阅读说明：本技术 一种过流保护装置控制电路及其设计方法 (Control circuit of overcurrent protection device and design method thereof ) 是由 仇庆东 司马新 李鹏 周革强 于 2019-11-08 设计创作，主要内容包括：本发明涉及一种过流保护装置控制电路及其设计方法，所述控制电路包括电源模块、采样模块、阈值分析模块及执行保护模块；所述电源模块用于连接电连接器插座，用于将输入电压转换为采样模块和阈值分析模块的工作电压；所述采样模块用于连接电连接器插座，对输入的所述电连接器插座的输出信号进行采集；所述阈值分析模块连接采样模块，用于通过输入的电压差值进行工作状态控制；所述执行保护模块连接阈值分析模块，用于连接脱扣器，用于根据所述执行分析模块的输出信号控制脱扣器的工作状态。本发明能够根据待保护电路实际工作电流大小，给脱扣器线圈通电，产品触头系统与控制系统带动开关动作，延时断开或瞬间断开电路，保护后级电路。(The invention relates to a control circuit of an overcurrent protection device and a design method thereof, wherein the control circuit comprises a power module, a sampling module, a threshold analysis module and an execution protection module; the power supply module is used for connecting an electric connector socket and converting input voltage into working voltage of the sampling module and the threshold analysis module; the sampling module is used for connecting an electric connector socket and collecting input output signals of the electric connector socket; the threshold analysis module is connected with the sampling module and is used for controlling the working state through the input voltage difference value; the execution protection module is connected with the threshold analysis module, is used for connecting a release and is used for controlling the working state of the release according to the output signal of the execution analysis module. The invention can electrify the coil of the release according to the actual working current of the circuit to be protected, the product contact system and the control system drive the switch to act, and the circuit is disconnected in a delayed or instant manner, thereby protecting the rear-stage circuit.)

1. The control circuit of the over-current protection device is characterized by comprising a power supply module, a sampling module, a threshold value analysis module and an execution protection module;

the power supply module is used for connecting an electric connector socket and converting input voltage into working voltage of the sampling module and the threshold analysis module;

the sampling module is used for connecting an electric connector socket and collecting input output signals of the electric connector socket;

the threshold analysis module is connected with the sampling module and is used for controlling the working state through the input voltage difference value;

the execution protection module is connected with the threshold analysis module, is used for connecting a release and is used for controlling the working state of the release according to the output signal of the execution analysis module.

2. The overcurrent protection device control circuit of claim 1, wherein the power module comprises a transient suppression diode, a first filter circuit, a voltage regulator, and a second filter circuit, the transient suppression diode and the first filter circuit each being coupled between an input voltage and ground, the voltage regulator being coupled between the input voltage and the output operating voltage, the second filter circuit being coupled between the output operating voltage and ground.

3. The control circuit of claim 1, wherein the sampling module comprises a sampling resistor and an amplifier circuit, and the on-off node control is performed by controlling the current range flowing through the sampling resistor.

4. The overcurrent protection device control circuit of claim 1 wherein the threshold analysis module comprises a first comparator circuit, a second comparator circuit, a delay circuit and a third comparator circuit;

the non-inverting input ends of the first comparator circuit and the second comparator circuit are connected with the output end of the sampling module, and the inverting input end of the first comparator circuit and the second comparator circuit is connected with the output end of the power supply module after voltage division;

the non-inverting input end of the third comparator circuit is connected with the output end of the second comparator circuit, the inverting input end of the third comparator circuit is connected with the output end of the power module after voltage division, and a delay circuit is connected between the non-inverting input end and the inverting input end of the third comparator circuit.

5. The overcurrent protection device control circuit as recited in claim 4, wherein the executive protection module comprises a first diode, a second diode and a triode;

the anode of the first diode is connected with the output end of the first comparator circuit, and the cathode of the first diode is connected with the base electrode of the triode; the anode of the second diode is connected with the output end of the third comparator circuit, and the cathode of the second diode is connected with the base electrode of the triode; and the emitting electrode of the triode is connected with the ground wire, and the collecting electrode of the triode is connected with the release.

6. A design method of a control circuit of an overcurrent protection device is characterized by comprising the following steps:

a sampling module, a threshold analysis module and an execution protection module are sequentially arranged between the electric connector socket and the release;

the sampling module is used for collecting the input output signal of the electric connector socket; the threshold analysis module is used for controlling the working state through the input voltage difference value; the execution protection module is used for controlling the working state of the release according to the output signal of the execution analysis module.

