JPS60243926A - Off timer circuit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an off-timer circuit used in television receivers and the like.

[Prior Art] Conventionally, in television receivers and the like, there has been a power supply control circuit shown in Figure @3. In the figure, (1) is a power transformer, which includes AC input terminals (2a), (2b), main output terminals (3a), (3b), and sub-output terminals (4).
a) and (4b). Main output terminal (3a)
, (3b) between which is the contact (51) of the electromagnetic relay (5)
is inserted. The sub output terminal (4a) is a diode (
6) and a capacitor (7) to a power input terminal (8) of a control circuit (8). In the control circuit (8), (1o) is a signal sending terminal;
(11) is a signal acquisition terminal, and both these terminals (10
) and (11) are short-circuited and connected by the key switch (12). Further, (13) is a power supply control signal output terminal, which is connected to the coil (52) of the electromagnetic relay (5). The control circuit (8) is mainly composed of a microcomputer, and in addition to the illustrated signal sending terminal (10), signal receiving terminal (11), and power control signal output terminal (13), there are other terminals other than power control. Signal output terminals, signal acquisition terminals with control functions,
It has a control signal output terminal (none of which is shown).

Next, the operation will be explained. When an AC voltage is applied to the AC input terminals (2a) and (2b) of the power transformer (1), the DC drive voltage rectified by the diode (6) and capacitor (7) is applied to the power input terminal (2b) of the control circuit (8). 8). Now, when the key switch (12) is pressed, the signal output terminal (lO) and the signal intake terminal (11
) is connected, and the control circuit (8) detects this and performs predetermined processing. As a result, the power supply control signal output terminal (1
3), a signal with a polarity opposite to the state before the key switch (12) was pressed is sent to the coil (5) of the electromagnetic relay (5).
2), turns on or off the contact (51) of the electromagnetic relay (5), and connects the main output terminals (3a) and (3).
b) Control the connection and disconnection of the voltage between.

In the above power supply control circuit, the main control is performed by a microcomputer, etc., so in order to operate the off timer, it is necessary to change the program inside the control circuit (8) or change the electromagnetic relay (5). It was necessary to use other control circuits to drive the device. Such additional control circuits may provide outputs that are functionally contradictory to those of the basic control circuit, resulting in low reliability.

[Summary of the Invention] This invention has been made to eliminate the above-mentioned conventional drawbacks, and includes a configuration in which a timer circuit that is activated by a signal from a control circuit is provided, and the output from this timer circuit is taken into the control circuit again. By doing so, the purpose is to provide a highly reliable off-timer circuit.

[Embodiments of the invention] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a circuit diagram showing an embodiment of an off-timer circuit according to the present invention. In the figure, the same parts as in FIG. 3 are given the same reference numerals, and the explanation thereof will be omitted. In FIG. 1, the control circuit (8) includes a second signal sending terminal (14) and a second signal receiving terminal (15). Both these terminals (+4
) and (15) are short-circuited and connected by a key switch (16). (17) is a timer control signal output terminal, and its output is from the timer circuit (18).
) is given to

On the other hand, the first signal sending terminal (10) is connected to the transistor (1
The emitter of 9) and the first signal intake terminal (11) are respectively connected to the collector of the transistor (19), and the base of the transistor (19) is connected to the collector of the transistor (21) via the resistor (20), and Resistance (20),
(22) to the power input terminal (8) of the control circuit (8).
) are connected to each other. Transistor (21) (
7) The emitter is grounded and the base is connected to the timer circuit (
18) is connected to the timer output terminal (23).

Further, the main output terminal (3b) is connected to the power supply terminal (26) of the timer circuit (18) via a rectifier circuit consisting of a diode (24) and a capacitor (25).

Next, the operation will be explained. When the power supply is connected, a power supply voltage is applied to the power supply terminal (26) of the timer circuit (18). When the key switch (18) is pressed now, the second signal sending terminal (14) and the second signal receiving terminal (15) are connected, and the timer control signal output terminal (1
7) outputs a timer control signal.

This control signal is given to the timer circuit (18), and the timer circuit (18) starts timer operation.

After a predetermined time, a timer output signal is applied from the output terminal (23) of the timer circuit (18) to the base of the transistor (21), and the transistor (21) becomes conductive.

When the transistor (21) becomes conductive, the transistor (18) also becomes conductive, and the first signal sending terminal (1
0) and a signal acquisition terminal (11) are connected. As a result, the control circuit (8) detects this and performs predetermined processing, and connects the power supply control signal output terminal (13) to the electromagnetic relay (5).
) is sent out to turn off the contact (51).

When the contact (51) of the electromagnetic relay (5) is turned off, the power to the timer circuit (18) is also cut off, and the electromagnetic relay (5) continues to be turned off until the key switch (12) is pressed again.

In the above embodiment, the transistor switch is configured as one path, but it is also possible to configure it as two paths as shown in FIG.

In FIG. 2, transistors (27) and (29)
, and a second consisting of resistors (28) and (30).
A switch circuit is provided in parallel with the key switch (16), and an output terminal (23) of the timer circuit (18) is connected to this second switch circuit. On the other hand, the output terminal (23) of the timer circuit (18) is connected to the diode (31
), capacitor (32), and transistor (33)
It is also connected to the first switch circuit via the transistor (33), and the control signal from the timer control signal output terminal (17) is applied to the base of the transistor (33) via the resistor (34). .

In the case shown in FIG. 2, the transistor (27) is made conductive by the timer output signal of the timer circuit (18), and the second signal sending terminal (14) and the signal receiving terminal (1
5), the off-timer operation setting is canceled, the output level of the timer control signal output terminal (17) is lowered, and then the power is turned off. In each of the above embodiments, the key is manually operated. Although only two sets of input terminals are shown, there may be many more input terminals, and although a separate rectifier circuit is provided as the power supply for the timer circuit (18), it is not possible to use the flyback pulses of a television receiver, etc. A DC power source obtained by rectification may also be used.

[Effects of the Invention] As described above, according to the off-timer circuit according to the present invention, there is no need to change the internal program of the control circuit or add any other control circuit, so a highly reliable off-timer circuit can be provided. Can be 4゜

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of an off-timer circuit according to the invention, FIG. 2 is a circuit diagram showing another embodiment of the invention,
FIG. 3 is a circuit diagram showing a conventional power supply control circuit. (8)...Control circuit, (lO)...First signal output terminal, (11)...First signal intake terminal, (13)...
...Power control signal output terminal, (14)...Second signal sending terminal, (15)...Second signal acquisition terminal, (17
)...Timer control signal output terminal, (18)...Timer circuit, (19) transistor, (23)...Timer output terminal. Note that the same reference numerals in the figures indicate the same or corresponding parts. Agent Masuo Oiwa Figure 1 Figure 2

Claims (1)

[Claims] (1) When a control circuit having a first signal sending terminal and a signal taking-in terminal and a second signal sending terminal and a signal taking-in terminal is connected to the second signal sending terminal and signal taking terminal. a timer circuit that starts a timer operation in response to a timer control signal output from a control circuit; and a transistor driven by a timer output signal output from the timer circuit after a predetermined time; In order to cut off power from the control circuit by connecting the first signal sending terminal and the signal taking terminal in parallel with the sending terminal and the signal taking terminal, and connecting the first signal sending terminal and the signal taking terminal through the transistor when the timer output signal is output. An off-timer circuit characterized in that a power supply control signal is output.