JPH01122328A - Cooling device - Google Patents

Abstract

PURPOSE:To prevent temperature rise in apparatuses after the output of a main power source is interrupted, by a method wherein a cooler is operated by a first power source while the cooler is operated by a second power source for a predetermined period of time after the power supply of the first power source is interrupted. CONSTITUTION:The voltage of 2V is impressed on the plus input terminal B of a voltage comparator 5 and the voltage of 6V is impressed on the minus input terminal C of the same when the power supply of a main power source 1 is interrupted, therefore, the output terminal D of the voltage comparator 5 becomes low potential. A transistor Q1 is brought into conducted state through a resistor R6 and a power is supplied from a stand-by power source 2 to a cooler 3 whereby the operation of the cooler 3 is started. The potential of the minus input terminal C of the voltage comparator 5 is reduced gradually by a time constant discharging circuit, consisting of a capacitor C1 and resistors R1, R2, after the supply of the main power source is interrupted and a time has elapsed. When the potential has dropped to less than 2V at last, the potential of the output terminal D of the voltage comparator 5 is converted into a high potential. According to this method, the transistor is biased reversely and is brought into non-conductive whereby the operation of the cooler 3 is stopped. The stop condition is continued until the main power source 1 is operated again.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a cooling device for equipment, and particularly to a device for preventing temperature rise inside a machine by using a second power source after the first power source is stopped.

[Prior Art] FIG. 2 is a block diagram showing an example of the configuration of a conventional cooling device. In the same figure, 1 is a first power source (hereinafter referred to as the main power source) that primarily supplies power to the device when the device is in operation, and 2 is a power source that can supply power to the device for backup purposes even when the device is stopped. 2 is a power source (hereinafter referred to as a standby power source), 3 is a cooler for the equipment, and 4 is an equipment load to which power is supplied.

The equipment load 4 receives its required power mainly from the main power supply 1 and partly from the standby power supply 2, and the cooler 3 receives the required power only from the main power supply 1. Therefore, in this cooling device, the inside of the device is cooled only when the main power supply 1 is operating.

FIG. 3 is a block diagram showing another example of the configuration of a conventional cooling device. Each unit in this figure is the same as in FIG. 1 and is indicated by the same reference numeral.

In the figure, the cooler 3 is supplied with the necessary power only from the standby power supply 2. Therefore, this cooling device performs cooling even when the equipment is stopped.

As explained above, in the prior art, there are only two methods: to operate the cooler of the equipment in synchronization with the activation or stoppage of the equipment, or to operate the cooler constantly regardless of the operation of the equipment.

[Problems to be Solved by the Invention] However, in the conventional device having the configuration shown in FIG. 2, when the main power supply 1 stops operating, the cooler 3 also stops operating immediately. There was a problem in that the temperature of the capacitor temporarily rose, causing parts such as electrolytic capacitors to deteriorate.

Further, in the apparatus having the configuration shown in FIG. 3, since the cooler 3 is constantly operating, there is a problem that the life of the cooler (for example, a fan) is significantly shortened and the power consumption is also large.

The present invention is intended to solve the above-mentioned problems, and aims to prevent the temperature inside the device from rising after the output of the main power supply is stopped without shortening the life of the cooler.

[Means for Solving the Problems] The present invention provides a cooling device for various electronic devices having two power sources, a first power source and a second power source, in which the cooler is connected to the first power source when the first power source is activated. The cooler is operated by a power source, and after the first power source is stopped, the cooler is operated by a second power source for a certain period of time.

[Function] In the present invention, the cooler of the equipment is normally operated by the first power source, and after the same power source is stopped, it is switched to the second power source and is operated only for a certain period of time. It also has a power supply time control function.

[Embodiment] FIG. 1 is a circuit diagram according to an embodiment of the present invention. In this figure, the same parts as in FIGS. 2 and 3 are designated by the same reference numerals. Further, FIG. 4 shows a voltage waveform diagram for explaining the operation of FIG. 1.

Description will be made below based on FIGS. 1 and 4.

In Figure 1, D1-D4 are diodes, R1-R7
is a resistor, C1 is a capacitor, Ql is a transistor, 5
is a voltage comparator, and these parts make up the cooler control circuit 6.
Configure.

Also, (A) is the main power output terminal, (B) is the voltage comparator 5
(C) is the negative input terminal of the comparator 5, (D) is the output terminal of the comparator 5, (E) is the input terminal of the cooler 3, and the voltage waveform of each terminal is as follows. 4 (A) to (E).

In this embodiment, the output voltage of the main power supply and standby power supply is 12V DC. Further, the resistance values of the resistors R1 and R2 are set so that the potential at point (C) becomes 6V when the main power supply 1 outputs.

The resistance values of the resistors R3, R4, and R5 are set so that the potential at point (B) is 8V when the main power supply 1 is in operation, and 2V when the main power supply 1 is stopped.

Next, the operation of each part will be explained. First, when the main power supply 1 is in operation, a voltage of 8V is applied to the positive input terminal (B) of the voltage comparator 5, and a voltage of 6V is applied to the negative input terminal (C).

Therefore, the output terminal (D) of the voltage comparator 5 is at a high potential, and the transistor Ql is reverse biased by the resistor R7 and is in a non-conducting state. The cooler 3 is operated by being supplied with power from the main power supply 1 via the diode D4.

That is, a voltage of approximately 11V, which is obtained by subtracting the forward voltage drop of the diode from 12V of the main power supply 1, is applied to the input terminal (E) of the cooler 3, and the cooler 3 is driven.

Next, when the main power supply 1 is stopped, a voltage of 2V is applied to the positive input terminal (B) of the voltage comparator 5, and its negative input terminal (C)
Since a voltage of 6V is applied to the voltage comparator 5, the output terminal (D) of the voltage comparator 5 has a low potential. As a result, the transistor Q1 is positively biased through the resistor R6 and becomes conductive, and the cooler 3 is connected to the standby power supply 2 by the transistor Q1.
Power is supplied through the power supply and it starts operating. After the main power supply 1 is stopped, the potential at the negative input terminal (C) of the voltage comparator 5 gradually decreases over time due to the time constant discharge circuit of the capacitor CI and the resistors R1 and R2, and finally reaches 2.
When the voltage becomes lower than v, the output terminal (D) of the voltage comparator 5 is inverted to a high potential. When the output terminal (D) of the voltage comparator 5 becomes a high potential, the transistor Q1 becomes non-conductive as a result of being reverse biased, and the cooler 3 stops operating.

That is, the time from when the output terminal (D) of the voltage comparator 5 becomes a low potential until it returns to a high potential again: T (T=;1.1
- (R1+R2) - Only during C1), the cooler 3 performs cooling operation by the standby power supply 2. This stopped state continues until the main power source 1 is activated again.

In the description of this embodiment, the output voltage of the main power supply and standby power supply was set to 12 V DC, but the present invention can exhibit similar effects with other output voltages. In addition, by changing the resistance value setting of the time constant discharge circuit or changing the capacitance value of the capacitor, it is possible to adjust the operation time of the cooler using the standby power supply after the main power supply is stopped, which has a practical effect. big.

[Effects of the Invention] As explained in detail above, according to the present invention, even after the first power source is stopped, the cooler of the device is continuously operated by the second power source for a certain period of time, so that the life of the cooler can be shortened. This has the effect of preventing a temperature rise inside the device after the first power supply is stopped, and has a great effect on preventing device failure and saving power consumption.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of an embodiment of the present invention, Fig. 2 is a block diagram of a conventional cooling device 1, Fig. 3 is a block diagram of a conventional cooling device 2, and Fig. 4 shows the operation of Fig. 1. It is a waveform diagram for explanation. In the figure, (1) is a main power supply, (2) is a standby power supply, (3) is a cooler, (4) is an equipment load, (5) is a voltage comparator, and (6) is a cooler control circuit.

Claims (1)

[Claims] A first power source that supplies power when the device is in operation, a second power source that supplies power even when the device is stopped, and the two power sources are selected as inputs, and the output time is and a cooler that cools the inside of the device using a power output supplied from the control circuit, and the control circuit is a circuit that supplies the first power output to the cooler in response to an operation signal of the device. and a circuit that supplies the second power output to the cooler for a certain period of time from the start of a stop signal of the equipment.