Double-threshold over-current detection protection circuit

Abstract

The invention relates to a double-threshold overcurrent detection protection circuit, and belongs to the technical field of circuit protection. According to the dual-threshold detection protection circuit, through setting different current detection thresholds, an overcurrent state can be accurately identified, a problem that the overcurrent state cannot be latched is effectively solved, stable operation of the circuit is guaranteed, and abnormal operation of equipment caused by intermittent protection is avoided.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of circuit protection, and particularly relates to a double-threshold overcurrent detection protection circuit. BACKGROUND

[0002] In the field of electronic circuits, overcurrent protection is a key technical means to ensure the safe and stable operation of circuits and related electronic devices. With the rapid development of electronic technology, various electronic devices are becoming increasingly complex, and higher requirements are placed on the precision, reliability and timeliness of the response of overcurrent protection.

[0003] In the application scenario of parallel inductive circuits, there is a technical problem of intermittent protection caused by the difficulty of effectively latching the overcurrent state. This intermittent protection can cause the circuit to frequently switch between normal working state and protection state, which interferes with the normal operation of the circuit and related devices, and reduces the service life and working reliability of the devices.

[0004] Most traditional overcurrent protection circuits use single threshold detection. Single threshold detection cannot accurately distinguish between normal current fluctuations and real overcurrent faults, and is prone to false protection actions. Moreover, the flexibility and reliability of protection are poor, and it is difficult to meet the high performance requirements of modern electronic devices for overcurrent protection.

[0005] In summary, it is of great significance to develop an overcurrent protection circuit that can solve the above problems. SUMMARY

[0006] (I) Technical problem to be solved

[0007] The technical problem to be solved by the present application is to provide a double-threshold overcurrent detection protection circuit to realize more reliable overcurrent protection of the circuit, in order to solve the intermittent protection problem caused by the inability to latch the overcurrent state in parallel inductive circuits.

[0008] (II) Technical solution

[0009] In order to solve the above technical problems, the present application provides a double-threshold overcurrent detection protection circuit, which comprises a clamping protection unit, a threshold setting unit, a comparison unit and a logic and amplitude detection unit.

[0010] The clamping protection unit comprises diodes D1 and D2, which are used to clamp the voltage across the input current I IN to limit the voltage across the input current I IN within a safe range;

[0011] The threshold setting unit comprises resistors R1 and R2, and switches S1 and S2. By controlling the on-off of switches S1 and S2, resistor R1 or R2 is selected to be connected, so as to adjust the threshold value of overcurrent detection.

[0012] Comparison Unit: Includes comparators G1 and G2, used to compare the input voltage with a set threshold voltage. When the input voltage exceeds the threshold voltage, the comparator output state changes, thereby triggering subsequent overcurrent protection actions.

[0013] Logic and amplitude detection unit: includes an OR gate, amplitude detection circuit and comparators V1 and V2, used to perform logic processing and amplitude detection on the signal to determine whether overcurrent protection is triggered;

[0014] Wherein, the input current I IN A parallel network consisting of diodes D1 and D2, switch S1 connected in series with resistor R1, and switch S2 connected in series with resistor R2 is connected to ground at one end.

[0015] The connection point of switch S1 and resistor R1 is connected to the inverting input of comparator G1, and the non-inverting input of G1 is connected to the reference voltage; the connection point of switch S2 and resistor R2 is connected to the inverting input of comparator G2, and the non-inverting input of G2 is connected to the reference voltage.

[0016] The output signals VO1 and VO2 of comparator G1 are combined into a total output signal VO, and each is connected to the corresponding amplitude detection circuit.

[0017] The output of the amplitude detection circuit is connected to the non-inverting input of comparators V1 and V2 respectively, and the voltage thresholds VT1 and VT2 are input to the inverting inputs of V1 and V2 one-to-one respectively.

[0018] The output signals PT1 of comparator V1 and PT2 of comparator V2, together with the control signal CTR1, are connected to the input of the OR gate. The output of the OR gate feeds back the control level to the threshold setting unit at the front end to control the switch S1.

