CN115377937B

CN115377937B - Electronic fuse structure, power supply device comprising same and working method of electronic fuse structure

Info

Publication number: CN115377937B
Application number: CN202211299296.2A
Authority: CN
Inventors: 王鑫; 郝世强; 邵庆辉; 李宏阳; 齐明志
Original assignee: Foote Intelligent Hangzhou Information Technology Co ltd; Zhejiang Fute Technology Co ltd
Current assignee: Foote Intelligent Hangzhou Information Technology Co ltd; Zhejiang Fute Technology Co ltd
Priority date: 2022-10-24
Filing date: 2022-10-24
Publication date: 2023-03-24
Anticipated expiration: 2042-10-24
Also published as: CN115377937A

Abstract

The invention provides an electronic fuse structure, a power supply device comprising the same and a working method of the electronic fuse structure, and relates to the field of power supplies, wherein the electronic fuse structure comprises a switch tube, a first end of the switch tube is used for being connected with a power supply, a second end of the switch tube is used for being connected with a first end of a capacitive load, and a second end of the capacitive load is grounded; the first end of the first resistance unit is connected with the control end of the switch tube; the driving signal generating unit comprises a first end and a second end, the first end is connected with the second end of the first resistor unit, the first end of the driving signal generating unit is used for outputting driving signals, the driving signals comprise a first level and a second level higher than the first level, reference voltage points of the first level and the second level are the second end of the driving signal generating unit, and the second end of the driving signal generating unit is connected with the second end of the switching tube; and the first end of the capacitor unit is connected with the control end of the switch tube, the second end of the capacitor unit is grounded, and when the electronic fuse is initially switched on, the capacitor unit charges the capacitive load at a constant current.

Description

Electronic fuse structure, power supply device comprising same and working method of electronic fuse structure

Technical Field

The invention relates to the field of power supplies, in particular to an electronic fuse structure, a power supply device comprising the electronic fuse structure and a working method of the electronic fuse structure.

Background

The fuse is generally used between a power supply and a load, so that when the load current exceeds a rated design, the load is disconnected by fusing the fuse, and load equipment is prevented from being damaged and other equipment is protected from working normally. However, the fuse has the defects that the fuse is irreversible, needs to be replaced, and has high maintenance cost.

The scheme of an electronic fuse (use) is adopted, namely, the fuse is replaced by a switch tube, so that overcurrent protection can be realized, and the overcurrent protector is not damaged and can be used repeatedly; and the on-off can be actively controlled, so that intelligent control is realized. The advantages of the method are clear and are the current mainstream trend.

However, a voltage stabilizing capacitor is usually present at the input end of a capacitive load, such as a low-voltage load of an automobile, and can reach the mF level, namely the low-voltage load is presented as the capacitive load. If the current limiting measure is not applied, the capacitor at the end of the capacitive load may cause a large surge current, which may reach a level of 100A or 1000A, at the moment when the electronic fuse is turned on to charge the capacitive load, which may damage the capacitive load or other devices.

Disclosure of Invention

The application provides an electronic fuse structure, includes: an electronic fuse structure, comprising: the first end of the switch tube is used for connecting a power supply, the second end of the switch tube is used for connecting the first end of a capacitive load, and the second end of the capacitive load is grounded; the first end of the first resistance unit is connected with the control end of the switch tube; the driving signal generating unit comprises a first end and a second end, the first end is connected with the second end of the first resistor unit, the first end of the driving signal generating unit is used for outputting driving signals, the driving signals comprise a first level and a second level higher than the first level, reference voltage points of the first level and the second level are the second end of the driving signal generating unit, and the second end of the driving signal generating unit is connected with the second end of the switching tube; and the first end of the capacitor unit is connected with the control end of the switch tube, and the second end of the capacitor unit is grounded.

Furthermore, the capacitance of the capacitor unit is much smaller than that of the capacitive load.

Furthermore, the circuit further comprises a resistor-diode series structure, wherein the resistor-diode series structure comprises a second resistor unit and a first diode which are connected in series, the resistor-diode series structure is connected in parallel at two ends of the first resistor unit, the anode of the first diode is connected with the first end of the first resistor unit, and the cathode of the first diode is connected with the second end of the first resistor unit.

Furthermore, the switch tube further comprises a third resistance unit, and the third resistance unit is connected between the control end of the switch tube and the capacitance unit.

Furthermore, the power supply further comprises a triode, a fourth resistor unit and a second diode, wherein an emitting electrode of the triode is connected with the first end of the capacitor unit and the cathode of the second diode, a collector electrode of the triode is grounded through the fourth resistor unit, a base electrode of the triode is connected with the first end of the first resistor unit through a fifth resistor unit, and an anode of the second diode is connected with the first end of the first resistor unit.

Furthermore, the circuit also comprises a triode, a fourth resistance unit and a second diode, wherein an emitting electrode of the triode is connected with a common node of a cathode of the third resistance unit and a cathode of the second diode, a collector electrode of the triode is grounded through the fourth resistance unit, a base electrode of the triode is connected with the first end of the first resistance unit through a fifth resistance unit, and an anode of the second diode is connected with the first end of the first resistance unit.

