CN205596013U - Improve circuit of cold -starting ability - Google Patents
Improve circuit of cold -starting ability Download PDFInfo
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- CN205596013U CN205596013U CN201620294862.4U CN201620294862U CN205596013U CN 205596013 U CN205596013 U CN 205596013U CN 201620294862 U CN201620294862 U CN 201620294862U CN 205596013 U CN205596013 U CN 205596013U
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Abstract
The utility model discloses an improve circuit of cold -starting ability, include: rectifier circuit (100), PFC circuit (200), DC DC circuit (300), electrolytic capacitor C1, rectifier diode D1, sequential circuit (600), temperature measurement circuit (400), logic control circuit (500), temperature measurement circuit detection ring border temperature is inputed to logic control circuit, and whether logic control circuit exports logic level decision PFC circuit according to the temperature conditions and work. When product department in normal atmospheric temperature and high temperature lower time, logic control circuit turn -offs the PFC circuit, and the circuit charges for a back level electrolytic capacitor through the diode, and the product can normally be worked, when product department in low temperature lower time, logic control circuit opens the PFC circuit, is stepped up by the PFC circuit and charges for electrolytic capacitor to great improvement is because electrolytic capacitor low temperature characteristics and the poor starting problem that leads to, and its magnetic component and power device etc. Can all select far to be less than conventional specification simultaneously, and can also avoid low temperature under since electrolytic capacitor upward the energy storage less than and the output that leads to is establish the in -process and voltage is appeared and fall.
Description
Technical field
This utility model relates to Switching Power Supply, particularly to the circuit improving Low temperature start-ability of AC-DC Switching Power Supply.
Background technology
Present module switch power supply application conditions becomes increasingly complex, the most a lot of application requirements can use at extremely frigid zones, accordingly, minimum operating ambient temperature is defined into-40 DEG C by many AC-DC Switching Power Supply producer in the industry, but the most most of power supply producer is desirable that client carries out fall volume use at low temperatures.The most at low temperatures, Power supply belt load capacity is deteriorated.
The input rectifying filter circuit of conventional AC-DC Switching Power Supply is as it is shown in figure 1, this circuit at least includes a rectification circuit and an electrochemical capacitor C1, and following stage connects DC-DC circuit；Rectification circuit provides energy to rear class DC-DC circuit after becoming Rectified alternating current, electrochemical capacitor C1 that described Rectified alternating current is stored, filtered AC rectification；The effect of described electrochemical capacitor C1 is most important, because which determining the peak power that DC-DC circuit can provide to successive load.
As in figure 2 it is shown, the pulsating direct current cycle behind commercial power rectification:
In formula 1: tcFor the ON time of bridge rectifier, tHFor the deadline of bridge rectifier, f is mains frequency.Pulsating direct current upper voltage limit on electrochemical capacitor C1:
In formula 2: VRMSFor AC network virtual value.
At tHPeriod, the energy of load consumption is provided by electrochemical capacitor C1 completely, so,
In formula 3: PoFor total output, C1 is the capacitance of changer input electrochemical capacitor C1, and η is the efficiency of DC-DC circuit, VminFor pulsating direct current lower voltage limit.
Can be shown that the pulsating direct current lower voltage limit Vmin on electrochemical capacitor C1 is as follows with the relation of electrochemical capacitor C1 capacitance by formula 1,2,3:
ObviouslyIf taking common frequency power network frequency is 50HZ, then tC< 5ms, t in conventional engineer appliedCTypically take 3ms.
From formula 3, we are it is also seen that total output Po is proportional with the capacitance of electrochemical capacitor C1, and the capacitance of electrochemical capacitor C1 is the biggest, and the most total output Po is the biggest, also imply that electrochemical capacitor C1 can be at t deadline of bridge rectifierHStage provides more energy to DC-DC circuit, and it starts and load capacity is the strongest；The same capacitance that can be seen that pulsating direct current lower voltage limit Vmin and electrochemical capacitor C1 from formula 4 is positively related relation, under the same terms in circuit the capacitance of electrochemical capacitor C1 more hour, pulsating direct current lower voltage limit Vmin also can be the least；
General DC-DC converter all can have the minima requirement of pulsating direct current lower voltage limit Vmin, can be under-voltage and do not work and even damage less than DC-DC circuit after minima, so can be restricted to the minimum capacitance of electrochemical capacitor C1.The most under cryogenic, electrochemical capacitor C1 capacitance can decline to a great extent.Reduction due to capacitance, electrochemical capacitor C1 just can reduce to the energy that rear class provides and pulsating direct current lower voltage limit Vmin also can step-down, thus it is very poor and be easily accessible under-voltage to cause starting moment product tape loading capability under low temperature, output voltage is finally made to there is situation about repeatedly falling during setting up.Certainly after work a period of time, owing to product itself generates heat, the capacitance of electrochemical capacitor C1 can constantly rise again, simultaneously pulsating direct current lower voltage limit Vmin rising, and product tape loading capability is got back raising.
