Patent Application
20180013282
This application is based upon and claims priority to Chinese Patent Application No. 201610522528.4, filed on Jul. 5, 2016, the entire contents of which are incorporated herein by reference.
The present invention relates to a short-circuit-protection electronic switch, and more specifically, to an electronic switch having load over-current and short-circuit protection functions that can upgrade the existing phase angle control, PWM electronic switches, and take the places of part of the existing mechanical contact switches, relays and contactors; it belongs to the field of power electronics.
Currently, among the existing AC and DC load switch circuits, such as all types of high-, medium- and low-voltage lighting, motors, transformers, to turn-on and turn-off controls of electric heating/lighting appliances, phase angle controls and PWM controls of power modulation circuits, when the primary switch withstand higher voltage state, if the load encounters an over-current or short circuit during running or start-up, the change rate of failure voltage dv/dt and failure current di/dt remains extremely high, and ordinary electronic switches do not cope with such high instantaneous changes well so that they are easily suffered to breakdown; the use of an independent electronic protective circuit usually needs to consume some power, and it needs to have an added auxiliary power supply, that leads to a complicated structure, and cannot be used in some low-cost, ultra-low-power required and two-wire switching applications, therefore, the load over-current and short-circuit protection for these kinds of high-voltage appliances are still currently dominated by metal fuses and mechanical circuit breakers coupled with thyristors, mechanical contact switches and mechanical contact relays; such traditional electronic components, mechanical switches, and circuit breakers have shortcomings such as high cost, low precision and slow actions, the mechanical contacts cause electric arcs and sparks during operating, which not only results to decreased safety, but also produces strong electromagnetic interference to affect surrounding electronic devices; meanwhile, the sparks and arcs also burn the contacts gradually, thus reducing the service life of the switches, furthermore, when the load encounters an over-current or short circuit, the traditional fuses and circuit breakers may be failure to operate by great errors of protective parameters of electromagnetic actuators because of aging, so it may not meet the requirements of safety, low cost, networking and intelligence switching for AC and DC load control of future social.
To solve the technical problem above, the present invention provides a short-circuit-protection electronic switch which is series connection to the load and directly controls the load to implement start-up, turn-on and turn-off operations; when the current sense unit detects the load start-up or load current is higher than the preset threshold value during the load turn-on or start-up process, the internal cut-off-type positive feedback protective trigger circuit is activated, to cut off the current series connection to the load to achieve the load over-current and short-circuit protection. The electronic switch can be directly used as a load switch, and it provides load over-current and short-circuit protection functions; it features high protection precision and fast response, it can implement reset load failure protection as well as one-time restart or multiple restart functions, and it can be made as components such as universal short-circuit-protection electronic switch, two-wire short-circuit-protection electronic switch, short-circuit-protection electronic relay, short-circuit-protection phase angle control electronic switch and short-circuit-protection PWM electronic switch.
To achieve the above purposes, the present invention adopts the following technical solution.
The present invention provides a short-circuit-protection electronic switch applied to DC circuits, comprising a DC primary switch component, a gate current limiting component, a voltage follower component, a positive feedback gate component, a feedback setting component, a DC current sense unit and a control unit.
The input of the said DC primary switch component is connected to the output of the said positive feedback gate component and one port of the said gate current limiting component, and the other port of the said gate current limiting component is connected to the gate control input (Gate), the output of the said DC primary switch component is connected to the first DC series connection output (PD1) and simultaneously connected to the output of the voltage follower component, the common of the said DC primary switch component is connected to the input of the said DC current sense unit, the common of the said DC current sense unit is connected to the second DC series connection output (PD2) and simultaneously connected to the control ground, the output of the said DC current sense unit is connected to the input of the said DC primary switch component, one port of the gate current limiting component and the output of the positive feedback gate component, the common of the said positive feedback gate component is connected to the control ground, the input of the said voltage follower component is connected to a stable bias voltage source, the common of the said voltage follower component is connected to one port of the feedback setting component, and the other port of the said feedback setting component is connected to the input of the said positive feedback gate component and simultaneously connected to the start-up output (ST) of the said control unit.
