CN106208646A

CN106208646A - A kind of directly filtering type Switching Power Supply

Info

Publication number: CN106208646A
Application number: CN201610639666.0A
Authority: CN
Inventors: 王保均
Original assignee: Mornsun Guangzhou Science and Technology Ltd
Current assignee: Mornsun Guangzhou Science and Technology Ltd
Priority date: 2016-08-05
Filing date: 2016-08-05
Publication date: 2016-12-07
Anticipated expiration: 2036-08-05
Also published as: CN106208646B; WO2018024037A1

Abstract

A kind of directly filtering type Switching Power Supply, for including the occasion of Rectified alternating current, including filter circuit 200, main power stage 300, and indicating circuit 400,400 include terminal 1,2, resistance R1, electric capacity C1, diode D1 and LED, in parallel with R1 again after LED and D1 reverse parallel connection, then connect with C1；400 is in parallel with filtering electrolysis CL, and the capacity of C1 is little, the big ripple of power frequency frequency multiplication that rectification causes, minimum by the electric current of C1, and the pressure drop produced on R1 is not enough to light LED；ESR rise along with CL, the pressure drop that high-frequency excitation electric current produces on ESR synchronizes to raise, the high frequency ripple voltage formed increases, C1 has the effect of logical high frequency, when high frequency ripple voltage on ESR arrives certain threshold values, lighting LED and luminous, the resistance of regulation R1 can regulate the size of threshold values.Thus remind the ESR of user electrolysis CL to have gone up, there is failure risk in Switching Power Supply, this circuit cost is low, it is easy to implement, and does not use inductance detection.

Description

A kind of directly filtering type Switching Power Supply

Technical field

The present invention relates to field of switch power, be transformed to the switch electricity of direct current particularly to the AC or DC of high reliability Source.

Background technology

At present, Switching Power Supply application is very wide, for input power at below 75W, to power factor (PF, Power Factor, also referred to as power factor (PF)) occasion that is not required, inverse-excitation type (Fly-back) Switching Power Supply has charming advantage: electricity Road topology is simple, wide input voltage range.Owing to element is few, the reliability of circuit is the highest, so application is the widest.For side Just, a lot of documents are also referred to as reverse exciting switching voltage regulator, flyback sourse, and Japan and Taiwan are also known as flyback changer.Common Topology is as it is shown in figure 1, this figure prototype is from " the switch that the written book number of doctor Zhang Xingzhu is ISBN978-7-5083-9015-4 Power converter topology and design " page 60, this book referred to herein simply as: list of references 1.By rectifier bridge 101, filtering Circuit 200 and basic flyback topologies element circuit 300 form, and 300 are also referred to as main power stage, and practical circuit is in rectification Also added with protection circuits such as varistor, NTC thermistor, EMI (Electromagnetic Interference) before bridge, with Guarantee that the Electro Magnetic Compatibility of flyback sourse reaches to use requirement.

Rectifier bridge 101 is typically made up of four commutation diodes, the mandate invention description of application number 201210056555.9 Fig. 4-1 in book, Fig. 4-2, Fig. 4-3 give several known technique of painting of rectifier bridge；Filter circuit 200 is typically by electrolysis CL structure Becoming, for convenience, " electrochemical capacitor " is the most all referred to as " electrolysis "；In order to EMI performance is outstanding, typically at electrolysis CL two ends also The high pressure low volume electric capacity that a meeting high frequency characteristics in parallel is good；Main power stage 300 includes a lot of device, the most only lists power and becomes Depressor B, master power switch pipe V, generally metal-oxide-semiconductor, export commutation diode D, output filter capacitor C, the merit in flyback topologies Rate transformator B is in fact energy storage inductor, and main power stage 300 the most also includes a lot of circuit, as being used for absorbing metal-oxide-semiconductor negative peak electricity The DCR circuit of pressure, pwm control circuit, opto-coupled feedback circuit, even active clamp circuit, its main topology is not limited to flyback electricity Road, can be double-transistor flyback circuit, half-bridge converter etc..

Along with the rise of direct current supply, such as solar energy, wind power plant are popularized, HVDC is powered and is also begun to popularize, Also occur in that employing flyback sourse, as the standby power etc. of system, in the basic topology of Fig. 1, has removed rectifier bridge 101, Ji Keshi Existing direct current supply, also someone likes directly using direct current supply from the front end of rectifier bridge 101, and such efficiency is lower slightly, but can realize AC/DC, and both positive and negative polarity when need not distinguish direct current supply.

Domestic a lot of producer does not carry out national standard in real earnest, and some input powers application more than 75W, such as platform The power supply of formula computer, power is more than 150W, is also the topology using similar Fig. 1, and the employing of main power stage more than 300 is two-tube just Swashing, double tube positive exciting is the popular saying of industry, is actually half-bridge converter；Even without sealing in power factor in rectifier bridge 101 After correction inductance, i.e. rectifying and wave-filtering, power to half-bridge converter.Main power stage 300 also has employing single tube normal shock, asymmetrical half-bridge Realize.

Rectifier bridge 101 seals in PFC inductance, still belongs to passive filtering formula PFC, be not active merit Rate factor correcting.We are the Switching Power Supply of rectification post filtering, and rectifier bridge seals in PFC inductance, then filter Switching Power Supply is all defined as: directly filtering type Switching Power Supply.

