CN210490445U

CN210490445U - Input overvoltage protection module and terminal equipment

Info

Publication number: CN210490445U
Application number: CN201921469022.7U
Authority: CN
Inventors: 甘胜滨; 莫文林
Original assignee: Shenzhen Weibu Information Co Ltd
Current assignee: Shenzhen Weibu Information Co Ltd
Priority date: 2019-09-05
Filing date: 2019-09-05
Publication date: 2020-05-08
Anticipated expiration: 2029-09-05

Abstract

The embodiment of the utility model discloses an input overvoltage protection module and terminal equipment, wherein the terminal equipment comprises a circuit board, and a power socket and the input overvoltage protection module are arranged on the circuit board; the input overvoltage protection module is connected with the power socket; when the input overvoltage protection module judges that the input voltage output by the power socket is within a preset range, filtering the input voltage after delaying for a preset time, generating an output voltage and outputting the output voltage; and when the input voltage is judged to be larger than the upper limit value of the preset range, the output of the input voltage is cut off. When the input voltage is normal, the output voltage is normally output; when the input voltage exceeds the limit value of the designed input voltage of the product, the voltage output is cut off in time, and the product or the circuit can be protected from being burnt.

Description

Input overvoltage protection module and terminal equipment

Technical Field

The utility model relates to the field of electronic technology, especially, relate to an input overvoltage protection module and terminal equipment.

Background

At present, most of input overvoltage protection circuits have complicated circuit structures, high cost and large occupied PCB space; when some input voltage exceeds the limit voltage of the product, the power supply cannot be turned off in time.

SUMMERY OF THE UTILITY MODEL

To the technical problem, the embodiment of the utility model provides an input overvoltage protection module and terminal equipment are provided to solve current input overvoltage protection circuit when input voltage surpasses the extreme voltage of product, can not in time close the problem of power.

The embodiment of the utility model provides an input overvoltage protection module, which is connected with a power socket and comprises a detection circuit, a switch circuit and a filter circuit; the detection circuit is connected with the power socket and the switch circuit, and the switch circuit is connected with the filter circuit;

when the detection circuit judges that the input voltage output by the power socket is within a preset range, the control switch circuit outputs the input voltage after delaying for a preset time, and the filter circuit generates and outputs the output voltage after filtering the input voltage; and when the detection circuit judges that the input voltage is larger than the upper limit value of the preset range, the detection circuit controls the switch circuit to disconnect the output of the input voltage.

Optionally, in the input overvoltage protection module, the detection circuit includes a first capacitor, a first zener diode, a first resistor, a second resistor, and a third resistor;

one end of the first capacitor is connected with a 1 st pin of the power socket, one end of the third resistor and the switch circuit; the other end of the first capacitor is connected with one end of the first resistor; the other end of the first resistor is connected with one end of the second resistor, the anode of the first voltage stabilizing diode and the switch circuit; the negative electrode of the first voltage stabilizing diode is connected with the other end of the third resistor, and the other end of the second resistor is connected with the switch circuit.

Optionally, in the input overvoltage protection module, the switch circuit includes a first triode, a first MOS transistor, a second MOS transistor, a fourth resistor, a fifth resistor, a sixth resistor, and a second capacitor;

the base electrode of the first triode is connected with the other end of the first resistor, and the emitting electrode of the first triode is connected with the other end of the second resistor and the ground; a collector of the first triode is connected with one end of the fourth resistor, one end of the fifth resistor and the grid of the first MOS tube; the other end of the fourth resistor is connected with one end of the third resistor, one end of the second capacitor, one end of the sixth resistor and the source electrode of the second MOS transistor; the grid electrode of the second MOS tube is connected with the other end of the second capacitor, the other end of the sixth resistor and the drain electrode of the first MOS tube, the drain electrode of the second MOS tube is connected with the filter circuit, and the source electrode of the first MOS tube is grounded.

Optionally, in the input overvoltage protection module, the switch circuit further includes a fuse, one end of the fuse is connected to the source of the second MOS transistor and the other end of the fourth resistor, and the other end of the fuse is connected to one end of the third resistor.

Optionally, in the input overvoltage protection module, the switch circuit further includes a third capacitor and a seventh resistor, one end of the third capacitor is connected to the gate of the first MOS transistor, the other end of the third capacitor is grounded, one end of the seventh resistor is connected to the drain of the first MOS transistor, and the other end of the seventh resistor is connected to the gate of the second MOS transistor.

Optionally, in the input overvoltage protection module, the filter circuit includes a fourth capacitor, a fifth capacitor, a second zener diode, and an eighth resistor;

one end of the fourth capacitor is connected with the negative electrode of the second voltage stabilizing diode and the drain electrode of the second MOS tube, and one end of the fifth capacitor is connected with the voltage output end, one end of the eighth resistor and one end of the second voltage stabilizing diode; the other end of the fifth capacitor is connected with the other end of the eighth resistor, the anode of the second voltage stabilizing diode, the other end of the fourth capacitor and the ground.