The power supply input of the said control unit is connected to the control power supply VCC; its second input is connected to the gate control input (Gate), while its first input is connected to the common of the said voltage follower; the said control unit has an internal inhibit output (Inhibit1) and an external inhibit output (Inhibit2); the internal inhibit output Inhibit1 is connected to the output of the said positive feedback gate component while the external inhibit output (Inhibit2) is connected to the inhibit input of the external gate driver.
When the said DC primary switch component is in the OFF state, input the first control voltage or the first control current to the gate control input (Gate), if at this time the load current going through the DC load (DL) is lower than the protective preset value, the control unit output the start-up signal to the input of the said positive feedback gate component via the start-up output (ST) to implement load start-up and turn-on operations, in this case the said DC primary switch unit will be shifted from cut-off state to amplification state then access to saturated conduction state, so that the said DC primary switch component is in the ON state.
When the said DC primary switch component is in the ON state, if input the second switch control voltage or the second control current to the gate control input (Gate), the said DC primary switch component will be shifted from saturated conduction state to amplification state and eventually access to cut-off state, so the said DC primary switch component is in the OFF state.
When the said DC current sense unit detects that the load current is higher than the protective preset value, the cut-off-type positive feedback protective trigger circuit is triggered, thus turning off the said DC primary switch component.
Preferably, the said DC primary switch component and the said positive feedback gate component form the said cut-off-type positive feedback protective trigger circuit; the feedback path of the said cut-off-type positive feedback protective trigger circuit goes through the said voltage follower component, and the said DC primary switch component is a part of the said cut-off-type positive feedback protective trigger circuit.
Preferably, the feedback path of the said cut-off-type positive feedback protective trigger circuit successively goes through: the output of the said DC primary switch component to the output of the said voltage follower component to the common of the said voltage follower component to the feedback setting component to the input of the said positive feedback gate component to the output of the said positive feedback gate component to the input of the said DC primary switch component.
Preferably, the output follower voltage (VR) of the said voltage follower component outputs a stable voltage that does not depend on an external power supply to support low-power devices when the said DC primary switch component is in the OFF state.
Preferably, functions of the control unit comprise: load failure signal and protection function, restart function after load failure, control power supply VCC low voltage lockout function UVLO, switch overheat signal and protection function, and primary switch component failure signal function;
Specific functions of the control unit comprise: the first input of the said control unit receives the follower output voltage value (VR) of the said voltage follower component, and the second input receives the control voltage or current value of the said gate control input (Gate); if the said output follower voltage (VR) of the said voltage follower component and the measured value of the gate control input (Gate) show that the said DC primary switch component is substantially in the load failure OFF state, the said control unit will output the load failure signal according to the logical result, and meanwhile it can implement or not implement restart after load failure to the input of the said positive feedback gate component via the output (ST), according to the preset requirements;
The first input of the said control unit receives the follower output voltage value VR, and the second input receives the control voltage or current value of the gate control input (Gate); if the output follower voltage (VR) of the said voltage follower component and the measured value of the gate control input (Gate) show that the said DC primary switch component is substantially in the load failure OFF state, the said control unit will output the primary switch component failure signal according to the logical result;
Methods of implementing the restart after load failure: when the said control unit detects that a load failure occurs, if the preset program contains the requirement of the restart after load failure function and the gate control input (Gate) still maintains the first control voltage or the first control current, it will implement restart after load failure function a short while after the load failure occurs; the detailed restart process is, the output (ST) gives an instantaneous pulse signal to the input of the said positive feedback gate component, driving the positive feedback gate component secede the saturated conduction state, and the said DC primary switch component secede the cut-off state; if at this time the start-up or running current of the series connection DC load (DL) is lower than the protective preset value, the said cut-off-type positive feedback protective trigger circuit will drive the said DC primary switch component access to the saturated conduction state, so as to ensure the normal start-up and turn-on of the load; if at this time the start-up or running current of the series connection DC load (DL) is higher than the protective preset value, the said cut-off-type positive feedback protective trigger circuit will drive the said DC primary switch component secede the cut-off state and access to the conduction state, and then quickly return back to the cut-off state again.
It can implement one-time restart or multiple restarts or stop restarting upon many times of invalid restarts after load failure, according to the power tolerance of the said DC primary switch component.
The control unit senses the temperature of the said DC primary switch component by detecting the sensing value of the temperature sensor close to the DC primary switch component; if the sensed temperature is higher than the overheat preset value, the control unit will output the primary switch component overheat signal but not turn off the said DC primary switch component, or turn off the said DC primary switch component via the internal inhibit port (Inhibit1) and meanwhile output the primary switch component overheat signal.
