CN219625634U - A failure detection circuit and device for power devices on a main power circuit - Google Patents

Abstract

The utility model provides a failure detection circuit and a failure detection device for a power device on a main power loop, which relate to the technical field of circuit control, wherein voltage values at two ends of a power element are acquired in real time through a voltage sampling circuit, and whether the power device fails or not is judged by an MCU (micro controller Unit) according to the voltage values at the two ends of the power element acquired in real time by the voltage sampling circuit, wherein if the voltage values at the two ends of the power device acquired by the voltage acquisition circuit are the same, the MCU judges that the power device is normal; if the voltage values of the two ends of the power device collected by the voltage collecting circuit are different, the MCU judges that the power device is abnormal and controls the alarm circuit to alarm, so that the purpose of protecting equipment is achieved.

Description

A failure detection circuit and device for power devices on a main power circuit

technical field

The present application relates to the technical field of circuit control, in particular to a failure detection circuit and device for power devices on a main power circuit.

Background technique

Power devices are very important for electronic products. For example, a fuse is connected in series to the power input end of the circuit to control the total current of the entire circuit, or to control the switching element MOS tube for charging and discharging.

For the fuse, its working principle is to rely on the increased fault current after the circuit fails to flow through the fuse, causing it to heat up and melt itself, so as to cut off the power supply to achieve the purpose of protection. However, when the fuse FUSE is damaged or the fuse FUSE is aging due to long-term use (the aging of the device itself may exist after long-term use in units of years), the impedance of the fuse FUSE increases. When the fuse FUSE is damaged, the impedance becomes into infinity. Therefore, when the fuse FUSE is damaged, a large current discharge cannot be performed, which may easily cause unnecessary losses. Similarly, for a MOS tube, if it is detected to be closed when it is turned on, or it is detected to be turned on when it is turned off, it will inevitably cause damage to the device. However, the existing circuit does not have the function of detecting the failure of the power device on the main power circuit.

Utility model content

In order to overcome the deficiencies in the prior art, this application provides a failure detection circuit and device for power devices on the main power circuit, which can perform timely judgment and alarm when the power device on the main power circuit fails, so as to achieve the purpose of protecting equipment .

A failure detection circuit of a power device on a main power circuit provided by the present application includes a voltage acquisition circuit, an MCU and an alarm circuit, the voltage acquisition circuit is connected to the input end of the MCU, and the alarm circuit is connected to the MCU The output terminal is connected, and the voltage acquisition circuit includes a first voltage acquisition circuit and a second voltage acquisition circuit, the first voltage acquisition circuit is used to acquire the first voltage value of the power device near the end of the storage battery, and the second voltage acquisition circuit The circuit is used to collect the second voltage value of the end of the power device close to the charger.

In a possible implementation manner, the alarm circuit includes:

An alarm switch element, the control terminal of the alarm switch element is connected to the output terminal of the MCU; wherein, if the MCU judges that the power device is normal according to the voltage value at both ends of the power device collected by the voltage acquisition circuit, it sends a control The first control signal that the alarm switch element is disconnected; if the MCU judges that the power device is abnormal according to the voltage value at both ends of the power device collected by the voltage acquisition circuit, send the second control signal that controls the turn-on of the alarm switch element control signal.

In a possible implementation manner, the power device includes one or more of a fuse, a sampling resistor, and a charging and discharging MOS tube arranged on the main power circuit.

In a possible implementation manner, if the voltage values at both ends of the power device collected by the voltage collection circuit are the same, the MCU judges that the power device is normal; if the voltage values at both ends of the power device collected by the voltage collection circuit are not Similarly, the MCU judges that the power device is abnormal.

