JPH0622541A - Control power supply - Google Patents

Abstract

PURPOSE:To provide a control power device which can control an overload current when the power is turned on and which requires only a short time for stabilizing a load current. CONSTITUTION:When the power is turned on, a resistance of a lamp LMP is small and so a load current IL is large. Then, an output of an output current detecting circuit 2 is supplied to a PWM controlling circuit 3 through an OR circuit 4 and a transistor Tr1, a switching element, is intermittently controlled to hold down the load current IL. When the lamp LMP increases its resistance due to generation of heat, an output of an output voltage detecting circuit 1 is selected by the OR circuit 4 and then is supplied to the PWM controlling circuit 3 and the transistor Tr1 is intermittently controlled for stabilization of a load voltage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control power supply device for supplying power to a load such as a halogen lamp, which has a relatively large inrush current when the power is turned on or when the power is turned on again.

[0002]

2. Description of the Related Art Conventionally, a phase control method using a thyristor or a triac has been used as a general control method for an exposure halogen lamp of a copying machine or a lamp regulator used in a projector. As shown in FIG. 11, this phase control system is a control system in which the switching element controls the on period in each half cycle of the commercial frequency to adjust the power supply to the load.
For example, when increasing the luminous flux of the lamp which is the load, the conduction period is lengthened to θ1 and θ2, and when the power supply to the load is suppressed, that is, when the luminous flux is narrowed, the conduction period is θ3 and θ2.
It is a method of adjustment such as shortening to 4.

FIG. 13 shows a circuit configuration of a conventional general lamp regulator. The voltage applied to the lamp is detected by the step-down transformer (feedback transformer) TL, and the output thereof is input to the control circuit, whereby the transistor Tr1 is turned on and its output is input as the gate signal of the triac T1 through the pulse transformer Ts. , Triac T1 triggers. The power output, that is, the light flux control is performed by repeating that the value output thereby is detected by the feedback transformer TL.

[0004]

However, in the case of a load such as a lamp having a characteristic that the resistance value is low at the moment of lighting, and then heats up to stabilize the resistance value,
In the power control (usually constant voltage control) like the conventional example of 3, the large inrush current of about 10 times the steady current flows when the power is turned on, and not only the lamp life is shortened by this repetition, but also it is used. This causes heat generation of a switching element such as a triac, which is a cause of accelerating its deterioration.

Therefore, in the conventional control power supply, as a method for preventing such an inrush current, a method of preliminarily supplying a minute current to the lamp to preheat it, and a phase angle αi at power-on in phase control are shown in FIG. As shown, a so-called soft start method has been used in which the voltage is gradually increased, that is, the voltage applied to the lamp is gradually increased to suppress the inrush current, but in the former case, current always flows through the lamp. The efficiency is poor, and the latter has a problem that it takes time to stabilize the voltage when the inrush current is suppressed to a small level.

Further, in the case of the phase control, there is a problem that the switching frequency cannot be increased when the fluctuation of the luminous flux causes a problem in the luminous flux control or the like. As a countermeasure against this, there is a high frequency lighting that converts a DC power supply into a high frequency, but in this case a rectifier circuit is required. However, in the conventional rectifier circuit, a capacitor input type rectifier circuit is often used because of its economical efficiency, and the line current input during the rectifying operation is the same as that of the smoothing capacitor as shown in FIG. A large value flows in a pulse shape only during the charging period, which causes a decrease in power factor and current waveform distortion due to harmonic current flowing to the commercial power line, and noise due to harmonic components may cause malfunction between electronic devices. There is also a problem that the life of the capacitor itself is shortened due to heat generation due to internal loss.

The present invention has been made to solve such a problem, and an object thereof is to provide a control power supply device which can suppress an overload current at the time of turning on the power supply and has a short load current stabilization time. It is what

[0008]

In order to achieve the above-mentioned object, in the present invention, the control power supply device is constructed as in the following (1) to (7).

(1) Output current detecting means, output voltage detecting means, selecting means for selecting an output of the output current detecting means and output of the output voltage detecting means, whichever has a larger value, and the control power supply. A control power supply device comprising: a switching element for connecting / disconnecting a main circuit of the apparatus; and a control unit for controlling the switching element according to an output of the selecting unit.

(2) The control power supply device according to (1), further comprising an input voltage detecting means and a correcting means for correcting the output of the output current detecting means by the output of the input voltage detecting means.

