JPS60152225A - Protecting 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 invention] The present invention relates to improvements in power supply protection circuits.

[Prior art]

Conventionally, when protecting the power supply of a wireless device, a switch section is generally installed at the power input of the wireless device, and a detection port is used to detect overcurrent that flows when the wireless device becomes overloaded for some reason. A method of protection has been adopted in which a circuit breaker has the function of automatically opening (OFF) the circuit breaker.

An example of this type of conventional protection circuit is 8! ``S1 To explain it as shown in Figure 1, in the figure, 1a and 1b are input terminals to which power input is applied, and 2 is a circuit breaker that has the function of turning off the switch section by flowing current. The coil 2b has the function of turning off the switch 2a when a current exceeding the set current value flows through the switch 2&, and the coil 2b has the function of forcing the current to flow and turning off the switch 2a when the power supply circuit becomes abnormal. 2c, H7/J is constructed. 3 is an input smoothing circuit, 4 is a switchable circuit that receives the output of this input smoothing circuit 3, 5 is an output smoothing circuit connected to the output side of this switching circuit 4, 6 and 7 are overcurrent detection circuits and overvoltage detection circuits that operate in response to transient faults. 8
10 is an amplifier circuit that receives the output of the overcurrent detection circuit 6 and the output of the reference voltage generation circuit 9 as input, and amplifies the difference voltage between the detected output voltage and the reference voltage from the reference voltage generation circuit 9; This is a pulse width modulation circuit that converts the voltage difference between the two into changes in pulse width, and is configured to change the on/off ratio of the switching circuit 4 based on the output of this pulse width modulation circuit 10. 11 is a drive circuit that inputs the output of the overcurrent detection circuit 6 and the output of the overvoltage detection circuit 7 and drives the circuit breaker 2 to turn off the circuit breaker 2; 12a and 12b send the output voltage to the outside; It is an output terminal.

Then, a switching circuit 4. Amplification circuit 8. Reference voltage generation circuit 9. The pulse width modulation circuit 10 forms a loop as a switching regulator.

That is, as mentioned above, if a current exceeding the set value flows transiently for some reason in the coil 2b of the circuit breaker 2, or if a current flows transiently in the overcurrent detection circuit 6 although it is not abnormal. However, the Zerkit Breaker 2 was constantly disconnecting the wireless line. In addition, switching regulators generally have a wide operating input voltage range, so when the above loop occurs, the output voltage sent from the output terminals 12a and 12b will be higher than the set voltage, so an overvoltage detection circuit T is added. When the voltage becomes abnormal, the circuit breaker 2 is turned off via the drive circuit 11. However, in this case as well, the circuit breaker 2 is disconnected even when the pressure increases transiently, leading to disconnection of the wireless line.

However, in simple circuits such as , even if the overload condition is not permanent and the failure is temporary, if the overcurrent exceeds the set value, the circuit breaker will be activated.
2 is turned off mechanically, so normally, like a wireless device,
If the system is installed at an unmanned relay station where there is no maintenance personnel, the maintenance personnel will need to go to the unmanned relay station to simply turn on the circuit breaker again, rather than due to a malfunction. in this case,
During the time it takes maintenance personnel to get to the wireless relay station, the wireless equipment is not working, so the line is disconnected, resulting in poor communication service conditions and the disadvantage that emergency communications may not be possible. Ta.

[Object and structure of the invention]

In view of the above points, the present invention has been made to solve such problems and eliminate such drawbacks.The purpose of the present invention is to prevent permanent damage to wireless lines with a simple circuit configuration, and to The purpose is to provide the above path.

In order to achieve such an object, the present invention provides a first switch element connected between the other end of the circuit breaker and the switching regulator, and a first switch element connected in parallel between the gate and source of the first switch element. a first drive element that drives the first switch element; a resistor that is connected to the first drive element and applies a bias; and a second switch whose source and drain are connected in parallel with the first drive element. and a second switching element connected in parallel between the gate and source of the second switching element and driving the second switching element.
a drive element, and a first drive circuit that receives output signals from an overcurrent detection circuit and an overvoltage detection circuit and operates the second drive element; When the circuit is operated, a current flows through the coil of the circuit breaker, and the circuit breaker is turned off to prevent the wireless line from being disconnected. The first drive circuit operates the element, the counter circuit counts the number of operations of the first drive circuit, and the second drive circuit operates based on the output signal of the counter circuit to flow a current to the coil of the circuit breaker. 2 drive circuits for the power supply or the load of the power supply in case of constant faults.
The above circuit breaker is installed to prevent further failures.
It is designed so that it can be cut off.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 2 is a block diagram showing an embodiment of the protection circuit according to the present invention.

