Inverse-excitation type is without optocoupler thick film DC/DC Switching Power SupplyTechnical field
The present invention relates to power electronic technology and microelectric technique, specifically relate to inverse-excitation type without optocoupler thick film DC/DC Switching Power Supply.
Background technology
Tradition inverse-excitation type DC/DC Switching Power Supply many employings photoelectrical coupler is as isolation and control feedback element.As everyone knows, photoelectrical coupler is formed by fixing encapsulation by light-emitting diode and phototriode (or diode), and its coupling efficiency is vulnerable to temperature and time impact.
Photoelectrical coupler after experiment of high-temperature load, can cause Switching Power Supply index seriously overproof, even lost efficacy, therefore have a strong impact on power supply reliability.
The more effective solution of another kind adopts secondary magnetic feedback isolation and control circuit, such as Chinese utility model patent application number: 201020662274.4 technical schemes announced, but complexity, the increase volume of circuit can be increased again like this and increase cost.
Summary of the invention
Technical problem to be solved by this invention is to provide a kind of sharp formula without optocoupler thick film DC/DC Switching Power Supply, overcome the high temperature service life shortcoming of photoelectrical coupler, the puzzlement of complexity, volume and the cost of avoiding secondary Magnetic isolation to feed back, can have again the feature that circuit is simple, good output, dynamic response are fast, hermetically metal sealing, good heat dissipation, reliability are high.
For solving the problems of the technologies described above, the invention provides following technical scheme: inverse-excitation type, without optocoupler thick film DC/DC Switching Power Supply, comprises and covers copper Al2o3ceramic substrate, SMT components and parts, dual inline type metal air-tight seal casing, described dual inline type metal air-tight seal casing soldering is in covering copper Al2o3the ceramic substrate back side, SMT components and parts soldering is in covering copper Al2o3ceramic substrate front; Described dual inline type hermetically metal sealing enclosure is provided with cavity, is filled with inert gas in cavity, and dual inline type hermetically metal sealing enclosure bottom is provided with pin; Describedly cover copper Al2o3ceramic substrate is provided with inverse-excitation type without optocoupler DC/DC circuit.
Describedly cover copper Al2o3the existing Al of ceramic substrate2o3the high-termal conductivity of pottery, high compressive strength, high-insulativity, low thermal resistance, the matched coefficients of thermal expansion good with metal air-tight seal casing, have again the high current carrying capacity of copper conductor, the simplicity of showing methods.
Described dual inline type metal air-tight seal casing, to be dual-in-line draw from housing bottom surface pin, is suitable for plug-in type and installs, and provide I/O/function to control pin for internal circuit; With cover copper Al2o3ceramic substrate combines, and for inverse-excitation type to provide passage of heat and the insulator interface of low thermal resistance without optocoupler switching circuit, the heat produced that Switching Power Supply consume energy conducts to shell rapidly, thus the junction temperature of reduction device itself; The dual inline type metal air-tight seal casing of inert gas filling provides the environment of a no oxygen and steam for SMT components and parts, reduces oxidation and the impact of corrosion on the SMT components and parts life-span, thus further increases power supply reliability.
Described input filter circuit is used for the ripple in filtering input voltage and reflected voltage, for other circuit part provides smooth voltage, for transformer provides switching energy.
Described reference circuit integrated circuit (IC) chip N1 internal logic circuit, control circuit provide a high-precision voltage reference.
Described soft start and overvoltage/undervoltage circuit provide high-precision reference voltage base for internal circuit, and carry out thresholding judgement to input voltage amplitude, after input voltage value reaches the amplitude of setting, open other circuit working by soft starting circuit.
Described former limit feedback current compensates and the output voltage zero crossing of temperature-compensation circuit to transformer T1 feedback carries out sampling rate comparatively, and can be controlled modulating frequency and width and drive circuit by the outside resistance adjusted by three.
Described modulating frequency and width and drive circuit, by conversion driving frequency and ON time length, make output voltage meet the requirement of setting.
