Embodiment
For making the purpose, technical solutions and advantages of the present invention clearer, below in conjunction with embodiment and accompanying drawing, the present invention is described in more detail.
Referring to Fig. 1, be the structural representation of embodiment of the invention DC power supply switch, this DC power supply switch comprises electric voltage exception control module 110, time-delay and slope control module 120, hand control switch module 130 and power switch module 140.
Electric voltage exception control module 110, be used to detect the voltage of input dc power source switch for just often, transmit the signal of conducting power switch module and give time-delay and slope control module 120, when the voltage that detects the input dc power source switch is unusual, transmits the signal that disconnects the power switch module and give time-delay and slope control module 120.Electric voltage exception control module 110 comprises that overvoltage/undervoltage detection module 111 and electric voltage exception close output control module 112.
Overvoltage/undervoltage detection module 111, be used for the voltage of input dc power source switch is carried out the overvoltage/undervoltage detection, detect voltage and just often close output control module 112 and send the normal index signal of voltages, detect voltage and be overvoltage or close the index signal that output control module 112 sends electric voltage exceptions to electric voltage exception when under-voltage to electric voltage exception.
Electric voltage exception is closed output control module 112, is used for according to the normal index signal of voltage by 111 transmission of overvoltage/undervoltage detection module that receives, and transmits the signal of conducting power switch module and gives time-delay and slope control module 120; Index signal according to the electric voltage exception that is transmitted by overvoltage/undervoltage detection module 111 that receives transmits the signal that disconnects the power switch module and gives time-delay and slope control module 120.The DC power supply input of DC power supply switch can also be closed the input of output control module 112 as electric voltage exception, closes output control module 112 for electric voltage exception power supply is provided.
The voltage of 110 pairs of input dc power source switches of electric voltage exception control module carries out overvoltage/undervoltage and detects, avoided because of input voltage unusual (too high or too low), cause the electric power system abnormal work, even cause DC power supply switch or power supply unit to damage, occur security incident or hidden danger.
Time-delay and slope control module 120, place electric voltage exception to close between output control module 112 and the power switch module 140, be used for when receiving electric voltage exception and close the signal of the conducting power switch module that output control module 112 transmits, the conducting of time-delay power switch module 140 is controlled the voltage ramp rising of output DC source switches or is dropped to normal voltage by power switch module 140; When receiving electric voltage exception and close the signal of the disconnection power switch module that output control module 112 transmits, power controlling switch module 140 disconnects.The input of the DC power supply of DC power supply switch can also be as the input of time-delay and slope control module 120, for time-delay and slope control module 120 provide power supply.
Can the delay time conducting of power switch module 140 of time-delay and slope control module 120, and by the control to power switch module 140 makes the voltage ramp that offers power supply unit by power switch module 141 rise or descend.Offer the voltage ramp rising of power supply unit or the process that descends, just the process of power switch module 140 from the beginning conducting to complete conducting.Like this, realized the function of constant power supply output starting current or current-limited startup, avoided producing big surge starting current phenomenon under than the large capacitive load condition, can not produce arc phenomenon, thereby improve the life-span of switching device.
Hand control switch module 130, be connected with electric voltage exception control module 110, particularly, closing output control module 112 with electric voltage exception is connected, when the voltage that is used for detecting the input dc power source switch in electric voltage exception control module 110 is unusual, control electric voltage exception control module 110 is in self-locking state, make its output remain the signal that disconnects the power switch module, send power switch module 140 to by time-delay and slope control module 120, up to removing the self-locking state of electric voltage exception control module 112 by manually controlling hand control switch module 130.
Hand control switch module 130 is optional, and the physical circuit figure of its realization can be in conjunction with Fig. 4.Among Fig. 4, when the contact 2 and the contact 3 of hand control switch module 130 joins, if electric voltage exception control module 110 detects the voltage of input dc power source switch for unusual, then electric voltage exception control module 110 forms self-locking circuit with hand control switch module 130, make electric voltage exception control module 110 be in self-locking state, output disconnects the signal of power switch module.Afterwards, even electric voltage exception control module 110 detects the voltage of input dc power source switch for normal, the output of electric voltage exception control module 110 remains the signal that disconnects the power switch module, remove self-locking state, the hand control switch module 130 among Fig. 43 is switched to contact 1 and gets final product from the contact.After treating that the voltage of input dc power source switch is normal, can be again hand control switch module 130 1 be switched to contact 3 from the contact.As seen, the voltage that hand control switch module 130 can prevent the input dc power source switch is at under-voltage point or cross the pressure point continuous wave and make the conducting repeatedly of power switch module, disconnection when moving, and causes the damage to DC power supply switch or power supply unit.
Power switch module 140 is used under the control of time-delay and slope control module 120, and the voltage that the input dc power source switch is provided perhaps, disconnects the voltage of the input dc power source switch that offers power supply unit to power supply unit.Power switch module 140 can adopt realizations such as MOS switch or triode.
The normal display module 150 of output voltage links to each other with power switch module 140, and the state when being used to realize DC power supply switch to the power supply unit normal power supply shows.The normal display module of output voltage 150 is optional.