In a possible implementation manner, the first voltage acquisition circuit includes:

The first voltage divider circuit includes a first resistor R1, a third resistor R3 and a fifth resistor R5 connected in series, the first resistor R1 is connected to one end of the power harvesting device close to the storage battery, and the fifth resistor R5 is grounded;

The first amplifying circuit includes a first operational amplifier, the non-inverting input terminal of the first operational amplifier is connected between the third resistor R3 and the fifth resistor R5, the inverting input terminal is grounded through the seventh resistor R7, and the output terminal It is connected with the first ADC pin of the MCU, and the eighth resistor R8 is connected between the output terminal of the first operational amplifier and the inverting input terminal.

In a possible implementation manner, the second voltage acquisition circuit includes:

The second voltage divider circuit includes a second resistor R2, a fourth resistor R4 and a sixth resistor R6 connected in series, the second resistor R2 is connected to one end of the collection power device close to the charger, and the sixth resistor R6 is grounded ;

The second amplifying circuit includes a second operational amplifier, the noninverting input terminal of the second operational amplifier is connected between the fourth resistor R4 and the sixth resistor R6, the inverting input terminal is grounded through the ninth resistor R9, and the output terminal It is connected with the second ADC pin of the MCU, and the tenth resistor R10 is connected between the output terminal of the second operational amplifier and the inverting input terminal.

In a possible implementation manner, the alarm switch element is a PNP-type third transistor Q3, and the base of the third transistor Q3 is connected to the output terminal of the MCU through a thirteenth resistor R13. , its emitter is connected to the power supply through the fourteenth resistor R14, and its collector is grounded through the buzzer.

In a possible implementation manner, the buzzer is connected in parallel with a first diode D1, the anode of the first diode D1 is connected to the output terminal of the buzzer, and the cathode of the first diode D1 is connected to the output terminal of the buzzer. connected to the input of the device.

In a possible implementation manner, the first ADC pin of the MCU is grounded through the third capacitor C3, and the first ADC pin of the MCU is connected to the output of the first operational amplifier through the eleventh resistor R11 The second ADC pin of the MCU is grounded through the fourth capacitor C4, and the second ADC pin of the MCU is connected to the output end of the second operational amplifier through the twelfth resistor R12.

The application provides a failure detection device for a power device on a main power circuit, which adopts any one of the above-mentioned failure detection circuits for a power device on a main power circuit.

Compared with prior art, the beneficial effect of the present application:

The failure detection circuit and device of the power device on the main power circuit provided in this embodiment collects the voltage value at both ends of the power element in real time through the voltage sampling circuit, and the MCU judges the power according to the voltage value at both ends of the power element collected in real time by the voltage sampling circuit. Whether the device fails. Among them, if the voltage values at both ends of the power device collected by the voltage acquisition circuit are the same, the MCU judges that the power device is normal; An alarm is issued to protect the device.

Description of drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present utility model, so It should not be regarded as a limitation on the scope, and those skilled in the art can also obtain other related drawings according to these drawings without creative work.

FIG. 1 shows a circuit diagram of a failure detection circuit of a power device on a main power circuit according to Embodiment 1 of the present application;

FIG. 2 shows a circuit diagram of detecting whether the fuse F1 fails through the failure detection circuit according to the embodiment of the present application.

Description of main component symbols:

1. Voltage acquisition circuit, 2. MCU, 3. Alarm circuit.

Detailed ways

Embodiments of the present application are described in detail below, examples of which are shown in the drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the figures are exemplary, are only for explaining the present application, and should not be construed as limiting the present application.

In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", " Back", "Left", "Right", "Vertical", "Horizontal", "Top", "Bottom", "Inner", "Outer", "Clockwise", "Counterclockwise", "Axial" , "radial", "circumferential" and other indicated orientations or positional relationships are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the application and simplifying the description, rather than indicating or implying the referred device or Elements must have certain orientations, be constructed and operate in certain orientations, and thus should not be construed as limiting the application.

In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be interpreted as indicating or implying relative importance or implicitly specifying the quantity of indicated technical features. Thus, a feature defined as "first" and "second" may explicitly or implicitly include one or more of these features. In the description of the present application, "plurality" means two or more, unless otherwise specifically defined.

