JPH0446071B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a phase control circuit.

Figure 1 shows a general phase control circuit that keeps the load voltage constant against fluctuations in power supply voltage. In the figure, _E1 is an AC power supply, L is an incandescent lamp, and A is a
is a phase control element composed of triax,
_C1 is a capacitor, B is a trigger element such as SBS or diac, and _R1 is a resistor. To explain the operation, a capacitor _C1 is charged from a power supply _E1 via a resistor _R1 and an incandescent lamp L, and when the voltage of the capacitor _C1 exceeds the breakover voltage _VBO of trigger element B, trigger element B is turned on. and capacitor
The charge of _C1 flows to the gate of triac A, turning on phase control element A and lighting lamp L. Trigger element B is turned on once for each half cycle of power supply _E1 , thereby turning triac A on for each half cycle, and turned off each time the supply voltage goes to zero for each half cycle.

In order to continuously vary the output of the incandescent lamp L in this circuit, the current flowing through the resistor _{R1 can be varied by continuously changing the value of the resistor R1 ,} or the current flowing through the resistor R1 can be varied in parallel with the capacitor _C1 . Put the resistor and resistor R ₁
It is preferable to divert the current flowing through the trigger element B and change the timing at which the trigger element B is turned on. However, in order to vary the output of the incandescent lamp L by applying an electric signal, a variable resistor is not suitable, and a transistor or the like is used.

However, when varying the output of the incandescent lamp L using a transistor, etc., it is necessary to convert the current to direct current, since elements such as transistors that vary the flowing current with electrical signals only operate with direct current, and when controlling the phase, a triax is required. The signal to turn on A needs to be synchronized with the AC power supply _E1 , and therefore, in addition to the transistor TR, a diode bridge DB, a transformer T, a synchronization switch SW, etc. are required as shown in FIGS. 2 to 7. There was a problem that the circuit was complicated and large.

That is, in the circuits shown in FIGS. 2 to 5, the transistor TR is activated by an electric signal from the control DC power source _E2 .
By changing the current flowing through the capacitor _C1 , the charging current to the capacitor C1 is adjusted, thereby varying the output of the incandescent lamp L.
The current flowing through TR or resistor _R1 is triax A
turns on or the polarity of power supply _E1 changes.
Therefore, at this point, the current flowing through trigger element B becomes 0 and trigger element B is turned off, and synchronization is thereby automatically obtained. In the case of Figures 2 and 4. obtains the synchronization signal from the voltage of the triax A, and in the case of FIGS. 3 and 5, synchronization is obtained from the power supply _E1 . However, the second
The circuits shown in Figs. 3 and 3 require the use of the transistor TR in combination with the diode bridge DB, and in the case of Figs. 4 and 5, the output of the transformer T is converted to DC by the diode bridge DB. It is designed to be input to a relaxation oscillation circuit Q having a transistor TR, a control DC power supply _E2, etc., and requires a transformer T and a diode bridge DB. In addition, in the case of the circuits shown in FIGS. 3 and 5,
The transistor TR is not completely conductive, but the collector current of the transistor TR has a value proportional to the control DC power supply _E2 , and by changing the voltage of the control DC power supply _E2 , the collector current of the transistor TR is changed through the resistor _R1 . A part of the current flowing through the circuit is shunted. Therefore, when the voltage of the control DC power supply _E2 is changed,
The charging voltage of capacitor _C1 can be varied and phase controlled. Furthermore, in the circuits of FIGS. 2 and 3, one end of the control DC power source E ₂ is connected to the diode bridge DB, and the control DC power source E ₂
To obtain this from the power source _E1 , a transformer T etc. is required as shown in Part 6. That is, when it is desired to vary the power source _E2 with respect to fluctuations in the power source _E1 , it is necessary to isolate it from the power source _E1 via a transformer T or the like.

The present invention solves the above-mentioned problems, and is characterized by providing a triax A in series with the AC power source E ₁ and the load L, and providing a capacitor C ₁ charged by the AC power source E ₁ . , in a phase control circuit configured to turn on _the triax A when the charging voltage of the capacitor C ₁ is higher than a certain voltage, a pair of transistors TR ₁ that control all the charging currents that charge the capacitor C 1 ,
TR ₂ are connected in anti-parallel to each other, diodes D ₁ and D ₂ are connected in the forward direction to the transistors TR ₁ and TR ₂ , respectively, and the triac A is connected to a series circuit of the diode D ₁ and the transistor TR ₁ . are connected in parallel, a series circuit of the diode D ₂ and the transistor TR ₂ is connected in parallel, the capacitor C ₁ is connected between the output side of the triax A and the transistors TR ₁ and TR ₂ , and the diode D ₉
and a series circuit of a capacitor C ₉ and a diode D ₁₀ in the opposite direction to said diode D ₉ and a capacitor.
A series circuit of C ₁₀ is connected in parallel, and an adder/subtracter amplifier circuit G obtains an output by rectifying the load L voltage, and an output signal of the adder/subtracter amplifier circuit G and a Zener diode.
An error amplifier H obtains a control DC power supply _E4 by comparing the reference voltage generated by the ZD, and a control DC power supply by inverting the output signal of the error amplifier H.
A control circuit Q is provided, comprising an inverting amplifier I that obtains _E5 , and the output side of the error amplifier H of the control circuit Q is connected to the base of the transistor _TR1 , and the control circuit Q
The output side of the inverting amplifier I is connected to the transistor TR ₂
The charging voltage obtained by the capacitors C ₉ and C ₁₀ is connected to the base of the error amplifier
E' ₄ and E' ₅ are used, and the control circuit Q controls the transistors TR ₁ and TR ₂ in order to change the current flowing through the transistors TR ₁ and TR ₂ .

