122results about How to "Extended on-time" patented technology

A power converter includes a switch controller generating a pulse signal controlling a switch to emulate peak current mode control. The switch controller generates a control voltage from a representation of an output voltage of the power converter and a reference voltage. Based on the control voltage and a representation of an input voltage of the power converter, the switch controller determines a peak current in that switching cycle. If the peak current detected exceeds a maximum peak current, an on-time of the pulse signal in the next switching cycle is decreased. The power converter also provides short circuit or overload protection by increasing an off-time of the pulse signal until the off-time exceeds a transformer reset time of a transformer. If the switch period increased to prevent short circuit or overload exceeds a limit, the pulse signal is shut off immediately.

The invention discloses a three-level inverter narrow-pulse elimination and midpoint voltage control method and device. The method comprises the following steps of: judging whether the current given voltage space vector stays at a low modulation factor, if yes, then the resultant vector forming the current given voltage space vector comprises two groups of positive and negative small vectors, starting with a zero vector, and conducting in a thirteen-section type conduction way with only one phase level change every time; or else, conducting in a seven-section type conduction way starting with a small vector; calculating the action time of the resultant vector via the current given voltage space vector; calculating a time control factor according to the obtained midpoint voltage offset and the output current direction; redistributing the action time of positive and negative small vectors according to the conduction time and the time control factor of the resultant vector; and obtaining the driving pulse of a power switch tube in a three-level inverter according to the action time of the redistributed positive and negative small vectors. The narrow pulse is eliminated by using the zero vector, and the midpoint voltage is controlled by using two groups of positive and negative small vectors.

The invention discloses a DC/DC converting circuit which comprises a DC/DC converting unit, a bootstrapping driving unit and a controller. The DC/DC converting unit comprises a first power tube and a second power tube. The bootstrapping driving unit comprises a driving chip, a diode and a bootstrapping capacitor. The diode, the bootstrapping capacitor and the first power tube form a charging loop. The bootstrapping capacitor provides driving charges for the second power tube. Under the situation that input voltage meets preset conditions, the controller lowers the switching frequency and the duty ratio of the first power tube, and during first power tube connecting, charges charged into the bootstrapping capacitor can maintain driving charges needed by the second power tube. The DC/DC converting circuit is simple in structure and high in converting efficiency. The invention further discloses a double-way DC/DC converting circuit, a two-quadrant DC/DC converting circuit and a four-quadrant DC/DC converting circuit.

The invention discloses a source electrode drive circuit and a controlling method thereof. The source electrode drive circuit comprises controlling transistors, a power supply capacitor and a current feed diode, wherein the controlling transistor are connected between the second end of a main switch pipe and the ground; the two ends of the power supply capacitor receive approximately constant bias voltage; the cathode of the current feed diode is connected to the control end of the main switch pipe; the anode of the current feed diode is connected with the second end of the main switch pipe; the controlling transistors are conducted and switched out periodically to enable the main switch pipe to be conducted and switched out correspondingly along the controlling transistors; the conducting time quantum of the main switch pipe comprises a first stage from starting in switching out state to completely conducting, and a second stage of being in completely conducting state; in the first stage, the controlling transistors provide approximately constant starting current. The source electrode drive circuit prolongs the conducting time of the main switch pipe, so as to restrain EMI greatly; meanwhile, time delay in switching out process of the main switch pipe is avoided, so as to reduce additional power consumption.

A power converter includes a main switch to which a capacitor is connected through a sub-diode. A primary coil of a transformer and a sub-switch are joined parallel to the capacitor. A main diode is coupled in series with the main switch. A sub-diode and a secondary coil of the transformer are connected parallel to the main diode. The rate of a rise in voltage across the main switch when turned off is suppressed by the rate of charging of the capacitor. Subsequently, by turning on the sub-switch, the current flowing through the main diode to be delivered to the transformer, thereby causing the current flowing through the main switch when turned on to be decreased by the sub-inductor.

