KR940003773Y1 - Inverter circuit of electronic cooker - Google Patents

Abstract

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Description

Electronic cooker inverter synchronous circuit

1 is a conventional electronic cooker inverter synchronous circuit diagram.

2 is a waveform diagram of each part in FIG.

3 is an electronic cooker inverter synchronous circuit diagram of the present invention.

4 is a waveform diagram of each part in FIG.

* Explanation of symbols for main parts of the drawings

Q ₁ -Q ₆ : Transistor R / C: Capacitor

W ・ C: Working coil C ・ T: Current transformer

1-6: Comparator 7,8: Base Drive Circuit

The present invention relates to an electronic cooker, and more particularly, to an electronic cooker inverter synchronizing circuit which prevents damage of a power transistor caused by overlapping of a rising time of a power transistor in a two-seat inverter synchronizing circuit of an electronic cooker.

Conventional electromagnetic cooking inverter synchronization circuit is coupled to the base of the base drive circuit as illustrated in FIG. 1 (7) is a power transistor (Q ₁₎ (Q _2), the collector terminal of the power transistor (Q ₁₎ is It is connected to the emitter stage of the power transistor Q ₂ via a power supply V, and at the same time, a current transformer former C · T, a working coil C, and a resonant capacitor R / C) the via power transistors (emitter end and a power transistor (which is connected to the collector terminal of Q _2), larger rental trans permanent (C and T) of Q ₁₎ is a capacitor (C ₁₁₎ and a resistor (R ₁₁₎ The power supply Vcc is connected to the applied series resistor R ₁₂ (R ₁₃ ) and is connected to the inverting input terminal (-) of the comparator 1 and the input terminal (+) of the comparator 2, and the comparator 1 A series resistor (R ₁₄ ) (R ₁₅ ) to which the power supply (Vcc) is applied is connected to the input terminal (+) of the series, and a series resistor (Vcc) is applied to the inverting input terminal (-) of the comparator (2). (R ₂₀ ) (R ₂₁ ) is connected, and the output terminal of comparator (1) (2) is transistor (Q ₃ ) (Q) via resistor (R ₁₆ ) (R ₂₂ ) and capacitor (C ₁₂ ) (C ₁₄ ) ₄ ) is connected to the base terminal of the ground at the same time and connected to the grounded resistor (R ₁₇ ) (R ₂₃ ) and one end of the diode (D ₁₁ ) (D ₁₃ ), the collector terminal of the transistor (Q ₃ ) (Q ₄ ) a comparator (Vcc) is applied to a resistor (R ₁₈₎ (R ₂₄₎ through the one end of the connection and the emitter teodan once the earth resistance (R ₁₉₎ (R ₂₅₎ and capacitor _{(C 13) (C 15)} ( It is connected to the input terminal of 5), the output terminal of the comparator 5 is connected to the base driving circuit (7) and describes the operation state of the above configuration as follows.

Current of the first, the greater the rental trans permanent (C and T) a working coil (W and C) detected by the in is replaced by the voltage proportional to the current by a resistance (R _11), and the voltage supply (Vcc) The resistor R ₁₂ (R ₁₃ ) is shifted by a voltage applied to (a).

That is, in the initial state as shown in FIG.

In this way, the voltage having the initial state (b) is input to the inverting input terminal (-) and the input terminal (+) of each comparator (1) (2) and is caused by the resistors R ₁₄ , R ₁₅ and (R ₂₀ , R ₂₁ ). It is compared with the reference voltage (C) and (D).

At this time, the output of the comparator 1 becomes "high" when the "-" terminal voltage (b) of the comparator 1 is smaller than the comparison voltage (c) as shown in (b) of FIG. As shown in (c) of FIG. 2, when the output of the comparator 2 is larger than the comparison voltage (d) of the "+" terminal voltage (b), "high" is output and this signal (e) The transistor Q ₃ (Q ₄ ) is operated so that the input terminal (+) (-) of the comparator 5 has the same waveform as (g) (a) in (d) of FIG. As shown in (e) of FIG. 2, the output (child) is output as "high" when the "+" stage input (g) of the comparator 5 is larger than the "-" stage input (h), so that the base driving circuit 7 When input to the base driving circuit 7 drives the transistors Q ₁ , Q ₂ .

That is, when the transistor Q ₁ is "on", the transistor Q ₂ is "off", and when the transistor Q ₁ is "off", the transistor Q ₂ is "on" and the circuit is configured in the form of RLC series resonance. Thus, a standing wave current flows through the working coil WC.

However, because the drive to the two power transistors (Q ₁₎ (Q ₂₎ to the one sync signal, as shown in the second-degree (i) In the technical configuration described above of the power transistor (Q ₁₎ (Q ₂₎ The short-circuit state is overlapped by the “storage time + falling time” of the transistor “off” at the on / off intersection and the “rising time” of the “on” transistor. There was a problem that the power transistor is damaged.