In this application, terms such as "installation", "connection", "connection" and "fixation" should be interpreted in a broad sense, for example, it can be a fixed connection or a detachable connection, unless otherwise clearly specified and limited. , or integrated; it can be mechanically connected or electrically connected; it can be directly connected or indirectly connected through an intermediary, and it can be the internal communication of two components or the interaction relationship between two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in this application according to specific situations.

In the present application, unless otherwise clearly specified and limited, a first feature being "on" or "under" a second feature may mean that the first and second features are in direct contact, or that the first and second features are indirect through an intermediary. touch. Moreover, "above", "above" and "above" the first feature on the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. "Below", "beneath" and "beneath" the first feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is less horizontally than the second feature.

In view of the technical problems raised by the background technology, this application provides a failure detection circuit and device for power devices on the main power circuit, which can perform timely judgment and alarm when the power device on the main power circuit fails, so as to achieve the purpose of protecting equipment.

Referring to Figure 1 of the specification, a failure detection circuit of a power device on a main power circuit provided by an embodiment of the present application includes a voltage acquisition circuit 1, an MCU2 and an alarm circuit 3, wherein the power device is arranged on the main power circuit Between the battery and the charger, the voltage acquisition circuit 1 includes a first voltage acquisition circuit and a second voltage acquisition circuit, the first voltage acquisition circuit is used to acquire the first voltage value of the power device near the end of the battery, the The second voltage acquisition circuit is used to acquire the second voltage value of the power device close to the charger; the input terminal of the MCU2 is connected to the first voltage acquisition circuit and the second voltage acquisition circuit, and is used to acquire the voltage according to the voltage acquisition circuit Whether the power device fails is judged by the voltage value at both ends of the power device; the alarm circuit 3 is connected to the output terminal of the MCU2, and is used to send an alarm according to the control signal sent after the MCU2 judges that the power device fails.

Wherein, the power device includes one or more of a fuse, a sampling resistor, and a charging and discharging MOS tube arranged on the main power circuit. When the fuse is normal, its resistance value is negligible, and when the fuse is abnormal, the impedance becomes infinite; When the resistance is abnormal, its resistance value becomes larger; when the charging and discharging MOS tube is normally turned on, it is regarded as a short circuit, and if it is turned off due to abnormal transmission during normal conduction, it is regarded as an open circuit. It can be seen that when the fuse, the sampling resistor or the charging and discharging MOS tube is normally turned on, the voltage values at both ends are the same.

Then, after the first voltage acquisition circuit and the second voltage acquisition circuit transmit the collected voltage values at both ends of the power device to the MCU, if the MCU detects that the voltage values at both ends of the power device are the same, then it is judged that the power device is normal; If the voltage values at both ends of the power device are different, it is judged that the power device is normal.

In one embodiment, the alarm circuit 3 includes an alarm switch element connected to the buzzer, and the control terminal of the alarm switch element is connected to the output end of the MCU2; The first control signal that the alarm switch element is disconnected disables the buzzer alarm; if MCU2 judges that the power device is abnormal, sends the second control signal that controls the conduction of the alarm switch element to make the buzzer alarm and prompt the maintenance personnel Replace power components.

