KR940000972Y1 - Driving control circuit of electric cooker - Google Patents

Abstract

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Description

Drive control circuit of electronic cooker

1 is a conventional circuit diagram.

2 is a drive control circuit diagram of the inventive electronic cooker.

* Explanation of symbols for main parts of the drawings

TR ₂₀ -TR ₂₃ : Transistor R ₂₀ -R ₂₈ : Resistance

C ₂₀ -C ₂₃ : condenser CP ₂₀ : comparator

80: inverter drive unit

The present invention relates to a drive control circuit of an electronic cooker in an electronic cooker for heating food with a magnetic field generated by a current flowing through a working coil, and in particular, an inverter driver for controlling driving of a driving transistor of an inverter unit. The present invention relates to a drive control circuit of an electronic cooker configured to reduce the manufacturing cost and improve the manufacturing process point by a simple circuit.

As shown in FIG. 1, a conventional electronic cooker includes a rectifier 1 for rectifying an AC power source AC and an input sensing circuit unit for sensing a current input to the rectifier 1 through a CT. 4) and a digital / analog converter 5 for converting a digital signal output from the microprocessor to an analog signal according to a user-set output level, and the input sensing circuit section 4 and the digital / analog converter 5. An output comparison and search generation circuit unit 6 for outputting a control voltage and a predetermined search level as an output signal, a low pass filter 2 for filtering the output signal of the rectifier 1, and a current flowing through the working coil WC. Of the inverter unit 3 including the capacitors C ₁ , C ₂ , the working coil WC, the diode D ₁ , the driving transistor TR ₁ , and the inverter unit 3, The synchronous signal for driving the inverter unit 3 with the current flowing through the working coil WC Diodes D ₂ and D ₃ controlling the driving of the inverter unit 3 according to the synchronous circuit unit 7 to detect, the output comparison and output signals of the search generation circuit unit 6 and the synchronous circuit unit 7, and a resistor. (R ₁ -R ₁₆ ), the capacitor (C ₃ -C ₇ ), the comparator (CP ₁ ) and the transistor driving unit (8) consisting of transistors (TR ₂ -TR ₇ ), reference numeral 9 is a protective circuit portion, FU ₁ is a fuse.

In the conventional electronic cooker configured as described above, when AC power is applied and power is applied to the power terminals V _cc , V _EE , and (-V _EE ), the AC power supply AC is rectifier 1. And after rectifying and filtering through the low pass filter (2) is applied to the collector of the drive transistor (TR ₁ ) through the working coil (WC) of the inverter unit 3, the output signal of the inverter driver 8 as described later As a result, the driving transistor TR ₁ repeats the on and off operations to generate a magnetic field in the working coil WC.

At this time, the magnetic load of the appropriate load is placed on the cooker, the current is output to the output comparison circuit and the search generation circuit section 6 by outputting a constant voltage from the input sensing circuit section 4 through the current transformer CT.

In this case, when the user sets the power level, the power level control signal is output from the microprocessor and converted into the analog voltage level by the digital / analog converter 5 and then applied to the output comparison and search generation circuit unit 6. The output comparison and the search generation circuit section 6 are compared with the sensed voltage of the input sensing circuit section 4 applied above, and a control voltage of magnitude proportional to the difference of the voltages is output from the output comparison and search generation circuit section 6. Is applied to the non-inverting input terminal (+) of the comparator CP ₁ of the inverter driving unit 8, and at this time, the power of the power supply terminal V _CC is charged to the capacitor C ₃ through the resistor R ₁ . the inverting input terminal of the (CP ₁₎ (-) since the applied before the predetermined voltage is charged in the capacitor (C ₃₎ there is a high potential at the output terminal of the comparator (CP ₁₎ output being in the open state, yiettara power supply terminal The power supply of (V _CC ) is resistor (R ₂ ) The capacitor C ₄ is charged to the emitter of the transistor TR _{2 while} being charged.

Therefore, in this case, when the charging voltage of the capacitor C ₄ is greater than the predetermined voltage, a high potential is output to the collector of the transistor TR ₂ , and the transistor TR _{3 is} provided through the resistor R ₇ and the capacitor C ₆ . an on because is also on the transistor (TR _4), thus the transistor (TR ₆₎ (TR ₇₎ is off, the transistor (TR ₅₎ is turned on the power supply terminal (V _EE) power transistors (TR ₅₎ and It is applied to the base of the driving transistor TR ₁ of the inverter unit 3 through the resistor R ₁₂ and is turned on so that the output voltage of the low pass filter 2 is driven through the working coil WC. ₁ ) flows.

In the reverse case, that is, when the low potential is output to the output terminal of the comparator CP ₁ of the inverter driver 8, the voltage charged in the capacitor C ₄ is discharged to collect the transistor TR ₂ . since the low potential is output to the transistor _{(TR 3), (TR 4} ), (TR 5) is turned off, yiettara _{(TR 6), (TR 7} ) are turned on transistor for driving of the drive unit (3) (TR ₁ Base low potential is applied so that it remains off so that no current flows into the working oil (WC).

That is, the above operation is repeated to cook food in a magnetic field according to the current flowing in the working coil WC.

However, such a conventional electronic cooker is a factor of the cost increase of the product because the inverter driver 8 for controlling the driving of the driving transistor TR ₁ is not only complicated but also composed of a large amount of circuit elements. And defects such as a decrease in the points of the manufacturing process.

The present invention has been devised to reduce the manufacturing cost and improve the manufacturing process point by configuring the inverter driver as a simple circuit in view of such a conventional defect, which will be described in detail with reference to the accompanying drawings.

As shown in FIG. 2, the rectifier 1, the low pass filter 2, the inverter driver 3, the input sensing circuit 4, the digital / analog converter 5, the output comparison and the search generation circuit 6 In the electronic cooker comprising the synchronous circuit unit 7 and the inverter driver 8, the output comparison and search output circuit unit 6 and the output side of the synchronous circuit unit 7 are inverted input terminals (-) of the comparator CP ₂₀ . And a non-inverting input terminal (+), a reference voltage setting resistor (R ₂₀ ), and a capacitor (C ₂₁ ) through the diode (D ₂₀ ) in the reverse direction, and the output terminal of the comparator (CP ₂₀ ). The ruler is connected to the resistor R ₂₁ , the capacitor C ₂₁ , and the emitter of the transistor TR ₂₀ , and its base is connected to the resistor R ₂₂ (R ₂₃ ) connected to the power supply terminal V _CC . (TR ₂₀₎ of the collector is connected in parallel to a resistor (R ₂₃₎ and capacitor through the resistance (C ₂₂₎ (R ₂₄₎ and connected to the base of the transistor (TR ₂₁₎ his collector To the emitter and a common resistor (R ₂₅₎ and a transistor (TR ₂₂₎ and commonly connected to the base of (TR _23), an emitter resistor (R ₂₆₎ and then the transistor (TR ₂₃₎ over the transistor (TR ₂₂₎ Connected to the base of the driving transistor TR ₁ of the inverter section 3, the transistor TR ₂₁ emitter, the collector of the transistor TR ₂₃ , the resistor R ₂₇ , the resistor R ₂₆ connected in parallel, and An inverter driving unit 80 is configured by connecting a power supply terminal (-V _EE ) to the condenser C ₂₃ .

In the state where AC power is applied and power supply terminals V _CC and (V _EE ) (-V _EE ) power are applied, the same operation as in the prior art, that is, the output comparison and the search generation circuit unit ( When the control voltage is outputted in 6), the output control voltage is applied to the inverting input terminal (-) of the comparator CP ₂₀ of the inverter driver 8, and at this time, the power supply terminal V _{CC to the} capacitor C ₂₀ . Since the power of is charged through the resistor (R ₂₀ ) and applied to the non-inverting input terminal (+) of the comparator (CP ₂₀ ) as a reference voltage, the comparator (C ₂₀ ) before the constant voltage is charged to the comparator (CP ₂₀ ). The low potential is thrust at the output terminal of the power supply terminal (V _CC ) and the voltage charged to the capacitor (C ₂₁ ) through the resistor (R ₂₁ ) is discharged, so that the low potential is applied to the collector of the transistor TR ₂₀ The transistor TR ₂₁ is turned off so that the power supply of the power supply terminal V _EE passes through the resistor R ₂₅ . Since it is applied to the base of (TR ₂₂ ) (TR ₂₃ ), the transistor TR ₂₃ is turned off, the transistor TR ₂₂ is turned on, and the power supply of the power supply terminal V _EE is turned on in the transistor TR ₂₂ and the resistor R ₂₆ . Since it is applied to the base of the driving transistor TR ₁ of the inverter unit 3 through the on, accordingly, the filtered voltage output from the low pass filter 2 is driven through the working coil (WC) driving transistor ( TR ₁ ).

In the opposite case to the above, that is, when the high potential is output to the output terminal of the comparator CP ₂₀ , the output terminal of the comparator CP ₂₀ is configured as an open collector, so that it is in an open state, the power collector has a high potential through a resistor (R ₂₁₎ as charging the capacitor (C _21), so applied to the emitter of the transistor (TR ₂₀₎ in the case be greater than a certain voltage transistor (TR ₂₀₎ is output, and that The output high potential is applied to the base of the transistor TR ₂₁ and turned on so that the transistor TR ₂₂ is turned off, the transistor TR ₂₃ is turned on, and the base of the driving transistor TR ₁ of the inverter section 3 is turned on. The low potential is applied to it so that it remains off so that no current flows through the working coil WC.

That is, as described above, the above operation is repeated to control on and off of the driving transistor TR ₁ of the inverter unit 3, so that the food is cooked by a magnetic field corresponding to the current flowing through the working coil WC. do.

As described above, the inverter driving unit which controls the driving of the driving transistor of the inverter unit is configured by a simple circuit, thereby reducing the manufacturing cost and improving the point of the manufacturing process.

Claims (1)

The AC power supply AC is rectified and filtered by the rectifier 1 and the low pass filter 2 and supplied to the inverter unit 3, and the input sensing circuit unit 4 detects the input current of the rectifier 1. The driving transistor TR ₁ of the inverter unit 3 is supplied as a control voltage is supplied to the inverter driver 80 by comparing the voltage with the output voltage of the digital / analog converter 5 and the output comparison and the search generation circuit unit 6. In an electronic cooker in which a magnetic field is generated in the working oil (WC) by turning on and off), the output side of the output comparison and search generation circuit unit 6 and the output side of the synchronization circuit unit 7 are connected to the non-inverting input terminal. A transistor (TR ₂₀ ) connected to an inverting input terminal of the comparator (CP ₂₀ ) to which it is applied, and its output terminal connected to a resistor (R ₂₁ ), a capacitor (C ₂₁ ), and a resistor (R ₂₂ ), (R ₂₃ ) to a base. ), And the collector side of transistor TR ₂₀ connects to transistor TR ₂₁ ) And the collector side thereof is commonly connected to the base axes of the transistors TR ₂₂ and TR ₂₃ , and the emitter sides of the transistors TR ₂₂ and TR ₂₃ are connected to the base of the inverter section 3. A drive control circuit for an electronic cooker, comprising: an inverter drive unit (80) connected to a base of a drive transistor (TR ₁ ).