[0001] The present invention relates to an ion-generating circuit, especially an ion-generating circuit capable of adjusting ion amount.

[0002] Conventional positive and negative ions (plasma) generating circuit utilizes discharge diode (Diode For Alternating Current, DIAC), wherein discharge diode (DIAC) and Triad AC semiconductor switch (TRIAC) are combined to produce positive and negative high voltages, and then produce positive and negative ions via corona discharge. So the amount of positive and negative ions directly relates to the voltage of corona discharge is determined by trigger voltage of discharge diode in the conventional ion-generating circuit. However, the trigger voltage of a discharge diode is usually not constant (inconsistent) (at least 10% variation range is possible as given in the specification by the manufacturer), and it is difficult to control the amount of ions.

[0003] It would thus be desirable to have an ion-generating circuit capable of reliably adjusting the ion amount, having a consistent output voltage and stable ions output.

[0004] The inventors found that with the present invention as described and claimed herein, the disadvantages of the prior art can be overcome, in particular by providing an ion-generating circuit capable of reliably adjusting the ion amount, having a consistent output voltage and stable ions output as given herein.

[0005] Therefore the invention relates to an ion-generating circuit capable of adjusting ion amount which comprises a first voltage boost circuit, a second voltage boost circuit and a controller that controls the first voltage boost circuit and the second voltage boost circuit, respectively. The second voltage boost circuit comprises a references control circuit, a resonant discharge circuit and a second transformer, wherein the resonant discharge circuit comprises a first capacitor, a first inductor and a TRIAC (Triad AC semiconductor switch), which form a circuit together with a primary winding of the second transformer. One end of the primary winding of the second trans- former is connected to ground while the other end is connected to the first inductor. The first voltage boost circuit outputs voltage to the second voltage boost circuit and the references control circuit controls the TRIAC conduction according to the output voltage of the first voltage boost circuit. A secondary winding of the second transformer is connected to positive and negative ions corona discharge needles.

[0006] Further, the first voltage boost circuit comprises a first transformer, wherein one end of its secondary winding is connected to ground and the other end thereof is connected to a third diode, a sixth resistor, an eighth resistor and ground wire of the second voltage boost circuit in series. The first capacitor is connected to an intersection of the sixth resistor and the cathode of the third diode. The references control circuit also comprises a reference control chip, a ninth resistor, a PNP triode, a tenth resistor and an eleventh resistor, wherein the emitter of the PNP triode is connected to a first control voltage, the base of the PNP triode is connected to the first control voltage via the ninth resistor and the collector of the PNP triode is connected to the tenth resistor and the eleventh resistor in series, then to ground. The gate of the TRIAC is connected to the intersection of the tenth resistor and the eleventh resistor. The reference control chip takes the voltage on the intersection of the sixth resistor and the eighth resistor as its trigger voltage, the output terminal of the TRIAC is connected to the base of the PNP triode.

[0007] Further, the first voltage boost circuit also comprises a first resistor connecting to one end of the primary winding of the first transformer, and an NPN triode wherein its collector is connected to the other end of the primary winding of the first transformer, its emitter is connected to ground and its base is connected to the controller via a fourteenth resistor and a second resistor connected in series. The other end of the first resistor is connected to ground via a third capacitor and to a second control voltage via a second diode. [0008] Further, a third resistor is configured between two intersections, i.e. the intersection of the primary winding of the first transformer and the first resistor, and the intersection of the second resistor and the fourteenth resistor. The latter intersection is connected to ground via a Zener diode.

[0009] Further, the first transformer also comprises an auxiliary winding coupling with its secondary winding. One end of the auxiliary winding is connected to ground and the other end thereof is connected to the intersection of the second resistor and the fourteenth resistor via a positive feedback unit. [0010] Further, the positive feedback unit comprises a fourth capacitor, a fifth resistor and a thirteenth resistor, wherein the fourth capacitor and the fifth resistor are connected in series and then they are connected with the thirteenth resistor in parallel.

[0011] Further, the intersection of the sixth resistor and the eighth resistor is connected to the controller via the fourth resistor.

