control signal or the second protection control signal, based on the load state of the LED device.

The invention discloses a driving control circuit and method. The power supply end of the driving control circuit is connected to a power supply circuit. In a start process, the driving control circuit is started when the voltage of the power supply end reaches starting voltage. The driving control circuit comprises a PWM signal generation circuit for generating a PWM signal used for determining turn-on time and turn-off time and used as a control signal for a switch; and an auxiliary start circuit for comparing, after the driving control circuit is started, a sampling signal representing the output voltage with first reference voltage, and entering an auxiliary start mode when the sampling signal is lower than the first reference signal. In the auxiliary start mode, the turn-off time represented by the PWM signal is prolonged to reduce switching frequency, or the turn-on time represented by the PWM signal is prolonged to increase an output voltage rise rate.

The invention discloses a rail conveying system for a biochemical analyzer. The rail conveying system comprises a first bracket, wherein the first bracket is provided with a conveying belt assembly and a limit baffle mechanism. The limit baffle mechanism is arranged at the sample outlet end of the conveying belt assembly; the limit baffle mechanism is used for restricting the sample rack on the sample outlet end of the conveying belt assembly; the first bracket is further provided with a pushing mechanism. The pushing mechanism is used for urging the sample rack on the sample outlet end of the conveying belt assembly away from the conveying belt assembly. The rail conveying system can be set horizontally in the biochemical analyzer to realize the butt joint with the longitudinal rail in the biochemical analyzer, so that the buffer amount of the sample rack can be greatly increased on the premise of not increasing the length of the biochemical analyzer.