The present application also provides a power supply device, including: the power supply is used for providing a direct current voltage; a capacitive load; the electronic fuse structure is connected between the power supply and the capacitive load.

The application also provides a working method based on the power supply device, which comprises the following steps: in the initial stage, a first end of the driving signal generating unit outputs a driving signal of a first level, the switching tube is in a turn-off state, the voltage between the control end and a second end of the switching tube, the voltage of the capacitor unit and the voltage of the capacitive load are all zero, and the power supply supplies power normally; starting a first stage, when the first stage is started, the driving signal output by the first end of the driving signal generating unit is stepped from a first level to a second level, the capacitor unit and the control end-second end of the switching tube are charged, so that the voltage of the capacitor unit and the voltage between the control end and the second end of the switching tube are gradually increased to charge the capacitor unit and the control end-second end of the switching tube, the voltage of the capacitor unit and the voltage between the control end and the second end of the switching tube are gradually increased, but the voltage between the control end and the second end of the switching tube is smaller than the conduction threshold value of the switching tube, and the switching tube is in a turn-off state until the voltage between the control end and the second end of the switching tube is increased to the conduction threshold value of the switching tube; starting a second stage, wherein the switching tube is conducted and works in a saturation region, the voltage between the control end and the second end of the switching tube is continuously increased, the power supply charges the capacitive load through the conducted switching tube, the voltage on the capacitive load is gradually increased, the current flowing through the capacitive load is gradually increased until the voltage between the control end and the second end of the switching tube is increased to a first driving voltage, and the current flowing through the capacitive load is increased to a first output current; in the third stage of starting, the voltage between the control end and the second end of the switch tube is kept at the first driving voltage, the switch tube is conducted and works in a saturation region, the power supply charges the capacitive load through the conducted switch tube, the voltage on the capacitive load is gradually increased but is smaller than the voltage provided by the power supply, and the current flowing through the capacitive load is kept at the first output current; starting a fourth stage, continuously charging the capacitive load, gradually increasing the voltage to the direct-current voltage, gradually reducing the current flowing through the capacitive load to zero, and continuously increasing the voltage between the control end and the second end of the switch tube; starting a fifth stage, and continuously increasing the voltage between the control end and the second end of the switching tube until the voltage is equal to the second level of the driving signal; and in the normal working stage, the voltage between the control end and the second end of the switch tube keeps a second level, and the power supply supplies power to the capacitive load through the switched-on switch tube.

Furthermore, in the first starting stage, the voltage between the control end and the second end of the switching tube is approximately equal to the voltage of the capacitor unit, and the voltage between the control end and the second end of the switching tube and the voltage rising speed of the capacitor unit are gradually reduced; in the second starting stage, the voltage rising speed between the control end and the second end of the switch tube is gradually reduced; in a third starting stage, the voltage between the control end and the second end of the switching tube maintains a stable value; in a fourth starting stage, the voltage rising speed between the control end and the second end of the switch tube is gradually reduced; in the fifth starting stage, the voltage rising speed between the control end and the second end of the switch tube is gradually reduced until the voltage rising speed is zero.

Furthermore, in the second stage of starting, the current flowing through the capacitive load is approximately equal to (vgs-vgs (th)). Times.gm, where vgs is the voltage between the control end and the second end of the switching tube, vgs (th) is the conduction threshold of the switching tube, and gm is the transconductance of the switching tube; in the third stage, the current flowing through the capacitive load is equal to Cout ((V2-vgs 1)/(R1 × C1)), where Cout is the capacitance of the capacitive load, V2 is the voltage of the second level of the driving signal, R1 is the resistance of the first resistor unit, and C1 is the capacitance of the capacitor unit.

Furthermore, when the electronic fuse is required to be turned off, the driving signal output by the first end of the driving signal generating unit is switched from the second level to the first level, the first diode is turned on, and the voltage between the control end and the second end of the switching tube is discharged through the resistor-diode series structure and the driving signal generating unit until the switching tube is turned off.

Further, when the electronic fuse is required to be opened, the voltage on the capacitor unit is discharged through the resistor-diode series structure, the driving signal generating unit and the capacitive load.

Furthermore, when the electronic fuse is required to be disconnected, the voltage on the capacitor unit is discharged through the third resistor unit, the resistor-diode series structure, the driving signal generating unit and the capacitive load.

Furthermore, when the driving signal output by the first end of the driving signal generating unit is at the first level, the triode is turned on, and the voltage on the capacitor unit is discharged through the triode and the fourth resistor unit.

Drawings

Fig. 1 is a schematic structural diagram of an electronic fuse according to a first embodiment of the invention.

Fig. 2 is an operational waveform schematic of the electronic fuse structure shown in fig. 1.

Fig. 3 is a schematic diagram of a charging path of the electronic fuse structure shown in fig. 1 at a first stage of starting.

FIG. 4 is a schematic diagram of a charging path of the electronic fuse structure shown in FIG. 1 during a second phase.

