JP7345113B2 - Lighting systems and lighting equipment - Google Patents

Description

TECHNICAL FIELD The present disclosure relates to lighting systems and lighting fixtures. More specifically, the present invention relates to a lighting system including a power supply circuit and a control circuit, and a lighting fixture.

The lighting device of Patent Document 1 includes a light source unit and a power supply device. The power supply device includes a rectifier circuit, a power factor correction circuit, a step-down chopper circuit, and a control circuit, receives power from an external power source such as a commercial power source, and generates DC power for causing the light source unit to emit light. The rectifier circuit rectifies AC power and outputs DC power. The DC power output from the rectifier circuit is smoothed by a capacitor and then supplied to the power factor correction circuit. The power factor correction circuit boosts the DC power smoothed by the capacitor to improve the power factor. The step-down chopper circuit steps down the output voltage of the power factor correction circuit and supplies lamp current to the light source unit.

The control circuit controls the power factor correction circuit and the step-down chopper circuit. When the power switch is turned on, the control circuit starts each circuit within the control circuit according to a predetermined starting sequence, thereby causing the power supply device to start supplying output voltage and output current to the light source unit. When the lamp current flowing through the light source unit decreases due to a drop in power supply voltage or a power outage, if the lamp current remains almost zero for a predetermined period of time, a lamp current decrease error occurs and the control circuit shuts down the power supply. will be restarted. When the power supply voltage recovers from the power outage or drop during this restart period, the lamp current also recovers. Therefore, the lamp current returns to its normal value after restarting.

That is, the lighting device of Patent Document 1 restarts autonomously after the operation of the control circuit is reset when the lamp current continues to decrease for a predetermined period of time. Therefore, if the cause of the decrease in lamp current is a temporary decrease in power supply voltage, lighting of the light source unit can be restored without turning on the power switch again.

Japanese Patent Application Publication No. 2018-113175

Conventional lighting systems such as the power supply device of Patent Document 1 receive power from an external power source such as a commercial power source. ) may occur. Therefore, conventional lighting systems restart autonomously even if voltage sag occurs.

However, the operation of the lighting system upon restart from a voltage sag is the same as the operation upon normal startup of the lighting system. When a lighting system is normally started up, it takes a relatively long time for the lighting load to turn on steadily in order to ensure the time required for the voltage of each part in the lighting system to rise. Therefore, the time required for the lighting load to turn on steadily at the time of restart from an instantaneous voltage sag also becomes longer.

An object of the present disclosure is to provide a lighting system and a lighting fixture that can shorten the time required for a lighting load to turn on steadily when restarting from an instantaneous sag.

A lighting system according to an aspect of the present disclosure starts when an input voltage is supplied from an external power source, converts the input voltage into a voltage after starting, and supplies an output voltage to a lighting load; and a power supply circuit. A control circuit that controls the. The control circuit includes a signal generation circuit, a power supply control circuit, and a determination circuit. The signal generating circuit generates a periodically changing signal. The power supply control circuit starts controlling the power supply circuit when the number of cycles of the signal after the activation reaches a count threshold. The determination circuit determines whether a stop time, which is the time from when the power supply circuit is stopped until it is started, is less than or equal to a time threshold. The signal generating circuit sets the period of the signal to a first period if the stop time is longer than the time threshold, and sets the period of the signal to a first period shorter than the first period if the stop time is equal to or less than the time threshold. There are 2 cycles.

A lighting fixture according to one aspect of the present disclosure includes the above-described lighting system, a lighting load lit by the lighting system, and a fixture body that supports at least the lighting load.

The lighting system and lighting fixture of the present disclosure have the effect of shortening the time required for the lighting load to turn on steadily when restarting from an instantaneous voltage sag.

FIG. 1 is a circuit diagram showing a lighting system according to a first embodiment of the present disclosure. FIG. 2 is a circuit diagram showing a control circuit of the above lighting system. FIG. 3 is a time chart showing the operation of the above lighting system during normal startup. FIG. 4 is a time chart showing the operation of the above lighting system when restarting after an instantaneous drop. FIG. 5 is a circuit diagram showing a lighting system according to a second embodiment of the present disclosure. FIG. 6 is a circuit diagram showing a control circuit of the lighting system. FIG. 7 is a plan view showing a printed wiring board of a lighting system according to a third embodiment of the present disclosure. FIG. 8A is a front view of a lighting fixture according to a fourth embodiment of the present disclosure. FIG. 8B is a side view of the above lighting fixture.

The embodiments described below are merely examples of the present disclosure, and the present disclosure is not limited to the embodiments. If so, various changes can be made depending on the design etc.

The lighting system and lighting equipment of this embodiment are mainly used outdoors, such as in tunnels, roads, and playing fields. Further, the lighting system and lighting equipment of this embodiment can also be used indoors, such as in an office, factory, store, single-family house, or residential unit of an apartment complex.

Embodiments will be described below based on the drawings.

(First embodiment)
(1.1) Outline of Lighting System FIG. 1 shows a block configuration of a lighting system A1 that lights up the lighting load 3 as a lighting system of the first embodiment.

The lighting load 3 has a plurality of solid state light emitting elements. For example, the lighting load 3 includes an LED array in which a plurality of LEDs (Light Emitting Diodes) corresponding to a plurality of solid-state light emitting elements are connected in series. Note that the lighting load 3 is not limited to having an LED as a solid-state light emitting element. The lighting load 3 may include, for example, an organic EL (Organic Electro Luminescence, OEL) or other solid state light emitting device such as a semiconductor laser diode (LD). Furthermore, the number of solid-state light-emitting elements is not limited to a plurality, and may be one. Although the plurality of solid-state light emitting elements are electrically connected in series, the connection relationship is not limited to this. The electrical connection relationship between the plurality of solid-state light emitting elements may be a parallel connection or a combination of series connection and parallel connection.

The lighting system A1 includes a power supply circuit 1 and a control circuit 2 as main components.

The power supply circuit 1 converts an AC input voltage Vi supplied from an external power supply (for example, a commercial power system) 9 into a DC output voltage Vo. The power supply circuit 1 outputs an output voltage Vo from a pair of output terminals of the power supply circuit 1, and supplies a load current Io to a lighting load 3 connected to the pair of output terminals. The lighting load 3 is lit by the flow of the load current Io.

