CN220857619U - Load protection circuit - Google Patents
Load protection circuit Download PDFInfo
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- CN220857619U CN220857619U CN202322484516.5U CN202322484516U CN220857619U CN 220857619 U CN220857619 U CN 220857619U CN 202322484516 U CN202322484516 U CN 202322484516U CN 220857619 U CN220857619 U CN 220857619U
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- protection circuit
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- 239000003990 capacitor Substances 0.000 claims abstract description 44
- 230000008878 coupling Effects 0.000 claims abstract description 25
- 238000010168 coupling process Methods 0.000 claims abstract description 25
- 238000005859 coupling reaction Methods 0.000 claims abstract description 25
- 230000005611 electricity Effects 0.000 description 5
- 238000010586 diagram Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 230000002159 abnormal effect Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
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Abstract
The utility model discloses a load protection circuit which is connected with a power supply circuit, wherein the power supply circuit comprises a power supply chip, a switch tube and a protocol chip, the load protection circuit is respectively connected with the power supply chip and the protocol chip, the load protection circuit comprises a coupling capacitor, a rectifying unit, a first triode and a second triode, a switch control pin of the power supply chip is connected with a base electrode of the first triode after passing through the coupling capacitor and the rectifying unit, a collector electrode of the first triode is electrically connected with the other end of a seventh resistor, one end of the collector electrode of the first triode is connected with the output end of the power supply circuit, the other ends of the collector electrode of the first triode and the seventh resistor are both connected with the base electrode of the second triode, the emitters of the first triode and the second triode are both grounded, the base electrode of the first triode is electrically connected with an eleventh resistor grounded one by one, and the collector electrode of the second triode is connected with the output pin of the protocol chip and the control end of the switch tube after passing through an eighth resistor.
Description
Technical Field
The utility model relates to the technical field of power protection, in particular to a load protection circuit.
Background
A protocol chip is an integrated circuit chip that manages and controls the current and voltage during charging. The protocol chip can adjust the output of current and voltage in real time according to the communication protocol between the charging equipment and the power supply so as to charge quickly and efficiently. The existing quick-charging equipment on the market mainly has two circuit structures, one is that a protocol chip is only responsible for adjusting the feedback of a DC-DC power supply chip so as to control the output voltage of the DC-DC power supply chip to rise or fall, and the circuit has simple structure and lower cost, but cannot prevent the DC-DC power supply chip from being short-circuited, so that the risk of damaging the load electronic equipment exists; the other is that the protocol chip is responsible for adjusting the feedback of the DC-DC power supply chip and is added with the MOS tube as a switch, when abnormal conditions such as overcurrent, overvoltage or overtemperature occur, the MOS tube can be closed to protect the load electronic equipment, but the response time of the protocol chip is limited, when the DC-DC power supply chip is short-circuited, the output still has high voltage of about tens milliseconds or one hundred milliseconds, or because the voltage withstand of the protocol chip is limited, the protocol chip is short-circuited when the voltage is high, the overvoltage protection function is invalid, and the load electronic equipment is still damaged. Therefore, the circuit structure of the existing quick-charging device has the risk of damaging the load electronic device, and serious accidents such as heating and firing of the battery of the load can be caused.
Disclosure of utility model
The utility model aims to provide a load protection circuit for protecting load electronic equipment when an input/output short circuit occurs to a power supply chip.
In order to solve the technical problems, the aim of the utility model is realized by the following technical scheme: the utility model provides a load protection circuit, with power supply circuit electricity is connected, power supply circuit includes power supply chip, switch tube and agreement chip, load protection circuit respectively with power supply chip with the agreement chip links to each other, load protection circuit includes coupling capacitor, rectifier unit, first triode and second triode, power supply chip's switch control pin is through coupling capacitor with behind the rectifier unit with the base of first triode links to each other, the collecting electrode of first triode with one end with the other end electricity of the seventh resistance that power supply circuit's output links to each other is connected, the collecting electrode of first triode with the other end of seventh resistance all with the base of second triode links to each other, first triode with the projecting pole of second triode all is grounded, the base electricity of first triode is connected with the eleventh resistance of one-to-one ground, the base electricity of second triode is connected with the tenth resistance of one-to-one ground, the collecting electrode of second triode is through an eighth resistance after with the output of the chip and agreement pin link to each other.
The further technical scheme is as follows: the rectifying unit comprises a rectifying diode, two ends of the coupling capacitor are respectively connected with the switch control pin of the power chip and the anode of the rectifying diode, and the cathode of the rectifying diode is connected with the base electrode of the first triode.
The further technical scheme is as follows: and the cathode of the rectifier diode is connected with the base electrode of the first triode after passing through a base electrode current limiting resistor.
