CN204258272U - A kind of converter high accuracy thermal-shutdown circuit - Google Patents
A kind of converter high accuracy thermal-shutdown circuit Download PDFInfo
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- CN204258272U CN204258272U CN201420826903.0U CN201420826903U CN204258272U CN 204258272 U CN204258272 U CN 204258272U CN 201420826903 U CN201420826903 U CN 201420826903U CN 204258272 U CN204258272 U CN 204258272U
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Abstract
The utility model is specifically related to a kind of high accuracy thermal-shutdown circuit for interchanger, mainly comprises sample circuit, voltage stabilizing circuit, comparison circuit, switching circuit.Described sample circuit comprises thermistor NTC1, the first divider resistance R1, the second divider resistance R3, the 4th current-limiting resistance R2 and the first filter capacitor C1; Described voltage stabilizing circuit comprises pressurizer U2, the second filter capacitor C2 and the first current-limiting resistance R4; Described comparison circuit comprises comparator U1B and the second current-limiting resistance R5; Described switching circuit comprises NPN type triode Q1 and the 3rd current-limiting resistance R7.The beneficial effects of the utility model: the utility model is simple and reliable, precision is high, provide converter and input overheat protector reliably, improve the safety and stability of converter.
Description
Technical field
The utility model relates to a kind of protective circuit, is specifically related to a kind of high accuracy thermal-shutdown circuit for interchanger.
Background technology
Converter is the device that information information source sent is undertaken by certain object converting, and usually adopts PWM module to control whole power supply, ensures the value of stable output.And converter generally needs thermal-shutdown circuit to ensure the stable of circuit and safety.Present thermal-shutdown circuit more complicated, cost is high.
Utility model content
For the deficiency that prior art exists, the purpose of this utility model is to provide a kind of converter high accuracy thermal-shutdown circuit, for converter provides reliable overheat protector.
For achieving the above object, the utility model can be achieved by the following technical programs:
A kind of converter high accuracy thermal-shutdown circuit, comprising:
Sample circuit, exports sampling voltage;
Voltage stabilizing circuit, output reference voltage;
Comparison circuit, receives and compares sampling voltage and reference voltage, output level;
Switching circuit, controls its conducting and cut-off by the output level of described comparison circuit;
Described sample circuit comprises thermistor NTC1, the first divider resistance R1, the second divider resistance R3, the 4th current-limiting resistance R2 and the first filter capacitor C1, one end of described thermistor NTC1 connects voltage input end Vin+, the other end is connected in series the positive input terminal that then the first divider resistance R1 and the 4th current-limiting resistance R2 is connected to comparison circuit successively, described second divider resistance R3 one end connects the node between the first divider resistance R1 and the 4th current-limiting resistance R2, other end ground connection, described first filter capacitor C1 is in parallel with the second divider resistance R3;
Described voltage stabilizing circuit comprises pressurizer U2, the second filter capacitor C2 and the first current-limiting resistance R4, the plus earth of described pressurizer U2, its negative electrode is connected to power voltage input terminal VCC by the first current-limiting resistance R4, and described second filter capacitor C2 is in parallel with pressurizer U2;
Described comparison circuit comprises comparator U1B and the second current-limiting resistance R5, and described second current-limiting resistance R5 one end is connected to the node between voltage-stabiliser tube U2 and the first current-limiting resistance R4, and the other end is connected to the negative input end of comparator U1B;
Described switching circuit comprises NPN type triode Q1 and the 3rd current-limiting resistance R7, described 3rd current-limiting resistance R7 one end connects the output of comparator U1B, the other end connects the base stage of NPN type triode Q1, the collector electrode of described NPN type triode Q1 connects the compensation level end comp of the PWM IC of converter, the grounded emitter of described NPN type triode Q1.
In above-mentioned technical scheme; utilize comparator U1B to compare reference voltage and sampled voltage, when temperature is raised, the resistance value of thermistor NTC1 diminishes; when temperature rising makes sampled voltage be greater than the protection value of setting; comparator U1B positive input terminal voltage is greater than negative input end voltage, and comparator overturns, and exports high level; make NPN type triode conducting; be pulled down to by the COMP of PWM IC compensation pin and be less than 1V, IC turns off output, reaches the object of input overheat protector.
Further, the node between described second current-limiting resistance R5 and comparator U1B, by the first pull down resistor R9 ground connection, prevents comparator U1B misoperation.
Further, described comparison circuit also comprises the diode D1 be arranged between comparator U1B and the 3rd current-limiting resistance R7, the anode of described diode D1 connects the output of comparator U1B, its negative electrode serial connection the 3rd current-limiting resistance R7, makes the output level of comparison circuit can only one-way conduction.
Further, described comparison circuit also comprises the second pull down resistor R6 and the 4th filter capacitor C3, and one end of described second pull down resistor R6 connects the negative electrode of diode D1, other end ground connection, described 4th filter capacitor C3 is in parallel with the second pull down resistor R6, prevents comparison circuit misoperation.