The control circuit 2 performs dimming control of the lighting load 3 by controlling the power supply circuit 1 based on a dimming signal Yd1 output from an external dimming device. The dimming signal Yd1 is a signal that notifies the dimming level instruction value (dimming instruction value) of the lighting load 3, and the control circuit 2 controls the dimming level of the lighting load 3 to match the dimming instruction value. The power supply circuit 1 is controlled accordingly.

(1.2) Power supply circuit The power supply circuit 1 has a rectifier circuit 11, a step-up chopper circuit 12, and a step-down chopper circuit 13, and converts the AC input voltage Vi supplied from the external power supply 9 into the DC output voltage Vo. Convert to

The rectifier circuit 11 includes, for example, a plurality of full-bridge connected diodes, performs full-wave rectification on the input voltage Vi, and outputs a DC rectified voltage V1. The boost chopper circuit 12 boosts the rectified voltage V1 and outputs a DC intermediate voltage V2. The step-down chopper circuit 13 steps down the intermediate voltage V2 and outputs a DC output voltage Vo. By applying the output voltage Vo across the lighting load 3, a load current Io flows to the lighting load 3, and the lighting load 3 is turned on.

(1.2.1) Boost Chopper Circuit The boost chopper circuit 12 includes a capacitor C1, an inductor L1, a switching element Q1, a diode D1, detection resistors R1 to R3, and a smoothing capacitor C2. The switching element Q1 is an N-channel enhancement type MOSFET (Metal Oxide Semiconductor Field Effect Transistor). Note that the switching element Q1 may be, for example, another semiconductor switching element such as a bipolar transistor in addition to the MOSFET. Smoothing capacitor C2 is, for example, an electrolytic capacitor.

Capacitor C1 is connected between the output terminals of rectifier circuit 11, and rectified voltage V1 is applied between the positive and negative electrodes of capacitor C1. A first end of the inductor L1 is connected to the positive electrode of the capacitor C1, and a second end of the inductor L1 is connected to the anode of the diode D1. The cathode of the diode D1 is connected to the positive electrode of the smoothing capacitor C2. The negative electrode of smoothing capacitor C2 is connected to the negative electrode of capacitor C1. The drain of the switching element Q1 is connected to the connection point between the inductor L1 and the diode D1 (the anode of the diode D1), and the source of the switching element Q1 is connected to the negative electrode of the capacitor C1. A series circuit of detection resistors R1 to R3 is connected between both ends of the smoothing capacitor C2. A gate of switching element Q1 is connected to control circuit 2. The control circuit 2 applies the gate signal Yg1 as a gate voltage between the gate and source of the switching element Q1, and turns on and off the switching element Q1 by adjusting the gate voltage.

When the switching element Q1 is turned on, current flows from the positive output end of the rectifier circuit 11 to the negative output end of the rectifier circuit 11 through the inductor L1 and the switching element Q1. This current causes magnetic energy to be stored in inductor L1. Next, by turning off the switching element Q1, the magnetic energy of the inductor L1 is released, and travels from the second end of the inductor L1, through the diode D1, the smoothing capacitor C2, and the capacitor C1, to the first end of the inductor L1. Current flows through the path. This current generates an intermediate voltage V2, which is the boosted rectified voltage V1, across the smoothing capacitor C2. The magnitude of intermediate voltage V2 is adjusted by making variable the duty (ratio of on time to switching period) of switching element Q1.

Intermediate voltage V2 is divided by a series circuit of detection resistors R1 to R3. The divided voltage generated by the series circuit of detection resistors R1 to R3 is output to the control circuit 2 as a voltage detection signal Ys1. The magnitude of the voltage detection signal Ys1 is proportional to the magnitude of the intermediate voltage V2.

(1.2.2) Step-down chopper circuit The step-down chopper circuit 13 includes a switching element Q2, an inductor L11, a capacitor C11, a diode D11, a detection resistor R11, and a resistor R12. Switching element Q2 is an N-channel enhancement type MOSFET. Note that the switching element Q2 may be, for example, another semiconductor switching element such as a bipolar transistor in addition to the MOSFET. The detection resistor R11 is a shunt resistor for current detection and has a low resistance value. The resistor R12 is a discharging resistor that discharges the capacitor C11, and has a high resistance value.

The drain of the switching element Q2 is connected to the positive electrode of the smoothing capacitor C2, and the source of the switching element Q1 is connected to the first end of the inductor L11. The second end of the inductor L11 is connected to the positive electrode of the capacitor C11, and the negative electrode of the capacitor C11 is connected to the first end of the detection resistor R11. The second end of the detection resistor R11 is connected to the negative electrode of the smoothing capacitor C2 and the anode of the diode D11. The cathode of the diode D11 is connected to the source of the switching element Q2 (the first end of the inductor L11). A resistor R12 is connected between both ends of the diode D11. A gate of switching element Q2 is connected to control circuit 2. The control circuit 2 applies the gate signal Yg2 as a gate voltage between the gate and source of the switching element Q2, and turns on and off the switching element Q2 by adjusting the gate voltage.

Then, when the switching element Q2 is turned on, a current flows from the positive electrode of the smoothing capacitor C2 to the negative electrode of the smoothing capacitor C2 through the switching element Q2, the inductor L11, and the capacitor C11. This current charges the capacitor C11 and stores magnetic energy in the inductor L11. Next, the switching element Q2 is turned off, and the magnetic energy of the inductor L11 is released, and a current flows from the second end of the inductor L11 through the capacitor C11 and the diode D11 to the first end of the inductor L11. flows. This current charges capacitor C11. As a result, an output voltage Vo obtained by stepping down the intermediate voltage V2 is generated between both ends of the capacitor C11. The magnitude of the output voltage Vo is adjusted by making the duty of the switching element Q2 variable.

A lighting load 3 is connected between both ends of the capacitor C11, and by applying an output voltage Vo between both ends of the lighting load 3, the step-down chopper circuit 13 outputs a load current Io. Load current Io flows through a series circuit of lighting load 3 and detection resistor R11. Therefore, a voltage proportional to the load current Io is generated across the detection resistor R11. The voltage across the detection resistor R11 is output to the control circuit 2 as a current detection signal Ys2.