7. The method of claim 6, further comprising: and a power supply module for providing working voltage is arranged between the electric connector socket and the sampling module and between the electric connector socket and the threshold value analysis module.

8. The design method of the control circuit of the over-current protection device according to claim 6, wherein the threshold analysis module comprises a first comparator circuit, a second comparator circuit, a delay circuit and a third comparator circuit;

the non-inverting input ends of the first comparator circuit and the second comparator circuit are connected with the output end of the sampling module, and the inverting input end of the first comparator circuit and the second comparator circuit is connected with the output end of the power supply module after voltage division; the non-inverting input end of the third comparator circuit is connected with the output end of the second comparator circuit, the inverting input end of the third comparator circuit is connected with the output end of the power module after voltage division, and a delay circuit is connected between the non-inverting input end and the inverting input end of the third comparator circuit.

The sampling module comprises a sampling resistor and an amplifier circuit, and on-off node control is carried out by controlling the current range flowing through the sampling resistor, specifically:

when the input current of the electric connector socket is less than 6.6A, the voltage U output by the amplifier circuit is less than the voltage of the inverting input ends of the second comparator circuit and the first comparator circuit, the comparators output low levels, the tripper does not have tripping action, and the switch is conducted;

when the input current of the electric connector socket is greater than 6.9A and less than 9.5A, the voltage U output by the amplifier circuit is greater than the voltage of the inverting input end of the second comparator circuit and less than the voltage of the inverting input end of the first comparator circuit, so that the first comparator circuit outputs a low level, the second comparator circuit outputs a high level, the delay circuit works, the capacitor starts to charge, and the third comparator outputs a high level to drive the release to disconnect the switch;

when the input current of the electric connector socket is larger than 10.5A, the voltage U output by the amplifier circuit is larger than the voltage of the inverting input end of the first comparator circuit, the first comparator circuit outputs high level, and the release is driven to disconnect the switch.

Technical Field

The invention relates to the technical field of overcurrent protection in a circuit structure, in particular to a control circuit of an overcurrent protection device and a design method thereof.

Background

The common overcurrent protection device in the market can only singly realize the function of automatically disconnecting the switch when the working current exceeds a certain limit, and can not realize two control functions of switch delay disconnection and instantaneous disconnection simultaneously according to the actual current flowing through the product and the working condition of the product.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a control circuit of an overcurrent protection device and a design method thereof.

The technical scheme adopted by the invention for realizing the purpose is as follows: a control circuit of an overcurrent protection device comprises a power supply module, a sampling module, a threshold analysis module and an execution protection module;

the power supply module is used for connecting an electric connector socket and converting input voltage into working voltage of the sampling module and the threshold analysis module;

the sampling module is used for connecting an electric connector socket and collecting input output signals of the electric connector socket;

the threshold analysis module is connected with the sampling module and is used for controlling the working state through the input voltage difference value;

the execution protection module is connected with the threshold analysis module, is used for connecting a release and is used for controlling the working state of the release according to the output signal of the execution analysis module.

The power module comprises a transient suppression diode, a first filter circuit, a voltage stabilizer and a second filter circuit, the transient suppression diode and the first filter circuit are connected between input voltage and a ground wire, the voltage stabilizer is connected between the input voltage and output working voltage, and the second filter circuit is connected between the output working voltage and the ground wire.

The sampling module comprises a sampling resistor and an amplifier circuit, and on-off node control is performed by controlling the current range flowing through the sampling resistor.

The threshold analysis module comprises a first comparator circuit, a second comparator circuit, a delay circuit and a third comparator circuit;

the non-inverting input ends of the first comparator circuit and the second comparator circuit are connected with the output end of the sampling module, and the inverting input end of the first comparator circuit and the second comparator circuit is connected with the output end of the power supply module after voltage division;

the non-inverting input end of the third comparator circuit is connected with the output end of the second comparator circuit, the inverting input end of the third comparator circuit is connected with the output end of the power module after voltage division, and a delay circuit is connected between the non-inverting input end and the inverting input end of the third comparator circuit.

The execution protection module comprises a first diode, a second diode and a triode;

the anode of the first diode is connected with the output end of the first comparator circuit, and the cathode of the first diode is connected with the base electrode of the triode; the anode of the second diode is connected with the output end of the third comparator circuit, and the cathode of the second diode is connected with the base electrode of the triode; and the emitting electrode of the triode is connected with the ground wire, and the collecting electrode of the triode is connected with the release.

