JPH0622244A - Rush current limit circuit for television receiver - Google Patents

Abstract

PURPOSE:To obtain a rush current limit(RCL) circuit with high reliability and safety by turning on a power supply for the television receiver when a rush current limiting resistor is opened. CONSTITUTION:When an on/off switch 18 is closed by an on/off switch control signal 26 of a television receiver, a rush current 29 flows through a rush current limiting resistor 16 only for a time in response to the capacitance of a smoothing capacitor 22 connecting to an AC voltage rectifier diode block 19. After the rush current is decreased, a switch 17 closing the rush current limiting resistor is thrown to the position of a standby power transformer 20 to short- circuit the resistor 16 and to give a signal from a standby power transformer 1 to a standby circuit 23. Furthermore, when a standby circuit operating state signal is not switched even after lapse of a prescribed time after a switching signal for the switch 17 is generated, an on/off signal generating circuit 24 detects the occurrence of a fault to turn off the switch 18 and a fault state is displayed on a state display circuit 28 being an RCL circuit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inrush current limiting circuit (hereinafter, RCL circuit (Rush Cur) of a television receiver.
abbreviated as "rent Limiter". ) Is related to.

[0002]

2. Description of the Related Art An example of an RCL circuit of a conventional television receiver is shown in FIG.

The operation will be briefly described. When the AC plug 1 of FIG. 2 is inserted into an AC100V outlet, the standby circuit 9 is activated via the standby power transformer 8.

The standby circuit 9 transmits the standby circuit operating state signal 13 to the television receiver on / off signal generating circuit 14.

The television receiver ON / OFF switch 5 is short-circuited by the television receiver ON signal 11 from the television receiver ON / OFF signal generation circuit 14, and A
The inrush current limiting resistor 2 is provided only for a time corresponding to the capacity of the smoothing capacitor 6 connected to the C voltage rectifying diode block 4.
An inrush current flows through the path of 7 through.

After the inrush current has decreased to near the steady current value, the inrush current limiting resistor both ends short open switch 3
Is short-circuited by the limiting signal 10 to eliminate the heat generation of the inrush current limiting resistor 2 at the normal time.

When the television receiver is turned off, the on / off switch 5 is opened by the television receiver off signal 11 from the on / off signal generating circuit 14 and the inrush current limiting resistor both ends short open switch control signal 10 is provided. As a result, the short open switch 3 is opened.

[0008]

However, according to the above-mentioned conventional configuration, since there is no function of detecting the state of the short-circuit open switch 3 at both ends of the inrush current limiting resistor, the power-on / off switch 5 is turned on when the switch 3 is short-circuited. Is short-circuited and the on-off switch 5 is damaged by an excessive inrush current, or the inrush current limiting resistor 2 is damaged due to heat generation because the current continues to flow constantly with the switch 3 kept open. Had.

The present invention solves the above-mentioned conventional problems. When the power of the television receiver is turned on, the inrush current is always attenuated by the inrush current limiting resistor, and in the steady state, the inrush current limiting resistor is always shorted. If the power cannot be turned on in any state other than the above, and if a constant current continues to flow through the inrush current limiting resistor after the power is turned on, the television receiver is turned off and the state is displayed. It is an object of the present invention to provide a safe and highly reliable RCL circuit for a television receiver.

[0010]

To achieve this object, the RCL circuit of the television receiver of the present invention comprises means for detecting a short-open state at both ends of the inrush current limiting resistor, and the inrush current limiting resistor. Means to turn on the power of the television receiver only when both ends are open, Means to turn off the power of the television receiver when both ends of the rush current limiting resistor in the steady state are not short-circuited, and the contents are displayed. It is configured by means for

[0011]

With the above structure, when the power of the television receiver is turned on, the inrush current is always attenuated by the inrush current limiting resistor, and in the steady state, the inrush current limiting resistor is always short-circuited. In other states, the power cannot be turned on. Further, when the current continues to flow constantly in the inrush current limiting resistor after the power is turned on, the power of the television receiver can be turned off and the state can be displayed.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a configuration in which a standby transformer 1 and a standby transformer 2 detect a short-circuited open state at both ends of a rush current limiting resistor.