Filter circuit 200 is typically made up of electrochemical capacitor CL, along with the popularization of intellectualizing system in industrial circle, makes electricity consumption The weak point of the Switching Power Supply solved embodies the most therewith, because employing electrolysis CL, and the most therefore the characteristic of this electrolysis limits Having made the purposes of Switching Power Supply, the electrolysis life-span under high temperature and low temperature is always an industry difficult problem, it is well known that electric capacity CL is frequent For the electrolysis that 400V is pressure, and the pressure electrolysis more than 250V, its low temperature typically can only work-25 DEG C.I.e. at the ring of-40 DEG C Under border, such as the countries and regions of three provinces in the northeast of China, Xinjiang and high latitude, the use of Switching Power Supply becomes thorny, of course, it is possible to Use CBB thin-film capacitor such as to filter, but volume is excessive, and high cost.

The capacitance of electrolysis unit volume is very big, so in the Switching Power Supply including flyback sourse, particularly exchanging The field of input, is still the solution of low cost at present, applies the most in various power supplys, such as various charger for mobile phone, pen Remember this computer adapter, the power supply of various colour TV, desktop computer power supply, the standby power etc. of air-conditioning, Switching Power Supply will be used, Also using electrolysis simultaneously.

During one Switching Power Supply of design, often face the life problems of electrolysis CL, in actual use, a lot of Switching Power Supplies Not reaching service life, its main cause is exactly the electrolysis premature failure filtered.The occasion that a lot of requirements are higher, have employed redundancy and sets Meter, uses two Switching Power Supplies to backup each other, is broken one, it is also possible to normally work.Relatively costly, and still do not know wherein Switching Power Supply is when to lose efficacy, and is also inconvenient to prepare spare unit.

Common nonredundancy design occasion, once Switching Power Supply lost efficacy, it will cause a lot of related inefficacy, so that damage Losing extended, according to statistics, the Switching Power Supply of qualified design lost efficacy, and more than 97% was lost efficacy in advance by the electrolysis filtered causes.

Existing most Switching Power Supply using electrolysis, still can not carry out effectively informing in advance to the inefficacy of electrolysis. In the existing patent application " a kind of directly filtering type Switching Power Supply " of the application number 201610040060.5 of inventor, provide one Planting solution: seal in indicating circuit in the direct current power supply loop of electrolysis CL, indicating circuit is in parallel by luminescence unit and inductance L Composition, it is ensured that direct current supply is contrary with the conducting direction of luminescence unit by the sense of current of inductance L, when being electrolysed CL and being normal, The exciting curent of switching tube V is substantially not present in inductance L, and LED is the most luminous；When the ESR rise of electric capacity CL is bigger, V swashs Magnetoelectricity flows out in present L, and when V turns off, the exciting curent flowing through L cannot suddenly change, and through luminous organ LED afterflow, simultaneously drives LED is luminous, so reminds user: the ESR of the electrolysis CL of Switching Power Supply has gone up, and there is the risk of inefficacy, it is to avoid damage The expansion lost, has low cost, efficiency is constant, implement easy feature.For convenience, this patent application 201610040060.5 The most existing patent A.

Existing patent A employs inductance L, and this inductance L is alternating current to be born or the crest voltage of direct current input when opening machine, And to the pressure height of the big charging current charged several times, i.e. this inductance before filtering electrolysis CL, the impact operating current that bears Requiring very big, its cost is comparatively speaking, the lowest.

Simultaneously in the power frequency charge circuit of this circuit electrolytic capacitor filter to be series at, original circuit to be changed Dynamic.

Summary of the invention

In view of this, the invention solves the problems that what the direct filtering type Switching Power Supply that existing use electrochemical capacitor filters existed Not enough, it is provided that a kind of directly filtering type Switching Power Supply, do not use the inductance that pressure height, electric current are big, do not change original circuit, Before electrolytic capacitor filter complete failure, it is provided that instruction, it is achieved informing in advance before Switching Power Supply complete failure.

The object of the present invention is achieved like this, and a kind of directly filtering type Switching Power Supply, for including Rectified alternating current Direct current inputs, including filter circuit, and main power stage, also include that an indicating circuit with two terminals, direct current input connect Filter circuit, filter circuit and main power stage are in parallel, at least include the electrolysis in parallel with a main power stage electricity in filter circuit Hold, it is characterized in that: indicating circuit is in parallel with electrochemical capacitor.

Preferably, indicating circuit scheme one includes the first resistance, the first electric capacity, the first diode and the first light-emitting diodes Pipe, the first resistance and the first diode and these three the device parallel connections of the first light emitting diode, wherein the first light emitting diode and First diode reverse is in parallel, and the two-terminal network formed after parallel connection is referred to as parallel network, and the terminal of parallel network is with first The anode of diode, the negative electrode of the first diode make a distinction, parallel network again with the first capacitances in series, and form a series connection Two-terminal network, the two-terminal network of described series connection is referred to as series network, and two terminals of series network are respectively One terminal, the second terminal.

Preferably, indicating circuit scheme two includes the first resistance, the second resistance；First electric capacity, the second electric capacity；One or two pole Pipe and the second diode and the first light emitting diode；Its annexation is: the second resistance and the series connection of the first light emitting diode, Form the first network with two-terminal, first network and the second electric capacity and the first resistance the most in parallel, formed and there is two-terminal The second network, the second network again with the second Diode series, formed and there is the 3rd network of two-terminal, the feature of the 3rd network It is that the second diode and the first light emitting diode are in the same direction；3rd network and the first diode reverse are in parallel, are formed and have two ends Son the 4th network, the 4th network again with the first capacitances in series, and formed one series connection two-terminal network, described series connection Two-terminal network is referred to as series network, and two terminals of series network are respectively the first terminal, the second terminal.

Operation principle will in conjunction with the embodiments, is set forth in.

