CN207380129U - A kind of excess temperature overvoltage crowbar - Google Patents
A kind of excess temperature overvoltage crowbar Download PDFInfo
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- CN207380129U CN207380129U CN201720387016.1U CN201720387016U CN207380129U CN 207380129 U CN207380129 U CN 207380129U CN 201720387016 U CN201720387016 U CN 201720387016U CN 207380129 U CN207380129 U CN 207380129U
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- voltage
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Abstract
The utility model provides a kind of excess temperature overvoltage crowbar, including power input, control switch 1, control switch 2, voltage check device, temperature-detecting device, power output end；What power input inputted is the positive-negative power input of DC power supply；Control switch 1 is opened or closed by the height of the voltage check device interpretation input voltage；Control switch 2 is the opening and closing for controlling power cathode；Whether voltage check device detection input voltage exceeds highest threshold value；Whether the temperature of temperature-detecting device detection pcb board circuit exceeds maximum temperature；Power output apparatus exports the positive-negative power of DC power supply.
Description
Technical field
The utility model is related to a kind of electronic circuit field more particularly to a kind of excess temperature overvoltage crowbars.
Background technology
At present, the mobile power used in the market, the overwhelming majority are that 5V charges.But with the popularization of fast charge technology,
Fast charger can be given 5V power source charges by many users, and fast charger is usually the different voltage such as 9V/12V/20V.Soon
It is the combinations of voltages detected on D+, D- to fill, and exports different voltage.When using these underproof fast chargers, or
When with the charger of 9V voltages to 5V power source charges so that mobile power PCBA can be burned, since the failure burnt out shows
As different, it may be possible to cannot continue to charge or work on；But with the presence of a constant current, temperature is caused to live in concentrated communities rise, is burnt
Shell is ruined, some settings are on fire, and great security risk is brought to user.Quick charge for other equipment, there is also fast
Security risk caused by speed charges.
Common excess temperature overvoltage crowbar, is to add microcontroller using voltage sampling to realize, this realization method one is
It is of high cost, second is that reliability is low, because in same production technology, temperature range is narrow for the temperature range of microcontroller
Very much.
The content of the invention
The utility model in order to when solving that input voltage is excessively high and equipment internal temperature is excessively high without low cost, high reliability
Protection circuit the problem of, a kind of excess temperature overvoltage crowbar is provided.
To solve the above-mentioned problems, the technical solution adopted in the utility model is as described below：
A kind of excess temperature overvoltage crowbar, including power input, control switch 1, control switch 2, voltage check device,
Temperature-detecting device, power output end；
What the power input inputted is the positive-negative power input of DC power supply；
The control switch 1 is opened or closed by the height of the voltage check device interpretation input voltage；
The control switch 2 is the opening and closing for controlling power cathode；
Whether the voltage check device detection input voltage exceeds highest threshold value；
Whether the temperature of the temperature-detecting device detection pcb board circuit exceeds maximum temperature；
The positive-negative power of the power output apparatus output DC power supply.
Preferably, the voltage check device includes two series resistance R1、R3, the resistance R3With control switch 1 simultaneously
Connection；The temperature-detecting device includes posive temperature coefficient thermistor RT1With resistance R2, the voltage check device and the temperature
It is in parallel to spend detection device；The control switch 1 and control switch 2 are respectively field-effect tube Q1With field-effect tube Q2。
Preferably, field-effect tube Q1Both end voltage is higher than conducting voltage, that is, becomes conducting state, so as to reduce field-effect tube
Q2G pole tensions, make field-effect tube Q2Switch to closed state, so as to close power supply output；Field-effect tube Q1Both end voltage, which is less than, to be led
Be powered pressure, as cut-off state, field-effect tube Q2Conducting, power supply normally export.
Preferably, as temperature raises, posive temperature coefficient thermistor RT1Resistance value increase, so as to reduce field-effect tube Q2
G pole tensions, make Q2Switch to closed state, so as to close power supply output.
Preferably, the resistance R1, resistance R3Resistance value, the input voltage and the field-effect tube Q1Conducting voltage
Between meet：[R3/(R1+R3)] * input voltages<The field-effect tube Q1Conducting voltage when, the field-effect tube Q1Conducting
Voltage is cut-off state；When input voltage >=highest threshold value, the field-effect tube Q1Conducting.
Preferably, when reaching the maximum temperature, the resistance RT1Resistance value and the resistance R2, the input voltage,
The field-effect tube Q2Conducting voltage between meet：[R2/ (RT1+R2)] * input voltages=field-effect tube Q2Cut-off
Voltage.