Further, described switching circuit 4 also comprises the 3rd pull down resistor R8 and the 3rd filter capacitor C4, and described 3rd filter capacitor C4 one end is connected with the base stage of NPN type triode Q1, other end ground connection, described 3rd pull down resistor R8 is in parallel with the 3rd filter capacitor C4, prevents triode Q1 misoperation.
Further, described pressurizer U2 is adjustable three terminal integrated voltage stabilizer, comprises anode, negative electrode and adjustable side.
The beneficial effects of the utility model: the utility model is simple and reliable, precision is high, provide converter and input overheat protector reliably, improve the safety and stability of converter.
Accompanying drawing explanation
Fig. 1 is circuit theory schematic diagram of the present utility model.
Embodiment
Below in conjunction with accompanying drawing and embodiment, the utility model is further described:
As shown in Figure 1, converter high accuracy input thermal-shutdown circuit described in the utility model, mainly comprises sample circuit, voltage stabilizing circuit, comparison circuit and switching circuit.
Sample circuit, for exporting accurate sampling voltage, comprise thermistor NTC1, first divider resistance R1, second divider resistance R3, 4th current-limiting resistance R2 and the first filter capacitor C1, one end of described thermistor NTC1 connects voltage input end Vin+, the other end is connected in series the positive input terminal that then the first divider resistance R1 and the 4th current-limiting resistance R2 is connected to comparison circuit successively, described second divider resistance R3 one end connects the node between the first divider resistance R1 and the 4th current-limiting resistance R2, other end ground connection, described first filter capacitor C1 is in parallel with the second divider resistance R3.First filter capacitor C1 stablizes sampling voltage, prevents sampling voltage to fluctuate, and makes sampling voltage value more accurate.Vin+＝VCC/(R1+R3)/R3。
Voltage stabilizing circuit, for the 2.49V reference voltage of stable output, comprises pressurizer U2, the second filter capacitor C2 and the first current-limiting resistance R4.Preferably, pressurizer U2 selects adjustable three terminal integrated voltage stabilizer, comprises anode, negative electrode and adjustable side.The plus earth of pressurizer U2, its negative electrode is connected to power voltage input terminal VCC by the first current-limiting resistance R4, and the first current-limiting resistance R4 protects pressurizer U2, makes the operating current of pressurizer U2 within specification limit.Second filter capacitor C2 is in parallel with pressurizer U2, and stable reference voltage prevents reference voltage to fluctuate, and makes reference voltage value more accurate.
Comparison circuit, for receiving and comparing sampling voltage and reference voltage, outputs level signals, comprises comparator U1B, diode D1, the second current-limiting resistance R5, the first pull down resistor R9, the second pull down resistor R6 and the 4th filter capacitor C3.Second current-limiting resistance R5 one end is connected to the node between voltage-stabiliser tube U2 and the first current-limiting resistance R4, and the other end is connected to the negative input end of comparator U1B.Node between second current-limiting resistance R5 and comparator U1B is by the first pull down resistor R9 ground connection.The anode of diode D1 connects the output of comparator U1B, its negative electrode serial connection the 3rd current-limiting resistance R7.One end of second pull down resistor R6 connects the negative electrode of diode D1, other end ground connection.4th filter capacitor C3 is in parallel with the second pull down resistor R6.
Switching circuit, controls its conducting and cut-off by the output level of comparison circuit, comprises NPN type triode Q1, the 3rd current-limiting resistance R7, the 3rd filter capacitor C4 and the 3rd pull down resistor R8.3rd current-limiting resistance R7 one end connects the negative electrode of diode D1, and the other end connects the base stage of NPN type triode Q1.3rd filter capacitor C4 one end is connected with the base stage of NPN type triode Q1, other end ground connection, and the 3rd pull down resistor R8 is in parallel with the 3rd filter capacitor C4.The collector electrode of NPN type triode Q1 connects the compensation level end comp of the PWM IC of converter, grounded emitter.
In the present embodiment; comparator U1B compares reference voltage and sampled voltage, and when temperature is raised, the resistance value of thermistor NTC1 diminishes; when temperature rising makes sampled voltage be greater than the protection value of setting; comparator U1B positive input terminal voltage is greater than negative input end voltage (2.49V), and comparator overturns, and exports high level; make NPN type triode conducting; be pulled down to by the COMP of PWM IC compensation pin and be less than 1V, IC turns off output, reaches the object of input overheat protector.
For a person skilled in the art, according to above technical scheme and design, other various corresponding change and distortion can be made, and all these change and distortion all should belong within the protection range of the utility model claim.