The further technical scheme is as follows: the rectifying unit further comprises a sixth capacitor which is grounded one by one, the cathode of the rectifying diode and one end of the base current limiting resistor are connected with the other end of the sixth capacitor, and the other end of the base current limiting resistor is connected with the base of the first triode.
The further technical scheme is as follows: and one end of the coupling capacitor, which is connected with the anode of the rectifying diode, is electrically connected with a discharge unit.
The further technical scheme is as follows: the bleeder unit comprises a third diode, the cathode of the third diode is connected with one end of the coupling capacitor, which is connected with the anode of the rectifying diode, and the anode of the third diode is grounded.
The further technical scheme is as follows: and the cathode of the rectifier diode and one end of the base current limiting resistor are connected with the other end of the twelfth resistor which is grounded one by one.
The further technical scheme is as follows: the switching tube is a MOS tube, a reset starting pin and a feedback pin of the power chip are respectively connected with a drain electrode of the switching tube and a feedback pin of the protocol chip, a grid electrode of the switching tube is connected with a collector electrode of the second triode and an output pin of the protocol chip, a third resistor is electrically connected between the source electrode and the grid electrode of the switching tube, and one end of the third resistor is connected with the output pin of the protocol chip.
The further technical scheme is as follows: the reset starting pin of the power chip is connected with the drain electrode of the switching tube after passing through a first capacitor and a first inductor, one end of the first inductor is connected with one end of the first capacitor, and the other end of the first inductor and the drain electrode of the switching tube are connected with the output end of the power circuit.
The further technical scheme is as follows: and an input pin of the protocol chip is connected with an output end of the power supply circuit.
The beneficial technical effects of the utility model are as follows: the load protection circuit provided by the utility model is used for detecting the square wave of the switch control pin of the power chip of the power circuit by arranging the coupling capacitor, so that whether the power chip works normally or not is judged, when judging that the power chip is short-circuited, the switching tube on the power output bus of the power circuit is closed by utilizing the cooperation of the first triode and the second triode, the purpose of protecting load electronic equipment is achieved, a special protection chip is not needed, and the circuit is simple in structure and low in cost.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings required for the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present utility model, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a circuit diagram of a load protection circuit according to an embodiment of the present utility model;
fig. 2 is a circuit diagram of a power supply circuit electrically connected to the load protection circuit in practical application according to an embodiment of the present utility model.
Detailed Description
The following description of the embodiments of the present utility model will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are some, but not all embodiments of the utility model. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.
Referring to fig. 1 and 2, fig. 1 is a circuit diagram of a load protection circuit provided by the embodiment of the utility model, the load protection circuit 10 is electrically connected with the power circuit 20, the power circuit 20 includes a power chip U1, a switching transistor QT1 and a protocol chip U2, the load protection circuit 10 is respectively connected with the power chip U1 and the protocol chip U2, the load protection circuit 10 includes a coupling capacitor C5, a rectifying unit 11, a first triode T1 and a second triode T2, a switch control pin SW of the power chip U1 is connected with a base of the first triode T1 through the coupling capacitor C5 and the rectifying unit 11, a collector of the first triode T1 is electrically connected with another end of a seventh resistor R7 connected with an output terminal of the power circuit 20, a collector of the first triode T1 and another end of the seventh resistor R7 are respectively connected with the second triode T2, a base of the first triode T1 and the second triode T2 are electrically connected with the base of the first triode T2, a base of the first triode T2 is electrically connected with the base of the eighth triode T2, and the base of the second triode T2 is electrically connected with the base of the eighth triode R25.
The load refers to load electronic equipment, including notebook computers, smart phones or digital cameras, and the like, the start and stop of an output signal of the power supply circuit 20 can be controlled by setting a switching tube QT1, after the protocol chip U2 is communicated with the load electronic equipment, the voltage required by the load electronic equipment is obtained, the output voltage is increased by pulling the current of a feedback pin FB of the feedback pin FB, and after stable voltage is obtained, the switching tube QT1 is conducted so that the load electronic equipment obtains target voltage for charging. By setting the coupling capacitor C5 so that the ac voltage passes but the dc voltage cannot pass, the rectification unit 11 rectifies the ac power passing through the coupling capacitor C5 into dc power and then flows the dc power to the first transistor T1, and the eleventh resistor R11 and the tenth resistor R10 are pull-down resistors of the first transistor T1 and the second transistor T2, respectively. The load protection circuit 10 is configured to detect the square wave of the switch control pin SW of the power chip U1 of the power circuit 20 by setting the coupling capacitor C5, so as to determine whether the power chip U1 works normally, and when it is determined that the power chip U1 is short-circuited, the first triode T1 and the second triode T2 are matched to close the switch tube QT1 on the power output bus of the power circuit 20, so as to achieve the purpose of protecting the load electronic device, and no special protection chip is required.
