JPS6318180Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrical device having an improved initialization circuit for resetting an electronic control unit when power is turned on.

Conventionally, an initialization circuit that resets an electronic control device when the power is turned on detects the output voltage of a constant voltage circuit, and when it detects a predetermined voltage that is slightly lower than the set voltage of the constant voltage circuit when the power is turned on, it triggers a switch, for example. The switching transistor is activated to start charging the capacitor of the time constant circuit, and the voltage generated between the terminals of this capacitor is supplied to the reset terminal of the electronic control circuit. The electronic control circuit remains in a reset state for a predetermined period of time until the lower threshold level of the reset terminal of the circuit is exceeded. However, with this configuration, it takes a certain amount of time for the capacitor in the time constant circuit to discharge after the power is turned off, so if the power is turned on again after a short power cut, the voltage across the terminals of the capacitor immediately after the power is turned off again. may already exceed the lower limit threshold level of the reset terminal of the electronic control circuit, and in this case there is a drawback that the electronic control circuit is not reset and malfunctions occur.

The present invention was developed in view of the above circumstances, and its purpose is to provide an initialization circuit that can reliably reset the electronic control circuit even when the power is turned on after being turned off for a short time, thereby preventing malfunctions. There is no electrical equipment to provide.

An embodiment of the present invention will be described below with reference to the drawings. Reference numeral 1 denotes a DC power supply device comprising, for example, a rectifier circuit and a smoothing circuit, to which AC power is applied from AC power supply terminals 2 and 3, and outputs DC between a positive output line 4 and a negative output line 5. Reference numeral 6 denotes a constant voltage circuit into which the DC from the DC power supply 1 is input, and as is well known, this circuit outputs a constant voltage between the positive power line 7 and the negative power line 8 when the input voltage is higher than a predetermined voltage. It is. Reference numeral 9 denotes an electronic control circuit such as an LSI, to which a positive power line 7 is connected to a positive terminal 9s, and a negative power line 8 is connected to a negative terminal 9d, which is also grounded. 10 is an initialization circuit, and in detail, 11 is a constant voltage diode as a constant voltage element that breaks over at voltage V _ds.The anode of this diode is connected to the positive power supply line 7, and the cathode is connected through a resistor 12. and connect it to the positive output line 4. 13 is a PNP type transistor as a switching element, and its base is connected to a constant voltage diode 1 via a resistor 14.
Connect the emitter to the positive output line 4, connect the collector to the negative power line 8 through resistors 15 and 16 in series,
The common connection point of 5 and 16 is connected to the reset terminal 9r of the electronic control circuit 9. Now, o ₁ and o ₂ are output terminals of the electronic control circuit 9, and when input information is given to the electronic control circuit 9 from an input device (not shown), the input information is inputted by the processing device in which the electronic control circuit 9 is built. is processed and a high or low output signal is output to the output terminals o ₁ and o ₂ . 17,1
8 is an NPN type transistor, the base of the transistor 17 is connected to the output terminal o ₁ via the resistor 19, and its collector is connected to the load circuit 2.
0, the base of the transistor 18 is connected to the output terminal o ₂ via the resistor 21, and its collector is connected to the load circuit 22. On the other hand, 23 is an NPN type transistor serving as a switching circuit, the base of which is connected to the reset terminal 9r via a resistor 24, and the collector connected to each emitter of transistors 17 and 18.
The emitter is grounded.

Next, the operation of this embodiment configured as described above will be explained with reference to the timing diagram shown in FIG. 2. _FIG . The voltage V ₁ between the power supply line 7 and the negative power supply line 8 is shown, and FIG. 2b shows the differential voltage V _d (=
V ₀ −V ₁ ), and FIG. 2c shows the reset terminal 9r.
FIG. 2d shows the AC power supply V _ac applied between the power supply terminals 2 and 3.

Now, when AC power is applied between the power supply terminals 2 and 3 at time t ₁ , as shown in Figure 2a, the DC power supply 1 has an internal smoothing circuit, so the voltage
As V ₀ gradually increases, the voltage V ₁ which is the output of the constant voltage circuit 6 also gradually increases at a voltage slightly lower than V ₀ . Then, when the voltage V ₁ reaches the specified voltage V _1a at time t ₂ , the voltage V ₁ becomes constant, and after that, only the voltage V ₀ increases, so that _the difference voltage
V _d increases gradually. Now, when time t ₃ is reached, the difference voltage
In order for V _d to reach V _ds , the constant voltage diode 11 breaks over and operates, causing the base current of the transistor 13 to flow and turning on the transistor 13, so that the output of the initialization circuit 10 as shown in FIG. rises from low to high.
That is, from time _t1 to _t3 , the output of the initialization circuit 10 is low and a reset signal is applied, and at time _t2 ', the voltage _V1 reaches the lower limit operating voltage _V1nio of the electronic control circuit 9. Since the electronic control circuit 9 is designed to operate normally, the electronic control circuit 9 is reset by the output (low) of the initialization circuit 10 applied to the reset terminal 9r between times _t2 ' and _t3 . At time _t3 , the reset signal is erased and the reset ends.
On the other hand, when the output of the initialization circuit 10 becomes high at time _t3 , the transistor 23 is turned on. The above is the operation when the power is turned on. After the reset is completed, the electronic control circuit 9 outputs high or low output signals to the output terminals O ₁ and O ₂ based on input information from an input device (not shown). When the output terminal O ₁ becomes high, the transistor 17 is turned on, and the load circuit 20 is energized through the transistors 17 and 23. When the output terminal O ₂ becomes high, the transistor 18 is turned on, and the load circuit 20 is energized through the transistors 18 and 23. The circuit 22 is energized and the electronic control circuit 9
The load circuits 20 and 22 are controlled by.

Now, when the AC power supply V _ac is turned off at time t ₄ , the voltages V ₀ , V ₁ , and V _d all gradually decrease.
Then, when the voltage reaches V _ds at time t ₅ , the voltage regulator diode 11 is cut off and the transistor 1
3 is turned off, the output of the initialization circuit 10 falls from high to low (see Figure 2c).
Electronic control circuit 9 is reset. And the time
If the AC power supply V _ac remains cut off after time t ₄ , the voltages V ₀ , V ₁ , and V _d will remain the same after time t ₅ .
It continues to descend as shown by the solid line in the figure. However, the voltage V ₁ is the lower limit operating voltage of the electronic control circuit 9.
At time t ₆ , when V _1nio slightly drops, the AC power supply
When V _ac is reenergized, the voltages V ₀ , V ₁ , and V _d gradually increase from time t ₆ as shown by the two-dot chain line in FIG. 2, and at time t ₇ the differential voltage V _d is V _ds
When the value reaches , the output of the initialization circuit 10 rises from low to high (see the two-dot chain line in FIG. 2c).
In this case, as mentioned above, the time before time t ₇
Since the voltage V ₁ reaches the lower limit operating voltage V _1nio of the electronic control circuit 9 at t ₇ ', the electronic control circuit 9 is reset by the low level signal applied to the reset terminal 9r from time t ₇ ' to t ₇ . The reset is completed at time _t7 .

By the way, in the past, the initialization circuit inputs the output voltage V ₁ of the constant voltage circuit 6, and, for example, the second
As shown in the figure, when voltage V ₁ reaches V _1y (time
Since the configuration is such that the capacitor in the initialization circuit starts charging at time _t2 '') and the output voltage of the initialization circuit changes from low to high at time _t3 , the AC power supply _Vac is suddenly cut off at time _t4 . In this case, the initialization circuit changes the voltage V ₁ to V _1y
After the capacitor's discharge time has elapsed, the output voltage falls to a low level, so as mentioned above, when the AC power supply V _ac is reenergized at time t ₆ when the voltage V ₁ has slightly decreased from V _1nio , ,
The output of the initialization circuit remains high and the electronic control circuit 9 is not reset. In this case, the voltage supplied to the electronic control circuit 9 becomes lower than the lower limit operating voltage V _1nio during the middle of the process, so the electronic control circuit 9 This will cause malfunction.

Furthermore, the electronic control circuit 9 does not operate normally when the voltage supplied to it is less than V _1nio , and even if a reset signal is applied to the reset terminal 9r, the output terminal remains unchanged.
O ₁ and O ₂ may become high, but in this embodiment, they are turned on by the output of the initialization circuit 10.
Since the transistor 23 which is controlled to turn off is provided and connected in series with the transistors 17 and 18 which are controlled to turn on and off by the output terminals O ₁ and O ₂ , the electronic control circuit 9 can operate normally. Before time t ₃ and after time t ₅ when there is a risk of failure (between time t 5 and t ₇ if _the power is re-energized at time t ₆ )
Even if output terminals O ₁ and O ₂ become high and transistor 17 or 18 is turned on, transistor 23 is off, so load circuits 20 and 2 are turned on.
Therefore, the load circuits 20 and 22 are reliably prevented from malfunctioning when the power is turned on or off.

As is clear from the above description, the initialization circuit of the present invention, which detects the input voltage of the constant voltage circuit and operates it, does not have a time constant circuit like the conventional structure, and as soon as the input voltage falls below a predetermined voltage, electronic control is performed. Since a reset signal can be applied to the reset terminal of the circuit, the electronic control circuit can be reliably reset even if the power is turned off or turned off for a short time, and therefore the electronic control circuit can be reset even if the power is turned off or turned off for a short time. Even when energized, the electronic control circuit does not malfunction unlike conventional structures, and it is possible to provide an electrical device that operates reliably.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is an electric circuit diagram, and FIG. 2 is a timing chart. In the drawing, 1 is a DC power supply, 2 and 3 are power terminals, 6 is a constant voltage circuit, 9 is an electronic control circuit, 9r is a reset terminal, 10 is an initialization circuit, 11
is a constant voltage diode (constant voltage element), 13 is a transistor (switching element), 20 and 22 are load circuits, and 23 is a transistor (switching circuit).

Claims (1)

[Claims for Utility Model Registration] 1. In a device that supplies power from a DC power source to an electronic control device via a constant voltage circuit, a reset terminal provided in the electronic control device and an input voltage of the constant voltage circuit A constant voltage element is activated when the voltage difference between the output voltage and the output voltage exceeds a predetermined voltage, and a reset signal is applied to the reset terminal when the voltage difference is below a predetermined voltage and the constant voltage element is in an inoperable state. 1. An electrical device comprising: an initialization circuit including a switching element that erases the reset signal when the constant voltage element goes into operation after exceeding a certain voltage value. 2. A request for registration of a utility model characterized in that the electronic control circuit has a switching circuit that is turned off by a reset signal from a switching element of the initialization circuit, and the switching circuit cuts off the output signal from the electronic control device. Electrical equipment described in item 1 of the scope.