CN202840470U - Under-voltage protection circuit - Google Patents
Under-voltage protection circuit Download PDFInfo
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- CN202840470U CN202840470U CN201220471417.2U CN201220471417U CN202840470U CN 202840470 U CN202840470 U CN 202840470U CN 201220471417 U CN201220471417 U CN 201220471417U CN 202840470 U CN202840470 U CN 202840470U
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Abstract
The utility model discloses an under-voltage protection circuit. The under-voltage protection circuit comprises an input voltage detection circuit, an under-voltage comparison protection output circuit connected with the input voltage detection circuit, and an under-voltage protection return difference circuit that is connected with the under-voltage comparison protection output circuit and is connected to the input voltage detection circuit. The under-voltage protection circuit is characterized by further comprising an under-voltage protection time-delay circuit that is connected with the under-voltage comparison protection output circuit and is connected to the input voltage detection circuit, and a shielding under-voltage protection time-delay circuit that is connected with the under-voltage protection time-delay circuit. According to the under-voltage protection circuit, requirements about input voltages for a power source are minimized, thereby minimizing usage of input capacitors and lowering costs of the power source. The input capacitors are minimized, thereby saving spaces for other power devices and substantially improving power density of the power source. The requirements about input voltages are minimized and requirements for a pre-stage power source are reduced, thus reducing costs of a whole system.
Description
Technical field
The utility model relates to a kind of under-voltage protecting circuit; more particularly, relate to a kind of comprise input voltage detection circuit, be connected with this input voltage detection circuit under-voltage relatively protect output circuit with this under-voltage under-voltage protecting circuit of relatively protecting output circuit to be connected and being connected to the under-voltage protection return difference circuit of input voltage detection circuit.
Background technology
The tradition under-voltage protecting circuit is by input voltage detection circuit, under-voltage output circuit, the under-voltage protection return difference the electric circuit constitute relatively protected.Structured flowchart as shown in Figure 1, preferred embodiment is shown in Figure 2.
There is following technological deficiency in it based on the existing under-voltage protecting circuit of said structure; necessarily require input voltage very stable; when input voltage is beated between under-voltage point and recovery point (voltage of this variation is greater than under-voltage return difference); power supply will be in the switching on and shutting down alternating state, and output voltage waveforms is with continuous saltus step.For fear of this problem, often need the larger electric capacity of input, guarantee that input voltage is level and smooth, large saltus step does not appear.Especially the exigent power supply of low temperature must use a plurality of input capacitance parallel connections with the ESR of less input capacitance, plays again machine after causing shutdown because ESR is excessive when preventing from shutting down.
Summary of the invention
In order to overcome power supply to the strong dependency of input voltage, the utility model provides a kind of under-voltage protecting circuit, and this under-voltage protecting circuit has reduced the use of input capacitance greatly, has saved cost, has improved the power density of power supply.
The technical scheme that its technical problem that solves the utility model adopts is as described below: a kind of under-voltage protecting circuit; comprise input voltage detection circuit, be connected with this input voltage detection circuit under-voltage relatively protect output circuit with this under-voltage under-voltage protection return difference circuit of relatively protecting output circuit to be connected and being connected to input voltage detection circuit; it is characterized in that, also comprise and the under-voltage under-voltage protection delay circuit of relatively protecting output circuit to be connected and being connected to input voltage detection circuit.
According to the utility model of said structure, further, it is characterized in that: described under-voltage protection delay circuit connects a shielding under-voltage protection delay circuit.
The operation principle of the utility model front three parts is identical with traditional under-voltage protecting circuit; the input power testing circuit draws the signal of a reflection input voltage; draw guard signal after this signal and the reference signal; if the under-voltage protection signal is effective; under-voltage protection return difference circuit operation, the assurance under-voltage protection is reliably overturn and certain under-voltage return difference is provided.After the under-voltage protection action, under-voltage delay circuit selectivity action: when being in when meeting operation condition, under-voltage protection deferred action, power supply enters long-time off state, turn-off time length is determined that by the delay circuit delay time after delay time finished, under-voltage protection recovered normal condition, meet the condition of work start, do not meet the compressor start up condition power supply and be in off state; When under-voltage protecting circuit action and under-voltage delay circuit when not meeting operation condition, the action of shielding under-voltage protection delay circuit, under-voltage protection at this moment is the same with traditional under-voltage protecting circuit operation principle.
According to the utility model of said structure, its beneficial effect is that the utility model is so that power supply requires reduction to input voltage, thereby the use of reduction input capacitance reduces the power supply cost; Reduce input capacitance, saved the space for other power devices, greatly improved power density; Input voltage requires to reduce, and has reduced the requirement of front level power supply, thereby reduces the cost of whole system; The energy that feeds back on the input capacitance after the power supply shutdown amplifies, and has greatly reduced design difficulty.
Description of drawings
Below in conjunction with accompanying drawing and embodiment the utility model is described further.
Fig. 1 is existing traditional under-voltage protecting circuit structured flowchart;
Fig. 2 is existing traditional under-voltage protecting circuit preferred embodiment schematic diagram;
Fig. 3 is the utility model circuit structure block diagram;
Fig. 4 is the utility model embodiment one circuit theory diagrams.
