JP2000184581A - Electronic device and power supply - Google Patents

Abstract

PROBLEM TO BE SOLVED: To take a required procedures before the operation is shut down because of irregular overheat of user. SOLUTION: An overheat protecting means 14 outputs an alarm signal SAM when a device temperature rises exceeding an alarm temperature TAM. The protecting means 14 outputs a shut-down signal SSD when the device temperature rises, at the condition where such device temperature is at the intermediate temperature between the alarm temperature TAM and shut-down temperature TSD is continued for the predetermined period, and also when the device temperature rises exceeding the shut-down temperature TSD. Meanwhile, the control means 12 controls the alarm display control and shut-down control on the basis of the alarm signal SAM and shut-down signal SSD.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic device such as a power supply device that performs an overheat protection operation when the temperature of the device becomes abnormal.

[0002]

2. Description of the Related Art In a power supply device having a heat-generating electronic component such as a transistor inside, a heat generated from the electronic component is radiated through, for example, a radiator, and the temperature inside or outside of the device or the entire temperature (device temperature). This has the effect of preventing the abnormal rise of the battery to some extent. However, depending on the usage of the power supply device and other factors, even if heat is radiated to a certain extent by the heat radiator, the internal temperature may continue to rise, resulting in abnormal internal overheating. Therefore, in such a case, the conventional power supply device is forcibly stopped (shut down) immediately before the inside of the power supply device is abnormally overheated, thereby preventing the device from being destroyed from abnormal overheating. . Of course, even in the case of a power supply device that is not provided with a heat radiator, the device is also shut down immediately upon abnormal internal overheating to prevent destruction of the device.

[0003]

However, if a power supply having the above-mentioned overheat protection function is incorporated in some system, and the power supply is shut down, it is necessary from a user's standpoint. There was a problem that the entire system was forcibly stopped without taking any measures.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an electronic device such as a power supply device so that a user can take necessary measures before an output is shut down due to abnormal overheating.

[0005]

According to the present invention, a converter for converting an input voltage to a predetermined output voltage, an overheat protection unit for outputting an overheat protection signal when the temperature of the device reaches the overheat protection temperature, A control unit for controlling the temperature to be constant and performing a heat protection control in response to the heat protection signal, wherein the overheat protection unit generates an alarm when a device temperature rises and exceeds an alarm temperature. A signal is output, a shutdown signal is output when a state at an intermediate temperature between the alarm temperature and the shutdown temperature has continued for a predetermined time, and a shutdown signal is output when the shutdown temperature has been exceeded. Alarm display control based on alarm signal, shutdown signal,
The above-mentioned problem is solved by performing the shutdown control.

[0006]

Embodiments of the present invention will be described below in detail with reference to the drawings. In this embodiment, an electronic device is described as being applied to a switching power supply. However, the present invention is not limited to this, and can be applied to other power devices, and can be applied to electronic devices other than the power device. It is something.

In summary, the switching power supply of the present embodiment includes a converter for converting an input voltage to a predetermined output voltage, and an overheat protection unit for outputting an overheat protection signal when the temperature of the device reaches the overheat protection temperature. A control unit for controlling the output voltage to be constant and performing a heating protection control in response to the heating protection signal, wherein the overheat protection unit increases the temperature of the device to exceed the alarm temperature. Outputs a shutdown signal when the state at an intermediate temperature between the alarm temperature and the shutdown temperature has continued for a predetermined time, and outputs a shutdown signal when the shutdown temperature has been exceeded. The unit is a power supply device that performs alarm display control and shutdown control based on the alarm signal and the shutdown signal. In this case, the device temperature includes not only the temperature of the heat-generating electronic components described in the embodiment described below, but also the temperature of the surroundings, the temperature of the casing, and the components constituting the inside and outside of the power supply, the components in the structure, and the like. Some temperatures include the whole temperature. The cause of the increase in the device temperature is not limited to the heat generated by the heat-generating electronic components described in the embodiment described later, but also includes the case where the temperature rises due to the influence of the temperature around the switching power supply or other causes.

Referring to FIG. 1, a switching power supply according to an embodiment of the present invention has an input rectifying and smoothing unit 2 as a basic configuration.
Converter 4, output rectifying / smoothing unit 6, output voltage detecting unit 8, comparison feedback unit 10, control unit 12
The rectifying and smoothing unit 2 rectifies and smoothes the AC input and inputs the rectified and smoothed input to the converter unit 4. The converter unit 4 converts an input into a predetermined output according to the on / off operation of the switching element and outputs the output. The output rectifying / smoothing unit 6 includes a converter unit 4
Rectifies and smoothes the output to generate an output voltage. This output voltage is detected by the output voltage detection unit 8 and supplied to the comparison feedback unit 10. Comparison feedback unit 10
Compares the output of the output voltage detection unit 8 with a reference value and gives the comparison result to the control unit 12. The control unit 12 controls the conversion operation of the converter unit 4 based on the comparison input, and controls the output voltage to be constant. Since the detailed operation of such a switching power supply is well known, a detailed description thereof will be omitted.

The heat-generating electronic components in such a switching power supply include, for example, a switching element in the converter unit 4 or a rectifying diode (not shown) in the output rectifying / smoothing unit 6. Such heat-generating electronic components are usually
It is mounted on a radiator so that the generated heat can be radiated. Then, the temperature of the heat-generating electronic component gradually or rapidly rises due to insufficient heat radiation area of the heat radiator or other factors, and the heat-generating electronic component is overheated. As a result, the switching power supply itself may be destroyed. Therefore, in the switching power supply of the present embodiment, the overheat protection temperature for protecting the heat-generating electronic components from overheating, the overheat protection temperature as a warning stage for warning the user, and the overheat protection temperature for forcibly shutting down the output. At least two steps, so that the user can take necessary measures. Therefore, the switching power supply according to the present embodiment includes an overheat protection unit 14, a timer unit 16, and a display unit 18 in addition to the above basic configuration.

The overheat protection section 14 measures the temperature (equipment temperature) of the heat-generating electronic components and the like, and when the equipment temperature rises and reaches the alarm temperature T _AM , an alarm signal S _AM is sent to the timer section 16 and the control section 12. When the temperature rises to the shutdown temperature T _SD , the shutdown signal _SSD is output to the control unit 12. The timer section 16 starts the timer operation in response to the input of the alarm signal _SAM from the overheat protection section 14, and when the device temperature is between the alarm temperature _TAM and the shutdown temperature _TSD , the alarm signal _SAM As long as is input, the timer operation is continued, and when the timer operation is continued for a predetermined time, the shutdown signal _SSD is output to the control unit 12. Further, the timer unit 16 resets the timer operation if the input of the alarm signal _SAM from the overheat protection unit 14 is stopped before the timer operation continues for a predetermined time even if the timer operation is started. The display unit 18 displays whether the device temperature is in a normal temperature, an alarm temperature, or a shutdown temperature.

[0011] Control unit 12 responds to the presence or absence of the input of the shutdown signal S _SD from the alarm signal S _AM, the shutdown signal S _SD presence of the input of and the timer unit 16 from the overheat protection unit 14, controls the display unit 18 If neither signal is input, the display unit 18 displays a temperature indicating that the device temperature is in a normal temperature state, and outputs an alarm signal S _AM
Is input, a temperature display indicating that the device temperature is in an alarm state is displayed, and when a shutdown signal _SSD is input, a temperature display indicating that the device temperature is in a shutdown state is displayed. When the shutdown signal _SSD is input, the control unit 12 controls the converter unit 4 to stop the output, that is, to shut down the output.

The overheat protection section 14 will be described with reference to FIG.

The overheat protection section 14 has a temperature sensing element TH. The temperature sensing element TH is composed of a thermistor, a thermocouple, or the like, is attached directly to or around the heat-generating electronic component, and outputs a device temperature detection signal corresponding to the temperature of the attached ambient. This temperature sensing element TH includes a series connection of resistors R1 and R2, and resistors R3 and R2.
And three series-connected bodies are connected in parallel. Resistance R
1 and R2 are connected to the input (-) of the alarm comparator ACP. An alarm reference power supply _EAM corresponding to the alarm temperature _TAM is connected to the input section (+) of the alarm comparator ACP. The connection between the resistors R3 and R4 is connected to the input (-) of the shutdown comparator SCP. Input of the shutdown comparator SCP (+) The shutdown temperature T _SD corresponding shutdown reference voltage source E
_SD (Voltage <reference power E _SD of the voltage of the reference power supply E _AM) is connected. The timer section 16 is connected to an output section of the alarm comparator ACP, and starts a timer operation when an alarm signal _SAM is input from the alarm comparator ACP.

Referring to FIG. 2 and FIG.
The operation of the timer 16 will be described. In FIG. 3, the vertical axis represents temperature, and the horizontal axis represents time. When the heat-generating electronic component generates heat, the temperature of the temperature-sensitive element TH rises and its resistance value increases. As a result, the voltage between both ends which is the device temperature detection signal of the temperature sensing element TH increases. Then, the resistor R1 when the device temperature reached alarm temperature T _AM at the time t1 to rise,
The connection voltage of R2 becomes higher than the voltage of the alarm reference power supply _EAM . As a result, an alarm signal _SAM is output from the alarm comparator ACP. The alarm signal _SAM is input to the timer unit 16 and the control unit 12. Timer section 16
Starts the timer operation in response to the input of the alarm signal _SAM . The control unit 12 causes the display unit 18 to display an alarm in response to the input of the alarm signal _SAM . Alarm comparator AC
P continues to output the alarm signal _SAM as long as the device temperature is equal to or higher than the alarm temperature _TAM , and the timer section 16 continues the timer operation as long as the alarm signal _SAM is input. When the timer operation period is a period of time T continues to time t2 the timer unit 16 of the timer unit 16 vary between alarm temperature T _AM and the shutdown temperature T _SD as device temperature indicated by the solid line shutdown Signal _SSD
Is output. This is because the device temperature is the shutdown temperature T _SD
Even if the temperature is below, the heat generating electronic components are adversely affected if the temperature is intermediate between the alarm temperature _TAM and the shutdown temperature _TSD and is at least continued for the period T. In this case, the timer section 16 outputs the shutdown signal _SSD . This is because it is preferable to shut down the switching power supply.

Further, after the device temperature rises as indicated by the dotted line and becomes equal to or higher than the alarm temperature T _{AM, the} temperature falls before the period T elapses, falls below the alarm temperature T _AM at time t3, and the alarm is compared. When the output of the alarm signal S _AM is stopped from vessel ACP timer 16 is reset will not continue the timer operation. In this case, the shutdown signal _SSD is not output from the timer section 16. The device temperature again becomes the alarm temperature T _AM at time t4 as shown by the dotted line.
As described above, the alarm signal S is output from the alarm comparator ACP.
_{When the AM} is output, the timer unit 16 starts the timer operation again.

Next, as shown by the broken line, the device temperature further rises above the alarm temperature T _AM and the shutdown temperature T
_{At SD} , the connection voltage of the resistors R3 and R3 becomes higher than the voltage of the reference power supply E _SD . As a result, a shutdown signal _SSD is output from the shutdown comparator SCP. Control unit 12 when the shutdown signal S _SD is input, while displaying that the shut down display unit 18 in response thereto, to shut down the output of the switching power supply controls the converter unit 6.

In the above-described embodiment, an alarm is displayed before the output is shut down due to an abnormal rise in the temperature of the device, such as the temperature of the heat-generating electronic components, so that the user can take necessary measures by using this alarm display. Becomes

The display on the display unit 18 will be described with reference to FIG.

As shown in FIG. 4A, the display unit 18
A light emitting element L1 having three light emitting elements such as EDs, which is turned on by the control output of the control unit 12 when the device temperature is normal, and lighted by the control output of the control unit 12 when the device temperature is in the alarm stage. The element L2 and the light emitting element L that is lit by the control output of the control unit 12 when the device temperature is in the shutdown stage
3 is comprised. In this case, when one of the light emitting elements is on, the other light emitting elements are off. The display unit 18 also includes an LED as shown in FIG.
And a light emitting element L1 that is turned on by the control output of the control unit 12 when the device temperature is normal, and blinks by the control output of the control unit 12 when the device temperature is in the alarm stage. Control unit 1 when temperature is in shutdown stage
The light emitting element L4 which is always lit by the control output of No. 2 may be used.

Referring to FIG. 5, a display example of the display unit 18 on the casing 20 of the switching power supply will be described. FIG.
FIG. 5A corresponds to FIG. 4A, and FIG.
This corresponds to (b). FIG. 5 (a) shows the casing 20.
In FIG. 5B, “normal”, “alarm”, and “stop” are written below each of the light emitting elements L1, L2, and L3. In FIG. 5B, the light emitting element L1 is “normal”, and the light emitting element L4 is “alarm (flashing)” and output. "Stop (lit)". The user can determine the state of the device temperature from the light emitting state of the light emitting element corresponding to the notation, and as a result, the user can take necessary measures from the light emitting state of the light emitting element corresponding to the notation.

Referring to FIG. 6, a description will be given of a case where a plurality of heat-generating electronic components are provided in the switching power supply instead of one. If there are a plurality of heat-generating electronic components inside the switching power supply and there is only one temperature measurement point by the temperature-sensitive element TH, the measured temperature at the temperature measurement point where the temperature-sensitive element TH is arranged is lower than the alarm temperature _TAM . Even so, the temperature may be equal to or higher than the alarm temperature T _{AM in} other places, or may be equal to the shutdown temperature T _SD . So 1
When the heat-generating electronic components 24 and 26 are attached to the two heat-radiators 22 or the separate heat-radiators 22, respectively, the temperature-sensitive elements TH1 and TH2 are provided directly on or around each of the heat-generating electronic components 24 and 26, respectively. The output of each of the temperature sensing elements TH1 and TH2 is connected to
4 ₁ and 14 ₂ (in this case, the temperature sensing elements TH1 and TH2).
2 is shown outside the overheat protection unit for the sake of understanding.
Include in overheat protection section. ), The alarm signal _SAM and the shutdown signal S from each of the overheat protection sections 14 ₁ and 14 _2.
SD is input to the control unit 12 via the OR gates 28 and 30. In this case, the number of temperature measurement points is two in the case of FIG. 6, and overheat protection can be performed more accurately. In addition,
In FIG. 6, the number is two, but the number of the temperature sensing element and the overheat protection portion may be more than three and the number of temperature measurement points may be three or more.

Referring to FIGS. 7 and 8, alarm temperature T
_A description will be given of an example in which _AM has a plurality of stages, in this example, an alarm temperature T _AM1 and an alarm temperature T _AM2 . Referring to FIG. 7, A is at the alarm temperature T _AM1 the device temperature rises a first alarm circuit unit for outputting an alarm signal S _AM1, B is raised to the device temperature further than alarm temperature T _AM1 and a second alarm circuit unit for outputting an alarm signal S _AM2 at the alarm temperature T _AM2 and, C is the shutdown signal becomes a shutdown temperature T _SD rises above the alarm temperature T _AM2 device temperature further rises and a shutdown circuit unit for outputting the S _SD. The first alarm circuit A, resistors R11, R12, alarm comparator ACP1, made from the alarm reference power source E _AM1, outputs an alarm signal S _AM1 by the temperature-sensitive element TH output corresponding to the alarm temperature T _AM1, second alarm the circuit portion B, resistors R12, R22, alarm comparator ACP2, made from the alarm reference power source E _AM2, outputs an alarm signal S _AM2 by thermosensor TH output corresponding to the alarm temperature T _AM2, shutdown circuit unit C, resistors R3, R4, shutdown comparator SCP, consists shutdown reference power supply ESD, the temperature sensing element corresponding to the shutdown temperature T _SD TH
The shutdown signal _SSD is output by the output.

The timer unit 16 ₁ outputs a shutdown signal S _SD in timer time T1 elapses, the timer unit 16 ₂ is arranged to output a shutdown signal S _SD timer time T2 elapses.

Therefore, when the temperature of the device rises and the time t
When the alarm temperature T _AM1 is reached at _{1, an} alarm signal S _AM1 is first output from the first alarm circuit section A, and at time t2 when the equipment temperature is intermediate between the alarm temperature T _AM1 and the alarm temperature T _AM2 , the time T1 elapses. shutdown signal S _SD output from the section 16 _1. Also, when the device temperature is at time t
5 When the alarm temperature T _AM 2 is reached, the second alarm circuit B
From alarm signal is output S _AM2, temperature alarm temperature T _AM 2 and the shutdown temperature T _SD intermediate in time T2
Shutdown signal S _SD is outputted from the timer unit 16 ₂ at the time t6 that elapses. When the temperature further rises and exceeds the shutdown temperature T _SD , a shutdown signal _SSD is output from the shutdown circuit section C. Therefore, in this example, since the alarm temperature is displayed in two stages, it is easier for the user to take necessary measures by a plurality of alarm stages until the output of the switching power supply is shut down. In this case, a corresponding display may be displayed on the casing of the switching power supply, as shown in FIG.

[0025]

As described above, according to the present invention, the following effects can be obtained.

According to the first electronic device of the present invention, in an electronic device that performs an overheat protection operation with respect to the device temperature, a change in the device temperature between a plurality of overheat protection temperatures and a temporal continuation of the change in the device temperature. Since the overheat protection operation is controlled based on the state, for example, when the overheat protection temperature is set to at least two stages of the first and second overheat protection temperatures, and when the device temperature exceeds the low first overheat protection temperature, Causes the electronic device to perform a required operation, for example, an alarm display, so that the device temperature is between the first overheat protection temperature and the second overheat protection temperature, and the time is long even if the device temperature is not so high. When the temperature of the device continues, if a malfunction occurs at the temperature of the device, it is possible to perform a required operation beyond the alarm, for example, a shutdown operation. Output are taken necessary measures before it is shut down.

According to the second electronic device of the present invention, in an electronic device which performs an overheat protection operation with respect to the device temperature, the first overheat protection is performed when the device temperature rises and exceeds the first overheat protection temperature. Display, and when a state in which the temperature of the device rises and is at an intermediate temperature between the first overheat protection temperature and the second overheat protection temperature has continued for a predetermined time, a second overheat protection display is performed. When the temperature rises and exceeds the second overheat protection temperature, a third overheat protection display is provided, so that the user can set the temperature before the equipment temperature rises to the second overheat protection temperature higher than the first overheat protection temperature. The required measures are taken by means of the first heating protection indication.

According to the third power supply of the present invention, a converter for converting an input voltage to a predetermined output voltage, an overheat protection unit for outputting an overheat protection signal when the temperature of the device reaches the overheat protection temperature, In a power supply device having a control unit that controls to be constant and performs heating protection control in response to the heating protection signal, the overheat protection unit increases the device temperature,
Outputs an alarm signal when the temperature exceeds the alarm temperature, outputs a shutdown signal when the temperature at the intermediate temperature between the alarm temperature and the shutdown temperature continues for a predetermined time, and outputs a shutdown signal when the temperature exceeds the shutdown temperature. The control unit performs the alarm display control and the shutdown control based on the alarm signal and the shutdown signal, so that the overheat protection temperature is set to at least two stages of the alarm temperature and the shutdown temperature,
The alarm display can alert the user that the device temperature is in the alarm state, and when the device temperature is abnormal, the output can be forcibly shut down.As a result, when the device temperature is abnormal, the output is shut down to ensure safe and internal operation. While preventing damage to circuit components and the like, the user is required to take necessary measures before the output is shut down by the alarm display before the device temperature becomes abnormal.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a switching power supply according to an embodiment of the present invention.

FIG. 2 is a circuit diagram of an overheat protection unit in FIG. 1;

FIG. 3 is a diagram showing a change in device temperature for explaining the operation of the overheat protection unit in FIG. 2;

FIG. 4 is a diagram showing a configuration of a display unit according to the embodiment of the present invention.

5 is a front view of a casing of a switching power supply provided with the display unit of FIG. 4;

FIG. 6 is a circuit diagram of an overheat protection unit when there are a plurality of temperature sensing elements.

FIG. 7 is a diagram showing another modification of the overheat protection unit.

FIG. 8 is a diagram showing a device temperature change for explaining the operation of the overheat protection unit in FIG. 7;

[Explanation of symbols]

 Reference Signs List 2 input rectification smoothing unit 4 converter unit 6 output rectification smoothing unit 8 output voltage detection unit 12 control unit 14 overheat protection unit 16 timer unit 18 display unit

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5G053 AA14 BA06 CA01 CA04 DA03 EA03 EB02 5H730 AA12 AA17 AA20 AS01 BB23 BB43 CC01 EE01 FD01 FD61 FG01 XX19 XX38 XX42 XX50

Claims (5)

[Claims] An electronic device that performs an overheat protection operation with respect to a device temperature, wherein the overheat protection operation is performed based on a change in the device temperature between a plurality of overheat protection temperatures and a temporal continuation of the change in the device temperature. Controlling electronic devices. 2. An electronic device which performs an overheat protection operation with respect to a device temperature, a first overheat protection display is displayed when the device temperature rises and exceeds a first overheat protection temperature, and the device temperature rises. When the state at the intermediate temperature between the first overheat protection temperature and the second overheat protection temperature continues for a predetermined time, the second overheat protection display is performed, and the device temperature rises to the second temperature. Electronic equipment, wherein a third overheat protection display is performed when the temperature exceeds the threshold. 3. The electronic device according to claim 2, wherein the first overheat protection display is an alarm display indicating that the device temperature is in an alarm stage. A converter for converting an input voltage into a predetermined output voltage; an overheat protection unit for outputting an overheat protection signal when the temperature of the device reaches an overheat protection temperature; A power unit having a control unit for performing heat protection control in response to a signal, wherein the overheat protection unit outputs an alarm signal when the device temperature rises and exceeds an alarm temperature, and shuts down the alarm temperature and shuts down. A shutdown signal is output when the state at an intermediate temperature from the temperature has continued for a predetermined time, and a shutdown signal is output when the shutdown temperature is exceeded, the control unit outputs an alarm based on the alarm signal and the shutdown signal. A power supply device for performing display control and shutdown control. 5. The power supply device according to claim 4, further comprising a display unit for displaying said alarm.