Further, a winding Na is magnetically coupled to the inductor L11, and a first end of the winding Na is connected to the anode of the diode D21 and the anode of the diode D22. The second end of the winding Na is connected to the negative electrode of the smoothing capacitor C2. The cathode of the diode D21 and the cathode of the diode D22 are connected to the control circuit 2. If the input voltage Vi is supplied to the lighting system A1, an inductor current flows through the inductor L11 due to switching of the switching element Q2. At this time, an induced voltage due to the inductor current is generated between both ends of the winding Na as an internal voltage of the power supply circuit 1. The induced voltage is half-wave rectified by each of the diodes D21 and D22, and the voltage at the cathode of the diode D21 is outputted to the control circuit 2 as an output detection signal Ys31, and the voltage at the cathode of the diode D22 is outputted to the control circuit 2 as an output detection signal Ys32.

(1.3) Control circuit Normally, after a sufficient period of time has passed after the supply of the input voltage Vi to the lighting system A1 is cut off, the voltages (rectified voltage V1, intermediate voltage V2, adjustment voltage V2, The smoothed voltage of the optical signal Yd1, etc.) also decreases to around 0 (zero) V. In this embodiment, the dimming signal Yd1 is a PWM voltage signal that notifies a dimming instruction value based on the duty, and the control circuit 2 uses the DC smoothed voltage that is obtained by smoothing the dimming signal Yd1. , determine the dimming instruction value.

Then, when the input voltage Vi is supplied to the lighting system A1, the control circuit 2 starts up the power supply circuit 1. The control circuit 2 can detect supply and stop of the input voltage Vi based on the magnitude of the input voltage Vi. The control circuit 2 causes the lighting load 3 to steadily turn on after executing a predetermined startup sequence in order to suppress flickering of the lighting load 3 immediately after the power supply circuit 1 is started, and startup failures. For example, after starting, the lighting load 3 lights up steadily after passing through a first standby period, a second standby period, and a third standby period. The first standby period is the time required for the external dimming device that generates the dimming signal Yd1 to stabilize. The second standby period is a period required for stabilization of the intermediate voltage V2 output by the boost chopper circuit 12. The third standby period is a period during which the dimming level of the lighting load 3 is maintained at the dimming lower limit for soft start.

Here, the external power supply 9 may generate an instantaneous voltage drop (instantaneous voltage drop) in which the voltage drops instantaneously. An instantaneous sag is a phenomenon in which the input voltage Vi decreases over a period of, for example, several cycles to about 100 cycles of the input voltage Vi, and occurs over a period of about several tens of milliseconds to 2 seconds. In the event of an instantaneous voltage drop, the input voltage Vi returns to the rated voltage value in a short time. As a result, even if an instantaneous drop occurs, the voltage of each part within the lighting system A1 does not drop excessively. Therefore, even when restarting after an instantaneous voltage drop, if the startup sequence is the same as that used during normal startup, the lighting load 3 will turn on steadily even though the voltage of each part in the lighting system A1 has hardly decreased. It takes a relatively long time, just like during normal startup.

Note that momentary sag includes both momentary power outages and momentary voltage drops specified in JIS B9960-32:2011. In a momentary power outage, the interruption or no-voltage state of the power supply is for less than 3 msec at any point in the cycle of the supplied power, and the interval between interruptions is greater than 1 sec. In an instantaneous voltage drop, the amount of the drop is less than 20% of the peak value of the power supply, the duration of the drop does not exceed the length of one cycle, and the interval between drops exceeds 1 sec.

Therefore, the control circuit 2 determines whether the current startup is a normal startup or a restart after an instantaneous voltage drop, based on the output detection signals Ys31 and Ys32. Then, the control circuit 2 adjusts the dimming level of the lighting load 3 after the voltage drop by reducing the time required to turn on the lighting load 3 steadily when restarting after the voltage drop than during normal startup. To quickly return to the same dimming level as before the voltage drop. That is, the control circuit 2 shortens the time required for the lighting load 3 to turn on steadily at the time of restart from an instantaneous voltage sag.

The configuration and operation of the control circuit 2 will be described in detail below.

(1.3.1) Block Configuration of Control Circuit The control circuit 2 includes a power supply control circuit 21, a signal generation circuit 22, and a determination circuit 23, as shown in FIG.

The power supply control circuit 21 generates a gate signal Yg1 based on the voltage detection signal Ys1, and outputs the gate signal Yg1 to the gate of the switching element Q1. The gate signal Yg1 is a binary voltage signal that takes either an H level or an L level. When gate signal Yg1 is at H level, switching element Q1 is turned on, and when gate signal Yg1 is at L level, switching element Q1 is turned off. The power supply control circuit 21 adjusts the duty of the switching element Q1 by making variable the period during which the gate signal Yg1 is at H level with respect to the switching period. If the power supply control circuit 21 increases the intermediate voltage V2, it increases the duty of the switching element Q1. If the intermediate voltage V2 is to be lowered, the power supply control circuit 21 reduces the duty of the switching element Q1. That is, the power supply control circuit 21 controls the boost chopper circuit 12 to make the magnitude of the intermediate voltage V2 match the target voltage value.

Further, the power supply control circuit 21 generates a gate signal Yg2 based on the current detection signal Ys2, and outputs the gate signal Yg2 to the gate of the switching element Q2. The gate signal Yg2 is a binary voltage signal that takes either an H level or an L level. When gate signal Yg2 is at H level, switching element Q2 is turned on, and when gate signal Yg2 is at L level, switching element Q2 is turned off. The power supply control circuit 21 adjusts the duty of the switching element Q2 by making variable the period during which the gate signal Yg2 is at H level with respect to the switching period. If the power supply control circuit 21 increases the load current Io (increases the output voltage Vo), it increases the duty of the switching element Q2. If the power supply control circuit 21 reduces the load current Io (reduces the output voltage Vo), it reduces the duty of the switching element Q2. In other words, the power supply control circuit 21 controls the step-down chopper circuit 13 to adjust the magnitude of the output voltage Vo and make the magnitude of the load current Io match the target current value.