The invention have the benefit that

Cost is lower than the prior art using inductance, and the indicating circuit loss set up is low, the normal work to former changer Conversion efficiency have little to no effect, wiring is simple, volume is little, easy to use, realizes equally: before electrochemical capacitor lost efficacy, should Light emitting diode in display lamp lumination of light emitting diode or optocoupler has electric current to flow through, and optocoupler exports the signal of an isolation to carry Show user or other circuit.

Accompanying drawing explanation

Fig. 1 is the existing inverse-excitation type switch power-supply schematic diagram for AC-DC；

Fig. 2 is the schematic diagram of the direct filtering type Switching Power Supply of the first embodiment using indicating circuit scheme one, is also The schematic diagram of the second embodiment；

Fig. 3 is U in first embodiment_DCThe direct current input path schematic diagram to the charging current that electrochemical capacitor produces；

Fig. 4 is main power stage switching tube driving voltage and exciting curent sequential chart in first embodiment；

Fig. 5 is electrochemical capacitor exciting curent i of main power stage time normal in first embodiment_MPath schematic diagram；

Fig. 6 is the equivalent circuit diagram that the exciting curent of the main power stage of Fig. 5 is relevant；

Fig. 7-1 is embodiment one schematic diagram of indicating circuit scheme one correspondence of the present invention；

Fig. 7-2 is embodiment two schematic diagram of indicating circuit scheme one correspondence of the present invention；

Fig. 7-3 is embodiment three schematic diagram of indicating circuit scheme one correspondence of the present invention；

Fig. 7-4 is embodiment four schematic diagram of indicating circuit scheme one correspondence of the present invention；

Fig. 7-5 is embodiment five schematic diagram of indicating circuit scheme one correspondence of the present invention；

Fig. 7-6 is embodiment six schematic diagram of indicating circuit scheme one correspondence of the present invention；

Fig. 8 is the schematic diagram of the direct filtering type Switching Power Supply of the second embodiment using indicating circuit scheme two；

Fig. 8-1 is embodiment one schematic diagram of indicating circuit scheme two correspondence of the present invention；

Fig. 8-2 is embodiment two schematic diagram of indicating circuit scheme two correspondence of the present invention；

Fig. 8-3 is embodiment three schematic diagram of indicating circuit scheme two correspondence of the present invention；

Fig. 8-4 is embodiment four schematic diagram of indicating circuit scheme two correspondence of the present invention；

Fig. 9 is the schematic diagram of the direct filtering type Switching Power Supply of the 3rd embodiment.

Detailed description of the invention

First embodiment

Fig. 2 shows the schematic diagram of the direct filtering type Switching Power Supply of first embodiment of the invention, is used for including that pulsation is straight The direct current input of stream electricity, direct current inputs with U_DCIllustrate, including filter circuit 200, main power stage 300, also include that one has two The indicating circuit 400 of individual terminal, direct current input U_DCConnect filter circuit 200, filter circuit 200 and main power stage 300 in parallel, filter Wave circuit 200 at least includes an electrolysis CL in parallel with main power stage, it is characterized in that: indicating circuit 400 is with electrolysis CL also Connection, indicating circuit 400 at least includes the first resistance R1, the first electric capacity C1, the first diode D1 and the first LED.

Rectified alternating current: see Fig. 1, alternating current is after rectifier bridge 101, if not having filter circuit, then, frequency will be obtained Rate is the Rectified alternating current of two times of alternating current, and in background technology, application number 201210056555.9 is discussed in detail.

Scheme one: the first resistance R1 of indicating circuit, the first electric capacity C1, the first diode D1 and the first light emitting diode LED, the first resistance R1 and the first diode D1 and these three the device parallel connections of the first LED, wherein first is luminous Diode (LED) and the first diode D1 reverse parallel connection, the two-terminal network formed after parallel connection is referred to as parallel network 24, parallel-connection network The terminal of network 24 makes a distinction with anode, the negative electrode of the first diode D1 of the first diode D1, and parallel network 24 is again with first Electric capacity C1 connects, and forms the two-terminal network of a series connection, and the two-terminal network of described series connection is referred to as series network, just Being indicating circuit 400, two terminals of series network 400 are respectively the first terminal the 1, second terminal 2, and this series network 400 is also It it is the function body of the direct filtering type Switching Power Supply of the present invention.

First electric capacity C1 hereinafter referred to as C1, the first resistance R1 hereinafter referred to as R1, letter below the first LED Being referred to as LED, other device is similar.

LED uses Φ 3mm red highlighted, and for convenience, light emitting diode is referred to as luminous tube, and model is 3AR2UD, Electric capacity C1 is the patch capacitor of 333/500V, nominal capacity be 0.033uF, D1 be 1N4148, R1 be the Chip-R of 22K, press Fig. 2 forms direct filtering type Switching Power Supply, and Switching Power Supply employs 25W flyback sourse, and model is the LH25-of applicant company The semi-finished product of the non-embedding of 10B12, its filtering electrolysis is 47uF/400V, and for domestic quality capacitance, rectifier bridge is four 1N4007 Composition, operating frequency is 65KHz, and under 220VAC inputs, fully loaded maximum duty cycle is 0.24.

It is to be noted that Fig. 2 indicating circuit 400 is directly in parallel with electrolysis CL in Switching Power Supply, forward is in parallel or reverse the most also Connection can, forward is in parallel: i.e. terminal 1 connects the positive pole of electrolytic capacitor filter, and terminal 2 connects the negative pole of electrolytic capacitor filter； Or reverse parallel connection: terminal 1 connects the negative pole of electrolytic capacitor filter, and terminal 2 connects the positive pole of electrolytic capacitor filter.Hereafter can be special Explanation.

