CN111064159A - Current-limiting protection circuit and control method thereof - Google Patents
Current-limiting protection circuit and control method thereof Download PDFInfo
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/08—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/006—Calibration or setting of parameters
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/02—Details
- H02H3/05—Details with means for increasing reliability, e.g. redundancy arrangements
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/08—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current
- H02H3/087—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current for DC applications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/08—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current
- H02H3/093—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current with timing means
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Abstract
本发明公开一种限流保护电路及其控制方法，设于电源端与设备端之间，包括含有第一开关件的第一回路以及含有第二开关件的第二回路，第一回路接通电源端与设备端并且由第一开关件控制其通断，第二回路连接电源端与地并由第二开关件控制其通断，上述第一开关件采用PMOS管，由并联在其源极和栅极之间的触发电阻R5提供导通电压，第二开关件采用开关三极管Q2，其电阻模块串接于第一回路中，当第一回路中的电流升高至设定值后，上述开关三极管Q2导通，触发电阻R5被短接，第一开关件断开，第一回路断开，由此实现限流保护的目的，由于电阻模块设置为多个第一电阻并联的形式且其中至少一个第一电阻设置为可调电阻，由此可以调节限流保护电路限流的上限值。
The invention discloses a current limiting protection circuit and a control method thereof, which are arranged between a power supply terminal and an equipment terminal, and include a first loop including a first switching element and a second loop including a second switching element, and the first loop is connected to The power supply terminal and the equipment terminal are controlled by the first switch element, and the second loop connects the power supply terminal and the ground and is controlled by the second switch element. The trigger resistor R5 between the gate and the gate provides a turn-on voltage, the second switching element adopts the switching transistor Q2, and its resistance module is connected in series in the first loop. When the current in the first loop rises to the set value, the above The switching transistor Q2 is turned on, the trigger resistor R5 is short-circuited, the first switching element is disconnected, and the first loop is disconnected, thereby achieving the purpose of current limiting protection. The at least one first resistor is set as an adjustable resistor, so that the upper limit value of the current limit of the current limiting protection circuit can be adjusted.
Description
Technical Field
The present invention relates to a protection circuit, and more particularly, to a current limiting protection circuit and a control method thereof.
Background
When a plurality of devices (such as chips) are powered by an external power supply, if the devices are short-circuited or power consumption is suddenly increased, the output of the external power supply is increased, and thus other devices are affected. Since each device needs to operate normally at a rated power, when the current suddenly increases, the current between the external power source and the device needs to be limited.
In the current limiting circuit in the prior art, as shown in fig. 1, when the current is less than the set value, the bias current of Q1 is provided by R1, Q1 is in saturation conduction, and the current is not controlled; when the current is larger than or equal to the set value, the voltage drop on R is increased, the sum of the voltage drop on R and the junction voltage of the triode is close to the voltage drop of R2, and then the current passing through Q1 is limited, so that the current is limited to a certain level. However, it can be seen from the above current limiting circuit that the magnitude of the current limiting is not easy to determine and adjust.
Disclosure of Invention
In view of the problems in practical applications, an object of the present invention is to provide a current-limiting protection circuit, which can adjust an upper limit value of a current limit, reduce a heat value of a single resistor, and improve stability of the circuit, and based on the current-limiting protection circuit, an object of the present invention is to provide a control method of the current-limiting protection circuit, and the specific scheme is as follows:
a current-limiting protection circuit is arranged between a power supply end and an equipment end, and comprises:
one end of the first loop is electrically connected with the power supply end, the other end of the first loop is connected with a first switching piece, an equipment end input interface and an equipment end output interface in sequence and then grounded, the first switching piece is connected and configured with a first trigger piece, and the first switching piece responds to the trigger state of the first trigger piece to control the on-off of the first loop;
one end of the second loop is electrically connected with the power supply end, the other end of the second loop is connected with a second switch piece and then is grounded, the second switch piece is connected with a second trigger piece, the second switch piece responds to the trigger state of the second trigger piece to control the on-off of the second loop, and when the second loop is conducted, the second trigger piece turns off the second switch piece;
the second switching element is configured as a switching transistor Q2 with a collector and an emitter connected in series into the second loop, the second triggering element includes a resistor module serially disposed in the first loop, two ends of the resistor module are respectively coupled with a base and an emitter of the switching transistor Q2, the resistor module includes a plurality of first resistors disposed in parallel, and at least one of the first resistors is configured as an adjustable resistor.