Clearly this circuit is due to electrochemical capacitor C1 capacitance reduction under low temperature so that it is there is following two defect in start-up course: 1. the energy stored on electrochemical capacitor C1 reduces, the power reduction that DC-DC circuit can export；2. on electrochemical capacitor C1, pulsating dc voltage lower limit Vmin reduces, and product is easily accessible under-voltage, thus output is set up process existence and repeatedly fallen.
Utility model content
In view of this, the technical problems to be solved in the utility model is to provide a kind of circuit improving Switching Power Supply Low temperature start-ability, solves existing current rectifying and wave filtering circuit Low temperature start-ability deficiency and the problem that process is fallen repeatedly is set up in output.
For solving above-mentioned technical problem, this utility model provides a kind of circuit improving Low temperature start-ability, it is applied in AC-DC Switching Power Supply, including: rectification circuit (100), pfc circuit (200), DC-DC circuit (300), electrochemical capacitor C1, commutation diode D1, sequence circuit (600), temperature sensing circuit (400), logic control circuit (500)；
Exchange input output ripple DC voltage after described rectification circuit (100)；
Described temperature sensing circuit (400) sampling ambient temperature output temperature sampled signal export the duty of the described pfc circuit (200) described in logic control circuit (500) control；
When ambient temperature is less than desired temperature, described logic control circuit (500) does not works, described pulsating dc voltage input is to described pfc circuit (200), described pfc circuit (200) starts and starts to described electrochemical capacitor C1 charging, and described pfc circuit (200) produces the duty of the most described DC-DC circuit (300) described in sequence circuit (600) control of ready signal output；
Before described pfc circuit (200) output voltage is not reaching to voltage setting value, described sequence circuit (600) exports under-voltage control signal and described DC-DC circuit (300) cannot be worked；After the output voltage of described pfc circuit (200) reaches voltage setting value, described sequence circuit (600) no longer has under-voltage control signal to export, described DC-DC circuit (300) just can be started working, and obtains electric energy and realize power conversion from described electrochemical capacitor C1；
When described ambient temperature is more than or equal to desired temperature, described logic control circuit (500) output temperature control signal makes described pfc circuit (200) no longer work, now described pulsating dc voltage input, to the most described commutation diode D1, charge to described electrochemical capacitor C1 by described commutation diode D1 and is provided and be given to DC-DC circuit (300) and realize power and change.
The principle Analysis of technique scheme is following (as a example by temperature sampling signal, temperature control signals are as high level；The output voltage setting value of pfc circuit (200) is set to 400V at this；Pfc circuit (200) control chip selects the FAN6982 of Fairchild；DC-DC circuit (300) control chip selects the FAN7601B of Fairchild):
When product starts at low temperatures, described temperature sensing circuit (400) output high level temperature sampling signal is given to described logic control circuit (500), described logic control circuit (500) does not works, and described pfc circuit (200) first starts；The output voltage of the pfc circuit (200) described in initial start stage is less than 400V; the high-impedance state signal that described pfc circuit (200) control chip ready signal output pin (RDY) described in sequence circuit reception exports; thus dragging down described DC-DC circuit (300) control chip latch up protection and soft start control pin (SS) so that described DC-DC circuit (300) can not start；When the output voltage of described pfc circuit (200) reaches 400V; described pfc circuit (200) control chip ready signal output pin (RDY) output presents low configuration; described sequence circuit (600) no longer drags down described DC-DC circuit (300) control chip latch up protection and soft start controls pin (SS) pin level, and described DC-DC circuit (300) starts to start and work with described pfc circuit (200) simultaneously；After described DC-DC circuit (300) work, its control chip raster data model output pin (OUT) voltage pulse output is given to described sequence circuit (600), make described sequence circuit (600) when DC-DC circuit (300) works, described pfc circuit (200) control chip ready signal output pin (RDY) outfan is pulled to input ground, and described DC-DC circuit (300) is no longer by described pfc circuit (200) impact；It is stable 400V DC voltage on now described electrochemical capacitor C1, therefore do not deposit pulsating dc voltage lower limit step-down at low temperatures and the under-voltage problem brought, described electrochemical capacitor C1 is the most no longer the limiting factor of DC-DC circuit (300) output, and now the startup ability of product is the most relevant with the load capacity of described pfc circuit (200).
When after product steady operation a period of time, after described temperature sensing circuit (400) detects high temperature and output low level signal is given to described logic control circuit (500), described logic control circuit (500) output low level drags down described pfc circuit (200) control chip Voltage Feedback input pin (FBPFC) so that described pfc circuit (200) quits work；Described DC-DC circuit (300) works on, and now being charged by commutation diode D1 to electrochemical capacitor C1 and provide is given to described DC-DC circuit (300).
Note:
The RDY pin of FAN6982 is defined as: ready signal output pin, and this pin controls electric sequence, and when FAN6982 conducting and FBPFC pin voltage are more than 2.4V, RDY pin drags down impedance；If FBPFC pin voltage draws high impedance less than 1.15V, RDY pin.