The present invention provides a short-circuit-protection electronic switch applied to AC circuits, comprising an AC primary switch component, a gate current limiting component, a voltage follower component, a positive feedback gate component, a feedback setting component, an AC current sense unit and a control unit.
The input of the said AC primary switch component is connected to the said output of the positive feedback gate component and one port of the said gate current limiting component, and the other port of the said gate current limiting component is connected to the gate control input (Gate), the first AC output of the said AC primary switch component is connected to the first series connection AC output port, the rectified voltage output of the said AC primary switch component is connected to the output of the said voltage follower component, the first common of the said AC primary switch component is connected to the first input of the said AC current sense unit, the second common of the said AC current sense unit is connected to the second input of the said AC current sense unit, the first common or the second common of the said AC primary switch component is connected to the control ground, the second AC output of the said AC primary switch component is connected to the second AC series connection output (PA2), the output of the said AC current sense unit is connected to the input of the said AC primary switch component, one port of the said gate current limiting component and the output of the said positive feedback gate component, the common of the said positive feedback gate component is connected to the control ground, the input of the said voltage follower component is connected to a stable bias voltage source, the common of the said voltage follower component is connected to one port of the said feedback setting component, and the other port of the said feedback setting component is connected to the input of the said positive feedback gate component and simultaneously connected to the start-up output port (ST) of the said control unit.
The power supply input of the said control unit is connected to the control power supply (VCC); its second input is connected to the gate control input (Gate), while its first input is connected to the common of the said voltage follower; the control unit has an internal inhibit output (Inhibit1) and an external inhibit output (Inhibit2); the internal inhibit output (Inhibit1) is connected to the output of the said positive feedback gate component, while the external inhibit output (Inhibit2) is connected to the inhibit input of the external gate driver.
When the AC primary switch component is in the OFF state, input the first control voltage or the first control current in the gate control input (Gate), if at this time the load current going through the AC load (AL) is lower than the protective preset value, the said control unit will output the start-up signal to the input of the positive feedback gate component via the start-up output port (ST) to implement load start-up and turn-on operations, in this case the AC primary switch component will be shifted from a cut-off state to amplification state and then access to saturated conduction state, so that the said AC primary switch component is in the ON state.
When the said AC primary switch component is in the ON state, if inputs the second switch control voltage or the second control current in the gate control input (Gate), the said AC primary switch component will be shifted from into saturated conduction state to amplification state and eventually access to a cut-off area, so that the said AC primary switch component is in the OFF state.
When the said AC current sense unit detects that the load current is higher than the protective preset value, the said cut-off-type positive feedback protective trigger circuit is triggered, thus turning off the said AC primary switch component.
Preferably, the said AC primary switch component and the said positive feedback gate component form the said cut-off-type positive feedback protective trigger circuit; the feedback path of the said cut-off-type positive feedback protective trigger circuit goes through the said voltage follower component, and the said AC primary switch component is a part of the said cut-off-type positive feedback protective trigger circuit.
Preferably, the feedback path of the said cut-off-type positive feedback protective trigger circuit successively goes through: the rectified voltage output of the said AC primary switch component to the output of the said voltage follower component to the common of the said voltage follower component to the said feedback setting component to the input of the said positive feedback gate component to the output of the said positive feedback gate component to the input of the said AC primary switch component.
Preferably, the output follower voltage of the said voltage follower component outputs a stable voltage that does not depend on an external power supply to support low-power devices when the said AC primary switch component is in the OFF state.
Preferably, functions of the control unit comprise: load failure signal and protection function, restart after load failure function, control power supply low voltage lockout function UVLO, switch overheat signal and protection function, and primary switch component failure signal function.
Specific functions of the said control unit comprise: the first input of the said control unit receives the follower output voltage value (VR) of the said voltage follower component, and the second input receives the control voltage or current value of the gate control input (Gate); if the output follower voltage (VR) of the said voltage follower component and the measured value of the gate control input (Gate) show that the said DC primary switch component is substantially in the load failure OFF state, the said control unit will output the load failure signal according to the logical result, and meanwhile it can implement or not implement restart after load failure function to the input of the said positive feedback gate component via the output (ST), according to the preset requirements.