In Fig. 2, the same reference numerals as in Fig. 1 indicate corresponding parts, and 2 is a circuit breaker, one end of which is connected to the load side of switch 2a, which forces current to flow and turns off switch 2a. The coil 2d is composed of the following.

Reference numeral 13 denotes a first switch element inserted between the zerkid breaker 2 and the input smoothing circuit 3 to turn it on and off, and 14 a first switch connected in parallel between the source and gate of the first switch element 13. A first drive element 15 drives the element 13; A resistor 16 biases the II element 14, a second switch element 16 turns on and off the first driving element 14, and a second switch 1T is connected in parallel between the source and gate of the second switch 16. This is the second single force element that turns the inch 16 on and off.

18 is a first drive circuit which receives the output of the overcurrent detection circuit 6 and the output of the overvoltage detection circuit 7 and applies a bias to the ml dynamic element 17; A counter circuit 20 counts the number of times the circuit breaker 17 is driven and sends out an output when a preset number of times is reached, and a second drive circuit 20 operates based on the output of the counter circuit 19 to turn off the circuit breaker 2. It is.

Next, the operation of the embodiment shown in FIG. 2 will be explained.

First, turn on circuit breaker 2 to put the power supply (switch regulator) into operation.

By turning on, a voltage is applied to the first drive element 14 and the bias resistor 15, and the first switch 13 is turned on by the first drive element 14. When the first switch 13 is turned on, the switching circuit 4. Amplification circuit 8. A low-switching regulator configured as a loop of a reference voltage generation circuit 9 and a pulse width modulation circuit 10 operates, and a stabilized output voltage is sent out from output terminals 12a and 12b.

Next, the overcurrent detection circuit 6 or the overvoltage detection circuit 7 operates due to some temporary cause, and the first drive circuit 18 receives its output signal and drives the second drive element 17, and the second switch element 17 is activated. 16 transitions to the off state. When the second switching element 16 is turned on, the first driving element 14 is turned off, and as a result, the first switching element 13 is transferred to the off state, so that the input voltage of the switching regulator is interrupted. Therefore, output terminals 12a and 12b
The voltage sent to the outside is cut off.

However, when the above-mentioned general cause disappears, the second switching element 16 is turned on again, and accordingly, the first switching element 13 is turned on, and the switching regulator starts operating. , output terminal 12
The output voltage is sent to the outside from a and 12b.

Next, if a failure such as a failure or a short circuit in the load occurs in the switching regulator described above, as described above, the overvoltage detection circuit 7 is not turned ON, and the overcurrent detection circuit 6 is turned ON→Ni
ON of O2 dynamic circuit 1B → ON-+ of N2 O2 dynamic element 17
ON of the second switch element 16 → OFF of the NiO2 dynamic element 14 → OFF of the first switch element 13 → OFF of the switching regulator → OFF of the over-positive first current detection circuit 6 or over-voltage detection circuit 7 → 1st drive circuit 1B OFF
→ OF'F- of second driving element 17 + 0FF- of second switching element 16 + ON of first driving element 14 → NiO
A fourteenth loop is formed in which the two-switch element 13 is turned on and the switching regulator starts operating.

The number of operations in the loop is counted by the counter circuit 19, and when the counted value reaches a preset number of times, a current is applied to the coil 2d of the circuit breaker 2 via the second drive circuit 20. Flow and break Zerkit Breaker 2.

In this way, in the case of a temporary cause, instead of turning off the circuit breaker 2 and causing a permanent failure of the wireless line, the first switch element 13 is turned off to temporarily stop the operation of the switching regulator, and the wireless line is stopped. Permanent line failure can be prevented. In addition, if the temporary cause repeatedly occurs, or if the failure of the switching regulator itself or the failure of the external load is a regular failure, it is determined that the failure is a permanent failure and the first drive circuit 18 is The number of operations is counted by the counter circuit 19 and the circuit breaker 2 is turned off via the second drive circuit 20, thereby making it possible to prevent a secondary failure from the above-mentioned failure.