The FBPFC pin of FAN6982 is defined as: Voltage Feedback input pin, the feed back input of PFC voltage loop, the anti-phase input of PFC error amplifier.This pin is connected to PFC by bleeder circuit and exports.
The SS pin of FAN7601B is defined as: latch up protection and soft start control pin.
The OUT pin of FAN7601B is defined as: raster data model output pin.
Improvement as foregoing circuit, the described circuit improving Low temperature start-ability also includes a current detection circuit (700), described DC-DC circuit (300) the output size of current described in current detection circuit (700) detection, output feedback signal is to described logic control circuit (500), and described logic control circuit (500) further determines whether to close described pfc circuit (200) according to size of current on the basis of temperature detection.
Above-mentioned improvement project be not at high temperature directly close described in pfc circuit (200), thus the product apparent energy that improves in the range of total temperature under underloading of the function making full use of pfc circuit (200) rather than single solution cold-starting problem.
It is characterised by as described rectification circuit (100): comprise an input and an outfan；The outfan of described rectification circuit (100) is divided into output to rectify and outfan is born；Described exchange input flows into from described input, and described pulsating dc voltage flows out from described outfan.
It is characterised by as described pfc circuit (200): comprise an input, one outfan, two functional pins of pfc circuit (200) control chip: ready signal output pin (RDY), Voltage Feedback input pin (FBPFC)；Described input and outfan are all divided into positive and negative；The outfan of the rectification circuit (100) described in input connection of described pfc circuit (200)；The outfan of described pfc circuit (200) is connected with the input of described DC-DC circuit (300)；Described electrochemical capacitor C1 be connected in parallel on the output of described pfc circuit (200) outfan rectify and outfan negative between；The anode of described diode D1 connects the input of described pfc circuit (200) and rectifies, and the negative electrode of described diode D1 connects the output of described pfc circuit (200) and rectifies.
It is characterised by as described DC-DC circuit (300): comprise an input; one outfan, two functional pins of DC-DC circuit (300) control chip: latch up protection and soft start control pin (SS), raster data model pin (OUT)；The outfan of the pfc circuit (200) described in input termination of described DC-DC circuit (300), the outfan output voltage (Vout) of described DC-DC circuit (300).
As a kind of detailed description of the invention of described sequence circuit (600), including: resistance R601, resistance R602, resistance R603, electric capacity C601, diode D601, field effect transistor TR601, field effect transistor TR602；The ready signal of described pfc circuit (200) is followed by input ground through the grid of described field effect transistor TR601, source electrode successively；Described resistance R601 one end is connected with the grid of described field effect transistor TR601, and another terminates the first auxiliary electric power supply voltage (VCC1)；The outfan that drain electrode is described sequence circuit (600) of described field effect transistor TR601, controls pin (SS) with described DC-DC circuit (300) control chip latch up protection and soft start and is connected；Described DC-DC circuit (300) control chip raster data model output pin (OUT) is followed by input ground through the anode of described diode D601, the negative electrode of described diode D601, described resistance R602, the grid of described field effect transistor TR602, the source electrode of described field effect transistor TR602 successively；The drain electrode of described field effect transistor TR602 is connected to the grid of described field effect transistor TR601；Described resistance R603 is connected in parallel between the negative electrode of described diode D601 and input ground；Described electric capacity C601 is in parallel with described resistance R603.
As a kind of specific embodiment of temperature sensing circuit (400), including: resistance R401, resistance R402, critesistor R403, resistance R404, error amplifier U401 and electric capacity C401；Second auxiliary electric power supply voltage (VCC2) is followed by output ground through described resistance R401, the negative electrode of described error amplifier U401, the anode of described error amplifier U401 successively；The benchmark foot of described error amplifier U401 is connected with negative electrode, and the negative electrode of described error amplifier U401 is followed by output ground through described resistance R402, described critesistor R403 successively；Described electric capacity C601 is in parallel with described critesistor R403；Described resistance R404 mono-terminates described resistance R402 and the junction point of described critesistor R403, the temperature sampling signal described in other end output.
As a kind of specific embodiment of logic control circuit (500), including: single-chip microcomputer U501, resistance R501, resistance R502, resistance R503, resistance R504, resistance R505, optocoupler OC501, field effect transistor TR501 and field effect transistor TR502；The temperature sampling signal described in first I/O mouth (PA0) reception of described single-chip microcomputer U501；Second I/O mouth (PA1) of described single-chip microcomputer is followed by output ground through described resistance R501, the grid of described field effect transistor TR501, the source electrode of described field effect transistor TR501 successively；Described resistance R502 is parallel between grid and the source electrode of described field effect transistor TR501；The drain electrode of described field effect transistor TR501 is followed by the second auxiliary electric power supply voltage (VCC2) through the negative electrode of light emitting diode of described optocoupler OC501, the anode of the light emitting diode of described optocoupler OC501, described resistance R503 successively；The colelctor electrode of described optocoupler OC501 audion is connected to the first auxiliary electric power supply voltage (VCC1) after described resistance R504；The emitter stage of described optocoupler OC501 audion is followed by input ground through the grid of described field effect transistor TR502, source electrode successively；Described resistance R505 is connected in parallel between grid and the source electrode of described field effect transistor TR502；The temperature control signals described in drain electrode output of described field effect transistor TR502, is connected with described pfc circuit (200) control chip Voltage Feedback input pin (FBPFC).