The first input of the said control unit receives the follower output voltage value VR of the said voltage follower component, and the second input receives the control voltage or current value of the gate control input (Gate); if the output follower voltage VR of the said voltage follower component and the measured value of the gate control input (Gate) show that the said AC primary switch element is substantially in the primary switch component failure state, the control unit will output the primary switch component failure signal according to the logical result.
Methods of implementing the restart after load failure function: when the said control unit detects that a load failure occurs, if the preset program contains the requirement of the restart after load failure function and the gate control input (Gate) still maintains the first control voltage or the first control current, it will implement restart after load failure function a short while after the load failure occurs; the detailed restart process is, the output (ST) gives an instantaneous pulse signal to the input of the said positive feedback gate component driving the said positive feedback gate component secede the saturated conduction state, and the AC primary switch component secede the cut-off state; if at this time the start-up or running current of the series connection AC load (AL) is lower than the protective preset value, the said cut-off-type positive feedback protective trigger circuit will make the said AC primary switch component access to the saturated conduction state, so as to ensure the normal start-up and turn-on of the load; if at this time the start-up or running current of the series connection AC load (AL) is higher than the protective preset value, the said cut-off-type positive feedback protective trigger circuit will drive the said AC primary switch component secede the cut-off state and access to the conduction state, and then quickly return back to the cut-off state again.
It can implement after load failure restart function one-time restart or multiple restarts or stop restarting upon many times of invalid restarts, according to the power tolerance of the said AC primary switch component;
The said control unit senses the temperature of the said AC primary switch element by detecting the sensing value of the temperature sensor element close to the AC primary switch component; if the sensing temperature is higher than the overheat preset value, it will output the primary switch component overheat signal but not turn off the said AC primary switch component, or turn off the said AC primary switch component via the internal inhibit port (Inhibit1) and meanwhile output the primary switch component overheat signal.
The beneficial effects of the present invention are as below.
The said cut-off-type positive feedback protection trigger circuit constitutes a primary switch component, a voltage follower component and a positive feedback gate component. With its feedback voltage change rates dv/dt rising along with the primary voltage, it greatly improves the electronic switch's performance of resisting the high voltage load short circuit, and meanwhile significantly reduces the control power consumption of the protective circuit. Featuring an extremely high response speed, it can be made as a direct load short-circuit-protection high-voltage electronic switch applied to all types of high-, medium- and low-voltage lighting, motors, transformers, turn-on and turn-off control of electric heating/lighting appliances, phase angle control and PWM control of power modulation circuits, and take part of the existing mechanical contact switches, relays and contactors.
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The invention is further detailed in combination with the embodiments as follows.
This embodiment provides a short-circuit-protection electronic switch applied to DC circuits, as shown in
The input of the DC primary switch component 10 is connected to the output of the positive feedback gate component 30 and one port of the gate current limiting component 14, and simultaneously goes through a surge absorbing component 11 to connect the control ground, and the other port of the gate current limiting component 14 is connected to the gate control input Gate, the output of the DC primary switch component 10 is connected to the first DC serial connect output PD1 and simultaneously connected to the output of the voltage follower component 20, the common of the DC primary switch component 10 is connected to the input of the DC current sense unit 40, the common of the DC current sense unit 40 is connected to the second DC serial connect output PD2 and simultaneously connected to the control ground, the output of the DC current sense unit 40 is connected to the input of the DC primary switch component 10, one port of the gate current limiting component 14 and the output of the positive feedback gate component 30, the common of the positive feedback gate component 30 is connected to the control ground, the input of the voltage follower component 20 is connected to a stable bias voltage source, the common of the voltage follower component 20 outputs the follower voltage VR and goes through the voltage follower current limiting component 24 to connect one port of the diode 23, and the other port of the diode 23 is connected to the follower power supply output VS, the common of the voltage follower component 20 is connected to one port of the feedback setting component 25, and the other port of the feedback setting component 25 is connected to the input of the positive feedback gate component 30 and simultaneously connected to the start-up output ST of the control unit 50.
The power supply input of the control unit 50 is connected to the control power supply VCC; its second input 520 is connected to the gate control input Gate, while its first input 510 is connected to the common of the voltage follower; the control unit 50 has an internal inhibit output Inhibit1 and an external inhibit output end Inhibit2; the internal inhibit output Inhibit1 is connected to the output of the positive feedback gate component 30, while the external inhibit output Inhibit2 is connected to the inhibit input of the external gate driver.
