CN204030941U - A kind of protective circuit and voltage stabilizing circuit - Google Patents
A kind of protective circuit and voltage stabilizing circuit Download PDFInfo
- Publication number
- CN204030941U CN204030941U CN201420472672.8U CN201420472672U CN204030941U CN 204030941 U CN204030941 U CN 204030941U CN 201420472672 U CN201420472672 U CN 201420472672U CN 204030941 U CN204030941 U CN 204030941U
- Authority
- CN
- China
- Prior art keywords
- coupled
- voltage
- circuit
- output
- 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.)
- Expired - Fee Related
Links
Abstract
The utility model discloses a kind of protective circuit; comprise current foldback circuit and overvoltage crowbar; for providing the service area of a safety for integrated device; and be integrated in voltage-stabilizing device; in addition; the invention also discloses a kind of tandem tap type voltage stabilizing circuit and a kind of paralleling switch type voltage stabilizing circuit, comprise above-mentioned protective circuit.Described tandem tap type voltage stabilizing circuit and paralleling switch type voltage stabilizing circuit both can not burn out because of overcurrent, also can not puncture because of overvoltage.
Description
Technical field
The utility model relates to a kind of protective circuit, especially a kind of safety operation area protective circuit of integrated device.
Background technology
Switching power supply can provide the electronic installation of stable dc power supply for load.Switching power supply can divide tandem tap type stabilized voltage power supply and paralleling switch type stabilized voltage power supply by connected mode, and Type of Switch Stabilivolt Source Circuit part comprises rectification circuit, filter circuit and voltage stabilizing circuit.Its voltage stabilizing circuit comprises testing circuit again, control circuit etc., its principle of stabilized voltage is roughly as follows: testing circuit detects voltage signal at voltage-stabilizing device input, through pwm control circuit process, the action of control switch pipe, the input of the voltage in certain limit to voltage-stabilizing device is exported with this, then the constant voltage that output accuracy is high more after row relax further.But along with the growth of service time, electronic device occurs aging unavoidably, the switching tube that especially operating frequency is the highest.When the element in switching tube or pwm control circuit does not reach required precision, permissible value will be exceeded at the voltage of the formation of voltage-stabilizing device input or the electric current that flows to, this can cause voltage-stabilizing device to damage, to such an extent as to the final spread of voltage exported, cause load end electrical equipment to damage.
Utility model content
For the deficiency that prior art exists, the utility model provides a kind of protective circuit on the one hand, for providing the service area of a safety for integrated device, comprising:
Input, for receiving foreign current;
Output, for outputing current to load;
Constant-current source, is coupled between input and pliotron, for pliotron provides constant electric current;
Current foldback circuit, is coupled between the emitter of pliotron and the output of constant-current source, and when current is excessive, adjustment flows through the electric current of pliotron;
Overvoltage crowbar, is coupled between current foldback circuit and input, and when voltage is excessive, adjustment flows through the electric current of pliotron.
Described protective circuit schematic diagram as shown in Figure 1, is made up of current foldback circuit (1), overvoltage crowbar (2) and mirror current source (3).
Described current foldback circuit (1) is by the first resistance (R1), second resistance (R2), 4th resistance (R4) and a NPN triode (T1) are formed, the collector electrode of a described NPN triode (T1) is coupled to the output of mirror current source (IS), its emitter is coupled to output (Uo), its base stage is coupled between the 4th resistance (R4) and the second resistance (R2), the other end of the 4th described resistance (R4) is coupled to external power triode, the other end of described the second resistance (R2) is coupled to the first resistance (R1), the other end of described the first resistance (R1) is coupled to output (Uo).
Described overvoltage crowbar (2) is made up of the 3rd resistance (R3) and voltage-stabiliser tube (Dz1); the anode of described voltage-stabiliser tube (Dz1) is coupled to the base stage of a NPN triode (T1); its negative electrode is coupled to the 3rd resistance (R3), and the other end of the 3rd described resistance (R3) is coupled to input.
Described mirror current source (3) circuit theory diagrams as shown in Figure 2, be made up of the 5th resistance (R5), the 4th NPN triode (T4) and the 5th NPN triode (T5), one end of the 5th described resistance (R5) is coupled to input (Ui), the other end is coupled to the collector electrode of the 4th NPN triode (T4), the collector electrode of the 4th described NPN triode (T4) is coupled to its base stage, its grounded emitter, the base stage of the 5th described NPN triode (T5) is coupled to the base stage of the 4th NPN triode (T4), its grounded emitter.