In one embodiment, referring to Fig. 2 of the specification, the failure detection circuit provided by the present application is used to detect whether the fuse F1 fails. The first voltage acquisition circuit is used to acquire the first voltage value of the end of the fuse F1 close to the battery BAT+, and the second voltage acquisition circuit is used to acquire the second voltage value of the end of the fuse F1 close to the charger PACK+. The first voltage acquisition circuit includes a first voltage divider circuit and a first amplifier circuit, the first voltage divider circuit includes a first resistor R1, a third resistor R3 and a fifth resistor R5 connected in series, and the first resistor R1 Connected to one end of the acquisition fuse F1 close to the storage battery, the fifth resistor R5 is grounded; the first amplifier circuit includes a first operational amplifier, and the non-inverting input terminal of the first operational amplifier is connected to the third resistor R3 and the fifth resistor R5, the inverting input terminal of the first operational amplifier is grounded through the seventh resistor R7, the output terminal of the first operational amplifier is connected with the first ADC pin of the MCU, and the An eighth resistor R8 is connected between the output terminal of the first operational amplifier and the inverting input terminal. The second voltage acquisition circuit includes a second voltage divider circuit and a second amplifying circuit, the second voltage divider circuit includes a second resistor R2, a fourth resistor R4 and a sixth resistor R6 connected in series, and the second resistor R2 Connected to one end of the collection fuse F1 close to the charger, the sixth resistor R6 is grounded; the second amplifying circuit includes a second operational amplifier, and the non-inverting input terminal of the second operational amplifier is connected to the fourth resistor Between R4 and the sixth resistor R6, the inverting input terminal of the second operational amplifier is grounded through the ninth resistor R9, the output terminal of the second operational amplifier is connected to the second ADC pin of the MCU, and the A tenth resistor R10 is connected between the output terminal of the second operational amplifier and the inverting input terminal. The alarm switch element is a PNP third transistor Q3, and the base of the third transistor Q3 of the third transistor Q3 is connected to the output terminal of the MCU through a thirteenth resistor R13 , the emitter of the third transistor Q3 is connected to the power supply VCC2 through the fourteenth resistor R14, and the collector of the third transistor Q3 is grounded through the buzzer P1.

Further, the first ADC pin of the MCU2 is grounded through the third capacitor C3, and the first ADC pin of the MCU2 is connected to the output end of the first operational amplifier through the eleventh resistor R11; the MCU The second ADC pin of the MCU2 is grounded through the fourth capacitor C4, and the second ADC pin of the MCU2 is connected to the output terminal of the second operational amplifier through the twelfth resistor R12. Wherein, the eleventh resistor R11 and the third capacitor C3 are used for filtering the first ADC pin of the MCU2, and the twelfth resistor R12 and the fourth capacitor C4 are used for filtering the second ADC pin of the MCU2.

Further, the buzzer P1 is connected in parallel with a first diode D1, the anode of the first diode D1 is connected to the output terminal of the buzzer P1, and the cathode of the first diode D1 is connected to the output terminal of the buzzer P1. The input terminal of the buzzer P1 is connected. This is because the buzzer P1 is an inductive device, and the first diode D1 can be used as a freewheeling diode of the buzzer P1 to provide a discharge circuit for the reverse electromotive force and avoid damage to the third transistor Q3.

In addition, the failure detection circuit of the power device on the main power circuit provided by the present application also includes a power supply module for supplying power to the MCU2, the first operational amplifier, and the second operational amplifier.

In this embodiment, let the voltage value of the end of the fuse F1 close to the battery BAT be U1, the voltage value of the end close to the charger be U2, the voltage value of the non-inverting input terminal of the first operational amplifier be U3, and the non-inverting input terminal of the second operational amplifier The voltage value of terminal is U4, the voltage value of the first operational amplifier output terminal is U5, the voltage value of the second operational amplifier output terminal is U6, wherein, U3=U1*R5/(R1+R3+R5), U4=U2*R6/ (R2+R4+R6).

The battery takes 4S lithium iron phosphate battery as an example. The battery voltage is recorded as 13.5V under full charge. At the same time, R1=R2=100K, R3=R4=10K, R5=R6=10K, R7=R8=R9=R10=100K, Both the first operational amplifier and the second operational amplifier have a gain of 2.