When the DC primary switch component 10 is in the OFF state, input the first control voltage or the first control current in the gate control input Gate, if at this time the load current going through the DC load DL is lower than the protective preset value, the control unit 50 will output the start-up signal to the input of the positive feedback gate component 30 via the start-up output ST to implement load start-up and turn-on operations, in this case the DC primary switch component 10 will be shifted from a cut-off state to amplification state and access to saturated conduction state, so that the DC primary switch component 10 is in the ON state.
When the DC primary switch component 10 is in the ON state, if it inputs the second switch control voltage or the second control current in the gate control input Gate, the DC primary switch component 10 will be shifted from saturated conduction state to amplification state and eventually access to cut-off state, so that the DC primary switch component 10 is in the OFF state.
When the DC current sense unit 40 detects that the load current is higher than the protective preset value, the cut-off-type positive feedback protective trigger circuit is triggered, thus turning off the DC primary switch component 10.
The DC primary switch component 10 and the positive feedback gate component 30 form a cut-off-type positive feedback protective trigger circuit; the feedback path of the cut-off-type positive feedback protective trigger circuit goes through the voltage follower component 20, and the DC primary switch component 10 is a part of the cut-off-type positive feedback protective trigger circuit.
The feedback path of the cut-off-type positive feedback protective trigger circuit successively goes through: the output of the DC primary switch component 10 to the voltage follower current limiting component 24 to the output of the voltage follower component 20 to the common of the voltage follower 20 to the feedback setting component 25 to the input of the positive feedback gate component 30 to the output of the positive feedback gate component 30 to the input of the DC primary switch component 10.
The output follower voltage VR of the voltage follower component 20 outputs a stable voltage that does not depend on an external power supply to support low-power devices when the DC primary switch component is in the OFF state.
Functions of the control unit 50 comprise: load failure signal and protection function, post-load failure restart function, low voltage lockout function UVLO of control power supply VCC, switch overheat signal and protection function, and primary switch component failure signal function.
Specific functions of the control unit 50 comprise: the first input 510 of the control unit 50 receives the follower output voltage value VR of the voltage follower component 20, and the second input end 520 receives the control voltage or current value of the gate control input Gate; if the output follower voltage VR of the voltage follower component 20 and the measured value of the gate control input Gate show that the DC primary switch component 10 is substantially in the load failure OFF state, the control unit 50 will output the load failure signal according to the logical result, and meanwhile it can implement or not implement after load failure function at the input of the positive feedback gate component 30 via the output ST, according to the preset requirements.
The first input 510 of the control unit 50 receives the follower output voltage value VR, and the second input 520 receives the control voltage or current value of the gate control input Gate; if the output follower voltage VR of the voltage follower component 20 and the measured value of the gate control input Gate show that the DC primary switch component 10 is substantially in the load failure OFF state, the control unit 50 will output the primary switch component failure signal according to the logical result.
Methods of implementing the restart after load failure function: when the control unit 50 detects that a load failure occurs, if the preset program contains the requirement of the restart after load failure function and the gate control input Gate still maintains the first control voltage or the first control current, it will implement post-load failure restart after load failure function a short while after the load failure occurs; the detailed restart process is, the output ST gives an instantaneous pulse signal to the input of the positive feedback gate component 30, driving the positive feedback gate component 30 secede the saturated conduction state, and the DC primary switch component 10 secede the cut-off state; if at this time the start-up or running current of the serial connect DC load DL is lower than the protective preset value, the cut-off-type positive feedback protective trigger circuit will drive the DC primary switch component 10 access to the saturated conduction state, so as to ensure the normal start-up and turn-on of the load; if at this time the start-up or running current of the serial connect DC load DL is higher than the protective preset value, the cut-off-type positive feedback protective trigger circuit will drive the DC primary switch component 10 secede the cut-off state and access to the conduction state, and then quickly return back to the cut-off state again.
It can implement restart after load failure function one-time restart or multiple restarts or stop restarting upon many times of invalid restarts, according to the power tolerance of the DC primary switch component 10.