When first embodiment is solded into forward parallel way, each side index of actual measurement flyback sourse, all with phase before With, particularly conversion efficiency, there is no appearance it is observed that decline, and luminous tube LED is the most luminous.

In order to verify that the present invention can work, inventor have employed method pioneering before and tests the first enforcement Example:

Electrochemical capacitor owing to losing efficacy is difficult to find, and in above-mentioned filtering electrochemical capacitor, seals in adjustable resistance, carrys out mould Intending the electrochemical capacitor that performance has declined, adjustable resistance adjustable extent here is 0-39 Ω, when the resistance of adjustable resistance When being transferred to 5 Ω, be equivalent to the ESR of electrochemical capacitor of 47uF/400V about 0.5 Ω when non-defective unit and have risen to 5.5 Ω, electrolysis The performance of electric capacity is close to non-serviceable edge.

Now, the luminous tube LED in Fig. 2 is luminous, and the meansigma methods actual measurement of operating current is 1.6mA.

By choosing the electric capacity C1 of different capabilities, the sensitivity of preliminary regulation instruction, the capacity of electric capacity C1 is little, sensitivity Low；The capacity of electric capacity C1 is big, highly sensitive.Owing to luminous tube is when luminescence, there is the forward voltage drop of 1.6V to 2.2V, Ke Yi Luminous tube LED two ends parallel resistance R1 regulates sensitivity, and as in this example, R1 is according to the resistance of 1.6K, then, below 1mA The voltage that produces at R1 two ends of peak point current at below 1.6V, at this moment luminous tube LED is the most luminous.

Note: the conduction voltage drop of white-light emitting pipe is about 3.0V, red is the most different from green, and sending out within optocoupler Light device conduction voltage drop is about 1.1V.

Operation principle: see Fig. 3, when electrochemical capacitor is normal, then its ESR is 0.5 Ω, filtering electrolysis CL two ends Ripple voltage has two kinds, when Switching Power Supply is fully loaded with work as a example by explanation.

When being electrolysed CL and being normal, U_DCFour diodes in the rectifier bridge 101 of front end, only close when the alternating current of input Two diodes within rectifier bridge are just simultaneously turned on, to electrolysis CL electric energy supplement, the charged electrical that rectifier bridge 101 produces during peak Fig. 3 is seen in the path of stream, and during this, the frequency of charging current is 2 times of civil power, for 100Hz or 120Hz, due to C1 capacity Less, for 0.033uF, compare the 47uF of CL, the charging current in C1 is only 7/10000ths of CL, the peak value of the charging current of CL For 2.39A, then, the charging current flowing through D1 is only 1.67mA, and at this moment, LED is the most luminous because of reverse-biased.

Before next charge cycle arrives, main power stage to be discharged by CL always, and CL terminal voltage is declining always, directly Again charging up after 10mS or 8.33mS, the two ends of such CL form the low-frequency ripple of 2 times that is mains frequency, its Peak-to-peak value is at about 20V.When the capacity of C1 is sufficiently large, this low-frequency ripple can form enough electric currents in C1 to be come Bright LED, so, it is to be ensured that the electric current that low-frequency ripple is formed in C1, the pressure drop formed at the two ends of resistance R1 is led less than LED's Logical pressure drop.If U_DCFor lasting direct current, then, low-frequency ripple is lighted this problem of LED and be there will be no.

The electric capacity of the 0.033uF alternating low frequency ripple to 100Hz, its impedance is about 48K Ω, and peak-to-peak value is at about 20V The virtual value of low frequency triangle ripple be about 10V, then, the low-frequency ripple electric current flowing through C1 is about 0.20mA, and peak value is 0.40mA, R1 are 22K, and its pressure drop should be 8.8V, it is true that LED does not has luminescence yet, reason: see Fig. 3, CL is charged by civil power Time, there is a charging current synchronized to flow through D1, and when the terminal voltage of CL declines, CL is discharged by C1, forms discharge current, fills The electricity time is short, and discharge time is the longest, and charging typically completes in 1mS, and discharge time is close to a charge cycle, close (10mS-1mS)=9mS, owing to the persistent period is long, the peak point current in this time is extremely low.CL is discharged by C1, and approach is: C1 The negative electrode of negative pole → D1 of positive pole → CL of upper end → CL, i.e. the upper end of lower end → R1 of R1, i.e. D1 anode → C1 under End；Integration that CL is discharged by C1 and integration C1 charged equal to civil power, and the time discharged is long, electric current is nearly constant, so Its electric current is little, and this electric current is through the two ends of R1, and the pressure drop of generation is the lowest.

Choosing of R1 resistance, it is to be ensured that when low-frequency ripple electric current is by C1, LED is the most luminous, a least skill: When CL is charged by rectifier bridge 101, this charging current directly flows through D1, and does not flow through LED, it is ensured that LED is the most luminous.If terminal 1 negative pole connecting electrolytic capacitor filter, terminal 2 connects the positive pole of electrolytic capacitor filter, and when CL is charged by rectifier bridge 101, LED is just Can be luminous, circuit is unsuccessful, and the value of R1 to be adjusted the most permissible.

When being electrolysed CL and being normal, the electrochemical capacitor of 47uF/400V described above, its ESR under 65KHz is 0.5 Ω, i.e. When switching tube V normally works, the exciting curent i of main power stage_MAs shown in Figure 4, wherein, Ugs is grid and the source electrode of switching tube V Driving voltage, exciting curent i_MPath see Fig. 5.