Optionally, in the input overvoltage protection module, the detection circuit further includes a sixth capacitor and a transient voltage suppressor; one end of the sixth capacitor is connected with the negative electrode of the transient voltage suppressor, the 1 st pin of the power socket and one end of the third resistor; the other end of the sixth capacitor and the anode of the transient voltage suppressor are both grounded.

A second aspect of the embodiment of the present invention provides a terminal device, including a circuit board, wherein a power socket is disposed on the circuit board, wherein the circuit board is further provided with the input overvoltage protection module, and the input overvoltage protection module is connected to the power socket;

when the input overvoltage protection module judges that the input voltage output by the power socket is within a preset range, filtering the input voltage after delaying for a preset time, generating an output voltage and outputting the output voltage; and when the input voltage is judged to be larger than the upper limit value of the preset range, the output of the input voltage is cut off.

In the technical scheme provided by the embodiment of the utility model, the terminal equipment comprises a circuit board, wherein the circuit board is provided with a power socket and an input overvoltage protection module; the input overvoltage protection module is connected with the power socket; when the input overvoltage protection module judges that the input voltage output by the power socket is within a preset range, filtering the input voltage after delaying for a preset time, generating an output voltage and outputting the output voltage; and when the input voltage is judged to be larger than the upper limit value of the preset range, the output of the input voltage is cut off. When the input voltage is normal, the output voltage is normally output; when the input voltage exceeds the limit value of the designed input voltage of the product, the voltage output is cut off in time, and the product or the circuit can be protected from being burnt.

Drawings

Fig. 1 is a schematic circuit diagram of an input overvoltage protection module according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. The embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts, belong to the protection scope of the present invention.

Referring to fig. 1, a terminal device provided in an embodiment of the present invention includes a circuit board (i.e., a motherboard), where an input overvoltage protection module 10 and a power socket J (or an adapter interface) are disposed on the circuit board; the power socket J (the model is DC-092) is connected with the input overvoltage protection module 10. When the input overvoltage protection module 10 judges that the input voltage output by the power socket J is within a preset range, filtering the input voltage after delaying for a preset time, generating an output voltage and outputting the output voltage; when the input voltage is judged to be larger than the upper limit value (the limit voltage of the input voltage) of the preset range, the output of the input voltage is cut off.

Thus, when receiving the input voltage in the normal range (i.e. the preset range), the output voltage is approximately equal to the voltage of the input voltage (the voltage drop of the filtering and MOS transistor is small and can be ignored)); when the input voltage exceeds the limit value of the input voltage designed by the product (when the product is possibly damaged), the voltage output is cut off in time, and the product or the circuit can be protected from being burnt. The input overvoltage protection module 10 is suitable for all terminal devices using dc power (adapter) input, the terminal devices may be terminals such as computers, all-in-one computers, PCs, and the like, and the main board corresponds to a computer main board, an all-in-one computer main board, a PC main board, and the like.

The input overvoltage protection module 10 comprises a detection circuit 100, a switch circuit 200 and a filter circuit 300; the detection circuit 100 is connected to the power socket J and the switch circuit 200, and the switch circuit 200 is connected to the filter circuit 300. When the detection circuit 100 judges that the input voltage output by the power socket is within the preset range, the control switch circuit 200 outputs the input voltage after delaying for the preset time, and the filter circuit 300 filters the input voltage to generate the output voltage and outputs the output voltage; when the detection circuit 100 determines that the input voltage is greater than the upper limit value of the preset range, the control switch circuit 200 disconnects the output of the input voltage.

Referring to fig. 1, the detection circuit 100 includes a first capacitor C1, a first zener diode CR1, a first resistor R1, a second resistor R2, and a third resistor R3; one end of the first capacitor C1 is connected with the 1 st pin of the power socket J, one end of the third resistor R3 and the switch circuit 200; the other end of the first capacitor C1 is connected with one end of a first resistor R1; the other end of the first resistor R1 is connected with one end of the second resistor R2, the anode of the first zener diode CR1 and the switch circuit 200; the cathode of the first voltage-stabilizing diode CR1 is connected with the other end of the third resistor R3, and the other end of the second resistor R2 is connected with the switch circuit 200; pins 2 to 5 of the power socket J are grounded.