Through above-mentioned technical scheme, first return circuit switches on under the normal condition, and after the electric current increases suddenly, because the partial pressure effect of resistance module for switching on triode Q2 switches on, makes the second return circuit switch on ground connection from this, and first return circuit disconnection, and then protects the equipment end. Because the resistance module adopts a plurality of resistances to set up in parallel for the electric current through the resistance module is shunted by a plurality of first resistances, and when one of them first resistance is damaged in the sudden increase of electric current, all the other first resistances still can normally work, and when the electric current resumes normally, above-mentioned current-limiting protection circuit still can play the effect of current-limiting.
Further, the first switch element is configured as a PMOS transistor, a source electrode of the PMOS transistor is electrically connected to the power supply end through the resistor module, a gate electrode of the PMOS transistor is grounded, and a drain electrode of the PMOS transistor is electrically connected to the device end interface;
the first trigger is configured as a trigger resistor R5, and the trigger resistor R5 is connected in parallel with the source and the gate of the PMOS transistor.
Through above-mentioned technical scheme, when the electric current is normal, the electric current is through first return circuit transmission, and the partial pressure effect of resistance module is not obvious this moment, and switching triode Q2 does not switch on, and trigger resistance R5 provides the turn-on voltage for the PMOS pipe this moment. When the switching transistor Q2 is turned on, the trigger resistor R5 is short-circuited, and the voltage across the trigger resistor R5 drops rapidly, so that the PMOS transistor is turned off.
Furthermore, the collector of the switching triode Q2 is connected with the gate of the PMOS transistor and then grounded through a third switching element;
the third switching element is configured as a conducting triode, the base electrode of the conducting triode is coupled with a control signal, and the collector electrode of the conducting triode and the grounding state of the grid electrode of the PMOS tube are controlled in response to the control signal.
Through the technical scheme, whether the current-limiting protection circuit can work or not can be controlled through an external control device.
Furthermore, a first voltage stabilizing diode is arranged in the first loop between the equipment end input interface and the equipment end output interface in parallel.
Through the technical scheme, the voltages at the two ends of the input and output interface of the equipment end can be stabilized.
Further, the current limiting protection circuit is further configured with:
the overcurrent detection component is configured to be used for detecting an overcurrent value of current in the first loop and outputting a detection value signal;
and the overcurrent judging component is configured to receive the detection value signal, compare the detection value signal with a reference voltage and output the control signal based on the comparison result.
Through the technical scheme, when the current value in the first loop exceeds the set value, a control signal is output immediately to control the on-off of the conduction triode, so that the first loop can be turned off when the loop current exceeds the set value.
Further, the over-current detection assembly comprises a third resistor R7 connected in series in the first loop, and a subtractor circuit connected in parallel with the third resistor R7 and arranged based on a first comparator D1, wherein the subtractor circuit collects and outputs a voltage difference value between two ends of the third resistor R7, namely the detection value signal;
the over-current determining component comprises a second comparator D2, the second comparator D2 receives the voltage difference and compares the voltage difference with the reference voltage, and the control signal is output based on the comparison result.
Through the technical scheme, when the current in the first loop is suddenly increased, the voltage difference value at two ends of the third resistor R7 is increased, the subtractor circuit collects and outputs the voltage difference value, and if the voltage difference value does not exceed the preset value of the second comparator D2, the comparator outputs a low-level signal to turn off the third switch, so that the effect of turning off the whole first loop and the whole second loop after the current is overloaded is achieved.