Fig. 5 is a schematic diagram of an equivalent model of a charging path of the electronic fuse structure shown in fig. 1 at a third stage of starting.

Fig. 6 is a schematic structural diagram of an electronic fuse according to a second embodiment of the present invention.

Fig. 7 is a schematic structural diagram of an electronic fuse according to a third embodiment of the invention.

Fig. 8 is a schematic structural diagram of an electronic fuse according to a fourth embodiment of the invention.

Detailed Description

The technical solutions in the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

In an embodiment of the present invention, an electronic fuse structure is provided. Specifically, referring to fig. 1, an electronic fuse structure 100 according to a first embodiment of the present invention is applicable to a power supply device 10, where the electronic fuse structure 100 includes:

a first end of the switching tube Q1 is used for connecting a power supply Vin, a second end of the switching tube Q1 is used for connecting a first end of a capacitive load Cout, and a second end of the capacitive load Cout is grounded;

the first end of the first resistance unit R1 is connected with the control end of the switching tube Q1;

the driving signal generating unit 110 includes a first end and a second end, the first end is connected to the second end of the first resistor unit R1, the first end of the driving signal generating unit 110 is configured to output a driving signal Vdriver, the driving signal Vdriver includes a first level V1 and a second level V2 higher than the first level V1, reference voltage points of the first level V1 and the second level V2 are the second end of the driving signal generating unit, and the second end of the driving signal generating unit 110 is connected to the second end of the switching tube Q1;

and a first end of the capacitor unit C1 is connected with the control end of the switch tube Q1, and a second end of the capacitor unit C1 is grounded.

The capacitance of the capacitor unit C1 is usually between 0.1uf and 1uf, and the capacitance of the capacitive load Cout can reach mF level, that is, the capacitance of the capacitor unit C1 is much smaller than the capacitance of the capacitive load Cout. For example, the capacitance of the capacitive load Cout is more than 100 times or more than 1000 times the capacitance of the capacitor unit C1.

The capacitive load Cout may be a low-voltage load in the new energy vehicle, and may also be a capacitive load in other application scenarios.

Taking a new energy automobile as an example, the low-voltage load in the new energy automobile is various and the working condition is complex. In some schemes, the vehicle-mounted load is connected with the power supply through a fuse, and when the load current exceeds the rated design, the load is disconnected through the fuse fusing, so that the load equipment is prevented from being damaged, and other equipment is protected from working normally. However, the fuse has the defects that the fuse is irreversible, needs to be replaced, and has high maintenance cost.

However, since the input terminal of the low-voltage load of the automobile usually has a voltage stabilizing capacitor, the input terminal can reach the mF level, namely, the low-voltage load presents a capacitive load. If the current limiting measure is not applied, the capacitor at the end of the capacitive load may cause a large surge current, which may reach a level of 100A or 1000A, at the moment when the electronic fuse is turned on to charge the capacitive load, which may damage the capacitive load or other devices.

Based on this, there is a need for an electronic fuse structure, which, on the basis of having the advantages of an electronic fuse (efuse), can also suppress a large inrush current when the electronic fuse is turned on to charge a capacitive load, thereby avoiding damage to the capacitive load or other devices.

The driving signal Vdriver output by the first end of the driving signal generating unit 110 in the electronic fuse structure of fig. 1 includes a first level V1 and a second level V2 higher than the first level V1, and may refer to an operation waveform diagram of the electronic fuse structure shown in fig. 1 shown in fig. 2, where the driving signal Vdriver is only shown to step from the first level V1 to the second level V2 at time t0, and then is maintained at the second level V2. In practical use, the driving signal Vdriver may also be maintained at the first level V1; or from the second level V2 to the first level V1 and thereafter remains at the first level V1.

The reference voltage points of the first level V1 and the second level V2 are the second ends of the driving signal generating units. Specifically, the first level V1 is usually about 0V, and the second level V2 is usually 12V. In practical applications, the first level V1 and the second level V2 may also be other voltage values, as long as the first level V1 drives the switch tube to turn off the switch tube, and the second level V2 drives the switch tube to turn on the switch tube.

The application also provides a power supply device. Specifically, referring to fig. 1, the power supply device 10 includes:

a power supply Vin for providing a dc voltage Vdc;

a capacitive load Cout;

in the electronic fuse structure 100 shown in fig. 1, the electronic fuse structure 100 is connected between the power supply Vin and the capacitive load Cout, and is used for intelligently controlling connection or disconnection between the power supply Vin and the capacitive load Cout, and charging the capacitive load Cout at a constant current at the initial connection, so as to suppress a large surge current on the capacitive load Cout and avoid damage to the capacitive load or other devices.

The power supply Vin is a dc source for continuous power supply in the power supply device. Such as a 12V, 24V or 48V dc source or battery as found in electric vehicles.

The resistance of the first resistance unit R1 is large, such as kilo ohms.

Referring to fig. 1 and fig. 2, in an initial stage, the first end of the driving signal generating unit 110 outputs the driving signal Vdriver with a first level V1 (e.g. 0V), the switching tube Q1 is in an off state, and the voltage between the control end and the second end of the switching tube Q1, the voltage of the capacitor unit C1, and the voltage of the capacitive load Cout are all zero, at this time, the power supply Vin normally supplies power, but the capacitive load is not charged.

