KR890001291Y1 - Control circuit of microwaves apparatus - Google Patents

Abstract

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Description

Microwave Drive Control Circuit

1 is a drive control circuit diagram of the present invention.

2 is a waveform diagram of each part of FIG.

* Explanation of symbols for main parts of the drawings

1: Output control signal generator 2: Magnetron drive unit

3: peak detection part 4: control part

SCR ₁ : Thyristor TC ₁ : Triac

TS ₁ , TS ₂ : Trans MM ₁ : Monomulti

Com ₁ : comparator AND ₁ : endgate

D ₁ to D ₄ : Diodes R ₁ to R ₆ : Resistance

C ₁ : condenser

The present invention is a microwave oven control circuit for controlling the initial operation time of the high-voltage transformer applying the operating power to the magnetron in the microwave oven to heat food using ultra-high frequency generated from the magnetron It is about.

In the conventional microwave oven, when the user operates the microwave to output the high potential at the output terminal of the output control signal generator regardless of the cycle of the AC power input, the microwave power is immediately applied to the high voltage transformer to drive the magnetron. At the initial time when AC power is applied to the high voltage transformer, excessive inrush current is generated in the high voltage transformer, thereby destroying the high voltage transformer and shortening the service life of the magnetron.

In view of such a conventional deficiency of the present invention, the AC power is applied to the high-voltage transformer at the time when the voltage of the applied AC power reaches the highest point, that is, the time when the current is minimum, so that excessive inrush current does not occur. If it is described in detail by the accompanying drawings as follows.

FIG. 1 is a drive control circuit diagram of the present invention, and as shown therein, the primary side TS ₁₁ of the triac TC ₁ and the high voltage transformer TS ₁ controlled by the output control signal generator ₁ is alternating. In a microwave oven connected in series with the power source AC and the secondary side TS ₁₂ of the high voltage transformer TS ₁ is connected to the magnetron driver 2, the primary side TS _{21 is} connected to the AC power source AC. Inverting input terminal (-) of the resistor (R ₂ ) and the comparator (COM ₁ ) through the secondary side (TS ₂₂ ) of the supplied power transformer (TS ₂ ) through the diode (D _1, D ₂ ) and the resistor (R ₁ ), Commonly connected to the anode and the cathode of the diode (D ₃ ) (D ₄ ), the non-inverting input terminal (+) of the comparator (COM ₁ ) is connected in series with the cathode and anode of the diode (D ₃ ) (D ₄ ) The resistor R ₃ and the capacitor C ₁ are connected in common to form the peak detector 3, and the output side of the comparator COM _{1, which} is the output side of the peak detector 3, is the one input terminal of the AND gate AND ₁ . On It belongs and well connected to the other input terminal through a mono multi (MM ₁₎ connected to its output side to the gate of the thyristor (SCR _1), and the die of the thyristor (SCR ₁₎ cathode is the output control signal unit (1) of The output terminal A is connected to the collector of the transistor TR ₁ connected to the base via the resistor R ₄ , and the anode of the die Lister SCR ₁ is connected to the resistor R ₆ and through the resistor R ₅ . The control unit 4 is configured by connecting to the gate of the triac TC ₁ , and reference numeral Vcc in the figure represents a power supply terminal.

If described in detail the operation and effect of the drive control circuit of the present invention configured as described above.

When AC power is applied and power is applied to the power supply terminal Vcc, AC power is stepped down by the power supply TS ₂ , and the _second power is supplied through the diode D ₁ and D ₂ . After full-wave rectification as shown in (a) of FIG. ₁ , the signal is applied to the inverting input terminal (-) of the comparator COM ₁ through the resistor R ₁ .

At this time, the rising edge of the full wave rectified voltage (T ₁₎ in the inverting input terminal of the comparator (COM ₁₎ (-) is higher than the voltage the voltage applied to that applied to its non-inverting input terminal (+), the comparator (COM ₁ As shown in (b) of FIG. 2, a low potential is outputted at the output side of the circuit), and the rectified voltage is charged to the capacitor C ₁ through the diode D ₃ and the resistor R ₃ , and the falling section In T ₂ , the voltage charged in the capacitor C ₁ flows through the resistor R ₃ and the diode D ₄ , and the voltage applied to the non-inverting input terminal (+) of the comparator COM ₁ is the inverting input terminal. Since it is higher than the voltage applied to (-), the high potential is output to the output side of the comparator (COM ₁ ) so that the trigger terminal of the monaural multi (MM ₁ ) At the same time as the trigger signal is applied to one input terminal of the AND gate (AND ₁ ).

Here, moneo multi (MM ₁₎ on the high potential period (T ₄₎ of the comparator (COM ₁₎ the high potential time slightly longer moneo multi (MM ₁₎ than that (T ₃₎ of the pulse signal outputted from the pulse signal output from the When the time constant is set, a pulse signal is output to the output terminal Q of the multi-mm MM ₁ as applied to the other input terminal of the AND gate AND ₁ as shown in FIG. the output side of the (aND ₁₎ there is from the peak of the full wave rectified voltage is a pulse signal of predetermined width output, as shown in the second degree (d), is applied to the gate of the output pulse signal are thyristors (SCR ₁₎ However, at this time, the transistor TR ₁ is turned off so that the thyristor SCR ₁ is not conducting.

In this state, when the user operates the microwave oven, when a high potential is output from the output terminal A of the output control signal generator _{1 at} the time t ₁ , as shown in FIG. The high potential is turned on by being applied to the base of the transistor TR ₁ through the resistor R ₄ .

Therefore, when the high potential is output to the output side of the AND gate (AND ₁₎ to time (t ₂₎ in the ondoen state transistor (TR ₁₎ to the time (t ₁₎ is applied to the gate of the thyristor (SCR _1), die The Lister SCR ₁ is turned on so that the power of the power supply terminal Vcc flows to ground through the resistors R _{6 and} R ₅ , the thyristor SCR ₁ , and the transistor TR ₁ , and the gate of the triac TC ₁ . is applied with the low potential to the triac (TC ₁₎ is conductive, so AC power source (AC) is the primary side of the high voltage transformer (TS ₁₎ the primary side high voltage transformer (TS ₁₎ is being yiettara to (TS ₁₁₎ of the (TS ₁₁ ) Is applied to the secondary side TS ₁₂ of the high voltage transformer TS ₁ and is applied to the magnetron driver 2 so that the magnetron is driven.

Here, when the thyristor SCR ₁ is conducted, the triac TC ₁ is conducted so that the high voltage transformer TS ₁ is applied with the AC power source AC to the primary side TS ₁₁ . Since the AC power source AC is applied to the primary side TS ₁₁ of the high voltage transformer TS _{1 at} the time of reaching the voltage, that is, the minimum current, the initial excessive inrush current does not occur in the high voltage transformer TS ₁ .

In this way, the AC power source AC is applied to the primary side TS ₁₁ of the high voltage transformer TS ₁ and the magnetron driver 2 is driven at the output terminal A of the output control signal generator 1. When the low potential is output since the transistor (TR ₁₎ is applied with the low potential to the base off of the so thyristors (SCR ₁₎ is applied to the low-potential-off to the base of the thyristor (SCR ₁₎ is turned off, yiettara triac ( Since the high potential is applied to the gate of the TC ₁ ) and turned off, the AC power AC applied to the primary side TS ₁₁ of the high voltage transformer TS ₁ is cut off, and the magnetron driver 2 is not driven.

As described above, the present invention applies the AC power to the primary side TS ₁₁ of the high voltage transformer TS ₁ during the period when the voltage of the AC power source AC is the highest and the current is the lowest voltage. TS ₁ ) does not generate an initial excessive inrush current, thereby extending the service life of the magnetron as well as the service life of the high-voltage transformer (TS ₁ ).

Claims (1)

The primary side (TS ₁₁₎ of the triac (TC _1), and a high voltage transformer (TS ₁₎ to be controlled by the output control signal generation unit (1) connected in series to the AC power source (AC) and the high voltage transformer (TS ₁₎ In the microwave oven, the secondary side TS ₂₂ of the power supply transformer TS ₂ is connected to the anode and the cathode and the comparator COM ₁ of the diodes D ₃ and D ₄ through the diodes D ₁ and D ₂ . Is connected to the inverting input terminal (-) of the resistor, and a resistor (R ₃ ) and a capacitor (C ₁ ) connected in series with the cathode and the anode of the diodes (D ₃ ) and (D ₄ ) are connected to the non-inverting input terminal (+). by connecting its output to one input terminal of the aND gate (aND ₁₎ hereinafter and as well, and connected to the other input terminal through a mono multi (MM _1), the output of the aND gate (aND ₁₎ is a thyristor (SCR ₁₎ connected to the gate, lifting his enoic connected to the gate side of the triac (TC _1), and the cathode is an output terminal (a) of the generator (1) connected to the base side transfected Master drive control circuit of a microwave oven, characterized in that the configuration and connected to the collector of (TR _1).