Further, a control unit is also configured in the overcurrent judging assembly; wherein the control unit includes:
a delay module configured to be coupled to the comparison output terminal of the second comparator D2, receive and respond to the output result of the second comparator D2, and output a delay signal with a set duration;
the over-current value calculating module is configured to be electrically connected with the output end of the subtracter circuit, receive the voltage difference value of the subtracter circuit, compare the voltage difference value with a set value and output a difference value signal;
the integral operation module is configured to be in signal connection with the delay module and the over-current value calculation module, receive the difference signal and the delay signal, integrate the difference signal within a set delay time and output an integral operation value;
and the turn-off triggering module is configured to be in signal connection with the integral operation module, receive the integral operation value, compare the integral operation value with a set triggering value, and output a control signal to turn off the conducting triode if the integral operation value reaches the set triggering value.
Through the technical scheme, a time delay judgment function is introduced, the second loop is prevented from being turned off by mistake, when the current of the first loop continuously exceeds a set value in a set time period, the first loop is turned off, and the stability and the safety of the whole current limiting circuit can be ensured.
Further, a pull-up resistor R3 is arranged between the resistor module and a power supply end in series;
the output interface of the equipment end is serially connected with a pull-down resistor R4 and then grounded;
a capacitor is connected in series between one end of the pull-up resistor R3 far away from the power supply end and one end of the pull-down resistor R4 close to the output interface of the equipment end;
the positive electrode of the capacitor is connected with the pull-up resistor R3, and the negative electrode of the capacitor is connected with the pull-down resistor R4.
Through the technical scheme, after the current changes suddenly, the voltage in the circuit also changes correspondingly, and the influence of the change on the circuit can be buffered by arranging the capacitor.
Further, the capacitor comprises a plurality of sub-capacitors arranged in parallel.
Through the technical scheme, because the large current is instantaneous, the parallel capacitors are beneficial to the rapid charge and discharge of the capacitors, and the rapid response of the capacitors is realized.
Furthermore, the conducting triode is configured as a PNP type triode, a collector of the conducting triode is connected with a collector of the switching triode Q2 and a gate of the PMOS transistor, and an emitter of the conducting triode is connected in series with a second resistor R6 and then grounded;
the sum of the resistance values of the pull-up resistor R3 and the second resistor R6 is not more than the resistance value of the trigger resistor R5.
Through the technical scheme, the continuous stable conduction of the first loop can be ensured.
Further, the first trigger is configured as a second zener diode, and a zener value of the second zener diode is not less than the turn-on voltage of the PMOS transistor.
Through above-mentioned technical scheme, can promote the stability that the PMOS pipe switched on.
Furthermore, the resistance value of the resistor module is 0.5-2.0 Ω, and the resistance values of the pull-up resistor R3 and the pull-down resistor R4 are not lower than 3K Ω.
Based on the current-limiting protection circuit, the invention also provides a control method of the current-limiting protection circuit, based on the current-limiting protection circuit, comprising the following steps:
selecting a current limiting mode, wherein the current limiting mode comprises the steps of switching off the first loop after the current exceeds a set value and then immediately recovering to be conducted; or the first loop and the second loop are turned off after the current exceeds a set value;
if the selected mode is to turn off the first loop and the second loop after the current exceeds a set value, the steps further include:
collecting the current value in the first loop, and judging whether the current value exceeds a set value;
if the current value exceeds a set value, the conducting triode is turned off; or
And calculating a current difference value between the current value and a set current value, calculating a time integral value of the current difference value in a set time period, and outputting a control signal to cut off the second loop if the time integral value exceeds the set value.
Through the technical scheme, a user can select different current limiting modes according to different working conditions during initial setting, namely the first loop can be recovered immediately after being cut off or the first loop cannot be recovered after being cut off, the application range of the whole current limiting circuit is greatly expanded, in addition, the current in the first loop is sampled and judged in the current limiting process, the first loop is prevented from being cut off by mistake, and the reliability of the whole current limiting circuit is improved.