Referring to the schematic diagram of the charging path during the first stage of starting shown in fig. 3, and referring to fig. 2, at the first stage of starting, that is, at the time point from t0 to t1, at the time point t0, the driving signal Vdriver output by the first end of the driving signal generating unit 110 is stepped from the first level V1 (e.g., 0V) to the second level V2 (e.g., 12V), that is, the starting stage starts, the capacitor unit C1 and the control end-second end of the switching tube Q1 are charged, so that the voltage of the capacitor unit C1 and the voltage between the control end and the second end of the switching tube Q1 gradually increase, but the voltage vgs between the control end and the second end of the switching tube Q1 is smaller than the turn-on threshold vgs (th) of the switching tube, and the switching tube Q1 is in the turn-off state until the voltage vgs between the control end and the second end of the switching tube Q1 increases to the turn-on threshold vgs (th) of the switching tube (time point t 1).

As shown in fig. 3, in the first stage of the start-up, after the driving signal Vdriver is stepped from the first level V1 (e.g. 0V) to the second level V2 (e.g. 12V), the driving signal generating unit 110 charges the control end-the second end of the switching tube Q1 through the first resistor unit R1, the charging current is igs, meanwhile, the capacitive load Cout and the driving signal generating unit 110 charge the capacitor unit C1 through the first resistor unit R1, the charging current is ic1, and then the voltage vgs of the control end and the second end of the switching tube Q1 and the voltage Vc1 on the capacitor unit C1 gradually increase.

During this period, the switching tube Q1 is in an off state, and the voltage Vout on the capacitive load Cout and the current Iout flowing through the capacitive load Cout are both zero. The voltage vgs between the control end and the second end of the switch tube is approximately equal to the voltage Vc1 of the capacitor unit, and the charging current ic1 gradually decreases as the voltage Vc1 on the capacitor unit C1 gradually increases, so the rising speed of the voltage vgs between the control end and the second end of the switch tube and the voltage Vc1 of the capacitor unit gradually decreases.

Referring to the schematic diagram of the charging path during the second stage of starting shown in fig. 4, and referring to fig. 2, at the second stage of starting, that is, at the time point t1 to t2, since at the time point t1, the voltage vgs between the control end and the second end of the switching tube Q1 is increased to the conduction threshold vgs (th) of the switching tube, and is continuously increased, the switching tube Q1 is conducted and operates in a saturation region, the power supply Vin charges the capacitive load Cout through the conducted switching tube Q1, the current flowing through the switching tube Q1 is iQ1, the voltage Vout on the capacitive load Cout is gradually increased, and the current Iout flowing through the capacitive load Cout is gradually increased until the voltage vgs between the control end and the second end of the switching tube Q1 is increased to the first driving voltage vgs1, and the current flowing through the capacitive load, that is, is increased to the first output current Iout1 (at the time point t 2).

As shown in fig. 4, in the second stage of starting, the capacitive load Cout and the driving signal generating unit 110 continue to charge the capacitor unit C1 through the first resistor unit R1, and the charging current is ic1, the voltage Vc1 on the capacitor unit C1 continues to gradually increase, and the charging current ic1 gradually decreases, that is, the speed of increasing the voltage Vc1 on the capacitor unit C1 is reduced, but the speed of increasing the voltage Vc1 on the capacitor unit C1 is greater than the speed of increasing the voltage Vout on the capacitive load Cout, and the voltage vgs = Vc1-Vout between the control end and the second end of the switching tube Q1, so the voltage vgs between the control end and the second end of the switching tube Q1 still continues to increase. As the rising speed of the voltage Vc1 on the capacitor unit C1 is slowed down, the rising speed of the voltage Vout on the capacitive load Cout is increased, the voltage vgs between the control end and the second end of the switch tube Q1 is continuously increased, and the speed is further slowed down until the voltage vgs between the control end and the second end of the switch tube Q1 is increased to the first driving voltage vgs1 at time t2, and then is not increased any more.

In the second stage of starting, iQ1= iout + ic1, where iout is much greater than ic1, and then iQ1 is approximately equal to iout, and then the current iout flowing through the capacitive load is approximately equal to (vgs-vgs (th)). Gm, where vgs is the voltage between the control terminal and the second terminal of the switching tube, vgs (th) is the turn-on threshold of the switching tube, and gm is the transconductance of the switching tube. Therefore, in the second phase of starting, the current iout flowing through the capacitive load is controlled by the voltage vgs between the control end and the second end of the switch tube, and increases with the increase of the voltage vgs until the time t 2. While ic1 gradually decreases during this period until it is no longer decreasing at time t 2.

With reference to fig. 4 and fig. 2, in the third stage of starting, that is, at the time point t2 to t3, the voltage vgs between the control end and the second end of the switching tube Q1 is maintained at the first driving voltage vgs1, the switching tube Q1 is turned on and operates in the saturation region, the power supply Vin charges the capacitive load Cout through the turned-on switching tube Q1, the voltage Vout on the capacitive load Cout is gradually increased but is smaller than the voltage Vdc provided by the power supply Vin, and the current iout flowing through the capacitive load Cout is maintained at the first output current iout1.

