CN211856718U - Overcurrent detection circuit - Google Patents
Overcurrent detection circuit Download PDFInfo
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- CN211856718U CN211856718U CN201921981296.4U CN201921981296U CN211856718U CN 211856718 U CN211856718 U CN 211856718U CN 201921981296 U CN201921981296 U CN 201921981296U CN 211856718 U CN211856718 U CN 211856718U
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- current
- current detection
- overcurrent
- detection circuit
- limiting resistor
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Abstract
The utility model discloses an overcurrent detection circuit, which comprises a current detection resistor R1, a current detection triode Q1, a current limiting resistor R2 and a current limiting resistor R3; one end of the current detection resistor R1 is connected with the emitting electrode of the current detection triode Q1 and serves as the input end of the overcurrent detection circuit, the other end of the current detection resistor R1 is connected with one end of the current limiting resistor R2 and serves as the output end of the overcurrent detection circuit, the other end of the current limiting resistor R2 is connected with the base electrode of the current detection triode Q1, the collector electrode of the current detection triode Q1 is connected with one end of the current limiting resistor R3, and the other end of the current limiting resistor R3 serves as the control end of the overcurrent detection circuit. The utility model discloses the circuit is simple and low cost, and when the electric current reached and predetermine the electric current upper limit, provide an overcurrent low-voltage signal and carry out power supply overcurrent protection for feedback circuit or control circuit, the power is closed, waits that the overcurrent removes the back unusually, and the power can restart.
Description
Technical Field
The utility model relates to a power protection field, in particular to overcurrent detection circuit.
Background
The main output part of the prior multi-path output power supply is provided with an overcurrent detection protection circuit, but for the part with low current output, the overcurrent detection protection circuit is not added usually; because the addition of the over-current detection protection circuit requires the addition of a complex comparator or an over-current detection integrated module, the circuit is relatively complex and high in cost. In some small current circuits, overcurrent protection is required for safety requirements, for example, in the current-12V part of a computer power supply, no overcurrent protection circuit is applied to the current of about 0.3A, and the power supply can be damaged if an overcurrent condition occurs.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to provide an overcurrent detection circuit, to the defect deep research on the current power supply ware, neither increase cost also can reach overcurrent protection's function.
In order to realize the purpose, the utility model discloses a technical scheme as follows:
an overcurrent detection circuit comprises a current detection resistor R1, a current detection triode Q1, a current limiting resistor R2 and a current limiting resistor R3; one end of the current detection resistor R1 is connected with the emitting electrode of the current detection triode Q1 and serves as the input end of the overcurrent detection circuit, the other end of the current detection resistor R1 is connected with one end of the current limiting resistor R2 and serves as the output end of the overcurrent detection circuit, the other end of the current limiting resistor R2 is connected with the base electrode of the current detection triode Q1, the collector electrode of the current detection triode Q1 is connected with one end of the current limiting resistor R3, and the other end of the current limiting resistor R3 serves as the control end of the overcurrent detection circuit.
Preferably, the input end of the over-current detection circuit is connected with the output end of the power supply to be protected.
Preferably, the power supply to be protected includes a transformer T, a capacitor C1 and a diode D1, one end of a secondary winding of the transformer T is connected to one end of the capacitor C1 and serves as an output end of the power supply to be protected, the other end of the capacitor C1 is connected to an anode of the diode D1 and is grounded, and a cathode of the diode D1 is connected to the other end of the secondary winding of the transformer T.
Preferably, the control end of the over-current detection circuit is connected with the control circuit.
Preferably, the current detection transistor Q1 is an NPN transistor.
After the structure of the oil-water separator is adopted, the utility model discloses the circuit is simple and low cost, and when the electric current was too big (reached and predetermine the electric current upper limit), the current detection resistance detected 0.7V voltage, reached the threshold voltage of triode, and trigger current detects the triode and will switch on, provides an overcurrent low-voltage signal and carries out power supply overcurrent protection for feedback circuit or control circuit, and the power is closed, waits that the overcurrent removes the back unusually, and the power can be started again.
The present invention will be further described with reference to the accompanying drawings and the following detailed description.
Drawings
Fig. 1 is a schematic block circuit diagram of the present invention;
fig. 2 is a schematic block diagram of an embodiment of the present invention.
