CN200994060Y - PFC overcurrent protection circuit and air conditioner with same - Google Patents
PFC overcurrent protection circuit and air conditioner with same Download PDFInfo
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- CN200994060Y CN200994060Y CNU2006201618407U CN200620161840U CN200994060Y CN 200994060 Y CN200994060 Y CN 200994060Y CN U2006201618407 U CNU2006201618407 U CN U2006201618407U CN 200620161840 U CN200620161840 U CN 200620161840U CN 200994060 Y CN200994060 Y CN 200994060Y
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/30—Reactive power compensation
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Abstract
The utility model discloses a PFC overcurrent protective circuit and an air conditioner having the protective circuit. The PFC overcurrent protective circuit comprises a signal input terminal, a signal output terminal, a computation comparator and a sampling resistor. Current signals are converted into voltage signals when the system current for the air conditioner passes the sampling resistor, and the voltage signals are inputted from the signal input terminal, further added with a bias voltage, and at last connected with the cophase input terminal of the computation comparator. The inverse input terminal of the computation comparator is connected with a reference voltage, and the output terminal of the computation comparator is connected with the control circuit of the air conditioner via the signal output terminal. The control circuit controls the working status of the PFC circuit in the air conditioner according to the voltage signals received. The utility model adds weak sampling signals to the reference voltage by arranging a bias voltage to set the working point of the computation comparator at a relatively high voltage value, thus improving the precision of the signal sampling and helping increase the reliability of the PFC overcurrent protective circuit.
Description
Technical field
The utility model belongs to the current foldback circuit technical field, specifically, relates to the current foldback circuit technology of a kind of APFC PFC.
Background technology
The current foldback circuit of existing APFC (Power Factor Correction:PFC) adopts Direct Sampling method relatively more; the direct input comparator of faint useful signal; for example; when sampling resistor is 0.02 ohm; when input current is 20A; the magnitude of voltage that sampling obtains only is 0.4V, and signal amplitude is very little.Simultaneously, for suitable working point is set, reference voltage also must be the low-voltage small-signal.Will bring following problem like this: the one, because the existence of comparator input capacitance makes the protective circuit reaction time long, do not reach the purpose of quick protection; The 2nd, because the dispersiveness of device makes circuit not protect precision low thereby cause by the working point work of setting, even the mistake protection.And, then require comparator must have very little input capacitance and higher consistency for components and parts, and uniformity in product performance when producing in batches with assurance, inevitable requirement adopts more high performance components and parts like this, thereby system cost is increased.
Summary of the invention
Detected signal is the low problem of current foldback circuit protection precision of small-signal to the utility model in the prior art in order to solve; a kind of PFC current foldback circuit is provided; by bias voltage is set, faint detected signal is superimposed on the bias voltage, thereby has improved accuracy of detection.
For solving the problems of the technologies described above, the utility model is achieved by the following technical solutions:
A kind of PFC current foldback circuit and the air conditioner with described protective circuit comprise signal input part, signal output part, computing comparator and sampling resistor; After the system power of air conditioner changes current signal into voltage signal by sampling resistor, by the input of described signal input part, and then with bias voltage stack after be connected to the in-phase input end of described computing comparator; The inverting input of described computing comparator connects reference voltage, and output is by the control circuit of described signal output part connection air conditioner, and described control circuit is according to the operating state of pfc circuit in the voltage signal control of Electric potentials air-conditioning system that receives.
In order to make protective circuit have stagnant chain rate, between the in-phase input end of described computing comparator and output, be connected with a feedback resistance than function.
In the utility model, described bias voltage and reference voltage generate by the conversion of one+15V DC power supply; Wherein, described+15V DC power supply connects a voltage stabilizing didoe by filter circuit, generates stable voltage signal, generates described reference voltage by resistance pressure-dividing network, the inverting input of concatenation operation comparator on the one hand; Export described bias voltage by a resistance on the other hand, with the in-phase input end that is input to the computing comparator after the described sampled voltage signal stack.The output of described computing comparator is through pull-up resistor connection+3.3V DC power supply.