Then, when the 4S lithium iron phosphate battery is discharged, the current flows from BAT+ to PACK+, and when the fuse F1 is normal, the voltage value U3 of the non-inverting input terminal of the first operational amplifier is the same as the voltage value U4 of the non-inverting input terminal of the second operational amplifier. 1.125V, the voltage value U5 of the output terminal of the first operational amplifier is the same as the voltage value U6 of the output terminal of the second operational amplifier, both of which are 2.25V, and the 0～3.3V of the first ADC pin and the second ADC pin of MCU2 At this time, the MCU determines that the fuse F1 is normal, outputs a high level to the base of the third transistor Q3, controls the third transistor Q3 to disconnect, and prohibits the buzzer alarm; when the fuse F1 fails, the impedance Infinity, regarded as an open circuit, the voltage value U3 of the non-inverting input terminal of the first operational amplifier is 1.125V, the voltage value U4 of the non-inverting input terminal of the second operational amplifier is zero, the voltage value U5 of the output terminal of the first operational amplifier is 2.25V, the second The voltage value U6 at the output terminal of the operational amplifier is zero. At this time, the MCU determines that the fuse F1 is abnormal, and outputs a low level to the base of the third transistor Q3 to control the conduction of the third transistor Q3, and the buzzer alarms to prompt maintenance. personnel to perform repairs.

When the charger is charging the 4S lithium iron phosphate battery, the current flow direction is from PACK+ to BAT+, the charger voltage is 14.8V, the voltage value U3 of the non-inverting input terminal of the first operational amplifier is the same as the voltage value U4 of the non-inverting input terminal of the second operational amplifier , are all 1.23V, the voltage value U5 of the output terminal of the first operational amplifier is the same as the voltage value U6 of the output terminal of the second operational amplifier, both are 2.46V, and at the first ADC pin of MCU2, the 0 of the second ADC pin In the range of ~3.3V, at this time, the MCU determines that the fuse F1 is normal, outputs a high level to the base of the third transistor Q3, controls the third transistor Q3 to disconnect, and prohibits the buzzer alarm; when the fuse F1 fails , the highest voltage on both sides of fuse F1 is: U1=13.5V full charge (SOC 100%), U2=14.8V; U3=1.125V, U4=1.23V, U5=2.25V, U6=2.26V, at this time the MCU It is determined that the fuse F1 is abnormal, and outputs a low level to the base of the third transistor Q3 to control the conduction of the third transistor Q3, and the buzzer gives an alarm, prompting the maintenance personnel to perform maintenance.

In other embodiments, the failure detection circuit of the power device on the main power circuit provided by the present application can also be used to detect whether the sampling resistor Rsen and the charging and discharging MOS transistors Q1 and Q2 are abnormal, and the detection principle is the same as the above-mentioned detection whether the fuse F1 is abnormal The working principle is similar and will not be repeated here.

The failure detection circuit of a power device on the main power circuit provided by this application detects whether the power element is abnormal by collecting the voltage value at both ends of the power element in real time and judging whether the voltage value at both ends of the power element is the same, and if abnormal, it will give a timely alarm , to remind the staff to overhaul or shut down the system directly, so as to protect the equipment.

The utility model also provides a failure detection device for power devices on the main power circuit. The above-mentioned failure detection circuit for power devices on the main power circuit can solve the risk caused by abusing power supply charging with a voltage lower than the standard. Since the problem-solving principle of the control device in the embodiment of the present application is similar to that of the above-mentioned control circuit in the embodiment of the present application, the implementation of the control device can refer to the implementation of the control circuit, and repeated descriptions will not be repeated.

In the description of this specification, descriptions referring to the terms "one embodiment", "some embodiments", "example", "specific examples", or "some examples" mean that specific features described in connection with the embodiment or example , structure, material or characteristic is included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the described specific features, structures, materials or characteristics may be combined in any suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples and features of different embodiments or examples described in this specification without conflicting with each other.

Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limitations on the present application, and those skilled in the art can make the above-mentioned The embodiments are subject to changes, modifications, substitutions and variations.

