JPH0592821U - Continuous control DC stabilized power supply circuit - Google Patents

Abstract

(57) [Summary] [Object] To provide a continuous control type DC stabilized power supply circuit capable of obtaining an output voltage without overshoot and undershoot even when switching a preset voltage. [Configuration] Voltage dividing circuit 7 _{1 that} divides the voltage of the reference voltage source 4
To 7 _3, the preset switch 10 for designating an analog switch circuit 8 for selecting one of the divided output of the voltage divider circuit ₇₁ to 7 _3, one in the output of the voltage divider circuit 7 ₁ to 7 ₃ And an encoder 11 that receives the output of the preset switch 10 as an input and controls the analog switch circuit 8 by the output to select the output of the voltage dividing circuit designated by the preset switch 10 and is selected by the analog switch circuit 8. The output voltage or output current is controlled based on the preset voltage based on the divided output voltage.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a continuous control type stabilized DC power supply circuit in which the output voltage is switchable.

[0002]

[Prior Art]

A conventional continuous control type DC stabilized power supply circuit having a switchable output voltage has a basic configuration shown in FIG. That is, the output voltage control transistor 1 connected in series to the load, the reference voltage source 4A, the resistor 2 for dividing the voltage Vref of the reference voltage source 4A, and the selection switch 6 are selectively connected in series to the resistor 2. The voltage dividing circuit 30 including the resistors 31, 32 or 33 and the difference between the divided voltage output voltage of the voltage dividing circuit 30 and the output voltage E ₀ are detected and V _CE of the transistor 1 is controlled based on the detected difference. And a differential amplifier 5.

If the resistance value of the resistor 2 is Rs and the resistance value of the resistor selected by the selection switch 6 is Rf, the output voltage E ₀ of the above-described conventional continuous control type DC stabilized power supply circuit is E It is set by ₀ = Rf · Vref / (Rf + Rs). Generally, as shown in FIG. 3, the resistance value Rf is made variable by selecting one of the resistors 31, 32, or 33 by the selection switch 6, or the reference voltage Vref is made variable, and the output The constant voltage of the voltage E ₀ is set.

Therefore, when the output voltage E ₀ is switched to a preset value and used, the preset output voltage value is changed by changing the resistance value Rf by switching the resistors 31, 32 and 33 by the selection switch 6. Can be set.

[0005]

[Problems to be solved by the device]

However, in the above-mentioned conventional continuous control type DC stabilized power supply circuit, when the output voltage E ₀ is switched to the preset output voltage value by switching the resistance value Rf, a BBM type switch is used as the selection switch 6. At this time, as shown in FIG. 4 (a), there is a problem that the maximum output voltage is momentarily output at the time of switching and then set to a preset value. Further, when an MBB type switch is used as the selection switch 6, there is a problem that an undershoot voltage is momentarily output to the output at the time of switching and then set to a preset value as shown in FIG. 4B. It was

On the other hand, when the switching method of the reference voltage Vref is adopted, there is a problem that a circuit capable of arbitrarily setting a staircase wave voltage without overshoot or undershoot is required, which is expensive.

An object of the present invention is to provide a continuous control type DC regulated power supply circuit which has a simple configuration and can obtain an output voltage without overshoot and undershoot even when switching a preset voltage. ..

[0008]

[Means for Solving the Problems]

 The continuous control type DC stabilized power supply circuit of the present invention is a continuous control type DC stabilized power supply circuit capable of presetting an output voltage or output current, and includes a plurality of voltage dividing circuits for dividing a reference voltage and the plurality of voltage dividing circuits. An analog switch circuit that selects one of the voltage-divided outputs from the voltage circuit, a designating unit that designates one of the outputs of the plurality of voltage-dividing circuits, and an analog output based on the output of the designating unit. An encoder that controls the switch circuit to select the output of the voltage dividing circuit specified by the specifying means, and controls the output voltage or output current based on the preset voltage based on the divided output voltage selected by the analog switch circuit It is characterized by doing.

[0009]

[Action]

 According to the continuous control type DC stabilized power supply circuit of the present invention, the preset voltage based on the selected divided voltage is selected by the encoder and the analog switch circuit in cooperation with the divided output voltage specified by the specifying means. The output voltage or output current is controlled based on In this case, the encoder output does not become indeterminate when the selected divided voltage is switched by the specifying means, and the analog switch circuit causes overshoot or undershoot in the divided output voltage when switching the selection. There is no slippage. Therefore, the preset voltage does not overshoot or undershoot.

[0010]

【Example】

 Hereinafter, the present invention will be described with reference to examples. FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

In one embodiment of the present invention, the same components as those of the conventional example shown in FIG. 3 are designated by the same reference numerals and the description thereof will be omitted to avoid duplication. A is the main circuit of the continuous control DC stabilized power supply, and B is the output voltage preset circuit built into the continuous control DC stabilized power supply circuit.

The output voltage preset circuit section B is a potentiometer 7 ₁ , 7 ₂ that constitutes a preset potentiometer 7 that divides the voltage of the reference voltage source 4 in the main circuit section A of the DC power source for continuous control system separately. , 7 ₃ , an analog switch circuit 8 for selecting one of the divided output voltages divided by the potentiometers 7 ₁ , 7 ₂ , 7 ₃ , and an encoder 11 ( For example, TC74HC148A). Here, the analog switch circuit 8 is configured to select one of the divided voltages based on the output of the encoder 11 described later.

The output voltage preset circuit section B further includes a buffer amplifier 9 to which the divided output voltage selected by the analog switch circuit 8 is input, and the output voltage of the buffer amplifier 9 is composed of a resistor 2 and a resistor 3. It is applied as a divided voltage to the voltage dividing circuit. The voltage-divided output voltage by the voltage dividing circuit including the resistors 2 and 3 is output as a preset voltage. Presets voltage and detects an output voltage E ₀ and the difference is supplied to the differential amplifier 5 is preset voltage and the output voltage E _0, and controls the V _CE Tran register 1 by the output voltage of the differential amplifier 5.

Furthermore, the output voltage preset circuit section B includes a preset switch 10 for applying the potentials of the terminals P ₁ , P ₂ , and P ₃ to the encoder 11. The encoder 11 has a terminal P of the preset switch 10. The potentials of ₁ , P ₂ , and P ₃ are received and encoded, and the encoded output is supplied to the analog switch 8 to select the divided voltage.

In the present embodiment, the preset switch 10 is provided, for example, on the panel surface of the housing in which the continuous control type DC stabilized power supply circuit is housed, and the terminals P ₁ , P ₂ and P ₃ are preset switches 10. A common terminal for selecting one of the common terminal of the preset switch 12 and the preset switch 12 which is separately connected to the terminals P ₁ , P ₂ and P ₃ of the Is provided with a selection switch 13 which is grounded, and the selection switch 13 is configured to select either the preset switch 10 or the preset switch 12.

The operation of the present embodiment configured as described above will be described. The divided output voltage selected by the analog switch circuit 8 is applied via the buffer amplifier 9 to the voltage dividing circuit composed of the resistors 2 and 3 to be divided. The difference between the preset voltage formed by this voltage division and the output voltage E ₀ is detected by the differential amplifier 5, V _{CE of} the transistor 1 is controlled based on the output of the differential amplifier 5, and the output voltage E ₀ is controlled. Is controlled to a preset voltage.

In this case, assuming that the preset switch 10 is selected by the selection switch 13, according to the output of the encoder 11 based on the position of the contact piece of the preset switch 10, for example, the contact piece is connected to the terminal P ₁ When the contact piece is in contact with the terminal P ₂ , the partial output voltage from the potentiometer 7 ₁ is in contact, and when the contact piece is in contact with the terminal P ₂ , the partial output voltage from the potentiometer 7 ₂ is in contact with the contact piece. Is connected to the terminal P ₃ , the divided output voltage from the potentiometer 7 ₃ is selected by the analog switch circuit 8, and the preset voltage is selected.

However, even if the contact piece of the preset switch 10 is switched to change the selection of the preset voltage, there is no uncertain state in the encoded output of the encoder 11 at the time of switching, and as a result, analog output based on the output of the encoder 11 When the divided output voltage is selectively changed by the switch circuit 8, neither overshoot nor undershoot occurs in the output from the analog switch circuit 8. Therefore, the preset voltage is switched stepwise without overshoot and undershoot as shown in FIG.

The same applies when the preset switch 12 is selected by the selection switch 13. When the preset switch 12 is selected by the selection switch 13, the preset voltage can be switched by the preset switch 12 at a remote position apart from the position of the continuous control type DC stabilized power supply circuit.

In the above description, the case where the output is voltage has been described as an example, but the present invention can also be applied to the case where current output is used. In the case of current output, the output current is converted into a voltage, the difference between the converted voltage and the reference voltage is detected, and V _{CE of} the transistor 1 is controlled based on the detected difference. It may be configured in the same manner as in the case of the voltage output described above and changed in a stepwise manner.

[0021]

[Effect of the device]

 As described above, according to the present invention, the reference voltage is divided by a plurality of voltage dividing circuits, one of the voltage divided outputs is selected by the analog switch circuit, and one of the outputs of the plurality of voltage dividing circuits is designated. The analog switch circuit is controlled by the encoder that receives the output of the specifying unit to select the output of the voltage dividing circuit specified by the specifying unit, so that the divided output voltage specified by the specifying unit works together. The encoder output is selected by the encoder and analog switch circuit, and in this case, the output of the encoder does not become indeterminate when the selected divided voltage is switched by the designating means, and overshoot or undershoot of the preset value occurs during switching. Does not occur, and output voltage and output current have overshoot or undershoot when the preset value is switched. There is an effect that had. Furthermore, the structure for this is also simple.

[Brief description of drawings]

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

FIG. 2 is an explanatory diagram showing a state during preset voltage switching according to an embodiment of the present invention.

FIG. 3 is a block diagram showing a configuration of a conventional example.

FIG. 4 is an explanatory diagram showing a state at the time of switching a preset voltage in a conventional example.

[Explanation of symbols]

A Continuous control method DC stabilized power supply main circuit section B Output voltage preset circuit section 1 Transistor 4 Reference voltage source 5 Differential amplifier 7 Preset potentiometer 7 _{1 to} 7 ₃ Potentiometer 8 Analog switch circuit 10 and 12 Preset switch 11 Encoder 13 Selection switch

Claims (1)

[Scope of utility model registration request] 1. A continuous regulated direct current stabilized power supply circuit capable of presetting an output voltage or an output current, wherein a plurality of voltage dividing circuits for dividing a reference voltage and one of the divided voltage outputs from the plurality of voltage dividing circuits. An analog switch circuit for selecting one of the plurality of voltage dividing circuits, a designating unit for designating one of the outputs of the plurality of voltage dividing circuits, an output of the designating unit as an input, and the output controls the analog switch circuit to designate by the designating unit. A continuous control method direct current characterized by controlling the output voltage or output current based on a preset voltage based on the divided output voltage selected by the analog switch circuit, and an encoder for selecting the output of the divided voltage circuit. Stabilized power circuit.