When rectifier bridge 101 is not turned on, electrolysis CL and C1 is equal to main power stage to the discharge current of main power stage Exciting curent i_M.Note, C1, because the little discharge current to main power stage of capacity is the least, can ignore here.CL is at 65KHz in electrolysis Switching frequency under capacitive reactance be 1/ (2 π fC), calculate as 52m Ω, much smaller than its ESR, under 65KHz, ESR rises mainly Effect；Waveform shown in Fig. 4 is not sinusoidal wave, and its first-harmonic is sinusoidal wave, and its harmonic frequency is all high than 65KHz, so here Simply estimation.

The operating frequency of 25W flyback power stage 300 is 65KHz, and under 220VAC inputs, fully loaded maximum duty cycle is 0.24.The exciting curent i of main power stage 300_MMeansigma methods when switching tube V turns on is about 408mA, and peak value is about 816mA, this The pressure drop that individual electric current is formed on the ESR of CL, sees Fig. 6, for U=IR=0.816 × 0.5=0.408V.The most in figure 6, end There is the high frequency ripple of a fluctuation between son 1 and 2, its waveform shape is with i in Fig. 4_MWaveform, it is clear that the peak value of 0.408V is not Be sufficient for LED conducting and luminous.

About 0.5 Ω when the ESR of electrolysis CL is from non-defective unit has risen to 5.5 Ω, i.e. electrolysis CL is close to inefficacy edge. i_MAs when switching tube V turns on, peak value is about 816mA, the pressure drop that this electric current is formed on the ESR of CL, see Fig. 6, for U= IR=0.816 × 5.5=4.48V.The most in figure 6, there is the high frequency ripple of a fluctuation, its waveform shape between terminal 1 and 2 With i in Fig. 4_MWaveform, it is clear that the peak value of 4.48V be sufficient for LED conducting and luminous.

C1 is 0.033uF, and its capacity is less, but under the frequency of 65KHz, its capacitive reactance is 73.8 Ω, can be that LED provides Enough operating currents and luminous, and rise metering function, regulate its capacity and can obtain different operating currents.

The operation principle of the present invention not very complexity, the capacity of C1 is little, and C1 has logical high frequency, the effect of resistance low frequency；Rectified current The big ripple of power frequency that pass rises is minimum by the electric current of C1, and the pressure drop produced on resistance R1 is not enough to light LED, and along with electricity Solving the ESR rise of CL, the pressure drop that the high-frequency excitation electric current of Switching Power Supply of the present invention produces on ESR synchronizes to raise, the height of formation Frequently ripple voltage raises along with the aging of electrochemical capacitor, and C1 has the effect of logical high frequency, and the high frequency ripple voltage on ESR arrives During certain threshold values, can light LED and luminous, the resistance of regulation R1 can regulate the size of threshold values, i.e. high frequency ripple voltage and lead to Crossing pressure drop that the electric current of electric capacity C1 the formed conducting voltage less than LED at R1 two ends, LED is not turned on, and LED also cannot shunt for R1 Thus it is the most luminous.

The obtaining value method of C1: the power frequency 2 of civil power is up to 120Hz again, the operating frequency of current Switching Power Supply is typically can Listen outside audio frequency, for 22KHz, then, the ratio of frequency is (22000/120)=183.3 times, and the value of C1 is at monitored electricity Solve less than 1/the 183.3 of CL.If CL is 47uF, then C1 should at (47uF/183.3)=below 0.256uF, due to The nominal value of electric capacity, by series values such as E-3, E-6, E-12, can take below 0.24uF here.

So driven for emitting lights pipe LED luminescence realizes goal of the invention, reminds user: the ESR of this electrolysis CL has risen to Focus, in order to user determines next step measure.In this example, the load of direct filtering type Switching Power Supply is down to 30%, LED is the most luminous, and operating current is down to 0.36mA, and the luminous tube using high brightness is the most eye-catching.

Now, electrochemical capacitor remains to work, but owing to the exciting curent of main power stage exists bigger caloric value on ESR, Being 0.22W in this example, this electrochemical capacitor has been under golf calorific value, in accelerating aging, generally, and can be little tens In hundreds of hour, ESR rapid increase, cause heating to strengthen further, until losing efficacy, capacity is lost, thus causes as opened Close a series of inefficacies such as pipe demolition.

C1 and parallel network 24 series connection explanation: C1 and parallel network 24 are connected, owing to being series loop, merit after transposition Can be identical, so the series system that the case one of indicating circuit includes has multiple, but function is the most identical, as following:

A the negative electrode of () D1 is downward, on top, as shown in Fig. 7-1 of 400 or independent in Fig. 2, the anode of D1 is even for C1 Connecing one end of C1, the other end of C1 is the first terminal 1 of indicating circuit, and the negative electrode of D1 is the first terminal 2 of indicating circuit；

B the negative electrode of () D1 is downward, C1 is below, and as shown in Fig. 7-2, the negative electrode of D1 connects one end of C1, and the anode of D1 is The first terminal 1 of indicating circuit, the other end of C1 is the second terminal 2 of indicating circuit；

C upwards, on top, as shown in Fig. 7-3, the negative electrode of D1 connects one end of C1, the other end of C1 to C1 to the negative electrode of () D1 Terminal 1 for indicating circuit；The anode of D1 is the terminal 2 of indicating circuit；It is true that this mode with the Fig. 7-2 of above-mentioned (b) is Identical, the terminal of (b) mode 1 equal to the terminal 2 of (c), the terminal 2 of (b) mode equal to the terminal 1 of (c), i.e. Fig. 7- The terminal 1 and 2 of 3 exchanges, the most identical with (b) of Fig. 7-2；

D upwards, C1 is below, and as shown in Fig. 7-4, the anode of D1 connects one end of C1, the other end of C1 for the negative electrode of () D1 Terminal 2 for indicating circuit；The negative electrode of D1 is the terminal 1 of indicating circuit；It is true that this (a) mode with above-mentioned Fig. 7-1 is Identical, the terminal 1 of (a) mode is equal to the terminal 2 of (d), and the terminal 2 of (a) mode is equal to the terminal 1 of (d), i.e. (d) The 1 of mode and 2 exchange, the most identical with (a) of Fig. 7-1.