As a kind of specific embodiment of described current detection circuit (700), including resistance R701, resistance R702, resistance R703, resistance R704, resistance R705, error amplifier U701；Described resistance R701 is serially connected in described DC-DC circuit (300) outfan and bears, the negative junction point of described resistance R701 and described DC-DC circuit (300) outfan successively through described resistance R702, described error amplifier U701 input negative terminal, described resistance R703, the outfan of described error amplifier U701, described resistance R704 to described logic control circuit (500)；The input decent resistance R705 of described error amplifier U701 is to output ground, and described electric capacity C701 is connected in parallel on described resistance R703 two ends.
The beneficial effects of the utility model are as follows:
1, the characteristic that under this utility model utilizes low temperature, the peakflux density of magnetic core is significantly increased, improves the overpower point of pfc circuit under low temperature, effectively raises the Low temperature start-ability of product；
2, the overpower at normal temperatures of the pfc circuit in this utility model point is less, and PFC inductance, metal-oxide-semiconductor constant power device can use less specification, reduce overall volume；
3, often, PFC works under light load mode under high temperature, does not works, effectively reduce the lower apparent energy of light load of product, reduce client stand-by power consumption during heavy duty.
Accompanying drawing explanation
Fig. 1 is the block diagram of conventional switching power supply input rectification circuit；
Fig. 2 is voltage waveform on electrochemical capacitor C1 in conventional rectification circuit；
Fig. 3 is circuit function block diagram one of the present utility model；
Fig. 4 is the circuit diagram that this utility model implements；
Fig. 5 is circuit function block diagram two of the present utility model；
Fig. 6 is the circuit diagram that this utility model implements three.
Detailed description of the invention
The design of technical solutions of the utility model is: judge ambient temperature by temperature sensing circuit, using detected value as the input signal of logic control circuit, logic control circuit exports logic level according to temperature conditions, and this logic level can determine whether pfc circuit works.When product is under high temperature, logic control circuit turns off pfc circuit, and circuit is charged to rear class electrochemical capacitor by diode, and product can normally work；When product is under low temperature, logic control circuit opens pfc circuit, pfc circuit boost and charge to electrochemical capacitor, now can obtain higher DC voltage on electrochemical capacitor, be substantially improved the poor starting problem caused due to electrochemical capacitor low-temperature characteristics.Simultaneously because pfc circuit has only to work at low temperatures in this circuit, therefore its magnetic elements and power device etc. can select much smaller than conventional specification.
Further, a current detection circuit can be increased on the basis of above-mentioned design, detection output current signal feeds back to logic control element, thus judge whether to close pfc circuit according to size of current on the basis of temperature detection, rather than the most directly close pfc circuit, so can make full use of the function of pfc circuit, the product apparent energy under underloading rather than single solution cold-starting problem in the range of raising total temperature.
It is below functional block diagram of the present utility model:
Seeing Fig. 3 is functional block diagram one of the present utility model, including exchange input, rectification circuit 100, pfc circuit 200, DC-DC circuit 300, temperature sensing circuit 400, logic control circuit 500, sequence circuit 600, electrochemical capacitor C1, diode D1；
Exchange input, rectification circuit 100, pfc circuit 200, electrochemical capacitor C1, DC-DC circuit 300 are sequentially connected in series rear output voltage Vout；
The anode of diode D1 connect the input of pfc circuit 200 just, negative electrode just connecing the output of pfc circuit 200；
Pfc circuit 200 control chip comprises two functional pins: ready signal output pin RDY, Voltage Feedback input pin FBPFC；
DC-DC circuit 300 control chip comprises two functional pins: latch up protection and soft start control pin SS, raster data model output pin OUT；
The first input end of the output termination logic control circuit 500 of temperature sensing circuit 400；The output termination pfc circuit 200 control chip feed back input pin FBPFC of logic control circuit 500；The first input end of sequence circuit 600 connects pfc circuit 200 control chip ready signal output pin RDY, the second input termination DC-DC circuit 300 control chip raster data model output pin OUT, output termination DC-DC circuit 300 control chip latch up protection and soft start and controls pin SS.
Fig. 5 is functional block diagram two of the present utility model, adds a current detection circuit 700, and the outfan of input termination DC-DC circuit 300 of current detection circuit 700, output connect the second input of logic control circuit 500.
Further illustrate below in conjunction with implementing circuit.