According to the actual design situation, the implementation of embodiment of the invention DC power supply switch structure is varied, here, is that example is specifically described structure shown in Figure 1 with circuit shown in Figure 2.Wherein power switch module 140 adopts the MOS switch to realize.
Referring to Fig. 2, be the circuit diagram one of embodiment of the invention DC power supply switch.Fig. 2 is a specific implementation circuit of corresponding diagram 1, and wherein each partial circuit is specifically referring to Fig. 3 to Fig. 6.
Referring to Fig. 3, be the circuit diagram of overvoltage/undervoltage detection module 111 among Fig. 2, among Fig. 3, the circuit of overvoltage/undervoltage detection module adopts 2 TL431 (U1, U2) and peripheral resistance to realize that described peripheral resistance comprises R1, R2, R3, R4 and R5.TL431 is the voltage comparator with reference voltage, and its reference voltage V ref is 2.5V or 1.25V.Realize that by R1, R2 and U1 overvoltage detects, and realizes under-voltage detection by R3, R4 and U2.The overvoltage test point of input overvoltage/undervoltage detection module circuit is: (1+R1/R2) * and Vref; The under-voltage test point of input overvoltage/undervoltage detection module circuit is: (1+R3/R4) * and Vref.When the voltage of importing under-voltage detection module circuit was between under-voltage test point and overvoltage/undervoltage test point, under-voltage detection module circuit was output as low level voltage, otherwise, be output as high level voltage.
Referring to Fig. 4, close the circuit diagram of output control module 112 and hand control switch module 130 for electric voltage exception among Fig. 2, this circuit is input as the output of the circuit of overvoltage/undervoltage detection module 111.The high level voltage that is input as when electric voltage exception closing control module 112, just the supply voltage of input dc power source switch is unusual, when promptly being lower than under-voltage test point or being higher than the overvoltage test point, NMOS pipe Q1 conducting, NPN triode Q2 by, NPN triode Q3 conducting, electric voltage exception is closed output control module 112 and is output as low level voltage; Close the low level voltage that is input as of output control module 112 when electric voltage exception, just the supply voltage of input dc power source switch is a normal value, the supply voltage that is the input dc power source switch is between under-voltage test point and overvoltage test point, and electric voltage exception is closed output control module 112 and is output as high level voltage.
If will 2 be connected to contact 3 among the hand control switch module SW, if this moment DC power supply switch be input as abnormal voltage, then electric voltage exception is closed output control module 112 and is in self-locking state, and electric voltage exception is closed output control module 112 and is output as low level voltage.If the input of DC power supply switch becomes normal voltage afterwards, then electric voltage exception is closed output control module 112 and still is in self-locking state, and electric voltage exception is closed output control module 112 outputs and kept low levels.In this case, hand control switch module SW 3 is switched to contact 1 from the contact, be transformed into contact 2 again, just can remove self-locking.
Among Fig. 4, input signal and output signal that electric voltage exception is closed output control module 112 realize and logical relation by diode D1, D2, capacitor C 1 is anti-shake electric capacity, and it is constant that electric voltage exception is closed the output of output control module 112 when being used to guarantee the supply voltage transient change of input dc power source switch.
Referring to Fig. 5, be the circuit diagram of time-delay and slope control module 120 and MOS switch among Fig. 2.Below MOS switch shutoff working condition and closed working condition are described respectively.
1) the MOS switch turn-offs working condition.Time-delay and slope control module 120 be input as the output that electric voltage exception is closed output control module 112, the low level that is input as when time-delay and slope control module 120, be that the input voltage of DC power supply switch is when unusual, PNP triode Q4 conducting among Fig. 5, the voltage of capacitor C 2 is released by Q4 and R14, the grid of MOS switch-source voltage VGS is lower than threshold voltage, the MOS switch by, the output voltage of DC power supply switch is 0.
2) MOS switch closure working condition.The high level that is input as when time-delay and slope control module 120, be DC power supply switch input voltage just often, among this Fig. 5 PNP triode Q4 by, the input voltage of DC power supply constitutes the transient current path by C2, D3, C3, R19 and output load capacitance, R19 is a current-limiting resistance, usually feedback capacity C3 is much smaller than other electric capacity, and its both end voltage reaches the input voltage of DC power supply switch rapidly.
Then, R15, R16 charge to capacitor C 2, and when the charging of C2 both end voltage reached a certain definite magnitude of voltage [Vgh (th)+Vd], the MOS switch gate reached on state threshold voltage Vgh (th), the MOS switch begins conducting, and the length of ON time is determined jointly by resistance R 15, R16 and capacitor C 2.From R15, R16 capacitor C 2 is charged, charging to the C2 both end voltage reaches the process of a certain definite magnitude of voltage [Vgh (th)+Vd], the process of the metal-oxide-semiconductor conducting of just delaying time.