A design method of a control circuit of an overcurrent protection device comprises the following steps:

a sampling module, a threshold analysis module and an execution protection module are sequentially arranged between the electric connector socket and the release;

the sampling module is used for collecting the input output signal of the electric connector socket; the threshold analysis module is used for controlling the working state through the input voltage difference value; the execution protection module is used for controlling the working state of the release according to the output signal of the execution analysis module.

Further comprising: and a power supply module for providing working voltage is arranged between the electric connector socket and the sampling module and between the electric connector socket and the threshold value analysis module.

The threshold analysis module comprises a first comparator circuit, a second comparator circuit, a delay circuit and a third comparator circuit;

the non-inverting input ends of the first comparator circuit and the second comparator circuit are connected with the output end of the sampling module, and the inverting input end of the first comparator circuit and the second comparator circuit is connected with the output end of the power supply module after voltage division; the non-inverting input end of the third comparator circuit is connected with the output end of the second comparator circuit, the inverting input end of the third comparator circuit is connected with the output end of the power module after voltage division, and a delay circuit is connected between the non-inverting input end and the inverting input end of the third comparator circuit.

The sampling module comprises a sampling resistor and an amplifier circuit, and on-off node control is carried out by controlling the current range flowing through the sampling resistor, specifically:

when the input current of the electric connector socket is less than 6.6A, the voltage U output by the amplifier circuit is less than the voltage of the inverting input ends of the second comparator circuit and the first comparator circuit, the comparators output low levels, the tripper does not have tripping action, and the switch is conducted;

when the input current of the electric connector socket is greater than 6.9A and less than 9.5A, the voltage U output by the amplifier circuit is greater than the voltage of the inverting input end of the second comparator circuit and less than the voltage of the inverting input end of the first comparator circuit, so that the first comparator circuit outputs a low level, the second comparator circuit outputs a high level, the delay circuit works, the capacitor starts to charge, and the third comparator outputs a high level to drive the release to disconnect the switch;

when the input current of the electric connector socket is larger than 10.5A, the voltage U output by the amplifier circuit is larger than the voltage of the inverting input end of the first comparator circuit, the first comparator circuit outputs high level, and the release is driven to disconnect the switch.

The invention has the following advantages and beneficial effects:

1. the invention can electrify the coil of the release according to the actual working current of the circuit to be protected, the product contact system and the control system drive the switch to act, and the circuit is disconnected in a delayed or instant manner, thereby protecting the rear-stage circuit.

2. The invention can be widely used in the fields of aerospace, aviation, industry, vehicles, power systems, metallurgical systems, ships and the like.

Drawings

FIG. 1 is a block diagram of the control circuit of the present invention;

FIG. 2 is a circuit schematic of a power module of the control circuit;

FIG. 3 is a schematic diagram of a sampling circuit block of the control circuit;

FIG. 4 is a schematic diagram of a threshold analysis module of the control circuit;

fig. 5 is a schematic diagram of the control circuit implementing the protection circuit module.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples.

As shown in fig. 1 to 5, the control circuit mainly includes a power module, a sampling circuit module, a threshold analysis module, and an execution protection module. The power supply module consists of a three-terminal fixed voltage regulator JW78L05, a transient suppression diode SY6053A, a capacitor and a resistor, so that a rear-stage chip is prevented from being burnt due to voltage fluctuation, and meanwhile, input voltage can be converted into 5V of working voltage required by the digital chip; the sampling circuit module mainly comprises a sampling resistor RXG12-0.01 omega/5W and a two-way operational amplifier F353 and is used for collecting input signals; the threshold analysis module consists of four comparators JF139, and the working state of the product is controlled through the input voltage difference value at the two ends of each comparator; the execution protection module consists of a triode 3DK104C and mainly has the function of preventing a product from being damaged due to misoperation.

As shown in fig. 2, the power module is constructed as follows: after the 22V-32V test voltage is input through the electric connector socket, the spike voltage existing in the circuit is subjected to anti-reverse protection through the transient suppression diode D4. After filtering the input voltage through the capacitors C5 and C6, the three-terminal regulator IC1 stabilizes the input voltage to 5V, and then the capacitors C3 and C4 filter the input voltage to provide a power supply voltage for the operational amplifier U1 and the comparator U2.

As shown in fig. 3, the sampling circuit module is configured as follows: during normal operation, the sampling resistor RQ is converted into voltage by the current in the sampling circuit, and according to the characteristics of virtual short and virtual break of the operational amplifier, the voltage at the two ends of the R2 is equal to the voltage at the two ends of the RQ, namely U_RQ＝U_R2And is I_R2＝I_R6Then U is_R2/R2＝U_{R6+ R and}and/or (R6+ R) is combined, wherein R is the parallel resistance value of R6-1, R6-2 and R6-3, and the on-off node of the overcurrent protection device can be controlled by controlling the current range flowing through the precision resistor RQ.

