JP5544509B2 - Phase control dimmer - Google Patents

Description

  The present invention relates to a phase control dimmer that performs dimming of a lamp such as an incandescent lamp by controlling power supplied to the lamp by phase control of an AC power source.

  2. Description of the Related Art Conventionally, there is known a phase control dimmer that performs dimming of a lamp such as an incandescent lamp by controlling power supplied to the lamp by phase control of an AC power source that turns on a switch element based on a synchronization signal.

  FIG. 1 is a circuit diagram showing a main configuration of a conventional phase control dimmer 9. FIG. 2 is a diagram showing voltage waveforms at points a to d of the conventional phase control dimmer 9. The phase control dimming device 9 includes a controlled circuit 101 including an incandescent lamp, and a control circuit 100 that performs dimming of the incandescent lamp by performing phase control on the controlled circuit 101 based on a zero-cross signal that is a synchronization signal. With. The controlled circuit 101 is a circuit in which a commercial power source AC is connected to an incandescent lamp via a triac. The zero cross signal is generated as follows.

  The phase control dimmer 9 performs full-wave rectification on the AC 100 V power supply voltage Va (see FIG. 2A) supplied from the commercial power supply AC by the diode bridge circuit DB1 (see FIG. 2B). The power supply voltage Vc having the waveform shown in FIG. 2C that has been full-wave rectified and passed through the resistor R2 is input to the photocoupler PH via the Zener diode D. Thereby, a current corresponding to the input voltage flows through the light emitting diode of the photocoupler PH, and the light emitting diode emits light. On the other hand, when the power supply voltage Vc having the waveform shown in FIG.

  A power supply voltage of +5 V generated from the commercial power supply AC is supplied to the collector terminal of the phototransistor of the photocoupler PH via the pull-up resistor R3. The control circuit 100 receives a zero-cross signal (see FIG. 2D) that becomes a ground level when the phototransistor of the photocoupler PH is turned on and becomes a high level when the phototransistor is turned off.

Then, the control circuit 100 performs phase control on the controlled circuit 101 based on this zero cross signal, and performs dimming of the incandescent lamp.
Patent Document 1 also proposes a phase control dimmer.

JP 2000-223284 A

  However, in the conventional phase control dimmer 9, an appliance such as an IH cooking appliance (hereinafter referred to as “noise generating appliance”) that easily generates harmonic noise and switching noise is connected to the same commercial power supply AC. , The waveform of the power supply voltage Vc at the point c may be disturbed near the zero cross (see FIG. 2C). Therefore, when the power supply voltage Vc is zero-crossed, the photocoupler PH is not turned off accurately, and the rising of the zero-cross signal may be disturbed or lost (see FIG. 2E).

  The reason why the photocoupler PH is not accurately turned off is considered to be that the noise generated by the noise generator is superimposed on the power supply voltage Vc, and the current continues to flow to the photocoupler PH in the vicinity of the zero cross.

  Therefore, in the conventional phase control dimming device 9, when a noise generating tool such as an IH cooking utensil is connected to the same commercial power supply AC, phase control is performed on the controlled circuit 101 based on an accurate zero cross signal. I could not. That is, the dimming of the incandescent lamp could not be performed accurately.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a phase control light control device that is configured so that the power supplied to the lamp can be accurately controlled even when there is an influence of noise, and the light control of the lamp can be performed accurately. .

  The phase control light control device of the present invention has the following configuration in order to solve the above problems.

In the phase control dimming device for dimming the lamp by controlling the power supplied to the lamp by the phase control of the AC power source that turns on the phase control switch element based on the synchronization signal,
A photocoupler that generates the synchronization signal at that timing by turning off when the power supply voltage input from the AC power supply is less than a first constant voltage ;
A Zener diode connected in series to the photocoupler;
A switching circuit having a series circuit that will be connected in parallel to the series circuit, the switch element and the first resistor of the photocoupler and the Zener diode,
A second resistor connected between the switch circuit and a power source;
A voltage detection circuit for detecting an instantaneous value of the power supply voltage;
The absolute value of the instantaneous value of the supply voltage, when it is in the following the first second constant voltage at a constant voltage or detected is the voltage detection circuit, and a control circuit for turning on the switching element It is characterized by that.

  According to this invention, dimming of lamps such as incandescent lamps and LEDs can be performed accurately without malfunction.