Detailed Description
As shown in fig. 1, the present invention discloses an over-current detection circuit, which includes a current detection resistor R1, a current detection triode Q1, a current limiting resistor R2 and a current limiting resistor R3; one end of the current detection resistor R1 is connected with the emitting electrode of the current detection triode Q1 and serves as the input end of the overcurrent detection circuit, the other end of the current detection resistor R1 is connected with one end of the current limiting resistor R2 and serves as the output end of the overcurrent detection circuit, the other end of the current limiting resistor R2 is connected with the base electrode of the current detection triode Q1, the collector electrode of the current detection triode Q1 is connected with one end of the current limiting resistor R3, and the other end of the current limiting resistor R3 serves as the control end of the overcurrent detection circuit.
As shown in fig. 2, the input terminal of the over-current detection circuit is connected to the output terminal of the power supply to be protected; the power supply to be protected comprises a transformer T, a capacitor C1 and a diode D1, one end of a secondary winding of the transformer T is connected with one end of the capacitor C1 and serves as an output end of the power supply to be protected, the other end of the capacitor C1 is connected with an anode of the diode D1 and is grounded, and a cathode of the diode D1 is connected with the other end of the secondary winding of the transformer T.
The control end of the over-current detection circuit is connected with the control circuit or the feedback circuit to execute power over-current protection, for example, the power supply is turned off, and the power supply can be restarted after the over-current abnormity is relieved.
Preferably, the current detection transistor Q1 is an NPN transistor.
When the current is too large (reaches the preset upper current limit), the current detection resistor reaches the threshold voltage of the triode when detecting the voltage of 0.7V, the current detection triode is triggered to be conducted, an overcurrent low-voltage signal is provided for the feedback circuit or the control circuit to execute power supply overcurrent protection, the power supply is turned off, and the power supply can be restarted after the overcurrent abnormality of the electric equipment is relieved. The resistance of the current detection resistor can be adjusted according to the preset current upper limit required by a specific circuit, so that the voltage at two ends of the current detection resistor is 0.7V when the preset current upper limit is reached.
The above embodiments and drawings are not intended to limit the form and style of the present invention, and any suitable changes or modifications made by those skilled in the art should not be construed as departing from the scope of the present invention.
Claims (5)
1. An over-current detection circuit, characterized in that: the current detection circuit comprises a current detection resistor R1, a current detection triode Q1, a current limiting resistor R2 and a current limiting resistor R3; one end of the current detection resistor R1 is connected with the emitting electrode of the current detection triode Q1 and serves as the input end of the overcurrent detection circuit, the other end of the current detection resistor R1 is connected with one end of the current limiting resistor R2 and serves as the output end of the overcurrent detection circuit, the other end of the current limiting resistor R2 is connected with the base electrode of the current detection triode Q1, the collector electrode of the current detection triode Q1 is connected with one end of the current limiting resistor R3, and the other end of the current limiting resistor R3 serves as the control end of the overcurrent detection circuit.
2. The overcurrent detection circuit of claim 1, wherein: and the input end of the over-current detection circuit is connected with the output end of a power supply to be protected.
3. The overcurrent detection circuit of claim 2, wherein: the power supply to be protected comprises a transformer T, a capacitor C1 and a diode D1, one end of a secondary winding of the transformer T is connected with one end of the capacitor C1 and serves as an output end of the power supply to be protected, the other end of the capacitor C1 is connected with an anode of the diode D1 and is grounded, and a cathode of the diode D1 is connected with the other end of the secondary winding of the transformer T.
4. The overcurrent detection circuit of claim 1, wherein: and the control end of the over-current detection circuit is connected with the control circuit.
5. The overcurrent detection circuit of claim 1, wherein: the current detection triode Q1 is an NPN triode.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921981296.4U CN211856718U (en) | 2019-11-17 | 2019-11-17 | Overcurrent detection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921981296.4U CN211856718U (en) | 2019-11-17 | 2019-11-17 | Overcurrent detection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN211856718U true CN211856718U (en) | 2020-11-03 |
Family
ID=73219888
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201921981296.4U Active CN211856718U (en) | 2019-11-17 | 2019-11-17 | Overcurrent detection circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN211856718U (en) |
-
2019
- 2019-11-17 CN CN201921981296.4U patent/CN211856718U/en active Active
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| PE01 | Entry into force of the registration of the contract for pledge of patent right | ||
| PE01 | Entry into force of the registration of the contract for pledge of patent right |
Denomination of utility model: An over current detection circuit Effective date of registration: 20210625 Granted publication date: 20201103 Pledgee: Xiamen Huli District Financing Guarantee Co.,Ltd. Pledgor: XIAMEN CASTEC ELECTRONIC INDUSTRY Co.,Ltd. Registration number: Y2021980005256 |