Specifically, in the third stage of starting, the capacitive load Cout and the driving signal generating unit 110 continue to charge the capacitor unit C1 through the first resistor unit R1, and the voltage Vout on the capacitive load Cout rises at the same speed as the voltage Vc1 on the capacitor unit C1, so that the voltage vgs between the control end and the second end of the switching tube Q1 is maintained at the first driving voltage vgs1.

As can be seen from the charging path in fig. 4, the current iR1= (V2-vgs 1)/R1 flowing through the first resistor unit R1, and ic1= (V2-vgs 1)/R1 can be obtained because iR1= ic 1.iout = Cout × dvut/dt, ic1= C1 × dVc 1/dt, and since dVc1= dvut, iout = ic1 × Cout/C1. The capacitive load driving circuit is obtained by ic1= (V2-vgs 1)/R1 and iout = ic1 × Cout/C1, iout = Cout ((V2-vgs 1)/(R1 × C1)), where Cout is a capacitance value of the capacitive load, V2 is a voltage value of the second level of the driving signal, R1 is a resistance value of the first resistor unit, and C1 is a capacitance value of the capacitor unit. As can be seen from the expression iout = Cout ((V2-vgs 1)/(R1 × C1)), in the third start-up phase, the current iout flowing through the capacitive load Cout is affected by the difference between V2 and vgs1, the resistance of the first resistor unit R1, and the capacitance of the capacitor unit C1. The current iout flowing through the capacitive load Cout can be controlled by selecting different resistance values of the first resistor unit and capacitance values of the capacitor unit, that is, the current flowing through the capacitive load Cout can be suppressed.

Please refer to fig. 5, which shows a schematic diagram of an equivalent model of the charging path shown in fig. 4 at the third stage of starting, wherein Vdriver, 1/R1, ^ C1, f (vgs) and ^ C/Cout correspond to equivalent mathematical models of the driving signal generating unit 110, the first resistor unit R1, the capacitor unit C1, the switching tube Q1 and the capacitive load Cout, respectively. As can be seen from fig. 5, in the third stage of the start-up, from the first negative feedback path 510, when vgs is increased, iR1 is decreased, vc1 is decreased, and vgs is decreased; similarly, from the second negative feedback path 520, when vgs increases, iout increases, and Vout increases, vgs decreases. Continuing with fig. 5, at the third stage of starting, it can be seen from the first negative feedback path 510 that when Vgs is decreased, iR1 is increased, vc1 is increased, and Vgs is increased; similarly, from the second negative feedback path 520, when vgs decreases, iout decreases, and Vout decreases, vgs increases. Therefore, the voltage vgs between the control terminal and the second terminal of the switching tube Q1 is dynamically stabilized at the first driving voltage vgs1 in the third stage of starting. According to the principle of voltage-controlled current source, the switching tube Q1 works in the saturation region and charges the capacitive load Cout with a constant current. With reference to fig. 4 and fig. 2, in the fourth phase of starting, that is, at the time point t3 to t4, the capacitive load Cout continues to be charged, the voltage Vout gradually increases to the voltage Vdc provided by the power supply Vin (that is, at the time point t 4), the current iout flowing through the capacitive load Cout gradually decreases to zero, and the voltage vgs between the control end and the second end of the switching tube Q1 continues to increase.

As shown in fig. 4, since the capacitive load Cout and the driving signal generating unit 110 continue to charge the capacitor unit C1 through the first resistor unit R1, and the voltage Vc1 across the capacitor unit C1 continues to increase, the voltage vgs between the control end and the second end of the switching tube Q1 also continues to increase, but the increasing speed gradually decreases, that is, the ic1 gradually decreases during this period.

With continued reference to fig. 4 and fig. 2, during the fifth phase of starting, i.e. from time t4 to time t5, the voltage vgs between the control terminal and the second terminal of the switching tube Q1 continues to increase until it is equal to the second level V2 of the driving signal (i.e. time t 5).

As shown in fig. 4, since the capacitive load Cout and the driving signal generating unit 110 continue to charge the capacitor unit C1 through the first resistor unit R1, and the voltage Vc1 on the capacitor unit C1 continues to increase, the voltage vgs between the control end and the second end of the switching tube Q1 also continues to increase, but ic1 gradually decreases, and the increasing speed of the voltage vgs gradually slows down to zero, that is, at time t 5. At this time, the voltage Vc1 on the capacitor C1 is the sum of the voltage of the second level V2 of the driving signal Vdriver and the voltage (equal to Vdc in this case) on the capacitive load Cout.