Compared with the prior art, the invention has the following beneficial effects:
(1) the resistance module with the adjustable resistance value is connected between the base electrode and the emitting electrode of the switching triode Q2, so that the upper limit value of the current limiting protection circuit can be adjusted, and the form of parallel connection of a plurality of first resistors is adopted, so that the current flow of a single first resistor is reduced, the heat productivity of the first resistor is reduced, and the stability and reliability of the circuit are ensured;
(2) the overcurrent detection assembly and the overcurrent judgment assembly are arranged in the first loop, and whether the first loop is turned off for a long time is determined based on the judgment result of the overcurrent judgment assembly, so that the application range of the whole current limiting circuit is expanded; when the current in the first loop continuously exceeds a set value in a set time period, the first loop is turned off, and the safety and the reliability of the whole current limiting circuit are improved.
Drawings
FIG. 1 is a schematic diagram of a prior art current limiting circuit;
FIG. 2 is a schematic diagram of a current limiting circuit according to a first embodiment of the present invention;
fig. 3 is a schematic structural diagram of a current limiting circuit according to a second embodiment of the present invention.
Reference numerals: 1. a power supply terminal; 2. a first switching member; 3. an equipment end input interface; 4. an equipment end output interface; 5. a first trigger; 6. a second switching member; 8. a resistance module; 9. a third switching member; 10. a first zener diode; 11. a capacitor; 12. an overcurrent detection component; 13. and an overcurrent determination component.
Detailed Description
The present invention will be described in further detail with reference to examples and drawings, but the present invention is not limited to these examples.
Example one
A current-limiting protection circuit, disposed between a power end 1 and a device end, as shown in fig. 2, mainly includes a first loop and a second loop. In the first loop, current flows to the equipment end through the power end 1, and the second loop is directly grounded, so that the influence of instantaneous large current on the equipment end is avoided.
In detail, one end of the first loop is electrically connected to the power source terminal 1, and the other end of the first loop is grounded after being sequentially connected to the first switch 2, the device terminal input interface 3, and the device terminal output interface 4. The first switch member 2 is connected with a first trigger member 5, and the first switch member 2 controls the on-off of the first circuit in response to the trigger state of the first trigger member 5.
In the present embodiment, the power source terminal 1 is configured to have a 12V dc voltage and is powered by an external power supply device. The first switch element 2 is configured as a PMOS transistor, a source electrode of the PMOS transistor is electrically connected with the power supply end 1 through the resistor module 8, a gate electrode of the PMOS transistor is grounded, and a drain electrode of the PMOS transistor is electrically connected with the device end interface. Correspondingly, the first trigger 5 is configured as a trigger resistor R5. One end of the trigger resistor R5 is electrically connected to the power supply terminal 1, the other end is grounded, and both ends are connected in parallel to the source and the gate of the PMOS transistor. In the present embodiment, the PMOS transistor may adopt SSM3J340R, the on voltage of which is Vgs = -4.0V. The resistance of the trigger resistor R5 is sufficient to meet the requirement that its own divided voltage is not lower than the on-state voltage.
In another embodiment, the first trigger device 5 may be configured as a second zener diode, and the regulated voltage of the second zener diode satisfies the conduction voltage of the PMOS transistor, so that the conduction effect is more stable than that of the trigger resistor R5.
One end of the second loop is electrically connected with the power supply end 1, the other end of the second loop is connected with the second switch part 6 and then grounded, the second switch part 6 is connected with the second trigger part, and the second switch part 6 controls the on-off of the second loop in response to the trigger state of the second trigger part. Wherein, when the second loop is conducted, the second trigger part turns off the second switch part 6.
In detail, the second switching element 6 is a switching transistor Q2 having a collector and an emitter connected in series to the second circuit, and the switching transistor Q2 is a PNP transistor whose on-state voltage is set to 5V. In detail, the emitter of the switching transistor Q2 is electrically connected to the power source terminal 1, the collector of the switching transistor Q2 is grounded, and the base of the switching transistor Q2 is coupled to the source of the PMOS transistor. The second trigger element includes a resistor module 8 serially connected in the first loop, and two ends of the resistor module 8 are respectively coupled to the base and the emitter of the switching transistor Q2. In the present embodiment, the resistance module 8 includes a plurality of first resistors arranged in parallel, wherein at least one of the first resistors is configured as an adjustable resistor.