Embodiment one
Fig. 4 is this utility model first embodiment circuit theory diagrams, it then follows the annexation of above-mentioned functions block diagram one, and exchange input rectifying is become pulsating dc voltage to be supplied to the input of pfc circuit 200 by rectification circuit 100；Pfc circuit 200 is stored in electrochemical capacitor C1 after being boosted by pulsating dc voltage；Electrochemical capacitor C1 is connected on the input of DC-DC circuit 300, provides energy to it；Diode D1 provides charge path by rectification circuit to electrochemical capacitor C1 when pfc circuit does not works；
Temperature sensing circuit 400 includes: resistance R401, resistance R402, critesistor R403, resistance R404, error amplifier U401 and electric capacity C401；Second auxiliary electric power supply voltage VCC2 is followed by output ground through resistance R401, the negative electrode of error amplifier U401, the anode of error amplifier U401 successively；The benchmark foot of error amplifier U401 is connected with negative electrode, and the negative electrode of error amplifier U401 is followed by output ground through resistance R402, critesistor R403 successively；Electric capacity C601 is in parallel with critesistor R403；Resistance R404 mono-terminating resistor R402 and the junction point of critesistor R403, the output signal of the temperature sensing circuit 400 that the other end is, connect the I/O mouth PA1 foot of single-chip microcomputer in logic control circuit 500；
Logic control circuit 500 includes: single-chip microcomputer U501, resistance R501, resistance R502, resistance R503, resistance R504, resistance R505, optocoupler OC501, field effect transistor TR501 and field effect transistor TR502；Second I/O mouth PA1 of single-chip microcomputer U501 receives the output signal of temperature sensing circuit 400；First I/O mouth PA0 of single-chip microcomputer U501 is followed by output ground through resistance R501, the grid of field effect transistor TR501, the source electrode of field effect transistor TR501 successively；Resistance R502 is parallel between the grid of field effect transistor TR501 and source electrode；The drain electrode of field effect transistor TR501 is followed by the second auxiliary electric power supply voltage VCC2 through the negative electrode of light emitting diode of optocoupler OC501, the anode of light emitting diode of optocoupler OC501, resistance R503 successively；The colelctor electrode of optocoupler OC501 audion is connected to the first auxiliary electric power supply voltage VCC1 after resistance R504；The emitter stage of optocoupler OC501 audion is followed by input ground through the grid of field effect transistor TR502, the source electrode of field effect transistor TR502 successively；Resistance R505 is connected in parallel between the grid of field effect transistor TR502 and source electrode；The drain electrode of field effect transistor TR502 is the single-chip microcomputer control signal outfan to pfc circuit 200, is connected with pfc circuit 200 control chip Voltage Feedback input pin FBPFC；
Sequence circuit 600 includes: resistance R601, resistance R602, resistance R603, electric capacity C601, diode D601, field effect transistor TR601, field effect transistor TR602；The ready signal of pfc circuit 200 ground connection after the grid of field effect transistor TR601, source electrode connect successively；Resistance R601 one end is connected with the grid of field effect transistor TR601, and another terminates the first auxiliary electric power supply voltage VCC1；The outfan that drain electrode is sequence circuit 600 of field effect transistor TR601, this point controls pin SS with DC-DC circuit 300 control chip latch up protection and soft start and is connected；DC-DC circuit 300 control chip raster data model output pin OUT successively through the anode of diode D601, the negative electrode of diode D601, resistance R602, the grid of field effect transistor TR602, field effect transistor TR602 source electrode to input ground；The drain electrode of field effect transistor TR602 is connected to the grid of field effect transistor TR601；Resistance R603 is connected in parallel between the negative electrode of diode D601 and input ground；Electric capacity C601 is in parallel with resistance R603.
The present embodiment operation principle is as follows:
nullAfter exchange powers on，Rectification circuit 100、Pfc circuit 200、Commutation diode D1、Electrochemical capacitor C1 first works，DC-DC circuit 300 is locked，After pfc circuit 200 output is set up，Just start DC-DC circuit 300，The sequential realizing pfc circuit 200 and DC-DC circuit 300 starts，Sequential starting pinciple is as follows: before pfc circuit 200 output voltage reaches voltage setting value (this voltage is generally 400V)，Pfc circuit 200 control chip ready signal output pin RDY provides high impedance signal，After sequence circuit 600 receives described high impedance signal，Field effect transistor TR601 turns on，Thus drag down latch up protection and the soft start control pin SS of DC-DC circuit 300，Make DC-DC circuit 300 locked；After the output level of pfc circuit 200 reaches voltage setting value, pfc circuit 200 control chip ready signal output pin RDY provides Low ESR signal, and field effect transistor TR601 is ended, thus DC-DC circuit 300 can normally start；After DC-DC circuit 300 is started working, DC-DC circuit 300 control chip raster data model output pin OUT exports drive pulse signal, it is stored in electric capacity C601 by diode D601, with maintain field effect transistor TR602 constant conduction state so that field effect transistor TR601 remain off state guarantee pfc circuit 200 control chip ready signal output pin RDY no longer affect startup after DC-DC circuit 300；Follow-up pfc circuit 200 closes has no progeny, and is not result in that DC-DC circuit 300 is closed.