Specifically, in this embodiment, the rectifying unit 11 includes a rectifying diode D2, two ends of the coupling capacitor C5 are respectively connected to the switch control pin SW of the power chip U1 and the anode of the rectifying diode D2, and the cathode of the rectifying diode D2 is connected to the base of the first triode T1.
Specifically, in this embodiment, the cathode of the rectifying diode D2 is connected to the base of the first triode T1 through a base current limiting resistor R9, so that the cathode of the rectifying diode D2 is connected to one end of the base current limiting resistor R9, and the base of the first triode T1 is connected to the other end of the base current limiting resistor R9, so as to perform a current limiting function on the electric signal flowing into the first triode T1.
Specifically, in this embodiment, the rectifying unit 11 further includes a sixth capacitor C6 connected to one end to ground, where the cathode of the rectifying diode D2 and one end of the base current limiting resistor R9 are connected to the other end of the sixth capacitor C6, and the other end of the base current limiting resistor R9 is connected to the base of the first triode T1, so as to store energy through the sixth capacitor C6, and change the pulsating direct current rectified by the rectifying diode D2 into a stable direct current.
Specifically, in this embodiment, a bleed unit is electrically connected to one end of the coupling capacitor C5 connected to the anode of the rectifying diode D2.
Specifically, in this embodiment, the bleeder unit includes a third diode D3, where a cathode of the third diode D3 is connected to an end of the coupling capacitor C5 connected to an anode of the rectifying diode D2, and an anode of the third diode D3 is grounded to provide a bleeder path for energy of the coupling capacitor C5.
Specifically, in this embodiment, the cathode of the rectifying diode D2 and one end of the base current limiting resistor R9 are connected to the other end of the twelfth resistor R12, which is grounded one by one.
Specifically, in this embodiment, the switching tube QT1 is a MOS tube, the reset start pin BOOT and the feedback pin FB of the power chip U1 are respectively connected with the drain of the switching tube QT1 and the feedback pin FB of the protocol chip U2, the gate of the switching tube QT1 is connected with the collector of the second triode T2 and the output pin VOUTIG of the protocol chip U2, and a third resistor R3 is electrically connected between the source and the gate of the switching tube QT1 to prevent external interference, so that the switching tube QT1 is turned off more stably and reliably, and one end of the third resistor R3 is connected with the output pin VOUTIG of the protocol chip U2. The switching tube QT1 is specifically an NMOS tube, when the voltage between the gate and the source of the switching tube QT1 is at a high level, the switching tube QT1 is turned on, and when the voltage between the gate and the source of the switching tube QT1 is at a low level, the switching tube QT1 is turned off.
Specifically, in this embodiment, the reset start pin BOOT of the power chip U1 is connected to the drain of the switching tube QT1 through a first capacitor C1 and a first inductor L1, one end of the first inductor L1 is connected to one end of the first capacitor C1, and the other end of the first inductor L1 and the drain of the switching tube QT1 are both connected to the output end VOUT of the power circuit 20. The first capacitor C1 is a bootstrap capacitor of the power chip U1, and the on/off of the power chip U1 may cause the first capacitor C1 to be charged and discharged, and the charged electricity of the first capacitor C1 may be used for driving an internal switching tube of the power chip U1. When the power chip U1 is turned on, the first inductor L1 stores energy, and when the power chip U1 is turned off, the first inductor L1 releases energy to play a role in follow current. The input pin of the power chip U1 is connected with the input end of the power circuit, and one end of the first inductor L1 and one end of the first capacitor C1 are connected with the switch control pin SW of the power chip U1.
Specifically, in the present embodiment, the input pin VIN of the protocol chip U2 is connected to the output terminal VOUT of the power circuit 20.
Based on the design, when the power supply chip works normally, a square wave generated by a switch exists on a switch control pin of the power supply chip, the square wave represents generated voltage alternating voltage, at the moment, the square wave is rectified by a rectifier diode after passing through a coupling capacitor and stored by a sixth capacitor to generate stable direct current, the direct current flows into a base electrode of a first triode after passing through a base electrode current limiting resistor, the base electrode of the first triode has forward current to pass through, so that a collector electrode and an emitter electrode of the first triode are conducted, the first triode is conducted, the collector electrode of the first triode is pulled to 0V, the base electrode of a second triode is 0V, the second triode is cut off, and a switch tube on a power output bus of the power supply circuit is conducted, so that the power supply circuit normally outputs an electric signal to load electronic equipment to supply power for the load electronic equipment, and the load electronic equipment works normally; if the power chip is short-circuited, the switch control pin of the power chip generates stable power supply voltage, the stable power supply voltage represents that the generated voltage is direct current voltage, at the moment, the power supply voltage cannot pass through the coupling capacitor, the base electrode of the first triode does not flow through current, the first triode is cut off, the base electrode of the second triode is pulled up to the power supply by a seventh resistor with one end connected with the output end of the power supply circuit, the second triode is turned on, the eighth resistor is pulled to 0V, and the switching tube on the power supply output bus of the power supply circuit is cut off, so that the power supply effect of load electronic equipment is achieved.
