JPS59205621A - Power supply circuit - Google Patents

Abstract

PURPOSE:To miniaturize a power supply circuit and to attain the use of this circuit in both Japan and foreign countries where a different voltage is applied for power supply by turning off a switch circuit when the rectified voltage is higher than a prescribed level to avoid the input of the voltage higher than the prescribed level to a constant voltage circuit. CONSTITUTION:When the rectified voltage VDS exceeds the Zener voltage VZD3 of a Zener diode ZD3 of a switch control circuit 6, a capacitor C6 is charged via a resistance R13. When the charging voltage of the C6 reaches the gate trigger voltage VT of a thyristor SCR, the SCR is turned on. At the same time, a switch circuit 5 consisting of transistors TR Q4 and Q5 is turned off to prevent the input of the high level part of VDS to a constant voltage circuit 3. As a result, it is avoided that the voltage higher than a fixed level is fed to the circuit 3. Thus the breakdown strength is reduce for a capacitor C1 and also the area between the collector and the emitter of a TRQ1. This attains the miniaturization of a power supply circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a power supply circuit that supplies a constant voltage to a load circuit.

[Background technology]

Conventionally, as shown in Figure 1, an AC power supply (1) is connected to a rectifier circuit (2) using a diode (D□).
), the rectified voltage VDO is supplied to the load circuit (4) via a constant voltage circuit (3), and this constant voltage circuit (3) includes a step-down resistor (R1) and a smoothing capacitor. (C1), control transistor (Ql), zener diode (ZDi) for voltage setting, bias resistor (R
Q) and another capacitor +j (C2) are formed, and a voltage vc is supplied to the load circuit (4), which is set based on the zener voltage of the zener diode (ZDI). ,there was. By the way, in such a conventional example, if the permissible fluctuation range of the power supply voltage vAc of AC power supply (11) is set to be large (for example, 80V to 140V), the power consumption due to the resistance (Rl) when using the GT dog will be large. In addition, there is the problem of reduced reliability due to heat generation, and the casing, collector-emitter breakdown voltage of the transistor (Ql), collector loss, and capacitor (C1) breakdown voltage must be set large, which is expensive and requires a large size. There is a problem in that it is not possible to obtain a small power supply circuit at low cost due to the use of large components.

[Purpose of the invention]

The present invention has been made in view of the above points, and it is an object of the present invention to provide a small-sized power supply circuit at low cost.

[]Genmei's disclosure]

Figures 2 to 6 are Ki-ni)-! Power supply circuit using IJ (A
) using /i7. This shows an example of a multiple-operation type switch device, in which (10) ri is the main picture, (l is the slave unit, and the dedicated line (12) from the main picture (10) is connected to By connecting multiple slave units tli), you can control the oscilloscope from a place with a large load (13) by operating the main picture (1o) or the slave unit (one operation switch (a) (and b)). As shown in Figure 6, the parent picture (10) ζJ, as shown in Figure 6, ]n7!C+'j (C3) is 1j double-row connection → negative ti!I side] Single winding latching relay (Ry
x) Main circuit (hybrid) consisting of two-way three-terminal thyristor (l) (1.20) and operation switch (if) a). 2-winding latch control (Ry2), which is excited by turning on, a light emitting diode (LDI) for operation indication (LD2>), a diode for blocking the door (D2) (D3), and resistors (Ra) to (R6). and ], an operating circuit consisting of a digital sensor (C4) and (C5)
), 1-large υ resistor (C2) (C3) and resistor (
A power short-circuit prevention circuit consisting of R7) to (R10);
The power supply circuit (A) according to the present invention is composed of a constant voltage circuit (3) that is the same as the conventional example, transistors (C4) (C5), diodes 1 (D4), and a resistor (
R11) (R*) The rectified voltage ■Dc is manually input through the switch circuit (5) consisting of a reverse blocking type, '3@child thyristor (SCR), Zener diode (Zn3), ) and resistors (R13) (R14) controls the switch circuit (5), and when the rectified voltage VOC becomes higher than the preset voltage, the switch circuit (5) ) is turned off. In the figure, (rm) (rlb) are latches, Jj
The contacts of the relay (Ryl), (rm) (rPb) are the contacts of the latch (ZNR) Ii miscellaneous nonlinear resistor (Ra
) (Rgb) is a resistance. Figures 41 and 5 are diagrams showing the structure of the parent image (101; the example is body @l)
and the case consisting of the cover country, (33) is the mounting frame, the needle is the operation circuit block, I4 is the hybrid contact circuit' block, (the rope is terminal -3 + Kotoku, (, Ma) is the terminal cover, (3' 7) is a hasidor, (38) is a fixed spring, (
39) is a stopper, and (+0) is a coil spring. In this case, the handle 0'7) is held swingably around the protrusions (37a) on both sides, and there are operating switches (jc & rt+) on both legs that can be pressed with Tb). As shown in FIG. )
Then, check the voltage of the dedicated line (12) and check the voltage of the load (13).
jkl with an operation display circuit (23) that displays the operation status of
The operation display circuit (4 is a diode bridge (DB)
), zener diode (Zn5), l・u, :/jis'i (C6), and light emitting diode (LD3) (Lf
),), switch, Fujidaio-1mi(1)6) and]
′:) resistance (C7) and resistance (R15) - (R17
) and has matured in form.

Below, I will congratulate you on the actions of the central figure. i1, parent equipment (1
0) operating circuit V, 1) latch shift relay (Ry2)
When the contacts (r) and (r21)) are switched to the NC side as shown in the figure, the rough contact 1 and no (Ryx) contacts (rx-
) (rlb) and the thyristor (I゛) are off, the load 0 (6) does not operate, the light emitting diode (LD2) for indicating off moxibustion lights up, and the light emitting diode (LDl) for indicating moxibustion lights up. is turned off, indicating that the load VI (6) is in an off state on the main picture (1o) side. At this time, a Zener diode (Zn2) with a low Zener voltage is connected to the constant voltage circuit (3).
), a low constant voltage V Cl (aV) is output from the slave unit (1) through a dedicated line (I"2J). Here, the operation display circuit (23 ), the zener voltage of the zener diode (Zn2) is set higher than the constant voltage VCI (33V), and the !- transistor (C6)
is turned off, so the light emitting diode (LD
3) goes out and the light emitting diode (
LD4) lights up to indicate that the load image is off.
display on the remote side. In addition, in this state, condensation +
I' (Cps) (C4) has enough charge accumulated to drive I'lI:i: latch shift relay (Ry) (Ry2). Next, the main picture (1o) or the slave picture (11)
When the operation switch (10a,
y2) through the set coil Ls of the flow contact (r+l!
a) (ra) switches to the NO side. Then, the charge of the capacitor (C3) flows through the coil (r, 1> of the latch relay (Ryx), and the contact (rla) is turned on, which turns on the thyristor σ).
xb) turns on and the load (6) starts operating. At this time, the light-emitting diode t: (LD
I) lights up. At the same time, the Zener diode (ZD2) of the constant voltage circuit (3) is disconnected, so the constant voltage circuit (3)
) outputs a constant voltage Vc2 (48V) based on the Zener voltage of the Zener diode (ZDI), and the voltage is applied to the slave unit (1) via the dedicated line (12J), and the transistor (Q6) is activated. and a light emitting diode (L) for display.
D3) lights up. At the same time, the operation switch (lOa) (
When na) is turned on, the charge accumulated in the capacitor (C5) flows through the reset coil (LR) of the latch relay (Ry2), and the contact (r2a) (ra)
is reversed, and a capacitor (C3) is connected to the excitation coil (Ll) of the latch (Ryl) with the polarity shown.
The charging current of the capacitor (C3) to be charged flows through the contact (r
m) (r1°C) is turned off and the load (13) is turned off. In the same way, either operation switch (IDa) (n
Each time b) is operated, the load (13) is turned on and off.