Error amplifier U401 in temperature sensing circuit 400 and resistance R401 is to mono-constant supply voltage of sampling resistor R402 and R403, critesistor R403 resistance at different temperatures is different, thus pressure drop is different on critesistor R403, the level being given to logic control circuit 500 is also different (single-chip microcomputer can freely define a height of low temperature of level or level is low for low temperature)；Electric capacity C401 and resistance R404 is RC filter circuit, for anti-tampering；
In logic control circuit 500, the I/O mouth PA1 of single-chip microcomputer U501 receives temperature sampling signal, thus performs corresponding program and determine whether to turn off pfc circuit 200:
When temperature sensing circuit 400 detects low-temperature signal; I/O mouth PA1 in logic control circuit 500 and PA2 output low level; logic control circuit 500 does not controls pin SS to pfc circuit 200 control chip Voltage Feedback input pin FBPFC and DC-DC circuit 300 control chip latch up protection and soft start and performs any operation; now due to the existence of sequence circuit 600; achieve pfc circuit 200 and first set up output, the sequential that then DC-DC circuit 300 just starts.In start-up course, the voltage on described electrochemical capacitor C1 will not have a pulsating dc voltage in shown in Fig. 2, but stable 400V, thus the load capacity of product low temperature is the strongest.
After temperature sensing circuit 400 detects that temperature raises, single-chip microcomputer U501 in logic control circuit 500 exports high level by PA1 pin, field effect transistor TR501 is turned on, the LEDs ON of optocoupler OC501, the triode ON of optocoupler OC501 is so that field effect transistor TR502 turns on, pfc circuit 200 control chip Voltage Feedback input pin FBPFC is pulled to ground, thus turn off pfc circuit 200, circuit is charged to rear class electrochemical capacitor C1 by diode D1, and product still can normally work.
Due to electrochemical capacitor C1 after a period of operation, along with the rising of temperature, the capacitance of electric capacity is quickly gone up, and its characteristic is little with room temperature difference, now turn off pfc circuit 200 and already handle the problem that low temperature load capacity is the strongest well, can guarantee that again pfc circuit 200 will not damage because of overpower.
Embodiment two
Embodiment two is completely the same with embodiment one schematic diagram, and difference is that single-chip microcomputer U501 control mode is different, and in embodiment one, single-chip microcomputer U501, by monitoring temperature, closes pfc circuit 200 after temperature raises.This embodiment then can be controlled by the timer within single-chip microcomputer U501, by program setting, after single-chip microcomputer U501 powers on a period of time, can be closed by pfc circuit 200, only need to guarantee that the capacitance of electrochemical capacitor C1 rises to a certain degree.
The present embodiment carries out timing by single-chip microcomputer U501, turns off the control mode of pfc circuit 200 work after work a period of time, and control mode is simpler, the most there is not the problems such as temperature sampling error is bigger.
Embodiment three
Fig. 6 is the schematic diagram of this utility model the 3rd embodiment, embodiment three is to have increased a current detection circuit 700 newly with the difference of embodiment two, current detection circuit 700 include resistance R701, resistance R702, resistance R703, resistance R704, resistance R705, error amplifier U701；Resistance R701 is serially connected between the load of DC-DC circuit 300 outfan, the negative junction point of resistance R701 and DC-DC circuit outfan, the threeth I/O mouth PA2 of resistance R703, the outfan of error amplifier U701, resistance R704 to single-chip microcomputer negative through the input of resistance R702, error amplifier U701 successively；The input decent resistance R705 of error amplifier U701 is to output ground, and electric capacity C701 is connected in parallel on resistance R703 two ends.
Current detection circuit 700 can detect output current signal and feed back to logic control circuit 500, thus judge whether to close pfc circuit 200 according to size of current on the basis of temperature detection, rather than the most directly close pfc circuit 200, so can improve the product apparent energy under underloading in the range of total temperature, make full use of the function of pfc circuit 200 rather than single solution cold-starting problem.
Certainly, above-described embodiment also has temperature detection and time control two ways to close pfc circuit 200, and this is the equivalent technical solutions of the application claim for a person skilled in the art, in order to save length, do not repeat in embodiment and claims.
In addition; this utility model is those skilled in the art's understanding for convenience when analyzing operation principle and describing annexation; employ FAN6982 and the FAN7601B chip of Fairchild and relevant functional pin etc. thereof; this is not to be construed as the restriction to the application protection domain; those skilled in the art can make other equivalent, and these equivalents fall within protection domain of the present utility model.
Embodiment of the present utility model is not limited to this; according to foregoing of the present utility model; utilize ordinary technical knowledge and the customary means of this area; without departing under this utility model above-mentioned basic fundamental thought premise; this utility model can also be made the amendment of other various ways, replace or change, as replaced with by audion Q1 within the scope of metal-oxide-semiconductor etc. all falls within this utility model rights protection.