Embodiment
As shown in Figure 3; a kind of under-voltage protecting circuit; comprise input voltage detection circuit, be connected with this input voltage detection circuit under-voltage relatively protect output circuit with this under-voltage under-voltage protection return difference circuit of relatively protecting output circuit to be connected and being connected to input voltage detection circuit, also comprise with under-voltage and relatively protect output circuit to be connected and be connected to the under-voltage protection delay circuit of input voltage detection circuit and the shielding under-voltage protection delay circuit that is connected with the under-voltage protection delay circuit.
The utility model has utilized the characteristics of traditional circuit, has solved simultaneously the problem that traditional circuit exists and does not introduce new problem.Such as when the input voltage power-off shutdown, input voltage occurs first coming back to recovery point when above with turn-offing below the under-voltage protection then because of a variety of causes input voltage, if use traditional under-voltage protecting circuit, the rear output that will occur shutting down restarts and turn-offs phenomenon, occurs repeatedly restarting shutoff when serious; Use the utility model, as long as it is long just more passable than the time that input capacitance discharges into below the under-voltage recovery point that delay time is set, the input capacitance amount of capacity is just unimportant like this.
The utility model adopts shielding under-voltage protection delay circuit, masks the certain situation when not good behind the delay circuit.When output does not have time-delay good on the contrary, can by detecting the output shielded signal, avoid unnecessary problem to occur.
Come below by the course of work of embodiment one that the utility model is described in further detail:
As shown in Figure 4, after the line under-voltage state occurs, under-voltage circuit operation, high level appears in 4 pin of U1, if this moment, step signal, namely Q2 did not appear in PVCC, R2, C2 is action not, and this moment, the 4 pin high voltage out of U1 passed through R3, R1, Q1, C1 drags down 3 pin of U1, the power supply long-term performance is the undervoltage turnoff state, when C1 be charged to the upper voltage of R1 less than Q1 Vgth the time, time-delay short-circuit failure, the normal detected state of power up.PVCC when also having step voltage high level appears and in 4 pin of U1, and the Q2 conducting is so that R3, R1, not action of Q1, the network that C1 forms, not action of delay circuit, identical among the circuit of this moment and traditional under-voltage protecting circuit Fig. 1.
When power supply plays machine; input voltage is from the set point that is raised to above freezing; under-voltage protection output high level phenomenon appears in this process unavoidably; if delay circuit action; output delay time can only greater than the under-voltage protection delay time, when having required the machine delay time smaller, be difficult to meet the demands so; avoided the generation of this problem by screened circuit this moment.
Claims (2)
1. under-voltage protecting circuit; comprise input voltage detection circuit, be connected with this input voltage detection circuit under-voltage relatively protect output circuit with this under-voltage under-voltage protection return difference circuit of relatively protecting output circuit to be connected and being connected to input voltage detection circuit, it is characterized in that: also comprise and the under-voltage under-voltage protection delay circuit of relatively protecting output circuit to be connected and being connected to input voltage detection circuit.
2. a kind of under-voltage protecting circuit according to claim 1 is characterized in that: described under-voltage protection delay circuit connection one shielding under-voltage protection delay circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201220471417.2U CN202840470U (en) | 2012-09-17 | 2012-09-17 | Under-voltage protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201220471417.2U CN202840470U (en) | 2012-09-17 | 2012-09-17 | Under-voltage protection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN202840470U true CN202840470U (en) | 2013-03-27 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201220471417.2U Expired - Lifetime CN202840470U (en) | 2012-09-17 | 2012-09-17 | Under-voltage protection circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN202840470U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2016061959A1 (en) * | 2014-10-24 | 2016-04-28 | 中兴通讯股份有限公司 | Undervoltage protection circuit processing method and apparatus, and undervoltage protection system |
-
2012
- 2012-09-17 CN CN201220471417.2U patent/CN202840470U/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2016061959A1 (en) * | 2014-10-24 | 2016-04-28 | 中兴通讯股份有限公司 | Undervoltage protection circuit processing method and apparatus, and undervoltage protection system |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CP01 | Change in the name or title of a patent holder |
Address after: 518000 Shenzhen City, Shenzhen, Guangdong, Nanshan District Taoyuan street, No. 1268, honghualing industrial North District, 1, 2 4 floors, West, 5, 6. Patentee after: SHENZHEN VAPEL POWER SUPPLY TECHNOLOGY CO.,LTD. Address before: 518000 Shenzhen City, Shenzhen, Guangdong, Nanshan District Taoyuan street, No. 1268, honghualing industrial North District, 1, 2 4 floors, West, 5, 6. Patentee before: SHENZHEN VAPEL POWER SUPPLY TECH. Co.,Ltd. |
|
| CP01 | Change in the name or title of a patent holder | ||
| CP02 | Change in the address of a patent holder |
Address after: 518116 Shenzhen, Longgang, Guangdong Longgang District, Baolong Industrial Zone, Longgang Road, three road 4, A Building 1, 2 floor B building 3, 4 floor C building 3, 4 Building D Patentee after: SHENZHEN VAPEL POWER SUPPLY TECHNOLOGY CO.,LTD. Address before: 518000 Guangdong Shenzhen Nanshan District Taoyuan street, No. 1268, No. 1, 2, 4, West, 5, 6 floor. Patentee before: SHENZHEN VAPEL POWER SUPPLY TECHNOLOGY CO.,LTD. |
|
| CP02 | Change in the address of a patent holder | ||
| CX01 | Expiry of patent term |
Granted publication date: 20130327 |
|
| CX01 | Expiry of patent term |