[0012] Further, the intersection of the first inductor and the primary winding of the second transformer is connected to the fourth resistor via a compensation circuit. The compensation circuit comprises a fourth diode whose anode is connected to the intersection of the first inductor and the primary winding of the second transformer while whose cathode is connected to ground via the second capacitor, and a seventh resistor connecting to the cathode of the fourth diode and the fourth resistor respectively.

[0013] Further, the collector of the PNP triode is connected to the controller via a twelfth resistor.

[0014] Further, the controller is a micro-programmed control unit (MCU) or a potentiometer.

[0015] Comparing with the prior art, the advantages of the present invention are as follows: [0016] The ion-generating circuit according to the present invention removes the discharge diode (DIAC) with poor consistency of trigger voltage, and employs a highly precision reference voltage (within the error of 1 %), whereby both consistency of output voltage and stability of ions are enhanced.

[0017] The invention also uses a MCU or a potentiometer on the output end of the fourth resistor to control the voltage on the intersection of the sixth resistor and the eighth resistor, thereby to control the trigger voltage of the reference control circuit, and then control the resonant discharge circuit, such that the ion amount can be controlled conveniently. The present invention actually has the function of AIT ion circuit.

[0018] Trigger scenario in the reference control circuit can be detected by the twelfth resistor and fed back to the controller, whereby the discharge frequency of the ion-generating circuit is calculated and then the trigger power of the reference control circuit is adjusted via the second resistor, thus the discharge frequency of the ion-generating circuit can be steady and adjustable.

[0019] FIG.1 is a circuit diagram of the ion-generating circuit according to the present invention.

[0020] FIG.2 is an oscillogram of V1 in FIG.1 .

[0021 ] FIG.3 is an oscillogram of V2 in FIG.1 . [0022] FIG.4 is an oscillogram of V3 in FIG.1 .

[0023] FIG.5 is an oscillogram relative to V1 and V3 synchronously in FIG.1 .

[0024] FIG.6 is an oscillogram relative to V1 and V2 synchronously in FIG.1 .

[0025] The present invention will be further described hereinafter with reference to the exemplary embodiment. However, the invention shall not be restricted to this embodiment.

[0026] As shown in FIG.1 , the ion-generating circuit comprises a controller M1 , a first voltage boost circuit and a second voltage boost circuit consisted of both positive and negative ion corona discharge needles and a circuit between a first transformer T1 and both needles. The first voltage boost circuit comprises the first transformer T1 and a circuit between the first transformer T1 and the controller M1 . The controller M1 outputs the control signal to the first voltage boost circuit and the second voltage boost circuit, to control the turn-on/cut-off of the energy transmission of the first voltage boost circuit and the storage/release of the energy of the second voltage boost circuit, wherein the released energy produces positive and negative ions in the positive and negative ions corona discharge needles respectively, by ionizing air. The second voltage boost circuit comprises a references control circuit, a resonant discharge circuit and a second transformer T2, wherein the resonant discharge circuit comprising a first capacitor C1 , a first inductor L1 and a TRIAC TR1. One end of the primary winding of the second transformer T2 is connected to ground and the other end thereof is connected to the first inductor L1. The references control circuit controls the TRIAC conduction in order to make the first capacitor C1 , the first inductor L1 , the primary winding of the second transformer T2 and the ground wire to form a loop to discharge, and to produce the resonance. The resonance voltage become higher after the second transformer T2, and will be output to positive and negative ions corona discharge needles via a first diode D1 and a fifth diode D5 respectively, to produce positive and negative ions.

[0027] The anode of the second diode D2 is connected to the input, and the cathode thereof is connected to the third capacitor C3 and the first resistor R1. Wherein the third capacitor C3 is connected to ground and the first resistor R1 is connected to one end of the primary winding of the first transformer T1 . When Alternating Current (AC) is input in VCC, AC is rectified to Direct Current (DC) by the second diode D2 and the third capacitor C3. When DC is input in VCC, the second diode D2 can protect components of the circuit from damage in case of DC reverse polarity. The DC is supplied to the first voltage boost circuit after the first resistor R1. An output end of the controller M1 can adjust the power of the first voltage boost circuit by using the second resistor R2, and the working principle is that the second resistor R2 is connected between the fourth pin of the controller M1 and the base of the NPN triode Q1 , the maximum current of the fourth/fifth pins of the transformer T1 is equivalent to the collector current l _c of the NPN triode Q1 , wherein ( IR2+ IR3 ) , β is a current enlargement factor of the triode. When the voltage on the fourth pin of controller M1 was raised, the current IR2 on the second resistor R2 increases, accordingly the maximum current on the fourth/fifth pins of the transformer T1 increase, the output power of the transformer T1 also increases. Similarly, when the voltage on the fourth pin of controller M1 decreased, the maximum current on the fourth/fifth pins decrease, and the output power of the transformer T1 decreases correspondingly. The first voltage boost circuit outputs current rectified by the third diode D3, to the second voltage boost current, thus voltage V1 is the input voltage of the second voltage boost circuit and the maximum voltage of the first voltage boost circuit is the trigger voltage of the second voltage boost circuit.

[0028] As shown in FI G.1 , the auxiliary winding of the first transformer T1 acts as a positive feedback loop of the first voltage boost circuit. The thirteenth resistor R13 provides a positive feedback signal to the NPN triode Q1 , and the fifth resistor R5 and the fourth resistor R4 act as an acceleration switch circuit of the NPN triode Q1 , in order to speed up the turn-on/cut-off of the NPN triode Q1 and improve efficiency of the first voltage boost circuit.

[0029] The third resistor R3 acts as an actuating resistor of the self-oscillated circuit consisting of the NPN triode Q1 and the first transformerTI . The Zener diode ZD1 acts as a amplitude-limited Zener diode of the NPN triode Q1 to prevent the NPN triode Q1 from damage due to overvoltage output from the fourth pin of the controller M1 , and also acts as a discharge loop of the fourth capacitor C4.

[0030] The output voltage V1 of the first voltage boost circuit is distributed on the sixth resistor R6 and the eighth resistor R8, and the voltage on the intersection of the sixth resistor R6 and the eighth resistor R8 is inputted to a reference control chip IC1 in the references control circuit, to compare with the reference voltage predetermined in IC1 . When IC1 is model TL431 , the internal reference voltage is 2.5V±1 %. Once the voltage on the intersection exceeds the reference voltage in IC1 , IC1 is connected to the base of the PNP triode Q2 and outputs low voltage so as to make the PNP triode Q2 turn-on. After that, the voltage on the collector of the PNP triode Q2 turns to high voltage and triggers the TRIAC TR1 . The first capacitor C1 , the TRIAC TR1 , the first inductor L1 and the primary winding of the second transformer T2 form the loop to discharge and produce resonance. Meanwhile the TRIAC TR1 uses the third diode D3 to short-circuit the output end, i.e. the secondary winding, of the first transformer T1 in the first voltage boost circuit. Consequently the positive feedback winding, i.e. the auxiliary winding, of the first transformer T1 does not produce positive feedback voltage between the pin 1 and pin 2, and the first voltage boost circuit does not work. The TRIAC TR1 turns to be cut-off in the case of the current on it being less than its holding current when the energy storage in the first capacitor C1 is consumed over. Then the first voltage boost circuit starts working under the action of the third resistor R3 which acts as the actuating resistor, and the output voltage V1 increases. Such process above is repeated to realize the voltage boost/cut-off of the first voltage boost circuit and the energy storage/release of the second voltage boost circuit.