Described sampled voltage signal is a negative voltage signal, connects the in-phase input end of described computing comparator by the capacitance-resistance filter network, with the noise jamming in the filtering circuit.
Compared with prior art; advantage of the present utility model and good effect are: current foldback circuit of the present utility model is by being provided with bias voltage; faint efficiently sampling signal is superimposed on this reference voltage; thereby the working point that makes comparator is arranged on the higher voltage value; so not only can improve the accuracy of small-signal sampling; and the higher voltage value can be full of electricity at short notice with the input capacitance of comparator, thereby effectively avoided the influence of input capacitance to protective circuit reaction time and protection precision.PFC current foldback circuit of the present utility model forms the chain rate that stagnates than circuit form by being connected feedback resistance between the in-phase input end of comparator and the output, on the one hand the effectively various instantaneous interference in the filtering appts; Make that on the other hand the current threshold that enters guard mode is higher than the threshold value that withdraws from protection, thereby leave bigger protection allowance, effectively improved the reliability of system.
Description of drawings
Fig. 1 is a PFC current foldback circuit schematic diagram of the present utility model;
Fig. 2 is a system block diagram of using PFC current foldback circuit shown in Figure 1 in air conditioner.
Embodiment
Below in conjunction with the drawings and specific embodiments the utility model is described in further detail.
The utility model is in order to solve the small-signal current foldback circuit reflection overlong time that exists in the prior art; device disperses to be provided with to cause protects precision low; even the problem of misoperation; a kind of PFC current foldback circuit is provided; by the higher bias voltage of amplitude is set; faint detected signal is superimposed on the bias voltage; the working point of comparator is adjusted on the higher voltage value; like this can be in advance the input capacitance of comparator be full of electricity, thereby avoids input capacitance that the reaction time and the protection precision of current foldback circuit are impacted.
Embodiment one, and Fig. 1 shows the schematic diagram of described PFC current foldback circuit, comprise signal input part Vin, signal output part Vout, computing comparator U1 ,+15V dc supply input and sampling resistor R1.+ 15V direct voltage after capacitor C E1, the C1 Filtering Processing, is exported stable 5.1V reference voltage through resistance R 3 current limlitings under the effect of voltage stabilizing didoe ZD1.This reference voltage is leaded up to resistance R 6 and is added to the in-phase input end of comparator U1, another road is passed through to export 2.55V voltage after resistance R 4, the R5 dividing potential drop, be applied to the inverting input of comparator U1, as the work reference voltage of whole comparison circuit, i.e. U-=2.55V.System power I is input in the filtration protective circuit by signal input part Vin after sampling resistor R1 is transformed into voltage signal Vi.As seen from Figure 1, described sampled voltage signal Vi is a negative voltage signal, and system power I is big more, and the numerical value of sampled voltage signal Vi is more little.After described sampled voltage signal Vi handles through the low pass filter of being made up of resistance R 2 and capacitor C 3, with the 5.1V reference voltage superpose obtain comparator U1 in-phase input end voltage U+.Along with the increase of system power I, sampled voltage signal Vi will reduce gradually, and U+ also will reduce gradually simultaneously.When system power I hour, U+＞2.55V, comparator U1 is output as+3.3V; As system power I during greater than a certain numerical value, U+＜2.55V, comparator U1 is output as 0V.U1 is output as 0V when comparator, and when promptly system power I was greater than a certain numerical value, system entered the overcurrent protection state.
In addition, this circuit is introduced positive feedback by resistance R 7, makes circuit have stagnant chain rate than function, and when system power I reached a certain numerical value, circuit can enter guard mode according to the protection point that sets like this.But; stagnate chain rate than the operation principle of circuit as can be known according to homophase input: the system power value that circuit withdraws from guard mode is less than the system power that enters guard mode; even like this just in case the non-stop-machine situation in protection back occurs; also only be reduced to below a certain security value (s) at electric current; the de-preservation state is just understood by system, thereby has improved the reliability of system.