It is a circuit diagram which shows the main structures of the conventional phase control light control apparatus 9. FIG. It is a figure which shows the voltage waveform in each point a-d of the conventional phase control light control apparatus 9. FIG. It is a circuit diagram which shows the main structures of the phase control light control apparatus 1 which concerns on embodiment of this invention. It is a figure which shows the voltage waveform in each point ad of the phase control light control apparatus 1 which concerns on embodiment of this invention.

A phase control dimmer according to an embodiment of the present invention will be described below.

FIG. 3 is a circuit diagram showing a main configuration of the phase control dimmer 1 according to the embodiment of the present invention. FIG. 4 is a diagram illustrating voltage waveforms at the points a to d of the phase control dimmer 1. The phase control dimmer 1 includes a controlled circuit 101 including an incandescent lamp and a control circuit 100 that performs dimming of the incandescent lamp by performing phase control on the controlled circuit 101 based on a zero-cross signal that is a synchronization signal. And a voltage detection circuit 105 for detecting the value of the power supply voltage Vb output from the diode bridge circuit DB1, and a switch circuit 110 including a normally open switch element SW1 and a resistor R1. The controlled circuit 101 is a circuit in which a commercial power source AC is connected to an incandescent lamp via a triac. The zero cross signal is generated as follows.

  The phase control dimmer 1 performs full-wave rectification on the AC 100 V power supply voltage Va (see FIG. 4A) supplied from the commercial power supply AC by the diode bridge circuit DB1 (see FIG. 4B). The power supply voltage Vc ′ having the waveform shown in FIG. 4C that has been full-wave rectified and passed through the resistor R2 is input to the photocoupler PH via the Zener diode D. Thereby, a current corresponding to the input voltage flows through the light emitting diode of the photocoupler PH, and the light emitting diode emits light. On the other hand, when the power supply voltage Vc ′ having the waveform shown in FIG.

  A power supply voltage of +5 V generated from the commercial power supply AC is supplied to the collector terminal of the phototransistor of the photocoupler PH via the pull-up resistor R3. The control circuit 100 receives a zero cross signal (see FIG. 4D) that becomes a ground level when the phototransistor of the photocoupler PH is turned on and becomes a high level when the phototransistor is turned off.

  Then, the control circuit 100 performs phase control on the controlled circuit 101 based on this zero cross signal, and performs dimming of the incandescent lamp. More specifically, the control circuit 100 controls the power supplied to the incandescent lamp by controlling the phase at which the triac is turned on based on the zero cross signal, and performs dimming of the incandescent lamp.

  However, also in the phase control dimmer 1 in this embodiment, appliances such as IH cooking appliances (hereinafter referred to as “noise generating appliances”) that easily generate harmonic noise and switching noise are connected to the same commercial power supply AC. In this case, the waveform of the power supply voltage Vc ′ at the point c ′ may be disturbed near the zero cross (see FIG. 4C).

  Therefore, in the phase control dimmer 1 in this embodiment, the voltage detection circuit 105 and the switch circuit 110 are provided so that the power supplied to the incandescent lamp can be accurately controlled even if there is an influence of noise. Specifically, the configuration is as follows.

The voltage detection circuit 105 detects an instantaneous value of the power supply voltage Vb output from the diode bridge circuit DB1. When the voltage detection circuit 105 detects that the value of the power supply voltage Vb is equal to or lower than the predetermined voltage value Vth0 (second constant voltage) , the voltage detection circuit 105 inputs the detection signal to the control circuit 100. Here, the predetermined voltage value Vth0 is, for example, + 60V.

  When the control circuit 100 receives a detection signal from the voltage detection circuit 105 indicating that the value of the power supply voltage Vb has become equal to or lower than the predetermined voltage value Vth0, the control circuit 100 turns on the switch element SW1.

  Therefore, during a period in which the value of the power supply voltage Vb is equal to or higher than the predetermined voltage value Vth0, the switch element SW1 is turned off, and a current corresponding to the input voltage flows through the light emitting diode of the photocoupler PH, so that the light emitting diode emits light. The value of the power supply voltage Vc ′ in this case is a value obtained by adding the Zener voltage of the Zener diode D and the forward voltage drop of the light emitting diode of the photocoupler PH.