[0031] The fourth diode D4, the second capacitor C2 and the seventh resistor R7 form a sampling and holding circuit for the input voltage V1 on the primary winding of the second transformer T2 to compensate the discrepancy of output voltage caused by capacitance error of the first capacitor C1 . The first voltage boost circuit charges the first capacitor C1 with its output energy and the energy for the second voltage boost circuit is stored in the first capacitor C1 . In the case of certain voltage, the bigger the capacitance of the first capacitor C1 , the more energy storage it has, the greater amplitude of the LC resonance a LC circuit has, the LC circuit is consisted of the first capacitor C1 , the first inductor L1 and the primary winding of the second transformer T2, and the higher discharge voltage the positive and negative ions corona discharge needles have, when the voltage was coupled by the second transformer T2 and rectified by the first diode D1 and the fifth diode D5. Similarly, the smaller the capacitance of the first capacitor C1 , the lower discharge voltage the positive and negative ions corona discharge needles have. Its working principle is that the bigger the capacitance of the first capacitor C1 , the higher resonance voltage the LC circuit has, the LC circuit is consisted of the first capacitor C1 , the first inductor L1 and the primary winding of the second transformer T2. After the resonance voltage was rectified by the fourth diode, the voltage on the second capacitor C2 is higher, and the voltage fed back to the reference control chip IC1 via the seventh resistor R7 is going higher. In this circuit diagram, IC1 uses model TL431 in which a reference voltage and a comparator are integrated.

[0032] The ion-generating circuit is able to adjust the voltage V1 by a MCU or an external potentiometer acting as a controller on output end of R4, and thereby control the trigger voltage for the second voltage boost circuit, that is, the ion amount discharged can be dominated easily by controlling the amplitude of the voltages V1 and V2. The circuit also has the function of air ion tester (AIT), which can detect the amount of ions according the discharge voltage.

[0033] As shown in FIG.1 , the branch circuit on which the twelfth resistor R12 located can detect the synchronous signal to trigger the TRIAC TR1 . The signal output from the PNP triode Q2 is output to the controller M1 via the twelfth resistor R12 to detect the trigger frequency of the TRIAC TR1 . When the trigger frequency was too high, the voltage on the fourth pin of the controller M1 can be decreased to reduce the power of the first voltage boost circuit and stabilize the trigger frequency of the TRIAC TR1 . The output of the twelfth resistor R12 is a narrow pulse waveform. The discharge frequency of the second voltage boost circuit outputs through the twelfth resistor R12, and is detected by an external MCU or a circuit, and then the power of the first voltage boost circuit can be adjusted by changing the value of the second resistor R2. Meanwhile the trigger interval time of the voltages between V1 and V2 can be adjusted, whereby the discharge frequency of the second voltage boost circuit can be adjusted and stabilized accordingly.

[0034] As shown in FIG.2, the voltage V1 goes through the cyclic process of boost/cut-off. It can be seen from FIG.3, the first capacitor C1 goes through the cyclic process of discharge/charge and makes the voltage V2 generate a corresponding waveform. It can be seen from FIG.4, the waveform diagram V3 reflects the status of the PNP triode Q2. It can be seen from FIG.5 the corresponding relationship between the voltages V1 and V3. When the voltage V1 was increasing, the first capacitor C1 is being charged, at that time, the PNP triode Q2 is cutoff and the corresponding voltage V3 is zero. Once the voltage V1 is high enough, the PNP triode Q2 is triggered and then the voltage V3 increases immediately. Because the resonance discharge loop starts working, the first voltage boost circuit approaches cutoff status, consequently, the voltage V1 approaches zero. In FIG.6, the diagram of the time-voltage relationship between V1 and V2 also reflects the configuration of circuit on FIG.1.

[0035] As shown in FIG.1 , the voltage output from the first voltage boost circuit, via the third diode D3, is marked as V1 . The voltage on the intersection of the first capacitor and the first inductor is marked as V2. The voltage on the collector of the PNP triode Q2 is marked as V3 when the PNP triode Q2 was turn-on. The voltage on the fourth pin of the controller M1 outputs is marked as V4. The voltage on the second pin of the controller M1 is marked as V5. If V5 is adjusted by an external volta e, the V1 is

[0037] if V5 is adjusted by an external resistor marked as RV5, the V1 is: [0039] In the present invention, the consistency of output voltage and the stability of ions are obviously enhanced by using high precision and steady reference voltage IC as trigger reference voltage, and additional compensating circuit.

[0040] The above description intends to explain the preferred embodiments only, rather than making any limitation to the invention. Any alternation, change or modification related to the invention in the same general inventive concept may be incorporated into ambit of claims of the present invention.