CN201336564Y - Overcurrent protection device - Google Patents
Overcurrent protection device Download PDFInfo
- Publication number
- CN201336564Y CN201336564Y CNU2008201576899U CN200820157689U CN201336564Y CN 201336564 Y CN201336564 Y CN 201336564Y CN U2008201576899 U CNU2008201576899 U CN U2008201576899U CN 200820157689 U CN200820157689 U CN 200820157689U CN 201336564 Y CN201336564 Y CN 201336564Y
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- voltage
- protective device
- trigger
- overcurrent protective
- current
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Abstract
The utility model provides an overcurrent protection device, which is used in an active power factor correction circuit. The overcurrent protection device comprises a current/voltage converter used for receiving a system current and converts the system current to a voltage signal; and the overcurrent protection device also comprises a voltage compensator for compensating the voltage signal and at least a trigger which is connected with the current/voltage converter. The overcurrent protection device can provide higher precision after receiving the small-amplitude signal, and can prevent the circuit damage caused by periodic action.
Description
Technical field
The utility model relates to a kind of overcurrent protective device, particularly a kind of overcurrent protective device that relates to APFC.
Background technology
APFC of the prior art (Power Factor Correction; PFC) current foldback circuit adopts Direct Sampling method relatively more; faint useful signal is directly inputted in the comparator; for example; when sampling resistor is 0.02 ohm; input current is 20 ampere-hours, and the magnitude of voltage that sampling obtains is 0.4 volt only, and promptly signal amplitude is very little.
Corresponding to little signal amplitude like this, the reference voltage signal of a low amplitude value must be provided ordinatedly, whole current foldback circuit can normally be played a role.But because the existence of comparator input capacitance; make that the protective circuit reaction time is long, therefore can't reach the purpose of quick protection, and because the dispersiveness of device makes that circuit can't be according to the working point work of setting; thereby cause protecting precision low, even serious problems such as faulty operation.
In addition; if the overcurrent factor exists always; protective current will constantly cause the shutoff or the unlatching of circuit system, and periodically action all can produce impact significantly to protective circuit and circuit system so constantly, and consequent current stress is easy to make relevant components and parts to damage.
The utility model content
The purpose of this utility model provides a kind of overcurrent protective device; be applied in the APFC; it even also can improve higher precision when the signal of receiving by a small margin, and can avoid the circuit of periodically action generation to damage compared to existing technologies.
Overcurrent protective device described in the utility model, be applied in the APFC, described overcurrent protective device comprises a current/voltage converter, be used to receive a system power and be converted into a voltage signal, described overcurrent protective device also comprises: voltage compensator, in order to compensate described voltage signal; And at least one trigger, be connected to described current/voltage converter.
According to overcurrent protective device described in the utility model, wherein, also has a voltage comparator between described current/voltage converter and the described at least one trigger.Described voltage signal is connected to the in-phase input end of described voltage comparator, and the inverting input of described voltage comparator connects a reference voltage.
According to overcurrent protective device described in the utility model, wherein, described current/voltage converter is a sampling resistor.
According to overcurrent protective device described in the utility model, wherein, described trigger comprises a monostable trigger and a bistable trigger, and described trigger is the DQ trigger.
Overcurrent protective device of the present utility model can be applied to have low cost, high efficiency and high-precision advantage in the Circuits System that detected signal is a small-signal, has overcome many drawbacks of prior art.
Description of drawings
To the description of an embodiment of the present utility model, can further understand its practical novel purpose, specific structural features and advantage by following in conjunction with its accompanying drawing.Wherein, accompanying drawing is:
Fig. 1 is the block diagram of the overcurrent protective device of a preferred embodiment of the present utility model.
Embodiment
Below with reference to embodiment overcurrent protective device of the present utility model is described in further detail.
Seeing also Fig. 1, is the block diagram of the overcurrent protective device 1 of a preferred embodiment as shown in the figure, is applied in the APFC, and described overcurrent protective device 1 comprises current/voltage converter 10 and voltage comparator 12 at least.In the present embodiment, described current/voltage converter 10 can be sampling resistor, and described system power is flowed through described sampling resistor to realize the conversion of electric current to voltage.
When system power flow through described current/voltage converter 10 and be converted to voltage signal after, be connected to an end of described voltage comparator 12 again, and the other end of described voltage comparator 12 connects reference voltage, and the output of described voltage comparator 12 is connected to its input by feedback resistance.In the present embodiment, described voltage signal is connected to the in-phase input end of described voltage comparator 12, and described reference voltage is connected to the inverting input of described voltage comparator 12.
