CN2884639Y - Overheat protection circuit - Google Patents
Overheat protection circuit Download PDFInfo
- Publication number
- CN2884639Y CN2884639Y CN 200520078171 CN200520078171U CN2884639Y CN 2884639 Y CN2884639 Y CN 2884639Y CN 200520078171 CN200520078171 CN 200520078171 CN 200520078171 U CN200520078171 U CN 200520078171U CN 2884639 Y CN2884639 Y CN 2884639Y
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- CN
- China
- Prior art keywords
- transformer
- thyristor
- circuit
- temperature
- drive circuit
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- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
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Abstract
The utility model provides an over-temperature protection circuit, and is used in the drive circuit in transformers and to pull down the output voltage of the driver circuit to the ground when the temperature is too high, so that the transformer stops working. The over-temperature protection circuit mainly consists of a thermistor and a thyristor, based on the temperature characteristics of the thermistor and the switching characteristics of the thyristor, when the temperature exceeds the critical point, the thyristor conducts and drives the circuit output voltage to drop down to the ground, and the transformer stops working until the temperature drops to the critical point below and then triggers the drive circuit, to enable it to provide the transformer with the drive voltage again. When the temperature of the transformer is too high for the utility model, the output voltage of the drive circuit is dropped down to the ground, so that the transformer stops working, thereby avoiding the transformer from being burnt due to too high temperature.
Description
[technical field]
The relevant a kind of thermal-shutdown circuit of the utility model, the thermal-shutdown circuit on particularly a kind of drive circuit that is applied to transformer.
[background technology]
At present, inverter (Inverter) circuit can be used transformer mostly, but industry is not all monitored the temperature of transformer.When the transformer operate as normal, its temperature can be very not high, generally can not surpass critical temperature; And occur when unusual when transformer, temperature can raise along speed, will directly influence the component parameters that distributes around it; and because inverter does not have thermal-shutdown circuit; the temperature of transformer can continue to raise, and can burn out transformer and printed circuit board (PCB) when reaching certain temperature, also can be on fire when serious.What is more, and when the transformer temperature was too high, inverter still was in normal operating conditions, as untimely eliminating hidden danger, the transformer temperature can continue to raise, and will cause the situation that transformer burns, the casing burning is deceived, and finally can cause the complete machine paralysis of notebook computer electronic installations such as (Notebook).And transformer group is loaded in the casing, in case occur damaging phenomenon, dismounting and change is also very inconvenient.
In view of this, be necessary in fact to develop a kind of temperature voltage of drive circuit that down-drawable provides driving voltage for this transformer when too high to the thermal-shutdown circuit on ground, thereby avoid because of the too high the problems referred to above that cause of transformer temperature in transformer.
[summary of the invention]
Therefore; the purpose of this utility model is to provide a kind of thermal-shutdown circuit, is applied on the drive circuit of transformer, and the output voltage that is used to temperature drop-down this drive circuit when too high is to ground; this transformer is quit work, thereby avoid too high and the situation that transformer burns out of Yin Wendu.
For reaching above-mentioned purpose; thermal-shutdown circuit of the present utility model is applied on the drive circuit of transformer; the output voltage that is used to temperature drop-down this drive circuit when too high is to ground; it mainly is the other thermal-shutdown circuit that connects on this drive circuit; the input voltage of the power input of this drive circuit is controlled the output voltage of the drive output of this drive circuit; and this thermal-shutdown circuit is by a reference voltage source; one thyristor; one thermistor; one resistance and an earth terminal are formed; this reference voltage source positive pole is connected to the power input of this drive circuit and the anode of thyristor respectively; and the minus earth of this thyristor forms DC loop; the control utmost point of this thyristor is connected in the node between this thermistor and this resistance; and this resistance other end ground connection, and the other end of this thermistor is connected to system power supply.
Compared to prior art; the utility model is by the other thermal-shutdown circuit that connects on drive circuit; utilize the temperature characterisitic of the thermistor in this thermal-shutdown circuit and the switching characteristic of thyristor; when temperature was too high, the output voltage of drop-down this drive circuit was to ground, and then this transformer quits work; descend until temperature; trigger this drive circuit again, make it, thereby avoid Yin Wendu too high and the situation that transformer burns out occurs again for this transformer provides driving voltage.
[description of drawings]
Fig. 1 is the composition frame chart that thermal-shutdown circuit of the present utility model is connected with drive circuit.
Fig. 2 A is the circuit diagram that thermal-shutdown circuit of the present utility model is connected with drive circuit.
Fig. 2 B is the circuit symbol of thyristor.
Fig. 3 B is the structural representation of thyristor.