(3) A light flux detecting means for detecting a light flux of a lamp which is a load, and a detection level setting means for setting a detection level of the output current detecting means according to an output of the light flux detecting means. 1) The control power supply device described.

(4) A control power supply device having an input stage and an output stage, wherein the input stage includes a rectifying circuit, an AC input voltage waveform detecting means for detecting a waveform of an AC input voltage of the rectifying circuit, and A first switching element that connects and disconnects the main circuit of the input stage, a first output current detection unit that detects an output current of the input stage, and an output waveform of the first output current detection unit is the AC input voltage waveform. First control means for intermittently controlling the first switching element so as to approximate the output waveform of the detection means, and the output stage includes second output current detection means for detecting the output current of the output stage. An output voltage detecting means for detecting an output voltage of the output stage, a selecting means for selecting an output having a larger value from outputs of the second output current detecting means and the output voltage detecting means; No.1 to interrupt the main circuit Control power supply device including a switching element, and a second control means for intermittently controlling said second switching element in response to an output of said selection means.

(5) The control power supply device according to (4), wherein one control means is switched in a time division manner to serve as the first control means and the second control means.

(6) It further comprises a second output voltage detecting means for detecting the output voltage of the input stage, and operates the first control means so that the output level of the second output voltage detecting means becomes constant. (4) The control power supply device as described above.

(7) A luminous flux detecting means for detecting the luminous flux of the lamp which is a load, and a second luminous flux detecting means in accordance with the output of the luminous flux detecting means.
6. The control power supply device according to (4), further comprising: detection level setting means for setting the detection level of the output current detection means.

[0016]

In the configurations (1) to (3), the output becomes constant current / constant voltage due to the intermittent control of the switching element.
In the configurations of (4) to (7), the waveform of the AC input current of the control power supply device approximates to the waveform of the AC input voltage due to the control interruption of the first switching element in addition to the above-described operation.

[0017]

EXAMPLES The present invention will be described in detail below with reference to examples.

(Embodiment 1) FIG. 1 is a circuit diagram of a "control power supply device" which is Embodiment 1. In FIG.

As shown in the figure, in this embodiment, the current detection resistor Ri, the transistor Tr1, the free wheeling diode D5,
Choke coil L1, lamp LMP, output voltage detection circuit 1, output current detection circuit 2, PWM circuit 3, OR circuit 4,
The lighting control circuit 5 is used.

The commercial frequency power source connected to the power source input terminal is rectified by the rectifying bridge (diodes D1 to D4), smoothed by the capacitor C1 and supplied to the collector of the transistor Tr1. Transistor T
The alternating current output generated at the emitter due to the interruption of r1 is smoothed by the smoothing circuit composed of the choke coil L1 and the capacitor C2, and is supplied to the lamp LMP which is a load via the current detection resistor Ri. Here, ON / OFF of the lighting of the lamp is controlled by the lighting control circuit 5.

When a control signal for lighting the lamp is issued to the PWM control circuit 3 by the lighting control circuit 5, the PWM control circuit 3 is determined based on the detection signals from the output current detection circuit 2 and the output voltage detection circuit 1. Transistor Tr
Turn on 1. When the transistor Tr1 is turned on, a current IL flows into the circuit, a potential difference is generated across the current detection resistor Ri, and the value is input to the output current detection circuit 2. The voltage VLMP supplied to the lamp LMP is divided by the resistors R1 and R2 and input to the output voltage detection circuit 1. When the detected values are input to the output current detection circuit 2 and the output voltage detection circuit 1, a detection signal corresponding to each value is generated and output to the OR circuit 4.

The OR circuit 4 detects P of the detection signal output from the output current detection circuit 2 and the output voltage detection circuit 1.
The priority order input to the WM circuit 3 is determined by the height of those voltage levels. That is, as shown in (a) of FIG. 2, since the resistance value of the halogen lamp is low at the start of lighting, the flowing current becomes large. Therefore, as shown in (b) of FIG. By setting the voltage level to be higher than the voltage level of the output voltage detection signal in advance, the detection signal from the output current detection circuit 2 is prioritized, and the control power supply device performs constant current control. When the resistance value of the halogen lamp LMP becomes stable as the temperature rises, the current value becomes low. Therefore, in the PWM control circuit 3, as shown in FIG. The voltage value output from the output voltage detection circuit 1 becomes larger than the voltage value that is generated, and the control shifts to the constant voltage control.