Further, as shown in fig. 2, the collector of the switching transistor Q2 is connected to the gate of the PMOS transistor and then grounded through the third switching element 9. The third switch 9 is configured as a conducting triode, the base of the conducting triode is coupled with a control signal, and the collector of the conducting triode and the grounding state of the grid of the PMOS tube are controlled in response to the control signal. According to the technical scheme, whether the current-limiting protection circuit can work or not can be controlled through an external control device.
Furthermore, the conducting triode is configured as PNP type triode, the collector of the conducting triode is connected with the collector of the switching triode Q2 and the grid of the PMOS tube, and the emitter is grounded after being connected with a second resistor R6 in series
Based on the above scheme, when the current is normal, the current is transmitted through the first loop, the voltage division effect of the resistor module 8 is not obvious at the moment, the switching triode Q2 is not conducted, and the trigger resistor R5 provides conducting voltage for the PMOS transistor at the moment. When the switching transistor Q2 is turned on, the trigger resistor R5 is short-circuited, and the voltage across the trigger resistor R5 drops rapidly, so that the PMOS transistor is turned off. When the current in the first loop suddenly increases, the switching transistor Q2 is turned on due to the voltage division of the resistor module 8, so that the second loop is turned on and grounded. At this time, the trigger resistor R5 is short-circuited, and the PMOS transistor is turned off to disconnect the first loop, thereby protecting the device terminal. Because resistance module 8 adopts a plurality of resistances to connect in parallel and sets up for the electric current through resistance module 8 is shunted by a plurality of first resistances, and after one of them first resistance took place to damage at the electric current sudden increase, all the other first resistances still can normally work, and when the electric current recovered normal back, above-mentioned current-limiting protection circuit still can play the effect of current-limiting.
In order to stabilize the voltage at both ends of the device-side input/output interface, a first zener diode 10 is connected in parallel between the device-side input interface 3 and the device-side output interface 4 in the first loop.
In more detail, a pull-up resistor R3 is connected in series between the resistor module 8 and the power source terminal 1. The device-side output interface 4 is connected in series with a pull-down resistor R4 and then grounded. A capacitor 11 is connected in series between one end of the pull-up resistor R3 far away from the power supply end 1 and one end of the pull-down resistor R4 close to the equipment end output interface 4, the positive electrode of the capacitor 11 is connected with the pull-up resistor R3, and the negative electrode of the capacitor is connected with the pull-down resistor R4. When the current changes suddenly, the voltage in the circuit changes correspondingly, and the influence of the change on the circuit can be buffered by arranging the capacitor 11.
Preferably, the capacitor 11 comprises a plurality of sub-capacitors 11 arranged in parallel. Since a large current is instantaneously generated, the plurality of capacitors 11 connected in parallel contribute to rapid charging and discharging of the capacitors 11, and rapid response of the capacitors 11 is realized.
In order to ensure the optimal operation of the whole current-limiting protection circuit, the sum of the resistance values of the pull-up resistor R3 and the second resistor R6 is not more than the resistance value of the trigger resistor R5. In this embodiment, the resistance of the pull-up resistor R3 and the second resistor R6 is not less than 3K Ω, the resistance of the trigger resistor R5 is not less than 9K Ω, and the resistance of the resistor module 8 is 0.5-2.0 Ω, preferably 1.0 Ω.
Example two
A current-limiting protection circuit, which is different from the first embodiment in that:
the current-limiting protection circuit is also provided with an overcurrent detection component 12 and an overcurrent determination component 13.
The over-current detection component 12 is configured to detect whether the current in the first loop exceeds a set value, and output a detection value signal. The over-current determining component 13 detects the value signal and compares it with a reference voltage to output the control signal.