The control unit 50 senses the temperature of the DC primary switch component 10 by detecting the sensing value of the temperature sensor component close to the DC primary switch component 10; if the sensing temperature is higher than the overheat preset value, the control unit 50 will output the primary switch component overheat signal but not turn off the DC primary switch component 10, or turn off the DC primary switch component 10 via the internal inhibit Inhibit1 and meanwhile output the primary switch component overheat signal.
Specific action processes of the cut-off-type positive feedback protective trigger circuit are as follows.
In the case that the DC load DL is higher than the protective preset value, when the DC primary switch component 10 is shifted from a cut-off area to saturated conduction state through amplification state or the primary switch component 10 has been in a normal ON state of saturated conduction, the cut-off-type positive feedback protective trigger circuit receives an out-of-limit signal from the DC current sense unit 40, thus triggering a protective action; in the initial stage of the protective action, by the way that the output of the DC current sense unit 40 controls the load current between the output and the common of the DC primary switch component 10, the DC primary switch component 10 is shifted from saturated conduction state to amplification state; the state transition triggers an increase in absolute value of the voltage between output ends of the DC primary switch component 10, and the increase in absolute value of the voltage goes through the output 120 of the DC primary switch component 10 to access to the voltage follower current limiting component 24 and then access to the input of the voltage follower access to 20; as the voltage follower bias input VB exists stably, and the input and the common of the voltage follower access to 20 are in a conduction state, the increase in the absolute value of the voltage then goes through the output of the voltage follower component 20 to access to the feedback setting component 25 and then access to the input of the positive feedback gate access to 30, thus driving the output of the positive feedback gate component 30 further control the absolute value of the voltage between the output and the common of the DC primary switch component 10 which further increases; the further increase once again goes through the output of the DC primary switch component 10, the voltage follower current limiting component 24, the voltage follower component 20, the feedback setting component 25 and the positive feedback gate component 30 and then access toes the input of the DC primary switch component 10, thus triggering a further increase in the absolute value of the voltage between the output and the common of the DC primary switch component 10; it repeats the process and eventually drives the DC primary switch component 10 quickly access to the cut-off state from the saturated conduction state.
Preferably, as shown in
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This embodiment provides a short-circuit-protection electronic switch applied to AC circuits, as shown in
The input of the AC primary switch component 1A is connected to the output of the positive feedback gate component 30 and one port of the gate current limiting component 14, and simultaneously goes through a surge absorbing component 11 to connect the control ground, and the other port of the gate current limiting component 14 is connected to the gate control input Gate;
The first AC output 12A of the AC primary switch component 1A is connected to the first serial connect AC output PA1, and the rectified voltage output (170) of the AC primary switch component 1A is connected to the output of the voltage follower component 20.
The first common 150 of the AC primary switch component 1A is connected to the third input 41A of the AC current sense unit 4A, the second common 160 of the AC current sense unit 1A is connected to the fourth input 43A of the AC current sense unit 4A, the first common 150 or the second common 160 of the AC primary switch component 1A is connected to the control ground, the second AC output 13A of the AC primary switch component 1A is connected to the second AC serial connect output PA2, the output end of the AC current sense unit 4A is connected to the input of the AC primary switch component 1A, one port of the gate current limiting component 14 and the output of the positive feedback gate component 30, the common of the positive feedback gate component 30 is connected to the control ground, the input of the voltage follower component 20 is connected to a stable bias voltage source, the common of the voltage follower component 20 outputs the follower voltage VR and goes through the voltage follower current limiting component 24 to connect one port of the diode 23, and the other port of the diode 23 is connected to the follower power supply output VS, the common of the voltage follower component 20 is connected to one of the feedback setting component 25, and the other port of the feedback setting component 25 is connected to the input of the positive feedback gate component 30 and simultaneously connected to the start-up output ST of the control unit 50.
The power supply input of the control unit 50 is connected to the control power supply VCC; its second input 520 is connected to the gate control input Gate and simultaneously connected to the other port of the gate current limiting component 14, while its first input 510 is connected to the common of the voltage follower 20; the control unit 50 has an internal inhibit output Inhibit1 and an external inhibit output Inhibit2; the internal inhibit output Inhibit1 is connected to the output of the positive feedback gate component 30, while the external inhibit output Inhibit2 is connected to the inhibit input of the external gate driver.