The above operation is performed every pulse, that is, every time the transistor Tr1 is turned on. This makes the lamp L
The inrush current to the MP is limited by the constant current control, and then the voltage is shifted to the constant voltage control in a short time to perform stable control of the luminous flux (so-called light amount).

As described above, according to the present embodiment, in a circuit for supplying electric power to a lamp load that causes a large inrush current, a so-called light amount control circuit, etc., the inrush current at the time of lighting the lamp is limited while rising. The time can be shortened and the stress on the switching element can be reduced.

Although a resistor is used for current detection in this embodiment, a current transformer may be used instead.

(Second Embodiment) FIG. 3 is a circuit diagram of the second embodiment. The circuit configuration of this embodiment is almost the same as that of the first embodiment.
The only difference is that an input voltage detection unit 6 that detects the voltage on the input side of the switching element Tr1 is provided so that the detection level by the current detection resistor Ri does not change due to changes in the input voltage.

That is, the input voltage detector 6 corrects the voltage drop in the current detection resistor Ri in accordance with the input voltage,
The control power supply is not affected by input fluctuations. Other operations are the same as those in the first embodiment.

(Embodiment 3) A third embodiment shown in FIG. 4 has substantially the same circuit configuration as that of the first embodiment, and an output current detection circuit 2
-2, only the portion where the offset signal given from the CPU (central processing unit) 7 on the equipment main body side instead of the Zener diode ZD1 that determines the current detection level and the light flux reading portion 8 of the lamp LMP are added. Be different.

With this configuration, the lamp LMP
The current detection level is controlled by the CPU 7 so that the time until the luminous flux is stabilized and the current detection level are mutually optimal values.

Further, if fuzzy control, neuro control, or the like, which has come to be used in many home electric appliances at present, is used for this detection level control by including not only the light flux but also parameters such as the heat generation amount of the switching element, it is more optimal. Various controls are possible.

(Fourth Embodiment) A fourth embodiment will be described. The present embodiment is an example in which the above control power supply device is used as a power supply for a load having a low average current with respect to a peak current such as a motor load. If this control power supply is applied to the power supply of a motor load, it works as a constant current control circuit when the peak current becomes large to suppress the peak current and reduce the stress on the switching element. It becomes possible to design heat dissipation plates, transformers, and switching elements, which had to be done, with average current.

(Embodiment 5) FIG. 5 is a circuit diagram of a "control power supply device" which is Embodiment 5. In FIG. As shown in the figure, the device of this embodiment is roughly divided into a part forming an SMR control circuit in an input stage and a part forming a constant current / constant voltage control circuit in an output stage.

The part constituting the SMR, that is, the input stage is
Diode Ds, transistor Ts, current detector 31,
It is composed of a choke coil Ls, a capacitor Cs, an AC input voltage waveform detection circuit 32, a multiplication circuit 33, a subtraction circuit 34, an amplification circuit 35, and a PWM control circuit 36. Constant current
The part constituting the constant voltage control circuit, that is, the output stage, includes a transistor T1, a current detection resistor Ri, and an output voltage detection circuit 3
7, output current detection circuit 38, PWM control circuit 36, OR
Circuit 39, lighting control circuit 40, clock 41 used for it and time division control, analog switch 42, latch 4
It is composed of 3,44.

First, the operation of the input stage will be described. The commercial frequency power source connected to the power source input terminal is rectified by the rectifying bridge (diodes D1 to D4) and supplied to the collector of the transistor Ts via the choke coil Ls. Capacitor C due to the interruption of transistor Ts
A current shaped into a waveform similar to the input voltage waveform is charged in s via the diode Ds. Transistor Ts
The current waveform generated by the intermittent connection of the current is detected by the current detection unit 31 and output to the subtraction circuit 34. Also, the subtraction circuit 34
In order to change the peak value of the waveform data obtained by the AC input voltage waveform detection circuit 32 according to the load current, the multiplication circuit 3
The value via 3 is entered. Subtraction circuit 34, amplification circuit 3
The error of the two input values is amplified by 5, and the PWM control circuit 3
By inputting the signal to the transistor 6, the on / off control of the transistor Ts is controlled so that the current waveform becomes a waveform similar to the AC input voltage waveform as shown in FIG. 7B.