Claims (9)
1. improve a circuit for Low temperature start-ability, be applied in AC-DC Switching Power Supply, including: rectification circuit (100),
Pfc circuit (200), DC-DC circuit (300), electrochemical capacitor C1, commutation diode D1, sequence circuit (600), temperature are examined
Slowdown monitoring circuit (400), logic control circuit (500)；
Exchange input output ripple DC voltage after described rectification circuit (100)；
Described temperature sensing circuit (400) sampling ambient temperature output temperature sampled signal export described logic control electricity
The duty of the pfc circuit (200) described in the control of road (500)；
When ambient temperature is less than desired temperature, described logic control circuit (500) does not works, described pulsating dc voltage
Input is to described pfc circuit (200), and described pfc circuit (200) starts and start to described electrochemical capacitor C1 charging,
Described pfc circuit (200) produces ready signal output to the DC-DC circuit (300) described in described sequence circuit (600) control
Duty；
Before described pfc circuit (200) output voltage is not reaching to voltage setting value, described sequence circuit (600) exports under-voltage
Control signal makes described DC-DC circuit (300) to work, when the output voltage of described pfc circuit (200) reaches electricity
After pressure setting value；Described sequence circuit (600) no longer has under-voltage control signal to export, described DC-DC circuit (300) ability
Start working, from described electrochemical capacitor C1, obtain electric energy realize power conversion；
When described ambient temperature is more than or equal to desired temperature, described logic control circuit (500) output temperature controls letter
Number described pfc circuit (200) no longer being worked, now described pulsating dc voltage input is to the most described commutation diode
D1, is charged and provides to described electrochemical capacitor C1 by described commutation diode D1 and be given to described DC-DC circuit (300)
Realize power conversion.
The circuit of raising Low temperature start-ability the most according to claim 1, it is characterised in that: also include a current detecting electricity
Road (700), described DC-DC circuit (300) the output size of current described in current detection circuit (700) detection, output feedback
Signal to described logic control circuit (500), described logic control circuit (500) on the basis of temperature detection according to electric current
Size further determines whether to close described pfc circuit (200).
The circuit of raising Low temperature start-ability the most according to claim 1, it is characterised in that: described rectification circuit (100)
Comprise an input and an outfan；The outfan of described rectification circuit (100) is divided into output to rectify and outfan is born；Described
Exchange input flow into from described input, described pulsating dc voltage flows out from described outfan.
The circuit of raising Low temperature start-ability the most according to claim 1, it is characterised in that: described pfc circuit (200)
Comprise two functional pins of an input, an outfan, and pfc circuit (200) control chip: ready signal exports
Pin (RDY), Voltage Feedback input pin (FBPFC)；Described input and outfan are all divided into positive and negative；Described PFC
The outfan of the rectification circuit (100) described in input connection of circuit (200)；The outfan of described pfc circuit (200) and institute
The input of the DC-DC circuit (300) stated is connected；Described electrochemical capacitor C1 is connected in parallel on described pfc circuit (200) output
The output of end rectify and outfan negative between；The anode of described diode D1 connects the input of described pfc circuit (200) and rectifies,
The negative electrode of described diode D1 connects the output of described pfc circuit (200) and rectifies.
The circuit of raising Low temperature start-ability the most according to claim 1, it is characterised in that: described DC-DC circuit (300)
Comprise two functional pins of an input, an outfan, and DC-DC circuit (300) control chip: latch up protection
Pin (SS), raster data model pin (OUT) is controlled with soft start；The PFC described in input termination of described DC-DC circuit (300)
The outfan of circuit (200), the outfan output voltage (Vout) of described DC-DC circuit (300).
The circuit of raising Low temperature start-ability the most according to claim 1, it is characterised in that: described sequence circuit (600)
Including: resistance R601, resistance R602, resistance R603, electric capacity C601, diode D601, field effect transistor TR601, field
Effect pipe TR602；The ready signal of described pfc circuit (200) is successively through grid, the source electrode of described field effect transistor TR601
It is followed by input ground；Described resistance R601 one end is connected with the grid of described field effect transistor TR601, another termination first auxiliary
Power supply voltage (VCC1)；The outfan that drain electrode is described sequence circuit (600) of described field effect transistor TR601, with
Described DC-DC circuit (300) control chip latch up protection controls pin (SS) with soft start and is connected；Described DC-DC circuit
(300) control chip raster data model output pin (OUT) is successively through anode, the described diode of described diode D601
The negative electrode of D601, described resistance R602, the grid of described field effect transistor TR602, described field effect transistor TR602
Source electrode is followed by input ground；The drain electrode of described field effect transistor TR602 is connected to the grid of described field effect transistor TR601；Described
Resistance R603 be connected in parallel on described diode D601 negative electrode and input ground between；Described electric capacity C601 and described electricity
Resistance R603 is in parallel.