The utility model provides a kind of tandem tap type voltage stabilizing circuit, on the other hand for being electronics
Unit is powered, and comprising:
Voltage input end, for receiving external voltage;
Voltage output end, for output voltage to load;
First switching tube, this switching tube comprises first end, is coupled to voltage input end; Second end, is coupled to late-class circuit; Control end, is coupled to late-class circuit;
First pwm circuit, its output is coupled to the control end of the first switching tube, to control it
Action;
First continued flow tube, is coupled between the second end of the first switching tube and voltage input end,
To protect the first pwm circuit element and the first switching tube;
First filter circuit, is coupled to the first continued flow tube and the first pwm circuit, exports with elimination
Ripple in voltage;
First integrated voltage-stabilized pipe, is coupled between the first filter circuit and external loading, with the magnitude of voltage of stable output.
Described tandem tap type voltage stabilizing circuit schematic diagram as shown in Figure 3, by the first switching tube
(T6), first pwm circuit (U1), first continued flow tube (D1), first filter circuit (U3) and the first integrated voltage-stabilized pipe (U5) composition, described the first filter circuit (U3) is made up of the first inductance (L1) and the first electric capacity (C1), the collector electrode of described the first switching tube (T6) is coupled to voltage input end, its emitter is coupled between the negative electrode of the first continued flow tube (D1) and one end of the first inductance (L1), its base stage is coupled to the output of the first pwm circuit (U1), the input of a described PMW circuit (U1) is coupled to the other end of the first inductance (L1), one end of described the first electric capacity (C1) is coupled to the first inductance (L1), the input of the first pwm circuit (U1) and the positive input terminal of the first integrated voltage-stabilized pipe (U5), the anode of described the first continued flow tube (D1), the other end of the first electric capacity (C1) and the negative input end of the first integrated voltage-stabilized pipe (U5) connect voltage input end altogether.
The first described integrated voltage-stabilized pipe comprises Correctional tube and above-mentioned protective circuit, and described voltage-stabiliser tube is coupled to external loading end, and with output voltage, described protective circuit is coupled to Correctional tube, to adjust the electric current flowing through Correctional tube.
The utility model also provides a kind of paralleling switch type voltage stabilizing circuit on the other hand, for being electricity
Subelement is powered, and comprising:
Voltage input end, for receiving external voltage;
Voltage output end, for output voltage to load;
Second switch pipe, this switching tube comprises first end, is coupled to voltage input end; Second end, is coupled to late-class circuit; Control end, is coupled to late-class circuit;
Second pwm circuit, its output is coupled to the control end of second switch pipe, to control it
Action;
Second continued flow tube, is coupled between the second end of second switch pipe and the 2nd PMW circuit,
To protect the second pwm circuit element and second switch pipe;
Second filter circuit, is coupled to voltage input end and voltage output end, exports with elimination
Ripple in voltage;
Second integrated voltage-stabilized pipe, is coupled between the second filter circuit and external loading, with stable
The magnitude of voltage exported.
Described paralleling switch type voltage stabilizing circuit schematic diagram as shown in Figure 4, by second switch pipe
(T7), second pwm circuit (U2), second continued flow tube (D2), second filter circuit (U4) and the second integrated voltage-stabilized pipe (U6) composition, described the second filter circuit (U4) is made up of the second inductance (L2) and the second electric capacity (C2), described the second inductance (L2) is coupled to voltage input end, the collector electrode of described second switch pipe (T7) is coupled to the other end of the second inductance (L2), its emitter is coupled to voltage input end, its base stage is coupled to the output of the second pwm circuit (U2), the input of described the second pwm circuit (U2) is coupled to the negative electrode of the second continued flow tube (D2), the anode of described the second fly-wheel diode (D2) is coupled to the collector electrode of second switch pipe (T7), one end of described the second electric capacity (C2) and the positive input terminal of the second integrated voltage-stabilized pipe (T7) connect voltage input end altogether, the other end of described the second electric capacity (C2) and the negative input end of the second integrated voltage-stabilized pipe (T7) connect voltage input end altogether.