Preferably, the field-effect tube Q2S poles connect the input terminal of power cathode, D poles connect the output of power cathode.
Preferably, the field-effect tube Q1, field-effect tube Q2G pole tensions or grid voltage according to the highest threshold value and
Maximum temperature adjusts.
Preferably, the control switch 1 and/or control switch 2 are switching transistor or metal-oxide-semiconductor.
Preferably, the control switch 1 and/or control switch 2 are PMOS tube, and the PMOS tube controls positive pole；Or
Control switch 1 and/or control switch 2 are NMOS tubes, and the NMOS tube controls power cathode.
The beneficial effects of the utility model are：A kind of excess temperature overvoltage crowbar is provided, does not have software and monolithic in circuit
Machine, by the closure that temperature-detecting device and voltage check device control circuit switch, overall cost is than common excess temperature overvoltage
Protect circuit low；Because without software, reliability also will height.
Description of the drawings
Fig. 1 is that the circuit of the utility model embodiment realizes block diagram.
Fig. 2 is the circuit realization principle figure of the utility model embodiment.
Fig. 3 is the another circuit realization principle figure of the utility model embodiment.
Specific embodiment
The utility model is described in detail by specific embodiment below in conjunction with the accompanying drawings, for a better understanding of this
Utility model, but following embodiments are not intended to limit the scope of the utility model.In addition, it is necessary to illustrate, institute in following embodiments
The diagram of offer only illustrates the basic conception of the utility model in a schematic way, in attached drawing only display with it is related in the utility model
Component rather than component count, shape and size during according to actual implementation draw, the shape of each component, number during actual implementation
Amount and ratio can be a kind of random change, and its assembly layout form may also be increasingly complex.
Embodiment 1
As shown in Figure 1, a kind of excess temperature overvoltage crowbar, including power input, control switch 1, control switch 2, electricity
Press detection device, temperature-detecting device, power output end；
What the power input inputted is the positive-negative power input of DC power supply；
The control switch 1 is opened or closed by the height of the voltage check device interpretation input voltage；
The control switch 2 is the opening and closing for controlling power cathode；
Whether the voltage check device detection input voltage exceeds highest threshold value；
Whether the temperature of the temperature-detecting device detection pcb board circuit exceeds maximum temperature；
The positive-negative power of the power output apparatus output DC power supply.
The maximum temperature and highest threshold value can adjust as needed.
The field-effect tube Q1, field-effect tube Q2G pole tensions or grid voltage according to the highest threshold value and maximum temperature
Adjustment.
As shown in Fig. 2, the power input is USB, the voltage check device includes two series resistance R1、R3,
The resistance R3It is in parallel with control switch 1；The temperature-detecting device includes posive temperature coefficient thermistor RT1And R2, the electricity
Press detection device and the temperature-detecting device in parallel；The control switch 1 and control switch 2 are respectively field-effect tube Q1And Q2。
When normal voltage inputs, voltage is when within the scope of setting, field-effect tube Q2Conducting, power supply from input through to
Output device.
The principle of overvoltage protection：When overtension, field-effect tube Q1Switching tube from cut-off state, be transformed into conducting shape
State, so as to by field-effect tube Q2G pole tensions move to 0.1V volt within because at this time Q2 field-effect tube switch close voltage will
More than 0.7V (conducting voltage of different field-effect tube is different, can adjust as needed), so Q2From conducting state, turn
Become closed state, so as to close power supply output, have the function that overvoltage protection.
The principle of overheat protector：RT herein1For posistor, positive temperature system thermistor, temperature is higher, electricity
It is bigger to hinder resistance value；So when the temperature increases, field-effect tube Q2G pole tensions just reduce, when temperature is increased to, make field-effect
Pipe Q2G pole tensions less than 0.7V (different field-effect tube, blanking voltage different) when, Q2Cut-off, so as to close the defeated of power supply
Go out, have the function that overheat protector.Using the conduction threshold of field-effect tube, opening and the cut-off of circuit are realized, because field-effect
Pipe, be generally all built-in with diode, grid protected, so, the connection method of Q2, can only S poles connect the input that power supply is born
End, D poles connect the output of power cathode, if reversal connection, this circuit is invalid.
For resistance R1、R3Selection method：If Q1Conducting voltage be 1.2V, it is desired to input voltage be higher than 6.0V when just
It plays a protective role, then R1、R3Selection method meet equation below： [R3/(R1+R3)] * 6.0=1.2 are by this formula
Simplify, can but obtain R1=4*R3；If R3=10 kilo-ohms, then R1=40 kilo-ohms；Above-mentioned value is substituted into formula：
[10/ (10+40)] * 5=1.0V, less than Q1Conducting voltage, so as to usually Q1Closed state is handled, power supply normally exports.
