CN-122026269-A - Alternating current electronic switching circuit for overcurrent protection and working method thereof

CN122026269ACN 122026269 ACN122026269 ACN 122026269ACN-122026269-A

Abstract

The invention belongs to the technical field of power electronics, and relates to an alternating current electronic switching circuit for overcurrent protection and a working method thereof. The power switch comprises a power switch unit, a driving unit, a current detection unit and a current detection unit, wherein the input end of the power switch unit is connected with an input voltage end of a circuit, the output end of the power switch unit is connected with an output end of the circuit, the input end of the driving unit is connected with an external driving signal input end H1, the output end of the driving unit is connected with a control end of the power switch unit, the driving unit is used for transmitting a received driving signal to the power switch unit, the detection end of the current detection unit is connected with the power switch unit, the control end of the current detection unit is connected with the driving unit, and the current detection unit is used for cutting off a driving signal transmission path from the driving unit to the power switch unit when current flowing through the power switch unit flows excessively. The invention realizes the rapid identification and reliable protection of the overcurrent state, and remarkably improves the safe operation capability of the circuit under the abnormal current condition.

Inventors

CHEN GUANGHUI
WANG JUNHUA
DENG ERNING

Assignees

天水七四九电子有限公司

Dates

Publication Date: 20260512
Application Date: 20260120

Claims (10)

1. An ac electronic switching circuit for overcurrent protection, comprising: The input end of the power switch unit is connected with the input voltage end of the circuit, and the output end of the power switch unit is connected with the output end of the circuit; The input end of the driving unit is connected with an external driving signal input end H1, and the output end of the driving unit is connected with the control end of the power switch unit; the driving unit is used for transmitting the received driving signal to the power switch unit; The power switch unit comprises a power switch unit, a current detection unit, a control unit and a control unit, wherein the power switch unit is connected with the power switch unit, the detection end of the current detection unit is connected with the power switch unit, and the control end of the current detection unit is connected with the drive unit, and the current detection unit is used for cutting off a drive signal transmission path from the drive unit to the power switch unit when current flowing through the power switch unit flows through the power switch unit.
2. An ac electronic switching circuit for overcurrent protection according to claim 1, wherein the power switching unit includes a first MOS transistor M1 and a second MOS transistor M2; the drain electrode of the first MOS tube M1 is connected to the input voltage end, and the source electrode of the first MOS tube M1 is connected with the source electrode of the second MOS tube M2; The drain electrode of the second MOS tube M2 is connected to the output end of the power switch unit; the grid electrode of the first MOS tube M1 is connected with the grid electrode of the second MOS tube M2, and is used as the control end of the power switch unit together, and is connected with the output end of the driving unit.
3. An ac electronic switching circuit for overcurrent protection according to claim 2, wherein the driving unit includes a first resistor R1, the current detecting unit includes a fifth resistor R5; The first end of the fifth resistor R5 and the first end of the first resistor R1 are both connected to the external driving signal input end H1, the second end of the fifth resistor R5 is connected to the control end of the power switch unit, and the second end of the first resistor R1 is connected with the grid electrode of the first MOS tube M1 and the grid electrode of the second MOS tube M2 respectively.
4. An ac electronic switching circuit for overcurrent protection according to claim 3, wherein the current detection unit further comprises a second resistor R2 and a second diode D2; The first end of the second resistor R2 is connected with the second end of the fifth resistor R5, and the second end of the second resistor R2 is connected with the anode of the second diode D2; the cathode of the second diode D2 is connected to the input terminal of the power switch unit.
5. An ac electronic switching circuit for over-current protection according to claim 4, wherein said current detection unit further comprises a voltage division sampling module, a switching device Q1, and a feedback path; the sampling point of the partial pressure sampling module is connected with the control end of the switching device Q1, and the partial pressure sampling module is used for obtaining a sampling signal reflecting the current flowing through the power switching unit; The output end of the switching device Q1 is connected to the control end of the driving unit through the feedback path; when the sampling signal indicates overcurrent, the switching device Q1 is turned on, and the output signal of the driving unit is disabled through the feedback path, thereby cutting off the driving signal transmission path.
6. An ac electronic switching circuit for over-current protection according to claim 5, wherein said switching device Q1 is an NPN transistor; The voltage division sampling module comprises a third resistor R3, a fourth resistor R4 and a capacitor C1; The first end of the third resistor R3 is connected with the base electrode of the switching device Q1, and the second end of the third resistor R3 is connected with the output end of the driving unit; the fourth resistor R4 and the capacitor C1 are connected in parallel between the base electrode and the emitter electrode of the switching device Q1; an emitter of the switching device Q1 is connected to a source of the first MOS transistor M1.
7. An ac electronic switching circuit for overcurrent protection according to claim 6, wherein the feedback path includes a first diode D1; the second end of the third resistor R3 is connected with the anode of the first diode D1; The cathode of the first diode D1 is connected to the second resistor R2.
8. The ac electronic switching circuit for overcurrent protection according to claim 1, wherein the current detection unit uses the on internal resistance of the MOS transistor in the power switching unit as a sampling resistor, and reflects the magnitude of the load current by detecting the voltage between the source and the ground when the MOS transistor is turned on.
9. An ac electronic switching circuit for over-current protection according to claim 1, wherein the current detecting unit maintains an off state of the power switching unit after the over-current protection is triggered, and the power switching unit resumes on when the driving signal provided from the external driving signal input terminal H1 jumps from an inactive level to an active level.
10. The working method of an ac electronic switching circuit for overcurrent protection according to any one of claims 1 to 9, comprising the steps of: S1, providing an effective driving signal through an external driving signal input end H1, and transmitting the signal to a control end of a power switch unit by a driving unit to drive the power switch unit to be conducted so as to form a current path between an input voltage end and an output end of the circuit; When the current is detected to exceed a preset threshold value, the current detection unit acts on the driving unit through a control end of the current detection unit, cuts off a driving signal transmission path from the driving unit to the power switch unit, maintains the cut-off state, and enables the power switch unit to enter and keep cut-off; And S3, when the driving signal provided by the external driving signal input end H1 jumps from the invalid level to the valid level again, the driving unit resumes transmitting the driving signal to the power switch unit, so that the power switch unit resumes conducting.