The second described integrated voltage-stabilized pipe comprises Correctional tube and protective circuit, and described Correctional tube is coupled to external loading end, and with output voltage, described protective circuit is coupled to Correctional tube, to adjust the electric current flowing through Correctional tube.
Above-mentioned tandem tap type voltage stabilizing circuit and the integrated voltage-stabilized pipe described in paralleling switch type voltage stabilizing circuit, its circuit theory diagrams as shown in Figure 5, comprising: current foldback circuit (1), overvoltage crowbar (2), mirror current source (3) and Correctional tube (4).
Accompanying drawing explanation
Fig. 1 is protective circuit schematic diagram of the present utility model;
Fig. 2 is mirror current source circuit theory diagrams of the present utility model;
Fig. 3 is tandem tap type voltage stabilizing circuit schematic diagram of the present utility model;
Fig. 4 is paralleling switch type voltage stabilizing circuit schematic diagram of the present utility model;
Fig. 5 is integrated voltage-stabilized pipe circuit theory diagrams of the present utility model.
In figure: 1, current foldback circuit; 2, overvoltage crowbar; 3, mirror current source; 4, Correctional tube; U1, the first pwm circuit; U2 place pwm circuit; U3, the first filter circuit; U4, the second filter circuit; U5, the first integrated voltage-stabilized pipe; U6 second integrated voltage-stabilized pipe; R1, the first resistance; R2, the second resistance; R3, the 3rd resistance; R4, the 4th resistance; R5, the 5th resistance; RL, load resistance; T1, a NPN triode; T2, the 2nd NPN triode; T3, the 3rd NPN triode; T4, the 4th NPN triode; T5, the 5th NPN triode; T6, the first switching tube; T7, second switch pipe; TG, pliotron; DZ1, voltage-stabiliser tube; D1, the first continued flow tube; D2, the second continued flow tube; L1, the first inductance; C1, the first electric capacity; L2, the second inductance; C2, the second electric capacity; Ui, input; Uo, output; UI, voltage input end; UO, voltage output end.
Embodiment
In the circuit shown in Fig. 1, here the integrated device of current foldback circuit (1), overvoltage crowbar (2), mirror current source (3) and pliotron, described current protecting circuit (1) is made up of with a NPN triode (T1) the first resistance (R1), the second resistance (R2), the 4th resistance (R4); Described voltage protection circuit (2) is made up of the 3rd resistance (R3) and voltage-stabiliser tube (Dz1).As noted on the figure, when circuit normally works, voltage-stabiliser tube (Dz1) and a NPN triode (T1) all end output current.Voltage on second resistance (R2) is Ur2=(R2/ (R4+R2)) * Ube3.Between the b-e of the one NPN triode (T1), voltage is Ube1=Ur2+Io*R1, and Ube1<Uon.Io increases, and the voltage on the first resistance (R1) increases, and Ube1 will increase thereupon.
When circuit overloads or output short-circuit, the voltage of the first resistance (R1) increases makes Ube1>Uon, and NPN triode (T1) conducting, shunts pliotron, achieve overcurrent protection.If voltage (i.e. Correctional tube tube voltage drop) exceedes permissible value between Ui and Uo, then D voltage-stabiliser tube (z1) punctures, NPN triode (T1) base current is made suddenly to increase and enter rapidly saturation region, most of electric current of the electric current I that mirror current source provides flows through a NPN triode (T1), thus make pliotron close to cut-off region, namely its power consumption drops to less numerical value.
In the circuit shown in Fig. 2, mirror current source is made up of two identical 4th NPN triodes (T4) of characteristic and the 5th NPN triode (T5), because the tube voltage drop Uceo of the 4th NPN triode (T4) is equal with voltage U beo between its b-e, thus ensure that the 4th NPN triode (T4) is operated in magnifying state, and saturation condition can not be entered, therefore its collector current Ic4=β 4*Ib4, in figure the 4th NPN triode (T4) and the 5th NPN triode (T5) b-e between voltage equal, therefore their base current Ib4=Ib5=Ib, and due to currentamplificationfactorβ 4=β 5=β, therefore collector current Ic4=Ic5=Ic=β * Ib.Visible, due to this special connection of circuit, make Ic5 and Ic4 be mirror, the electric current in the 5th resistance (R5) is reference current, and its expression formula is Ir=(Vcc-Ube)/R5=Ic+2*Ib=Ic+2*Ic/ β.So collector current Ic=(β/(β+2)) * Ir.When β much larger than 2 time, output current Ic5 ≈ Ir=(Vcc-Ube)/R5.When numerical value one timing of Vcc and the 5th resistance (R5), Ic5 also just determines thereupon, and stablely exports.