Among Fig. 2, R1 is a sample resistance, and 1 is current rectifying and wave filtering circuit; 2 is pfc circuit; 3 is other functional circuits of system; 4 is the control circuit of Driven Compressor work; 5 is PFC current foldback circuit shown in Figure 1.
When the air conditioner running, the air-conditioning system electric current is input in the stagnant ring-like PFC current foldback circuit 5 as shown in Figure 1 after sample resistance R1 changes current signal into voltage signal Vi.Because system power flows to relation, described sampled voltage signal Vi is a negative voltage signal, and reduces with the increase of system power.In order to improve the accuracy of small-signal sampling, in current foldback circuit 5, the bias voltage that sampled voltage signal Vi and a potential value is higher is superimposed, as a comparison the in-phase input end voltage U of device+.Along with the increase of air-conditioning system electric current, sampled voltage signal Vi will reduce gradually, and U+ also will reduce gradually simultaneously.When system power during less than the mistakes flow valuve set, comparator is exported positive voltage value; When system power during greater than the mistakes flow valuve set, comparator is exported zero level.The control circuit 4 of Driven Compressor work is controlled the operating state of pfc circuit 2 by the current potential of judging described comparator output signal.When system power when crossing flow valuve, system enters the overcurrent protection state, pfc circuit 2 stops to boost, thereby has reached the purpose of protection pfc circuit 2.
The utility model is superimposed on faint detected signal on the bias voltage, thereby has improved accuracy of detection by bias voltage is set.In addition; by being connected feedback resistance between the in-phase input end of comparator and the output; make protective circuit have stagnant chain rate than function; thereby effectively filtering various instantaneous interference; make that simultaneously the current threshold that enters guard mode is higher than the threshold value that withdraws from protection; thereby leave bigger protection allowance, improved the protection precision.
Certainly; above-mentioned explanation is not to be to restriction of the present utility model; the utility model also is not limited in above-mentioned giving an example, and variation, remodeling, interpolation or replacement that those skilled in the art are made in essential scope of the present utility model also should belong to protection range of the present utility model.
Claims (10)
1. PFC current foldback circuit, comprise signal input part (Vin), signal output part (Vout), computing comparator (U1) and sampling resistor (R1), it is characterized in that: after system power changes current signal into voltage signal by sampling resistor (R1), by described signal input part (Vin) input, so with bias voltage stack after be connected to the in-phase input end of described computing comparator (U1); The inverting input of described computing comparator (U1) connects reference voltage, and output connects described signal output part (Vout).
2. PFC current foldback circuit according to claim 1 is characterized in that: the output of described computing comparator (U1) connects its in-phase input end by a feedback resistance (R7).
3. PFC current foldback circuit according to claim 1 and 2 is characterized in that: described bias voltage and reference voltage are by a direct current power supply (+15V) conversion generation; Wherein, described DC power supply (+15V) connect a voltage stabilizing didoe (ZD1) by filter circuit (CE1, C1), generate stable voltage signal, generate described reference voltage by resistance pressure-dividing network (R4, R5), the inverting input of concatenation operation comparator (U1) on the one hand; Export described bias voltage by a resistance (R6) on the other hand, with the in-phase input end that is input to computing comparator (U1) after the described sampled voltage signal stack.
4. PFC current foldback circuit according to claim 3 is characterized in that: described sampled voltage signal is a negative voltage signal, connects the in-phase input end of described computing comparator (U1) by capacitance-resistance filter network (R2, C3).
5. PFC current foldback circuit according to claim 3 is characterized in that: the output of described computing comparator (U1) connects one+3.3V DC power supply through pull-up resistor (R8).
6. air conditioner with the described PFC current foldback circuit of claim 1, comprise signal input part (Vin), signal output part (Vout), computing comparator (U1) and sampling resistor (R1), it is characterized in that: after the system power of air conditioner changes current signal into voltage signal by sampling resistor (R1), by described signal input part (Vin) input, so with bias voltage stack after be connected to the in-phase input end of described computing comparator (U1); The inverting input of described computing comparator (U1) connects reference voltage, output is by the control circuit of described signal output part (Vout) connection air conditioner, and described control circuit is according to the operating state of pfc circuit in the voltage signal control of Electric potentials air-conditioning system that receives.