I.e. real effective connected mode only has (a) of above-mentioned Fig. 7-1 and (b) mode of Fig. 7-2, electric capacity C1 and network 24 series connection, owing to being series loop, after device transposition, function is identical, and this is known technology, and (b) mode of Fig. 7-2 is exactly C1 and network 24 transposition of (a) mode of Fig. 7-1, the most substantially, (b) mode of (a) of Fig. 7-1 and Fig. 7-2 It is equivalent.The i.e. scheme one of indicating circuit includes above-mentioned four kind connected mode.

It addition, electric capacity C1 can obtain by two capacitances in series, then, the electric capacity C1 of Fig. 7-1, go here and there with electric capacity C1a and C1b Connection substitutes, and just obtains the embodiment of Fig. 7-5, and the circuit of Fig. 7-1 and the circuit of Fig. 7-5 are equivalent.As previously mentioned, string Connection loop, after device transposition, function is identical, further, electric capacity C1b and network 24 transposition, just obtains figure Embodiment shown in 7-6.

The circuit of Fig. 7-2, the circuit of Fig. 7-3, the circuit of Fig. 7-4, the circuit of Fig. 7-5, the circuit of Fig. 7-6 are replaced Fig. 2 Middle indicating circuit 400, can normally work, and the resistance of the R1 in Fig. 7-3 and Fig. 7-4 to take little, and otherwise, rectifier bridge 101 exists The charging current produced during alternating current peaking can light LED.Visible, four circuit of first embodiment can realize invention mesh 's.The circuit of Fig. 7-6 replaces the embodiment that in Fig. 2, indicating circuit 400 obtains, and has its advantage: when the switching frequency ratio of power supply Time higher, respectively the most on top and below, and capacity is the least for electric capacity C1a and C1b, it is possible to achieve light emitting diode and Switching Power Supply Electrical isolation, because the frequency of civil power is low, is easily controlled through the leakage current of electric capacity C1a and C1b and realizes below limit value Safety is up to standard.

In fact in the content of first embodiment, include 6 kinds of embodiments, in order to save length, only with one total " One embodiment " summarize, it is a series embodiment in fact.The electric current flowing through luminous tube LED in first embodiment is not direct current Electricity, but with power stage 300 with high frequency electric frequently, when the lead-in wire of LED is longer, its electromagnetic radiation can not be ignored；Luminous When pipe LED changes the luminous organ in optocoupler into, the output electric current of optocoupler is also periodically to occur, is not a stable signal, this Trouble can be caused to follow-up circuit.Second embodiment shows solution.

Second embodiment

Second embodiment sees the principle that Fig. 8, Fig. 8 show the direct filtering type Switching Power Supply of second embodiment of the invention Figure, for including the direct current input of Rectified alternating current, direct current inputs with U_DCIllustrate, including filter circuit 200, main power stage 300, Also include an indicating circuit 400 with two terminals, direct current input U_DCConnect filter circuit 200, filter circuit 200 and master Power stage 300 is in parallel, at least includes an electrolysis CL in parallel with main power stage, it is characterized in that in filter circuit 200: instruction electricity Road 400 is in parallel with electrolysis CL, and indicating circuit 400 at least includes the first resistance R1, the first electric capacity C1, the first diode D1 and first LED.

Indicating circuit uses scheme two: indicating circuit 400 also includes the second resistance R2, the second electric capacity C2, the second diode D2；If putting together description, it is: indicating circuit 400 includes the first resistance R1, the second resistance R2；First electric capacity C1, the second electricity Hold C2；First diode D1 and the second diode D2 and the first LED；Its annexation is: the second resistance R2 Connect with the first LED, form the first network 21 with two-terminal, for sake of simplicity, the indicating circuit in Fig. 8 400 is independent, sees in Fig. 8-1, and first network 21 is the most in parallel with the second electric capacity C2 and the first resistance R1, is formed and has two Second network 22 of terminal, the second network 22 is connected with the second diode D2 again, forms the 3rd network 23 with two-terminal, the The feature of three networks 23 is, the second diode D2 and the first LED are in the same direction；3rd network 23 and the first diode D1 reverse parallel connection, forms the 4th network 24 with two-terminal, and the 4th network 24 is connected with the first electric capacity C1, and formed one The two-terminal network of series connection, it is simply that indicating circuit 400, the two-terminal network 400 referred to as series network of described series connection, series connection Two terminals of network 400 are respectively the first terminal the 1, second terminal 2, and this series network 400 is also the direct filtering of the present invention The function body of formula Switching Power Supply.