In the electronic circuit as shown in figure 3, first pwm circuit (U1) gathers the voltage at the first electric capacity (C1) place, through pwm circuit inter-process (the reference voltage circuit stable output voltage in pwm circuit, the difference of sampled voltage and reference voltage, after amplifier amplifies, the threshold voltage exported is compared with the output voltage of triangle wave generating circuit), obtain control signal, control the operating state of the first switching tube (T6).During the first switching tube (T6) conducting, electric current charges to the first electric capacity (C1) through the first switching tube (T6) and the first inductance (L1), and the first integrated voltage-stabilized pipe (U5) receives the voltage at the first electric capacity (C1) two ends, exports constant voltage to load.If the brownout at the first electric capacity (C1) place, the first pwm circuit (U1) controls the first switching tube (T6) conducting, and the first electric capacity (C1) charges; If the overtension at the first electric capacity (C1) place, the first pwm circuit (U1) controls the first switching tube (T6) and turns off, and the first electric capacity (C1) discharges.The voltage stabilization of such maintenance first integrated voltage-stabilized pipe (U5) input is in allowed band.
In the circuit shown in Fig. 4, second pwm circuit (U2) gathers the voltage at the second electric capacity (C2) place, through pwm circuit inter-process (the reference voltage circuit stable output voltage in pwm circuit, the difference of sampled voltage and reference voltage, after amplifier amplifies, the threshold voltage exported is compared with the output voltage of triangle wave generating circuit), obtain control signal, control the operating state of second switch pipe (T7).During second switch pipe (T7) conducting, electric current flows through second switch pipe (T7) through inductance and does not charge to the second electric capacity (C2); When second switch pipe (T7) turns off, because the afterflow effect of the second inductance (L2), electric current charges to the second electric capacity (C2) through the second continued flow tube (D2).Second integrated voltage-stabilized pipe (U6) receives the voltage at the second electric capacity (C2) two ends, exports constant voltage to load.If the brownout at the second electric capacity (C2) place, the second pwm circuit (U2) controls second switch pipe (T7) and turns off, and the second electric capacity (C2) charges; If the overtension at the second electric capacity (C2) place, the second pwm circuit (U2) controls second switch pipe (T7) and turns off, and the second electric capacity (C2) discharges.The voltage stabilization of such maintenance second integrated voltage-stabilized pipe (U6) input is in allowed band.
In the circuit shown in Fig. 5, current foldback circuit (1) here, overvoltage crowbar (2), mirror current source (3) and Correctional tube (4) are integrated into a voltage-stabilizing device, for above-mentioned two kinds of switching mode voltage stabilizing circuits.Described Correctional tube (4) is made up of the 2nd NPN triode (T2) and the 3rd NPN triode (T3), and the emitter of the 2nd NPN triode (T2) is coupled to the base stage of the 3rd NPN triode (T3), and two pipes form multiple tube, and amplification coefficient doubles.
Described current protecting circuit (1) is made up of with a NPN triode (T1) the first resistance (R1), the second resistance (R2), the 4th resistance (R4); Described voltage protection circuit (2) is made up of the 3rd resistance (R3) and voltage-stabiliser tube (Dz1).As noted on the figure, when circuit normally works, voltage-stabiliser tube (Dz1) and a NPN triode (T1) all end output current.Voltage on second resistance (R2) is Ur2=(R2/ (R4+R2)) * Ube3.Between the b-e of the one NPN triode (T1), voltage is Ube1=Ur2+Io*R1, and Ube1<Uon.Io increases, and the voltage on the first resistance (R1) increases, and Ube1 will increase thereupon.