In summary, the load protection circuit of the present utility model detects the square wave of the switch control pin of the power chip of the power circuit by setting the coupling capacitor, so as to determine whether the power chip works normally, and when it is determined that the power chip is short-circuited, the first triode and the second triode are used to close the switch tube on the power output bus of the power circuit in cooperation, so as to achieve the purpose of protecting the load electronic equipment.
While the utility model has been described with reference to certain preferred embodiments, it will be understood by those skilled in the art that various changes and substitutions of equivalents may be made and equivalents will be apparent to those skilled in the art without departing from the scope of the utility model. Therefore, the protection scope of the utility model is subject to the protection scope of the claims.
Claims (10)
1. The load protection circuit is characterized by being electrically connected with a power supply circuit, the power supply circuit comprises a power supply chip, a switch tube and a protocol chip, the load protection circuit is respectively connected with the power supply chip and the protocol chip, the load protection circuit comprises a coupling capacitor, a rectifying unit, a first triode and a second triode, a switch control pin of the power supply chip is connected with a base electrode of the first triode after passing through the coupling capacitor and the rectifying unit, a collector electrode of the first triode is electrically connected with the other end of a seventh resistor with one end connected with an output end of the power supply circuit, a collector electrode of the first triode and the other end of the seventh resistor are all connected with a base electrode of the second triode, an eleventh resistor with one-to-one ground is electrically connected with a base electrode of the first triode, a base electrode of the second triode is electrically connected with a tenth resistor with one-to-ground, and a collector electrode of the second triode is electrically connected with the control pin of the switch tube after passing through an eighth resistor.
2. The load protection circuit of claim 1, wherein the rectifying unit comprises a rectifying diode, two ends of the coupling capacitor are respectively connected with the switch control pin of the power supply chip and an anode of the rectifying diode, and a cathode of the rectifying diode is connected with a base electrode of the first triode.
3. The load protection circuit of claim 2, wherein the cathode of the rectifying diode is connected to the base of the first triode through a base current limiting resistor.
4. The load protection circuit of claim 3, wherein the rectifying unit further comprises a sixth capacitor connected to one end, the cathode of the rectifying diode and one end of the base current limiting resistor are connected to the other end of the sixth capacitor, and the other end of the base current limiting resistor is connected to the base of the first triode.
5. A load protection circuit according to claim 3, wherein a bleed unit is electrically connected to an end of the coupling capacitor connected to the anode of the rectifier diode.
6. The load protection circuit of claim 5, wherein the bleed unit comprises a third diode, a cathode of the third diode being connected to an end of the coupling capacitor connected to an anode of the rectifying diode, an anode of the third diode being grounded.
7. A load protection circuit according to claim 3, wherein the cathode of the rectifying diode and one end of the base current limiting resistor are connected to the other end of the twelfth resistor which is grounded one by one.
8. The load protection circuit of claim 1, wherein the switching tube is a MOS tube, the reset start pin and the feedback pin of the power supply chip are respectively connected with the drain electrode of the switching tube and the feedback pin of the protocol chip, the gate electrode of the switching tube is connected with the collector electrode of the second triode and the output pin of the protocol chip, a third resistor is electrically connected between the source electrode and the gate electrode of the switching tube, and one end of the third resistor is connected with the output pin of the protocol chip.
9. The load protection circuit of claim 8, wherein the reset enable pin of the power supply chip is connected to the drain of the switching tube through a first capacitor and a first inductor, one end of the first inductor is connected to one end of the first capacitor, and the other end of the first inductor and the drain of the switching tube are both connected to the output terminal of the power supply circuit.
10. The load protection circuit of claim 1, wherein an input pin of the protocol chip is connected to an output of the power circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202322484516.5U CN220857619U (en) | 2023-09-13 | 2023-09-13 | Load protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202322484516.5U CN220857619U (en) | 2023-09-13 | 2023-09-13 | Load protection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN220857619U true CN220857619U (en) | 2024-04-26 |
Family
ID=90743040
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202322484516.5U Active CN220857619U (en) | 2023-09-13 | 2023-09-13 | Load protection circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN220857619U (en) |
-
2023
- 2023-09-13 CN CN202322484516.5U patent/CN220857619U/en active Active
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