[embodiment]
As shown in Figure 1; composition frame chart for thermal-shutdown circuit of the present utility model; as shown in the figure; thermal-shutdown circuit 1 of the present utility model is applied on the drive circuit 2 of transformer 3; wherein, this transformer 3 is a high potential in order to promote electronegative potential, and these drive circuit 2 usefulness think that this transformer 3 provides driving voltage; thermal-shutdown circuit 1 is in order to when the temperature of this transformer 3 is too high, and the output voltage of drop-down this drive circuit 2 is to ground.
See also Fig. 2 A; the circuit diagram that is connected with drive circuit for thermal-shutdown circuit of the present utility model; the input voltage of the power input of this drive circuit 2 is controlled the output voltage of its drive output; in the present embodiment; this drive circuit 2 is an integrated circuit (IC) (Integrated Circuit); its power input and drive output are respectively the reference voltage source pin Pin15 of this integrated circuit (IC) and drive output pin Pin8; and this reference voltage source pin Pin15 is provided by the extraneous voltage (being detailed later) that provides; and this driving output pin Pin8 provides driving voltage for transformer 3, makes this transformer 3 runnings.Again, this thermal-shutdown circuit 1 comprises a reference voltage source V
REF, a thyristor V, a thermistor RT, a resistance R and earth terminal, wherein, reference voltage source V
REFPositive pole be connected to the anode A of above-mentioned reference voltage source pin Pin15 and thyristor V, and the negative electrode K ground connection of this thyristor V, form DC loop, and the control utmost point G of this thyristor V is connected in the node between thermistor RT and the resistance R, and this resistance R other end ground connection, and the other end of this thermistor RT is connected to system power supply (not illustrating among the figure).Wherein, this thermistor RT is close to this transformer 3, responds to the variations in temperature of this transformer 3.
Shown in Fig. 3 A and 3B, circuit symbol and structural representation for thyristor, below briefly introduce the operation principle of thyristor V, thyristor V is a kind of four layers of PNPN structure devices, it has a PN junction in any direction at least, make it can on either direction, block electric current, thus thyristor V also be called controllable silicon (Silicon Controlled Rectifier, SCR).Have only when between the anode A of thyristor V and the negative electrode K to be added with forward voltage, control simultaneously when adding the forward trigger voltage between utmost point G and negative electrode K, the conducting that can be triggered presents the low-resistance conducting state between anode A, the negative electrode K at this moment.After this thyristor V conducting, even control utmost point G loses conducting voltage, as long as still keep forward voltage between anode A and the negative electrode K, thyristor V keeps the low-resistance conducting state.Have only when polarity of voltage changes between a removal anode A or anode A, the negative electrode K, thyristor V just is converted to the high resistant cut-off state by the low-resistance conducting state.And in a single day thyristor V ends, and has both made between anode A and the negative electrode K and has added forward voltage again, still needs to add that the forward trigger voltage can conducting between control utmost point G and negative electrode K.
When transformer 3 was in normal operating conditions, its temperature was lower than a critical point, reference voltage source V
REFBe respectively thermal-shutdown circuit 1 and drive circuit 2 provides voltage; wherein; drive circuit 2 also provides driving voltage for transformer 3 under the control of thermal-shutdown circuit 1; the voltage at resistance R two ends; that is; the control utmost point G of thyristor V and the pressure drop between the negative electrode K are less than the forward trigger voltage of thyristor V, and then thyristor V is in the high resistant cut-off state.When the temperature of this transformer 3 raises gradually, the resistance of being close to the thermistor RT of this transformer 3 reduces with the rising of temperature, thereby make the voltage at this thermistor RT two ends descend, and then make the voltage at resistance R two ends, the control utmost point G and the pressure drop between the negative electrode K that are thyristor V are risen, temperature postcritical until transformer 3, the control utmost point G of thyristor V and the pressure drop between the negative electrode K surpass the forward trigger voltage of this thyristor V, this thyristor V triggering and conducting then, present the low-resistance conducting state, the voltage of anode A is pulled down to ground, then reference voltage source V
REFAnodal voltage also is pulled down to ground, and integrated circuit (IC) is because of the zero input voltage of reference voltage source pin Pin15 quits work, and the no driving voltage that then drives output pin Pin8 offers transformer 3, and transformer 3 also decommissions.Then, the temperature of transformer 3 descends, and the resistance of thermistor RT rises, drop to below the critical point until the temperature of this transformer 3, this moment restarting systems, then reference voltage source V
REFFor this drive circuit 2 provides voltage with this thermal-shutdown circuit 1; and drive circuit 2 provides driving voltage for transformer 3; the voltage at the resistance R two ends of thermal-shutdown circuit 1; that is; be the control utmost point G of thyristor V and the pressure drop between the negative electrode K forward trigger voltage less than thyristor V, thyristor V is in the high resistant cut-off state.