[0019] The present invention also provides a method for operating the circuit.

[0020] The present invention also provides a method of using the circuit.

[0021] The present invention also provides an application of the circuit in the field of circuit protection technology.

[0022] The present invention also provides an application of the method in the field of circuit protection technology.

[0023] (III) Beneficial Effects

[0024] The dual-threshold overcurrent detection and protection circuit of this invention has the following advantages:

[0025] (1) Intermittent protection problem

[0026] In parallel induction circuits, a common problem is that overcurrent states cannot be effectively latched, leading to intermittent protection. This dual-threshold detection protection circuit, by setting different current detection thresholds, can accurately identify overcurrent states, effectively solving the problem of overcurrent states not being latched, ensuring stable circuit operation, and avoiding equipment malfunctions caused by intermittent protection.

[0027] (2) Flexible detection with dual thresholds

[0028] The circuit is configured with two different current thresholds for more precise overcurrent detection. When the current reaches the lower first current threshold I... T2 When the current continues to rise and reaches a higher second current threshold I, the circuit can issue a warning signal, indicating a potential overcurrent risk. T1 In such cases, protective measures such as cutting off the circuit are then taken. This tiered approach, compared to single threshold detection, significantly reduces the probability of malfunctions caused by instantaneous current fluctuations, thus improving the reliability and accuracy of the protection.

[0029] (3) Clamping protection enhances safety

[0030] Diodes D1 and D2 in the circuit form a clamping protection circuit, which can reduce the input current I. IN The voltage across the terminals is limited to a certain range. This effectively prevents damage to other components in the circuit due to overvoltage, enhancing the circuit's safety and stability under abnormal conditions.

[0031] (4) Highly adjustable

[0032] By selecting different resistors (R1, R2) using switches S1 and S2, the overcurrent detection threshold can be easily adjusted. This allows the circuit to flexibly set protection parameters according to different application scenarios and requirements, exhibiting strong adaptability and adjustability. Attached Figure Description

[0033] Figure 1 This is the circuit schematic diagram of the present invention;

[0034] Figure 2 This is a circuit flowchart of the present invention. Detailed Implementation

[0035] To make the objectives, contents, and advantages of the present invention clearer, the specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples.

[0036] refer to Figure 1 The present invention provides a dual-threshold overcurrent detection and protection circuit, comprising a clamping protection unit, a threshold setting unit, a comparison unit, and a logic and amplitude detection unit. The specific circuit composition and functions are as follows:

[0037] Clamping protection unit: includes diodes D1 and D2, used to clamp the input current I. IN The voltage at both ends is clamped to limit the I. IN The voltage at both ends is within a safe range;

[0038] Threshold setting unit: includes resistors R1 and R2 and switches S1 and S2. By controlling the on / off state of switches S1 and S2, resistors R1 or R2 can be selected to be connected, thereby adjusting the threshold value for overcurrent detection.

[0039] Comparison Unit: Includes comparators G1 and G2, used to compare the input voltage signal with a set threshold voltage. When the input voltage exceeds the threshold voltage, the output state of the comparator changes, thereby triggering subsequent overcurrent protection actions.

[0040] Logic and amplitude detection unit: includes an OR gate, amplitude detection circuit and comparators V1 and V2, used to perform logic processing and amplitude detection on the signal to determine whether overcurrent protection is triggered.

[0041] Specifically, the circuit connection is as follows:

[0042] Input current I IN A parallel network consisting of diodes D1 and D2, switch S1 connected in series with resistor R1, and switch S2 connected in series with resistor R2 is connected to ground at one end.

[0043] The connection point of switch S1 and resistor R1 is connected to the inverting input of comparator G1, and the non-inverting input of G1 is connected to the reference voltage; the connection point of switch S2 and resistor R2 is connected to the inverting input of comparator G2, and the non-inverting input of G2 is connected to the reference voltage.

[0044] The output signals VO1 and VO2 of comparator G1 are combined into a total output signal VO, and each is connected to the corresponding amplitude detection circuit.