The range adjustment of the input voltage is realized by adjusting the regulated voltage value of the first zener diode CR1 (the models that can be adopted include MM1Z6B2H, MM1Z15H, MM1Z22H, etc., the models can be selected according to the design input voltage). The input voltage is input from the power socket J, is divided by a first capacitor C1 (the capacitance value is preferably 1uF), a first resistor R1 (the resistance value is preferably 1K Ω) and a second resistor R2 (the resistance value is preferably 100K Ω), and then outputs a control signal of a corresponding level to control the on/off of the switch circuit 200, so that the dynamic detection of the input voltage is realized; therefore, the adjustment is more convenient, the input transient response is more sensitive, and the protection is more reliable. When the input voltage is overvoltage, the input voltage is divided by a third resistor R3 (the resistance value is preferably 1K omega), a first voltage-stabilizing diode CR1 and a second resistor R2, and a control signal of a corresponding level is output, so that the steady-state detection of the input voltage is realized; compared with the existing circuit, the circuit has simple structure, lower cost and wider input voltage range (the input voltage range is + 5V- + 35V). The instantaneous time constant magnitude is determined by the values of C1, R1, and R2.

The switch circuit 200 comprises a first triode Q1, a first MOS transistor QP1, a second MOS transistor QP2, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6 and a second capacitor C2; the base electrode of the first triode Q1 is connected with the other end of the first resistor R1, and the emitter electrode of the first triode Q1 is connected with the other end of the second resistor R2 and the ground; a collector of the first triode Q1 is connected with one end of the fourth resistor R4, one end of the fifth resistor R5 and the gate of the first MOS transistor QP 1; the other end of the fourth resistor R4 is connected with one end of the third resistor R3, one end of the second capacitor C2, one end of the sixth resistor R6 and the source electrode of the second MOS transistor QP 2; the gate of the second MOS transistor QP2 is connected to the other end of the second capacitor C2, the other end of the sixth resistor R6, and the drain of the first MOS transistor QP1, the drain of the second MOS transistor QP2 is connected to the filter circuit 300, and the source of the first MOS transistor QP1 is grounded.

The first triode Q1 is an NPN triode with the model of LMBT3904, the first MOS transistor QP1 is an NMOS transistor with the model of ME2N7002E, and the second MOS transistor QP2 is a PMOS transistor with the model of MDS3652 URH. When the first transistor Q1 is turned on, the gate voltage of the first MOS transistor QP1 is pulled low, the first MOS transistor QP1 is turned off to turn off the second MOS transistor QP2, and at this time, the output of the input voltage is turned off. When the first transistor Q1 is turned off, the gate voltage of the first MOS transistor QP1 is divided by R4 (with a resistance value of preferably 100K Ω) and R5 (with a resistance value of preferably 510K Ω), and the divided normal input voltage can turn on the first MOS transistor QP1, so that the second MOS transistor QP2 is turned on, and at this time, the input voltage is output to the filter circuit.

Preferably, in order to prevent the second MOS transistor QP2 from being damaged by the transient over-high spike voltage (which is important, whether the input voltage is output is determined by the on-off state thereof), the switch circuit 200 further includes a fuse F, one end of the fuse F is connected to the source of the second MOS transistor QP2 and the other end of the fourth resistor R4, and the other end of the fuse F is connected to one end of the third resistor R3. Thus, when instantaneous over-high peak voltage occurs, the fuse F is blown to play a protection role.

Preferably, in order to protect the first MOS transistor QP1 (which controls the second MOS transistor QP2 and also needs to be protected in an important manner), the switch circuit 200 further includes a third capacitor C3 and a seventh resistor R7, one end of the third capacitor C3 is connected to the gate of the first MOS transistor QP1, the other end of the third capacitor C3 is grounded, one end of the seventh resistor R7 is connected to the drain of the first MOS transistor QP1, and the other end of the seventh resistor R7 is connected to the gate of the second MOS transistor QP 2.

The filter circuit 300 comprises a fourth capacitor C4, a fifth capacitor C5, a second voltage-stabilizing diode CR2 and an eighth resistor R8; one end of the fourth capacitor C4 is connected to the cathode of the second zener diode CR2 and the drain of the second MOS transistor QP2, and one end of the fifth capacitor C5 is connected to a voltage output end (which transmits the output voltage + VUSB _ CONN _ FUSE to a corresponding circuit at the rear stage, which is the prior art), one end of the eighth resistor R8 and one end of the second zener diode CR 2; the other end of the fifth capacitor C5 is connected to the other end of the eighth resistor R8, the anode of the second zener diode CR2, the other end of the fourth capacitor C4 and ground.

The capacitance value of the fourth capacitor C4 is 10uF, the capacitance value of the fifth capacitor C5 is 22uF, and the resistance value of the eighth resistor R8 is 300 Ω. The waveform of the output voltage + VUSB _ CONN _ FUSE is smoother and more stable through a filter circuit consisting of a resistor and a capacitor.