In detail, as shown in fig. 3, the over-current detecting assembly 12 includes a third resistor R7 connected in series in the first loop and a subtractor circuit connected in parallel with the third resistor R7 and configured based on a first comparator D1, in fig. 3, the resistor R8, the resistor R9, the resistor R10 and the resistor R11 are all set to 1K Ω, and the third resistor R7 is set to 0.5-2.0 Ω, preferably 1.0 Ω.
One end of the third resistor R7 near the device-side input interface 3 is electrically connected to the inverting input terminal of the subtractor circuit, and the other end is electrically connected to the inverting input terminal of the subtractor circuit.
The over-current determining component 13 comprises a second comparator D2, wherein a common input terminal of the second comparator D2 is coupled to the output terminal of the subtractor circuit, an inverted input terminal thereof is coupled to a reference voltage Uref, and a comparison output terminal thereof outputs the control signal.
The subtractor circuit collects and outputs a voltage difference across the third resistor R7. The difference between the output voltages of the subtractor circuit is the voltage at the junction of the non-inverting input terminal thereof and the third resistor R7 minus the voltage at the junction of the inverting input terminal thereof and the third resistor R7.
When the current in the first loop is at a normal value, the level of the same-direction input end of the second comparator D2 is not lower than the voltage at the reverse-direction input end, and the control signal is a high level signal, so that the third switching element 9 is always in a conducting state.
When the current in the first loop suddenly increases, the voltage across the third resistor R7 increases, the subtracted output decreases, the level of the equidirectional input end of the second comparator D2 is lower than the voltage at the inverse input end, and the control signal is a low level signal, so that the third switch 9 becomes an off state.
Compared with the scheme of the first embodiment, in the scheme of the first embodiment, when the current exceeds the set value, the first loop is turned off, and when the current returns to the normal value, the first loop is automatically turned on again. In the second embodiment, when the current in the first loop exceeds the set value, the first switch 2 in the first loop cannot be automatically turned on again due to the turn-off of the third switch 9, so that the first loop and the second loop are completely turned off and cannot be recovered.
In a specific embodiment, the over-current detection assembly 12 and the over-current determination assembly 13 can be selectively connected to the first circuit and/or the second circuit through a gating element, for example, a self-locking switch is disposed between the resistor R9 and the third resistor R7, and a dry battery is detachably disposed at the base of the conducting triode of the third switch element 9, so as to select the operation mode of the current-limiting protection circuit according to different usage scenarios, for example, the control of a gas valve.
Preferably, a control unit is further configured in the overcurrent determination module 13. Wherein, the control unit mainly includes: the device comprises a delay module, an overcurrent value calculation module, an integral calculation module and a turn-off trigger module.
The delay module is coupled to the comparison output of the second comparator D2, and receives and outputs a delay signal with a set duration in response to the output of the second comparator D2. It should be noted that the delay signal includes a delay trigger signal when the delay output starts and a delay termination signal output after the delay setting time length.
The over-current value calculation module is configured to be electrically connected with the output end of the subtracter circuit, receive the voltage difference value of the subtracter circuit, compare the voltage difference value with a set value and output a difference value signal. In practical applications, the over-current value calculation module may be configured as a single chip module or other control chip modules with an operation function.
The integral operation module is configured to be in signal connection with the delay module and the over-current value calculation module, receive the difference signal and the delay signal, integrate the difference signal within a set delay time, and output an integral operation value. In detail, the integral operation module may be configured as a specific integral operation circuit, and the integral operation circuit receives and responds to the delay trigger signal to start calculating the difference signal, and finally responds to the delay termination signal to end the operation, and outputs the integral operation value.
The turn-off triggering module is configured to be in signal connection with the integral operation module, receive the integral operation value and compare the integral operation value with a set triggering value, and if the integral operation value reaches the set triggering value, output a control signal and turn off the conducting triode. Similar to the overcurrent value calculation module, the shutdown trigger module may be configured in a control chip module (including a necessary AD converter), and determine a result of comparing the integral calculation value with a set trigger value based on a program set in the control chip module.