[0045] The output of the amplitude detection circuit is connected to the non-inverting input of comparator V1 (corresponding to the VO1 path) and V2 (corresponding to the VO2 path), respectively, and the voltage thresholds VT1 and VT2 are respectively input to the inverting input of V1 and V2 one-to-one;

[0046] The output signals PT1 of comparator V1 and PT2 of comparator V2, together with the control signal CTR1, are connected to the input of the OR gate. The output of the OR gate feeds back the control level to the threshold setting unit at the front end to control the switch S1.

[0047] The working principle of the dual-threshold overcurrent detection and protection circuit of this invention is as follows:

[0048] Switch S1 closes when the control level is high and opens when it is low. CTR1 is the switch operation command sent by the external system controller. The output signals VO1 and VO2 of G1 and G2 (amplifier circuit output signals) are detected by the amplitude detection circuit and then compared with the voltage thresholds VT1 and VT2 of the comparator circuit by comparators V1 and V2 respectively, generating overcurrent detection signals PT1 and PT2. The switch operation command CTR1 is ORed with PT1 and PT2 by an OR gate, and the output control level controls switch S1. When any one of the three input signals of the OR gate—CTR1, PT1, and PT2—is high, switch S1 closes.

[0049] Where R2 is a large-value sensing resistor covering a smaller range, and R1 is a small-value sensing resistor covering a larger range. Let the maximum allowable current through sensing resistors R1 and R2 be I0 and I1, respectively. T1 and I T2 Define the input current threshold at which PT1 flips as I. T1 ′.

[0050] The detailed working principle is as follows:

[0051] (1) Initial detection state: The user selects a lower current range, switch S2 is closed, and the switch operation command CTR1 = 0, causing switch S1 to open. At this time, the circuit is in the basic detection stage. For the input current I... IN Perform the first threshold detection.

[0052] (2) First threshold detection: (determine whether I) IN >I T2 )

[0053] If I IN ≤I T2 This indicates that the current current has not exceeded the first threshold I. T2 The circuit remains in its initial state and continues to monitor changes.

[0054] If I IN >I T2 At this time, PT2 = 1 is triggered; switch S1 is closed. The input current I is... IN The current is diverted and gradually returns to normal, at which point the circuit enters the second threshold detection stage.

[0055] (3) Second threshold detection (determining whether I) IN >I T1 ′, I T1 ′>I T2 )

[0056] If I IN >I T1When the overcurrent detection signal PT1 changes from low level to high level, PT1 = 1; at the same time, switch S1 closes.

[0057] If I IN ≤I T1 ', PT1=0; the current I through R2 R2 <I T2 PT2 = 0; switch S1 is open. The circuit returns to its initial detection state.

[0058] Traditional circuits, first threshold judgment, I IN >I T2 At that time, the current through R2 (the current induced in R2) decreases to (1 / 11 - 1 / 5) × I IN At this time, I R2 Below the threshold I T2 If the protection condition is no longer met, switch S1 will open; after switch S1 opens, IR2 = I IN >I T2 This will trigger the protection again, causing switch S1 to close. The circuit switches back and forth between the protected and unprotected states, resulting in intermittent protection.

[0059] Depend on Figure 2 It can be seen that in this invention, I IN >I T2 During this period, the protection circuit continues to operate; when the overcurrent condition disappears, and I... IN ≤I T1 When the threshold is reached, the protection state automatically exits. The aforementioned dual-threshold overcurrent detection protection circuit achieves overcurrent detection state locking, compensating for the deficiencies in the parallel shunt protection mechanism and preventing intermittent protection.