Second diode D2 and the first LED are in the same direction: in the 3rd network 23, it is assumed that R1 opens a way, electric capacity C2 For direct current, be equivalent to open circuit, then, the electric current flowed into from the 3rd network 23 lower end, after LED, then through D2, from 3rd network 23 upper end is flowed out, D2 and LED, all in forward conduction state, this series system, cries in the same direction.D2 and LED locates In forward conduction state, being equivalent to the diode that pressure drop is bigger, its negative electrode is exactly the negative electrode of the 3rd network 23, unidirectional current Stream can flow outwardly from the negative electrode of network, and its anode is exactly the anode of the 3rd network 23, and DC current can be from network Anode flows inward into.

3rd network 23 and the first diode D1 reverse parallel connection, it is simply that refer to: the 3rd network 23 negative electrode connects the anode of D1, the The anode of three networks 23 connects the negative electrode of D1.

Operation principle: see Fig. 8, when being electrolysed CL and being normal, its ESR is 0.5 Ω, and the ripple voltage at electrolysis CL two ends has two Kind: one is the low-frequency ripple of 2 times of mains frequency, and another is that the high-frequency excitation electric current of Switching Power Supply produces on ESR High frequency ripple.

C1 capacity is less, and under the low frequency of 2 times of mains frequency, capacitive reactance is big, and the electric current flowing through C1 is minimum, through D2 rectification After, after C2 filtering, the undertension formed at the two ends of R1 is to light LED.

And along with the ESR rise of electrolysis CL, the pressure drop that the high-frequency excitation electric current of power stage 300 produces on ESR synchronizes to rise Height, the high frequency ripple voltage of formation raises along with the aging of electrolysis CL, and C1 has the effect of logical high frequency, the high frequency stricture of vagina on ESR When wave voltage arrives certain threshold values, after D2 rectification, C2 filtering, the voltage formed at the two ends of R1 be enough to light LED, R2 Play metering function.

So, the electric current flowing through luminous tube LED is pure unidirectional current, and its electromagnetic radiation directly reduces to zero, luminous tube When LED changes the luminous organ in optocoupler into, the output electric current of optocoupler is also the most stable direct current signal, and this can be to follow-up circuit Offer convenience.

Component parameters is: C1 is the patch capacitor of 473/500V, nominal capacity be 0.047uF, C2 be the paster of 104/16V Electric capacity, D1 and D2 be 1N4148, R2 be 1K, R1 be 10K, LED be 3AR2UD.

When the load of Switching Power Supply is 100%, when the ESR rise of electrolysis CL is to 5.5 Ω, the electric current in LED is 0.9mA； The load of direct filtering type Switching Power Supply is down to 30%, and LED is the most luminous, and operating current is down to 0.33mA, uses high brightness Luminous tube is the most eye-catching.So driven for emitting lights pipe LED luminescence realizes goal of the invention, prompting user: the ESR of this electrolysis CL Have risen to focus, in order to user determines next step measure.

Second embodiment also has numerous embodiments, constitutes series of embodiments, and the R2 in network 21 exists with LED strip connection Two kinds of connected modes:

A the negative electrode of () LED is connected with one end of R2, see shown in the network 21 in Fig. 8-1；

B the anode of () LED is connected with one end of R2, see shown in Fig. 8-2；

Both is equivalent.Network 21 is the most in parallel with C2 with R1, forms the network 22 with two-terminal, and network 22 is again Connecting with diode D2, in network 22, it is assumed that R1 opens a way, electric capacity C2, for direct current, is equivalent to open circuit, then network 22 phase When in a diode, having unilateal conduction performance, the negative electrode side of LED is exactly the negative electrode of the second network 22, unidirectional current Stream can flow outwardly from the negative electrode of network, and the anode side of LED is exactly the anode of the 3rd network 23, and DC current is permissible Flow inward into from the anode of network.Owing to being defined to series aiding connection, network 22 and D2 there is also two ways:

A the negative electrode of () network 22 is connected with the sun of D2, see shown in Fig. 8-1；

B the anode of () network 22 is connected with the moon of D2, see shown in Fig. 8-3；

4th network 24 is connected with the first electric capacity C1 again, there is also two ways:

A the D1 anode of () network 24 is connected with C1 one end, see shown in Fig. 8-1；

B the D1 negative electrode of () network 24 is connected with C1 one end, see shown in Fig. 8-2；

In second embodiment, 3 independent series connection in indicating circuit 400, each series connection has two ways, 3 times of totally 2 Side, totally 8 kinds of connected modes, they are equivalent.

It is true that resistance R1 as Fig. 8-4, from original in parallel with C2, change in parallel with D1, realize invention equally Purpose, R1 equally regulates the size of threshold values, owing to having provided technology enlightenment in scheme one, the most no longer comes by technical scheme Carry out rights protection.

The circuit of Fig. 8-2, the circuit of Fig. 8-3, the circuit of Fig. 8-4 are replaced indicating circuit 400 in Fig. 8, can be normal Work, can absorb peak current owing to there is C2, and the charging current that rectifier bridge 101 produces when alternating current peaking will not point Bright LED.The performance of circuit improves further.Visible, four circuit of 8 kinds of modes of the second embodiment can realize invention mesh 's.

Visible, the present invention can solve the problems of the prior art really, with having that less element, cost acquisition are wanted Benefit effect.

Shown in 3rd embodiment, it is power stage 300 and filter circuit 200 all to be changed into other embodiment simultaneously.

3rd embodiment

See the schematic diagram that Fig. 9, Fig. 9 show the direct filtering type Switching Power Supply of third embodiment of the invention, be used for wrapping Including the direct current input of Rectified alternating current, direct current inputs with U_DCIllustrate, including filter circuit 200, main power stage 300, also include one The individual indicating circuit 400 with two terminals, direct current input U_DCConnect filter circuit 200, filter circuit 200 and main power stage 300 is in parallel, at least includes an electrolysis CL in parallel with main power stage, it is characterized in that: indicating circuit 400 in filter circuit 200 In parallel with electrolysis CL, indicating circuit 400 at least includes that the first resistance R1, the first electric capacity C1, the first diode D1 and first are luminous Diode (LED).