The determination circuit 23 determines whether the stop time, which is the time from when the input voltage Vi drops and the power supply circuit 1 stops until it starts, is less than or equal to the time threshold Tr (see FIG. 4). The time threshold value Tr is the upper limit value of the duration of an instantaneous voltage drop (instantaneous voltage drop) in which the input voltage Vi instantaneously decreases. That is, when the input voltage Vi decreases and then increases again, the determination circuit 23 determines whether the decrease in the input voltage Vi corresponds to an instantaneous sag. The determination circuit 23 outputs the determination result to the signal generation circuit 22 as a determination signal Ya1.

The signal generation circuit 22 generates a triangular wave signal Ya2, which is a triangular voltage signal, as a periodically changing signal. The signal generation circuit 22 sets the cycle of the triangular wave signal Ya2 to the cycle based on the determination signal Ya1 output by the determination circuit 23. In this embodiment, the signal generation circuit 22 switches the period of the triangular wave signal Ya2 to either the first period Tp1 or the second period Tp2 (see FIG. 4) based on the determination signal Ya1.

Then, the power supply control circuit 21 starts controlling the power supply circuit 1 when the number of cycles of the triangular wave signal Ya2 after startup reaches the count threshold.

(1.3.2) Circuit configuration of control circuit FIG. 2 shows a specific circuit configuration of the control circuit 2.

(judgment circuit)
The control circuit 2 includes, as a determination circuit 23, a comparator (first comparison circuit) K1, a comparator (second comparison circuit) K2, a resistor R33, a first time constant circuit CR1, a second time constant circuit CR2, and a DC power supply E1. Be prepared. The first time constant circuit CR1 is a parallel circuit of a resistor R31 and a capacitor C31, and the voltage across the capacitor C31 is set as a charging voltage Vc1. The second time constant circuit CR2 is a parallel circuit of a resistor R32 and a capacitor C32, and uses a voltage across the capacitor C32 as a charging voltage Vc2. The DC power supply E1 generates a DC voltage, and (the magnitude of) the DC voltage generated by the DC power supply E1 is set as a voltage threshold Vr1.

The output detection signal Ys31 is input to the first time constant circuit CR1, and the capacitor C31 is charged by the output detection signal Ys31. The output detection signal Ys32 is input to the second time constant circuit CR2, and the capacitor C32 is charged by the output detection signal Ys32. If the input voltage Vi is normally supplied, each of the charging voltage Vc1 and the charging voltage Vc2 becomes equal to or higher than the voltage threshold Vr1. Furthermore, when the input voltage Vi stops (or decreases), the charge in the capacitor C31 is discharged by the resistor R31, and the charging voltage Vc1 decreases. Similarly, when the input voltage Vi stops (or decreases), the charge in the capacitor C32 is discharged by the resistor R32, and the charging voltage Vc2 decreases.

The capacitance of capacitor C31 and the capacitance of capacitor C32 are equal. The resistance value of resistor R31 is greater than the resistance value of resistor R32. Therefore, the slope of increase in charging voltage Vc1 due to output detection signal Ys31 and the slope of increase in charging voltage Vc2 due to output detection signal Ys32 are equal to each other. On the other hand, the slope of decrease in charging voltage Vc1 due to resistor R31 is smaller than the slope of decrease in charging voltage Vc2 due to resistor R32. That is, the time constant during discharging of the second time constant circuit CR2 is smaller than the time constant during discharging of the first time constant circuit CR1. Note that the increasing slope of the charging voltage is the amount by which the charging voltage increases per hour, and the decreasing slope of the charging voltage is the amount by which the charging voltage decreases per hour.

The charging voltage Vc1 is input to the positive input terminal of the comparator K1, and the voltage threshold Vr1 is input to the negative input terminal of the comparator K1. The output of the comparator K1 is an open collector output, and the comparator K1 outputs the comparison result between the charging voltage Vc1 and the voltage threshold Vr1 as a binary signal of H level and L level. The comparator K1 outputs an H level when the charging voltage Vc1 is equal to or higher than the voltage threshold Vr1, and outputs an L level when the charging voltage Vc1 is less than the voltage threshold Vr1.

The voltage threshold Vr1 is input to the positive input terminal of the comparator K2, and the charging voltage Vc2 is input to the negative input terminal of the comparator K1. The output of the comparator K2 is an open collector output, and the comparator K2 outputs the comparison result between the charging voltage Vc2 and the voltage threshold Vr1 as a binary signal of H level and L level. The comparator K2 outputs an H level if the charging voltage Vc2 is less than the voltage threshold Vr1, and outputs an L level if the charging voltage Vc2 is equal to or higher than the voltage threshold Vr1.

The output of the comparator K1 and the output of the comparator K2 are connected in parallel and pulled up by a resistor R33, and the determination signal Ya1 is formed by each output of the comparators K1 and K2. If both the output of the comparator K1 and the output of the comparator K2 are at H level, the determination signal Ya1 becomes H level. If at least one of the output of the comparator K1 and the output of the comparator K2 is at L level, the determination signal Ya1 becomes L level.

(Signal generation circuit)
The control circuit 2 includes, as a signal generation circuit 22, an oscillation circuit J1, a transistor Q3, and capacitors C41 and C42. Transistor Q3 is a pnp type bipolar transistor. Capacitors C41 and C42 constitute a capacitive circuit of the present disclosure. Note that the transistor Q3 may be a semiconductor switching element other than a bipolar transistor, such as an FET.

The oscillation circuit J1 generates a triangular wave signal Ya2. The cycle of the triangular wave signal Ya2 is variable depending on the capacitance connected to the oscillation circuit J1. The smaller the capacitance connected to the oscillation circuit J1, the shorter the period of the triangular wave signal Ya2 (the higher the frequency of the triangular wave signal Ya2). In this embodiment, a capacitor C41 is always connected to the oscillation circuit J1, and the connection or disconnection of the capacitor C42 to the oscillation circuit J1 is switched by the transistor Q3. Transistor Q3 is turned on when determination signal Ya1 is at L level (at least one of the outputs of comparators K1 and K2 is at LH level). Transistor Q3 is turned off when determination signal Ya1 is at H level (both outputs of comparators K1 and K2 are at H level). When transistor Q3 is turned on, capacitor C42 is connected to oscillation circuit J1, and when transistor Q3 is turned off, capacitor C42 is disconnected from oscillation circuit J1. Therefore, the second period Tp2 (see FIG. 4) of the triangular wave signal Ya2 when the transistor Q3 is off is longer than the first period Tp1 (see FIG. 4) of the triangular wave signal Ya2 when the transistor Q3 is on. Becomes shorter.