From time t0 to time t5, the whole pre-charging stage is called the starting stage of the capacitive load Cout, or the switching-on process of the electronic fuse switch tube. As can be seen from the above analysis, in this process, the maximum value of the current iout flowing through the capacitive load is clamped to Cout ((V2-vgs 1)/(R1 × C1)), and is controlled by the selected resistance values of the switching tube Q1 and the first resistance unit R1 and the capacitance value of the capacitance unit C1, so that the capacitive load is charged with a constant current at the initial time when the electronic fuse switching tube is turned on to charge the capacitive load, thereby suppressing a large surge current on the capacitive load and avoiding damage to the capacitive load or other devices. Because the on-off of the switch tube Q1 is controllable, the switch tube Q also has the advantages of being capable of actively controlling on-off of a conventional electronic fuse (efuse) and achieving intelligent control.

As described above, the capacitance value of the capacitive load Cout is more than 100 times, or more than 1000 times, the resistance value R1 of the first resistor unit is usually several kilo ohms, V2 is usually 12V, and vgs1 of the switching tube Q1 is usually several volts, for example, 3V, and then, as can be seen from Cout ((V2-vgs 1)/(R1 + C1)), in the third stage of starting, the current iout flowing through the capacitive load Cout can be designed to be a preset value, for example, several amperes, by parameters.

After the time t5, the power supply enters a normal working stage, the voltage vgs between the control end and the second end of the switching tube Q1 maintains the second level V2, and the power supply Vin supplies power to the capacitive load Cout through the switched-on switching tube Q1.

Referring to fig. 6, a schematic diagram of an electronic fuse structure according to a second embodiment of the present invention further includes a resistor-diode series structure 120 on the basis of the electronic fuse structure according to the first embodiment, the resistor-diode series structure 120 includes a second resistor unit R2 and a first diode D1 connected in series, the resistor-diode series structure 120 is connected in parallel to two ends of the first resistor unit R1, wherein an anode of the first diode D1 is connected to a first end of the first resistor unit R1, and a cathode of the first diode D1 is connected to a second end of the first resistor unit R1.

Fig. 6 illustrates an example in which the anode of the first diode D1 is connected to the first end of the first resistance unit R1 through the second resistance unit R2. Of course, the anode of the first diode D1 may be directly connected to the first end of the first resistor unit R1, and the cathode of the first diode D1 may be connected to the second end of the first resistor unit R1 through the second resistor unit R2.

When the electronic fuse is required to be disconnected, if abnormal conditions such as overcurrent occur in the load, the switching tube Q1 connected between the power supply Vin and the capacitive load Cout needs to be controlled to be turned off. Based on this, referring to fig. 6, when an abnormal operating condition is detected, the driving signal Vdriver output by the first end of the driving signal generating unit 110 is switched from the second level V2 to the first level V1, if 0V, the first diode D1 is turned on, and the voltage vgs between the control end and the second end of the switching tube Q1 is discharged through the resistor-diode series structure 120 and the driving signal generating unit 110 until the switching tube Q1 is turned off. Usually, the resistance of the second resistor unit R2 is very small, for example, several ohms, so that the capacitor unit C1 can be rapidly discharged in a short time, and the voltage vgs between the control terminal and the second terminal of the switching tube Q1 is reduced to be below the turn-on threshold vgs (th), thereby achieving the function of rapidly turning off the switching tube Q1 and performing fault protection.

Specifically, when the electronic fuse is required to be opened, the voltage vgs from the control terminal to the second terminal of the switching tube Q1 is discharged through the resistor-diode series structure 120 and the driving signal generating unit 110.

For the second embodiment shown in fig. 6, during the failure, the voltage vgs between the control terminal and the second terminal of the switch Q1 needs to be reduced to be lower than the turn-on threshold vgs (th), so the voltage Vc1 on the capacitor C1 needs to be pulled down to be approximately equal to the voltage Vout on the capacitive load Cout. According to the above analysis, at time t5, the voltage Vc1 on the capacitor C1 is the sum of the voltage of the second level V2 of the driving signal Vdriver and the voltage of the capacitive load Cout, and therefore, the voltage Vc1 on the capacitor C1 needs to be pulled down by the voltage value of the second level V2 of the driving signal Vdriver.

Specifically, when the electronic fuse is required to be turned off, the voltage Vc1 of the capacitor unit C1 is discharged through the resistor-diode series structure 120, the driving signal generating unit 110 and the capacitive load Cout.

Referring to fig. 7, a schematic diagram of an electronic fuse structure according to a third embodiment of the present invention further includes a third resistor unit R3 based on the second embodiment, wherein the third resistor unit R3 is connected between the control end of the switch Q1 and the capacitor unit C1. When the electronic fuse is required to be disconnected, the voltage vgs between the control end and the second end of the switching tube Q1 also needs to be reduced to be lower than the turn-on threshold value vgs (th), so that the voltage Vc1 on the capacitor unit C1 needs to be pulled down, and at this time, because a certain voltage drop exists on the third resistor unit R3, the voltage value that the voltage Vc1 on the capacitor unit C1 needs to be pulled down can be reduced, that is, the voltage value that the voltage Vc1 on the capacitor unit C1 needs to be pulled down is smaller than the voltage value of the second level V2 of the driving signal Vdriver, so that the disconnection speed of the switching tube Q1 can be increased, and a faster fault protection function can be realized.

