JP3274370B2 - Power supply circuits for air purifiers, etc. - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply circuit for a household electric appliance such as an air purifier and the like, and more particularly, to preventing a malfunction of a device controlled by remote control.

[0002]

2. Description of the Related Art An air purifier includes an electric dust collector using a DC high voltage power supply (6 kV). Therefore, a high voltage power supply obtained by converting a commercial power supply to a DC high voltage is used, and a light receiving element for remote operation and the like are used. For driving the various control elements, a low-voltage power supply obtained by converting a commercial power supply into a DC low voltage is used as usual.

The above high voltage power supply has a function of rectifying a commercial power supply, passing the same through a switching circuit, raising the frequency, and then boosting the voltage. In some cases, the signal is guided by a signal line of the element and is superimposed on a control signal flowing through the signal line, which causes a malfunction.

In order to prevent such a malfunction, conventionally, the light receiving element is moved away from the high-voltage power supply or the high-voltage supply lead as much as possible, or the light-receiving element and the microcomputer are brought close to each other so that the lead between them is connected. In order to shorten the length, measures such as mounting the light receiving element on a microcomputer board have been taken.

[0005]

However, the light receiving element cannot be mounted on the microcomputer substrate due to the design problem of the air purifier or the like and other viewpoints. May have to be placed in

It is therefore an object of the present invention to provide a power supply circuit which does not cause a malfunction due to induction of noise including harmonics even in such a case.

[0007]

In order to achieve the above object, the present invention comprises a DC high-voltage power supply and a low-voltage power supply,
In a power supply circuit such as an air purifier , the output of the high-voltage power supply is supplied to a desired internal device, and the output of the low-voltage power supply is supplied to various control elements such as a light-receiving element that is remotely controlled. Difference between the output side of the power supply and the low-voltage power supply
Connect the polar part through a coupling capacitor to
Noise generated by the power supply is used as
By applying the voltage to the low-voltage power supply through a capacitor,
Noise from the high-voltage power supply superimposed on the output line of the
The output of the high-voltage power supply and the low-voltage power supply.
Connect the same-polarity part of the
The noise generated by the high-voltage power supply is
By adding it to the low-voltage power supply through a capacitor,
The high-voltage power supply superimposed on the ground wire of the control element
This is to cancel the noise that occurs.

[0008] An embodiment for connecting the output side mutually the high-voltage power supply and low-voltage power source via the coupling capacitor, if the following times <br/> circuit condition A connection mode a, either b, also following In the case of the circuit condition B, the connection state is one of the connection modes c and d.

That is, [Circuit condition A] A case where noise appearing on the positive output side of the high voltage power supply is superimposed on the output line of the control element. Connection mode a: connecting the positive output terminal + V _L and the negative electrode output terminal -V _H of the high-voltage power supply of low voltage power supply via the coupling capacitor. The b: connecting the positive output terminal + V _H of the negative electrode output terminal -V _L and the high-voltage power supply of the low voltage power supply via the coupling capacitor. [Circuit Condition B] A case where noise appearing on the positive output side of the high voltage power supply is superimposed on the ground line of the control element. Connection mode c: The positive output terminal + V _{L of the} low-voltage power supply and the positive output terminal + V _H of the high-voltage power supply are connected via a coupling capacitor. The d: connecting the negative output terminal -V _L and the negative electrode output terminal -V _H of the high-voltage power supply of low voltage power supply via the coupling capacitor.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a power supply circuit of an air purifier, which has a low-voltage power supply 2 and a high-voltage power supply 3 connected in parallel to a commercial power supply 1. In the low-voltage power supply 2, the step-down transformer 4
A diode 5 and a smoothing capacitor 6 for converting to direct current are connected to the next side, and a positive electrode output terminal + V _{L of} low DC voltage,
The negative output terminal -V _L is provided. These outputs +
V _L, the light receiving element 7 other control element is connected between -V _L. The light receiving element 7 has an output line 7a and a ground line 7b, receives an infrared ray emitted from a remote control device, and inputs a required output signal to a microcomputer (not shown).

The high-voltage power supply 3 has a step-up transformer 8.
A rectifying diode 9 and a switching element 10 are connected in series to the primary side. The above switching element 10
Oscillation circuit 16 for driving is connected to, thereby by turning on and off the primary side input, converts the rectified DC to AC of a frequency higher than the frequency of the commercial power source 1, a transformer 8 It is added to the primary side. By increasing the frequency on the primary side, the size of the step-up transformer 8 is reduced. A rectifying diode 11 and a smoothing capacitor 12 are connected to the secondary side, and a DC high-voltage positive output terminal + V _H and a negative output terminal -V _H are provided.

[0013] the secondary side of the low-voltage power source 2 and the high voltage power supply 3 described above, conventionally had been respectively separate and independent, in the present invention, the output end of the low-voltage power supply 2 + V _L, of -V _L and the high voltage power supply 3 The output terminals + V _H and −V _H are connected to each other via a coupling capacitor 13 having a capacitance (for example, 0.1 μF) in a required connection manner according to circuit conditions.

The coupling capacitor 13 is connected to the low-voltage power supply 2
And the output side of the high-voltage power supply 3 are maintained in a separated and independent relationship in the same manner as in the prior art, but are energized in the alternating current.

The coupling capacitor 13 is connected to each of the output terminals + V _L and -V _L of the low-voltage power supply 2 and each of the output terminals of the high-voltage power supply 3 +
V _H, the mode of connection between -V _H, FIG. 1 (a),
There are connection modes a to d shown in FIG. That is, the connection mode a is, + V _L and between -V _H, between the b is -V _L and + V _H, between the c is + V _L and + V _H, the d is -V _L and -V _H
Between. Any of these connection modes a to d is appropriately selected according to the following circuit conditions A or B.

[Circuit Condition A] The circuit condition A is determined by the light receiving element 7
In this case, the noise appearing at the positive output terminal + V _H of the high-voltage power supply 3 is superimposed on the output line 7a due to circuit conditions such as the output line 7a being formed long or approaching the high-voltage power supply 3. In this case, either connection mode a or b is adopted.

FIG. 2A shows the principle of canceling the influence of noise when the connection mode a is adopted. In this figure,
N is the induction noise superimposed on the output line 7a, S is an ideal signal unaffected by the induction noise N, S 'is a signal deformed under the influence of the induction noise N, and the negative output terminal of the high-voltage power supply.
Through the coupling capacitor 13 is outputted from the V _H the compensation noise added to the positive output terminal + V _L of the low voltage power supply represents N _C, the signal after compensation in S _C.

As described above, the induction noise N is a nozzle appearing at the positive output terminal + V _H of the high voltage source 3, whereas the compensation nozzle N _C is connected to the negative output terminal −V of the same high voltage source 3. This is the noise that appears at V _H , both of the same magnitude but of opposite phase.

Therefore, the above-mentioned guide nozzle N is superimposed on the high level side of the signal S (indicated by a + sign in the figure).
Then, as shown by the arrow, the signal S ′ is deformed into a shape in which the induction noise N is superimposed on the high level side. When the compensating nozzle N _C added to the positive electrode output terminal + _VL is superimposed on this deformed signal S ′ (indicated by a + symbol in the figure), the compensation nozzle N cancels out the component as shown by the arrow. signal S _C is obtained.

FIG. 2B shows the principle of canceling the influence of noise when the connection mode b is adopted. In this case, the process is the same as that described above until the induction nozzle N is superimposed on the high-level portion of the signal S to become the signal S ′, but the compensation noise N _C that appears at the positive output terminal + V _H of the high-voltage power supply 3 is , that it is induced noise N in phase, and its compensation nozzle N _C is different is that applied to the negative output terminal -V _L of the low-voltage power supply 2. Therefore, the compensated signal S _C in this case is in a state where noises of the same phase and the same magnitude are superimposed on the high level and the low level, respectively. Since the difference between the high level and the low level of such a signal is constant, the microcomputer can treat the same signal as a rectangular signal.

Which of the above connection modes a and b is adopted is appropriately determined based on circuit design conditions such as shortening of the connection circuit of the coupling capacitor 13.

[Circuit Condition B] Next, the case of the circuit condition B will be described. In this case, the ground line 7b of the light receiving element 7
Is formed long or the noise appearing at the positive output terminal + V _H of the high voltage power supply 3 is superimposed on the ground line 7b due to circuit conditions such as approaching the high voltage power supply 3. In this case, one of the connection modes c and d is adopted.

FIG. 2C shows the principle of canceling the influence of noise when the connection mode c is adopted. In this case, since the induction nozzle N is superimposed on the ground line 7b, it is added to the low level side of the signal S. When the low level is used as a reference, the signal S 'is inverted to the high level side as shown in FIG. Becomes the same signal S ′ as when superimposed. Such signal S ', when compensated nozzle N _C from the positive output terminal + V _H of the high-voltage power supply 3 is applied to the positive output terminal + V _L of the low voltage power source 2, the signal S' induction noise component of is canceled, the compensation signal S _C
Is obtained.

