CN101677238B - Low power solenoid driver circuit - Google Patents

Abstract

Present invention provide for controlling solenoidal system and method, its accurate timing guaranteed between drive circuit enables and solenoid triggers, provide dual energy grade to drive design, to reduce power consumption simultaneously.The present invention uses single enabling signal and supply two different energy grades, higher " setting " grade and relatively low " holding " grade to solenoid.The two grade produces based on enabling signal, and ensures to exist higher " setting " grade when triggering solenoid, so that undesirable timing instability minimizes.Specifically, it is provided that one drives solenoidal system in response to input signal, including: power switch, there is the first contact and the second contact；And circuit, for selecting to be applied to the voltage of described first contact.

Description

Low power solenoid driver circuit

The application is Application No. 200510066785.3, filing date April 30 in 2005 Day, the divisional application of the Chinese patent application of entitled " low power solenoid driver circuit ".

Background technology

Solenoid is widely used for converting electrical energy into mechanical movement, and, due to its effectiveness, It is used for being widely applied, is locked into simple door from the power of the high valve of time requirement to automobile Bell.

Briefly, solenoid includes electric wire, is generally cyclically wound coil.In coil Place the bar of magnetic conduction.When electric current is by coil, forming magnetic field, it causes bar relative to line Circle motion.In many examples, use bias component, such as spring, to stop at electric current When flowing is by coil, this bar is made to return to its inactive state.

A solenoidal simply example is traditional doorbell.When user drives doorbell, Coiled line is connected to power supply by this action, thus forms magnetic in coiled line ?.This causes piston movement that magnetic conducts and generally hits metal tone tuning plate, and it is formed logical The first sound often heard " stings " sound.After doorbell has been released, the offset part of such as spring Part makes piston return to its inertia position.In some doorbells, piston hits the second metal and adjusts Soundboard, the formation rising tone " rub-a-dub " sound.These identical principles are applicable to more complicated application, Such as valve.In this embodiment, the motion of piston generally makes to be hindered by piston in the normal state The opening of plug exposes, thus opens valve.

Due to the multiformity of application, these solenoids are driven to have multiple different method.At some In situation, cost is most important factor, and in other, power consumption or speed are permissible It it is most important factor.

The embodiment that the many of solenoid drive circuit is different can have been bought on market.It is true that Some manufacturers manufacture integrated circuit, and it can perform this function with single chip.In order to save Power, the regulation of some embodiments is driven through the amount of the electric current of coiled line.For doing this An individual common technology is, uses the technology being referred to as " copped wave " to change and is supplied to spiral shell The voltage of spool, to guarantee constant current hold.Voltage generally changes with jagged pattern, To limit the current to predetermined value.

In other embodiments, dual energy grade drive system is used.Solenoidal well-known Characteristic be, trigger solenoid and cause bar motion required for energy keep more than by bar At the energy required for this active state.Therefore, some circuit use two different grades of electricity Stream or voltage drive solenoid；Need first, or higher grade carrys out " setting " solenoid With needs second, or relatively low grade carrys out " holding " solenoid.

But, in the ongoing illustrated embodiment, these power save mechanism cause solenoidal timing Uncertain or unstable.Such as, some application require at the time that solenoid is triggered and energy Relation between the time being supplied to coil is accurate.Effective by using at specific enable signal Time service voltage simple circuit, it is possible to obtain this predictability, but this method power Inefficient.

The circuit being controlled electric current by " copped wave " voltage reduces total power consumption, but, Owing to being supplied to the change of the voltage of solenoidal copped wave, for solenoidal power enable and Time between this solenoid triggers is unpredictable.

Similarly, it is achieved the circuit of two different voltages or current class is likewise subjected to timing and becomes Change.Generally, these circuit use enable signal to indicate and supply " setting " voltage.Make By traditional constant time lag mechanism, grade then converts to relatively low " holding " voltage.But, Because the grade higher when circuit enables supplies, it may occur however that race conditio, its In, the order of the application of circuit enable and higher voltage is uncertain.In some cases, Higher voltage will exist when circuit enables, and cause the fast opening time.In other situations In, higher voltage will not be in existing when circuit enables, but will be when since then one section Exist after between, cause the slower opening time.

In some applications, when solenoid is in off position, capacitor charges.When needs touch When sending out solenoid, the electric charge of capacitor increases to available source voltage, by forming peak value Electric current, to guarantee that solenoid is switched fast.For the method, the only interval between triggering Time longer relative to capacitor charge rate, solenoidal timing just anticipated that.

In numerous applications, these power save mechanism the fine difference of the timing caused will not Impact uses the operating of solenoidal system.But, there is application, such as raw at integrated circuit Controlling the valve high to time requirement in product, wherein having between circuit enables and solenoid triggers can It is necessary with the time interval of precognition.In such applications, owing to power save can not be accepted The timing that technology causes is unstable, and circuit is often used without any power conservation techniques.

Therefore, one object of the present invention is used for controlling solenoidal system and method for providing, Instability between it makes circuit enable and solenoid trigger is minimum, realizes dual energy etc. simultaneously Level drives design, to reduce power consumption.

Summary of the invention

By the present invention, overcome problem of the prior art, it is provided that be used for controlling solenoidal System and method, it guarantees accurate timing, provides dual energy grade to drive design simultaneously, with Reduce power consumption.The present invention uses single enable signal and supplies two not to solenoid Same energy grade, higher " setting " grade and relatively low " holding " grade.The two Grade produces based on enabling signal, and ensures to exist higher " setting " when triggering solenoid Grade, so that timing instability minimizes.

According to an aspect, it is provided that a kind of in response to the input signal solenoidal system of driving, bag Include:

Power switch, has input and output so that the electric current between described input and output passes Pass effectively allowing and not allowed by the invalid of input signal by described input signal, described defeated Go out and be connected with described solenoid so that the electric current that effectively allows of described input signal flows through described spiral shell Spool；With

Circuit, for selecting to be applied to the voltage of described input, described circuit allows described defeated Enter signal described effectively before select the first voltage, and described effectively after a delay Afterwards, it is allowed to select second voltage lower than described first voltage, the voltage of wherein said selection It is connected with described input.

According to another aspect, it is provided that a kind of in response to the input signal solenoidal system of driving, Including:

Power switch, has input and output so that the electric current between described input and output passes Pass effectively allowing and not allowed by the invalid of input signal by described input signal, described defeated Go out and be connected with described solenoid so that the electric current that effectively allows of described input signal flows through described spiral shell Spool；With

Circuit, for selecting to be applied to the electric current of described input, described circuit allows described defeated Enter signal described effectively before select the first electric current, and described effectively after a delay Afterwards, it is allowed to select second electric current lower than described first electric current, the electric current of wherein said selection Path is connected with described input.

Accompanying drawing explanation

Fig. 1 is the schematic diagram showing one embodiment of the present of invention；

Fig. 2 is the sequential chart of the electrically operating showing the present invention；And

Fig. 3 is the schematic diagram of the pharmacy fuid distribution system showing the present invention.

Detailed description of the invention

Fig. 1 is the schematic diagram of a preferred embodiment of the present invention.Can be without departing from the present invention's This circuit is changed in the case of spirit.The preferred embodiment of this circuit have power input 11, Signal input 12 and output signal 13.

Power inputs, and 11, for the several parts in circuit 10 and solenoid 20 service voltage. Any applicable power supply (not shown) can be used to carry out the power for circuit 10 supply needs Input.The amount of the voltage of supply is not be particularly limited to, and can include 24,12 and 5 volts, and preferably 12 volts.

This circuit has the single input signal 12 for enabling solenoid 20.Implement at this In example, circuit 10 makes, and when enabling signal 12 and being logic high, voltage can be by output Signal 13 is delivered to solenoid 20.Replace, it will be understood by those skilled in the art that This circuit can be designed so that solenoid 20 is driven when enabling signal 12 for logic low.

Circuit 10 has single output signal 13, and it is connected with solenoid 20.Defeated at this Go out signal 13 to there is voltage and allow solenoid 20 to close, and there is no voltage in output signal 13 Solenoid 20 is caused to be opened.

In this embodiment, power inputs 11 service voltages to voltage adjuster U1.This adjusts Device U1 produces the second relatively low voltage 101, and solenoid 20 uses this voltage to be maintained at closedown Position.Capacitor C1 is connected with the output of voltage adjuster, to help to improve output voltage Stability.Although preferably voltage adjuster U1 is 5V switch adjuster, it has high efficiency To minimize power loss and heating, other embodiments is also within the scope of the invention.Such as, Although heat generation may be much higher, the second relatively low voltage 101 can use linear regulator to produce Raw.Alternatively, circuit 10 can have the second power input formed the most elsewhere, The voltage that its supply is relatively low, it is not necessary to produce this voltage in this circuit.

Connect between the output and the input of power switch Q2 of voltage adjuster U1 diode D2, the anode of diode D2 is connected with voltage adjuster U1, the negative electrode of diode D2 and merit Rate switch Q2 is connected.The also output with power switch Q1 of the negative electrode of diode D2 is connected, mark It is shown as 104.Power switch Q1 and Q2 represents preferred embodiment, although other realization is also Possible.It is, for example possible to use discrete field-effect transistor and its relevant protection circuit are come Perform same function.In this embodiment, diode D2 is Schottky diode, with Littleization forward drop, but any diode can be used to realize this circuit.

Input voltage 11 also with the input of power switch Q1 and a lead-in wire phase of resistor R2 Even.The relative lead-in wire of resistor R2, is denoted as 102, with the lead-in wire of resistor R1, Capacitor C2 and preferably there is the input phase of phase inverter U2 of schmidt trigger type input Even.

The phase inverter with the input of schmidt trigger type is such a phase inverter, wherein, protects The card output switch input voltage when a direction can be measured than output switch at another Voltage during direction is high.In other words, the typical schmidt trigger type of 12V supply is used Phase inverter can cause, and when input is increased to more than about 7.0 volts, is outputted to low State.But, during until input falls to approximately less than 4.7 volts, output just can return to High state.Difference between these values ensures when input voltage is slowly increased or reduces, equipment Output will not vibrate.

Another lead-in wire of capacitor C2 is connected to ground.Another lead-in wire and two of resistor R1 The anode of pole pipe D1 is connected.

The output of phase inverter U2, is denoted as 103, is connected with a lead-in wire of resistor R3. The relative lead-in wire of resistor R3 inputs with the enable of power switch Q1 and is connected.

Finally, the negative electrode of diode D1 and input signal 12 and draw with one of resistor R4 Line is connected.Another lead-in wire of resistor R4 inputs with the enable of power switch Q2 and is connected.Merit The output of rate switch Q2 is connected with solenoid 20.

Layout described above will be described to the electric operating of this circuit now.

Assuming that signal input 12 is positioned at its low state, it is 0 volt at its voltage of this state or connects Nearly 0 volt.This low-voltage promotes power switch Q2 inertia, is effectively inputted from it Output disconnects.In the case, do not have voltage to pass through circuit 10 and be supplied to output signal 13, Output signal 13 inertia.It addition, the low state of input signal 12 causes electric current to flow through two poles Pipe D1 and resistor R1, thus exhaust the electric charge of sufficient power from capacitor C2.In steady statue, The voltage of the input of phase inverter U2 can be expressed as:

V=0.7V+ (12V-0.7V) * R1/ (R1+R2), wherein, 0.7V is by two poles The forward drop of pipe D1.

This voltage 102 in the input of phase inverter is substantially low, to ensure that phase inverter U2's is defeated Source is in high state, and it causes power switch Q1 to enable, thus by the voltage in its input, 12V, is delivered to its output.Owing to the output of this voltage ratio voltage adjuster U1 is much higher, two Pole pipe D2 non-conducting.Therefore, when off status, although power switch Q2 inertia, 12V It is supplied to its input.The voltage changed in the time 200 shows at this dot circuit in Fig. 2 State.

When input signal 12 is in time being switched to 12 volts for 0 volt, power switch Q2 enables, Thus the voltage in its input is delivered to its output.As previously described, power switch is worked as When first enabling, its input is 12 volts.This illustrates in the time 201 in fig. 2.

The high voltage of input signal 12 causes diode D1 to stop conduction electric current, thus cuts off electricity The discharge path of container C2.Owing to diode D1 no longer conducts, owing to capacitor C2 passes through Resistor R2 receives electric current from input voltage, and capacitor C2 starts to charge up.When capacitor charges Time, the voltage of the input of phase inverter U2 increases, the speed of the increase value by R2 and C2 Determine.Charge rate calculates the longest, during to guarantee that higher voltage is supplied to solenoidal Between long enough so that it is completely into " setting " position, including possible machinery bounce-back and its Its phenomenon.It is preferred equal to or more than the charge rate of this value.When voltage arrives the highest During grade, the output step-down of phase inverter U2, so that power switch Q1 inertia.Due to merit Rate switch Q1 inertia, 12 volt signal are no longer supplied to its output by it.Due to this voltage No longer existing, diode D2 conducts, it is allowed to the output of voltage adjuster U1 is placed on power and opens Close the input of Q2.Owing to power switch Q2 enables, this low-voltage flows directly to solenoid 20. This illustrates in the time 202 in fig. 2.

This circuit is maintained at this state until input signal 12 changes again.When input signal 12 When changing back to low state, power switch Q2 will cut off immediately because its inertia, as Shown in the time 203 in Fig. 2.Diode D1 will start to conduct electric current, thus the electricity that discharges Container C2.Discharge rate is determined by the value of R1 and C2, and will be ordinarily selected to allow Capacitor repid discharge, the maximum load current of the equipment of the input of observation driving simultaneously 11 is specified Value.When capacitor is substantially discharged, the input of phase inverter U2 is substantially low, to cause phase inverter The output of U2 is converted to its high state, thus enables power switch Q1.This makes input voltage 11 can be for delivery to the input of power switch Q2, and the transformation next time for input signal 12 is made Prepare.This illustrates in the time 204 in fig. 2.

Although this embodiment uses two different electric pressures to arrange and keep solenoid, this Invention is not limited to only this embodiment.Such as, two voltages are replaced with two different current sources Grade is within the skill of this technology, and can obtain same effect.

The present invention described here be used for pharmacy fuid distribution system, the most aseptic liquid with Pinpoint accuracy is measured and distribution.Figure 3 illustrates typical system.This system uses a pair The liquid volume in disposable parts measured by choke valve.These choke valves are driven by solenoid Dynamic.This application is high, because it determines liquid volume to the timing demands of choke valve.Even it is micro- Little fluctuation also is able to the volume of impact distribution.Because solenoid timing is quick to the voltage of supply Sense, it is necessary to supply constant nominal voltage to encourage this valve solenoid.But, due to temperature also Affect solenoid timing, it is necessary to minimize the self-heating of valve in active state.Therefore, twin voltage Operating becomes necessary.

The accuracy of the valve owing to being encouraged by solenoid is most important standard, when needed, It is necessary for supplying stable voltage.Can't stand inclined-plane rising delay.

In the actual realization of the present invention, it has proved that the heating of valve may remain in substantially low Grade, without producing any negative effect due to voltage conversion on valve timing.

With reference to Fig. 3, show common pharmacy fuid distribution system with 110.System 110 is wrapped Including fluid chamber 112, it is filled by feeding pipe 116 from fluid source 118.Level controls Device 122 monitors the level of the fluid in chamber 112, and, if this level is reduced to make a reservation for Threshold value below, controller (not shown) by drive supply solenoid 121 open confession To valve 120.

Chamber 112 includes exporting 124 and entrance 138.Controller (not shown) drives spiral shell Spool 131, it opens again Outlet solenoid 130.Discharge pipe 126 and ascending pipe 136 and row Go out valve 128 to connect.Ascending pipe 136 is shape between entrance 138, chamber 112 and outlet 124 Become closed loop, thus eliminate the needs ventilated.Dump valve 128 controls the accurate of pharmacy fluid Release, and control by discharging solenoid 129, it is driven by controller (not shown) Dynamic.The grade of the degree of accuracy owing to needing, discharges solenoid 129 and supply solenoid 131 leads to Cross the present invention to drive, as described with reference to fig. 1.In preferably realizing, supply valve 130 Formed with the solenoid 131 and 129 of each of which with the form of electric drive valve with dump valve 128 Overall.

In current realization, the present invention is for driving up to eight valves independently, it is only necessary to one Power supply and an adjustor.A feature of the present invention is, when operating more than one helical Guan Shi, the timing of voltage switching is unrelated with each circuit.By increasing corresponding circuit, permissible Drive any number of solenoid.

The relevant United States Patent (USP) that patent is Denis Keyes et al. 5680960 and 5480063, Describing volume fluid distributing equipment, its disclosure content is incorporated by reference herein addition.

Claims (1)

1. drive a solenoidal system in response to input signal, including:

Power switch, there is input and output, making the transmission of the electric current between described input and output effectively allowing and not allowed by the invalid of input signal by described input signal, described output is connected with described solenoid so that the electric current that effectively allows of described input signal flows through described solenoid；With

Circuit, for selecting to be applied to the voltage of described input, described circuit allow described input signal described effectively before select the first voltage, and described effectively after a delay after, allowing to select second voltage lower than described first voltage, the voltage that wherein said circuit selects is connected with described input.

2. drive a solenoidal system in response to input signal, including:

Power switch, there is input and output, making the transmission of the electric current between described input and output effectively allowing and not allowed by the invalid of input signal by described input signal, described output is connected with described solenoid so that the electric current that effectively allows of described input signal flows through described solenoid；With

Circuit, for selecting to be applied to the electric current of described input, described circuit allow described input signal described effectively before select the first electric current, and described effectively after a delay after, allowing to select second electric current lower than described first electric current, the path of the electric current that wherein said circuit selects is connected with described input.