JPH1066334A - System for controlling stabilization of output voltage - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize the output voltage of a switching power source so that no overvoltage can be applied across an element which is connected to the power source as a load by detecting in advance the abrupt reduction of the load current of the power source and utilizing the detected signal of the abrupt reduction for controlling the width of a switching pulse. SOLUTION: A logic controller 4 judges the operating state of a load 3 in accordance with a logic control program and, when the controller 4 detects the abrupt reduction of the current consumption of the load 3 in advance, a power source control section 11 drops the reference voltage of a reference voltage input circuit 11c which is the input of an operational amplifier 11b for controlling voltage, and then, reduces the width of the output pulse of a comparator 11a for generating switching pulse. Therefore, the output voltage (g) of a switching power source 1 is dropped by outputting the output pulse of the comparator 11a to the switching transistor 10a of the DC-DC converting section 10 of the power source 1 and, thereafter, the current consumption of the load 3 is abruptly reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an output voltage stabilization control method for a switching power supply.

[0002]

2. Description of the Related Art Conventionally, output voltage stabilization control in a switching power supply has been disclosed in the publication "Switching Power Supply Technology" (author: Tamotsu Ninomiya) published on June 30, 1988.
As shown on pages 16 to 16, the output voltage of the switching power supply is compared with a reference voltage, and the switching pulse width is controlled according to the difference.

FIG. 6 is a block diagram showing a conventional technique, and comprises a switching power supply 1A having a DC-DC converter 10 and a power supply controller 12, a load cable 2, and a load 3. Further, the power supply control unit 12 has a DC-DC
The switching unit 10 includes a switching pulse generation comparator 12a that outputs a switching pulse f to the switching transistor 10a of the conversion unit 10, and a voltage control operational amplifier 12b. The output d of the voltage control operational amplifier 12b and the comparator input triangular wave e are input to the switching pulse generation comparator 12a, and the reference voltage of the reference voltage input circuit 12c and the output voltage sense circuit are input to the voltage control operational amplifier 12b. The output voltage of 12d is input.

The output voltage g of the DC-DC converter 10 is input to a voltage control operational amplifier 12b as an output voltage of an output voltage sensing circuit 12d, and is compared with a reference voltage of a reference voltage input circuit 12c. The result of the comparison is input to the switching pulse generating comparator 12a as an output d. The comparator 12a for generating a switching pulse
The width of the switching pulse f is adjusted based on the output d from the voltage control operational amplifier 12b and the comparator input triangular wave e. The adjusted switching pulse f is output from the switching pulse generation comparator 12a to the switching transistor 10a of the DC-DC converter 10,
Complete control.

[0005]

A problem with the above-mentioned prior art is that no measure is taken when the current consumption of the load is sharply reduced. That is, when a steep current fluctuation di / dt of the load occurs, a voltage of L · di / dt occurs due to the internal inductance L of the load cable for transmitting the current from the switching power supply to the load,
There is a problem that the output voltage rises transiently and an overvoltage is applied to a load element.

SUMMARY OF THE INVENTION An object of the present invention is to realize an output voltage stabilization control method in which an overvoltage is not applied to a load element even when the current consumption of a load sharply decreases.

[0007]

According to a first output voltage stabilization control method of the present invention, a steep decrease in load current of a switching power supply is detected in advance, and a detection signal is used for controlling a switching pulse width. It is characterized by.

According to a second output voltage stabilization control method of the present invention, the output voltage of a switching power supply is compared with a reference voltage, and the difference is input to switching pulse generation means to control the width of the switching pulse. An output voltage stabilization control method in a switching power supply, comprising a logic control program for controlling the operation of a load, detecting a sharp decrease in load current from the logic control program, and outputting a reference voltage input circuit of the switching power supply. A logic control device for transmitting a load current decrease signal to the switching power supply, and a power supply control unit of the switching power supply for reducing a reference voltage by the load current reduction signal to reduce a width of a switching pulse, and a steep decrease in load current. Prior to this, the output voltage of the switching power supply is reduced by a certain value.

A third output voltage stabilization control method according to the present invention is the second output voltage stabilization control method according to the second invention,
The load current decrease signal is input to an output voltage sensing circuit of the switching power supply, and changes the output voltage to lower the output voltage of the switching power supply by a certain value.

A fourth output voltage stabilization control method according to the present invention is the same as the second output voltage stabilization control method according to the invention,
The load current decrease signal is input to both a reference voltage input circuit and an output voltage sense circuit of the switching power supply, and by changing the reference voltage and the output voltage,
The output voltage of the switching power supply is reduced by a certain value.

A fifth output voltage stabilization control method according to the present invention is the second output voltage stabilization control method according to the second invention,
The load current decrease signal is input to a switching pulse generation unit of the switching power supply, and reduces the output voltage of the switching power supply by a certain value.

According to a sixth output voltage stabilization control method of the present invention, in the second to fifth output voltage stabilization control methods of the present invention, the constant value can be arbitrarily set from a plurality of types. And

According to a seventh output voltage stabilization control method of the present invention, in the second to fifth output voltage stabilization control methods of the present invention, the output voltage of the switching power supply is changed to a specific value instead of decreasing by a fixed value. It is characterized in that it can be set to a voltage.

An eighth output voltage stabilization control method according to the present invention is the same as the seventh output voltage stabilization control method according to the invention,
The specific voltage can be arbitrarily set from a plurality of types.

[0015]

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

FIG. 1 is a block diagram showing a first embodiment of the present invention.

The switching power supply 1 is connected to a load 3 by a load cable 2 having an internal inductance. The configuration of the switching power supply 1 is almost the same as that of FIG. 6 described in the related art, except that the power supply control unit 11 adds the load current decrease signal b. The logic control device 4 which is a feature of the present invention controls the power supply control unit 11 of the switching power supply 1 and the load 3 and includes a logic control program for the load 3.

FIG. 2 is a time chart showing a signal flow according to the first embodiment of the present invention, FIG. 3 is a block diagram showing a second embodiment of the present invention, and FIG. FIG. 5 is a block diagram showing a third embodiment of the present invention, and FIG. 5 is a block diagram showing a fourth embodiment of the present invention.

Next, the operation of the first embodiment of the present invention will be described in detail with reference to FIGS.

The logic control device 4 determines the operating condition of the load 3 according to the logic control program, and when it detects in advance that the current consumption of the load 3 is sharply reduced, the logic control device 4 The load current decrease signal b shown in FIG. 2 is transmitted. As a result, the power supply controller 11 lowers the reference voltage of the reference voltage input circuit 11c, which is the input of the voltage control operational amplifier 11b, as shown in FIG. At this time, the voltage to be dropped is set to a constant value in advance, but can be set from a plurality of types.

The output d of the voltage control operational amplifier 11b is
Due to the drop in the reference voltage, the voltage changes as shown in FIG. 2D, and the output pulse width of the switching pulse generating comparator 11a is reduced as in the switching pulse f in FIG. This switching pulse f is generated by the switching power supply 1
Switching transistor 1 of DC-DC converter 10
0a to reduce the output voltage g of the switching power supply 1.

The above operation is performed prior to a sharp decrease in the current consumption of the load 3 by the logic control program of the logic control device 4. That is, the logic control device 4 sends the load current decrease signal b to the power supply control unit 11 of the switching power supply 1 a time before the time required for the above-described operation from the time of the steep decrease in the current consumption of the load 3, and then performs the above-described operation. After the elapse of the time required for, the load 3 is instructed to sharply reduce the current consumption.

After this, when the load current increases,
The logic controller 4 controls the power supply controller 11 of the load current decrease signal b.
Stop sending to.

Next, the operation of the second embodiment of the present invention will be described with reference to FIG.

In the first embodiment of the present invention, the load current decrease signal b lowers the reference voltage of the reference voltage input circuit 11c which is the input of the voltage control operational amplifier 11b. In the second embodiment, a voltage control operational amplifier 11 is used instead of the reference voltage as shown in FIG.
The difference is that the output voltage of the output voltage sensing circuit 11d, which is the other input of b, is changed.

Next, the operation of the third embodiment of the present invention will be described with reference to FIG.

In the first or second embodiment of the present invention, the reference voltage of the reference voltage input circuit 11c or the output voltage of the output voltage sense circuit 11d is changed by the load current decrease signal b. The third embodiment differs from the third embodiment in that both the reference voltage of the reference voltage input circuit 11c and the output voltage of the output voltage sense circuit 11d are changed as shown in FIG.

Next, the operation of the fourth embodiment of the present invention will be described with reference to FIG.

The fourth embodiment of the present invention is characterized in that the output d of the voltage control operational amplifier 11b is changed by the load current decrease signal b as shown in FIG.
This embodiment is different from the embodiment.

In this embodiment, DC-D
Although described as the switching power supply 1 including the C conversion unit 10, a switching power supply including an AC-DC conversion unit may be used.

[0031]

As described above, the effect of the present invention is that even if the current consumption of the load is sharply reduced, the output voltage is reduced before the output voltage transiently increases.
An output voltage stabilization control method in which an overvoltage is not applied to a load element can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 2 is a time chart showing a signal flow according to the first embodiment of the present invention.

FIG. 3 is a block diagram showing a second embodiment of the present invention.

FIG. 4 is a block diagram showing a third embodiment of the present invention.

FIG. 5 is a block diagram showing a fourth embodiment of the present invention.

FIG. 6 is a block diagram showing a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Switching power supply 2 Load cable 3 Load 4 Logic control device 10 DC-DC conversion part 10a Switching transistor 11 Power supply control part 11a Switching pulse generation comparator 11b Voltage control operational amplifier 11c Reference voltage input circuit 11d Output voltage sense circuit

Claims (8)

[Claims] 1. An output voltage stabilization control method, wherein a steep decrease in load current of a switching power supply is detected in advance, and a detection signal is used for controlling a switching pulse width. 2. An output voltage stabilization control method for a switching power supply, comprising: comparing an output voltage of a switching power supply with a reference voltage; and inputting the difference to a switching pulse generating means to control a width of the switching pulse. A logic control device comprising a logic control program for controlling the operation of the load, detecting a sharp decrease in load current from the logic control program, and sending a load current decrease signal to a reference voltage input circuit of the switching power supply; A power supply control unit of the switching power supply for reducing a reference voltage by the load current decrease signal to reduce a width of a switching pulse, and the output voltage of the switching power supply is fixed to a certain value before the load current sharply decreases. An output voltage stabilization control method characterized by decreasing the value. 3. The switching power supply according to claim 1, wherein the load current decrease signal is input to an output voltage sensing circuit of the switching power supply, and the output voltage is changed to lower the output voltage of the switching power supply by a certain value. Item 2. An output voltage stabilization control method according to Item 2. 4. The load current decrease signal is input to both a reference voltage input circuit and an output voltage sense circuit of the switching power supply, and changes the reference voltage and the output voltage to change the output voltage of the switching power supply. 3. The output voltage stabilization control method according to claim 2, wherein the output voltage stabilization control value is reduced by a predetermined value. 5. The output voltage stabilization according to claim 2, wherein the load current decrease signal is input to a switching pulse generating means of the switching power supply, and lowers an output voltage of the switching power supply by a certain value. control method. 6. The method according to claim 2, wherein the predetermined value can be set arbitrarily from a plurality of types.
Output voltage stabilization control method described in section. 7. The output voltage stabilization control method according to claim 2, wherein the output voltage of the switching power supply can be set to a specific voltage instead of decreasing by a fixed value. 8. The output voltage stabilization control method according to claim 7, wherein the specific voltage can be arbitrarily set from a plurality of types.