Compared to prior art; the utility model is by the other thermal-shutdown circuit 1 that connects on drive circuit 2; utilize the temperature characterisitic of the thermistor RT in this thermal-shutdown circuit 1 and the switching characteristic of thyristor V; when temperature surpasses zero point; thyristor V conducting; these drive circuit 2 output voltages also are pulled down to ground; then this transformer 3 quits work; drop to below the critical point until temperature; trigger this drive circuit 2 again; make it again for this transformer 3 provides driving voltage, thereby avoid Yin Wendu too high and the situation that transformer burns out occurs.
Claims (4)
1; a kind of thermal-shutdown circuit; being applied to provides on the drive circuit of driving voltage for a transformer; driving voltage in order to drop-down this drive circuit when temperature is too high; it is characterized in that: comprise a thermistor; one thyristor; one reference voltage source and a grounding through resistance end; wherein; this reference voltage source positive pole is connected to the power input of this drive circuit and the anode of thyristor respectively; and the minus earth of this thyristor; the control utmost point of this thyristor is connected to an end of this thermistor; the other end of this thermistor is connected to system power supply; and the control utmost point of this thyristor also is connected in an end of this resistance, and this resistance other end ground connection.
2, thermal-shutdown circuit as claimed in claim 1; it is characterized in that: this drive circuit comprises that a power input and is subjected to the drive output of this power input control; and this power input connects the positive pole of reference voltage source, and this drive output connects above-mentioned transformer.
3, thermal-shutdown circuit as claimed in claim 2 is characterized in that: this drive circuit is an integrated circuit.
4, thermal-shutdown circuit as claimed in claim 1 is characterized in that: this thermistor is close to this transformer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200520078171 CN2884639Y (en) | 2005-11-25 | 2005-11-25 | Overheat protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200520078171 CN2884639Y (en) | 2005-11-25 | 2005-11-25 | Overheat protection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN2884639Y true CN2884639Y (en) | 2007-03-28 |
Family
ID=37957691
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 200520078171 Expired - Fee Related CN2884639Y (en) | 2005-11-25 | 2005-11-25 | Overheat protection circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN2884639Y (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102593792A (en) * | 2012-03-02 | 2012-07-18 | 常州特种变压器有限公司 | Built-in circuit breaker for oil-immersed transformer |
| CN103248347A (en) * | 2012-02-08 | 2013-08-14 | 英飞凌科技股份有限公司 | over temperature protection transistor |
| CN104167928A (en) * | 2013-05-15 | 2014-11-26 | 海洋王（东莞）照明科技有限公司 | Power supply circuit and power supply apparatus |
| CN105610124A (en) * | 2014-11-18 | 2016-05-25 | 施耐德电气美国股份有限公司 | EVSE handle with automatic thermal shut down by NTC to ground |
| CN105841831A (en) * | 2015-02-03 | 2016-08-10 | 精工半导体有限公司 | Overheat detection circuit and power supply apparatus |
-
2005
- 2005-11-25 CN CN 200520078171 patent/CN2884639Y/en not_active Expired - Fee Related
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103248347A (en) * | 2012-02-08 | 2013-08-14 | 英飞凌科技股份有限公司 | over temperature protection transistor |
| CN103248347B (en) * | 2012-02-08 | 2016-09-28 | 英飞凌科技股份有限公司 | Overheat protector transistor |
| CN102593792A (en) * | 2012-03-02 | 2012-07-18 | 常州特种变压器有限公司 | Built-in circuit breaker for oil-immersed transformer |
| CN104167928A (en) * | 2013-05-15 | 2014-11-26 | 海洋王（东莞）照明科技有限公司 | Power supply circuit and power supply apparatus |
| CN104167928B (en) * | 2013-05-15 | 2017-05-03 | 海洋王（东莞）照明科技有限公司 | Power supply circuit and power supply apparatus |
| CN105610124A (en) * | 2014-11-18 | 2016-05-25 | 施耐德电气美国股份有限公司 | EVSE handle with automatic thermal shut down by NTC to ground |
| EP3025902B1 (en) * | 2014-11-18 | 2023-05-17 | Schneider Electric USA, Inc. | Evse handle with automatic thermal shut down by ntc to ground |
| CN105841831A (en) * | 2015-02-03 | 2016-08-10 | 精工半导体有限公司 | Overheat detection circuit and power supply apparatus |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |