KR900000849Y1 - Reset protected circuit of microcomputer in power failure - Google Patents

Abstract

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Description

Microcomputer reset prevention circuit during momentary power failure

1 is a conventional circuit diagram.

2 is a circuit diagram of the present invention.

3 is a waveform diagram of the point (K) of the present invention.

* Explanation of symbols for main parts of the drawings

5: power supply unit 10: load current blocking unit

15: microcomputer reset unit 20: drive unit

25: display unit Q ₁ -Q ₉ : transistor

C ₁ -C ₅ : Condenser ZD ₁ , ZD ₂ : Zener Diode

R1-R ₂₃ : resistance

This invention is a washing machine. The present invention relates to a microcom reset prevention circuit during a momentary power failure, which prevents the reset of the microcomputer when a momentary power failure occurs in a product using a microcomputer, such as a microwave oven or a fan.

Conventionally, when a washing machine using a microcomputer generates a momentary power failure of more than several tens of msec or a voltage drop occurs instantaneously (several msec) due to power supply, the capacitor discharge time of the power supply unit is short because the load current during the washing machine is large. The result is faster time to reset the microcomputer.

Also. Using a microcomputer is reset when the power-on initial conditions because it goes by now been discarded is clear all the contents of the progress that was programs is a problem that must be re-select the stroke from the start occurs doemeurosseo large Conventionally capacity capacitor (3300 μ Fol a) The reset time was extended. This was not a reliable measure because of the large current consumption of the load, but a cost increase due to the large capacity of the capacitor. That is, in the past, when a momentary power failure occurred, the capacitor capacity of the power supply unit was increased to lengthen the discharge time, thereby making the reset point of the micom longer. Since the capacity of the system should be large, it was a factor in the cost increase.

In consideration of the above, the present invention cuts off the power supply of the driving part in advance in case of a momentary power failure of the product using the microcomputer, thereby eliminating the current consumption of the load and applying only the microcomputer consumption current, thereby preventing the reset of the microcomputer with a small capacitor. The reset protection circuit of the microcomputer during a momentary power failure will be described in detail with reference to the accompanying drawings.

1 is a conventional circuit diagram. AC power is passed through transformer (T _l ) and rectified and smoothed through bridge diode (BD) and electrolytic capacitor (C ₁ ), and then the electrostatic source is applied through regulator (REG) and ripple elimination capacitor (C ₂ ). The output of the bridge diode (BD) is applied to the base of the transistor (Q ₁ ) through the zener diode (ZD _I ) and the resistor (R ₂ ) (R ₃ ) and at the same time the resistor (R ₁ ) and the capacitor It is configured to be applied to the base of the transistor Q ₁ via (C ₃ ) and the collector side of the transistor Q ₁ connected to the base of the collector of transistor Q ₂ through the condenser C ₄ to the microcomputer MIC. Reset terminal Configure to be connected.

And second turning for the AC power supply (AC) is bit taenseu (T ₁₎ to go through the bridge diode (BD) and the electrolytic capacitor after the rectification smoothed through the (C ₁₎ resistance (R _l) and the constant voltage maintained by the circuit diagram of the subject innovation a Zener diode (ZD ₂₎ is connected to constitute the transfected G-Star (Q _l) and the ripple removing capacitor (C ₂₎ of the positive power supply known rotated portion 5 so as to output the through for.

In addition, the output of the bridge diode BD is connected to the base of the transistor Q ₂ connected to the resistors R ₂ and R ₃ through the zener diode ZD ₁ and the transistor Q connected to the resistor R ₉ and R ₁₀ . _It is configured to be applied to the base of ₆ ) and the load current breaker (10) by connecting the resistors (R ₄ -R ₈ ), transistors (Q ₃ -Q ₅ ) and the capacitor (C ₃ ) to the collector side of the transistor (Q ₂ ) and constitutes a transistor (Q ₆₎ has a configuration resistance (R ₁₁ -R ₁₃₎ and a capacitor (C ₁₎ and a transistor (Q ₇₎ connected to the microprocessor reset unit 15.

At this time, the collector output ① of the transistor Q ₅ is configured to be applied to the driving power supply terminal vcc of the driving unit 20 and the display unit 25. The collector output ② of transistor Q ₇ is a reset terminal of the microcomputer MIC. Organize to The control signal of the microcomputer (MIC) constitutes a known driver 20 to control the triac TR to which an AC power source AC is applied through the inverter LC ₁ , but the triac TR is a plurality of triacs. It is configured to control the motor, solenoid and water supply valve.

The display control signal of the microcomputer (MlC) also controls the soft butter IC ₂ and the transistors Q ₈ and Q ₉ to drive the display element LCD and the light emitting diode LED _l LED ₂ . The well-known display part 25 is comprised so that progress may be displayed.

In other words. According to the present invention, the display unit 25 controls the driving of the driving unit 20 which supplies the electrostatic source through the power supply unit 5 and operates the respective parts of the set according to the control signal of the microcomputer (MlC) and simultaneously displays the set progress. In controlling the driving of the). A load current blocking unit 10 for detecting a voltage variation of the power supply unit 5 and controlling the supply of the voltage Vcc of the driving unit 20 and the display unit 25; The microcomputer reset unit 15 detects the voltage variation of the power supply unit 5 and applies a reset voltage to the microcomputer ML.

In the present invention configured as described above, FIG. 1 is a circuit diagram of the related art, and the discharge time of the capacitor C ₁ is short due to the large load current during operation at the time of occurrence of instantaneous power failure. In order to prevent this, it is necessary to increase the capacity of the capacitor (C ₁ ) in order to prevent this, but this is the reason for the cost increase.

The present invention is configured as in Figure 2 to solve this problem.

In other words, FIG. 2 is a circuit diagram of the present invention, when AC 100V is input, a current of 10V is output at point A, and DC 5V is generated by a constant voltage circuit of zener diode ZD ₂ and transistor Q _l at point B. At point C, 4.7V and 4.7V are output from 10V of load A by 4.7V Zener diode (ZD _l ).

When AC 80V is input, current 8V is output at point A, DC 5V is output at point B by constant voltage circuit, and point C is 4.7V zener diode ZD ₁ at point A. DC 3.3V is outputted after subtracting 4.7V from 8V.

In this state, when the first AC voltage is applied at least 80 V, the normal case where the input voltage is 80 V or more is applied to the point C, which is 3.3 V or more, so that voltage division is performed at the base of the transistor Q ₂ , that is, the point D. Since 0.7 V or more is applied by the resistors R ₂ (R ₃ ), the transistor Q ₂ is turned “on” and when the transistor Q ₂ is “turned on”, the collector side is turned low and the transistor ( When Q ₃ ) is " turned on " and transistor Q ₃ is " turned on, " the collector side is at a high level, and transistor Q ₄ is " turned off ".

Transistor (Q ₄₎ is "turned off" if, the high transistor collector side that is point (H) of the transistor (Q ₅₎ Since the collector output of the low level of the (Q ₄₎ "turned on" by given transistor (Q ₅₎ By outputting the level voltage, the power supply (DC 5V) is applied to the power supply terminal Vcc of the drive inverter IC ₁ (IC ₂ ) of the known drive unit 20 and the display unit 25 so that the inverter LC ₁ ( Since the lC ₂ ) is operated, it is normally driven by the control signal of the microcomputer (MlC) and sends the control signal to the load, thereby the normal operation of the load.

But. Second, when the AC input voltage falls below 80V, when the AC input voltage falls below 80V or when a momentary power failure occurs, the point (A) falls below 8V and the point (C) falls below 3.3V. Since the voltage division resistor R ₂ (R ₃ ) takes 0.7 V or less at the base, that is, the point D of the Q ₂ ), the transistor Q ₂ is "turned off" and the transistor Q ₂ is "turned off". When the base side of the transistor Q ₃ , that is, the point E, is at a high level voltage, the transistor Q4 is turned "on", and when the transistor Q ₄ is turned "on", the collector side of the transistor Q ₄ is called the point. The high level voltage is applied to (G) so that the transistor Q ₅ is "turned off", and when the transistor Q ₅ is "turned off", the low level voltage is output to the collector side of the transistor Q ₅ , that is, the point H. be because the driving portion 20 and the display unit 25 drives the inverter that is connected to (IC ₁₎ power of (IC ₂₎ Here (Vcc) to the low level voltage is the dls even when the output control signal from the microprocessor (MIC), the driving portion 20 and the display unit 25 is not operating.

Therefore, there is no current applied to the fh load, and only the driving current of the microcomputer (MIC) itself is needed. Therefore, even if the capacitor (C ₁ ) is discharged during instantaneous power failure, the discharge time is long and the microcomputer (MlC) is returned when the AC power is normally restored. It will continue to carry out the ongoing administration without being set.

On the other hand, the operation of the microcomputer reset unit 15 is as follows.

At this time, if AC power is input at 100V, point A becomes 10V. Point (B) becomes 5V and point (C) becomes 5.3V by 4.7 Zener diode (ZD _l ) .When AC power is input to 60V, point (A) becomes 7V and point (B) becomes 5V. The point C becomes 2.3V by the 4.7V zener diode ZD ₁ .

Therefore, in the initial state of power-on, since the point I becomes low level by the voltage division resistor R ₉ (R ₁₀ ) until the point A becomes 7 V, the transistor Q ₆ is in the "turn-off" phase. When (Q ₇ ) is " turned on " so that the collector side of transistor Q ₇ , or point K, is at a low level state and point A is at 7V (i.e. point C is 2.3V), transistor (Q, ₆₎ of the base, the voltage dividing resistance _{(R (R 9) (R} 10) the voltage of the transistors (Q, ₆ takes over 0.7V) is by the "turn-on".

At this time, since the low level voltage is applied to the base side of the transistor Q ₇ , that is, the point J, and the transistor Q ₇ is "turned off", the high level voltage is applied to the collector side of the transistor Q ₇ , that is, the point K. Output terminal to reset microcomputer (MlC) The microcomputer (MlC) is operable by applying to.

But if the AC input voltage drops below 60V. After operating microcomputer (MlC), if AC input voltage drops below 60V due to voltage fluctuation, point (A) is below 7V. Point (C) is less than 2.3V, because of the base transistor (Q ₆₎ has been caught by 0.7V or less, by a voltage dividing resistance (R ₉₎ (R ₁₀₎ transistor (Q ₆₎ is to be "turned off".

When transistor Q ₆ is " turned off " transistor Q ₇ is " turned on " so that transistor Q ₇ is subjected to a low level voltage at the collector side, or point K, and thus the low level voltage at this point K. Is applied to the reset terminal _ of the microcomputer (MIC) to reset the microcomputer (MlC).

In other words, the present invention does not reset the microcomputer with a small capacitor during instantaneous power failure or voltage drop, and resets the microcomputer only when the voltage drops below 60V.

At this time, the applied voltage state of the point (K) of the present invention is shown in FIG.

As described above, the present invention increases the discharge time of the capacitor by operating the load current interrupting unit and the micom reset unit during a momentary power failure or voltage drop in a product using a microcomputer, thereby serving as a large capacitor even in a small capacitor. You can save costs.

Claims (1)

In the microcomputer using circuit in which the power supply unit 5 is configured and the driving unit 20 and the display unit 25 are connected to the microcomputer MIC, the voltage change of the power supply unit 5 is detected by the zener diode ZD _l to load current. The transistor Q ₂ of the blocking unit 10 and the transistor Q ₆ of the microcomputer reset unit 15 are configured to control driving, and the transistor Q ₂ is configured to control the multi-stage connected transistors Q ₃ -Q ₅ . Drive Q. The transistor Q ₆ is configured to reverse drive the transistor Q ₇ , and then the collector output of the transistor Q ₅ controls the power input of the driver 20 and the display 25. And the collector output of the transistor (Q ₇ ) is applied to the reset terminal of the microcomputer (MIC).