In the case of the connection mode d is, until the signal S 'is obtained, it is the same as that in the connection mode c, compensation nozzles Nc appearing on the negative electrode output terminal -V _H of the high-voltage power supply 3,
It has the opposite phase to the induction nozzle, and changes the low level of the signal S 'in the opposite phase. Since the difference between the high level and the low level of the signal S 'is constant, the microcomputer can treat the signal S' in the same manner as a rectangular signal.

The above is the noise appearing at the positive output + V _H of the high-voltage power source 3 becomes inductive noise N, is a method of compensating for couple to the low-voltage power supply 2 side, the negative output -V _H of the high-voltage power supply 3 The case where the appearing noise is induced to the low voltage power supply 2 side can be similarly compensated. When the circuit conditions A and B are both present, the connection modes a or b and c
Alternatively, the compensation can be similarly performed by employing a combination of d.

[0026]

As described above, according to the present invention, when noise generated on the high voltage power supply side is guided to the low voltage power supply side, the noise is generated from the high voltage power supply side, which is the source of the noise, to the low voltage power supply side through the coupling capacitor. Since the noise is applied to the low-voltage power supply side as compensation noise, and the compensation noise cancels out the induction noise, malfunction of the device due to the influence of noise generated in the high-voltage power supply can be eliminated.

[Brief description of the drawings]

FIG. 1A is a circuit diagram of an embodiment. FIG. 1B is a circuit diagram showing a part of another embodiment.

FIGS. 2A to 2D are explanatory diagrams of noise compensation principles;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Commercial power supply 2 Low voltage power supply 3 High voltage power supply 4 Transformer 5 Diode 6 Smoothing capacitor 7 Light receiving element 8 Transformer 9 Diode 10 Switching element 11 Diode 12 Smoothing capacitor 13 Coupling capacitor

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Tadashi Nomura 1-20-5 Tenma, Kita-ku, Osaka-shi Zojirushi Ma Hobin Co., Ltd. (56) References JP-A-3-109954 (JP, A) 52-45885 (JP, U) Actually open 1987-72150 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B03C 3/00-3/88 H02J 1/00-1 / 16

Claims (2)

(57) [Claims] 1. A high-voltage power supply and a low-voltage power supply for direct current, the output of the high-voltage power supply is supplied to a desired internal device, and the output of the low-voltage power supply is supplied to various control elements such as a light-receiving element that is remotely operated. In a power supply circuit such as an air purifier, different polarity parts on the output side of the high-voltage power supply and the low-voltage power supply
Connected via a coupling capacitor, and
Generated noise as compensation noise
Output to the low-voltage power supply through
Noise generated by the high-voltage power supply superimposed on the power line
So that the output of the high-voltage power supply and the low-voltage power supply
Connect the polar part through a coupling capacitor to
Noise generated by the power supply is used as
By applying the voltage to the low-voltage power supply through a capacitor,
A power supply circuit for an air purifier or the like, wherein noise generated by using the high-voltage power supply superimposed on a ground line of a child is canceled. 2. A manner between the output side mutually the high-voltage power supply and low-voltage power supply connected via the coupling capacitor, in the case of <br/> circuit condition A below connection mode a, either b, also The power supply circuit for an air purifier or the like according to claim 1, wherein one of the connection modes c and d is adopted in the case of the following circuit condition B. [Circuit Condition A] The case where noise appearing on the positive output side of the high voltage power supply is superimposed on the output line of the control element. Connection mode a: connecting the positive output terminal + V _L and the negative electrode output terminal -V _H of the high-voltage power supply of low voltage power supply via the coupling capacitor. The b: connecting the positive output terminal + V _H of the negative electrode output terminal -V _L and the high-voltage power supply of the low voltage power supply via the coupling capacitor. [Circuit Condition B] A case where noise appearing on the positive output side of the high voltage power supply is superimposed on the ground line of the control element. Connection mode c: The positive output terminal + V _{L of the} low-voltage power supply and the positive output terminal + V _H of the high-voltage power supply are connected via a coupling capacitor. The d: connecting the negative output terminal -V _L and the negative electrode output terminal -V _H of the high-voltage power supply of low voltage power supply via the coupling capacitor.