Described current limit circuit turns off drive circuit when there is power output overload or output short-circuit, injury-free with protection power source.
Be transformed into level and smooth direct voltage output after the ac square wave rectifying and wave-filtering that transformer T1 exports by described output rectifier and filter, thus reach the object of DC-DC power conversion.
Further, 27.1 × 27.1 × 8 dual inline type parallel seam welding metal shells with 6 pins selected by described dual inline type metal air-tight seal casing.
Further, described inverse-excitation type without optocoupler DC/DC circuit comprise input filter circuit C1, reference circuit, soft start and overvoltage/undervoltage circuit, former limit feedback current compensate and temperature-compensation circuit, modulating frequency and width and drive circuit, current limit circuit, power delivery, output rectifier and filter.
Further, described reference circuit, soft start and overvoltage/undervoltage circuit, former limit feedback current compensates and temperature-compensation circuit, modulating frequency and width and drive circuit, current limit circuit are integrated in proprietary integrated circuit (IC) chip N1.
The beneficial effect that the present invention compared with prior art has is:
(1) reliability improves: without photoelectrical coupler in power supply, also the high temperature failure pattern just do not brought therefrom and time failure mode, reliability index is greatly improved, simultaneously, owing to decreasing SMT component number, also indirectly improve reliability index;
(2) circuit is simple: owing to not using photoelectrical coupler or pulse isolation transformer, therefore the circuit such as secondary benchmark, sampling, amplification (driving) are also eliminated, not only decrease components and parts, also reduce fabric swatch difficulty and requirement equally;
(3) volume is little, lightweight: under equal power output and efficiency, use component size the same terms, and the DC/DC power supply made by the present invention reduces about 1/4th on volume, weight reduces about 1/5th.
Accompanying drawing explanation
Fig. 1 is vertical view of the present invention;
Fig. 2 is end view of the present invention;
Fig. 3 is that inverse-excitation type of the present invention is without optocoupler DC/DC circuit connecting relation figure.
Number in the figure is: 1-covers copper Al2o3ceramic substrate, 2-SMT components and parts, 3-dual inline type metal air-tight seal casing, 4-inert gas, 5-pin.
Embodiment
In order to make object of the present invention, technical scheme and advantage clearly understand, below in conjunction with drawings and Examples, the present invention is further elaborated.Should be appreciated that specific embodiment described herein only in order to explain the present invention, be not intended to limit the present invention.
See figures.1.and.2 known, inverse-excitation type, without optocoupler thick film DC/DC Switching Power Supply, comprises and covers copper Al2o3ceramic substrate 1, SMT components and parts 2, dual inline type metal air-tight seal casing 3, described dual inline type metal air-tight seal casing 3 soldering is in covering copper Al2o3ceramic substrate 1 back side, SMT components and parts 2 soldering is in covering copper Al2o3ceramic substrate 1 front, described dual inline type metal air-tight seal casing 3 inside is provided with cavity, inert gas 4 is filled with in cavity, dual inline type metal air-tight seal casing 3 bottom surface is provided with pin 5, in this programme, 27.1 × 27.1 × 8 dual inline type parallel seam welding metal shells with 6 pins 5 selected by dual inline type metal air-tight seal casing 3, in described pin 5, the first pin (No.1) is just being defined as input voltage, crus secunda (No.2) is defined as input ground, tripod (No.3) is defined as shell ground, 4th pin (No.4) is just being defined as output voltage, 5th pin (No.5) is defined as and exports ground, 6th pin (No.6) is defined as output and forbids end, describedly cover copper Al2o3ceramic substrate 1 is provided with inverse-excitation type without optocoupler DC/DC circuit (not marking in figure).
Describedly cover copper Al2o3the existing Al of ceramic substrate 12o3the high-termal conductivity of pottery, high compressive strength, high-insulativity, low thermal resistance, the matched coefficients of thermal expansion good with metal air-tight seal casing, have again the high current carrying capacity of copper conductor, the simplicity of showing methods.
