JPS6335122A - Interruption detector of electric source - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a power failure detection device used in a switching type DC stabilized power supply or the like.

[Conventional technology]

In a stabilized DC power supply, when the input is turned on and off or when there is a momentary power outage, the output drops and unstable voltage is applied to the central processing unit (CPU) of the load, causing malfunction. Therefore, a power failure detection device is required that sends a predetermined signal from the voltage side to the central processing unit (CPU) of the load when such an abnormal output occurs from the power supply.

Therefore, in conventional DC stabilized power supplies, as a power failure detection device, the DC voltage generated by the rectifier circuit and smoothing capacitor of the main power supply is supplied to the auxiliary power inverter connected in parallel to the main power inverter. It is known that the AC voltage generated by the power inverter is stepped down via an auxiliary power transformer, and the stepped down voltage is rectified again and supplied to a power outage detection circuit.

In the conventional power failure detection device configured in this way, when the input AC voltage to the main power rectifier circuit is cut off or decreased,
The voltage applied to the auxiliary power supply circuit as well as the main power supply circuit is eliminated. Therefore, no DC voltage is generated on the output side of the auxiliary power supply circuit, and the power failure detection circuit detects this and outputs a power failure detection signal to the central processing unit (CPU) of the load. Here, the detection delay time from when a power outage occurs until a detection signal is generated in the power outage detection circuit is determined by the discharging time (hereinafter referred to as holding time) of the smoothing capacitor of the main power supply, and therefore the load on the main power circuit However, when there is a heavy load, the detection delay time becomes small, and when there is no load, the detection delay time becomes large.

[Problem that the invention seeks to solve]

As mentioned above, in conventional power failure detection devices, the power failure detection delay time is determined by the capacity of the main power supply smoothing circuit.
Furthermore, there is a time difference in power failure detection depending on the presence or absence of a load on the main power circuit. Therefore, there is a drawback that stable malfunction prevention control cannot be performed on the central processing unit of the load.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a power supply power failure detection device that can generate a power failure detection signal within a predetermined set time regardless of the magnitude of the load on the main power supply circuit.

[Means for solving problems]

The power supply power failure detection device according to the present invention is configured such that an auxiliary power supply circuit is connected in parallel to the main power supply circuit, and the auxiliary power supply circuit outputs a control voltage signal of the main power supply circuit and a power failure detection signal to the power failure detection circuit. In the DC stabilized power supply, the auxiliary power circuit includes an auxiliary power transformer, a rectifier circuit, a smoothing capacitor, and an inverter are connected to the primary side of the power transformer, and a rectifier and a smoothing capacitor are connected to the secondary side of the power transformer. The capacitance of the smoothing capacitor connected to the primary side of the power transformer is set smaller than the capacitance of the smoothing capacitor connected to the primary side of the power transformer of the main power circuit.

The power failure detection device described above is configured to output an inverter control voltage to the secondary output terminal of the power transformer of the auxiliary power supply circuit via a positive direction diode and a smoothing capacitor, and also includes a negative direction diode, a smoothing capacitor, and a resistor. It can be configured to output a power outage detection signal via.

[Effect]

According to the power failure detection device according to the present invention, by separately providing a rectifier circuit and a smoothing capacitor in the auxiliary power supply circuit, it is possible to control the power failure detection time by selecting the capacity of the smoothing capacitor in the auxiliary power supply circuit. . In addition, by selecting the capacity of the smoothing capacitor in the auxiliary power circuit to be smaller than the capacity of the smoothing capacitor in the main power circuit, the hold time of the auxiliary power circuit can be set shorter than the hold time of the main power circuit, and power failure detection can be performed appropriately. Then, by holding the main power supply circuit, the inverter control voltage can be smoothly supplied.

〔Example〕

Next, embodiments of the power failure detection device according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a circuit diagram of a DC stabilized power supply showing an embodiment of the power failure detection device of the present invention. In the figure, reference numeral 10 indicates a main power rectifier circuit that rectifies the AC input voltage, and a main power inverter 14 is connected to the output side of this main power rectifier circuit 10 via a smoothing capacitor I2, and the output of this inverter 14 is The side is connected to the primary winding side of the main power transformer 16. A rectifier circuit including diodes 18 and 20 is connected to the secondary winding side of the main power transformer 16, and a smoothing reactor 22 and a smoothing capacitor 24 are connected to the output 1 of this rectifier circuit. Configure the circuit to extract the DC output voltage from both connected terminals.

On the other hand, an auxiliary power rectifier circuit 26 is connected in parallel with the main power rectifier circuit 10, and an auxiliary power inverter 30 is connected to the output side of the rectifier circuit 26 via a smoothing capacitor 28. The output side of the inverter 30 is connected to the primary winding side of the auxiliary power transformer 32. A diode 34 is connected to the secondary winding side of this auxiliary power transformer 32.
A rectifier circuit consisting of a smoothing capacitor 36 and a smoothing capacitor 36 is connected and configured to supply the voltage rectified by the rectifier circuit to a control circuit that controls the main power inverter 14.

Note that the output terminal to this control circuit is connected to the (→ side output terminal of the above-mentioned main power supply circuit via a diode 38,
The circuit is configured so that the output voltage of the main power supply circuit can also be supplied to the auxiliary power supply circuit side. Further, a diode 40 and a smoothing capacitor 42 are connected in parallel with the rectifier circuit of the auxiliary power supply circuit.
A rectifier circuit consisting of a resistor 44 and a resistor 44 is connected and configured so that the voltage rectified by the rectifier circuit is output to the power failure detection circuit.