Note that in this embodiment, the oscillation circuit J1 is included in the sequence control circuit 2a. The sequence control circuit 2a is, for example, an IC (Integrated Circuit) chip for power supply control.

(Power control circuit)
The control circuit 2 includes, as a power supply control circuit 21, a startup control section 211, a voltage step-up control circuit 2b, and a voltage step-down control circuit 2c. Note that in this embodiment, the activation control section 211 is included in the sequence control circuit 2a.

The activation control unit 211 receives the triangular wave signal Ya2 and counts the number of cycles of the triangular wave signal Ya2 as a count value. The startup control unit 211 executes a startup sequence based on the count value and generates a boost permission signal Ya3 and a target current signal Ya4. The boost permission signal Ya3 is a binary voltage signal that takes either an H level or an L level. The boost permission signal Ya3 goes to the L level when the boost operation of the boost chopper circuit 12 is permitted, and goes to the H level when the boost operation of the boost chopper circuit 12 is prohibited. Target current signal Ya4 is a voltage signal representing a target current value of load current Io, and the higher the voltage value of target current signal Ya4, the larger the target current value becomes. The voltage value of the target current signal Ya4 is set according to the dimming instruction value notified by the dimming signal Yd1.

The boost control circuit 2b includes a pulse setting section 212, an operational amplifier K3, a capacitor C51, and a transistor Q4. Transistor Q4 is an npn type bipolar transistor. Note that the transistor Q4 may be a semiconductor switching element other than a bipolar transistor, such as a MOSFET.

A DC reference voltage Vr2 is input to the positive input terminal of the operational amplifier K3, and a voltage detection signal Ys1 is input to the negative input terminal of the operational amplifier K3. A capacitor C51 is connected between the output terminal and the negative input terminal of the operational amplifier K3. Reference voltage Vr2 corresponds to the target voltage value of intermediate voltage V2. That is, the operational amplifier K3 outputs the difference between the detected value of the intermediate voltage V2 and the target voltage value as the error signal Ya5.

The pulse setting unit 212 generates a gate signal Yg1 for controlling on/off of the switching element Q1 so that the magnitude of the error signal Ya5 becomes 0, and outputs the gate signal Yg1. That is, the boost control circuit 2b performs feedback control on the boost chopper circuit 12 so that the intermediate voltage V2 matches the target voltage value.

The collector of transistor Q4 is connected to the output terminal of operational amplifier K3, and the emitter of transistor Q4 is connected to ground. The boost permission signal Ya3 output from the activation control section 211 is input to the base of the transistor Q4. Transistor Q4 is turned on when boost permission signal Ya3 is at H level, and turned off when boost permission signal Ya3 is at L level.

If the boost operation of the boost chopper circuit 12 is permitted, the boost permission signal Ya3 is at L level, so the transistor Q4 is turned off. In this case, the pulse setting unit 212 generates a gate signal Yg1 for controlling on/off of the switching element Q1 based on the error signal Ya5 generated by the operational amplifier K3.

If the boost operation of the boost chopper circuit 12 is prohibited, the boost permission signal Ya3 is at H level, so the transistor Q4 is turned on. As a result, the error signal Ya5 is maintained at 0V. In this case, since the error signal Ya5 is maintained at 0V, the pulse setting section 212 generates the gate signal Yg1 at a constant L level to maintain the switching element Q1 in the off state.

The step-down control circuit 2c includes a pulse setting section 213, an operational amplifier K4, and a capacitor C52.

The target current signal Ya4 is input to the positive input terminal of the operational amplifier K4, and the current detection signal Ys2 is input to the negative input terminal of the operational amplifier K4. A capacitor C52 is connected between the output terminal and the negative input terminal of the operational amplifier K4. That is, the operational amplifier K4 outputs the difference between the detected value of the load current Io and the target current value as the error signal Ya6.

The pulse setting unit 212 generates a gate signal Yg2 for controlling on/off of the switching element Q2 so that the magnitude of the error signal Ya6 becomes 0, and outputs the gate signal Yg2. That is, the step-down control circuit 2c performs feedback control on the step-down chopper circuit 13 so that the load current Io matches the target current value.

(1.4) Start-up sequence of lighting system The start-up sequence of lighting system A1 will be explained using FIGS. 3 and 4.

(1.4.1) Startup sequence during normal startup Figure 3 shows the startup sequence during normal startup.

Before time t0, the input voltage Vi is cut off and the lighting system A1 is stopped. At this time, charging voltages Vc1 and Vc2 are each 0V.

After the supply of the input voltage Vi is started at time t0, the determination circuit 23 determines at time t1 whether the stop time Ts from the previous cutoff of the input voltage Vi to time t1 is less than or equal to the time threshold Tr. do. The time threshold value Tr is the time required for the charging voltage Vc1 to decrease to the voltage threshold value Vr1 when the charging voltage Vc1 charged by steady lighting continues to discharge due to interruption of the input voltage Vi. If the outputs of the comparators K1 and K2 are at H level, the determination circuit 23 determines that the stop time Ts is equal to or less than the time threshold Tr. At time t1, both charging voltages Vc1 and Vc2 are less than voltage threshold Vr1. At this time, the output of the comparator K1 is at the L level, each output of the comparator K2 is at the H level, and the determination signal Ya1 is at the L level. That is, the determination circuit 23 determines that the stop time Ts is longer than the time threshold Tr (time t1). Therefore, the transistor Q3 is turned on, and the signal generation circuit 22 generates the triangular wave signal Ya2 of the first period Tp1.

The activation control unit 211 counts the number of cycles of the triangular wave signal Ya2 as a count value, and compares the count value with the first count threshold N1. At this point, the count value is less than the first count threshold N1, and the activation control unit 211 sets the boost permission signal Ya3 to H level and sets the target current signal Ya4 to 0V. That is, the startup control unit 211 turns on the transistor Q4 to prohibit the boost operation of the boost chopper circuit 12, and sets the target current value of the buck chopper circuit 13 to 0A. Therefore, the gate signals Yg1 and Yg2 maintain the L level, the load current Io maintains 0A, and the lighting load 3 is turned off. Note that the intermediate voltage V2 increases to almost the same voltage value as the rectified voltage V1.