Described dual inline type metal air-tight seal casing 3, pin 5 is drawn from housing bottom surface in dual-in-line, is suitable for plug-in type and installs, and provides I/O/function to control pin for internal circuit; With cover copper Al2o3ceramic substrate 1 combines, and for inverse-excitation type to provide passage of heat and the insulator interface of low thermal resistance without optocoupler switching circuit, the heat produced that Switching Power Supply consumed energy conducts to shell rapidly, thus reduces the junction temperature of device itself; The dual inline type metal air-tight seal casing 1 of inert gas 4 filling provides the environment of a no oxygen and steam for SMT components and parts 2, reduces oxidation and the impact of corrosion on SMT components and parts 2 life-span, thus further increases power supply reliability.
With reference to known shown in Fig. 3, described inverse-excitation type comprises input filter circuit C1, reference circuit, soft start and overvoltage/undervoltage circuit without optocoupler DC/DC circuit, former limit feedback current compensates and temperature-compensation circuit, modulating frequency and width and drive circuit, current limit circuit, power delivery, output rectifier and filter; Described reference circuit, soft start and overvoltage/undervoltage circuit, former limit feedback current compensate and temperature-compensation circuit, modulating frequency and width and drive circuit, current limit circuit are integrated in proprietary integrated circuit (IC) chip N1.
Described input filter circuit C1 is used for the ripple current in filtering input voltage and transformer reflected voltage, to reach level and smooth input voltage and to provide energy storage for power delivery.
Described reference circuit is integrated circuit (IC) chip N1 internal logic circuit, control circuit provides a high-precision voltage reference.
Described soft starting circuit is after power circuit is connected, the upper charging voltage of C3 control modulating frequency and width and drive circuit output, that is to say that output voltage progressively raises along with the rising of voltage on C3 and finally reaches rated output voltage, soft-start time is determined by the capacitance of C3.
The resitstance voltage divider that described overvoltage/undervoltage circuit is made up of R1, R2 and the inner thresholding comparison circuit of integrated circuit (IC) chip N1 are formed; When the input voltage partial pressure value arrival threshold voltage on R2, comparator overturn and open integrated circuit (IC) chip N1 other control circuit inner.
The feedback current compensation of described former limit and temperature-compensation circuit are after soft starting circuit and overvoltage/undervoltage circuit normally work, modulating frequency and width and drive circuit driving power metal-oxide-semiconductor V1 conducting, R6, R7 electrical resistance collection metal-oxide-semiconductor V1 drain electrode zero crossing waveform (the feedback waveform of transformer T1 when output current clear point) comes time and the pulsewidth of control switch conducting, thus reaches the effect controlling output voltage.The temperature-compensation circuit of R5 and integrated circuit (IC) chip N1 inside is for compensating the temperature coefficient effect exporting rectifier diode V2;
Described power delivery is realized by transformer T1, power MOS pipe V1.In fact, transformer T1 is a pair closely-coupled isolation energy storage inductor, completes input energy storage respectively and exports energy release process; Metal-oxide-semiconductor V1 completes the switching process of energy storage and release.The size of R3 resistance determines the height of switching energy.
Described output rectification circuit is made up of rectifier diode V2 and filter capacitor C5, wherein electric capacity C5 not only as exporting energy holding capacitor, but also as output current ripple filter capacitor.
In sum, resistance R1, R2 determines input voltage unlatching value; Electric capacity C3 determines to open rear output voltage settling time; Resistance R6, R7 and transformer T1 primary and secondary turn ratio determination output voltage rated value; Resistance R5 compensates the temperature coefficient effect exporting rectifier diode; Resistance R3 determines power output.
The foregoing is only preferred embodiment of the present invention, not in order to limit the present invention, all any amendments done within the spirit and principles in the present invention, equivalent replacement and improvement etc., all should be included within protection scope of the present invention.