Preferably, in order to make the input voltage more stable and avoid damage to the circuit by the surge pulse, the detection circuit 100 further includes a sixth capacitor C6 and a transient voltage suppressor TVS; one end of the sixth capacitor C6 is connected to the negative electrode of the transient voltage suppressor TVS, the 1 st pin of the power socket J, and one end of the third resistor R3; the other end of the sixth capacitor C6 and the positive electrode of the transient voltage suppressor TVS are both grounded.

With continued reference to fig. 1, the operating principle of the input overvoltage protection module is as follows:

when the input voltage is in the normal range, after the input voltage is divided from the 1 st pin of the power socket J through the first capacitor C1, the first resistor R1 and the second resistor R2, the transistor Q1 is controlled to be instantly turned on to operate, the collector C voltage of the transistor Q1 is pulled low (according to the principle that the voltage at two ends of the capacitor cannot be suddenly changed), the first MOS transistor QP1 cannot be turned on, the drain D voltage of the first MOS transistor QP1 is high at this time, so the second MOS transistor QP2 is in an off state (disconnected), the input voltage cannot be output, and therefore, even if the power supply is inserted at this time, the power supply cannot be powered on (the output voltage is generated) for a while. When the input voltage charges the third capacitor C3 through the fourth resistor R4 until the input voltage reaches the turn-on voltage of the first MOS transistor QP1, the first MOS transistor QP1 is turned on and controls the second MOS transistor QP2 to be turned on, the input voltage is output through the second MOS transistor QP2, and output voltage is generated after filtering through C4, C5 and R8, at the moment, the power is turned on, and therefore the function of delayed starting is achieved.

The voltage at the base B of the transistor Q1 is determined by the voltage division of the third resistor R3, the first zener diode CR1 and the second resistor R2. When the input voltage is overvoltage, the divided voltage exceeds the conducting voltage of the triode Q1 (the saturation conducting voltage is more than 0.5V), the triode Q1 is in saturation conduction, the voltage of the collector C is low, and the voltage of the drain D of the first MOS tube QP1 is high, so that the second MOS tube QP2 is in an off state, the circuit is locked, the output voltage cannot be output, namely, when the input voltage exceeds the limit voltage of a product, the power supply is cut off, and the product is protected from being damaged.

To sum up, the input overvoltage protection module and the terminal device provided by the utility model cut off the power supply when the input voltage exceeds the limit voltage of the product, protect the product from being damaged, and then cut off the input voltage to restore the product to the normal state, and the product can also work normally when the normal voltage is connected; the circuit structure is simple, and the occupied space of the PCB is small, so that the cost is saved.

The above embodiments are only used to illustrate the technical solution of the present invention, and not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the present invention in its corresponding aspects.

Claims

1. An input overvoltage protection module is connected with a power socket and is characterized by comprising a detection circuit, a switch circuit and a filter circuit; the detection circuit is connected with the power socket and the switch circuit, and the switch circuit is connected with the filter circuit;

2. The input overvoltage protection module according to claim 1, wherein the detection circuit comprises a first capacitor, a first zener diode, a first resistor, a second resistor, and a third resistor;

3. The input overvoltage protection module according to claim 2, wherein the switching circuit comprises a first triode, a first MOS (metal oxide semiconductor) transistor, a second MOS transistor, a fourth resistor, a fifth resistor, a sixth resistor and a second capacitor;

4. The input overvoltage protection module according to claim 3, wherein the switch circuit further comprises a fuse, one end of the fuse is connected to the source of the second MOS transistor and the other end of the fourth resistor, and the other end of the fuse is connected to one end of the third resistor.

5. The input overvoltage protection module according to claim 3, wherein the switch circuit further comprises a third capacitor and a seventh resistor, one end of the third capacitor is connected to the gate of the first MOS transistor, the other end of the third capacitor is grounded, one end of the seventh resistor is connected to the drain of the first MOS transistor, and the other end of the seventh resistor is connected to the gate of the second MOS transistor.

6. The input overvoltage protection module according to claim 3, wherein the filter circuit comprises a fourth capacitor, a fifth capacitor, a second zener diode, and an eighth resistor;

7. The input overvoltage protection module of claim 2, wherein the detection circuit further comprises a sixth capacitor and a transient voltage suppressor; one end of the sixth capacitor is connected with the negative electrode of the transient voltage suppressor, the 1 st pin of the power socket and one end of the third resistor; the other end of the sixth capacitor and the anode of the transient voltage suppressor are both grounded.

8. A terminal device comprising a circuit board on which a power socket is provided, characterized in that an input overvoltage protection module according to any one of claims 1 to 7 is further provided; the input overvoltage protection module is connected with the power socket;