JPH07303330A - Power supply - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a power supply device capable of supplying a stable power supply to a load by sensing the output power due to the changing current and voltage of the power supply input terminal and correcting the output voltage input to the load. To do. An input voltage sensing means 10 for sensing a changing voltage at an AC power source input terminal, an input current sensing means 20 for sensing a varying current at an AC power source input terminal, and sensed input voltage data and input current data Control means 30 for receiving and calculating the changing output power of the AC power supply input terminal to control the operation, buffer means 40 for receiving the control signal from the control means and driving the output terminal, and voltage signal from the buffer means. D / A conversion means 50 for converting digital data to analog, reference voltage generation means 60 for receiving the converted analog voltage data and generating a reference voltage so as to supply a stable power supply to the load, and reference voltage generation means. The reference voltage signal of the reference voltage generating means and the triangular wave signal from the triangular wave generating means 75 are compared so that the power supply means is driven by the reference voltage from And a comparison means 70.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device controlled by a switching system, and more particularly to a power supply device equipped with a D / A converter capable of supplying a stable power supply regardless of changes in load and power supply voltage. Regarding

[0002]

2. Description of the Related Art Generally, in a power supply device controlled by a conventional switching method, an output voltage supplied to a load is corrected by comparing a current change amount at a power supply input end with a reference voltage to output an output by the load. The deviation was minimized. That is, the output voltage is corrected by shutting off the power supplied to the load when the load is over, and driving the load until the reference voltage rises during normal operation.

[0003]

However, in such a conventional method, since the output voltage is adjusted by sensing only the changing input current at the power input terminal, the configuration for detecting the input current is provided. When the output error of the device causes an output deviation of several 100 W and the input voltage supplied from the power supply input terminal fluctuates greatly, it cannot be controlled, and therefore a stable power supply is supplied to the load. There was a problem that I could not.

Further, when the power supply device is used for an electric heating device such as a cooker, an output error due to an output error of a constituent element occurs within a range of 20%, so a fire occurs in an area where a high voltage line or the like passes. May occur, and in a low voltage area, normal output may not be supplied,
Therefore, there is a problem in that a stable cooking state cannot be expected and consumer confidence in the product cannot be obtained.

Therefore, the present invention has been made to solve the above-mentioned problems in the prior art, and an object of the present invention is to detect an output voltage due to a changing current and a voltage at a power input terminal and to detect a load. D / A that can supply a stable power supply to the load by correcting the output voltage input to the
It is to provide a power supply device including a converter.

Another object of the present invention is to provide a power supply device equipped with a D / A converter that displays an error when an abnormality occurs and shuts off the power supply to the load.

[0007]

In order to achieve the above object, a power supply device according to the present invention comprises an input voltage sensing means for sensing a changing input voltage of an AC power input terminal, and a change of the AC power input terminal. Input current sensing means for sensing an input current, and input power data sensed by the input voltage sensing means and input current data sensed by the input current sensing means to change the output power of the AC power input terminal. To control the overall operation, buffer means for receiving the control signal from the control means to drive the output terminal, and digital data of the voltage signal output from the buffer means to analog D / A converting means for receiving the analog voltage data converted by the D / A converting means and supplying a stable power source to the load. Reference voltage generating means for generating a reference voltage and comparing means for comparing the reference voltage signal of the reference voltage generating means and the triangular wave signal of the triangular wave generating means so as to drive the power supply means with the reference voltage from the reference voltage generating means. It consists of and.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

As shown in FIGS. 1 and 2, the input voltage sensing means 10 senses a changing input voltage of the commercial AC power source supplied from the AC power source input terminal 1, and the input voltage sensing means 10 is provided. Is a pressure reducing transformer 11 for applying a commercial AC power source supplied from the AC power source input terminal 1 to the primary side to reduce the voltage to a predetermined low voltage and induce the secondary side, and an AC voltage reduced by the pressure reducing transformer 11. And a smoothing capacitor C1 connected to the output end of the bridge rectifier 12 for filtering the ripple component contained in the DC voltage full-wave rectified by the bridge rectifier 12. , Voltage dividing resistors R1 and R2 that divide the DC voltage filtered by the smoothing capacitor C1 into a predetermined ratio, and voltage dividing resistors R1 and R
In order to filter the noise component contained in the voltage signal divided by 2, the voltage dividing resistors R1 and R2 are connected in series with the capacitor C2.

The input current sensing means 20 senses the varying input current of the commercial AC power source supplied from the AC power source input terminal 1 and the variation amount of the current inputted to the load 81. The means 20 converts a changing input current of the AC power supply input terminal 1 and a current change amount input to the load 81, and converts the current change amount sensed by the current transformer 21 into a voltage. Current transformer 21
R2 connected in parallel to the secondary side of the capacitor, a capacitor C3 connected in parallel to the resistor R3 for filtering a noise component included in the voltage signal converted into a voltage by the resistor R3, and a filtering by the capacitor C3. The bridge rectifier 22 receives the generated voltage signal and performs full-wave rectification on the direct current, and is connected to the output terminal of the bridge rectifier 22 for filtering the ripple component included in the direct-current voltage full-wave rectified by the bridge rectifier 22. Smoothing capacitor C4, resistors R4 and R5 for adjusting the voltage ratio for receiving the DC voltage filtered by the smoothing capacitor C4 and setting the feedback voltage of the power supply means 80, and the variable resistor VR1, and the resistor R4.
A Zener diode ZD1 that receives a voltage signal whose voltage ratio is adjusted by R5 and a variable resistor VR1 and bypasses only a predetermined breakdown voltage abnormality, and a ripple component included in the DC voltage that is full-wave rectified by the bridge rectifier 22. The capacitor C5 filters the noise component input to the control means described later and prevents the post-operation of the control means.

Further, the control means 30 is the input voltage sensing means 1
0 is a microcomputer that receives the input voltage data sensed by 0 and the input current data sensed by the input current sensing means 20, and controls the overall operation of the power supply device. Means 1
While receiving the changing input voltage data of the AC power source input terminal 1 sensed by 0 through the input terminal A / D1,
The changing input current data of the AC power supply input terminal 1 sensed by the input current sensing means 20 is received via the input terminal A / D2, and the input voltage data is multiplied by the input current data to change the AC power supply input terminal 1. Calculate the output voltage.

The buffer means 40 is also a control means 30.
The buffer means 40 receives the voltage data of the control signal output from the
An amplifier 41 for amplifying the voltage data output from the output terminal P1 of the control means 30, and a ground terminal of the control means 30 and the power supply means 80 so that the voltage data amplified by the amplifier 41 is supplied to the output terminal. And a photocoupler 42 for separating the.

Further, in the drawing, D / A conversion means 50
Converts the digital data of the voltage signal output from the buffer unit 40 into an analog signal and outputs it so that the drive duty of the power supply unit 80 can be varied.

Further, the reference voltage generating means 60 receives the voltage data converted into an analog signal by the D / A converting means 50 and generates a reference voltage for supplying a stable power source to the load 81. The reference voltage generation means 60 has an operational amplifier 61 that amplifies the analog voltage data converted by the D / A conversion means 50, and the voltage signal amplified by the operational amplifier 61 regardless of the fluctuation of the load 81. Buffer amplifier 62 for safely supplying to the output terminal
A resistor R7 and a capacitor C6 for filtering a noise component contained in the voltage signal from the buffer amplifier 62; and a Zener for receiving a voltage signal filtered by the resistor R7 and the capacitor C6 and bypassing only a predetermined breakdown voltage abnormality. It is composed of a diode ZD2 and a diode D1 which limits the maximum value of the breakdown voltage bypassed by the Zener diode ZD2.

Further, the comparing means 70 receives the reference voltage signal from the reference voltage generating means 60 at the non-inverting terminal (+) and the triangular wave signal from the triangular wave generating means 75 at the inverting terminal (-), Is a comparator for comparing.

Further, the power supply means 80 is a comparison means 7.
It is a switching type power supply device (SMPS) that receives a comparison signal whose amplitude and frequency are modulated by 0 and supplies a stable power source to the load 81 by the switching system.

The operation of the power supply device of the present invention constructed as above will be described below. First, when power is supplied to the power supply device, the input voltage of the commercial AC power supplied from the AC power input terminal 1 is reduced to a predetermined low voltage by the pressure reducing transformer 11 of the input voltage sensing means 10, and the pressure reducing transformer 11 is supplied. The AC voltage reduced by is full-wave rectified by the bridge rectifier 12 into a DC voltage. The ripple component contained in the DC voltage full-wave rectified by the bridge rectifier 12 is filtered by the smoothing capacitor C1, and the DC voltage filtered by the smoothing capacitor C1 is divided into a predetermined ratio through the voltage dividing resistors R1 and R2. It is then input to the input terminal A / D1 of the control means 30.

The input current sensing means 20 detects the changing input current of the commercial AC power source supplied from the AC power source input terminal 1.
Of the current transformer 21, and the sensed input current is converted into a voltage proportional to the amount of change in current through a resistor R3, and a noise component included in the converted voltage signal is filtered through a capacitor C3. To be done. Thereafter, the voltage signal whose noise component is filtered by the capacitor C3 is full-wave rectified by the bridge rectifier 22 into a DC voltage, and the ripple component included in the full-wave rectified DC voltage is filtered by the smoothing capacitor C4. . The DC voltage from the bridge rectifier 22 filtered by the smoothing capacitor C4 is adjusted at a predetermined voltage ratio through the resistors R4 and R5 and the variable resistor VR1 and input to the input terminal A / D2 of the control means 30. On this occasion,
The voltage signal adjusted to a predetermined voltage ratio by the resistors R4 and R5 and the variable resistor VR1 is a Zener diode ZD.
Only the predetermined breakdown voltage abnormality is bypassed through 1.

In the control means 30, the input voltage sensing means 10
The changing current of the AC power supply input end 1 is multiplied by the changing input voltage data of the AC power supply input end 1 detected by the input current sensing device 20 and the changing input current data of the AC power supply input end 1 detected by the input current sensing means 20. Calculate the output power. Then, the control means 30 compares the calculated output voltage of the AC power supply input terminal 1 with preset reference output data. As a result of the comparison, when the output power of the AC power supply input terminal 1 calculated by the control means 30 is smaller than the reference output data, the output port value is set to 1B so as to increase the reference voltage.
The control signal raised by it is output to the buffer means 40. On the other hand, the AC power supply input terminal 1 calculated by the control means 30
When the changing output power of is larger than the reference output data, the control signal with the output port value lowered by 1 bit so as to lower the reference voltage is output to the buffer means 40.

The amplification section 41 of the buffer means 40 amplifies the voltage data of the control signal from the control means 30 and outputs it to the photocoupler 42. The photocoupler 42 controls the control means 30 to prevent malfunction of the control means 30. The ground terminal of the power supply unit 80 is separated, and the voltage data amplified by the amplification unit 41 is supplied to the D / A conversion unit 50.

The D / A conversion means 50 is a power supply means 80.
The digital data of the voltage signal from the buffer means 40 is converted into analog so as to change the drive duty of, and output to the reference voltage generation means 60.

The reference voltage generating means 60 amplifies the analog voltage data converted by the D / A converting means 50 through the operational amplifier 61, and the amplified voltage data is a buffer amplifier regardless of the fluctuation of the load 81. It is supplied to the non-inverting terminal (+) of the comparing means 70 through 62.

In the comparison means 70, the reference voltage generation means 60
The non-inverted terminal (+) receives the reference voltage signal from, and the inversion terminal (-) receives the triangular wave signal from the triangular wave generating means 75 to compare them. As a result of the above comparison, when the reference voltage signal from the reference voltage generating means 60 is smaller than the triangular wave signal, the driving of the power supply means 80 is cut off and the power supplied to the load 81 is cut off, while the reference voltage is decreased. When the reference voltage signal from the generating means 60 is larger than the triangular wave signal, the power supply means 80 is driven to supply power to the load 81.

At this time, the current transformer 2 of the input current sensing means 20.
In No. 1, the amount of change in current input to the load 81 is sensed and output to the control means 30. Therefore, the control means 30 periodically generates the analog voltage data through the D / A conversion means 50 to determine the abnormal state of the load 81 (for example, when the container is not placed on the cooker). When an abnormality occurs, the drive of the power supply means 80 is shut off while displaying an error through a display means (not shown). As a result, the power supplied to the load 81 is shut off and the equipment can be protected.

[0025]

As described above, according to the power supply device of the present invention, the load is corrected by detecting the output power due to the changing current and voltage at the power input terminal and correcting the output voltage input to the load. A stable power supply can be supplied.
Further, when an abnormality occurs, the power supplied to the load is shut off while displaying an error, so that the product can be protected and the reliability of the consumer with respect to the product can be improved.

[Brief description of drawings]

FIG. 1 is a control block diagram of a power supply device according to an exemplary embodiment of the present invention.

FIG. 2 is a detailed circuit diagram of a power supply device according to an exemplary embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 AC power supply input terminal 10 Input voltage sensing means 11 Pressure reducing transformer 12 Bridge rectifier 20 Input current sensing means 21 Current transformer 22 Bridge rectifier 30 Control means 40 Buffer means 41 Amplification section 42 Photocoupler 50 D / A conversion means 60 Reference voltage generation means 61 operational amplifier 62 buffer amplifier 70 comparing means 75 triangular wave generating means 80 power supply means 81 load

Claims (5)

[Claims] 1. An input voltage sensing means for sensing a changing input voltage of an AC power source input terminal, an input current sensing means for sensing a varying input current of the AC power source input terminal, and an input voltage sensing means. Receiving the input voltage data and the input current data sensed by the input current sensing means, calculating the changing output power of the AC power supply input terminal and controlling the overall operation, and the control means from the controlling means. Buffer means for receiving the control signal and driving the output end, D / A conversion means for converting the digital data of the voltage signal output from the buffer means into analog, and analog conversion converted by the D / A conversion means Reference voltage generating means for receiving a voltage data and generating a reference voltage so as to supply a stable power source to the load; and a reference from the reference voltage generating means. A power supply device comprising a comparison means for comparing the reference voltage signal of the reference voltage generation means and the triangular wave signal of the triangular wave generation means so as to drive the power supply means by a voltage. 2. The input voltage sensing means includes a decompression transformer for decompressing a commercial AC power source supplied from the AC power source input terminal to a predetermined low voltage, and an AC voltage decompressed by the decompression transformer into a DC full wave. A bridge rectifier for rectifying,
A smoothing capacitor for filtering the ripple component included in the DC voltage full-wave rectified by the bridge rectifier, a voltage dividing resistor for dividing the DC voltage filtered by the smoothing capacitor at a predetermined ratio, and the voltage dividing unit. 2. The power supply device according to claim 1, wherein the power supply device comprises a capacitor for filtering a noise component included in the voltage signal divided by the resistor. 3. The input current sensing means includes a current transformer that senses a varying input current at the input end of the AC power source and a current variation amount of a load, and a current variation amount sensed by the current transformer as a voltage. A third resistor for converting, a capacitor for filtering a noise component contained in the voltage signal converted by the third resistor, a bridge rectifier for full-wave rectifying the voltage signal filtered by the capacitor into direct current, A smoothing capacitor for filtering the ripple component included in the DC voltage full-wave rectified by the bridge rectifier, and a voltage for receiving the DC voltage filtered by the smoothing capacitor and setting the feedback voltage of the power supply means. The fourth and fifth resistors and the variable resistor that adjust the ratio, and the fourth and fifth resistors and the variable resistor A Zener diode which receives an adjusted voltage signal and bypasses only a predetermined breakdown voltage abnormality, and a ripple component included in the DC voltage that is full-wave rectified by the bridge rectifier are filtered and input to the control means. The power supply device according to claim 1, wherein the power supply device comprises a capacitor that filters a noise component that is generated. 4. The amplification means for amplifying the voltage data output from the control means, and the buffer means grounding the control means and the power supply means so as to supply the voltage data amplified by the amplification to an output end. 2. A photocoupler for separating the ends.
The power supply device described. 5. The reference voltage generating means has an operational amplifier that amplifies the analog voltage data converted by the D / A converting means, and the voltage signal amplified by the operational amplifier is independent of load fluctuations. To the output terminal, a resistor and a capacitor for filtering a noise component included in the voltage signal from the buffer amplifier, and a predetermined breakdown voltage abnormality by receiving the voltage signal filtered by the resistor and the capacitor. The power supply device according to claim 1, wherein the power supply device comprises a zener diode that bypasses only the zener diode and a diode that limits the maximum value of the breakdown voltage bypassed by the zener diode.