When circuit overloads or output short-circuit, the voltage of the first resistance (R1) increases makes Ube1>Uon, and NPN triode (T1) conducting, to the base bleeder current of Correctional tube (4), achieves overcurrent protection.If voltage (pole Correctional tube tube voltage drop) exceedes permissible value between Ui and Uo, then D voltage-stabiliser tube (z1) punctures, NPN triode (T1) base current is made suddenly to increase and enter rapidly saturation region, most of electric current of the electric current I that mirror current source provides flows through a NPN triode (T1), the electric current assigning to the 2nd NPN triode (T2) is made to be reduced to minimum On current, thus make the 3rd NPN triode (T3) close to cut-off region, because Q=I^2Rt, when electric current reduces at double, its power consumption also drops to less numerical value.
In sum; above-mentioned protective circuit can make Correctional tube neither burn out because of overcurrent, does not also puncture because of overvoltage, and its integrated voltage-stabilizing device is applied to tandem tap type voltage stabilizing circuit and paralleling switch type voltage stabilizing circuit; by overcurrent protection and overvoltage protection, to guarantee the voltage of stable output.
The above is only preferred implementation of the present utility model, protection range of the present utility model be not only confined to above-described embodiment, and all technical schemes belonged under the utility model thinking all belong to protection range of the present utility model.It should be pointed out that for those skilled in the art, do not departing from the some improvements and modifications under the utility model principle prerequisite, these improvements and modifications also should be considered as protection range of the present utility model.
Claims (8)
1. a protective circuit, for providing the service area of a safety for integrated device, its
Be characterised in that: comprising:
Input, for receiving foreign current;
Output, for outputing current to load;
Constant-current source, is coupled between input and pliotron, for pliotron provides constant electric current;
Current foldback circuit, is coupled between the emitter of pliotron and the output of constant-current source, and when current is excessive, adjustment flows through the electric current of pliotron;
Overvoltage crowbar, is coupled between current foldback circuit and input, and when voltage is excessive, adjustment flows through the electric current of pliotron.
2. protective circuit according to claim 1, is characterized in that: described overcurrent is protected
Protection circuit comprises:
One NPN triode, its collector electrode is coupled to the output of constant-current source, and emitter is coupled to output;
4th resistance, is coupled to the base stage of a NPN triode;
Second resistance, is coupled to the 4th resistance;
First resistance, one end is coupled to the second resistance, and the other end is coupled to output.
3. protective circuit according to claim 1, is characterized in that: described overvoltage is protected
Protection circuit comprises:
3rd resistance, one end is coupled to input;
Voltage-stabiliser tube, one end is coupled to the 3rd resistance, and the other end is coupled to the base stage of a NPN triode.
4. protective circuit according to claim 1, is characterized in that: described constant-current source
Be mirror current source, comprise:
5th resistance, is coupled to input;
4th NPN triode, its collector electrode is coupled to the 5th resistance, and is coupled to base stage, grounded emitter;
5th NPN triode, its base stage is coupled to the base stage of the 4th NPN triode, grounded emitter.
5. a tandem tap type voltage stabilizing circuit, for powering for electronic unit, its feature exists
In: comprising:
Voltage input end, for receiving external voltage;
Voltage output end, for output voltage to load;
First switching tube, this switching tube comprises first end, is coupled to voltage input end; Second end, is coupled to late-class circuit; Control end, is coupled to late-class circuit;
First pwm circuit, its output is coupled to the control end of the first switching tube, to control it
Action;
First continued flow tube, is coupled between the second end of the first switching tube and voltage input end,
To protect the first pwm circuit element and the first switching tube;
First filter circuit, is coupled to the first continued flow tube and the first pwm circuit, exports with elimination
Ripple in voltage;
First integrated voltage-stabilized pipe, is coupled between the first filter circuit and external loading, with the magnitude of voltage of stable output.
6. tandem tap type voltage stabilizing circuit according to claim 5, is characterized in that: institute
The the first integrated voltage-stabilized pipe stated comprises:
Correctional tube, is coupled to external loading end, with output voltage;
Protective circuit as described in Claims 1-4 any one, is coupled to Correctional tube, to adjust the electric current flowing through Correctional tube.