After the MOS switch begins conducting, C2 is continued charging make MOS switch gate source reach platform voltage (Vplt), at this moment feedback capacity C3, the source/drain electrode of MOS switch, time-delay and slope control module 120 output voltages change with identical voltage change ratio; The output voltage of time-delay and slope control module 120 is with the input voltage value of constant voltage rate of change from 0V to the DC power supply switch; After the output voltage of time-delay and slope control module 120 reaches the input voltage value of DC power supply switch, R15, R16 continue the input voltage value that charging reaches DC power supply switch to capacitor C 2, the conducting resistance RDS minimum of MOS switch, conducting voltage VDS also reaches minimum, DC power supply switch output normal voltage.Begin the process of conducting from the MOS switch, for rising on the MOS switch control output voltage slope, until the process of MOS switch output normal voltage to DC power supply switch output normal voltage.
Feedback capacity C3 size is determined by surge current and output load capacitance that the electric current that flows through feedback capacity C3, the power supply output of time-delay slope control module 120 allow.The ratio of the surge current that the time-delay and the electric power output voltage rate of change of slope control module 120 allow for the power supply output of time-delay and slope control module 120 and the output load capacitance of time-delay and slope control module 120.
Referring to Fig. 6, be the circuit diagram of the normal display module 150 of output voltage among Fig. 2, the normal display circuit of electric power output voltage adopts LED serial connection current-limiting resistance R20 to realize.When the input voltage of DC power supply switch was between under-voltage test point and overvoltage test point, electric power output voltage was normal, and LED is lighted.Under the different electrical power voltage input condition of DC power supply switch, by selecting serial connection current-limiting resistance R20, the operating current that makes LED is in 5~10mA scope.
To be example with dc positive power input dc power source switch be illustrated the DC power supply switch of Fig. 1 Fig. 2, and the circuit with Fig. 7 carries out concrete illustrating to the situation of dc negative supply input dc power source switch below.Referring to Fig. 7, be the circuit diagram example two of embodiment of the invention DC power supply switch, to compare with the circuit of Fig. 2, it is similar respectively that overvoltage/undervoltage detection module, electric voltage exception are closed the normal display module of output control module, hand control switch module and output voltage.Because this moment DC power supply switch be input as negative supply, so some difference of specific implementation circuit of time-delay and slope control module and MOS switch, the MOS switch is a P type MOS switch among Fig. 2, the MOS switch is a N type MOS switch among Fig. 7.When described time-delay and slope control module receive electric voltage exception and close the signal of the conducting power switch module that output control module transmits, the conducting of time-delay power switch module, the voltage ramp by power switch module controls output DC source switch drops to normal voltage; When receiving electric voltage exception and close the signal of the disconnection power switch module that output control module transmits, the power controlling switch module disconnects.
Certainly, the DC power supply switch that the thinking of the employing embodiment of the invention can realize is not enumerated here one by one not only for the above-mentioned circuit.
The embodiment of the invention also provides a kind of implementation method of DC power supply switch, and this method comprises:
The voltage that detects the input dc power source switch is for just often, will offer the voltage time-delay of the input dc power source switch of power supply unit, and rises on the slope or drop to normal voltage; When detecting the electric voltage exception of input dc power source switch, disconnect the voltage of the input dc power source switch that offers power supply unit.
Alternatively, in the time-delay of the voltage of the input dc power source switch that offers power supply unit, and rise on the slope or drop to after the normal voltage, this method comprises: show the state when DC power supply switch is given the power supply unit normal power supply.
The DC power supply switch of the embodiment of the invention has realized the voltage of input dc power source switch is detected and controls, voltage at the input dc power source switch is just often just powered to power supply unit, and the voltage of exporting to power supply unit from DC power supply switch is delayed time and the slope processing, realize that constant current and slope output voltage are to power supply unit, like this, can as prior art, not produce arc phenomenon.Thereby the DC power supply switch of the embodiment of the invention has improved the performance of electronic switch.
And embodiment of the invention scheme can adopt routine, general-purpose device design, and its realization is easy.
Need to prove that the form that embodiment of the invention DC power supply switch can modular circuit appears in the circuit design of correlation function demand, merges use with relevant device; Also can the little module parts appear in the equipment of related needs with form independently.
Moreover, when the power switch module of DC power supply switch adopted the MOS switch, the DC power supply switch of the embodiment of the invention also comprised following effect:
1) the DC power supply switch cost mainly is presented as the cost of 2 general-purpose device TL431 and power MOS pipe, and the cost of 2 general-purpose device TL431 and power MOS pipe is low, like this, has reduced cost.
2) DC power supply switch is easy to adjust, at different capacity, voltage requirements, only needs to select the MOS switch of different size, can meet design requirement.
When 3) the power switch module of DC power supply switch is the MOS switch, only be connected in series the MOS switch in the major loop of embodiment of the invention DC power supply switch, it is unique dissipative cell in the DC power supply switch, thereby the volume of embodiment of the invention DC power supply switch is mainly reflected on the MOS switch, and the internal resistance of power MOS switch tube is very little during switch closure, thereby the volume of DC power supply switch is less.Like this, reduce the volume of DC power supply switch, also be convenient to install, can be made into powerful mains switch.
Above-described specific embodiment; purpose of the present invention, technical scheme and beneficial effect are further described; institute is understood that; the above only is specific embodiments of the invention; and be not intended to limit the scope of the invention; within the spirit and principles in the present invention all, any modification of being made, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.