For thermistor RT1And R2Selection method：If the voltage that we normally input is 5V, Q2Conducting voltage
For 1.2V, blanking voltage 1.0V, RT1、R2Equation below must be met：[R2/ (RT1+R2)] * 5.0=1.0；From in RT1=4*
R2.If：R2=20 kilo-ohms；It is 90 degree that if we, which set overheat protector temperature, then when should select 90 degree, resistance value is 80 kilo-ohms
Positive temperature coefficient thermistor.If thermosensitive resistance is during 25 DEG C of room temperature：40 kilo-ohms, then [20/ (40+20)] * 5=
1.67V, more than 1.2V, Q2Conducting, there is power supply output；When temperature is 90 degree, then [20/ (80+20)] * 5=1V, Q2 end,
Non-transformer exports, so as to have the function that overheat protector.
The advantages of the present embodiment excess temperature overvoltage crowbar is that cost is cheap；Common overvoltage protection can be protected with self- recoverage
Dangerous silk adds zener diode, 0.25+0.05=0.30 members, as long as resistance adds a triode on the protection circuit two of the present embodiment
=0.002*2+0.03=0.034 members.
The present embodiment excess temperature overvoltage crowbar it is a further advantage that overvoltage protection does not generate heat；In the prior art, use
PTC thermistor and zener diode control circuit, when electric current is excessive or when the temperature is excessively high, electricity is reduced by PTC thermistors
Stream；When overtension, excess voltage is absorbed using zener diode, while electric current increases, temperature rise, PTC thermistor
Resistance value raises, and reaches pressure stabilization function.But when overtension, zener diode can generate heat, and voltage is higher, and fever is more serious,
There are security risks.
The temperature protection threshold value of the present embodiment excess temperature overvoltage crowbar, can be according to different product usage scenario not
Together, different temperature protection scopes is set, it is inexpensive and easy to use.
The present embodiment excess temperature overvoltage crowbar without software and microcontroller, overall cost is than common excess temperature overvoltage
Protect circuit low, because without software, reliability also will height.
As shown in figure 3, in the alternative embodiments of the present embodiment, the control switch 1 and/or control switch 2 are PMOS
Pipe, the PMOS tube are used for controlling positive pole, and temperature-detecting device includes negative tempperature coefficient thermistor RT at this time2。
In other alternative embodiments of the present embodiment, the control switch 1 and/or control switch 2 are switching transistor
Or NMOS tube.It should be noted that by the use of triode as switch control pipe, triode has magnification region, it is not easy to realize constant temperature control
System；The NMOS tube controls power cathode.
The above content is combine specific preferred embodiment further detailed description of the utility model, it is impossible to
Assert that the specific implementation of the utility model is confined to these explanations.For those skilled in the art of the present invention
For, without departing from the concept of the premise utility, several equivalent substitute or obvious modifications, and performance can also be made
Or purposes is identical, should all be considered as belonging to the scope of protection of the utility model.
Claims (10)
1. a kind of excess temperature overvoltage crowbar, which is characterized in that including power input, control switch 1, control switch 2, voltage
Detection device, temperature-detecting device, power output end；
What the power input inputted is the positive-negative power input of DC power supply；
The control switch 1 is opened or closed by the height of the voltage check device interpretation input voltage；
The control switch 2 is the opening and closing for controlling power cathode；
Whether the voltage check device detection input voltage exceeds highest threshold value；
Whether the temperature of the temperature-detecting device detection pcb board circuit exceeds maximum temperature；
The positive-negative power of the power output apparatus output DC power supply.
2. excess temperature overvoltage crowbar as described in claim 1, which is characterized in that the voltage check device includes two strings
Join resistance R1、R3, the resistance R3It is in parallel with control switch 1；The temperature-detecting device includes posive temperature coefficient thermistor
RT1With resistance R2, the voltage check device and the temperature-detecting device are in parallel；2 points of the control switch 1 and control switch
It Wei not field-effect tube Q1With field-effect tube Q2。
3. excess temperature overvoltage crowbar as claimed in claim 2, which is characterized in that field-effect tube Q1Both end voltage is higher than conducting
Voltage becomes conducting state, so as to reduce field-effect tube Q2G pole tensions, make Q2Switch to closed state, so as to close power supply
Output；Field-effect tube Q1Both end voltage is less than conducting voltage, as cut-off state, field-effect tube Q2Conducting, power supply normally export.