Next, the operation of the output stage will be described. The DC output obtained at the input stage is converted into an AC output generated at the emitter by the interruption of the transistor T1, and this output is smoothed by the smoothing circuit composed of the choke coil L1 and the capacitor C2, and the lamp is output via the current detection resistor Ri. LMP
Is supplied to. Here, ON / OFF of the lighting of the lamp LMP is controlled by the lighting control circuit 40.

When the lighting control circuit 40 outputs a control signal for lighting the lamp to the PWM control circuit 36, it is determined based on the detection signals from the PWM control circuit 36, the output current detection circuit 38, and the output voltage detection circuit 37. The transistor T1 is turned on only for a certain period. When the transistor T1 is turned on, the current IL flows into the main circuit, and the current detection resistor Ri
A potential difference is generated at both ends of the output current and the value is input to the output current detection circuit 38. The voltage supplied to the lamp LMP is divided by the resistors R1 and R2 and input to the output voltage detection circuit 37. Output current detection circuit 38, output voltage detection circuit 37
The signal detected at is output to the OR circuit 39.

By the OR circuit 39, the priority order of the detection signals output from the output current detection circuit 38 and the output voltage detection circuit 37 to be input to the PWM control circuit 36 is determined by their potential levels. . That is, FIG.
As shown in (a) of FIG. 3, since the resistance value of the halogen lamp LMP is low at the start of lighting, the flowing current becomes large. Therefore, as shown in (b) of the same figure, the voltage level of the current detection signal is set in advance. By setting the voltage level higher than the voltage level of the voltage detection signal, the signal from the output current detection circuit 38 is prioritized and the control power supply device performs the constant current control, and then the resistance value of the halogen lamp LMP changes to the temperature. Since the current value decreases as it rises and stabilizes, the value output from the output voltage detection circuit 37 becomes larger than the value output from the output current detection circuit 38.
As shown in, the duty is regulated in the PWM control circuit 36, and the control shifts to the constant voltage control. In this way, the inrush current to the lamp LMP is limited by the constant current control, the stable control of the luminous flux is performed by the constant voltage control, and the input line current is changed from the peak shape of (a) of FIG. 7 to (b). The sine-wave control is performed.

The above-mentioned two control operations are performed while being switched every clock output from the clock 41 as shown in FIG. The analog switch 42 alternately switches the signal input to the PWM control circuit 36 between the input stage side and the output stage side for each pulse output from the clock 41, and latches the drive signals of the transistors Ts and T1 at that time. It is held by the circuits 43 and 44 to determine ON / OFF of the no-signal period. At this time, the oscillation frequency of the clock 41 is set sufficiently higher than the switching frequencies of the switching elements Ts and T1.

As described above, according to this embodiment,
In a circuit that supplies power to a lamp load that increases the inrush current, a so-called light amount control circuit, etc., it is possible to shorten the rise time while limiting the inrush current when the lamp is lit, and to reduce the stress on the switching element. Can be reduced. In addition, the power factor on the commercial power supply side and the current waveform distortion can be reduced during lighting, and the ripple current of the smoothing capacitor can be significantly reduced, improving the reliability of the power supply and reducing the stress on the switching element. Also, the filter at the input stage can be reduced.

In this embodiment, the case where a transistor is used as a switching element has been described, but any switching element such as FET or IGBT can be used as long as high speed switching is possible, and current detection is performed by a resistor. Alternatively, a current transformer or the like may be used.

(Sixth Embodiment) A sixth embodiment shown in FIG. 9 has a circuit configuration substantially the same as that of the fifth embodiment. The input stage is a step-up / down type, and a DC voltage detecting circuit 50 is provided at its DC output section. The only difference is that the feedback of the load current is eliminated.

That is, by sending the output of the DC voltage detection circuit 50 to the multiplication circuit 33, the peak value of the input current is varied so that the DC output voltage fluctuation of the input stage due to the input voltage fluctuation and the sudden load change does not occur, and the DC output Performs constant current / constant voltage control. Other operations are the same as those in the fifth embodiment.

(Embodiment 7) Embodiment 7 will be described. Figure 10
In the seventh embodiment shown in FIG. 11, the circuit configuration is almost the same as that of the fifth embodiment, and the current detection level in the output current detection circuit 38 is
A portion where the multiplier of the multiplication circuit that determines the input current peak value is used as an offset signal given from the CPU 7 on the device body side,
Also, the only difference is the addition of the light flux reading section of the lamp.

