JPS626312A - Dc stabilized power unit - Google Patents

Abstract

PURPOSE:To prevent a hunting phenomenon and to stabilize the output voltage concurrently with impression of the input voltage, by providing an automatic varying circuit for output voltage to a DC stabilized power unit. CONSTITUTION:When the non-stabilized DC voltage is impressed to the input terminals 1 and 2, a reference voltage generator 6 of a constant voltage regulator 5 works to generate the stabilized DC current voltage VB at a point B. This voltage VB is supplied to an error amplifier 7 together with the output voltage VF. Thus the DC voltage Vout of a fixed level is always produced between terminals 3 and 4 via a transistor 8. Here, an automatic varying circuit 11 for output voltage consists of resistances 13-16, 19 and 21 and capacitors 17 and 20. While a switch 18 is provided to an automatic varying terminal 12 for output voltage. Thus, the output voltage is automatically varied by the short circuit of the switch 18. Thus the stable reference voltage VBX is supplied to the amplifier 7 concurrently with application of the input voltage. In such a way, the stable output voltage Vout is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a DC stabilized power supply device, and particularly to a power supply device having a function of making the output voltage variable by an external signal.

[Background of the invention]

A conventional circuit configuration will be described with reference to FIG. 3 as a method for automatically varying the DC output voltage of a DC stabilized power supply device stepwise from a normal voltage value to a higher potential value or a lower potential value.

Reference numeral 1.2 in the figure is an input terminal, and when an unregulated DC voltage (VrN) is applied to this input terminal, a voltage is also applied to the point A of the constant voltage regulator 5, so the reference voltage generator 6
operates, and a certain stabilized DC voltage (VB) is generated at point B. Furthermore, this voltage is resistor 13 (resistance value R5), resistor 14 (resistance value R6), resistor 15 (resistance value R7), resistor 1
6 (resistance value Rs) and the DC voltage VBX is applied to the non-inverting input terminal of the error amplifier 7. At the same time, transistor 8 is driven and a certain voltage (VF
) occurs. This DC voltage vF is applied to the resistor 9 (resistance value Ra
) and resistor 10 (resistance value R4').
A voltage of R4+13 is applied to the inverting input terminal (point E) of the error amplifier 7, and is always compared with the voltage at point D, and a constant DC voltage of BX is always present between terminals 3 and 4. VOUT--Kv(R4+R3)"
It is controlled so that l occurs. As a method of varying the output voltage of such a DC stabilized power supply device, the output voltage CVOUT=R4+R3'l K Oite, V
A method is used to change RX. That is, if VBX is increased, the output voltage VOUT will also be increased, and if VBX is decreased, the output voltage VOUT will also be decreased. In this method, the resistors 13, 14, 15, and 16 provide the DC voltage Vu.(R7+Rs) voltage vBX=R5+R6+R7+R8 at the steady state point. In this state, the output voltage variable terminals 12 (terminals G, H, I) that can be easily connected from outside the DC stabilized power supply device are connected to both ends of the resistor 13 and the resistor 16.

When terminals G and H of J) are short-circuited using switch 18 or relay contact, the DC voltage VBX at point B becomes -vB・(R7
10R8) vBX=Rs+R7+R8, and at the same time, the output voltage votr'rBX is also given by VOUT=]7(R4+Ra) and becomes high.

When terminals ■ and 5 are shorted, DC voltage at point B Vsx = VB
-(R7) is given by R5+R6+R7 and becomes low. i.e. resistance 9
．． Resistance 10. Resistance 13. By appropriately selecting the resistor 14, a desired voltage increase and voltage drop can be achieved.

However, although this method is inexpensive, since the terminals are instantaneously short-circuited using a switch or the like, the output voltage also increases or decreases instantaneously, resulting in feedback with a delay in operation time as shown in Figure 3. A DC stabilized power supply with a loop has the drawback that a hunting phenomenon appears in the output voltage every time an output variable operation is performed, and an oscillation phenomenon of the entire feedback loop due to the hunting phenomenon of the output voltage appears. Because it is difficult to increase the stepwise variable range, the conventional technology
As shown in the figure, the capacitor 17 (capacitance C) is connected to a DC voltage Vn
If the terminal G and terminal H are shorted by connecting between the output terminals of x, charging current will flow to the capacitor tC.

The step change caused by the switch 18 is relaxed.

Changes to Next, when the switch 18 is changed from the short-circuited state to the open state, the resistor 13 is present in the circuit, and the voltage VBX changes from the voltage VBU to the voltage VBN. However, since the charging current to the capacitance C of the capacitor 17 described above is discharged here, the voltage VBU changes slowly to the voltage VBN, and finally reaches the voltage VBN. Similarly, the output voltage VO changes from VBD to VBN between terminals I and 5.
UT is also determined by slow changes. However, no consideration is given to the time when the input voltage VIN is applied.

When the input voltage vIN is applied, the DC voltage X becomes the DC voltage VBN which lags behind the input voltage VIN due to the capacitor 17 for alleviating stepwise changes in the output voltage. Also, the output voltage VOUT is VBN(Ra +R4
) Since vOUT=R4, the output voltage voty'r also reaches a steady state with a delay from the input voltage VIN, like the voltage VBN. In other words, the capacitor 17 is used to alleviate stepwise changes when automatically varying the output voltage.
(capacitance C) has an adverse effect, and the stabilized output voltage VOUT is not outputted immediately after the input voltage VIN is applied. Furthermore, when increasing the degree of relaxation of step changes during automatic variation of output voltage VOUT, capacitor 1
The capacitance C of 7 becomes larger, and the stabilization of the output voltage VO [JT becomes even slower. Including the above, it was difficult to stabilize the output voltage quickly.

[Purpose of the invention]

An object of the present invention is to avoid the delay in stabilizing the output voltage when an input voltage is applied, which was a drawback of the prior art.

The object of the present invention is to provide an automatic output voltage variable circuit that can change the stabilized output voltage almost simultaneously with the application of the input voltage.

[Summary of the invention]

The advantage of the conventional technology is that even if the output voltage is automatically varied, it can be varied without causing any negative effects such as hunting phenomenon on the output or oscillation phenomenon on the device, but the disadvantage is that the output voltage is not stabilized when the input voltage is applied. There are cases. The present invention utilizes the above-mentioned advantages as they are, and obtains a stable output voltage almost simultaneously with the application of the input voltage.

[Embodiments of the invention]

FIG. 1 is a diagram showing a circuit of a DC stabilized power supply device provided with an automatically variable output voltage terminal, which is an embodiment of the present invention.

Since the circuit configuration and output voltage stabilization operation are almost the same as the conventional one, only the points that are different from the conventional one will be described. In FIG. 1, reference numeral 11 represents an automatic variable output voltage circuit according to the present invention, and a resistor 13. (Resistance value Rs)14. (Resistance value R7
') 15, (resistance @R9) 16, (resistance value R1o)
19. (Resistance value Ru)21. (resistance value R12) and capacitor 17° (capacity tcx) 20, (capacity flc2
).

Reference numeral 12 denotes an output voltage automatic variable terminal, and the output voltage is automatically varied by short-circuiting between G and H67 or between I and J pins of this terminal with a switch 18. The output voltage between output terminals 3 and 4 is sticky during steady state in FIG. Here, for the following explanation, the concave resistance Ω is expressed as VmNr.

Rs + R7 is expressed as VBDI.

In this state, if you short-circuit between G and H pins of the output voltage automatic variable terminal, the capacitor 17 (capacitance C1) will be connected to the resistor 1.
9 (resistance value Ru), the stepwise change caused by the switch 18 is alleviated, and the voltage VBX applied to the non-inverting input terminal (point D) of the error amplifier 7 slowly changes from the voltage VBNr to the voltage VBUI. As a result of this change, VOUT:vBUI・(R3+R4),K will finally change. Next, if the switch 18 is changed from the short-circuited state to the open state 1 (resistance value R9'), the resistor 15 (resistance value R9'
) A charging current flows to the capacitor 17 via VB
Slowly changes from UI to VBN I.

Eventually you will reach VBNI. Also, when the I-J pins of the output voltage automatic variable terminal 12 are short-circuited by the switch 18 and then opened, VBX changes from VBNI to VBDI and from VBDI to VBN r due to the discharging and charging current from the capacitor 20. VBX slowly to
(R3+R4) Change. The voltage VOUT determined by -4-111 also changes slowly. That is, the output voltage can be output by a short circuit between the output voltage automatic variable terminals G and H bins of the switch 18. Figure 2 shows the contents of these operations over time, and shows the contents of operations when the output voltage automatic variable terminals G and H bins and I and J pins are short-circuited or opened. Even if the change is a step change, the fluctuation of VBX changes in proportion to the charge/discharge curve of capacitors 17 and 20,
This shows that the VOUT voltage changes gradually in proportion to the change in VBX.

In addition, early stabilization of the output voltage when input voltage is applied, which was not possible in the conventional technology in combination with the above-mentioned advantages, is achieved by designing the relationship R52R7, R9=Rlo and C1:C2, and each Assuming that there is almost no variation in the constants of the resistor and each capacitor, the voltage VBX can supply the stable non-inverting input voltage of the error amplifier 7, that is, VBN, almost simultaneously with the application of the input voltage, and -BNR3
The output voltage VOUT determined by +R41- can also obtain a stable output voltage almost simultaneously with the application of the input voltage VIN.

Furthermore, in order to adjust the degree of relaxation of step changes when automatically varying the output voltage VOUT, capacitors 17 and 2 are used.
0 capacitance CI, C2 or resistance value R of resistors 19 and 21
This is possible by changing u and R12.

When changing constants, R5:R7, R9:R10, Ct =
There is an advantage that as long as the relationship C2 is maintained, a stable output voltage VOUT can be obtained almost simultaneously with the application of the input voltage.

:Effects of the Invention] By adopting the present invention as described above, even if the output voltage is automatically varied using a simple signal conversion element such as a switch, there will be no knocking phenomenon in the output, oscillation phenomenon in the device, etc. It is possible to provide a DC stabilized power supply device with an automatic output voltage variable function that does not exhibit any adverse effects and can obtain a stable output voltage almost simultaneously with input voltage application.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of an embodiment of the present invention, FIG. 2 is an explanatory diagram of the operation contents, and FIGS. 3 and 4 are circuit diagrams according to the prior art. 6... Basic voltage generator, 7... Error amplifier. 8...Series control transistor. 11...Variable output circuit, 12...Variable output voltage terminal,

Claims (1)

[Claims] 1. In a DC stabilized power supply device that includes a constant voltage regulator that detects the difference between a reference voltage and an output voltage using an error amplifier, and controls and stabilizes the output voltage according to the difference, the reference voltage is controlled by two resistors. The voltage divided by the resistor is used as the target reference voltage, and a circuit consisting of a series connection of a resistor and a capacitor is connected in parallel to each of the resistors, and both ends of each capacitor are short-circuited through the resistor to obtain the target voltage. A DC stabilized power supply device characterized by varying the reference voltage and varying the output voltage.