Claims (6)
1. a converter high accuracy thermal-shutdown circuit, is characterized in that, comprising:
Sample circuit, exports sampling voltage;
Voltage stabilizing circuit, output reference voltage;
Comparison circuit, receives and compares sampling voltage and reference voltage, output level;
Switching circuit, controls its conducting and cut-off by the output level of described comparison circuit;
Described sample circuit comprises thermistor (NTC1), first divider resistance (R1), second divider resistance (R3), 4th current-limiting resistance (R2) and the first filter capacitor (C1), one end of described thermistor (NTC1) connects voltage input end (Vin+), the other end is connected in series the positive input terminal that the first divider resistance (R1) and the 4th current-limiting resistance (R2) are then connected to comparison circuit successively, described second divider resistance (R3) one end connects the node between the first divider resistance (R1) and the 4th current-limiting resistance (R2), other end ground connection, described first filter capacitor (C1) is in parallel with the second divider resistance (R3),
Described voltage stabilizing circuit comprises pressurizer (U2), the second filter capacitor (C2) and the first current-limiting resistance (R4), the plus earth of described pressurizer (U2), its negative electrode is connected to power voltage input terminal (VCC) by the first current-limiting resistance (R4), and described second filter capacitor (C2) is in parallel with pressurizer (U2);
Described comparison circuit comprises comparator (U1B) and the second current-limiting resistance (R5), described second current-limiting resistance (R5) one end is connected to the node between voltage-stabiliser tube (U2) and the first current-limiting resistance (R4), and the other end is connected to the negative input end of comparator (U1B);
Described switching circuit comprises NPN type triode (Q1) and the 3rd current-limiting resistance (R7), described 3rd current-limiting resistance (R7) one end connects the output of comparator (U1B), the other end connects the base stage of NPN type triode (Q1), the collector electrode of described NPN type triode (Q1) connects the compensation level end (comp) of the PWM IC of converter, the grounded emitter of described NPN type triode (Q1).
2. converter high accuracy thermal-shutdown circuit according to claim 1, is characterized in that: the node between described second current-limiting resistance (R5) and comparator (U1B) is by the first pull down resistor (R9) ground connection.
3. converter high accuracy thermal-shutdown circuit according to claim 1; it is characterized in that: described comparison circuit also comprises the diode (D1) be arranged between comparator (U1B) and the 3rd current-limiting resistance (R7); the anode of described diode (D1) connects the output of comparator (U1B), its negative electrode serial connection the 3rd current-limiting resistance (R7).
4. converter high accuracy thermal-shutdown circuit according to claim 3; it is characterized in that: described comparison circuit also comprises the second pull down resistor (R6) and the 4th filter capacitor (C3); one end of described second pull down resistor (R6) connects the negative electrode of diode (D1); other end ground connection, described 4th filter capacitor (C3) is in parallel with the second pull down resistor (R6).
5. converter high accuracy thermal-shutdown circuit according to claim 1; it is characterized in that: described switching circuit also comprises the 3rd pull down resistor (R8) and the 3rd filter capacitor (C4); described 3rd filter capacitor (C4) one end is connected with the base stage of NPN type triode (Q1); other end ground connection, described 3rd pull down resistor (R8) is in parallel with the 3rd filter capacitor (C4).
6., according to described converter high accuracy thermal-shutdown circuit arbitrary in Claims 1 to 5, it is characterized in that: described pressurizer (U2) is adjustable three terminal integrated voltage stabilizer.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420826903.0U CN204258272U (en) | 2014-12-23 | 2014-12-23 | A kind of converter high accuracy thermal-shutdown circuit |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201420826903.0U CN204258272U (en) | 2014-12-23 | 2014-12-23 | A kind of converter high accuracy thermal-shutdown circuit |
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| CN204258272U true CN204258272U (en) | 2015-04-08 |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105162087A (en) * | 2015-05-29 | 2015-12-16 | 杭州长川科技股份有限公司 | Power supply protection circuit |
| CN111059038A (en) * | 2018-10-16 | 2020-04-24 | 安徽美芝制冷设备有限公司 | Temperature protection device and method for compressor, compressor system and refrigeration equipment |
| CN111614237A (en) * | 2020-06-17 | 2020-09-01 | 东风汽车有限公司 | Pre-charging circuit, power distribution device and electric automobile |
| CN114336514A (en) * | 2021-12-27 | 2022-04-12 | 浙江正泰汽车科技有限公司 | Electronic preheating relay with protection |
| CN114340094A (en) * | 2022-01-12 | 2022-04-12 | 广东恒润光电有限公司 | LED driving over-temperature protection control method and circuit |
-
2014
- 2014-12-23 CN CN201420826903.0U patent/CN204258272U/en active Active
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105162087A (en) * | 2015-05-29 | 2015-12-16 | 杭州长川科技股份有限公司 | Power supply protection circuit |
| CN111059038A (en) * | 2018-10-16 | 2020-04-24 | 安徽美芝制冷设备有限公司 | Temperature protection device and method for compressor, compressor system and refrigeration equipment |
| CN111614237A (en) * | 2020-06-17 | 2020-09-01 | 东风汽车有限公司 | Pre-charging circuit, power distribution device and electric automobile |
| CN111614237B (en) * | 2020-06-17 | 2022-03-08 | 东风汽车有限公司 | Pre-charging circuit, power distribution device and electric automobile |
| CN114336514A (en) * | 2021-12-27 | 2022-04-12 | 浙江正泰汽车科技有限公司 | Electronic preheating relay with protection |
| CN114340094A (en) * | 2022-01-12 | 2022-04-12 | 广东恒润光电有限公司 | LED driving over-temperature protection control method and circuit |
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