In the DC stabilized power supply of this embodiment configured in this way, when an AC voltage is input, the input AC voltage is rectified by the main power rectifier circuit 10, and the rectified voltage is sent to the main power inverter via the smoothing capacitor 12. 14 for AC conversion. Furthermore, the AC voltage obtained by this inverter 14 is rectified by a rectifier circuit consisting of diodes 18 and 20 via a main power transformer 16, and this rectified voltage is transferred to a smoothing reactor 22 and a smoothing capacitor 24.
to generate a DC output voltage.

Also, in the auxiliary power supply circuit, the auxiliary power supply rectifier circuit 26
, the smoothing capacitor 28, and the auxiliary power inverter 30 perform the same operation as the main power circuit, and the AC voltage thus obtained is transmitted to the secondary side circuit of the auxiliary power transformer 32. 34 and the smoothing capacitor 36 and the obtained voltage is supplied to a control circuit that controls the main power inverter 14,
On the other hand, a negative voltage obtained by negative rectification by a rectifier circuit including a diode 40, a smoothing capacitor 42, and a resistor 4 is output to a power outage detection circuit.

Here, when the AC input voltage is cut off when the power input is turned off or during a power outage, the main power rectifier circuit 10 and the auxiliary power rectifier circuit 26 stop their operation, but even after that, the holding time of the smoothing capacitor 12.28 continues. Meanwhile, the main power inverter 14 and the auxiliary power inverter 30 are operated by the discharge voltages of these capacitors.

Eventually, when the holding time of the smoothing capacitor 28 has elapsed, the auxiliary power inverter 30 stops operating, and the diode 34
．． The voltage applied to 40 is no longer applied, and the negative voltage to the power failure detection circuit is no longer output. At this point, the power failure detection circuit outputs a power failure detection signal to the central processing unit of the load. Therefore, the detection delay time from when a power outage occurs to when a power outage detection signal is generated is determined by the holding time of the smoothing capacitor 28 of the auxiliary power supply circuit, and can be set to any time by selecting the capacitance.

Furthermore, if the capacity of the smoothing capacitor 28 of the auxiliary power supply circuit is selected to be smaller than the smoothing capacitor 12 of the main power supply circuit, the holding time of the auxiliary power supply circuit will be shorter than the holding time of the main power supply circuit, and even after the occurrence of a power failure detection signal, smoothing will be maintained. During the holding time of the capacitor 12, the main power inverter 14 operates and a DC voltage is output to the output terminal of the main power circuit. Therefore, during this period, the central processing unit (CP) of the load that received the power outage detection signal
U) can perform predetermined malfunction prevention control.

Note that voltage can be supplied to the control circuit of the main power inverter 14 after the auxiliary power supply circuit is stopped from the (→ side output terminal of the main power supply circuit) via the diode 38.
4゜[Effects of the Invention] As is clear from the embodiments described above, according to the present invention, the power failure detection time can be controlled by the capacity of the smoothing capacitor of the auxiliary power supply circuit, and moreover, the retention time of the auxiliary power supply circuit can be controlled. By setting the time shorter than the holding time of the main power circuit, the main power circuit can be operated to supply voltage to the load even after a power failure is detected. Therefore, when a power outage occurs, it is quickly detected and the central processing unit (CPU) of the load
), the power failure detection signal can be detected and the central processing unit of the load can be reliably controlled to prevent malfunctions, and it is possible to improve the performance of this type of power failure detection device and realize it at low cost. can.

Although the preferred embodiments of the present invention have been described above, it goes without saying that various design changes may be made without departing from the spirit of the present invention.

[Brief explanation of the drawing]

FIG. 1 is a DC stabilized power supply circuit diagram showing an embodiment of a power failure detection device according to the present invention. 10... Main power rectifier circuit 12.24.28, 36.42... Smoothing capacitor 1
4... Main power inverter 16... Main power transformer 18.20, 34, 38.40... Diode 22.
... Smoothing reactor 26 ... Auxiliary power rectifier circuit 3
0...Auxiliary power inverter

Claims (3)

[Claims] (1) Connect and arrange the auxiliary power circuit in parallel to the main power circuit,
In a DC stabilized power supply configured such that the auxiliary power supply circuit outputs a control voltage signal of the main power circuit and a power failure detection signal to the power failure detection circuit, the auxiliary power supply circuit is equipped with an auxiliary power transformer, and the primary side of the power supply transformer is A rectifier circuit, a smoothing capacitor, and an inverter are connected to the power supply transformer, a rectifier and a smoothing capacitor are connected to the secondary side of the power transformer, and the capacity of the smoothing capacitor connected to the primary side of the power transformer is set to be smaller than that of the main power supply. A power outage detection device featuring: (2) In the power failure detection device according to claim 1, the secondary output end of the power transformer of the main power circuit and the secondary output end of the power transformer of the auxiliary power circuit are connected via a rectifier. A power outage detection device for power supplies. (3) The power failure detection device according to claim 1 is configured to output an inverter control voltage to the secondary output terminal of the power transformer of the auxiliary power supply circuit via a forward diode and a smoothing capacitor. A power outage detection device for a power supply, which is configured to output a power outage detection signal via a negative direction diode, a smoothing capacitor, and a resistor.