Accordingly, the circuit configuration of the present invention that improves the above problems are as follows. In FIG. 3, the collector stage of the power transistor Q _{1 is} connected to the emitter stage of the power transistor Q ₂ via the power supply V, and at the same time, the current transformer C · T and the working coil W · C and a resonance capacitor via the (R / C) being connected to the collector terminal of the emitter end and a power transistor (Q ₂₎ of the power transistor (Q _1), large rental trans (C and T) a capacitor (C ₂₁₎ and a resistor (R _{21 is} connected to the series resistor R ₂₂ (R ₂₃ ) to which the power supply Vcc is applied, and at the same time, the inverting input terminal (-) of the comparator (1) (3) and the input terminal (+) of the comparator (2) (4). Is connected to the input terminal (+) of the comparator (1) and (3), and a series resistor (R ₂₄ , R ₂₅ ) (R ₃₆ , R ₃₇ ) to which power is applied is connected. The series inputs R ₃₀ and R ₃₁ (R ₄₂ and R ₄₃ ) to which the power supply Vcc is applied are connected to the inverting input terminal (−), and the output terminals of the comparators 1 to 4 are respectively the resistors R ₂₆ and R _32. , R _38, of R ₄₄₎ and capacitor _{(C 22, C 24, C} 26, C 28) via a transistor (Q ₃ ~ Q ₆₎ At the same time and connected to the device only ground resistance _{(R 27) (R 33)} (R 39) (R 45) and a diode _{(D 11) (D 13)} (D 14) being connected to one end of (D _16), transistor The collector stages of (Q ₃ to Q ₆ ) are connected to a resistor (R ₂₈ ) (R ₃₄ ) (R ₄₀ ) (R ₄₆ ) to which a power supply (Vcc) is applied, and the emitter stage is connected to a grounded resistor (R _29). , R ₃₅ ) (R ₄₁ , R ₄₇ ) and one of the condensers C ₂₃ , C ₂₅ (C ₂₇ , C ₂₉ ) are connected to the inputs of the comparators 5, 6 and the output of the comparator 5 Is connected to the base end of the transistor Q ₂ via the base driving circuit 7 and the output of the comparator 6 is connected to the base end of the transistor Q ₁ via the base driving circuit 8. Referring to the operation state and the effect of the same configuration in detail as follows.

The current of the third, the greater the rent transformer (C and T) a working coil (W and C) detected by the in is replaced by the voltage proportional to the current by a resistance (R _21), a voltage supply (Vcc) and the resistor Constant voltage by (R ₂₂ , R ₂₃ ) Is shifted by.

That is, as shown in FIG. 4, in the initial state, the voltage of the “I” stage maintains the “I” voltage state, and the voltages of the “I” stage are the inverting input stages of the comparators 1 and 3, respectively. (-) And the input voltage (+) of the comparators (2, 4) and the comparison voltage (R ₂₄ , R ₂₅ ) (R ₃₆ , R ₃₇ ) of the input terminals (+) of the comparators (1, 3) (E) and the comparison voltage (d) by the resistors R ₃₀ and R ₃₁ (R ₄₂ and R ₄₃ ) of the inverting input terminal (−) of the comparators 2 and 4 are compared.

At this time, when the output (g) of the comparator 1 is smaller than the voltage (c) of the input terminal (+) of the voltage (b) of the inverting input terminal (-) as shown in (a) (b) of FIG. is a - "is output (a) is a voltage (B) at the input terminal (+) is the inverting input terminal of the comparator (2) () greater than the voltage (d) in the" high "state of each transistor (Q ₃₎ (Q ₄ ), the input terminal (+) (-) of the comparator 5 has a waveform as shown in (c) of FIG. 4, and the output M of the comparator 5 has a comparator 5 as shown in (d) of FIG. ) Input is higher than the input of the "-" stage (ta), and when it is output (M) to the base driving circuit (7), the base driving circuit (7) is a comparator (5) When the output M is "low", the power transistor Q ₂ is "on" as shown in (h) of FIG. 4, and the output of the comparator 3 is (a) of FIG. As shown in (e), the voltage (b) of the inverting input terminal (-) is equal to the voltage (e) of the input terminal (+). When it is smaller, it becomes "high" and the output (difference) of the comparator 4 becomes "high" when the voltage of the input terminal (+) is greater than the voltage (bar) of the inverting input terminal (-). Q ₅ ) (Q ₆ ) is operated so that the input terminal (+) (-) of the comparator 6 has a waveform as shown in FIG. 4 (f), and the output P of the comparator 6 is shown in FIG. As described above, when the "+" stage input (bottom) of the comparator 6 is larger than the "-" stage input (za), when it is output (P) and input to the base driving circuit 8, the base driving circuit 8 Turns on the power transistor Q ₁ as shown in (h) of FIG. 4 when the output P of the comparator 6 is " low ".

Therefore, as shown in (h) of FIG. 4, a dead time occurs between the two power transistors Q ₁ and Q ₂ being “on”.

Therefore, the electronic cooker inverter synchronizing circuit according to the present invention prevents the two power transistors Q ₁ and Q ₂ from being overlapped and thus has an effect of preventing damage to the power transistor caused by a short circuit in the switching operation. .

Claims (1)

Current transformer (C, T) for sensing the current flowing through the working coil (W, C), a voltage (b) proportional to the current sensed by the current transformer (C, T) and the comparison voltage ( , Comparators 1 to 4 for operating transistors Q ₃ to Q ₆ by comparing the λ, bar, and voltages (e, eta) (waves) detected at the emitter terminals of the transistors Q ₃ to Q ₆ . Comparators 5 and 6 for comparing the lower and lower outputs to the base driving circuits 7 and 8 so as to have a dead time, and the output M of the comparators 5 and 6; And a base driving circuit (7) (8) for driving the power transistors (Q ₁ ) (Q ₂ ) according to (P).