In FIG. 1, reference numeral 15 is an AC plug, 16 is an inrush current limiting resistor, and 17 is an open state with both ends of the inrush current limiting resistor 16 being connected to the standby power transformers 20 and 21. Inrush current limiting resistor both ends short open switch, 18 is a television receiver power on / off switch, 19 is a DC rectifier diode block of AC voltage, 20 is a standby power supply transformer 1 through which current flows when both ends of the inrush current limiting resistor 16 are short-circuited, Reference numeral 21 is a standby power supply transformer 2 through which current flows when both ends of the inrush current limiting resistor 16 are open, 22 is a smoothing capacitor, 23 is a standby circuit, 24 is a television receiver power on / off signal generating circuit, and 25 is an inrush current limiting resistor. Both ends are short open switch control signals, 26 is a television receiver power on / off switch control signal, 2
Reference numeral 7 is a standby circuit operating state signal 2 from the standby power supply transformer 2, 29 is a standby circuit operating state signal 1 from the standby power supply transformer 1, 28 is an RCL circuit state display circuit.

The operation of the RCL circuit of the television receiver configured as described above will be described.

When the AC plug 15 of FIG. 1 is inserted into an AC100V outlet, a current flows through the standby power supply transformers 20 and 21 through the switch 17, and the standby circuit 23 supplies the standby circuit operation state signal 2 to the ON / OFF signal generating circuit 24. Tell. On-off signal generation circuit 24
Can turn on the power on / off switch 18 of the television receiver only when the standby circuit operation state signal is 2.

When the ON / OFF switch control signal 26 of the television receiver causes the ON / OFF switch 18 to short-circuit, the inrush current is passed through the inrush current limiting resistor 16 for a time corresponding to the capacity of the smoothing capacitor 22 connected to the AC voltage rectifying diode block 19. Flows on a path of 29.

After the inrush current has decreased to near the steady current value, the short-circuit open switch 1 at both ends of the inrush current limiting resistor 1
7 is switched to the standby power supply transformer 2 side by the short open switch control signal 25, the resistor 16 is short-circuited, and the signal from the standby power supply transformer 1 is transmitted to the standby circuit 23. The standby circuit 23 transmits the standby circuit operation state signal 1 to the on / off signal generating circuit 24.

The on / off signal generating circuit 24 includes a switch 1
If the standby circuit operating state signal does not switch from 2 to 1 within a certain time after the switching signal of 7 is generated, an abnormality is detected, an off signal of the switch 18 is output, and the switch 18 is turned off and the RCL Circuit status display circuit 28
A signal is transmitted to and an error is displayed.

In this way, the short-circuited open state at both ends of the rush current limiting resistor can be easily detected by the standby transformer 1 and the standby transformer 2.

FIG. 3 is an internal block diagram of the television receiver power on / off signal generating circuit 24 of FIG.

A configuration example in which the power source of the television receiver cannot be turned on when both ends of the inrush current limiting resistor are short-circuited, and both ends of the inrush current limiting resistor are open when the television receiver is constantly on. It shows an example of a configuration in which the power of the television receiver is turned off when it is left as it is.

In FIG. 3, reference numeral 30 denotes a time constant signal generating circuit for generating a signal having a time constant corresponding to the smoothing capacitor 22 shown in FIG. 1, 31 denotes a time constant signal and a standby circuit state. OFF signal 2 generation section for generating signal 2, 32 is a television receiver off signal, 36 is a standby circuit operating state signal 2, 37 is a television receiver on signal, 38 is a standby circuit operating state signal 2 and television receiving A television receiver on signal generation unit for generating a television receiver on signal from the television on signal, 35 is a television receiver on signal, 34
Is a control signal for short-circuited open switch at both ends of the inrush current limiting resistor, and 33 is a standby circuit operation state signal 1.

The operation of the on / off signal generating circuit configured as above will be described. The ON signal 35 of the television receiver is generated only by the ON signal 37 input when the status signal 2 is input to the television receiver ON signal generation unit 38. In this state, the inrush current limiting resistor short open switch is always open.

The ON signal 35 short-circuits the power ON / OFF switch of the television receiver and activates the time constant signal generator 30.

The time constant signal generator 30 outputs a short-open switch control signal 34 after a certain period of time to short-circuit both ends of the inrush current limiting resistor.

After the short-open control signal 34 is issued, when the status signal 1 is not detected, the television off signal generator 31 issues the off signal 32.