Overcurrent protective device 1 described in the utility model also comprises voltage compensator 14, is connected between described current/voltage converter 10 and the described voltage comparator 12, in order to compensate described voltage signal.In the present embodiment, described voltage compensator 14 is for providing a direct current biasing voltage signal to described voltage comparator 12, and is superimposed on the described reference voltage.By bias voltage being set for overcurrent protective device 1; faint efficiently sampling signal is superimposed upon on the reference signal; thereby the working point that makes voltage comparator 12 is arranged on the higher voltage value; so not only can improve the precision of small-signal sampling; and higher voltage can be full of electricity at short notice with the input capacitance of voltage comparator 12, thereby avoided the influence of input capacitance to protective circuit reaction time and protection precision effectively.
Overcurrent protective device 1 described in the utility model also comprises at least one trigger, is connected the output of described voltage comparator 12.In the present embodiment, described trigger comprises a monostable trigger 160 and a bistable trigger 162, and described monostable trigger 160 and bistable trigger 162 are the DQ trigger.When overcurrent condition takes place at random when; realize the protection control of circuit system by described monostable trigger 160; when taking place to continue overcurrent condition; promptly after protection resets for the first time; receive second over-current signal immediately; then forbid the protection control of circuit system earlier, carry out the cut-off type protection by institute's bistable trigger 162.Only under the situation of turn-offing the input power supply, just remove this type of protection, thereby the protection system circuit is not damaged effectively.
Of particular note; overcurrent protective device of the present utility model is not limited to structure defined in the foregoing description; although the utility model is had been described in detail with reference to preferred embodiment; those of ordinary skill in the art is to be understood that; can make amendment or be equal to replacement the utility model; and not breaking away from spirit and scope of the present utility model, it all should be encompassed in the middle of the claim scope of the present utility model.
Claims (6)
1, a kind of overcurrent protective device; be applied in the APFC, described overcurrent protective device comprises a current/voltage converter, is used to receive a system power and is converted into a voltage signal; it is characterized in that described overcurrent protective device also comprises:
Voltage compensator is in order to compensate described voltage signal; And
At least one trigger is connected to described current/voltage converter.
2, overcurrent protective device according to claim 1 is characterized in that, also has a voltage comparator between described current/voltage converter and the described at least one trigger.
3, overcurrent protective device according to claim 2 is characterized in that, described voltage signal is connected to the in-phase input end of described voltage comparator, and the inverting input of described voltage comparator connects a reference voltage.
4, overcurrent protective device according to claim 1 is characterized in that, described current/voltage converter is a sampling resistor.
5, overcurrent protective device according to claim 1 is characterized in that, described trigger comprises a monostable trigger and a bistable trigger.
6, overcurrent protective device according to claim 1 is characterized in that, described trigger is the DQ trigger.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2008201576899U CN201336564Y (en) | 2008-12-23 | 2008-12-23 | Overcurrent protection device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2008201576899U CN201336564Y (en) | 2008-12-23 | 2008-12-23 | Overcurrent protection device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201336564Y true CN201336564Y (en) | 2009-10-28 |
Family
ID=41288226
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNU2008201576899U Expired - Fee Related CN201336564Y (en) | 2008-12-23 | 2008-12-23 | Overcurrent protection device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN201336564Y (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101867177A (en) * | 2010-07-02 | 2010-10-20 | 深圳市四方电气技术有限公司 | Over-voltage and over-current hardware protection circuit and DC power supply circuit |
| CN104716630A (en) * | 2013-12-12 | 2015-06-17 | 北汽福田汽车股份有限公司 | Over-voltage and over-current protection circuit for traction motor controller |
-
2008
- 2008-12-23 CN CNU2008201576899U patent/CN201336564Y/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101867177A (en) * | 2010-07-02 | 2010-10-20 | 深圳市四方电气技术有限公司 | Over-voltage and over-current hardware protection circuit and DC power supply circuit |
| CN101867177B (en) * | 2010-07-02 | 2013-03-27 | 深圳市四方电气技术有限公司 | Over-voltage and over-current hardware protection circuit and DC power supply circuit |
| CN104716630A (en) * | 2013-12-12 | 2015-06-17 | 北汽福田汽车股份有限公司 | Over-voltage and over-current protection circuit for traction motor controller |
| CN104716630B (en) * | 2013-12-12 | 2018-03-27 | 北汽福田汽车股份有限公司 | A kind of traction motor controller over-voltage over-current protection circuit |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20091028 Termination date: 20161223 |