A switching regulator includes a first switching regulator corresponding to a master channel, and a second switching regulator corresponding to a slave channel. The first switching regulator generates first output voltage Vout1 by a constant on-time system in which on-time is constant. On the other hand, the second switching regulator monitors a first switching signal and a second on-time control circuit determines on-time of a second switching signal in accordance with lapse time from the rising time of the first switching signal to the rising time of a second switching signal.

The invention discloses a switching state control circuit and control method and a fly-back converter. A first voltage sampling signal characterizing the input voltage information is obtained, and theconduction time of a synchronous rectifier tube is adjusted according to the change state of the first voltage sampling signal so as to adjust the absolute value of a negative current flowing througha secondary winding, wherein the negative current is used to discharge a junction capacitor of a main power tube so as to reduce the drain-source voltage of the main power tube. The main power tube can be switched on in a ZVS (Zero Voltage Switching) mode under different input voltages. The magnitude of the negative current is appropriate, and no extra circulating current will be generated. Adaptive control is realized.

The invention provides a linear high voltage LED driving circuit comprising a rectifier bridge pile, two or more LED strings, driving switches matched with the LED strings, a current sampling circuit used for detecting current of each driving switch, and a constant current control circuit used for controlling each driving switch to conduct a resistant; the constant current control circuit and the driving switches are used for controlling the at least two LED strings to be partially or fully conducted for illumination according to the changes of the DC pulse voltage, so conducted illumination time of the LED string can be improved in one voltage pulse period, and power consumption of the driving switches is reduced, thus greatly improving LED driving efficiency.

The present invention discloses a switching power supply control chip and a flyback AC-DC converter. The switching power supply control chip comprises a sampling unit, a slope compensation unit, a PWM comparator unit, a line voltage compensation control module, a line voltage compensation unit, a cycle-by-cycle current-limiting protection unit, an or gate, an RS trigger, an oscillator and a driving unit. The switching power supply control chip provided by the present invention detects the conduction time of an external power MOS transistor by the line voltage compensation control module, when the conduction time is greater than the first preset time, within the conduction time of the next external power MOS transistor, controls the line voltage compensation unit not to carry out the line voltage compensation on a reference voltage within the second preset time, thereby preventing the situation that an output overcurrent point and a recovery point under a low voltage are not increased along with the increase of the line voltage, enabling the conduction time of the external power MOS transistors to be longer in each cycle, and improving the output power.

The invention discloses a constant voltage output switching power supply with a high power factor, which is composed of a rectifying and filtering circuit, a power converter, a control circuit, an output voltage feedback circuit, an inductive current zero-crossing feedback circuit and a chip power supply circuit. The constant voltage output switching power supply is characterized in that alternating current is inputted and converted into direct current through the rectifying and filtering circuit, the direct current is inputted into the power converter, the direct current is outputted to a load circuit from the power converter, then detection is carried out on a main power circuit through the output voltage feedback circuit, the inductive current zero-crossing feedback circuit and the chip power supply circuit, an acquired result is inputted into the control circuit so as to enable the control circuit to operate and obtain a control scheme, and output of the control circuit is transmitted to the power converter so as to perform control on the power converter. According to the constant voltage output power supply system with a high power factor, the turn-on time of a power switch tube is controlled to be constant through design of the control circuit and the feedback circuit; constant voltage output can be achieved in a full voltage range, and a high power factor can be ensured.

A transistor with an electrical overstress (EOS) protection may include an active region, a plurality of impurity regions and a conduction pattern. The active region may be formed in a substrate. The impurity regions may be formed in the active region and arranged at a predetermined or given distance with respect to each other. The conduction pattern may be arranged between each of the impurity regions in a meandering shape, and the conduction pattern may include a center portion connected to a ground terminal. Therefore, a transistor with EOS protection, a clamp device, and an ESD protection circuit including the same may increase an on-time of a clamp device and may sufficiently discharge a charge due to the EOS by including a conduction pattern configured with gates that are connected with respect to each other in a meandering shape.

The invention discloses an alternating current rectifying circuit and an alternating current rectifying method for driving a light-emitting diode (LED) module. The method comprises that after an alternating current is rectified, and the rectified alternating current is output to a positive half cycle rectifying branch circuit of the LED module when an alternating current module is in a positive half cycle. When the alternating current module is in a negative half cycle, charging is carried out according to the alternating current output by the alternating current module, and when the alternating current module is in the positive half cycle, electro-discharge is carried out, and the alternating current is output to a negative half cycle rectifying branch circuit of the LED module. When the alternating current module is in the negative half cycle, the alternating current is rectified, and the alternating current is output to a positive half cycle rectifying branch circuit of the LED module. When the alternating current module is in the negative half cycle, the electro-discharge is carried out, and the alternating current is output to a negative half cycle feed branch circuit of the LED module. When an output voltage signal is higher than a preset voltage threshold value, an overvoltage protection branch circuit of the LED module is shut off. By means of the alternating current rectifying circuit, stability of output voltage can be improved, and luminous efficiency of the LED module is improved.

The invention relates to a multifunctional household-based heat metering distribution management device and a metering method, the existing heat metering device has the defects such as large installation occupy space, large error, multiple user limitations and the like. The device comprises a water supply main pipe (1) and a backwater main pipe (2), wherein a group of user pipes (3) are connected in parallel between the water supply main pipe and the backwater main pipe, each user pipe (3) is connected with a radiator (4), the radiator (4) is connected with an intelligent valve (5), the intelligent valve is connected with indoor temperature setting metering equipment (13), a total heat meter (9) is installed on the backwater main pipe, a pressure measurement device is connected between the water supply main pipe and the backwater main pipe, the intelligent valve (5), and the total heat meter (9) and the pressure measurement device are all connected with a center controller (10). The device in the invention is used for household-based heat metering.

The invention discloses an LED display screen compensation circuit and a method thereof, and belongs to the technical field of LED display. The LED display screen compensation circuit comprises a reference voltage adjusting module, a compensation enabling control module, a current mirror module, a PWM compensation module and a PWM transmission module. The reference voltage adjusting module is usedfor setting different compensation levels according to the reference voltage so as to carry out compensation of different degrees; the compensation enabling control module enables the PWM transmission module and the current mirror module to be started by pulling up an enabling signal to start a non-first-row low grey balance adjusting function and a first-row dark adjusting function; the currentmirror module outputs current to the outside under control of the compensation enabling control module; the PWM compensation module compensates for low grey balance and first line darkness according to requirements, and transmits compensated PWM signals to the current mirror module to control current output; and the PWM transmission module outputs the compensated PWM signal, and outputs a signal PD to control whether the current of the current mirror module is output or not.

The invention relates to a method for achieving soft starting of a PWM convertor. According to the method, a sawtooth wave generating circuit, a voltage comparator and an AND gate are utilized for achieving soft starting of the PWM convertor. The functional block diagram for achieving the technology is shown as the attached picture. The treatment process comprises that firstly, the sawtooth wave generating circuit is utilized for converting an input drive signal into a sawtooth wave, wherein the frequency and the duty ratio of the sawtooth wave is unchanged; then the voltage comparator is adopted for comparing the sawtooth wave and a slowly-rising reference voltage, and a pulse voltage signal is obtained, wherein the duty ratio of the pulse voltage signal is gradually increased; finally, the pulse voltage signal and an input drive voltage are compared through the AND gate to obtain an output drive voltage, wherein the duty ratio of the output drive voltage is gradually increased. At the moment of starting up, the duty ratio of the drive voltage is gradually increased, after a switching power supply works normally, the voltage comparator outputs a high level all the time, and the output drive voltage and the input drive voltage are completely equal. Therefore, soft starting of the PWM convertor is achieved, and the method has broad application prospects in the field of power sources.

The invention provides a control device and a control method, which can detect current offset amount under the moving state of the AC motor conducting phase control of voltage, and can inhibit or eliminate the current offset amount through controlling a voltage waveform. A control device of the alternating current motor controls the voltage waveform on the condition of considering the current offset amount of the AC motor (9) having current detection units (97U-97W) and a phase detection unit (95). The control device comprises voltage phase setting portion (12), an offset detecting unit (11), a switch control unit (13) and a waveform switching unit (16).

The invention relates to a temperature control module for a glass electric kettle. The electric kettle includes a glass kettle body, a far-infrared electrothermal film, a plurality of temperature detection circuits, a main control chip and a second driving circuit, wherein the far-infrared electrothermal film is mounted on the outer surface of the bottom of the glass kettle; after being connected in series with a temperature control switch, the far-infrared electrothermal film is connected with an external power supply to form a main working circuit; a plurality of area temperature signals of the bottom of the glass kettle body are transmitted to the main control chip through the temperature detection circuits; when the difference between the area temperature signals exceeds a certain value, the main control chip sends a control signal to the second driving circuit, and the second driving circuit disconnects the temperature control switch, so as to cut off the power supply to the far-infrared electrothermal film. The temperature control module for the glass electric kettle achieves overall monitoring of the temperature of the bottom of the glass electric kettle; when the local temperature is too high, the power supply to the far-infrared electrothermal film is temporarily cut off, so as to effectively protect the glass electric kettle, eliminate potential safety hazards, and improve the product reliability and stability.

The invention relates to a glass electric kettle power control module. An electric kettle comprises a glass kettle body, a far infrared electric heating film and a heating control circuit. The far infrared electric heating film is disposed on the bottom outer surface of the glass kettle body. The heating control circuit controls the far infrared electric heating film and comprises a power measurement circuit, a master control chip and a power control circuit. The power measurement circuit measures real-time power of the far infrared electric heating film during operation and transmits power data to the master control chip. The master control chip adjusts power-on time of the far infrared electric heating film through the power control circuit so as to control the power of the far infrared electric heating film. The glass electric kettle power control module is capable of controlling the powers of different far infrared electric heating films accurately, is applicable to coating far infrared electric heating films to bottoms of glass kettles in one batch or in different batches, is widely applicable, and allows glass electric kettles to be convenient to produce in batch and popularize and use.

Disclosed are a lighting device and a method thereof. The lighting device is provided with an input power source which is a pulsation direct-current power source, and comprises a lighting unit, a detecting unit and a control unit. The lighting unit is provided with a plurality of lighting sets and switch units, wherein the switch units are used for connecting the lighting sets in series and/or parallel. The detecting unit is used for detecting states of the input power source input into the lighting unit. The control unit is coupled to the detecting unit and the switch units and controls the switch units according to detecting results of the detecting unit so as to enable conduction voltage of the lighting unit to vary along with the input power source. Accordingly, the conduction voltage of the lighting unit can be adjusted, and conduction time of the lighting unit within a period of the input power source is prolonged.

The invention provides a driving circuit of a liquid crystal panel. The driving circuit comprises a gate driver, a source driver, a plurality of gating lines and a plurality of data lines, wherein a plurality of pixel units are defined by the gating lines and the data lines; each pixel unit comprises a thin film transistor, a public electrode, a pixel electrode and a correction capacitor; the thin film transistor is electrically connected with the gate driver and the source driver through one gating line and one data line respectively; the public electrode and the pixel electrode form a liquid crystal capacitor; the thin film transistor comprises a gate and a drain; and the correction capacitor is electrically connected between the gate and the drain for correcting parasitic capacitance formed by the gate and the drain due to structural characteristic. The influence of the parasitic capacitance on the thin film transistor is reduced by arranging the correction capacitor, so that the accuracy in control of the thin film transistor is improved, and phenomena of variation in transmittance and contrast abnormality caused by abnormal deflection of liquid crystal molecules are avoided.