CN205960624U - Switch power -supply overvoltage protecting circuit - Google Patents
Switch power -supply overvoltage protecting circuit Download PDFInfo
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- CN205960624U CN205960624U CN201620894259.XU CN201620894259U CN205960624U CN 205960624 U CN205960624 U CN 205960624U CN 201620894259 U CN201620894259 U CN 201620894259U CN 205960624 U CN205960624 U CN 205960624U
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Abstract
The utility model provides a switch power -supply overvoltage protecting circuit, includes comparison circuit and control circuit, comparison circuit includes comparator and first resistance~fourth resistance, first resistance and second resistor string carried forward, its one end is connected with the power end, other end ground connection, third resistance and fourth resistor string carried forward, its one end is connected with switching power supply's output, other end ground connection, the inverting terminal of comparator holds the point connection that concatenates with third resistance and fourth resistance with the point connection that concatenates of first resistance and second resistance, homophase, and the output is connected with control circuit. The utility model discloses simple structure, the debugging process is simple and convenient to have higher stability and security, be applicable to the overvoltage crowbar who does among any switching power supply.
Description
Technical field
The utility model is related to a kind of improved overvoltage crowbar it is adaptable to when switch power source output voltage is too high,
The switch power over-voltage protection circuit that its load end electrical equipment can be protected, belongs to power technique fields.
Background technology
Developing rapidly with Power Electronic Technique, as source element that must be many in electronic equipment, also enters therewith
Go development and change.Wherein, Switching Power Supply due to its small-sized, light the features such as, gradually by people using entered various electronics,
Electric equipment field, effectively promotes developing rapidly of switch power technology.The operation principle of described Switching Power Supply is to utilize
Modern power electronics technology, controlling switch transistor ON and the time ratio turning off, to maintain one kind of regulated output voltage
Power supply.
At present, most of Switching Power Supply uses based on current type PWM (PulseWidthModulation, pulse width
Degree modulation) chip scheme, be characterized in that frequency is high, efficiency high, there is low cost, structure is simple, stable performance, adjustment of load
The advantages of rate is high.But its defect is then, when power-supply system is in the big abnormal conditions with feedback of load change, system response time
Slowly it is impossible to timely and reliably implement to protect work to fault, easily because Switching Power Supply is when transient high voltage, lead to load
Appearance is burnt, and causes the damage of electrical equipment.Although, market has some utilize thyristor, to set for this kind of problem
The protection circuit of meter, but used by it, component number is more, and circuit structure is more complicated, and the turn-off characteristic of protection circuit is subject to
Silicon controlled parameter affects, and Switching Power Supply easily and cannot thoroughly turn off the phenomena of the failure such as output and misoperation, is difficult by industry
Interior personage is admitted.
Utility model content
The purpose of this utility model is to overcome the deficiencies in the prior art, provides that a kind of structure is simple, debugging is easy and has
There is the switch power over-voltage protection circuit of higher-security and reliability.
Problem described in the utility model solves by the following technical programs：
A kind of switch power over-voltage protection circuit, described protection circuit is connected with the output end of Switching Power Supply；Described protection
Circuit includes comparison circuit and control circuit；Described comparison circuit includes comparator and first resistor～the 4th resistance；Described
After one resistance is concatenated with second resistance, its one end is connected with power end, and the other end is grounded；Described 3rd resistor and the 4th resistance string
After connecing, its one end is connected with the output end of Switching Power Supply, and the other end is grounded；The end of oppisite phase of described comparator and first resistor and the
The concatenation point of two resistance connects, and in-phase end is connected with the concatenation point of 3rd resistor and the 4th resistance, and output end is with control circuit even
Connect.
Above-mentioned switch power over-voltage protection circuit, described control circuit includes the 5th resistance, the first diode and PWN core
Piece；Described first diode is serially connected between the output end of comparator and the control end of PWM chip；One end of described 5th resistance
It is connected with power end, the other end is connected with the tie point of comparator and the first diode.
Above-mentioned switch power over-voltage protection circuit, sets up the second diode, one end of described second diode and comparator
In-phase end connect, the other end is connected with one end of the 5th resistance.
The utility model passes through comparison circuit and control circuit, can effectively the output voltage of Switching Power Supply be carried out
Pressure protection, and its control circuit is to consist of for main element diode, the control electricity more in the past being constituted with controllable silicon
Road is compared, and not only reduces the quantity of components and parts used, makes circuit structure relatively simple additionally it is possible to avoid because being joined by silicon controlled
Number impact, the Switching Power Supply of appearance cannot thoroughly turn off the phenomena of the failure such as output voltage and misoperation.
The utility model structure is simple, and debugging process is easy, and has higher stability and security it is adaptable to make
Overvoltage crowbar in any Switching Power Supply.
Brief description
Fig. 1 is the utility model electrical schematic diagram.
The each list of reference numerals of in figure is：1.PWM chip, R1～R5. first resistor～the 5th resistance, D1. first diode,
D2. the second diode, U. comparator, P. Switching Power Supply.
Specific embodiment
Referring to Fig. 1, the utility model includes comparison circuit and control circuit, and described comparison circuit is used for defeated to Switching Power Supply
The voltage going out end is compared, too high to detect its output voltage.Control circuit is then when overtension is detected, adopts
Take the mode cut off the electricity supply to protect load equipment；Described comparison circuit includes comparator U and first resistor R1～the 4th resistance
R4；After described first resistor R1 is concatenated with second resistance R2, its one end is connected with power end, and the other end is grounded；Described 3rd electricity
After resistance R3 is concatenated with the 4th resistance R4, its one end is connected with the output end of Switching Power Supply P, and the other end is grounded；Described comparator U's
End of oppisite phase is connected with the concatenation point of first resistor R1 and second resistance R2, the string of in-phase end and 3rd resistor R3 and the 4th resistance R4
Contact connects, and output end is connected with the control end of PWM chip 1 after control circuit.