By the way, in the operation of the power supply circuit according to the present invention, as shown in the vJT diagram, the rectified voltage VDC is equal to the zener voltage VZD3 (
4'7V), the capacitor C6) is charged via the resistor (R13), and when the charging voltage of the ]'J decapacitor) reaches the gate voltage vT of the thyristor (SCR), the thyristor (SCR) The switch circuit (5) consisting of transistors (Q4) and (Q5) is turned off to prevent the high voltage portion of the rectified voltage VDO from being input to the constant voltage circuit (3). Therefore, the constant voltage circuit (
3), the voltage on the -step is not input, and the constant voltage circuit (3)
) of the capacitor (C1) and the transistor (Q
l)] The breakdown voltage between the rectifier and the collector and the collector loss can be reduced, and the cost and size can be reduced. In addition, the resistor (R14) and capacitor (C6) keep the gate current of the thyristor (SCR) flowing during the period after the half-cycle thyristor (SCR) is turned on by discharging the capacitor (C6). Yorina 1
set directly. This means that after the thyristor (1゛5CR) turns on, the anode current flowing through the resistor (R12) may be lower than the holding current (this means that the resistor (R12) is the base of the transistor (Q5). Since only current flows, this resistor (R12) can have a high resistance and power loss can be reduced.Also, the capacitor (C6) can be omitted as shown in Figure 8. Of course it goes without saying.

FIG. 9 shows another embodiment, in which the thyristor (SCR) in the embodiment of FIG. 8 is replaced with a transistor (Ql), and a noise prevention interface (LN) and cosiden t (CN) are provided. It is.

Now, as shown in Figure 9410 (a), the constant voltage circuit (3) is inputted with a voltage in which the part of the rectified voltage VDc that is higher than the Zener voltage VD3 is cut, and the voltage is input to the constant voltage circuit (3).
A charging current IC as shown in Figure 10 (b) flows through the IC, and phase control noise is generated when the charging current c steeply rises and falls. [Effects of the Invention] As described above, the present invention rectifies the rectified voltage of the AC power supply through the constant voltage circuit. In a power supply circuit configured to supply a load circuit, a switch that inputs a rectified voltage to a constant voltage circuit via a switch circuit and turns off the switch circuit when the rectified voltage becomes higher than a preset voltage. It is equipped with a control circuit, and the voltage exceeding the preset voltage is not input to the constant voltage circuit, so even if the permissible fluctuation range of the AC power supply voltage is increased, the constant voltage circuit will not be affected. There is no need to increase the breakdown voltage of transistors used for This has the advantage of providing a power supply circuit that can be shared by multiple users.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of a conventional example, Fig. 2 is a schematic configuration diagram of a multi-point operation type switch device, Fig. 5 is a main part circuit diagram of a switch device equipped with a power supply circuit according to the present invention, and Fig. 4 is the same as above. Fig. 5 is an exploded perspective view of the main parts of the above, Fig. 6 is a circuit diagram of the main parts of the same, Fig. 7 is an explanatory diagram of the operation of the same, and Fig. 8 is a circuit diagram of another embodiment. , f; 0 Figure I''i A circuit diagram of another embodiment, and Figure 10 is an explanatory diagram of the same operation as above. +1+ is an AC power supply, (3) is a constant voltage circuit, (4) is a load circuit, (5) is a switch circuit, and (6) is a switch control circuit. Agent Patent Attorney Ishi 1) Choshichi

Claims (1)

[Claims] +1) i In a power supply circuit configured to supply a rectified voltage obtained by rectifying an AC power source to a load circuit via a constant voltage circuit, the rectified voltage is input to the constant voltage circuit via a switch circuit, and the rectified voltage is set in advance. 1. A g source circuit comprising a switch control circuit that turns off the switch circuit when the applied voltage increases.