As shown in fig. 4, the threshold analysis module is constructed as follows: the voltage output by the sampling circuit module is used as the non-inverting input end of the comparators U2A and U2B, the voltage of the inverting input end of U2A is obtained by dividing the voltage of 5V output by the voltage stabilizer through the resistors R7, R7 ', R8 and R8', the resistance value of the resistor is adjusted according to actual requirements, and the instantaneous cut-off current value of the switch is controlled; the voltage of the inverting input end of the U2A is obtained by dividing the voltage of 5V output by the voltage stabilizer through the resistors R9, R9', R14 and R24, the resistance value of the resistor is adjusted according to actual requirements, and the current value of the switch in delayed disconnection is controlled. Comparator U2D is floating.

As shown in fig. 5, the execution protection module is configured as follows: the part mainly comprises a triode Q2, a diode D1 and a diode D2, and mainly has the advantages that the voltage at the output end of a comparator of the threshold value analysis circuit flows into a triode Q2 through one-way diodes D1 and D2, the working state of a release is controlled through the current amplification effect of the triode, and the damage of a rear-stage circuit of a product caused by misoperation is prevented.

When the product normally works, the sampling resistor RQ is converted into voltage by the current in the sampling circuit, and according to the virtual short characteristic of the operational amplifier, the voltage at two ends of the RQ is equal to the serial voltage of R2, R3 and R4; according to the characteristic of virtual break of the operational amplifier, the input current of the input end of the operational amplifier is almost 0, no current passes through R2 and R3, the current flows to Q1 through R2 and R5, the voltage at the two ends of R2 is equal to the voltage at the two ends of RQ, namely U is equal to the voltage at the two ends of RQ_RQ＝U_R2And is I_R2＝I_R6Then U is_R2/R2＝U_{R6+ R and}(R6+ Rdo), where Rdo is the parallel resistance value of R6-1, R6-2, and R6-3. In order to realize different action characteristics of products in different current ranges, two current nodes-6.7A and 10A are specially arranged and respectively correspond to output voltages of the amplifier, voltages of non-inverting input ends corresponding to comparators U2A and U2B are respectively 2.01V and 3V, and voltages of inverting input ends are respectively used as reference voltages by voltage values obtained by dividing voltages of two paths of resistorsThe reference voltage of U2A is (R8+ R8 ')/(R8 + R8 ' + R24+ R7 ')/5V — 3V; the reference voltage of U2B is (R9+ R9 ')/(R9 + R9' + R24) × 5V ═ 2.06V; the working conditions were as follows:

a) when the current is less than 6.6A, the voltage U output by the amplifying circuit is less than the reference voltage of the comparators U2B and U2A, the comparators output low level, and the circuit plays a role of switching;

b) when the current is greater than 6.9A and less than 9.5A, the voltage U output by the amplifying circuit is greater than the reference voltage of the comparator U2B and less than the reference voltage of U2A, so that the comparator U2A outputs a low level, the U2B outputs a high level, the capacitor C1 starts to charge, and after 4 s-5 s, when the voltage at two ends of the C1 is obtained, the comparator U2C outputs a high level to drive the release to open the switch;

c) when the current is larger than 10.5A, the voltage U output by the amplifying circuit is larger than the reference voltage of the comparator U2A, the comparator U2A outputs high level, and the tripper is driven to immediately turn off the switch, wherein the time is less than 1 s.

Through the calculation, the overcurrent protection device designed by applying the control circuit principle can realize the following functions:

a) when the current is less than 6.6A, the electrified equipment works normally;

b) cutting off the surge of 6.9-9.5A, and delaying for 4-5 seconds;

c) surges of more than 10.5A are switched off in less than 1 second.

At present, the applicant adopts the circuit principle to complete the production work of 3 overcurrent protection devices, all pass the performance test, and the test result is as follows (any voltage point completes all current point test work):

the voltage test points are 22V, 24V, 25.5V, 30V and 32V;

the current test points are 3.2A, 6.6A, 6.9A, 8A, 9.5A, 10.5A, 11A.

a) Under the conditions of 3.2A and 6.6A, a product switch is not disconnected after being closed and electrified (the test time is 1 min);

b) under the conditions of 6.9A, 8A and 9.5A, the product switch is switched off after being powered on for 4-5 seconds;

c) the product switch is closed under the conditions of 10.5A and 11A and is opened within 1 second.