[0060] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A dual-threshold overcurrent detection and protection circuit, characterized in that, It includes a clamping protection unit, a threshold setting unit, a comparison unit, and a logic and amplitude detection unit; Clamping protection unit: includes diodes D1 and D2, used to clamp the input current I. IN The voltage at both ends is clamped to limit the I. IN The voltage at both ends is within a safe range; Threshold setting unit: includes resistors R1 and R2 and switches S1 and S2. By controlling the on / off state of switches S1 and S2, resistors R1 or R2 can be selected to be connected, thereby adjusting the threshold value for overcurrent detection. Comparison Unit: Includes comparators G1 and G2, used to compare the input voltage with a set threshold voltage. When the input voltage exceeds the threshold voltage, the comparator output state changes, thereby triggering subsequent overcurrent protection actions. Logic and amplitude detection unit: includes an OR gate, amplitude detection circuit and comparators V1 and V2, used to perform logic processing and amplitude detection on the signal to determine whether overcurrent protection is triggered; Wherein, the input current I IN A parallel network consisting of diodes D1 and D2, switch S1 connected in series with resistor R1, and switch S2 connected in series with resistor R2 is connected to ground at one end. The connection point of switch S1 and resistor R1 is connected to the inverting input of comparator G1, and the non-inverting input of G1 is connected to the reference voltage; the connection point of switch S2 and resistor R2 is connected to the inverting input of comparator G2, and the non-inverting input of G2 is connected to the reference voltage. The output signals VO1 and VO2 of comparator G1 are combined into a total output signal VO, and each is connected to the corresponding amplitude detection circuit. The output of the amplitude detection circuit is connected to the non-inverting input of comparators V1 and V2 respectively, and the voltage thresholds VT1 and VT2 are input to the inverting inputs of V1 and V2 one-to-one respectively. The output signals PT1 of comparator V1 and PT2 of comparator V2, together with the control signal CTR1, are connected to the input of the OR gate. The output of the OR gate feeds back the control level to the threshold setting unit at the front end to control switch S1.

2. The protection circuit as described in claim 1, characterized in that, Switch S1 is closed when the control level is high and open when it is low. The output signals VO1 and VO2 of G1 and G2 are detected by the amplitude detection circuit and then compared with the voltage thresholds VT1 and VT2 by comparators V1 and V2 respectively, generating overcurrent detection signals PT1 and PT2. The control signal CTR1 is ORed with PT1 and PT2 by an OR gate, and the output control level controls switch S1. When any one of the three input signals of the OR gate, CTR1, PT1, and PT2, is high, switch S1 is closed.

3. The protection circuit as described in claim 2, characterized in that, R2 is a large-value sensing resistor, and R1 is a small-value sensing resistor; let the maximum allowable current through sensing resistors R1 and R2 be I0 and I1, respectively. T1 and I T2 Define the input current threshold at which PT1 flips as I. T1 Then we have: (1) Initial detection state: Switch S2 is closed, switch operation command CTR1 = 0, switch S1 is open. At this time, the protection circuit is in the basic detection stage. Next, the input current I is measured. IN Perform the first threshold detection; (2) First threshold detection: If I IN ≤I T2 The protection circuit maintains the initial detection state and continues to monitor changes; If I IN >I T2 At this point, PT2 = 1 is triggered; Switch S1 is closed; input current I IN The current is diverted, and the protection circuit then enters the second threshold detection stage. (3) Second threshold detection If I IN >I T1 When the overcurrent detection signal PT1 changes from low to high, PT1 = 1; at the same time, switch S1 closes. If I IN ≤I T1 ', PT1=0; the current I through R2 R2 <I T2 PT2 = 0; switch S1 is open, and the protection circuit returns to its initial detection state.

4. The protection circuit as described in claim 3, characterized in that, In the second threshold detection stage, I T1 ′>I T2 .

5. The protection circuit as described in claim 1, characterized in that, The control signal CTR1 is a switching operation command sent by an external system controller.

6. The protection circuit as described in claim 1, characterized in that, This protection circuit can lock the overcurrent detection status.

7. A method of operating the circuit as described in any one of claims 1 to 6.

8. A method of using the circuit as described in any one of claims 1 to 6.

9. The application of the circuit as described in any one of claims 1 to 6 in the field of circuit protection technology.

10. An application of the method as described in claim 7 in the field of circuit protection technology.

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