In addition, the control circuit described in the utility model includes biasing circuit, the first diode D1 and PWN chip 1；Institute
State the first diode D1 to be serially connected between the output end of comparator U and the control end of PWM chip 1；Biasing circuit is with comparator U's
Output end connects.Described biasing circuit includes the second diode D2 and the 5th resistance R5；One end of described 5th resistance R5 and electricity
Source connects, and the other end is connected with the tie point of comparator U and the first diode D1；One end of described second diode D2 with than
In-phase end compared with device U connects, and the other end is connected with one end of the 5th resistance R5.
Operation principle of the present utility model is：The output end of Switching Power Supply is exported by resistance R3 and resistance R4 partial pressure
After voltage sampling signal, transmit to the in-phase end of comparator U, thus be connected with comparator end of oppisite phase, by resistance R1 and resistance
The reference voltage that R2 is constituted is compared；When power supply normal work, when output voltage sampled signal is less than setting voltage, i.e. electricity
Pressure comparator U homophase terminal voltage is less than its anti-phase terminal voltage, and comparator output terminal is in low resistance state, the first diode D1 and the 2nd D2
Cut-off；The control end of PWM chip is in low level, PWM chip normal work；If output voltage raises, output voltage is sampled
Signal raises, and when the threshold value set by output voltage reaches reference voltage, output voltage sampled signal is more than setting voltage, that is,
Comparator U homophase terminal voltage is more than its anti-phase terminal voltage, and comparator U output end is in high-impedance state, the 5th resistance R5 passing through and the
The control end of PWM is put high level by one diode D1, makes PWM chip turn off output, Switching Power Supply quits work.Meanwhile, pass through
5th resistance R5, the second diode D2, the 4th resistance R4 in-phase end for comparator U provides inclined higher than end of oppisite phase setting voltage
Put voltage, the output end making comparator U is in that the control end of PWM chip is put high level by high-impedance state always, keeps PWM chip to turn off
State, only just can exit guard mode when Switching Power Supply re-powers start.
Claims (3)
1. a kind of switch power over-voltage protection circuit, described protection circuit is connected with the output end of Switching Power Supply (P)；Its feature exists
In：Described protection circuit includes comparison circuit and control circuit；Described comparison circuit includes comparator (U) and first resistor (R1)
～the four resistance (R4)；After described first resistor (R1) is concatenated with second resistance (R2), its one end is connected with power end, the other end
Ground connection；After described 3rd resistor (R3) is concatenated with the 4th resistance (R4), its one end is connected with the output end of Switching Power Supply (P), separately
One end is grounded；The end of oppisite phase of described comparator (U) is connected with the concatenation point of first resistor (R1) and second resistance (R2), in-phase end
It is connected with the concatenation point of 3rd resistor (R3) and the 4th resistance (R4), output end is connected with control circuit.
2. switch power over-voltage protection circuit according to claim 1 it is characterised in that：Described control circuit includes the 5th
Resistance (R5), the first diode (D1) and PWN chip (1)；Described first diode (D1) is serially connected in the output end of comparator (U)
And the control end of PWM chip (1) between；One end of described 5th resistance (R5) is connected with power end, the other end and comparator (U)
Connect with the tie point of the first diode (D1).
3. switch power over-voltage protection circuit according to claim 2 it is characterised in that：Set up the second diode (D2),
One end of described second diode (D2) is connected with the in-phase end of comparator (U), and one end of the other end and the 5th resistance (R5) is even
Connect.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620894259.XU CN205960624U (en) | 2016-08-18 | 2016-08-18 | Switch power -supply overvoltage protecting circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620894259.XU CN205960624U (en) | 2016-08-18 | 2016-08-18 | Switch power -supply overvoltage protecting circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN205960624U true CN205960624U (en) | 2017-02-15 |
Family
ID=57975645
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201620894259.XU Active CN205960624U (en) | 2016-08-18 | 2016-08-18 | Switch power -supply overvoltage protecting circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN205960624U (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108429239A (en) * | 2018-04-24 | 2018-08-21 | 广州金升阳科技有限公司 | A kind of output overvoltage protection circuit and the power supply comprising the circuit |
| CN112952741A (en) * | 2021-02-25 | 2021-06-11 | 上海空间电源研究所 | Self-locking protection circuit with unlocking switch for overvoltage protection |
| CN117977942A (en) * | 2024-04-02 | 2024-05-03 | 四川升华电源科技有限公司 | Protection circuit and switching power supply |
-
2016
- 2016-08-18 CN CN201620894259.XU patent/CN205960624U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108429239A (en) * | 2018-04-24 | 2018-08-21 | 广州金升阳科技有限公司 | A kind of output overvoltage protection circuit and the power supply comprising the circuit |
| CN112952741A (en) * | 2021-02-25 | 2021-06-11 | 上海空间电源研究所 | Self-locking protection circuit with unlocking switch for overvoltage protection |
| CN117977942A (en) * | 2024-04-02 | 2024-05-03 | 四川升华电源科技有限公司 | Protection circuit and switching power supply |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20200509 Address after: 050035 No. 56, 3 Kunlun street, Shijiazhuang Development Zone, Hebei, China Patentee after: SHIJIAZHUANG GUOYAO ELETRONIC Co.,Ltd. Address before: 050035 No. 56, 3 Kunlun street, Shijiazhuang Development Zone, Hebei, Shijiazhuang Patentee before: HEBEI GUOYAO NEW ENERGY TECHNOLOGY Co.,Ltd. |
|
| TR01 | Transfer of patent right |