When the AC primary switch component 1A is in the OFF state, input the first control voltage or the first control current in the gate control input Gate, if at this time the load current going through the AC load AL is lower than the protective preset value, the control unit 50 will output the start-up signal to the input of the positive feedback gate component 30 via the start-up output ST to conduct load start-up and turn-on operations, in this case the AC primary switch component 1A will be shifted from a cut-off state to amplification state and then access to saturated conduction state, so that the AC primary switch component 1A is in the ON state.
When the AC primary switch component 1A is in the ON state, if it inputs the second switch control voltage or the second control current in the gate control input Gate, the AC primary switch component 1A will be shifted from saturated conduction state to amplification state and eventually access to cut-off state, so that the AC primary switch component 1A is in the OFF state.
When the AC current sense unit 4A detects that the load current is higher than the protective preset value, the cut-off-type positive feedback protective trigger circuit is triggered, thus turning off the AC primary switch component 1A.
The AC primary switch component 1A and the positive feedback gate component 30 form a cut-off-type positive feedback protective trigger circuit; the feedback path of the cut-off-type positive feedback protective trigger circuit goes through the voltage follower component 20, and the AC primary switch component 1A is a part of the cut-off-type positive feedback circuit.
The feedback path of the cut-off-type positive feedback protective trigger circuit successively goes through: the rectified voltage output 170 of the AC primary switch component 1A to the output of the voltage follower component 20 to the common of the voltage follower component 20 to the feedback setting component 25 to the input of the positive feedback gate component 30 to the output of the positive feedback gate component 30 to the input of the AC primary switch component 1A.
The output follower voltage VR of the voltage follower component 20 outputs a stable voltage that does not depend on an external power supply to support low-power devices when the AC primary switch component is in the OFF state.
Functions of the control unit 50 comprise: load failure signal and protection function, control power supply VCC low voltage lockout function ULVO, switch overheat signal and protection function, and primary switch component failure signal function.
Specific functions of the control unit 50 comprise: the first input 510 of the control unit 50 receives the follower output voltage value VR of the voltage follower component 20, the second input 520 receives the control voltage or current value of the gate control input Gate; if the output follower voltage VR of the voltage follower component 20 and the measured value of the gate control input Gate show that the AC primary switch component 1A is substantially in the load failure OFF state, the control unit 50 will output the load failure signal according to the logical result, and meanwhile it can implement or not implement restart after load failure to the input of the positive feedback gate component 30 via the output ST, according to the preset requirements.
The first input 510 of the control unit 50 receives the follower output voltage value VR, the second input 520 receives the control voltage or current value of the gate control input end Gate; if the output follower voltage VR of the voltage follower component 20 and the measured value of the gate control input Gate show that the DC primary switch component 1A is substantially in the load failure OFF state, the control unit 50 will output the primary switch component failure signal according to the logical result.
Methods of implementing the restart after load failure: when the control unit 50 detects that a load failure occurs, if the preset program contains the requirement of the restart after load failure function, it will implement restart after load failure function a short while after the load failure occurs; the detailed restart process is, the output ST gives an instantaneous pulse signal to the input of the positive feedback gate component 30, driving the positive feedback gate component 30 secede the saturated conduction state, and the AC primary switch component 1A secede the cut-off state; if at this time the start-up or running current of the serial connect AC load is lower than the protective preset value, the cut-off-type positive feedback protective trigger circuit will drive the AC primary switch component 1A enter the saturated conduction state, so as to ensure the normal start-up and turn-on of the load; if at this time the start-up or running current of the serial connect AC load AL is higher than the protective preset value, the cut-off-type positive feedback protective trigger circuit will drive the AC primary switch component 1A secede the cut-off state and access to the conduction state, and then quickly return back to the cut-off state again;
It can implement post-load failure one-time restart or multiple restarts or stop restarting upon many times of invalid restarts, according to the power tolerance of the AC primary switch component 1A.
The control unit 50 senses the temperature of the AC primary switch component 1A by detecting the sensing value of the temperature sensor component close to the AC primary switch component 1A; if the sensing temperature is higher than the overheat preset value, it will output the primary switch component overheat signal but not turn off the AC primary switch component 1A, or turn off the AC primary switch component 1A via the internal inhibit Inhibit1 and meanwhile output the primary switch component overheat signal.
Specific action processes of the cut-off-type positive feedback protective trigger circuit are as follows.
In the case that the AC load AL is higher than the preset value, when the AC primary switch component 1A is shifted from a cut-off state to saturated conduction state through amplification state, or the primary switch component 1A has been in a normal ON state of saturated conduction, the cut-off-type positive feedback protective trigger circuit receives an out-of-limit signal from the AC current sense unit 4A, thus triggering a protective action; in the initial stage of the protective action, by the way that the output 42A of the AC current sense unit 4A controls the load current between the first AC output 12A and the second AC output 13A of the AC primary switch component 1A, the AC primary switch component 1A is shifted from saturated conduction state to amplification state; the state transition triggers an increase in absolute value of the voltage between the first AC output 12A and the second AC output 13A of the AC primary switch component 1A, and the increase in absolute value of the voltage goes through the diode 16 and diode 17 to access to the voltage follower current limiting component 24 and then access to the output 220 of the voltage follower component 20; as the bias voltage VB of the input 210 exists, and the output 220 and the common 230 of the voltage follower component 20 are in conduction state, the increase in the absolute value of the voltage then goes through the common 230 of the voltage follower component 20 to reach the feedback setting component 25 and then access to the input 310 of the positive feedback gate component 30, thus driving the output 320 of the positive feedback gate component 30 further control the absolute value of the voltage between the first AC output 120 and the second AC output 130 of the AC switch component 1A which further increases; the further increase in the absolute value of the voltage once again goes through the diode 16 and diode 17 of the AC primary switch component 1A, the voltage follower current limiting component 24, the voltage follower component 20, the feedback setting component 25 and the positive feedback gate component 30 and then access toes the input 11A of the AC primary switch component 1A, thus triggering a further increase in the absolute value of the voltage between AC outputs of the AC primary switch component; it repeats the process and eventually drives the AC primary switch component 1A quickly access to the cut-off state from the saturated conduction state.
Preferably, as shown in
Preferably, as shown in
Preferably, as shown in
Preferably,
Taking into account the possible emergence of an extreme situation, such as damage or overheat protection action of the primary switching component, the short-circuit-protection electronic switch also has a primary switch component failure signal output Switch Failure, which can be used to control a breaker with mechanical contact cut-off function, an electromagnetic relay, a contact or a magnetic latching relay, and a contact so as to implement a backup safety conversion upon failure of the main electronic switch.
Preferably,
Taking into account the possible emergence of an extreme situation, such as damage or overheat protection action of the primary switching component, the short-circuit-protection electronic switch also has a primary switch component failure signal output Switch Failure, which can be used to control a breaker with mechanical contact cut-off function, an electromagnetic relay, a contact or a magnetic latching relay, and a contact so as to implement a backup safety conversion upon failure of the main electronic switch.
Preferably,
In some special cases, if the power of the serial connect load is large enough, it can use the passive output coupler featuring optoelectronic isolation 63 to form an electronic relay with internal power supply, based on the two-wire switch control as shown in
Taking into account the possible emergence of an extreme situation, such as damage or overheat protection action of the primary switching component, the short-circuit-protection electronic switch also has a primary switch component failure signal output Switch Failure, which can be used to control a breaker with mechanical cut-off function, an electromagnetic relay, a contact or a magnetic latching relay, and a contact so as to implement a backup safety conversion upon failure of the main electronic switch.
Preferably,
The present invention provides a short-circuit-protection electronic switch which is serial connect to the load and directly controls the load to conduct start-up, turn-on and turn-off operations; when the current sense unit detects that the load start-up or running current is higher than the preset threshold value during the load turn-on or start-up process, the internal cut-off-type positive feedback protective trigger circuit is activated, so as to cut off the current serial connect to the load to implement the load over-current and short-circuit protection. The electronic switch can be directly used as a load switch, and it is provided with load over-current and protection function, and can constitute components such as a universal short-circuit-protection electronic switch, two-wire short-circuit-protection electronic switch, short-circuit-protection electronic relay and short-circuit-protection phase angle control or PWM electronic switch.
Obviously, the above embodiments are only examples given for a clear description, and not intended to limit the embodiments. Those skilled in this art can make other forms of modifications and variations based on the description given above. There is no need and no way to give any other examples for all embodiments. All the obvious modifications and variations based on the solutions herein should be covered in the protection scope of the Claims of the present invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201610522528.4 | Jul 2016 | CN | national |