Description

Alternating current electronic switching circuit for overcurrent protection and working method thereof Technical Field The invention belongs to the technical field of power electronics, and relates to an alternating current electronic switching circuit for overcurrent protection and a working method thereof. Background In the technical field of power electronics, on-off control of alternating current or direct current power supply voltage is a basic functional requirement in industrial automation, smart grids and consumer electronics equipment, and is widely applied to motor driving, lighting control, power management and other scenes. In order to realize voltage on-off, a relay with a mechanical contact or a solid-state relay is generally adopted in the prior art as a core control element, wherein the mechanical contact relay drives a metal contact to realize circuit on-off through an electromagnetic mechanism, and the solid-state relay utilizes optocoupler isolation to combine with a semiconductor switching device to complete non-contact control. In addition, a part of electronic switching circuits adopt semiconductor devices to construct a high-frequency switching path, and the on-off state of main current is regulated and controlled through external driving signals so as to meet the application requirements of quick response. However, in the prior art, circuitry is at risk of functional failure when the load current flowing through the circuit exceeds a safety threshold. Disclosure of Invention The invention provides an alternating current electronic switch circuit for overcurrent protection and a working method thereof, which solve the problems in the prior art, realize the rapid identification and reliable protection of the overcurrent state and obviously improve the safe operation capability of the circuit under the abnormal current condition. In order to achieve the purpose, the invention is realized by adopting the following technical scheme: in a first aspect, the present invention provides an ac electronic switching circuit for overcurrent protection, comprising: The input end of the power switch unit is connected with the input voltage end of the circuit, and the output end of the power switch unit is connected with the output end of the circuit; The input end of the driving unit is connected with an external driving signal input end H1, and the output end of the driving unit is connected with the control end of the power switch unit; the driving unit is used for transmitting the received driving signal to the power switch unit; The power switch unit comprises a power switch unit, a current detection unit, a control unit and a control unit, wherein the power switch unit is connected with the power switch unit, the detection end of the current detection unit is connected with the power switch unit, and the control end of the current detection unit is connected with the drive unit, and the current detection unit is used for cutting off a drive signal transmission path from the drive unit to the power switch unit when current flowing through the power switch unit flows through the power switch unit. Preferably, the power switch unit comprises a first MOS tube M1 and a second MOS tube M2; the drain electrode of the first MOS tube M1 is connected to the input voltage end, and the source electrode of the first MOS tube M1 is connected with the source electrode of the second MOS tube M2; The drain electrode of the second MOS tube M2 is connected to the output end of the power switch unit; the grid electrode of the first MOS tube M1 is connected with the grid electrode of the second MOS tube M2, and is used as the control end of the power switch unit together, and is connected with the output end of the driving unit. Preferably, the driving unit comprises a first resistor R1, and the current detection unit comprises a fifth resistor R5; The first end of the fifth resistor R5 and the first end of the first resistor R1 are both connected to the external driving signal input end H1, the second end of the fifth resistor R5 is connected to the control end of the power switch unit, and the second end of the first resistor R1 is connected with the grid electrode of the first MOS tube M1 and the grid electrode of the second MOS tube M2 respectively. Preferably, the current detection unit further includes a second resistor R2 and a second diode D2; The first end of the second resistor R2 is connected with the second end of the fifth resistor R5, and the second end of the second resistor R2 is connected with the anode of the second diode D2; the cathode of the second diode D2 is connected to the input terminal of the power switch unit. Preferably, the current detection unit further comprises a voltage division sampling module, a switching device Q1 and a feedback path; the sampling point of the partial pressure sampling module is connected with the control end of the switching device Q1, and the partial pressure