Hereinafter, the present invention will be explained according to the illustrated embodiment. In FIG. 7, TR ₁ and TR ₂ are transistors, E ₄ and E ₅ are control DC power supplies, D ₁ and D ₂ are diodes, and R ₂ , R ₃ is a resistor, transistor TR ₁ ,
TR ₂ are connected in antiparallel to each other, and diodes D ₁ and D ₂ are connected to each transistor TR ₁ and TR ₂ in the forward direction. And control DC power supply
E ₄ and E ₅ are obtained from the AC power supply E ₁ side, so that the output of the incandescent lamp L is constant against voltage fluctuations of the AC power supply E ₁ , and when the power supply voltage of the AC power supply E ₁ is low, the triax A is used. The configuration is such that the triac A is turned on at an early stage, and when the power supply voltage is high, the triac A is turned on at a later stage.

Further, a series circuit with a diode D ₉ and a capacitor C ₉ , and a series circuit with _{a diode D 10 and} a capacitor C ₁₀ in the opposite direction to the diode D 9,
A series circuit of this parallel circuit and a resistor _R16 is connected across the load L, and the capacitor is connected in parallel.
The charging voltage obtained by C ₉ and C ₁₀ is used as the control power supply.
As E′ ₄ , E′ ₅ , multiple operational amplifiers OP ₁ , OP ₂ ,
In the control circuit Q with OP ₃ , said transistor
_The transistors TR ₁ and TR ₂ are controlled to change _the current flowing through them.
The control power supplies E' ₅ and E' ₄ which are more positive and negative than the voltage applied to the load L are obtained through the resistor R ₁₆ , the diode D ₉ and the diode D ₁₀ . The control power supplies E′ ₅ and E′ ₄ are operational amplifiers.
Connected to the power terminals of OP ₁ , OP ₂ , and OP ₃ .

The operational amplifiers OP ₁ , OP ₂ , OP ₃ detect the lamp voltage of the incandescent lamp L using resistors R ₅ and R ₆ , and
Diodes D ₇ and D ₈ separate the positive lamp voltage signal and negative lamp voltage signal, and operational amplifier OP ₁ and resistors R ₇ , R ₈ , R ₉ , and R ₁₀ rectify the lamp voltage to the output of operational amplifier OP ₁ . get the output. In other words, the operational amplifier OP ₁ and the resistors R ₇ , R ₈ , R ₉ , and R ₁₀ constitute an addition/subtraction amplifier circuit G, which obtains a full-wave rectified signal by adding positive signals and subtracting negative signals. ing. Connect this signal to resistor _R11 and capacitor _C2
The control DC power source E ₄ is obtained by comparing the voltage with a reference voltage generated by a Zener diode ZD using an error amplifier H consisting of an operational amplifier OP ₂ and resistors R ₁₂ and R ₁₃ . _In addition, this signal _is passed through an _inverting amplifier I (amplification factor -
1) is reversed to obtain control DC power supply _E5 . The DC power supplies E ₄ and E ₅ cause the transistors TR ₁ and
Control the current charging capacitor _C1 via _TR2 . That is, when the power supply voltage increases and the lamp voltage increases, the output voltage of operational amplifier OP ₁ increases, and when it becomes higher than the reference voltage of Zener diode ZD, the output voltage of operational amplifier OP ₂ decreases, and the output voltage of operational amplifier OP ₃ also decreases. It gets lower. Therefore, the capacitor is connected via transistors TR ₂ and TR ₁ .
Since the current flowing through _C1 decreases and the voltage of capacitor _C1 rises slowly, the timing at which trigger element B turns on (the timing at which triac A turns on) is delayed, and the output decreases. On the other hand, when the power supply voltage is lowered, the lamp voltage is lowered and triac A is turned on earlier.

Next, the operation will be explained. All charging current flows through the capacitor _C1 via the transistor _TR1 or the transistor _TR2 . and control DC power supplies E ₄ , E ₅
Transistors TR ₁ , TR ₂
By changing the current flowing through the capacitor _C1 , the charging current to the capacitor C1 is adjusted, thereby varying the output of the incandescent lamp L. Diodes D ₁ and D ₂ are capacitors
This prevents the charge on _C1 from discharging.
In other words, for example, in the case of the polarity shown in the figure, if there is no diode D ₂ , the charge in the capacitor C ₁ will be discharged via the transistor TR ₂ because the transistor TR ₂ has the characteristic of conducting against reverse voltage. but,
This kind of fear will disappear.