The circuit of raising Low temperature start-ability the most according to claim 1, it is characterised in that: described temperature sensing circuit
(400) including: resistance R401, resistance R402, critesistor R403, resistance R404, error amplifier U401 and electric capacity
C401；Second auxiliary electric power supply voltage (VCC2) is successively through described resistance R401, the moon of described error amplifier U401
Pole, the anode of described error amplifier U401 are followed by output ground；The benchmark foot of described error amplifier U401 and negative electrode phase
Even, the negative electrode of described error amplifier U401 is followed by defeated through described resistance R402, described critesistor R403 successively
Go out ground；Described electric capacity C601 is in parallel with described critesistor R403；Described resistance R404 mono-terminates described resistance
R402 and the junction point of described critesistor R403, the temperature sampling signal described in other end output.
The circuit of raising Low temperature start-ability the most according to claim 1, it is characterised in that: described logic control circuit
(500) including: single-chip microcomputer U501, resistance R501, resistance R502, resistance R503, resistance R504, resistance R505, light
Coupling OC501, field effect transistor TR501 and field effect transistor TR502；First I/O mouth (PA0) of described single-chip microcomputer U501
Temperature sampling signal described in reception；Second I/O mouth (PA1) of described single-chip microcomputer is successively through described resistance R501, described
The grid of field effect transistor TR501, the source electrode of described field effect transistor TR501 be followed by output ground；Described resistance R502 is also
It is coupled between grid and the source electrode of described field effect transistor TR501；The drain electrode of described field effect transistor TR501 is successively through described
The negative electrode of the light emitting diode of optocoupler OC501, the anode of light emitting diode of described optocoupler OC501, described resistance R503
It is followed by the second auxiliary electric power supply voltage (VCC2)；The colelctor electrode of described optocoupler OC501 audion is through described resistance R504
After be connected to the first auxiliary electric power supply voltage (VCC1)；The emitter stage of described optocoupler OC501 audion is successively through described field
The grid of effect pipe TR502, source electrode are followed by input ground；Described resistance R505 is connected in parallel on described field effect transistor TR502
Between grid and source electrode；The temperature control signals described in drain electrode output of described field effect transistor TR502, with described PFC electricity
Road (200) control chip Voltage Feedback input pin (FBPFC) is connected.
The circuit of raising Low temperature start-ability the most according to claim 2, it is characterised in that: described current detection circuit
(700) resistance R701, resistance R702, resistance R703, resistance R704, resistance R705, error amplifier U701 are included；
Described resistance R701 is serially connected in described DC-DC circuit (300) outfan and bears, described resistance R701 and described DC-DC
The negative junction point of circuit (300) outfan successively through described resistance R702, the input negative terminal of described error amplifier U701,
Described resistance R703, the outfan of described error amplifier U701, described resistance R704 are to described logic control
Circuit (500)；The input decent resistance R705 of described error amplifier U701 is to output ground, and described electric capacity C701 is also
It is associated in described resistance R703 two ends.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620294862.4U CN205596013U (en) | 2016-04-11 | 2016-04-11 | Improve circuit of cold -starting ability |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620294862.4U CN205596013U (en) | 2016-04-11 | 2016-04-11 | Improve circuit of cold -starting ability |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN205596013U true CN205596013U (en) | 2016-09-21 |
Family
ID=56921851
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201620294862.4U Withdrawn - After Issue CN205596013U (en) | 2016-04-11 | 2016-04-11 | Improve circuit of cold -starting ability |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN205596013U (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105763035A (en) * | 2016-04-11 | 2016-07-13 | 广州金升阳科技有限公司 | Method and circuit for improving low-temperature starting capacity |
| CN109669061A (en) * | 2019-01-31 | 2019-04-23 | 广州金升阳科技有限公司 | A kind of current sample compensation circuit |
| CN111023441A (en) * | 2019-12-30 | 2020-04-17 | Tcl空调器(中山)有限公司 | Air conditioner control method and system, storage medium and air conditioner |
| CN113448360A (en) * | 2020-03-26 | 2021-09-28 | 中磊电子（苏州）有限公司 | Network device with temp. control switch, heater, latch and power supply circuit |
-
2016
- 2016-04-11 CN CN201620294862.4U patent/CN205596013U/en not_active Withdrawn - After Issue
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105763035A (en) * | 2016-04-11 | 2016-07-13 | 广州金升阳科技有限公司 | Method and circuit for improving low-temperature starting capacity |
| CN105763035B (en) * | 2016-04-11 | 2018-06-29 | 广州金升阳科技有限公司 | A kind of method and circuit for improving Low temperature start-ability |
| CN109669061A (en) * | 2019-01-31 | 2019-04-23 | 广州金升阳科技有限公司 | A kind of current sample compensation circuit |
| CN111023441A (en) * | 2019-12-30 | 2020-04-17 | Tcl空调器(中山)有限公司 | Air conditioner control method and system, storage medium and air conditioner |
| CN111023441B (en) * | 2019-12-30 | 2021-08-24 | Tcl空调器(中山)有限公司 | Air conditioner control method and system, storage medium and air conditioner |
| CN113448360A (en) * | 2020-03-26 | 2021-09-28 | 中磊电子（苏州）有限公司 | Network device with temp. control switch, heater, latch and power supply circuit |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| AV01 | Patent right actively abandoned | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20160921 Effective date of abandoning: 20180629 |