CN204258273U - A kind of converter high accuracy protection circuit against input over-voltage - Google Patents
A kind of converter high accuracy protection circuit against input over-voltage Download PDFInfo
- Publication number
- CN204258273U CN204258273U CN201420826937.XU CN201420826937U CN204258273U CN 204258273 U CN204258273 U CN 204258273U CN 201420826937 U CN201420826937 U CN 201420826937U CN 204258273 U CN204258273 U CN 204258273U
- Authority
- CN
- China
- Prior art keywords
- voltage
- current
- resistance
- filter capacitor
- limiting resistance
- Prior art date
- 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.)
- Active
Links
Abstract
The utility model is specifically related to a kind of high accuracy protection circuit against input over-voltage for interchanger, mainly comprises sample circuit, voltage stabilizing circuit, comparison circuit, switching circuit; Described sample circuit comprises resistance R1, the first divider resistance R2, the second divider resistance R3 and the first filter capacitor C1; Described voltage stabilizing circuit 2 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 overvoltage protection 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 protection circuit against input over-voltage for interchanger.
Background technology
Converter is the device that information information source sent is undertaken by certain object converting, and usually adopts PWMIC to control whole power supply, ensures the value of stable output.And converter generally needs protection circuit against input over-voltage to ensure the stable of circuit and safety.Present overvoltage crowbar 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 protection circuit against input over-voltage, inputs overvoltage protection reliably for converter provides.
For achieving the above object, the utility model can be achieved by the following technical programs:
A kind of converter high accuracy protection circuit against input over-voltage, 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 resistance R1, the first divider resistance R2, the second divider resistance R3 and the first filter capacitor C1, one end of described resistance R1 connects voltage input end Vin+, the other end is by the first divider resistance R2 ground connection, described second divider resistance R3 and the first filter capacitor C1 is in parallel with the first divider resistance R2 respectively, and the node between described resistance R1 and the first divider resistance R2 is connected to the positive input terminal of comparison circuit 3;
Described voltage stabilizing circuit 2 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; comparator U1B is utilized to compare reference voltage and sampled voltage; when sampled voltage is greater than set point; 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 overvoltage protection.
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 overvoltage protection 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 protection circuit against input over-voltage described in the utility model, mainly comprises sample circuit, voltage stabilizing circuit, comparison circuit and switching circuit.
Sample circuit, for exporting accurate sampling voltage, comprises resistance R1, the first divider resistance R2, the second divider resistance R3 and the first filter capacitor C1.Resistance R1, the first divider resistance R2 and the second divider resistance R3 are voltage sampling resistor, one end of resistance R1 connects voltage input end Vin+, the other end is by the first divider resistance R2 ground connection, second divider resistance R3 and the first filter capacitor C1 is in parallel with the first divider resistance R2 respectively, first filter capacitor C1 stablizes sampling voltage, prevent sampling voltage to fluctuate, make sampling voltage value more accurate.Node between resistance R1 and the first divider resistance R2 is connected to the positive input terminal of the comparator U1B of comparison circuit 3.The setting of resistance R1, the first divider resistance R2 and the second divider resistance R3 comes from overvoltage protection value, Vin+=2.49* (1+R1/ (R2*R3)/(R2+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; when sampled voltage is greater than set point; 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 overvoltage protection.
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 protection circuit against input over-voltage, 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 resistance (R1), the first divider resistance (R2), the second divider resistance (R3) and the first filter capacitor (C1), one end of described resistance (R1) connects voltage input end (Vin+), the other end is by the first divider resistance (R2) ground connection, described second divider resistance (R3) and the first filter capacitor (C1) are in parallel with the first divider resistance (R2) respectively, and the node between described resistance (R1) and the first divider resistance (R2) is connected to the positive input terminal of comparison circuit;
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 protection circuit against input over-voltage 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 protection circuit against input over-voltage 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 protection circuit against input over-voltage 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 protection circuit against input over-voltage 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 protection circuit against input over-voltage arbitrary in Claims 1 to 5, it is characterized in that: described pressurizer (U2) is adjustable three terminal integrated voltage stabilizer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420826937.XU CN204258273U (en) | 2014-12-23 | 2014-12-23 | A kind of converter high accuracy protection circuit against input over-voltage |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420826937.XU CN204258273U (en) | 2014-12-23 | 2014-12-23 | A kind of converter high accuracy protection circuit against input over-voltage |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN204258273U true CN204258273U (en) | 2015-04-08 |
Family
ID=52962541
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201420826937.XU Active CN204258273U (en) | 2014-12-23 | 2014-12-23 | A kind of converter high accuracy protection circuit against input over-voltage |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN204258273U (en) |
-
2014
- 2014-12-23 CN CN201420826937.XU patent/CN204258273U/en active Active
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN204258272U (en) | A kind of converter high accuracy thermal-shutdown circuit | |
| CN103280765A (en) | Overvoltage protection circuit | |
| CN102332704B (en) | Switching power supply input undervoltage or overvoltage protection circuit | |
| CN102081418B (en) | Linear constant voltage control circuit | |
| CN204046130U (en) | A kind of overvoltage type current foldback circuit | |
| CN214100826U (en) | Secondary overcurrent protection circuit of switching power supply | |
| CN104538936A (en) | Input overvoltage protection circuit of switching power supply | |
| CN204258261U (en) | A kind of converter high accuracy input undervoltage protection circuit | |
| CN103941794A (en) | Series connection type transistor voltage stabilizing circuit with differential amplification function | |
| CN203673378U (en) | Low-dropout direct-current stabilized power supply circuit | |
| CN202424498U (en) | Protection circuit applicable to PWM (pulse-width modulation) power control circuit | |
| CN204258273U (en) | A kind of converter high accuracy protection circuit against input over-voltage | |
| CN104569547B (en) | Automotive system cell voltage low voltage monitoring circuit | |
| CN103346546A (en) | Lightning protection circuit used for remote measurement terminal | |
| CN203289075U (en) | Overvoltage protection circuit | |
| CN202797873U (en) | Light-emitting diode (LED) short-circuit protection circuit | |
| CN209072053U (en) | A kind of self- recoverage type current foldback circuit | |
| CN204992542U (en) | Dead type overvoltage crowbar of lock | |
| CN210037954U (en) | Power supply voltage overvoltage and undervoltage protection indicating circuit | |
| CN103091543A (en) | Current detection circuit, constant current circuit and battery charging and discharging protective system | |
| CN203720260U (en) | Electric energy meter having power protection circuit | |
| CN102916587B (en) | Digital adjustable bipolar high-voltage power supply | |
| CN109149523B (en) | Self-recovery type overcurrent protection circuit | |
| CN203312785U (en) | Lightning protection circuit of telemetry terminal machine | |
| CN203365537U (en) | Autoreclose circuit breaker leakage current detection circuit |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant |