JPS6277825A - Backup power source - 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 [Field of the Invention] The present invention relates to a backup power supply device that normally supplies power from a power supply circuit to operate a control circuit, and switches to a battery for backup during a power outage.

[Summary of the invention]

The backup power supply device according to the present invention switches the power supply to the control circuit to the battery during a power outage, provides hysteresis to battery voltage level detection, lowers the reference level at the start of backup, and lowers the terminal voltage during the power outage. This is a backup power supply device that can be controlled without repeatedly operating and stopping operations at the end of backup by increasing the reference level when the voltage gradually decreases to below the reference level.

[Prior art and its problems]

For example, as shown in FIG. 4, a backup power supply device for a conventional control device supplies commercial AC power to a power supply circuit 1, converts it into a predetermined DC voltage, and supplies it to a control circuit 2, and also supplies the power supply voltage to a backup power supply circuit 1. 3 to monitor the power supply voltage, and switch to the backup amplifier power supply in the event of a power outage.

The backup power supply circuit 3 has a booster circuit 4 and a level detection circuit 5 connected to the output terminal of the power supply circuit 1, and while power is being supplied, the booster circuit 4 boosts the power supply voltage and supplies it to the bassoqua 7. In addition to float-charging the battery 6 of
, the relay X is operated via the transistor 7, and backup power is supplied from the battery 6 to the control circuit 2 via the relay contact Xc. The control circuit 2 includes a level detection circuit 8, which identifies the voltage level of the applied power supply and performs operations or stops operations to retain stored contents.

However, according to such a conventional bank amplifier power supply device, backup is provided by the battery 6 in the event of a power outage, but if the terminal voltage decreases after a predetermined period of time, the level in the control device 2 Since the detection level of the detection circuit 8 decreases, the operation is stopped. By doing so, the load on the battery 6 becomes lighter, so that the terminal voltage of the battery 6 increases again. At this time, if the threshold level of the level detection circuit 8 in the control circuit 2 is exceeded, the operation of the control circuit 2 is started again. As described above, there is a problem in that an intermittent phenomenon occurs in which the operation starts even after the battery 6 is discharged and then immediately stops due to a drop in voltage.

[Purpose of the invention]

The present invention has been made in view of the problems of the conventional backup power supply device, and includes a bank in which the control circuit can stop the operation after the discharge of the backup power supply without intermittent operation. Aims to provide up power supply equipment.

[Structure and effects of the invention]

The present invention is a bank amplifier power supply device that switches the power output from a power supply circuit to a backup power supply to supply power to a control circuit when the power supply is cut off. A power cutoff detection means for giving a cutoff signal, a battery that is charged when power is being supplied to the control circuit from the power supply circuit and supplies power to the control circuit in the event of a power outage, and a power supply voltage of the power supply circuit and an initial terminal voltage of the battery. a level detection means for detecting the voltage level supplied to the control circuit by switching between a first reference voltage level set during the period and a second reference voltage level that determines the usage limit of the battery; An operation control signal that operates based on the logical sum of a signal indicating power supply supplied from the power cutoff detection means and the output of the level detection means while voltage is being supplied, and whose operation signal is an operation control signal given to the control circuit. The reference level of the level detection means is set to the second reference voltage level based on the power cutoff signal from the output means and the power cutoff detection means, and the reference level is set to the first reference level by detecting a drop in the terminal voltage of the battery by the level detection means. and switching means for setting the voltage level, and when the terminal voltage of the battery decreases during backup and becomes below the second reference voltage level, the operation control signal to be applied to the control circuit is used as the operation stop signal. It is something.

According to the present invention having such characteristics, in the event of a power outage, voltage is automatically supplied from the battery to the control circuit to provide backup. At this time, the reference voltage of the level detection means is switched to a second reference voltage level that determines the usage limit of the battery. After a predetermined period of time, if the terminal voltage of the battery decreases to below the second reference voltage level, an operation stop signal is given to the control circuit to set the reference level of the level detection means to the power supply voltage obtained from the original power supply circuit. Switching to a higher first reference voltage level. Even if the operation of the control circuit is stopped, the terminal voltage of the battery does not rise above the first reference level, and the operation does not start again.