Indicating circuit uses scheme one: indicating circuit includes the first resistance R1, the first electric capacity C1, the first diode D1 and the One LED, the first resistance R1 and the first diode D1 and these three the device parallel connections of the first LED, Wherein the first LED and the first diode D1 reverse parallel connection, the two-terminal network formed after parallel connection referred to as parallel connection Network 24, the terminal of parallel network 24 makes a distinction with anode, the negative electrode of the first diode D1 of the first diode D1, parallel-connection network Network 24 is connected with the first electric capacity C1 again, and forms the two-terminal network of a series connection, and the two-terminal network of described series connection is called for short For series network, it is simply that indicating circuit 400, two terminals of series network 400 are respectively the first terminal the 1, second terminal 2, should Series network 400 is also the function body of the direct filtering type Switching Power Supply of the present invention.

Filter circuit 200 and main power stage 300 are in parallel, are careful not to connect instead, it is ensured that main power stage does not connect anti-time in parallel, These are for those skilled in the art, are basic skill.

The main power stage of the present embodiment 300 is half-bridge circuit, in order to adapt to the connected mode of half-bridge circuit, and filter circuit 200 Relatively low pressure electrolysis CL1, CL2 identical by two capacity is in series, and junction point is connected on half-bridge circuit, does not has in figure Draw the equalizing resistance in parallel with electrochemical capacitor；C31 is the coupling electric capacity improving bias magnet properties, and the another side of transformator B is logical Output rectification circuit.

Indicating circuit 400 is in parallel with electrolysis CL, and electrolysis CL is in series for electrolysis CL1, CL2, based on first embodiment Operation principle, the 3rd embodiment realizes goal of the invention equally.

Equally, the circuit of Fig. 7-2, the circuit of Fig. 7-3, the circuit of Fig. 7-4, the circuit of Fig. 7-5, the circuit of Fig. 7-6, figure The circuit of 8-1, the circuit of Fig. 8-2, the circuit of Fig. 8-3, the circuit of Fig. 8-4 replace indicating circuit 400 in Fig. 9, can be normal Work.

Below it is only the preferred embodiment of the present invention, it is noted that it is right that above-mentioned preferred implementation is not construed as The restriction of the present invention.For those skilled in the art, without departing from the spirit and scope of the present invention, also Some improvements and modifications can be made, as by the light emitting diode in the luminous organ in optocoupler, i.e. optocoupler as the first luminescence two Pole is managed；Also sealing in resistance in the first diode, these improvements and modifications also should be regarded as protection scope of the present invention, the most no longer Repeating by embodiment, protection scope of the present invention should be as the criterion with claim limited range.

Claims

1. a direct filtering type Switching Power Supply, for including the direct current input of Rectified alternating current, including filter circuit, main power Level, also includes that an indicating circuit with two terminals, direct current input connect filter circuit, and filter circuit and main power stage are also Connection, at least includes an electrochemical capacitor in parallel with main power stage, it is characterized in that: indicating circuit and electrochemical capacitor in filter circuit In parallel.

Direct filtering type Switching Power Supply the most according to claim 1, it is characterised in that: indicating circuit include the first resistance, First electric capacity, the first diode and the first light emitting diode, the first resistance and the first diode and the first light emitting diode this Three device parallel connections, wherein the first light emitting diode and the first diode reverse are in parallel, the two-terminal network letter formed after parallel connection Being referred to as parallel network, the terminal of parallel network makes a distinction with anode, the negative electrode of the first diode of the first diode, parallel-connection network Network again with the first capacitances in series, and form the two-terminal network of a series connection, the two-terminal network of described series connection referred to as string Networking network, two terminals of series network are respectively the first terminal, the second terminal.

Direct filtering type Switching Power Supply the most according to claim 2, it is characterised in that: also include another electric capacity, another electricity Hold and also connect with parallel network, and another electric capacity and the first electric capacity are connected with two terminals of series network respectively.

Direct filtering type Switching Power Supply the most according to claim 1, it is characterised in that: indicating circuit scheme two includes first Resistance, the second resistance；First electric capacity, the second electric capacity；First diode and the second diode and the first light emitting diode；Its Annexation is: the second resistance and the series connection of the first light emitting diode, is formed and has the first network of two-terminal, first network and the Two electric capacity and the first resistance are the most in parallel, form second network with two-terminal, the second network again with the second Diode series, Forming the 3rd network with two-terminal, the feature of the 3rd network is, the second diode and the first light emitting diode are in the same direction；The Three networks and the first diode reverse are in parallel, form the 4th network with two-terminal, the 4th network again with the first capacitances in series, And forming a two-terminal network connected, the two-terminal network of described series connection is referred to as series network, the two of series network Individual terminal is respectively the first terminal, the second terminal.

Direct filtering type Switching Power Supply the most according to claim 4, it is characterised in that: the first resistance is changed into and the one or two Pole pipe is in parallel.

Direct filtering type Switching Power Supply the most according to claim 4, it is characterised in that: also include another electric capacity, another electricity Hold also with the 4th series network, and another electric capacity and the first electric capacity is connected with two terminals of series network respectively.

7. according to the direct filtering type Switching Power Supply described in any one of claim 2-6, it is characterised in that: the first light emitting diode For the light emitting diode in the luminous organ in optocoupler, i.e. optocoupler.