JPH0475116A - Dc constant voltage source - Google Patents

Abstract

PURPOSE:To surely perform the operation of a positive and negative sharing power source three-terminal regulator and to realize a DC constant voltage source with high reliability by comprising a system without receiving the influence of an opposite side voltage by separating a positive voltage three-terminal regulator from a negative voltage three-terminal regulator by a relay. CONSTITUTION:A first relay 6 is connected to the output side of the positive voltage three-terminal regulator 3, and a second relay 7 to the output side of the negative voltage three-terminal regulator 10, and the serial connection part of first relay contacts 6b, 6c and second relay contacts 7b, 7c is connected between the output side of respective three-terminal regulator and a load 8. Thereby, the first and second relays 6, 7 are operated by outputting a voltage to the output of each of the three-terminal regulators 3, 10, and a source voltage is supplied to the load 8 via the relay contacts 6b, 6c, 7b, and 7c, therefore, latch down is perfectly prevented occurring, and the DC constant voltage source with high reliability is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a DC constant voltage power supply for electronic equipment that obtains a stabilized power supply voltage lower than the input DC voltage.

[Prior art] Figure 2 shows, for example, the conventional 3 shown in the manufacturer's manual.
In Figure 9, which is an example of the use of a terminal regulator, (1)
is the positive voltage input terminal, (2) is the ground terminal positive voltage (vl
) is applied between this positive voltage input terminal (1) and the ground terminal (2). (3) is a positive voltage three-terminal regulator that outputs a stabilized positive voltage (v3) smaller than the positive voltage (V,!) when the positive voltage (vl) is manually input.

(4) is a capacitor that removes high frequency ripple voltage from positive voltage (V+), (8) is a capacitor that removes high frequency ripple voltage from positive voltage (V3) and negative voltage (-
L) is the load with the power supply voltage, (9) is the negative voltage input terminal,
The negative voltage (-vzl) is applied between this negative voltage input terminal (9) and the ground terminal (2). (lO) is the negative voltage (-vzl).
A negative voltage 3-terminal regulator that inputs the negative voltage f-vz) and outputs a stabilized negative voltage (-V, ) larger ((absolute value voltage is smaller) than the negative voltage f-vz), f121 is the positive voltage (v
l) and negative voltage f-V2) are input asynchronously, a third diode prevents each of the positive voltage 3-terminal regulator (3) and negative voltage 3-terminal regulator (10) from non-operating due to latchdown, When the input positive voltage (Vl) and negative voltage (-V2) are disconnected, f13a) (13b) allows the residual voltage of each capacitor (4b) (4d) to flow, and becomes a positive voltage three-terminal regulator (3). and a fourth diode that protects the negative voltage three-terminal regulator.

Next, the operation will be explained. A method using a three-terminal regulator is often used when both stabilized positive and negative voltages are required as a power supply to the load (8).

If the positive voltage (vl) is applied later than the negative voltage (-L), the negative voltage (-V,) will pass through the load (8) to the positive voltage 3
Positive voltage 3 is applied to the pressure side of the terminal regulator (3)
Since the internal circuit of the terminal regulator (3) may not start up (this is called latchdown), a third diode (12) is installed to prevent this latchdown.
Clear the negative voltage (-V4) using a). The third diode (12b) connected to the negative voltage three-terminal regulator (10) also operates to prevent latch-down in the same manner as described above.

[Problems to be Solved by the Invention] Since the conventional DC constant voltage power supply is configured as described above, the third diode (12) to prevent latchdown is required.
Therefore, it was necessary to use a material with extremely low forward voltage and good temperature characteristics to clip the three-terminal regulator to a low voltage that would not cause it to become inoperable. Therefore, among the expensive Schottky diodes, one with particularly low forward voltage (and good temperature characteristics) must be used as the third diode (12).

This invention was made in order to solve the above-mentioned problems, and is to cut off the voltage applied from each other side through the load to the output side of a positive voltage and negative voltage 3-terminal regulator until the self-regulating 3-terminal regulator operates. The aim is to obtain a DC constant voltage power supply that can

[Means for Solving the Problems 1] The DC constant voltage power supply according to the present invention connects a first relay to the output side of a positive voltage three-terminal regulator and a second relay to the output side of a negative voltage three-terminal regulator, The first relay contact and the second relay contact are connected between each three-terminal regulator output side and the load.
This is a series connection of relay contacts.

[Operation: The power supply voltage is not connected to the load by the first and second relays until the input voltage is applied to each of the positive voltage three-terminal regulator and the negative voltage three-terminal regulator and each operates.

The first and second relays operate by outputting a voltage to each three-terminal regulator output, and since the power supply voltage is connected to the load through the relay contacts, it is possible to completely prevent latchdown.

[Example 1] An example of the present invention will be described below with reference to the drawings. 1st
In the figure, (5) is the first diode that clips the noise generated when the first relay operates, (6) is the first relay connected to the positive voltage 3-terminal regulator (3), and (7) is the first diode that clips the noise generated when the first relay operates. The second connected to the negative voltage three-terminal regulator
relay, (11) is the second diode that clips the noise generated when the second relay operates.

Apply a positive voltage (Vl) to the positive voltage 3-terminal regulator (3) and negative voltage 3-terminal regulator (10) at any timing
) and negative voltage (v2) are input, the positive voltage 3-terminal regulator (3) and negative voltage 3-terminal regulator (
The output positive voltage (V3) and negative voltage (-V4) of 10) are connected in series with relay contacts (6b), (7c) and (
Since it is cut off by 7b) and (6c), it can rise without being affected by the negative voltage (-L) and positive voltage (3) of each other side. Positive voltage (V3) and negative voltage (-L
) rises, the voltage causes the first relay (6) to
and the second relay (7) operates and the first relay contact (6
b), the second relay contact (7c) and the second relay contact (7c)
7b) and the first relay contact (6c) are each activated. According to the above, the positive voltage (v3) and negative voltage (-L) are connected to the load (8)
The above operation can prevent a negative condition called ``depression'', which occurs when the device is connected to a terminal and a current can flow therethrough.

In the above embodiment, an electro-mechanical movable relay f6) is used.
f7), but a movable relay (6
) A non-movable semiconductor relay may be used instead of f7).

[Effects of the Invention] As described above, this invention separates the positive voltage 3-terminal regulator and the negative electronic 3-terminal regulator by a relay when the power is turned on, so that the positive voltage is completely unaffected by the voltage on the other side. - The operation of the negative common power supply three-terminal regulator is reliable, and it is possible to provide a reliable DC constant voltage power supply.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of a DC constant voltage power supply according to the present invention, and FIG. 2 is a circuit diagram showing a conventional embodiment. El) is a positive voltage input terminal, and (2) is a ground terminal. (3) is a positive voltage three-terminal regulator, (4) is a capacitor, (5) is the first diode, (6) is the first relay, (7) is the second relay, (8) is the load, ( 9) is the negative voltage input terminal, flO) is the negative voltage 3-terminal regulator, (11) is the second diode, (12) is the third
(14) is the fourth diode. Note that the same line numbers in Figure 1 indicate the same or equivalent parts.

Claims (1)

[Claims] In a DC constant voltage power supply using a 3-terminal regulator that inputs positive and negative DC voltages and outputs stabilized arbitrary positive and negative DC voltages, the positive voltage 3-terminal regulator and the output of this positive voltage 3-terminal regulator a first relay connected to the terminal; a first diode connected in parallel to the first relay; a first relay contact connected between the positive voltage three-terminal regulator and the load circuit; a second relay contact connected in series to the relay contact of the negative voltage three-terminal regulator; a second relay connected to the output terminal of this negative voltage three-terminal regulator; and a second relay connected in parallel to this second relay. A second diode, a second relay contact connected between the negative voltage three-terminal regulator and the load circuit, and a first relay contact connected in series to the second relay contact. DC constant voltage power supply.