Therefore, according to the present invention, it is possible to provide a backup power supply device that can perform bank amplification of the control circuit for a predetermined period of time without fear of intermittent operation after the battery voltage drops.

[Explanation of Examples]

FIG. 1 is a block diagram showing an embodiment of a backup power supply device according to the present invention. In this diagram, commercial AC power supply 1
0 is given to the power supply circuit 11.

The power supply circuit 11 converts alternating current power into direct current of a predetermined voltage, and has therein a power interruption detection circuit 12 for detecting a power outage of the commercial alternating current power supply 10. Then, the power cut-off detection circuit 12 supplies the AC cut-off signal, which goes to the "off" level, to the terminal of the switching circuit 13 at the time of a power outage. Switching circuit 1
Reference numeral 3 denotes a switching circuit for switching between a DC power supply from the power supply circuit 11 during power supply and a battery backup power supply during a power outage. It is connected.

The switching circuit 13 has a level detection circuit 16 that determines the level of the terminal voltage of the power supply circuit 11 and the voltage of the backup power supply, and its reference level is switched by the switching circuit 17. Further, the outputs of the level detection circuit 16 and the power cutoff detection circuit 12 are applied to an operation control signal output circuit 18 and then applied to the control circuit 15 as an operation control signal.

In the backup power supply circuit 14, a booster circuit 19 is connected to the terminal d to which the power source of the power supply circuit 10 is applied via the diode D1, as in the conventional example described above, and charges a rechargeable secondary battery 20 via a resistor. ing.

Further, a switching transistor 21 and a relay X are connected to the output terminal of the booster circuit 19, and an AC cutoff signal from the power cutoff detection circuit 12 is applied to the base terminal of the transistor 21 via a terminal e and a terminal of the switching circuit 13. ing. The backup power supply circuit 14 switches the battery 20 from the charging state based on the AC cutoff signal applied via the switching circuit 13 and provides a backup power output to the control circuit 15 via the switching circuit 13. The control circuit 15 operates or stops its operation based on an operation control signal given from the output terminal i of the operation control signal output circuit 18.

Next, the detailed configuration of the switching circuit 13 will be explained with reference to FIG. The switching circuit 13 applies the DC voltage from the power supply circuit 11 applied to the terminal a to the backup power supply circuit 14 from the terminal d via the diode DI, and also applies it to the control circuit 15 from the terminal. A Zener diode ZDI is connected to the diode DI as shown in FIG. 2, and a transistor TRI and a resistor R2 are connected between the ground terminals via a resistor R1. Resistors R3 and R4 are connected to the transistor TRI as collector resistances, and a Zener diode ZD2 and a transistor T are connected between the emitter and the ground terminal.
The collector and emitter of R2 are connected. The transistor TR2 has a resistor R5 connected to it as a collector resistor, and its emitter is grounded. Transistor 1゛R3 is PN
It is a P-type transistor, and its base end is connected between resistors R3 and R4, and its emitter is connected to the cathode end of diode DI. Resistors R6 and R7 are connected to the transistor TR3 as collector resistances, and the midpoint thereof is applied to the base end of the transistor TR2. transistor T
RI to TR3 and Zener diodes ZDI to ZD2 constitute a level detection circuit I6 that detects the voltage level of the power supply circuit 11 and the backup power supply. Level detection circuit 1
6 is the first group 4! consisting of the total Zener voltage of the Zener diodes ZDI, ZD2! Voltage and Zener diode ZD
The input level is detected by switching a second reference voltage consisting of a Zener voltage of 1.

A switching transistor TR for switching the reference level of the level detection circuit 16 is connected between the resistor R6 and the ground terminal.
4 is connected. AC at the base of transistor TR4
Terminal twist diode D2, which is the input terminal for the disconnection signal. A series connection body of Zener diode ZD3 and resistor R8 is connected and grounded via resistor R9. Also resistance R6,
R8 each has a diode D3. Resistor R10 via D4
A voltage dividing circuit of R11 is connected, and its midpoint is connected to the base of transistor TR5. Resistors R12 and R13 are connected to the collector end of the transistor TR5. The base of a PNP transistor TR6 is connected between the common connection terminals of the resistors R12 and R13, and its collector is grounded via a resistor R14. Diode D3. D4 and transistors TR5 and TR6 constitute an operation control signal output circuit 18 which supplies an operation control signal to the control circuit 15 to determine whether to operate or stop the operation, and the operation control signal is supplied to the control circuit 15 from the terminal i.

(Operation of this embodiment) Next, the operation of this embodiment will be explained with reference to the waveform diagram in FIG. First, when the power of this device is turned on at time L1, an AC voltage is applied to the power supply circuit 1 as shown in FIG. 3(a).
1 is given. Then, as shown in FIG. 3(b), it is converted into a DC voltage and applied to the switching circuit 13 from the terminal a, and simultaneously applied to the backup power supply circuit 14 and the control circuit 15 through the terminals d and 1, respectively. . Also, at this time, the output of the power cutoff detection circuit 12 of the power supply circuit 11 is "H".
This level is applied to the switching circuit 13 through the terminal, and also applied to the backup power supply circuit 14 via the terminal e. Therefore, the backup power supply circuit 14 operates to charge the battery 20 by boosting the power supply input from the terminal d. At this time, the A and C disconnection signals are simultaneously connected to the diode D2.
Zener diode ZD3 and diode D4. Resistance RI
Since the base voltage is applied to the transistor TR5, the transistor TR5 and the transistor TR6
is in the on state and provides an "H" level operation control signal to the control circuit 15 from the terminal i. Therefore, the control circuit 15
performs predetermined operations based on power input from the terminal.

At this time, voltage is also supplied to the base of the switching transistor TR4 due to the voltage drop across the resistor R9, so the transistor TR4 is in the on state, and the base voltage of the transistor TR2 decreases, so the transistor TR
2 is off. Therefore, since a voltage is supplied to the Zener diode ZD,2 via the resistor R5, the emitter of the transistor TR1 has a potential equal to the Zener voltage v zoz of the Zener diode ZD2. Here, if the voltage supplied from the power supply circuit 11 is R9, and the terminal voltage of the backup power supply circuit 14 when charging of the battery 20 is completed is E2c, then the first reference voltage of the level detection circuit 16 is Vrer.
+ (#Vzo+ + Vzoz) is the power supply circuit 11
The voltage E of Zener die becomes larger, t--1
'ZD1. Select the Zener voltage of ZD2 (E I <
V raft V2Dl + VZDZ). In this way, the transistors TRI and TR3 of the level detection circuit 12 are turned off, and their output becomes the "L" level.

Now, assuming that a power outage occurs at time L2, the AC disconnection signal applied from the power supply circuit 11 through the terminal is "L".
level. Therefore, the transistors TR5 and TR6 of the operation control signal output circuit 18 are turned off, and the operation stop signal of the "L" level is output to the control circuit 15 as shown in FIG.
given to. Since the AC disconnection signal is also given to the backup power supply circuit 14 from the terminal e, the transistor 21 becomes conductive and the relay X is driven, and the terminal voltage of the battery 20 is transferred from the terminal g to the switching circuit 13 via the normally open contact Given. Therefore, as shown in FIG.
A power supply voltage is applied to 5 to provide backup. Immediately after backup, since the battery 20 is charged, its terminal voltage E2c is at the first reference voltage level Vrarl.
(= V2D+ + V2112) or more. Here, when the AC disconnection signal becomes "L" level, the switching transistor TR4 is turned off, and the transistor TR2 is turned on, thereby lowering the base voltage of the transistor TRI. Therefore, the reference level of the level detection circuit 16 is the second reference voltage level V-erz (!=iVzo
+).

Then, by supplying voltage from the battery 20, the transistor TRI is turned on, and at the same time, the transistor TR3 is also turned on. Now, due to the conduction of the transistor TR3, the transistors TR5 and TR6 of the operation control signal output circuit 18 are driven via the diode D3, and the third
As shown in Figure ([1], the operation control signal is turned on again at time t3.
Therefore, the control circuit 15 becomes operational again, and the terminal voltage of the battery 20 in the backup power supply circuit 14 reaches the second reference voltage level V rarz, that is, the voltage that becomes almost equal to the Zener voltage V2DI of the Zener diode ZD1. The operation continues until the point shown in Figure 3 (dl, (
As shown in e), the terminal voltage Etd of the battery 20 at time t4
When becomes less than the second reference voltage V r ,, f 2 , the transistor TRI is turned off and the transistor TR3 is also turned off.Based on this, the transistors TR5 and TR6 are also turned off at the same time, and the operation is performed as shown in FIG. 3 (fl). The control signal becomes "L" level and the control circuit 15 stops operating.This reduces the load on the battery 20, so its terminal voltage increases.However, at this time, the voltage between the emitter and collector of the transistor TR3 increases. Since the voltage drop is large and transistor TR2 is turned off, transistor TR
The emitter voltage of I is raised by 2 degrees of Zener voltage, and the reference voltage of the level detection circuit 16 is at the first reference voltage level V4 degrees. Therefore, again the transistor T
In order for RI to turn on, the terminal voltage E2 of the battery 20 must be
ga■r! . It is necessary to exceed. Therefore, when the voltage increases due to a reduction in the load on the battery 20, the transistor TRI is turned on and the control circuit 15 is not operated again.

In this way, if the capacity of the battery decreases and its terminal voltage decreases, the load is reduced, but due to the hysteresis characteristic that the reference voltage of the level detection circuit in the switching circuit increases,
The control circuit does not operate again, and the operation of the control circuit can be stopped as is.

When the power outage condition is resolved, the AC cutoff signal given by the power supply circuit becomes "H" level, so the above-described operation is repeated again, and an operation signal is given from the operation control signal output circuit, making it possible to restart the operation. Become.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the overall configuration of a puncture amplifier power supply according to an embodiment of the present invention, FIG. 2 is a circuit diagram showing the configuration of a switching circuit of a backup power supply according to this embodiment, and FIG. FIG. 4 is a waveform diagram showing waveforms of each part of the embodiment. FIG. 4 is a block diagram showing an example of a conventional backup power supply device. LL------Power supply circuit 12------Power cutoff detection circuit 13------Switching circuit 14------
-Pack amplifier power supply circuit 15--Control circuit 16--Level detection circuit 17--
---Switching circuit 18---Operation control signal output circuit 2 ゛-゛°゛Battery 3rd figure t3t'4

Claims (2)

[Claims] (1) A backup power supply device that supplies power to a control circuit by switching the power output from the power supply circuit to a backup power supply when the power supply is cut off, the backup power supply device supplying power to the control circuit by switching the power output from the power supply circuit to the backup power supply when the power supply supply to the power supply circuit that supplies DC voltage to the control circuit is stopped. a power cutoff detection means for giving a cutoff signal; a battery that is charged when power is being supplied to the control circuit from the power supply circuit and supplies power to the control circuit in the event of a power outage; Level detection means for detecting a voltage level supplied to the control circuit by switching between a first reference voltage level set between a terminal voltage and a second reference voltage level that determines a usage limit of the battery; , an operation control signal that operates based on the logical sum of a signal indicating power supply provided by the power cutoff detection means and the output of the level detection means while DC voltage is being supplied from the power supply circuit, and is applied to the control circuit; an operation control signal output means for outputting an operation signal, and setting the reference level of the level detection means to a second reference voltage level based on the power cutoff signal from the power cutoff detection means; switching means for setting a reference level to a first reference voltage level by detecting a drop in voltage; A backup power supply device characterized in that an operation control signal is an operation stop signal. (2) The battery is a secondary battery that is charged when power is supplied to the control circuit from the power supply circuit, and the first reference voltage level of the level detection means is the secondary battery at the time of charging. 2. The backup power supply device according to claim 1, wherein the level of the terminal voltage is lower than that of the terminal voltage.