CN212935557U

CN212935557U - Super capacitor protection circuit with adjustable discharge current

Info

Publication number: CN212935557U
Application number: CN202022171166.3U
Authority: CN
Inventors: 丁进科; 刘再松; 李幼峰; 杨若; 洒国栋; 彭云华; 马静
Original assignee: Guilin Zhiyuan Power Electronics Co ltd
Current assignee: Guilin Zhiyuan Power Electronics Co ltd
Priority date: 2020-09-28
Filing date: 2020-09-28
Publication date: 2021-04-09
Anticipated expiration: 2030-09-28

Abstract

The utility model discloses a discharge current adjustable super capacitor protection circuit, which comprises a voltage comparison circuit, a discharge circuit, a temperature detection circuit and a fault output circuit which are connected in sequence; the voltage comparison circuit, the discharge circuit, the temperature detection circuit and the fault output circuit are all connected with a super capacitor, a diode D2 is connected between the voltage comparison circuit and the discharge circuit, a capacitor C2 is connected between the discharge circuit and the temperature detection circuit, the circuit determines a protection threshold value through a reference voltage reference and a comparator, the output end of the comparator is connected with a triode to control a discharge MOS (metal oxide semiconductor) tube group to carry out protection discharge, different maximum discharge currents can be realized by configuring a discharge resistor, the number of MOS tubes and the number of discharge resistors of the discharge circuit can be increased or decreased as well, more flexible configuration is realized, and the triode of the overcurrent protection circuit of the discharge circuit limits the maximum discharge current by detecting the voltage of the discharge resistor.

Description

Super capacitor protection circuit with adjustable discharge current

Technical Field

The utility model relates to a protection circuit specifically is a super capacitor protection circuit with adjustable discharge current.

Background

In the super capacitor energy storage device, a large number of super capacitors are often required to be connected in series, due to the inherent difference between the super capacitors, the voltage divided by each capacitor is different in the charging process, which may cause the voltage of each capacitor to exceed the maximum withstand voltage and damage the capacitor, and at this time, a protection circuit is required to discharge the capacitor exceeding the safe voltage so as to reduce the voltage of the capacitor and avoid damage.

The existing protection circuit has inflexible discharge parameters and small discharge capacity, and is difficult to deal with the scene of flexible application of the super capacitor.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing a super capacitor protection circuit with adjustable discharge current to solve the problem that proposes in the above-mentioned background art.

In order to achieve the above object, the utility model provides a following technical scheme:

a discharge current adjustable super capacitor protection circuit comprises a voltage comparison circuit, a discharge circuit, a temperature detection circuit and a fault output circuit which are connected in sequence; the voltage comparison circuit, the discharge circuit, the temperature detection circuit and the fault output circuit are all connected with the super capacitor, a diode D2 is connected between the voltage comparison circuit and the discharge circuit, and a capacitor C2 is connected between the discharge circuit and the temperature detection circuit.

The voltage comparison circuit comprises a comparator U1A, wherein a pin 1 of the current-voltage converter is connected with a resistor R5 and a diode D1, a pin 2 of the comparator U1A is connected with a resistor R3, a resistor R4 and a capacitor C1, and a pin 3 of the comparator U1A is connected with a resistor R1, a resistor R2 and a zener diode Q1; the discharging circuit comprises a triode Q2, a triode Q3 and a discharging MOS tube QL1, wherein the triode Q2 is connected with a resistor R6 and a resistor R7, a resistor R8 and a resistor R9 are connected between the triode Q2 and the triode Q3, a resistor R11 and a gate resistor RG1 are connected between the triode Q3 and the discharging MOS tube QL1, the discharging MOS tube QL1 is also connected with a discharging resistor RL1, and the discharging MOS tube QL1 is a low-voltage MOS tube BSC046N02 KSG; the temperature detection circuit comprises a comparator U1B, a resistor R18 and a resistor R19 are connected to the reverse input end of the comparator U1B in a voltage division mode, a resistor R20 and a thermistor NTC1 are connected to the positive input end of the comparator U1B in a voltage division mode, and the NTC1 is a negative temperature coefficient thermistor and is arranged near an electrode close to a super capacitor; the fault output circuit comprises a triode Q4 and an optocoupler U10, the triode Q4 is connected with a resistor R22, a resistor R23 and a resistor R24, and a resistor R24 is connected with a voltage reduction diode D3; the triode Q2 and the triode Q4 are PNP type triodes, and the triode Q3 is NPN type triodes.

As the preferred scheme of the utility model: the discharge circuit is also provided with a discharge MOS tube QL2 and a discharge MOS tube QL3 which are connected with the discharge MOS tube QL1 in parallel, the discharge MOS tube QL1, the discharge MOS tube QL2 and the discharge MOS tube QL3 are all connected with a triode Q3, the discharge MOS tube QL2 is connected with a gate resistor RG2 and a discharge resistor RL2, and the discharge MOS tube QL3 is connected with a gate resistor RG3 and a discharge resistor RL 3.

Compared with the prior art, the beneficial effects of the utility model are that: the circuit determines a protection threshold value through a reference voltage reference and a comparator, the output end of the comparator is connected with a triode to control a discharge MOS tube group to carry out protection discharge, different maximum discharge currents can be realized by configuring a discharge resistor, the number of MOS tubes and the number of the discharge resistors of the discharge circuit can be increased and decreased as well, greater flexible configuration is realized, the triode of an over-current protection circuit of the discharge circuit limits the maximum discharge current by detecting the voltage of the discharge resistor, in addition, the detection of overhigh temperature of a super capacitor is realized by installing an NTC thermistor close to an electrode, both overvoltage and overtemperature realize the output of faults by controlling the triode of a fault output circuit, and the fault output adopts optical coupler to isolate output so as to prevent the circuit formed by external wiring from causing accidental short circuit and ensure safety.

1. The utility model has the functions of over-voltage discharge protection and discharge current limiting; the reliability of the super capacitor device is improved.

2. To the super capacitor of different models, perhaps different charge-discharge parameter requirements, the utility model discloses a discharge circuit can dispose in a flexible way.

3. The utility model comprises the isolation output function of the overvoltage fault and the overtemperature fault of the super capacitor; the safety and the maintainability of the super capacitor device are improved.

Drawings

Fig. 1 is an overall circuit diagram of the present invention.

Fig. 2 is a diagram of the discharge circuit expansion 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. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Example 1:

referring to fig. 1, a super capacitor protection circuit with adjustable discharge current includes a voltage comparison circuit, a discharge circuit, a temperature detection circuit and a fault output circuit, which are connected in sequence, and when the circuit is connected to two stages of super capacitors, the super capacitors are used as a power source of the circuit; the voltage comparison circuit, the discharge circuit, the temperature detection circuit and the fault output circuit are all connected with the super capacitor, a diode D2 is connected between the voltage comparison circuit and the discharge circuit, and a capacitor C2 is connected between the discharge circuit and the temperature detection circuit.

The voltage comparison circuit comprises a comparator U1A, a pin 1 of the current-voltage converter is connected with a resistor R5 and a diode D1, a pin 2 of the comparator U1A is connected with a resistor R3, a resistor R4 and a capacitor C1, a pin 3 of the comparator U1A is connected with a resistor R1, a resistor R2 and a zener diode Q1, the zener diode Q1 is used for providing a 1.2V voltage reference as a reference voltage, the voltage divided by the resistor R3 and the resistor R4 is compared with the reference voltage, when the super capacitor voltage exceeds a designed protection value, the pin 1 of the comparator U1A is changed into a low level to complete a voltage comparison function, and the resistor R5 enables the comparison circuit to be in a hysteresis comparison mode to avoid frequent operation of a critical point.

The discharge circuit comprises a triode Q2, a triode Q3 and a discharge MOS tube QL1, wherein the triode Q2 is connected with a resistor R6 and a resistor R7, a resistor R8 and a resistor R9 are connected between the triode Q2 and the triode Q3, a resistor R11 and a gate resistor RG1 are connected between the triode Q3 and the discharge MOS tube QL1, the discharge MOS tube QL1 is also connected with a discharge resistor RL1, when the 1 pin 1 of a comparator U1A in the voltage comparison circuit is changed into low level, the triode Q2 is conducted by the division of the resistor R6 and the resistor R7, the VG voltage is increased, the discharge MOS tube QL1 is turned on, the discharge MOS tube KSQL 1 is a low-voltage MOS tube BSC046N 02G, the drain current of the BSC046N02KSG can reach 80A at most, the Vgh voltage is typically 0.95V, the transistor can work near the maximum withstand voltage of a common capacitor, the discharge current can flow through the discharge resistor RL 7, the VR resistor Q1 and the VR can reduce the turn-on voltage of the triode Q3, therefore, the discharge MOS tube QL1 is prevented from increasing the discharge current continuously, negative feedback is formed, the limitation on the maximum discharge current is realized, the discharge current is controlled by configuring the parameters of the discharge resistor RL1, and the requirements of different devices are met.

The temperature detection circuit comprises a comparator U1B, a resistor R18 and a resistor R19 are connected to the reverse input end of the comparator U1B in a voltage division mode, a resistor R20 and a thermistor NTC1 are connected to the positive input end of the comparator U1B in a voltage division mode, NTC1 is a negative temperature coefficient thermistor and is installed near an electrode close to a super capacitor, the resistance value of the thermistor NTC1 is reduced along with the increase of the temperature of the capacitor, and when the ratio of the value of the resistance to the resistor R20 is smaller than the ratio of the resistor R19 to the resistor R18, a pin 7 of the comparator U1B is turned from a high level to a low level to realize an overvoltage detection function; the resistor R5 makes the comparison circuit become hysteresis comparison, and avoids the frequent operation of the critical point.