According to the invention, a pair of transistors controlling the total charging current charging the capacitor _C1
TR ₁ and TR ₂ are connected in antiparallel _to each other, and a diode D _{1 ,}
Since D ₂ are connected respectively, the transistors TR ₁ ,
The load output can be varied continuously by sending an electrical signal to TR ₂ . Furthermore, a pair of transistors TR ₁ which controls all the charging currents charging the capacitor C ₁ ,
Since TR ₂ are connected in antiparallel to each other, the charging current to capacitor C ₁ can be more reliably and easily controlled by transistors TR ₁ and TR ₂ . Further, a series circuit of a diode D ₉ and a capacitor C ₉ and a series circuit of a diode D ₁₀ and a capacitor C ₁₀ in the opposite direction to the diode D ₉ are connected in parallel, and a series circuit of a diode D ₉ and a capacitor C ₉ is connected in parallel. and a series circuit of a diode D ₁₀ and a capacitor C ₁₀ in the opposite direction to the diode D ₉ are connected in parallel, and an adder/subtracter amplifier circuit G obtains an output by rectifying the load L voltage, and an output of the adder/subtracter amplifier circuit G. An error amplifier H obtains a control DC power source _E4 by comparing the signal with a reference voltage generated by a Zener diode ZD, and an inverting amplifier I obtains a control DC power source _E5 by inverting the output signal of the error amplifier H. and an output side of an error amplifier H of the control circuit Q is connected to the base of the transistor TR ₁ , and an output side of the inverting amplifier I of the control circuit Q is connected to the base of the transistor TR ₂ . , the charging voltage obtained by the capacitors C ₉ and C ₁₀ is used as the control power supply E' ₄ and E' ₅ of the error amplifier H, and the control circuit Q changes the current flowing through the transistors TR ₁ and TR ₂ . Therefore, transistor TR ₁ ,
Since TR ₂ is controlled, there is no need for a diode bridge or transformer for phase control as in the conventional case, and the control power supplies E' ₄ and E' ₅ are
It can be easily obtained by the voltage applied to the load L via the resistor R ₁₆ and the diodes D ₉ and D ₁₀ .
It has a very simple configuration, the entire circuit can be significantly miniaturized, and it can be provided at low cost, and its effects are significant.

[Brief explanation of the drawing]

1 to 6 are circuit diagrams showing conventional examples, respectively;
FIG. 7 is a circuit diagram showing one embodiment of the present invention. _E1 ...AC power supply, L...incandescent lamp, A...triax, _C1 ...capacitor, _TR1 , _TR2 ...transistor, _D1 , _D2 ...diode, _D9 , _D10 ...diode, _C9 , _C10 ... Capacitor, L...load, G...addition/subtraction amplifier circuit, ZD...zener diode, H...error amplifier, I...inverting amplifier, Q...control circuit.

Claims (1)

[Claims] 1. A triax A is provided in series with the AC power source E ₁ and the load L, and a capacitor C ₁ charged by the AC power source E ₁ is provided, and the capacitor C ₁
When the charging voltage of
In the phase control circuit configured to turn on, a pair of transistors TR ₁ and TR ₂ that control all the charging currents that charge the capacitor C ₁ are connected in antiparallel to each other, and each of the transistors TR ₁ and TR ₂ diodes D ₁ and D ₂ are respectively connected in the forward direction, and a series circuit of the diode D ₁ and the transistor TR ₁ is connected in parallel to the triax A;
A series circuit of the diode D ₂ and the transistor TR ₂ is connected in parallel, the capacitor C ₁ is connected between the output side of the triac A and the transistors TR ₁ and TR ₂ , and the diode D ₉ and the capacitor C ₉ are connected in parallel.
and a series circuit of a diode D ₁₀ and a capacitor C ₁₀ in the opposite direction to the diode D ₉ are connected in parallel, and an addition/subtraction amplifier circuit G obtains an output by rectifying the load L voltage, and the addition/subtraction amplifier circuit By comparing the output signal of G and the reference voltage created by the Zener diode ZD, the control DC power supply E ₄
and an inverting amplifier I that inverts the output signal of the error amplifier H to obtain a control DC power source _E5 , and the output side of the error amplifier H of the control circuit Q is connected to the transistor. The output side of the inverting amplifier I of the control circuit Q is connected to the base of the transistor _{TR 2} , and the charging voltage obtained by the capacitors C ₉ and C ₁₀ is connected to the control power supply E of the error amplifier H. ′ ₄ , E′ ₅ used,
In the control circuit Q, the transistors TR ₁ and TR ₂
In order to change the current flowing through the transistor,
A phase control circuit characterized in that it controls TR ₁ and TR ₂ .