With this configuration, the power of the television receiver cannot be turned on when both ends of the rush current limiting resistor are short-circuited, and the rush current is supplied when a constant current is flowing to the television receiver. When both ends of the current limiting resistor remain open, the television receiver can be turned off.

FIG. 4 shows an example of the configuration for displaying the off signal 32 shown in FIG. 3 when the television receiver is turned off.

In FIG. 4, 39 is the television off signal of 32 in FIG. 3, 40 is an LED, and 41 is a control transistor.

When the steady current continues to flow through the inrush current limiting resistor, the television receiver off signal 32 drives the transistor 41 to turn on the LED 40 and display the occurrence of the abnormal situation. At this time, for the LED 40, for example, a power-on LED may be used to change the current value to be passed to change the emission color and display the occurrence of the abnormality with the same LED.

[0032]

As described above, the present invention detects the short-open state at both ends of the inrush current limiting resistor of the RCL circuit of the television receiver, and only when both ends of the inrush current limiting resistor are open. When the power of the television receiver can be turned on, and when both ends of the inrush current limiting resistor in the steady state are not short-circuited, the power of the television receiver is turned off and the content is displayed. When the power is turned on, the inrush current is always attenuated by the inrush current limiting resistor, and during steady operation, the inrush current limiting resistor is always short-circuited.In other states, the power cannot be turned on. It is possible to realize an excellent RCL circuit that can always display the contents when the current constantly flows in the device.

[Brief description of drawings]

FIG. 1 is a block diagram of a circuit for detecting a short open state at both ends of an inrush current limiting resistor according to an embodiment of the present invention.

FIG. 2 is a block diagram of a conventional detection circuit.

FIG. 3 is a block diagram of a power-off circuit according to an embodiment of the present invention.

FIG. 4 is a display circuit diagram when an abnormality occurs in one embodiment of the present invention.

[Explanation of symbols]

1 AC plug 2 Inrush current limiting resistor 3 Inrush current limiting resistor Short-circuited open switch on both ends 4 AC voltage rectifying diode block 5 Television receiver power on / off switch 6 Smoothing capacitor 7 Inrush current path when power is turned on 8 Standby power transformer 9 Standby circuit 10 Inrush current limiting resistor both ends short open switch control signal 11 Television receiver power on / off switch control signal 12 Television receiver power on / off signal 13 Standby circuit operating status signal 14 Television receiver power on / off signal generation circuit 15 AC plug 16 Inrush Current limiting resistor 17 Inrush current limiting resistor Short open switch on both ends 18 Television receiver power on / off switch 19 AC voltage rectifying diode block 20 Standby power transformer 1 21 Standby power transformer 2 22 Smoothing capacitor 23 Standby circuit 24 Television receiver power on / off signal generation circuit 25 Inrush current limiting resistor both ends short open switch control signal 26 Television receiver power on / off switch control signal 27 Standby circuit operation by standby power transformer 2 Status signal 2 28 Status display circuit of RCL circuit 29 Standby circuit operation status signal 1 by the standby power transformer 1 30 Time constant signal generation section 31 From time constant signal and standby circuit operation status signal 1 Television receiver off signal generation section 32 Television John receiver off signal 33 Standby circuit operating status signal 1 34 Inrush current limiting resistor both ends short open switch control signal 35 Television receiver power on signal 36 Standby circuit operating status signal No. 2 37 Television receiver on signal 38 Standby circuit operation state signal 2 and television receiver on signal Television receiver on signal generator 39 Television receiver off signal 40 LED 41 Transistor

Claims (4)

[Claims] 1. A television receiver having means for short-opening both ends of a rush current limiting resistor when the power is turned on, the television receiver having means for detecting a short-open state. Current limiting circuit. 2. The inrush current limiting circuit for a television receiver according to claim 1, wherein the power of the television receiver cannot be turned on in the short-circuited state. 3. A means for turning off the power source of the television receiver when the television receiver is constantly on and both ends of the inrush current limiting resistor are left open. An inrush current limiting circuit for a television receiver according to items 1 and 2. 4. A means for displaying that both ends of the inrush current limiting resistor remain open when the television receiver is constantly on and both ends of the inrush current limiting resistor remain open. An inrush current limiting circuit for a television receiver according to claim 1, 2 or 3, characterized in that it has.