In the embodiment shown in FIG. 2, since the input voltage is a negative voltage, the first and second switch elements 13.1
Although the case where an N-channel FET is used in 6 is explained as an example, the present invention is not limited to this.If the input voltage is a positive voltage, using a P-channel FET provides the same advantages as described above.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, an overcurrent detection circuit or an overvoltage detection circuit is activated by a transient fault, and a circuit breaker is activated without using complicated means.
With a simple circuit configuration that prevents the wireless line from being disconnected, and also prevents secondary failures of the Denbuchi device or the load of the Denbuchi device in the case of regular failures,
In the case of a temporary cause, instead of turning off the circuit breaker and causing a permanent failure of the wireless line, the first switch element is turned off to temporarily stop the operation of the switching regulator to prevent a permanent failure of the wireless line. In addition, if the temporary cause recurs repeatedly, or if the failure of the switching regulator itself or the external load is a regular failure, it is determined to be a permanent failure and the number of operations of the drive circuit is reduced. By counting and turning off the circuit breaker, it is possible to prevent secondary failures due to the above-mentioned failures, so the practical effect is extremely large.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an example of a protection circuit in a conventional power supply device, and FIG. 2 is a block diagram showing an example of a protection circuit according to the present invention (11 diagrams). -1a, jb...Power input Terminal, 2...Fist zer kit breaker, 21L...Fist switch, 2d...
Pot coil, 4... fist/switching circuit, 6... overcurrent detection circuit, T... overvoltage detection circuit, 8...
Amplifier circuit, 9...Reference voltage generation circuit, 10...
Pulse width modulation circuit, 12a. 12b...Output terminal, 13...First switch element, 14...First drive element, 15.II+1.
Resistor, 16@-... Second switch element, 17...
Second drive element, 18...first drive circuit, 19.
轡・Fist counter circuit, 20・Life・Second drive circuit.

Claims (2)

[Claims] (1) A switching regulator that is equipped with an overcurrent detection circuit and an overvoltage detection circuit has a switch section and a coil that turns off the switch section by flowing current, and one end of the switching regulator is connected to a power input terminal. A circuit breaker that connects the switch section and forms the other end, an amplifier circuit that amplifies the difference voltage between the output voltage from the overvoltage detection circuit and the reference voltage, and a pulse width change of the difference voltage between the amplifier circuit and the overvoltage detection circuit. and a pulse width modulation circuit that converts the output voltage into a pulse width modulation circuit to change the on/off ratio of the switching circuit of the switching regulator, and transmits the output voltage to the outside through an output terminal connected to the overvoltage detection circuit. a first switching element connected between the other end of the breaker and the switching regulator;
a first drive element connected in parallel between the gate and source of the first switch element to drive the first switch element; a resistor connected to the first drive element to apply a bias; a second switch element whose source and drain are connected in parallel to the drive element; a second drive element which is connected in parallel between the gate and source of the second switch element and drives the second switch element; a first drive circuit that receives output signals from the overcurrent detection circuit and the overvoltage detection circuit and operates the second drive element; 1. A protection circuit according to claim 1, wherein a current flows through the coil of the Zerkit breaker and the Zerkit breaker is turned off, thereby preventing the radio line from being disconnected. (2) A switching regulator equipped with an overcurrent detection circuit and an overvoltage detection circuit has a switch section and a coil that turns off the switch section by passing current, and one end is connected to the power source/blade end. A circuit breaker connecting the coil and the switch section and forming the other end, a J-type circuit that amplifies the voltage difference between the output voltage from the overvoltage detection circuit and the reference voltage, and a voltage difference from this amplification circuit. and a Norms width modulation circuit that converts the voltage into a change in Norms width to change the on/off ratio of the switching circuit of the switching regulator. In the power supply device, a first switching element connected between the other end of the circuit breaker and the switching regulator is connected in parallel between the gate and source of the first switching element. a first driving element that drives the switch element; a resistor that is connected to the first driving element and provides a source;
The second one with the drain connected. and a second switch element of
a second drive element that is connected in parallel between the gate and source of the switch element and drives the second switch element; and a second drive element that receives output signals from the overcurrent detection circuit and the overvoltage detection circuit and drives the second drive element. a first drive circuit to operate;
A counter circuit that counts the number of operations of the first drive circuit, and a second drive circuit that operates in reverse based on the output signal of this counter circuit to flow a current to the coil of the circuit breaker. On the other hand, a protection circuit characterized in that it is capable of preventing secondary 1i#@ of the power supply device or the load of the power supply device.