With this configuration, the detection level is controlled by the CPU 7 so that the time until the luminous flux of the lamp is stabilized and the current detection level are mutually optimal, and the DC output control of the input stage is controlled by the load. It is possible to change it when it fluctuates (load on / off, etc.).

It is more optimal to use fuzzy control, neuro control, etc., which have come to be used in many home electric appliances, in the detection level control in addition to the luminous flux and the parameters such as the heat generation amount of the switching element. Various controls are possible.

(Embodiment 8) An embodiment 8 will be described. The present embodiment is an example in which the control power supply device of the fifth embodiment is used as a control circuit for a load having a low average current with respect to a peak current such as a motor load. If this control power supply device is applied to the motor load control circuit, it works as a constant current control circuit when the peak current becomes large to suppress the peak current and reduce the stress on the switching element. It becomes possible to design the heat sink, transformer, and switching element with the average current, which had to be done.

[0047]

As described above, according to the present invention,
When connecting a load such as a lamp or motor that flows a large inrush current when the power is turned on, the inrush current can be suppressed.
Moreover, the load current can be stabilized in a short time. In addition, claim 4
In the inventions of to 7, it is possible to further control the AC input current in a sinusoidal shape, improve the power factor, and reduce the current waveform distortion.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a first embodiment.

FIG. 2 is an operation explanatory diagram of the first embodiment.

FIG. 3 is a circuit diagram of a second embodiment.

FIG. 4 is a circuit diagram of a third embodiment.

FIG. 5 is a circuit diagram of a fifth embodiment.

FIG. 6 is an operation explanatory diagram of the fifth embodiment.

FIG. 7 is a waveform chart of each part of Example 5.

FIG. 8 is an explanatory diagram of time division control in the fifth embodiment.

FIG. 9 is a circuit diagram of a sixth embodiment.

FIG. 10 is a circuit diagram of Example 7.

FIG. 11 is an explanatory diagram of a phase control method.

FIG. 12 is an explanatory diagram of soft start.

FIG. 13 is a circuit diagram of a conventional example.

[Explanation of symbols]

 1 Output voltage detection circuit 2 Output current detection circuit 3 PWM control circuit 4 OR circuit

Claims (7)

[Claims] 1. An output current detecting means, an output voltage detecting means, a selecting means for selecting an output having a larger value from the output of the output current detecting means and the output of the output voltage detecting means, and the control power supply device. 2. A control power supply device, comprising: a switching element that connects and disconnects the main circuit of 1. and a control unit that controls the switching element to be connected and disconnected according to the output of the selection unit. 2. The control power supply device according to claim 1, further comprising an input voltage detection means and a correction means for correcting the output of the output current detection means by the output of the input voltage detection means. 3. A light flux detecting means for detecting a light flux of a lamp which is a load, and a detection level setting means for setting a detection level of the output current detecting means according to an output of the light flux detecting means. The control power supply device according to claim 1. 4. A control power supply device comprising an input stage and an output stage, the input stage comprising a rectifier circuit, an AC input voltage waveform detecting means for detecting a waveform of an AC input voltage of the rectifier circuit, and the input. A first switching element for connecting and disconnecting the main circuit of the stage, a first output current detecting means for detecting an output current of the input stage, and an output waveform of the first output current detecting means for detecting the AC input voltage waveform. A first switching element for intermittently controlling the first switching element so as to approximate the output waveform of the first means;
And a second output current detecting means for detecting an output current of the output stage, an output voltage detecting means for detecting an output voltage of the output stage, and a second output current. Selecting means for selecting a larger value output from the detecting means and the output of the output voltage detecting means; a second switching element for connecting and disconnecting the main circuit of the output stage; and the second switching element according to the output of the selecting means. And a second control means for intermittently controlling the second switching element. 5. The control power supply device according to claim 4, wherein one control means is switched in a time division manner to serve as the first control means and the second control means. 6. A second output voltage detecting means for detecting the output voltage of the input stage is further provided, and the first control means is operated so that the output level of the second output voltage detecting means becomes constant. The control power supply device according to claim 4, which is characterized in that. 7. A light flux detecting means for detecting a light flux of a lamp, which is a load, and a detection level setting means for setting a detection level of the second output current detecting means according to an output of the light flux detecting means. The control power supply device according to claim 4, wherein: