Summary of the invention
The application innovatively proposes one and utilizes entire hardware control, i.e. the power-off protection control device of pure analog circuit realization.The power-off protection control device of this innovation is with low cost, makes simple and has high reliability.Under the protection of the power-off protection control device of this innovation, if switched on power time switch is in locking, its load controlled (as electric tool) does not work, and need to reclose switch, this load just can be started working.
According to an aspect of the present invention, provide a kind of power-off protection control device, itself and power input, mechanically controlled switch, electrical load loop in series, described device comprises the first capacitor charging circuit, difference of injection time control circuit, second capacitor charging circuit, controllable silicon and circuits for triggering thereof, two main terminals of the bidirectional triode thyristor in wherein said controllable silicon and circuits for triggering thereof are connected in described loop, and described first capacitor charging circuit is connected on the two ends of described power input, to charge to the first electric capacity in described first capacitor charging circuit, described second capacitor charging circuit be configured in response to the high-voltage value on described first electric capacity and described mechanically controlled switch connection by the second capacitor charging being coupled to the control pole of described bidirectional triode thyristor to be enough to trigger described bidirectional triode thyristor high-voltage value and in response to the shutoff of described mechanically controlled switch and/or described first electric capacity low voltage value not by described second capacitor charging to described high-voltage value, described difference of injection time control circuit be configured in response to described mechanically controlled switch first connect and the rear power supply of described power input is discharged to described first electric capacity and rear connection in response to first power supply and the described mechanically controlled switch of described power input is not discharged to described first electric capacity, described controllable silicon and circuits for triggering thereof are triggered and bidirectional triode thyristor described in conducting in response to the described high-voltage value of described second electric capacity.
According to preferred embodiment, described second capacitor charging circuit comprises transistor seconds switch, and described first electric capacity is coupled in the control pole of described transistor seconds switch; Described difference of injection time control circuit comprises the first transistor switch, and the control pole of described the first transistor switch is capacitively coupled to described mechanically controlled switch via resistor and second.
According to preferred embodiment, between the control pole of described first electric capacity and described transistor seconds switch, be in series with a diode.
According to preferred embodiment, in described first capacitor charging circuit, be in series with a diode.
According to preferred embodiment, described first and second transistor switches are implemented respectively by the one in various types of triode, field effect transistor and controllable silicon.
According to a second aspect of the invention, provide a kind of power-off protection control circuit, itself and power input, mechanically controlled switch, electrical load loop in series, described main circuit will comprise following element: the first transistor switch, transistor seconds switch, the first capacitor, the second capacitor and bidirectional triode thyristor, two main terminals of wherein said bidirectional triode thyristor are series in described loop, and the series circuit that described first capacitor and the first resistor are formed is connected to the two ends of described power input; The first end of described second capacitor is coupled to the control end of described bidirectional triode thyristor, and the second end is connected to the main terminal away from described mechanically controlled switch in described controllable silicon via described transistor seconds switch, described the first transistor switch is connected in parallel on described first capacitor two ends, the control end of described the first transistor switch is connected to the second end of described second capacitor via the second resistor, and is connected to the main terminal away from described mechanically controlled switch in described bidirectional triode thyristor via the 3rd resistor; The control end of described transistor seconds switch is connected to the contact between described first capacitor and described first resistor, and another main terminal of described the first transistor switch and another main terminal of described transistor seconds switch are all connected to the main terminal away from described mechanically controlled switch in described bidirectional triode thyristor; Be coupled to the control end of described bidirectional triode thyristor via the 4th resistor near the main terminal of described mechanically controlled switch in described bidirectional triode thyristor.
According to preferred embodiment, described first capacitor two ends are also parallel with the 5th resistor.
According to preferred embodiment, in the series circuit of described first resistor and described first capacitor, be also in series with diode.
According to preferred embodiment, between the control end and the contact between described first capacitor and described first resistor of described transistor seconds switch, be provided with diode.
According to a third aspect of the invention we, provide a kind of electric tool, described electric tool comprises according to the work for the electrical load controlled in described electric tool of above-mentioned power-off protection control device or above-mentioned power-off protection control circuit.
Above-described embodiment solves the technical problem preventing the electrical load accidental activation caused due to the unexpected connection of power supply when switch is switched on, and achieves the technique effect of the fail safe improving electrical load.
Embodiment
Term as used in this article " is connected to " expression and there is not intermediary element between two element connected.And as used in this article term " is coupled to " and represents can to exist between two elements connected or can not there is intermediary element.
Innovation thinking of the present invention is, discharge and recharge by utilizing the switching characteristic of transistor to carry out control capacitance on the basis of controllable silicon (also referred to as thyristor) circuits for triggering, achieve and silicon controlled selectivity is triggered, when realizing preventing the switch when electrical load to be in connection thus, electrical load is disconnected unexpected startup when being then switched at power supply, eliminate potential hazard thus, and user only needs to reclose switch (namely reclosing switch after closing switch) can realize restarting of electrical load.
Fig. 1 shows the functional block diagram of power-off protection apparatus according to an embodiment of the invention.Fig. 2 shows the circuit theory diagrams of power-off protection apparatus according to an embodiment of the invention.Can find out by figure; this power-off protection apparatus (indicated by the dotted line frame in Fig. 1) roughly comprise 5 parts, be specially the first capacitor charging circuit 1, difference of injection time control circuit 3, second capacitor charging circuit 4, controllable silicon and circuits for triggering 5 thereof and optional false action-proof circuit 6.Certainly this device also with mechanically controlled switch 2, electrical load 7 and for providing the power supply terminal of AC power (i.e. power input) L and N to be serially connected in loop.This electrical load 7 can be the motor in various electric tool, or other electrical load.This electric tool is such as hand-held type electric tool (as angle grinding machine, straight grinder, electric saw etc.), or desk type electric tools (as planer, grinding machine etc.).
First capacitor charging circuit 1 is configured to charge to the first electric capacity C1 in response to the power supply of power supply.This input charging circuit 1 is such as made up of the series circuit of the resistance R1 in Fig. 2 and electric capacity C1 (it is such as electrochemical capacitor).According to optional embodiment, in this input charging circuit 1, diode D1 can also be provided with.The function of diode D1 is halfwave rectifier, namely stops the negative half-wave in alternating current by the positive half wave in alternating current, or stops the positive half wave in alternating current by the negative half-wave in alternating current.The function of electric capacity C1 is filtering and stored charge, and be coupled to the control pole (optional diode D2 can be there is between the two) of transistor switch Q2 due to electric capacity C1, the large young pathbreaker of magnitude of voltage therefore on electric capacity C1 is a condition of transistor switch Q2 whether conducting.
Mechanically controlled switch 2 for be connected to electrical load 7 by the manually operated control switch of user, and can be switch with lock function.
Second capacitor charging circuit 4 is configured to the second electric capacity C2 being coupled to the control pole of controllable silicon T1 be charged in response to the high-voltage value of the first electric capacity C1 and the connection of mechanically controlled switch 2 high-voltage value that is enough to trigger bidirectional triode thyristor and the second electric capacity C2 be not charged to high-voltage value in response to the shutoff of mechanically controlled switch 2 and/or the low voltage value of the first electric capacity C1.According to preferred embodiment (as shown in Figure 2), the second capacitor charging circuit 4 is made up of current-limiting resistance R4, the second electric capacity C2 and transistor switch Q2 (it can be triode, field effect transistor or controllable silicon).And whether the charging voltage of C2 determines bidirectional triode thyristor T1 be triggered.Whether the conducting of transistor switch Q2 is determined by the voltage (depending on whether mechanical switch 2 is switched on) being applied to its voltage (being roughly the voltage on electric capacity C1) controlling pole (grid as when the base stage when triode and scene effect pipe) and main terminal (as the drain electrode when collector and emitter when triode and scene effect pipe and source electrode) place.In addition, whether the conducting of transistor switch Q2 determines the size of the charging voltage on C2.Under the prerequisite of resistance value appropriately setting current-limiting resistance, when Q2 not conducting, C2 can not be charged to the voltage that can trigger controllable silicon T1; And when Q2 conducting, C2 can be charged to the voltage place that can trigger controllable silicon T1.
Difference of injection time control circuit 3 be configured in response to mechanically controlled switch 2 first connect and the rear power supply of power supply is discharged to the first electric capacity C1 and rear connection in response to first power supply and the mechanically controlled switch 2 of power supply is not discharged to the first electric capacity C1.According to preferred embodiment (as shown in Figure 2), difference of injection time control circuit 3 comprises transistor switch Q1 (it can be triode, field effect transistor or controllable silicon), resistance R2 and R3.Mechanically controlled switch 2 is coupled to via resistor and the second electric capacity C2 in the control pole of Q1.Wherein the voltage (i.e. the first connection of mechanically controlled switch 1) whether extremely gone up by the control being applied to Q1 of the conducting of Q1 and be applied to Q1 main terminal (as the drain electrode when collector and emitter when triode and scene effect pipe and source electrode) on voltage (namely the rear power supply of power supply decides.And whether whether the conducting of transistor Q1 also determines transistor Q2 be indirectly switched on.
Controllable silicon and circuits for triggering 5 thereof comprise bidirectional triode thyristor T1 and bidirectional trigger diode D3.Wherein bidirectional trigger diode D3 is connected to the control pole G of bidirectional triode thyristor T1, and two of bidirectional triode thyristor T1 main terminals are connected on the loop of electrical load.Whether the charging voltage size on C2 determines bidirectional triode thyristor T1 and is switched on.Whether the work of electrical load is by mechanically controlled switch 2 and bidirectional triode thyristor T1 co-controlling.In other words, when the energising of L and N end, whether by the connection of mechanically controlled switch 2, whether whether two conditions decide with the conducting of bidirectional triode thyristor T1 for the work of electrical load.
False action-proof circuit 6 is optional circuit parts, and it comprises diode D2 and resistance R5 (as shown in Figure 3).Diode D2 plays the effect of being raised by the pilot angle current potential of transistor Q2, and the grid of Q2 is received N end by resistance R5, ensures that transistor Q2 pin is dragged down.D2 and R5 improves the antijamming capability of power-off protection apparatus of the present invention thus, and prevent in the presence of noise Q2 by false triggering.
Hereafter for Fig. 3 and 4, two further preferred embodiments of the present invention are shown.
Fig. 3 shows the detailed circuit diagram of power-off protection apparatus according to a first advantageous embodiment of the invention.L and N is wherein respectively input live wire and the zero line in two-phase alternating current source.L end is connected to N end via two main terminals of mechanically controlled switch 2, electrical load and bidirectional triode thyristor T1.It should be noted that this order of connection is not certain, the order of connection between above-mentioned parts can be adjusted as required.
The series circuit that first capacitor C1 and the first resistor R1 is formed is connected to the two ends of described power input.Preferably, the first capacitor C1 being parallel with a resistor R6, for when not powering, repid discharge being carried out to C1, to improve this device antijamming capability.
The first end of the second capacitor C2 is coupled to the control end (having two-way admittance diode D3 between the two) of described bidirectional triode thyristor T1, and the second end is connected to the main terminal away from mechanically controlled switch 2 in controllable silicon via two main terminals of transistor seconds switch.Preferably, away from being connected by a resistor R7 between the main terminal of mechanically controlled switch 2 and the first end of C2 in controllable silicon, to improve this device antijamming capability.
The first transistor switch is NPN type triode Q1 in this embodiment, and is connected in parallel on the first capacitor two ends (namely its collector electrode is connected between C1 and R1, and emitter is connected to N end).Its control end is connected to second end of capacitor C2 via the second resistor R2, and is connected to the main terminal away from described mechanically controlled switch in bidirectional triode thyristor via the 3rd resistor R3.
Transistor seconds switch is NPN type field effect transistor Q2 in this embodiment, its grid is connected to the contact between the first capacitor and the first resistor via diode D2, and the source electrode of the emitter of triode Q1 and field effect transistor Q2 is all connected to the main terminal away from described mechanically controlled switch in bidirectional triode thyristor.The wherein pilot angle current potential acting as raising Q2 of diode D2.Preferably, grid is connected to the main terminal away from described mechanically controlled switch in bidirectional triode thyristor via resistor R5, to be dragged down by grid.
Be coupled to the control end of described bidirectional triode thyristor via the 4th resistor R4 near the main terminal of described mechanically controlled switch in described bidirectional triode thyristor.Embodiment in Fig. 3 can realize triggering controllable silicon under the positive half wave of AC power, and when negative half-wave, due to the buffering effect of electric capacity C2, controllable silicon will keep conducting.
Fig. 4 shows the detailed circuit diagram of power-off protection apparatus according to a second, preferred embodiment of the present invention.Which use PNP triode and PNP field effect transistor and substitute NPN transistor above, and correspondingly have modified the conducting direction of diode.Those skilled in the art can find out, similar in the course of work of the circuit of Fig. 4 and Fig. 3, difference is that the negative half-wave realized under this embodiment by AC power triggers controllable silicon, and due to the buffering effect of electric capacity C2 under positive half wave, controllable silicon will keep conducting equally.
Although shown in above figure for triode and field effect transistor (it can be enhancement mode or depletion type) describe of the present invention may embodiment, but those skilled in the art it is easily understood that, when not deviating from the spirit and scope of the present invention, Q1 and Q2 that can implement above with the transistor switch of any band control end, such as triode, field effect transistor or controllable silicon.
The operation principle of unexpected startup when specific explanations power-off protection apparatus according to the present invention prevents electrical load from sending a telegram here suddenly after a loss of power is hereafter carried out for the circuit diagram shown in Fig. 3.
When switch 2 is in closure state and power input L and N place do not power, the electric charge on C1 and C2 is all discharged via the resistance (as R2, R3, R6 or R7) on circuit.And now when power supply is powered suddenly, the base stage of triode Q1 is by the voltage obtained from L end at once and enter pre-conducting state prior to Q2, then along with its collector electrode is powered, triode Q1 takes the lead in conducting, thus electric capacity C1 cannot fill height.And now field effect transistor Q2 will not be switched on owing to not having the very first time to obtain trigger voltage at grid place, electric capacity C2 cannot be charged to the voltage being enough to trigger controllable silicon T1 thus.Therefore, electrical load will not work, namely can not accidental activation.
If user's cut-off switch 2 this moment, cannot enter pre-conducting state because Q1 now lacks the trigger voltage at base stage place, so electric capacity C1 will be charged.Therefore field effect transistor Q2 will be in pre-conducting state, and namely its grid place has enough trigger voltages.Then, after user recloses switch 2, field effect transistor Q2 will take the lead in being switched on, thus make Q1 cannot conducting, and electric capacity C2 is further charged and is enough to trigger silicon controlled voltage (that is, make D3 conducting and trigger T1 thus).Thus electrical load will be started working.
And when power supply is first powered and connected after switch 2 the normal Booting sequence of user (i.e. under), electric capacity C2 also prior to triode Q1 conducting, will can be charged to and be enough to triggering silicon controlled voltage by field effect transistor Q2 thus.
Although illustrate especially with reference to the drawings and specific embodiments and describe the present invention, but should be understood that those skilled in the art are after having read the application, various changes in form and details can be made when not deviating from spirit and scope of the present disclosure as defined by the accompanying claims.The present invention is intended to above-mentioned various change to comprise within the scope of the invention.Protection scope of the present invention is only limited by claim.