Then, at time t2, the count value reaches the first count threshold N1. When the count value reaches the first count threshold N1, the activation control unit 211 sets the boost permission signal Ya3 to L level. That is, the startup control unit 211 turns off the transistor Q4 and allows the boost chopper circuit 12 to perform a boost operation. Therefore, the gate signal Yg1 alternately repeats H level and L level to switch the switching element Q1. As a result, the intermediate voltage V2 increases to the target voltage value.

The activation control unit 211 continues the counting process of counting the number of cycles of the triangular wave signal Ya2, and at time t3, the count value reaches the second count threshold N2. The second count threshold N2 is a value larger than the first count threshold N1. When the count value reaches the second count threshold N2, the activation control unit 211 sets the voltage value of the target current signal Ya4 to a value corresponding to the dimming lower limit of the lighting load 3. Therefore, the gate signal Yg2 alternately repeats H level and L level to switch the switching element Q2. As a result, the output voltage Vo increases from 0V, the load current Io increases to a value corresponding to the dimming lower limit, and the lighting load 3 lights up at the dimming lower limit.

Moreover, since the inductor current flows through the inductor L11 after time t3, the charging voltages Vc1 and Vc2 each increase, and each of the charging voltages Vc1 and Vc2 becomes equal to or higher than the voltage threshold Vr1. Therefore, even after time t3, the determination signal Ya1 becomes L level, and the signal generation circuit 22 generates the triangular wave signal Ya2 of the first period Tp1.

After lighting the lighting load 3 at the dimming lower limit for a predetermined time, the activation control unit 211 increases the voltage value of the target current signal Ya4 to a value corresponding to the dimming signal Yd1 at time t4. That is, after time t4, the activation control unit 211 sets the target current value of the step-down chopper circuit 13 according to the dimming signal Yd1. As a result, at time t5, the load current Io increases to the target current value according to the dimming signal Yd1. Therefore, the lighting load 3 is constantly lit at a dimming level according to the dimming signal Yd1.

At the time of normal startup described above, the period from time t1 to t2 is the first standby period T1a. The period from time t2 to time t3 is the second waiting period T2a. The period from time t3 to time t4 is the third waiting period T3a. The first standby period T1a is the time required for the external dimming device that generates the dimming signal Yd1 to stabilize. The second standby period T2a is the time required for stabilization of the intermediate voltage V2. The third standby period T3a is a time period during which the dimming level of the lighting load 3 is maintained at the dimming lower limit for soft start.

Further, the period from time t0 to time t5 is a startup period T10a from the start of supply of the input voltage Vi until the lighting load 3 is lit steadily.

(1.4.2) Start-up sequence at restart after instantaneous voltage sag When an instantaneous voltage sag occurs, the boost chopper circuit 12 stops boosting operation. However, the intermediate voltage V2, which is the voltage across the smoothing capacitor C2, does not decrease immediately but gradually decreases. Therefore, at the time of restart after an instantaneous voltage drop, the second standby period required for stabilizing the intermediate voltage V2 can be shortened compared to the time of normal startup.

Furthermore, when an instantaneous drop occurs, the DC smoothed voltage obtained by smoothing the dimming signal Yd1 does not drop immediately, but gradually drops. Therefore, when restarting after an instantaneous voltage drop, the first standby time required for stabilizing the external dimming device that generates the dimming signal Yd1 can be shortened compared to when starting normally.

Therefore, FIG. 4 shows the startup sequence when restarting after an instantaneous voltage drop.

Before time t10, the control circuit 2 lights the lighting load 3 steadily at a dimming level according to the dimming signal Yd1.

When an instantaneous voltage drop occurs at time t10 and the input voltage Vi decreases, the signal generation circuit 22 stops outputting the triangular wave signal Ya2 at time t11. Furthermore, at time t11, the startup control unit 211 sets the boost permission signal Ya3 to H level and sets the target current signal Ya4 to 0V. Therefore, gate signals Yg1 and Yg2 maintain the L level. As a result, the step-up chopper circuit 12 stops its step-up operation, and the step-down chopper circuit 13 stops its step-down operation. Therefore, the load current Io is maintained at 0A, and the lighting load 3 is turned off.

When an instantaneous sag occurs, the step-down chopper circuit 13 stops the step-down operation and no inductor current flows through the inductor L11, so the charging voltages Vc1 and Vc2 begin to decrease. At this time, the decreasing slope of charging voltage Vc1 is smaller than the decreasing slope of charging voltage Vc2. Therefore, the timing at which the charging voltage Vc2 becomes less than the voltage threshold value Vr1 is earlier than the timing at which the charging voltage Vc1 becomes less than the voltage threshold value Vr1. In this embodiment, the capacitance of the capacitor C31 and the resistance value of the resistor R31 are set so that the charging voltage Vc1 does not fall below the voltage threshold Vr1 within the assumed duration of the momentary sag.

Then, at time t12, after the voltage drop is resolved and the supply of input voltage Vi is resumed, at time t13, the determination circuit 23 determines whether the stop time Ts (times t11 to t13) is less than or equal to the time threshold Tr. judge. If the outputs of the comparators K1 and K2 are at H level, the determination circuit 23 determines that the stop time Ts is equal to or less than the time threshold Tr. At time t13, charging voltage Vc1 is greater than or equal to voltage threshold Vr1, and charging voltage Vc2 is less than voltage threshold Vr1. At this time, each output of the comparators K1 and K2 is at H level, and the determination signal is at H level. Therefore, the transistor Q3 is turned off, and the signal generation circuit 22 generates the triangular wave signal Ya2 of the second period Tp2. The activation control unit 211 counts the number of cycles of the triangular wave signal Ya2 as a count value, and compares the count value with the first count threshold N1. At this point, the count value is less than the first count threshold N1, and the activation control unit 211 sets the boost permission signal Ya3 to H level and sets the target current signal Ya4 to 0V. Therefore, since the gate signals Yg1 and Yg2 maintain the L level, the load current Io becomes 0A, and the lighting load 3 is turned off.