Claims (10)

1. A failure detection circuit of a power device on a main power loop, characterized in that, comprises a voltage acquisition circuit, an MCU and an alarm circuit, the voltage acquisition circuit is connected to the input of the MCU, and the alarm circuit is connected to the The output terminal of the MCU is connected, and the voltage acquisition circuit includes a first voltage acquisition circuit and a second voltage acquisition circuit, the first voltage acquisition circuit is used to acquire the first voltage value of the power device near the storage battery end, and the second The voltage acquisition circuit is used to acquire the second voltage value of the end of the power device close to the charger. 2. The failure detection circuit of a power device on a main power loop according to claim 1, wherein the alarm circuit comprises: An alarm switch element, the control terminal of the alarm switch element is connected to the output terminal of the MCU; wherein, if the MCU judges that the power device is normal according to the voltage value at both ends of the power device collected by the voltage acquisition circuit, it sends a control The first control signal that the alarm switch element is disconnected; if the MCU judges that the power device is abnormal according to the voltage value at both ends of the power device collected by the voltage acquisition circuit, send the second control signal that controls the turn-on of the alarm switch element control signal. 3. The failure detection circuit of a power device on a main power circuit according to claim 1, wherein the power device comprises one of a fuse, a sampling resistor, and a charging and discharging MOS tube arranged on the main power circuit or more. 4. The failure detection circuit of a power device on a main power loop according to claim 2, wherein if the voltage values at both ends of the power device collected by the voltage acquisition circuit are the same, the MCU judges that the power device is normal ; If the voltage values at both ends of the power device collected by the voltage collection circuit are different, the MCU judges that the power device is abnormal. 5. The failure detection circuit of a power device on the main power loop according to claim 4, wherein the first voltage acquisition circuit comprises: The first voltage divider circuit includes a first resistor R1, a third resistor R3 and a fifth resistor R5 connected in series, the first resistor R1 is connected to one end of the power harvesting device close to the storage battery, and the fifth resistor R5 is grounded; The first amplifying circuit includes a first operational amplifier, the non-inverting input terminal of the first operational amplifier is connected between the third resistor R3 and the fifth resistor R5, the inverting input terminal is grounded through the seventh resistor R7, and the output terminal It is connected with the first ADC pin of the MCU, and the eighth resistor R8 is connected between the output terminal of the first operational amplifier and the inverting input terminal. 6. The failure detection circuit of a power device on the main power loop according to claim 5, wherein the second voltage acquisition circuit comprises: The second voltage divider circuit includes a second resistor R2, a fourth resistor R4 and a sixth resistor R6 connected in series, the second resistor R2 is connected to one end of the collection power device close to the charger, and the sixth resistor R6 is grounded ; The second amplifying circuit includes a second operational amplifier, the noninverting input terminal of the second operational amplifier is connected between the fourth resistor R4 and the sixth resistor R6, the inverting input terminal is grounded through the ninth resistor R9, and the output terminal It is connected with the second ADC pin of the MCU, and the tenth resistor R10 is connected between the output terminal of the second operational amplifier and the inverting input terminal. 7. The failure detection circuit of a power device on the main power circuit according to claim 6, wherein the alarm switch element is a PNP-type third transistor Q3, and the third transistor Q3 The base is connected to the output terminal of the MCU through the thirteenth resistor R13, the emitter is connected to the power supply through the fourteenth resistor R14, and the collector is grounded through the buzzer. 8. A failure detection circuit for power devices on the main power circuit according to claim 7, wherein the buzzer is connected in parallel with a first diode D1, and the anode of the first diode D1 is connected to the anode of the first diode D1. The output end of the buzzer is connected, and its cathode is connected to the input end of the buzzer. 9. The failure detection circuit of a power device on a main power loop according to claim 8, wherein the first ADC pin of the MCU is grounded through a third capacitor C3, and the first ADC pin of the MCU is grounded. The pin is connected to the output end of the first operational amplifier through the eleventh resistor R11; the second ADC pin of the MCU is grounded through the fourth capacitor C4, and the second ADC pin of the MCU is connected through the twelfth resistor R12 is connected with the output terminal of the second operational amplifier. 10. A failure detection device of a power device on a main power circuit, characterized in that it comprises the failure detection circuit of a power device on a main power circuit according to any one of claims 1-9.