Specifically, when the electronic fuse is required to be turned off, the voltage Vc1 on the capacitor unit C1 is discharged through the third resistor unit R3, the resistor-diode series structure 120, the driving signal generating unit 110 and the capacitive load Cout.

Please refer to fig. 8, which is a schematic diagram of a structure including an electronic fuse according to a fourth embodiment of the present invention, and further includes a transistor S1, a fourth resistance unit R4, and a second diode D2 based on the first embodiment, wherein an emitter e of the transistor S1 is connected to a first end of the capacitor unit C1 and a cathode of the second diode D2, a collector C of the transistor S1 is grounded through the fourth resistance unit R4, a base b of the transistor C1 is connected to the first end of the first resistance unit R1 through a fifth resistance unit R5, and an anode of the second diode D2 is connected to the first end of the first resistance unit R1.

Of course, the electronic fuse structure of the second embodiment may further include the transistor S1, the fourth resistor unit R4, the fifth resistor unit R5, and the second diode D2, which have the same connection relationship, and are not described herein again.

Of course, the electronic fuse structure of the third embodiment may further include the transistor S1, the fourth resistor unit R4, the fifth resistor unit R5, and the second diode D2. At this time, the emitter e of the triode S1 is connected to the common node of the third resistor unit R3 and the cathode of the second diode D2, the collector c of the triode S1 is grounded through the fourth resistor unit R4, the base b of the triode S1 is connected to the first end of the first resistor unit R1 through the fifth resistor unit R4, and the anode of the second diode D2 is connected to the first end of the first resistor unit R1.

Before the capacitive load Cout is started, i.e., in the initial stage, it is desirable that the voltage of the capacitor unit C1 is zero, and then the capacitor unit C1 is charged in the subsequent starting process, so that the starting process is normally performed, i.e., the starting process is performed. As described above, at the end of the start-up process, i.e. at time t5, the voltage Vc1 across the capacitor C1 is the sum of the voltage of the second level V2 of the driving signal Vdriver and the voltage across the capacitive load Cout (which is equal to Vdc in this case). Therefore, when the capacitive load Cout does not need to be driven, that is, when the driving signal Vdriver output from the first terminal of the driving signal generating unit 110 is at the first level V1 (e.g., 0V), it is desirable that the capacitor unit C1 is discharged to zero.

As shown in fig. 8, when the driving signal Vdriver output by the first end of the driving signal generating unit 110 is at the first level V1 (e.g. 0V), the voltage across the capacitor unit C1 is maintained due to the fact that the second diode D2 cannot be conducted in the reverse direction, and the transistor S1 is conducted, and the voltage VC1 across the capacitor unit C1 is discharged through the transistor S1 and the fourth resistor unit R4 until the voltage is discharged to zero. The first stage to the fifth stage of the start-up can be performed next time the capacitive load Cout needs to be driven. Therefore, the electronic fuse is simple in structure and high in reliability.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An electronic fuse structure, comprising:

the first end of the switch tube is used for connecting a power supply, the second end of the switch tube is used for connecting the first end of a capacitive load, and the second end of the capacitive load is grounded;

the first end of the first resistance unit is connected with the control end of the switch tube;

the driving signal generating unit comprises a first end and a second end, the first end is connected with the second end of the first resistor unit, the first end of the driving signal generating unit is used for outputting a driving signal, and the second end of the driving signal generating unit is connected with the second end of the switching tube;

and the first end of the capacitor unit is connected with the control end of the switch tube, and the second end of the capacitor unit is grounded.

2. The electrical fuse structure of claim 1, wherein the capacitance of the capacitor unit is substantially less than the capacitance of the capacitive load.

3. The electronic fuse structure according to claim 1, further comprising a resistor-diode series structure comprising a second resistor unit and a first diode connected in series, the resistor-diode series structure being connected in parallel across the first resistor unit.

4. The electronic fuse structure of claim 3, further comprising a third resistance unit connected between the control terminal of the switching tube and the capacitance unit.

5. The electronic fuse structure according to claim 1, further comprising a triode, a fourth resistor unit and a second diode, wherein an emitter of the triode is connected to the first end of the capacitor unit and a cathode of the second diode, a collector of the triode is grounded through the fourth resistor unit, a base of the triode is connected to the first end of the first resistor unit through a fifth resistor unit, and an anode of the second diode is connected to the first end of the first resistor unit.

6. The electronic fuse structure of claim 3, further comprising a triode, a fourth resistor unit, and a second diode, wherein an emitter of the triode is connected to the first terminal of the capacitor unit and a cathode of the second diode, a collector of the triode is grounded through the fourth resistor unit, a base of the triode is connected to the first terminal of the first resistor unit through a fifth resistor unit, and an anode of the second diode is connected to the first terminal of the first resistor unit.

7. The electronic fuse structure according to claim 4, further comprising a triode, a fourth resistor unit and a second diode, wherein an emitter of the triode is connected to a common node of the third resistor unit and a cathode of the second diode, a collector of the triode is grounded through the fourth resistor unit, a base of the triode is connected to the first end of the first resistor unit through a fifth resistor unit, and an anode of the second diode is connected to the first end of the first resistor unit.