Then, at time t14, the count value reaches the first count threshold N1. When the count value reaches the first count threshold N1, the activation control unit 211 sets the boost permission signal Ya3 to L level. That is, the startup control unit 211 turns off the transistor Q4 and allows the boost chopper circuit 12 to perform a boost operation. Therefore, the gate signal Yg1 alternately repeats H level and L level to switch the switching element Q1. As a result, the intermediate voltage V2 increases to the target voltage value.

The activation control unit 211 continues the counting process of counting the number of cycles of the triangular wave signal Ya2, and at time t15, the count value reaches the second count threshold N2. When the count value reaches the second count threshold N2, the activation control unit 211 sets the voltage value of the target current signal Ya4 to a value corresponding to the dimming lower limit of the lighting load 3. Therefore, the gate signal Yg2 alternately repeats H level and L level to switch the switching element Q2. As a result, the load current Io increases to a value corresponding to the dimming lower limit, and the lighting load 3 is lit at the dimming lower limit.

Further, after time t15, since an inductor current flows through the inductor L11, the charging voltages Vc1 and Vc2 each increase, and each of the charging voltages Vc1 and Vc2 becomes equal to or higher than the voltage threshold Vr1. Therefore, after time t15, the determination signal Ya1 becomes L level, and the signal generation circuit 22 generates the triangular wave signal Ya2 of the first period Tp1.

After lighting the lighting load 3 at the dimming lower limit for a predetermined time, the activation control unit 211 increases the voltage value of the target current signal Ya4 to a value corresponding to the dimming signal Yd1 at time t16. That is, after time t16, the activation control unit 211 sets the target current value of the step-down chopper circuit 13 according to the dimming signal Yd1. As a result, the load current Io increases to the target current value according to the dimming signal Yd1 at time t17. Therefore, the lighting load 3 is constantly lit at a dimming level according to the dimming signal Yd1.

At the time of normal startup described above, the period from time t13 to time t14 is the first standby period T1b. The period from time t14 to time t15 is the second waiting period T2b. The period from time t15 to time t16 is the third waiting period T3a. The first standby period T1b is the time required for the external dimming device that generates the dimming signal Yd1 to stabilize. The second standby period T2b is the time required for the intermediate voltage V2 to stabilize. The third standby period T3b is a time period during which the dimming level of the lighting load 3 is maintained at the dimming lower limit for soft start.

Further, the period from time t12 to time t17 is a startup period T10b from the start of supply of the input voltage Vi until the lighting load 3 is lit steadily.

As described above, the signal generation circuit 22 generates the triangular wave signal Ya2 with the second period Tp2 shorter than the first period Tp1 when restarting after an instantaneous voltage sag. Therefore, when restarting after a power sag, the time required for the count value to reach the first count threshold N1 and the time required for the count value to reach the second count threshold N2 are shorter than during normal startup. Become. That is, the first waiting period T1b at the time of restarting after a voltage sag is shorter than the first waiting period T1a at the time of normal startup, and the second waiting period T2b at the time of restarting after a voltage sag is shorter than the first waiting period T1a at the time of normal startup. It is shorter than the second waiting period T2a in . Therefore, the startup period T10b at the time of restarting after the voltage drop is shorter than the startup period T10a at the time of normal startup. In other words, the time required for the lighting load 3 to turn on steadily at the time of restart from an instantaneous sag can be shortened.

(Second embodiment)
(2.1) Outline of Lighting System FIG. 5 shows a block configuration of a lighting system A2 for lighting the lighting load 3, as a lighting system of the second embodiment. Note that the same components as those in Embodiment 1 are denoted by the same reference numerals, and the description thereof will be omitted.

The lighting system A2 includes a power supply circuit 10 and a control circuit 20 as main components.

The power supply circuit 10 converts an AC input voltage Vi supplied from an external power supply 9 into a DC output voltage Vo. The power supply circuit 10 outputs an output voltage Vo from a pair of output terminals of the power supply circuit 10, and supplies a load current Io to the lighting load 3.

The control circuit 20 controls the power supply circuit 10 based on the dimming signal Yd1. The control circuit 2 controls the power supply circuit 1 so that the dimming level of the lighting load 3 matches the dimming instruction value.

(2.2) Power Supply Circuit The power supply circuit 10 includes a rectifier circuit 11, a SEPIC (Single Ended Primary Inductor Converter) circuit 14, and a current adjustment circuit 15. The SEPIC circuit 14 is a step-up/down chopper circuit that converts an AC input voltage Vi supplied from the external power supply 9 into a DC output voltage Vo. The current adjustment circuit 15 matches the magnitude of the load current Io with the target current value.

(2.2.1) SEPIC Circuit The SEPIC circuit 14 receives the rectified voltage V1 from the rectifier circuit 11 and outputs a DC output voltage Vo. SEPIC circuit 14 is controlled by control circuit 20.

Specifically, the SEPIC circuit 14 includes inductors L61, L62, capacitors C61, C62, smoothing capacitor C63, diode D61, and switching element Q5. The inductors L61 and L62 may be wound around the same core, or may be wound around different cores. A series circuit in which inductor L61, capacitor C62, diode D61, and smoothing capacitor C63 are connected in order from the positive pole is connected between the positive pole (high potential of rectified voltage V1) and negative pole (low potential of rectified voltage V1) of capacitor C61. has been done. A switching element Q5 is connected between the connection point between the inductor L61 and the capacitor C62 and the negative electrode of the capacitor C61. Switching element Q5 is an N-channel enhancement type MOSFET. The drain of the switching element Q5 is connected to the connection point between the inductor L61 and the capacitor C62, and the source of the switching element Q5 is connected to the negative electrode of the capacitor C61. Note that the switching element Q5 may be, for example, another semiconductor switching element such as a bipolar transistor in addition to the MOSFET.

An inductor L62 is connected between the connection point between the capacitor C62 and the diode D61 and the negative electrode of the capacitor C61. Then, the voltage across the smoothing capacitor C63 becomes the output voltage Vo. Note that the anode of the diode D61 is connected to the capacitor C62, and the cathode of the diode D61 is connected to the positive electrode of the smoothing capacitor C63.

Then, by turning on and off the switching element Q5, a step-up and step-up operation using the rectified voltage V1 as input is performed, and a DC output voltage Vo is generated across the smoothing capacitor C63.