The fault output circuit comprises a triode Q4 and an optocoupler U10, the triode Q4 is connected with a resistor R22, a resistor R23 and a resistor R24, the resistor R24 is connected with a voltage reduction diode D3, when the super capacitor is in overvoltage, the pin 1 of the comparator U1A becomes low level, current flows through the resistor R22, the resistor R23, the voltage reduction diode D3 and the diode D1, voltage drop is formed on the resistor R22, the triode Q4 is conducted, the diode side of the optocoupler U10 is short-circuited, the output is disconnected, fault output is achieved, similarly, the pin 7 of the comparator U1B becomes low level when the temperature is over-high, fault output is achieved in the same mode through the voltage reduction diode D3, and mutual influence among circuits can be prevented by using the one-way conduction characteristics of the diode D1, the diode D2 and the voltage reduction diode D3.

The triode Q2 and the triode Q4 are PNP type triodes, and the triode Q3 is NPN type triodes.

Example 2:

as shown in fig. 2, in addition, in order to obtain a larger discharge capacity, it can be realized by increasing the number of the discharge MOS transistors and the discharge resistors, that is, the discharge circuit further has a discharge MOS transistor QL2 and a discharge MOS transistor QL3 connected in parallel with the discharge MOS transistor QL1, the discharge MOS transistor QL1, the discharge MOS transistor QL2 and the discharge MOS transistor QL3 are all connected with a triode Q3, the discharge MOS transistor QL2 is connected with a gate resistor RG2 and a discharge resistor RL2, and the discharge MOS transistor QL3 is connected with a gate resistor RG3 and a discharge resistor RL 3.

It is obvious to a person skilled in the art that the invention is not restricted to details of the above-described exemplary embodiments, but that it can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.

Claims

1. A super capacitor protection circuit with adjustable discharge current is characterized by comprising a voltage comparison circuit, a discharge circuit, a temperature detection circuit and a fault output circuit which are sequentially connected; the voltage comparison circuit, the discharge circuit, the temperature detection circuit and the fault output circuit are all connected with a super capacitor, a diode D2 is connected between the voltage comparison circuit and the discharge circuit, the voltage comparison circuit comprises a comparator U1A, a pin 1 of the current-voltage converter is connected with a resistor R5 and a diode D1, a pin 2 of the comparator U1A is connected with a resistor R3, a resistor R4 and a capacitor C1, and a pin 3 of the comparator U1A is connected with a resistor R1, a resistor R2 and a zener diode Q1; the discharging circuit comprises a triode Q2, a triode Q3 and a discharging MOS tube QL1, wherein the triode Q2 is connected with a resistor R6 and a resistor R7, a resistor R8 and a resistor R9 are connected between the triode Q2 and the triode Q3, a resistor R11 and a gate resistor RG1 are connected between the triode Q3 and the discharging MOS tube QL1, and the discharging MOS tube QL1 is also connected with a discharging resistor RL 1; the temperature detection circuit comprises a comparator U1B, a resistor R18 and a resistor R19 are connected to the reverse input end of the comparator U1B in a voltage division mode, and a resistor R20 and a thermistor NTC1 are connected to the forward input end of the comparator U1B in a voltage division mode; the fault output circuit comprises a triode Q4 and an optocoupler U10, the triode Q4 is connected with a resistor R22, a resistor R23 and a resistor R24, and the resistor R24 is connected with a voltage reduction diode D3.

2. The discharge current adjustable super capacitor protection circuit as claimed in claim 1, wherein a capacitor C2 is connected between the discharge circuit and the temperature detection circuit.

3. The discharge current adjustable super capacitor protection circuit as claimed in claim 1, wherein the discharge MOS transistor QL1 is a low voltage MOS transistor BSC046N02 KSG.

4. The discharge current adjustable supercapacitor protection circuit according to claim 1, wherein the NTC1 is a negative temperature coefficient thermistor and is mounted near an electrode of the supercapacitor.

5. A discharge current adjustable super capacitor protection circuit as claimed in any one of claims 1-4, wherein said transistor Q2 and transistor Q4 are PNP type transistors, and transistor Q3 is NPN type transistor.

6. A discharge current adjustable super capacitor protection circuit as claimed in any one of claims 1-4, wherein said discharge circuit further has a discharge MOS tube QL2 and a discharge MOS tube QL3 connected in parallel with the discharge MOS tube QL1, the discharge MOS tube QL1, the discharge MOS tube QL2 and the discharge MOS tube QL3 are all connected with a triode Q3, said discharge MOS tube QL2 is connected with a gate resistor RG2 and a discharge resistor RL2, said discharge MOS tube QL3 is connected with a gate resistor RG3 and a discharge resistor RL 3.