In the present invention, based on the current-limiting protection circuit in the second embodiment, the present invention further provides a control method of the current-limiting protection circuit, based on the current-limiting protection circuit, including the following steps:
selecting a current limit mode, comprising:
the first loop is turned off after the current exceeds a set value and then immediately conducted, or the first loop and the second loop are turned off after the current exceeds the set value;
if the selected mode is to turn off the first loop and the second loop after the current exceeds a set value, the steps further include:
collecting the current value in the first loop, and judging whether the current value exceeds a set value;
if the current value exceeds a set value, the conducting triode is turned off; or
And calculating a current difference value between the current value and a set current value, calculating a time integral value of the current difference value in a set time period, and outputting a control signal to cut off the second loop if the time integral value exceeds the set value.
According to the technical scheme, a user can select different current limiting modes according to different working conditions during initial setting, namely the first loop can be recovered immediately after being cut off or the first loop cannot be recovered after being cut off, the application range of the whole current limiting circuit is greatly expanded, in addition, the current in the first loop is sampled and judged in the current limiting process, the first loop is prevented from being cut off by mistake, and the reliability of the whole current limiting circuit is improved.
The above description is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments, and all technical solutions belonging to the idea of the present invention belong to the protection scope of the present invention. It should be noted that modifications and embellishments within the scope of the invention may occur to those skilled in the art without departing from the principle of the invention, and are considered to be within the scope of the invention.
Claims (10)
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| CN202010007537.6A CN111064159A (en) | 2020-01-04 | 2020-01-04 | Current-limiting protection circuit and control method thereof |
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| CN202010007537.6A CN111064159A (en) | 2020-01-04 | 2020-01-04 | Current-limiting protection circuit and control method thereof |
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| CN112737055A (en) * | 2021-01-13 | 2021-04-30 | 南昌嘉信高科技有限公司 | Charging protection circuit and electronic equipment |
| CN113691113A (en) * | 2021-08-16 | 2021-11-23 | 珠海格力电器股份有限公司 | Output protection device and method of frequency converter power supply and frequency converter |
| CN113824294A (en) * | 2021-08-31 | 2021-12-21 | 珠海格力电器股份有限公司 | Switch tube protection circuit and drive circuit |
| CN114268159A (en) * | 2022-01-19 | 2022-04-01 | 南斗六星系统集成有限公司 | High-reliability vehicle-mounted USB charging product supporting precise current-limiting control |
| CN114520502A (en) * | 2020-11-19 | 2022-05-20 | 开利公司 | A protection circuit system and electronic equipment |
| CN115133646A (en) * | 2022-09-01 | 2022-09-30 | 陕西中科天地航空模块有限公司 | Power supply path control circuit with priority |
| WO2023000355A1 (en) * | 2021-07-20 | 2023-01-26 | Tcl华星光电技术有限公司 | Current limiting circuit |
| US12132307B2 (en) * | 2021-07-20 | 2024-10-29 | Tcl China Star Optoelectronics Technology Co., Ltd. | Current limiting circuits capable of adjusting current limiting value |
| US12230956B2 (en) * | 2021-07-20 | 2025-02-18 | Tcl China Star Optoelectronics Technology Co., Ltd. | Current limiting circuits |
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| US12230956B2 (en) * | 2021-07-20 | 2025-02-18 | Tcl China Star Optoelectronics Technology Co., Ltd. | Current limiting circuits |
| CN113691113A (en) * | 2021-08-16 | 2021-11-23 | 珠海格力电器股份有限公司 | Output protection device and method of frequency converter power supply and frequency converter |
| CN113824294A (en) * | 2021-08-31 | 2021-12-21 | 珠海格力电器股份有限公司 | Switch tube protection circuit and drive circuit |
| CN114268159A (en) * | 2022-01-19 | 2022-04-01 | 南斗六星系统集成有限公司 | High-reliability vehicle-mounted USB charging product supporting precise current-limiting control |
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