7. air conditioner according to claim 6 is characterized in that: the output of described computing comparator (U1) connects its in-phase input end by a feedback resistance (R7).
8. according to claim 6 or 7 described air conditioners, it is characterized in that: described bias voltage and reference voltage are by a direct current power supply (+15V) conversion generation; Wherein, described DC power supply (+15V) connect a voltage stabilizing didoe (ZD1) by filter circuit (CE1, C1), generate stable voltage signal, generate described reference voltage by resistance pressure-dividing network (R4, R5), the inverting input of concatenation operation comparator (U1) on the one hand; Export described bias voltage by a resistance (R6) on the other hand, with the in-phase input end that is input to computing comparator (U1) after the described sampled voltage signal stack.
9. air conditioner according to claim 8 is characterized in that: described sampled voltage signal is a negative voltage signal, connects the in-phase input end of described computing comparator (U1) by capacitance-resistance filter network (R2, C3).
10. air conditioner according to claim 8 is characterized in that: the output of described computing comparator (U1) connects one+3.3V DC power supply through pull-up resistor (R8).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2006201618407U CN200994060Y (en) | 2006-12-22 | 2006-12-22 | PFC overcurrent protection circuit and air conditioner with same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2006201618407U CN200994060Y (en) | 2006-12-22 | 2006-12-22 | PFC overcurrent protection circuit and air conditioner with same |
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| CN200994060Y true CN200994060Y (en) | 2007-12-19 |
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| CNU2006201618407U Expired - Fee Related CN200994060Y (en) | 2006-12-22 | 2006-12-22 | PFC overcurrent protection circuit and air conditioner with same |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108306400A (en) * | 2018-03-22 | 2018-07-20 | 广州云阳电子科技有限公司 | A kind of detectable Cross prevention battery pack connects and starts the intelligent charger and its implementation of charging automatically |
| CN112165075A (en) * | 2020-09-22 | 2021-01-01 | 郑州嘉晨电器有限公司 | Overcurrent protection circuit |
| CN113685963A (en) * | 2020-05-19 | 2021-11-23 | 海信（山东）空调有限公司 | Air conditioner purification control circuit and air conditioner |
-
2006
- 2006-12-22 CN CNU2006201618407U patent/CN200994060Y/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108306400A (en) * | 2018-03-22 | 2018-07-20 | 广州云阳电子科技有限公司 | A kind of detectable Cross prevention battery pack connects and starts the intelligent charger and its implementation of charging automatically |
| CN113685963A (en) * | 2020-05-19 | 2021-11-23 | 海信（山东）空调有限公司 | Air conditioner purification control circuit and air conditioner |
| CN113685963B (en) * | 2020-05-19 | 2023-08-04 | 海信空调有限公司 | Air conditioner purification control circuit and air conditioner |
| CN112165075A (en) * | 2020-09-22 | 2021-01-01 | 郑州嘉晨电器有限公司 | Overcurrent protection circuit |
| CN112165075B (en) * | 2020-09-22 | 2021-08-24 | 郑州嘉晨电器有限公司 | Overcurrent protection circuit |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| ASS | Succession or assignment of patent right |
Owner name: HISENSE( SHANDONG ) AIR CONDITIONING CO., LTD. Free format text: FORMER OWNER: QINGDAO HISENSE AIR CONDITIONING CO. Effective date: 20080425 |
|
| C41 | Transfer of patent application or patent right or utility model | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20080425 Address after: Shandong City, Qingdao province Jiangxi City Road 11, zip code: 266071 Patentee after: Hisense (Shandong) Air-Conditioning Co., Ltd. Address before: Shandong City, Qingdao province Jiangxi City Road 11, zip code: 266071 Patentee before: Haisense Air Conditioner Co., Ltd., Qingdao |
|
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20071219 Termination date: 20121222 |