  The switch element SW1 is also turned on during a period in which the value of the power supply voltage Vb is less than the predetermined voltage value Vth0 and the photocoupler PH is turned on (for example, 15 V or more and less than 60 V), but the current corresponding to the input voltage Flows into the light emitting diode of the photocoupler PH, and the light emitting diode emits light. The value of the power supply voltage Vc ′ in this case is also a value obtained by adding the Zener voltage of the Zener diode D and the forward drop voltage of the light emitting diode of the photocoupler PH.

Then, the photocoupler PH is turned off during a period in which the value of the power supply voltage Vb is less than the predetermined voltage value Vth0 and is a low voltage value (eg, less than 15V, the first constant voltage ) at which the photocoupler PH is turned off. During this period, since the switch element SW1 is on, the current output from the diode bridge circuit DB1 and passing through the resistor R2 flows to the resistor R1. Therefore, even if the noise generating instrument is connected to the same commercial power supply AC and the noise generated by the noise generating instrument is superimposed on the power supply voltage Vc ′, the noise current is bypassed toward the resistor R1. Therefore, when the noise generator is connected to the same commercial power supply AC, even if the waveform of the power supply voltage Vc ′ at the point c ′ is disturbed near the zero cross, the photocoupler PH is surely turned off when the power supply voltage Vc is zero crossed. It becomes a state.

  Therefore, in the phase control dimming device 1 according to this embodiment, even when the noise generating device is connected to the same commercial power supply AC, the phase control can be performed on the controlled circuit 101 based on the accurate zero cross signal. . That is, the dimming of the incandescent lamp can be performed accurately without malfunction.

  Note that, since the switch element SW1 is on during the period in which the value of the power supply voltage Vb is less than the predetermined voltage value Vth0 and is a low voltage value (eg, less than 15V) at which the photocoupler PH is turned off, the value of the power supply voltage Vc ′ Is a value obtained by subtracting the drop voltage Ve of the resistor R2 from the power supply voltage Vb.

  Here, in the conventional phase control dimming device 9 shown in FIG. 1, the power supply voltage Vb is less than the predetermined voltage value Vth0 and is a low voltage value (eg, less than 15V) at which the photocoupler PH is turned off. Since the coupler PH is off, the value of the power supply voltage Vc becomes equal to the power supply voltage Vb.

Therefore, the value of the power supply voltage Vc ′ is represented by “Vc ′ = Vc−Ve”. That is, during the period in which the value of the power supply voltage Vb is equal to or lower than the predetermined voltage value Vth0 and is a low voltage value (for example, less than 15 V) at which the photocoupler PH is turned off, the value of the power supply voltage Vc ′ is the drop voltage The value of Ve is lower than that of the conventional phase control dimmer 9. That is, Vc ′ at the moment when the photocoupler PH is turned off is Vc ′ = Vc−Ve because Vb is divided by the resistor R2 and the resistor R1, which is lower than the conventional Vc. It becomes. Therefore, it is less susceptible to noise when there is no change in the timing at which the zero cross signal is output as compared with the conventional case. For this reason, even if the noise generated by the noise generator is superimposed on the power supply voltage Vc ′, the phase control dimmer 1 can absorb the noise as long as it falls within the range of the drop voltage Ve.

  In the above embodiment, the power supply voltage Vb output from the diode bridge circuit DB1 is detected. However, in the implementation, the power supply voltage Va input to the diode bridge circuit DB1 may be detected. In this case, the predetermined voltage value Vth0 may be set to a value corresponding to the power supply voltage Va.

DESCRIPTION OF SYMBOLS 1, 2, 9 ... Phase control light control apparatus 100 ... Control circuit 101 ... Controlled circuit 105 ... Voltage detection circuit 110 ... Switch circuit

Claims (1)

In the phase control dimming device for dimming the lamp by controlling the power supplied to the lamp by the phase control of the AC power source that turns on the phase control switch element based on the synchronization signal,
A photocoupler that generates the synchronization signal at that timing by turning off when the power supply voltage input from the AC power supply is less than a first constant voltage ;
A Zener diode connected in series to the photocoupler;
A switching circuit having a series circuit that will be connected in parallel to the series circuit, the switch element and the first resistor of the photocoupler and the Zener diode,
A second resistor connected between the switch circuit and a power source;
A voltage detection circuit for detecting an instantaneous value of the power supply voltage;
The absolute value of the instantaneous value of the supply voltage, when it is in the following the first second constant voltage at a constant voltage or detected is the voltage detection circuit, and a control circuit for turning on the switching element Phase control dimmer.

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