8. The electrical fuse structure of claim 1, wherein the driving signal comprises a first level and a second level higher than the first level, wherein a reference voltage point of the first level and the second level is the second end of the driving signal generating unit.

9. A power supply device, comprising:

the power supply is used for providing a direct current voltage;

a capacitive load;

the electrical fuse structure of any one of claims 1-8, connected between said power supply and said capacitive load.

10. An operation method of the power supply device according to claim 9, comprising:

in the initial stage, a first end of the driving signal generating unit outputs a driving signal of a first level, the switching tube is in a turn-off state, the voltage between the control end and a second end of the switching tube, the voltage of the capacitor unit and the voltage of the capacitive load are all zero, and the power supply supplies power normally;

starting a first stage, when the first stage is started, the driving signal output by the first end of the driving signal generating unit is stepped from a first level to a second level, the capacitor unit and the control end-second end of the switching tube are charged, so that the voltage of the capacitor unit and the voltage between the control end and the second end of the switching tube are gradually increased, but the voltage between the control end and the second end of the switching tube is smaller than the conduction threshold value of the switching tube, and the switching tube is in a turn-off state until the voltage between the control end and the second end of the switching tube is increased to the conduction threshold value of the switching tube;

starting a second stage, wherein the switching tube is conducted and works in a saturation region, the voltage between the control end and the second end of the switching tube is continuously increased, the power supply charges the capacitive load through the conducted switching tube, the voltage on the capacitive load is gradually increased, the current flowing through the capacitive load is gradually increased until the voltage between the control end and the second end of the switching tube is increased to a first driving voltage, and the current flowing through the capacitive load is increased to a first output current;

in the third stage of starting, the voltage between the control end and the second end of the switch tube is kept at the first driving voltage, the switch tube is conducted and works in a saturation region, the power supply charges the capacitive load through the conducted switch tube, the voltage on the capacitive load is gradually increased but is smaller than the voltage provided by the power supply, and the current flowing through the capacitive load is kept at the first output current;

starting a fourth stage, continuously charging the capacitive load, gradually increasing the voltage to the direct-current voltage, gradually reducing the current flowing through the capacitive load to zero, and continuously increasing the voltage between the control end and the second end of the switch tube;

starting a fifth stage, and continuously increasing the voltage between the control end and the second end of the switching tube until the voltage is equal to the second level of the driving signal;

and in the normal working stage, the voltage between the control end and the second end of the switch tube keeps a second level, and the power supply supplies power to the capacitive load through the switched-on switch tube.

11. The operating method of the power supply device according to claim 10, wherein in the first starting stage, the voltage between the control terminal and the second terminal of the switching tube is approximately equal to the voltage of the capacitor unit, and the voltage between the control terminal and the second terminal of the switching tube and the voltage rising speed of the capacitor unit gradually decrease;

in the second starting stage, the voltage rising speed between the control end and the second end of the switch tube is gradually reduced;

in the third stage of starting, the voltage between the control end and the second end of the switch tube maintains a stable value;

in a fourth starting stage, the voltage rising speed between the control end and the second end of the switch tube is gradually reduced;

in the fifth starting stage, the voltage rising speed between the control end and the second end of the switch tube is gradually reduced until the voltage rising speed is zero.

12. The operating method of the power supply apparatus according to claim 10, wherein during the second phase of starting, the current flowing through the capacitive load is approximately equal to (vgs-vgs (th)) × gm, where vgs is the voltage between the control terminal and the second terminal of the switching transistor, vgs (th) is the turn-on threshold of the switching transistor, and gm is the transconductance of the switching transistor;

starting the third stage, the current flowing through the capacitive load is equal to Cout ((V2-vgs 1)

And V1 (R1 × C1)), where Cout is a capacitance value of the capacitive load, V2 is a voltage value of the second level of the driving signal, R1 is a resistance value of the first resistor unit, and C1 is a capacitance value of the capacitor unit.

13. The operating method of the power supply apparatus according to claim 10, wherein when the electronic fuse is required to be turned off, the driving signal outputted from the first terminal of the driving signal generating unit is switched from the second level to the first level, the first diode is turned on, and the voltage from the control terminal to the second terminal of the switching tube is discharged through the series connection of the resistor and the diode and the driving signal generating unit until the switching tube is turned off.

14. The operating method of the power supply apparatus according to claim 13, wherein when the electronic fuse is required to be turned off, the voltage across the capacitor unit is discharged through the series arrangement of the resistance diode, the driving signal generating unit and the capacitive load.

15. The operating method of the power supply apparatus according to claim 13, wherein when the electronic fuse is required to be turned off, the voltage across the capacitor unit is discharged through the third resistor unit, the resistor-diode series structure, the driving signal generating unit and the capacitive load.

16. The operating method of the power supply apparatus according to claim 10, wherein when the driving signal output from the first terminal of the driving signal generating unit is at the first level, the transistor is turned on, and the voltage across the capacitor unit is discharged through the transistor and the fourth resistor unit.