7. a paralleling switch type voltage stabilizing circuit, for powering for electronic unit, its feature exists
In: comprising:
Voltage input end, for receiving external voltage;
Voltage output end, for output voltage to load;
Second switch pipe, this switching tube comprises first end, is coupled to voltage input end; Second end, is coupled to late-class circuit; Control end, is coupled to late-class circuit;
Second pwm circuit, its output is coupled to the control end of second switch pipe, to control it
Action;
Second continued flow tube, is coupled between the second end of second switch pipe and the 2nd PMW circuit,
To protect the second pwm circuit element and second switch pipe;
Second filter circuit, is coupled to voltage input end and voltage output end, exports with elimination
Ripple in voltage;
Second integrated voltage-stabilized pipe, is coupled between the second filter circuit and external loading, with stable
The magnitude of voltage exported.
8. paralleling switch type voltage stabilizing circuit according to claim 7, is characterized in that: institute
The the second integrated voltage-stabilized pipe stated comprises:
Correctional tube, is coupled to external loading end, with output voltage;
Protective circuit as described in Claims 1-4 any one, is coupled to Correctional tube, to adjust the electric current flowing through Correctional tube.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420472672.8U CN204030941U (en) | 2014-08-21 | 2014-08-21 | A kind of protective circuit and voltage stabilizing circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420472672.8U CN204030941U (en) | 2014-08-21 | 2014-08-21 | A kind of protective circuit and voltage stabilizing circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN204030941U true CN204030941U (en) | 2014-12-17 |
Family
ID=52070766
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201420472672.8U Expired - Fee Related CN204030941U (en) | 2014-08-21 | 2014-08-21 | A kind of protective circuit and voltage stabilizing circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN204030941U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106602857A (en) * | 2016-12-26 | 2017-04-26 | 科世达（上海）管理有限公司 | Self-adaptive dummy load circuit and switching power supply |
| CN110061616A (en) * | 2019-05-15 | 2019-07-26 | 上海艾为电子技术股份有限公司 | Power-switching circuit with short-circuit protection |
-
2014
- 2014-08-21 CN CN201420472672.8U patent/CN204030941U/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106602857A (en) * | 2016-12-26 | 2017-04-26 | 科世达（上海）管理有限公司 | Self-adaptive dummy load circuit and switching power supply |
| CN110061616A (en) * | 2019-05-15 | 2019-07-26 | 上海艾为电子技术股份有限公司 | Power-switching circuit with short-circuit protection |
| CN110061616B (en) * | 2019-05-15 | 2021-06-18 | 上海艾为电子技术股份有限公司 | Power supply conversion circuit with short-circuit protection |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN205453114U (en) | Power supply surge inhibitor with prevent joining conversely function | |
| CN103545803B (en) | Device power supply (DPS) interface circuit protection device | |
| WO2018006769A1 (en) | Hysteresis power supply circuit | |
| CN107528298B (en) | Protection circuit of electronic load and electronic load | |
| CN203787956U (en) | Surge voltage suppression circuit | |
| US9018931B2 (en) | Control system for providing circuit protection to a power supply | |
| CN207612045U (en) | A kind of protection chip | |
| CN111224374B (en) | Protective circuit | |
| US10033347B2 (en) | DC/DC electrical configuration for operating over a large span of input voltages | |
| CN204030941U (en) | A kind of protective circuit and voltage stabilizing circuit | |
| CN104218558A (en) | Surge-prevention high-voltage protection circuit | |
| CN107979281B (en) | Input voltage division module and overvoltage protection switch | |
| CN209132655U (en) | A kind of voltage regulator circuit | |
| CN111030071A (en) | Surge suppression power supply protection circuit | |
| CN204794665U (en) | Two export power supply steady voltage protection circuits | |
| CN204992542U (en) | Dead type overvoltage crowbar of lock | |
| CN113162011A (en) | Overvoltage protection circuit and power supply circuit | |
| CN217115611U (en) | Overvoltage protection circuit and electrical equipment | |
| CN209389690U (en) | One kind being applied to intercom internal electric source overvoltage crowbar | |
| CN219227421U (en) | Starting circuit of auxiliary power supply applied to high-frequency switching power supply | |
| CN112242787A (en) | Simple impact current suppression circuit | |
| CN219394443U (en) | Charging protection circuit and electric equipment | |
| CN217469755U (en) | Low-voltage power supply protection circuit | |
| CN216625579U (en) | PWM control chip power supply circuit and switching power supply | |
| CN216699826U (en) | Voltage stabilizing device protection circuit |
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: 20141217 Termination date: 20190821 |