CN1120798A - Automatic illumination intensity control apparatus for a discharge lamp - Google Patents
Automatic illumination intensity control apparatus for a discharge lamp Download PDFInfo
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- CN1120798A CN1120798A CN 94116324 CN94116324A CN1120798A CN 1120798 A CN1120798 A CN 1120798A CN 94116324 CN94116324 CN 94116324 CN 94116324 A CN94116324 A CN 94116324A CN 1120798 A CN1120798 A CN 1120798A
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- discharge lamp
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Abstract
The automatic brightness controller for discharge lamp is composed of chopper for raising rectified voltage, inverse transformer for converting Dc voltage from chopper into AC one with higher frequency for driving discharge lamp, brightness test unit, brightness setting unit, the unit for regulating or cutting-off output voltage from inverse transformer according to difference between tested and set brightnesses, and overcurrent protector.
Description
The present invention relates to be used for for example automatic illumination intensity control apparatus of fluorescent lamp of discharge lamp, it automatically makes the brightness of irradiation area maintain on the intensity of user's setting, and can avoid overcurrent to flow through discharge lamp.
Recently, the illumination control technology has been carried out multiple improvement, they can use the inverse type drive circuit to change the illumination of discharge lamp.
Fig. 1 is a block diagram, and it shows the ballast for discharge lamp of the prior art that has illumination control briefly.
Referring to Fig. 1, ballast for discharge lamp comprises discharge lamp 22 (for example fluorescent lamp); The control button 10 of duty ratio is set, and it has realized the illumination control of discharge lamp 22; Generation has the oscillator 12 of the oscillator signal of preset frequency; Oscillator signal is transformed to the frequency changer 14 of difference frequency signal; Variable pulse width modulator 16, its recently changes duty ratio by 14 output signals of frequency changer according to the duty of opening-close that is provided with by control button 10; Switch element 18, it is controlled it by the modulation signal of variable pulse width modulator 16 outputs and opens or closes; And first and second transformers 20, it obtains induced voltage according to opening-closing of switch element 18 checkers.
In above-mentioned ballast for discharge lamp, control illumination by the electrical power that change is delivered to discharge lamp 22 according to the duty ratio of opening-close that is provided with by control button 10.About the situation of prior art,, will omit in this specification it will be described further because its detailed content done announcement in United States Patent (USP) the 4998046th.
Yet prior art problems is: in the circuit transmission undesirable additional circuit element need be set, adopting wireless transmission is remote control manufacturing cost costliness.
And regardless of the natural brightness in zone to be illuminated, the output of discharge lamp all is fixed on the set level of user.
And, the frequency band overlaid of employed frequency band and remote control commonly used, thus the work of other electric equipments influenced.
An object of the present invention is to provide a kind of automatic illumination intensity control apparatus that is used for discharge lamp; it can change the illumination of lamp; make the brightness of irradiation area maintain continuously on the set level of user, thus protection user's eyesight, and reduce the electrical power that discharge lamp consumes.
Another object of the present invention is to provide a kind of automatic illumination intensity control apparatus that is used for discharge lamp, and it can prevent that overcurrent from flowing through discharge lamp, thereby has protected this device.
When being to provide a kind of automatic illuminance that is used for discharge lamp to control, another purpose of the present invention puts, it can prolong the life-span expectation value of discharge lamp, and it can suppress to influence the generation of the noise signal of other electric equipment work by the power factor that correction is added in the AC power on the discharge lamp.
In order to achieve the above object, the automatic illumination intensity control apparatus of discharge lamp generally includes the AC chopper circuit, the direct voltage that raises and can obtain by AC mains is compressed into capable rectification with it; Inverter circuit because of it will be the alternating voltage with preset frequency by the dc voltage conversion of AC transform circuit output, thereby drives discharge lamp; The device of the brightness in zone to be illuminated is set; Detect the device of the brightness in zone to be illuminated; And make the out-of-work device of inverter circuit during greater than set brightness when the brightness that detects.
Therefore, when the natural brightness in zone to be illuminated during greater than the set brightness of user, discharge lamp is consumption of electric power not.
Described control device also can comprise such device, when the brightness that detects during less than set brightness, described device is proportional to the difference that brightness and sensed luminance are set and changes voltage by AC transform circuit output, thus the electrical power of controlling in the discharge lamp automatically to be consumed according to natural brightness.
According to further describing that the present invention did, this control device also can comprise the device that is used for detecting the current value that flows through discharge lamp, and when detecting current value, can make the out-of-work device of inverter circuit automatically, thereby avoid discharge lamp to suffer any destruction greater than reference current value.
By below in conjunction with the description that accompanying drawing carried out, will make the present invention will be easier to understand, wherein:
Fig. 1 is the block diagram that shows the ballast for discharge lamp of the prior art that has illumination control briefly;
Fig. 2 is according to a kind of sketch that is used for the automatic illumination intensity control apparatus of discharge lamp of the present invention;
Fig. 3 is the physical circuit figure of control device shown in Figure 2; And,
Fig. 4 is the flow chart that is used for illustrating the work of the control device according to the present invention.
In order to understand the present invention better and to understand other further purposes simultaneously, advantage and function are now set forth following disclosure and appended claim in conjunction with above-mentioned accompanying drawing.
Referring to Fig. 2, illuminance control device comprises a discharge lamp drive part 140, and it lights discharge lamp after the AC mains pressure is transformed to another alternating voltage with higher frequency; Brightness test section 110 and dump part 120, they are used for detecting the brightness in zone to be illuminated, and cut off the power supply that is added on the lamp during greater than the set brightness of user in sensed luminance; Power factor correction and illumination are regulated part 130, and it makes the voltage and current homophase that adds to discharge lamp, and change the power that adds to discharge lamp with sensed luminance and difference that brightness is set during less than the set brightness of user when the brightness that detects with being directly proportional; Prevent part 150 with overcurrent, its detects the current value flow through discharge lamp, and when the current value that detects during greater than reference current value its cut-out add to the power supply of discharge lamp.
Referring to Fig. 3, discharge lamp drive part 140 can generally be divided into two sections: first chopper circuit 140A, the direct voltage that raises and obtain by AC mains is compressed into capable rectification with it; Another is inverter circuit 140B, is to have for example alternating voltage of about 30KHz of higher frequency with it with dc voltage conversion, and lights discharge lamp LAMP with it.
Power factor correction and illumination are regulated part 130 and are comprised an operational amplifier OP2, and its amplifies and poor between the voltage Vsen of brightness in zone to be illuminated and the preset reference voltage E1 represented in output; Operational amplifier OP3, its output voltage E4 after to the process dividing potential drop of output voltage E3 and chopper circuit 140A compares; Multiplier MT, it multiply by by the voltage to carrying out through the input voltage Vi after the full-wave rectification obtaining after the dividing potential drop suitably with the output voltage of operational amplifier OP3; Resistor R 7, the current transformation that it will flow through field-effect transistor Q2 is a correspondent voltage; Operational amplifier OP5, it compares the output voltage of multiplier MT and the voltage at resistor R 7 two ends; Operational amplifier OP4, it is to adding pulse signal and preset reference voltage E2 compares; Locking circuit G1 to G4 is used for temporarily storing the output state of operational amplifier OP5, and open then or close transistor Q3, and resistor R 5, it has limited the electric current on the grid that flows through field-effect transistor Q2.The reference character R6 and the C4 that do not do hereinbefore to describe represent a resistor and capacitor respectively, eliminate the rising edge of current spike with them; Reference character C2 represents a capacitor, in order to contained pulsation part among the output voltage E4 after the elimination dividing potential drop.
Power factor correction and illumination are regulated part 130 and should be realized by an integrated circuit, for example, can use the label made by Korea S Samsung Co., Ltd to become circuit to realize as the current collection of KA7514.
Overcurrent prevents that part 150 from comprising the coil T2 that carries out current detecting; Resistor R 12, it is a voltage with the current transformation that detects; Circuit, it comprises diode, resistor and capacitor D4, R13 and C8, it carries out rectification by the voltage to resistor R 12 two ends and smothing filtering produces direct voltage E5; And operational amplifier OP6, when direct voltage E5 was higher than reference voltage Vref 2, it quit work inverter circuit 140B.
To describe the working condition that is used for the illuminance control device of discharge lamp according to the present invention in detail below.
Referring to Fig. 4,, the user carry AC mains, voltage Vi by the rectification of diode-bridge circuit (not shown) to be transported to chopper circuit 140A to device if connecting the switch (not shown).Subsequently, described chopper circuit 140A produces voltage (Vdd) according to conducting and cycle deadline of transistor Q2, and it is determined by following formula:
Vdd＝Vi(Ton+Toff)/Toff
That is, coil L1 storage power when transistor Q2 is in conducting state, and when transistor Q2 was in cut-off state, electric current flow through inverter circuit 140B, thus changed the average power that adds to discharge lamp LAMP.
On the other hand, the user can accurately be provided with a required illumination by regulating variable resistance VR.
Available cadmium element constitutes brightness detector S1, and its resistance diminishes when brightness becomes big.Therefore, the voltage Vsen at the big more then variable resistance of brightness VR two ends is just high more.
When voltage Vsen is higher than reference voltage Vref 1, that is, when the result of determination of step S100 was " YES ", operational amplifier OP1 exported high level signal, thereby caused on the A point potential drop low.Therefore, transistor Q4 is cut off, thereby extinguishes discharge lamp LAMP.
As mentioned above, in the time only just satisfying set brightness by natural daylight, discharge lamp is extinguished, thereby has reduced power loss.
When voltage Vsen is lower than reference voltage Vref 1, that is, when the judged result of step 8100 is " NO ", operational amplifier OP1 output low level signal, thus allow transistor Q3 and Q4 alternation.
On the other hand, suitable coefficient among the operational amplifier OP2 use step S110 amplifies the difference between reference voltage E1 and voltage Vsen, with changing the voltage Vdd that adds to inverter circuit 140B through the difference voltage E3 that amplifies, wherein difference voltage E3 is decided by following formula subsequently:
E3＝E1((R2+R3)/R2)-Vsen(R3/R2)
In step S120, operational amplifier OP3 is to difference voltage E3 and undertaken suitably by the output voltage V dd to chopper circuit 140B that the resulting voltage E4 of dividing potential drop compares.When difference voltage E3 is higher than the output voltage E4 of dividing potential drop gained, that is, when the judged result of step S120 was " NO ", operational amplifier OP3 exported a high level signal subsequently, and thereby made transistor Q2 conducting.Therefore, brightness is big more, and then difference voltage E3 is more little.Correspondingly, voltage Vdd reduces, thereby has reduced to add to the power of discharge lamp LAMP.
Below detailed description is used for proofreading and correct the working condition of apparatus structure of the power factor of the electrical power of transporting to inverter circuit 140B.
Multiplier MT uses by suitably input voltage Vi being carried out voltage that dividing potential drop obtains and multiply by voltage by operational amplifier OP3 output, and subsequently it is transported to noninverting (+) input of operational amplifier OP5.Output with multiplier MT limits the electric current that flows through coil L1.Corresponding to the voltage of the electric current that flows through coil L1, i.e. the voltage at resistor R 7 two ends is transported to anti-phase (-) end of operational amplifier OP5.When being higher than the voltage at resistor R 7 two ends by the voltage of multiplication MT output, operational amplifier OP5 export high level signal, and it passes through locking circuit G1 to G4, thereby makes transistor Q2 conducting.
On the other hand, when the pulse signal of input operational amplifier OP4 noninverting (+) end was in low level state, transistor Q2 was in conducting state, flow through coil L1 electric current and increased gradually thereby make.When the electric current that flows through coil L1 was reached for the represented amplitude of the voltage of multiplier output, transistor was cut off thereupon.Subsequently, locking circuit G1 to G4 makes transistor Q2 be in cut-off state until the electric current vanishing of flowing through coil L1.By repeating aforesaid operations, can make electric current and voltage homophase, thereby proofread and correct power factor.
Prevent in the part 150 in overcurrent, coil T2 detects the electric current that flows through discharge lamp LAMP, voltage conversion circuit R12, D4, R13 and C4 are transformed into correspondent voltage E5 with it, and subsequently the voltage signal E5 after the conversion are delivered to noninverting (+) end of operational amplifier OP6.When voltage E5 is higher than preset reference voltage Vref 2, that is, when the judged result of step S130 was " YES ", operational amplifier OP6 had reduced the current potential that A is ordered, thereby transistor Q4 is ended.Therefore, make overcurrent can not flow through discharge lamp LAMP.
Claims (3)
1. the automatic illumination intensity control apparatus of a discharge lamp is characterized in that, comprising:
Discharge lamp;
Chopper circuit, it makes by AC mains being compressed into the direct voltage rising that capable rectification obtains;
Inverter circuit, it will be the alternating voltage with higher frequency by the dc voltage conversion of chopper circuit output, thereby drive described discharge lamp;
Be used for detecting the device of the brightness in zone to be illuminated;
Be used for being provided with the device of the brightness in zone to be illuminated;
When sensed luminance during, make the out-of-work device of described inverter circuit greater than set brightness.
2. control device as claimed in claim 1 is characterized in that, described control device also comprise when sensed luminance be proportional to set brightness during less than set brightness and detect brightness between difference change device by the voltage of chopper output.
3. control device as claimed in claim 1 or 2 is characterized in that, described control device also comprises the device that detects the current value that flows through described discharge lamp; With
When the current value that detects makes the out-of-work device of described inverter during greater than reference current value automatically.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 94116324 CN1120798A (en) | 1994-10-11 | 1994-10-11 | Automatic illumination intensity control apparatus for a discharge lamp |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 94116324 CN1120798A (en) | 1994-10-11 | 1994-10-11 | Automatic illumination intensity control apparatus for a discharge lamp |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1120798A true CN1120798A (en) | 1996-04-17 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 94116324 Pending CN1120798A (en) | 1994-10-11 | 1994-10-11 | Automatic illumination intensity control apparatus for a discharge lamp |
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| CN (1) | CN1120798A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100544537C (en) * | 2003-12-22 | 2009-09-23 | 松下电工株式会社 | Lighting apparatus for discharge lamp and lighting apparatus |
| CN103561241A (en) * | 2013-11-11 | 2014-02-05 | 山东神戎电子股份有限公司 | Power adjustment method of laser night-vision device |
-
1994
- 1994-10-11 CN CN 94116324 patent/CN1120798A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100544537C (en) * | 2003-12-22 | 2009-09-23 | 松下电工株式会社 | Lighting apparatus for discharge lamp and lighting apparatus |
| CN103561241A (en) * | 2013-11-11 | 2014-02-05 | 山东神戎电子股份有限公司 | Power adjustment method of laser night-vision device |
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