4. excess temperature overvoltage crowbar as claimed in claim 2, which is characterized in that as temperature raises, positive temperature coefficient heat
Quick resistance RT1Resistance value increase, so as to reduce field-effect tube Q2G pole tensions, make Q2Switch to closed state, so as to close power supply
Output.
5. excess temperature overvoltage crowbar as claimed in claim 2, which is characterized in that the resistance R1, resistance R3Resistance value, institute
State input voltage and the field-effect tube Q1Conducting voltage between meet：[R3/(R1+R3)] * input voltages<The field-effect
Pipe Q1Conducting voltage when, the field-effect tube Q1Conducting voltage be cut-off state；When input voltage >=highest threshold value, institute
State field-effect tube Q1Conducting.
6. excess temperature overvoltage crowbar as claimed in claim 2, which is characterized in that when reaching the maximum temperature, the electricity
Hinder RT1Resistance value and the resistance R2, the input voltage, the field-effect tube Q2Conducting voltage between meet：[R2/(RT1
+ R2)] * input voltages=field-effect tube Q2Blanking voltage.
7. excess temperature overvoltage crowbar as claimed in claim 2, which is characterized in that the field-effect tube Q2S poles connect power supply and bear
The input terminal of pole, D poles connect the output of power cathode.
8. excess temperature overvoltage crowbar as claimed in claim 2, which is characterized in that the field-effect tube Q1, field-effect tube Q2's
G pole tensions or grid voltage are adjusted according to the highest threshold value and maximum temperature.
9. excess temperature overvoltage crowbar as described in claim 1, which is characterized in that the control switch 1 and/or control switch
2 be switching transistor or metal-oxide-semiconductor.
10. excess temperature overvoltage crowbar as claimed in claim 9, which is characterized in that the control switch 1 and/or control are opened
It is PMOS tube to close 2, and the PMOS tube controls positive pole；Or control switch 1 and/or control switch 2 are NMOS tubes, the NMOS
Management and control power cathode.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201720387016.1U CN207380129U (en) | 2017-04-13 | 2017-04-13 | A kind of excess temperature overvoltage crowbar |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201720387016.1U CN207380129U (en) | 2017-04-13 | 2017-04-13 | A kind of excess temperature overvoltage crowbar |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN207380129U true CN207380129U (en) | 2018-05-18 |
Family
ID=62298410
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201720387016.1U Active CN207380129U (en) | 2017-04-13 | 2017-04-13 | A kind of excess temperature overvoltage crowbar |
Country Status (1)
| Country | Link |
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| CN (1) | CN207380129U (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108303580A (en) * | 2017-04-13 | 2018-07-20 | 深圳市三诺电子有限公司 | A kind of excess temperature overvoltage crowbar |
| CN108988293A (en) * | 2018-07-27 | 2018-12-11 | 南昌黑鲨科技有限公司 | Thermal-shutdown circuit and data line with it |
| CN108988292A (en) * | 2018-07-27 | 2018-12-11 | 南昌黑鲨科技有限公司 | Thermal-shutdown circuit and data line with it |
| CN116707501A (en) * | 2023-08-03 | 2023-09-05 | 无锡市稳先微电子有限公司 | Intelligent electronic switch, integrated circuit chip, chip product and automobile |
-
2017
- 2017-04-13 CN CN201720387016.1U patent/CN207380129U/en active Active
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108303580A (en) * | 2017-04-13 | 2018-07-20 | 深圳市三诺电子有限公司 | A kind of excess temperature overvoltage crowbar |
| CN108988293A (en) * | 2018-07-27 | 2018-12-11 | 南昌黑鲨科技有限公司 | Thermal-shutdown circuit and data line with it |
| CN108988292A (en) * | 2018-07-27 | 2018-12-11 | 南昌黑鲨科技有限公司 | Thermal-shutdown circuit and data line with it |
| CN108988293B (en) * | 2018-07-27 | 2020-06-02 | 南昌黑鲨科技有限公司 | Over-temperature protection circuit and data line with same |
| CN116707501A (en) * | 2023-08-03 | 2023-09-05 | 无锡市稳先微电子有限公司 | Intelligent electronic switch, integrated circuit chip, chip product and automobile |
| CN116707501B (en) * | 2023-08-03 | 2023-10-31 | 无锡市稳先微电子有限公司 | Intelligent electronic switch, integrated circuit chip, chip product and automobile |
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