32results about How to "Good constant current characteristics" patented technology

The invention relates to a high-efficiency LED constant current driving circuit. The circuit comprises an input rectification filter circuit, a switch power supply management chip, an isolation switch transformer, a primary clamping circuit of the transformer, an output rectification filter circuit, an output current sampling circuit, a reference voltage generation circuit, a comparison circuit and a photoelectrical coupling circuit, wherein the input end of the input rectification filter circuit is connected with commercial AC electricity, while the output end is connected with a primary winding of the isolation switch transformer through the switch power supply management chip; the primary clamping circuit of the transformer is connected in parallel with the primary winding of the isolation switch transformer; the input end of the output rectification filter circuit is connected with the primary winding of the isolation switch transformer, while the output end is connected with LED load; an output current sampling circuit is connected in series with the LED load; the input end of the reference voltage generation circuit is connected with the LED load; and the input end of the comparison circuit is connected with the output current sampling circuit and the reference voltage generation circuit, while the output end is connected with the switch power supply management chip through the photoelectrical coupling circuit. The circuit improves the circuit integration degree, the reliability, the constant current precision and the circuit conversion efficiency.

The invention relates to semiconductor technology, in particular to a JFET device and a manufacturing method thereof. The JFET device of the present invention is characterized in that the junction depth of the P+ gate region 1 is uneven, from one end near the N+ drain region 2 to the junction of the P+ gate region 1 near the N+ source region 3. The depth gradually increases. The beneficial effect of the present invention is that the constant current characteristic is better, and the requirement of smaller constant current precision can be met. The invention is particularly applicable to JFET devices and their fabrication.

The invention relates to electronic techniques, and provides a constant-current drive circuit of an LED switching power supply. The constant-current drive circuit comprises a rectification filter circuit, a power tube, an RS flip-flop, an oscillator and an operational amplifier. Two input ends of the RS flip-flop are respectively connected with an output end of the operational amplifier and the oscillator, and a Q end of the RS flip-flop is connected with a grid of the power tube. The constant-current drive circuit of the LED switching power supply is characterized in that the operational amplifier is connected with the input ends of the RS flip-flop through a delay doubling circuit. The constant-current drive circuit of the LED switching power supply has the advantages that the delay doubling circuit is added in a loop circuit compared with an existing BUCK structured constant-current drive circuit, and enables output current to be unrelated to LED voltage, clock periods and intensity of inductance, and therefore the constant-current drive circuit is good in constant-current characteristic.

The invention relates to an inductive energy-storage microsecond-grade high-power pulse current source comprising an inductive charging circuit, an inductive discharging circuit and a clamping circuit, wherein the inductive charging circuit is a series loop which consists of an excitation power supply V2, an inductor L and a switch tube; the inductive discharging circuit is a series loop which consists of a loader, a fly-wheel diode D1 and the inductor L; and the clamping circuit is connected with the inductive charging circuit in a spanning way. The invention can generate a current-controllable high-power pulse power supply on the negative-resistance loader, has adjustable striking voltage, not only has very well constant-current characteristics, but also can fast respond to plasma arcs and realize the ultrafast switching of striking arcs and constant currents.

The present invention relates to a LED drive power supply and a dimming method with multi-channel current equalization output, the drive power supply includes a switch network module connected in sequence, an LCL-nT resonant network, a rectifier network and a load unit; wherein the switch network includes two The first bridge arm and the second bridge arm are connected in parallel, wherein the second bridge arm is used as a phase-shifted bridge arm to realize wide-range dimming control, and the load unit includes n LED loads with current sharing output. The invention can realize the constant and balanced output current of each channel under multiple different LED lamp voltages, and has the characteristics of simple circuit structure, good constant current characteristic, high current equalization precision, and the like.

The invention discloses a control circuit and method for a switching power converter. The switching power converter comprises a power conversion circuit, a sampling resistor and a switching power controller. Output currents are provided for the switching power converter through the power conversion circuit. The switching power controller comprises a power switch, an error amplifier, a comparator circuit and a logic and drive circuit. The power switch is used for controlling power supply of the power conversion circuit, and the sampling resistor is coupled to the power switch and provides sampling voltage signals. The error amplifier is used for receiving the output current equivalent value and the preset threshold value of the switching power converter so as to generate error voltages, wherein the output current equivalent value indicates the amplitude of the output currents of the switching power converter. The comparator circuit is used for comparing the sampling voltage signals and the error voltages and generating comparison output signals. The logic and drive circuit is used for generating drive signals, wherein when the comparison output signals generated by the comparator circuit indicate that the sampling voltage signals excess the error voltages, the drive signals switch off the power switch.