Further, a winding Nb is magnetically coupled to the inductor L62, and a first end of the winding Nb is connected to the anode of the diode D23 and the anode of the diode D24. The second end of the winding Nb is connected to the negative electrode of the smoothing capacitor C63. A cathode of the diode D23 and a cathode of the diode D24 are connected to the control circuit 20. If the input voltage Vi is supplied to the lighting system A1, an inductor current flows through the inductor L62 due to switching of the switching element Q5. At this time, an induced voltage due to the inductor current is generated as an internal voltage of the power supply circuit 1 between both ends of the winding Nb. The induced voltage is half-wave rectified by each of the diodes D23 and D24, and the voltage at the cathode of the diode D23 is outputted to the control circuit 20 as the output detection signal Ys51, and the voltage at the cathode of the diode D24 is outputted to the control circuit 20 as the output detection signal Ys52.

(2.2.2) Current Adjustment Circuit A series circuit of the lighting load 3 and the current adjustment circuit 15 is connected between the output terminals of the SEPIC circuit 14. An output voltage Vo is applied to the series circuit of the lighting load 3 and the current adjustment circuit 15. The magnitude of the load current Io flowing through the lighting load 3 is controlled by the current adjustment circuit 15. The current adjustment circuit 15 can adjust the light output of the lighting load 3 by controlling the magnitude of the load current Io, and can turn on, turn off, and dim the lighting load 3.

The current adjustment circuit 15 includes a transistor Q6, an operational amplifier K5, a detection resistor R61, and resistors R62 and R63.

The transistor Q6 is an N-channel enhancement type MOSFET, and the drain of the transistor Q6 is connected to the cathode side of the lighting load 3. The source of transistor Q6 is connected to the first end of detection resistor R61. The second end of the detection resistor R61 is connected to the negative electrode of the smoothing capacitor C63. That is, a series circuit of the lighting load 3, the transistor Q6, and the detection resistor R61 is connected between the output terminals of the SEPIC circuit 14. Note that other transistors such as a bipolar transistor may be used as the transistor Q6.

A connection point between the source of the transistor Q6 and the detection resistor R61 is connected to the negative input terminal of the operational amplifier K5 via a resistor R62. Further, the positive input terminal of the operational amplifier K5 is connected to the control circuit 20, and receives the target current signal Ya12 from the control circuit 20. Further, a resistor R63 is connected between the output terminal and the negative input terminal of the operational amplifier K5. Furthermore, the output terminal of operational amplifier K5 is connected to the gate of transistor Q6. The operational amplifier K5 can adjust the magnitude of the load current Io flowing through the series circuit of the transistor Q6 and the detection resistor R61 by controlling the gate voltage of the transistor Q6.

That is, the current adjustment circuit 15 adjusts the load current Io to the target current value by controlling the transistor Q6 so that the voltage across the detection resistor R61 through which the load current Io flows matches the voltage value of the target current signal Ya12. .

Furthermore, in this embodiment, the voltage across the series circuit of the transistor Q6 and the detection resistor R61 (the voltage between the drain of the transistor Q6 and the negative electrode of the smoothing capacitor C63) is used as the feedback signal Ys4. Feedback signal Ys4 is input to control circuit 20. Control circuit 20 controls the switching operation of switching element Q5 based on feedback signal Ys4.

(2.3) Control Circuit The control circuit 20 determines whether the current startup is a normal startup or a restart after an instantaneous voltage sag, based on the output detection signals Ys51 and Ys52. Then, the control circuit 20 adjusts the dimming level of the lighting load 3 after the momentary sag by reducing the time required to turn on the lighting load 3 steadily when restarting after the momentary sag, compared to when starting normally. To quickly return to the same dimming level as before the voltage drop. That is, the control circuit 2 shortens the time required for the lighting load 3 to turn on steadily at the time of restart from an instantaneous voltage sag.

The configuration and operation of the control circuit 20 will be described in detail below.

(2.3.1) Block Configuration of Control Circuit The control circuit 2 includes a power supply control circuit 210, a signal generation circuit 22, and a determination circuit 23, as shown in FIG. Note that the signal generation circuit 22 and the determination circuit 23 are the same as those in the first embodiment, and a description thereof will be omitted.

Power supply control circuit 210 generates gate signal Yg5 based on feedback signal Ys4, and outputs gate signal Yg5 to the gate of switching element Q5. The gate signal Yg5 is a binary voltage signal that takes either an H level or an L level. When gate signal Yg5 is at H level, switching element Q5 is turned on, and when gate signal Yg5 is at L level, switching element Q5 is turned off. The power supply control circuit 21 adjusts the duty of the switching element Q5 by making variable the period during which the gate signal Yg5 is at H level with respect to the switching period. If the power supply control circuit 210 increases the output voltage Vo, it increases the duty of the switching element Q5. The power supply control circuit 210 reduces the duty of the switching element Q5 if the output voltage Vo is to be reduced.

Further, the power supply control circuit 210 generates a target current signal Ya12 based on the dimming signal Yd1, and outputs the target current signal Ya12 to the positive input terminal of the operational amplifier K5. That is, the power supply control circuit 210 controls the SEPIC circuit 14 to adjust the magnitude of the output voltage Vo, and controls the current adjustment circuit 15 to match the magnitude of the load current Io with the target current value. .

Then, the power supply control circuit 210 starts controlling the power supply circuit 10 when the number of cycles of the triangular wave signal Ya2 after startup reaches the count threshold.

(2.3.2) Circuit Configuration of Control Circuit FIG. 6 shows a specific circuit configuration of the control circuit 20. Note that the circuit configurations of the signal generation circuit 22 and the determination circuit 23 are the same as those in the first embodiment, and a description thereof will be omitted.

The control circuit 20 includes a startup control section 214 and a voltage control circuit 2e as a power supply control circuit 210. Note that in this embodiment, the activation control section 211 is included in the sequence control circuit 2d together with the oscillation circuit J1.

The activation control unit 214 receives the triangular wave signal Ya2 and counts the number of cycles of the triangular wave signal Ya2 as a count value. The startup control unit 211 executes a startup sequence based on the count value and generates an output permission signal Ya11 and a target current signal Ya12. The output permission signal Ya11 is a binary voltage signal that takes either an H level or an L level. The output permission signal Ya11 goes to the L level when the output operation of the SEPIC circuit 14 is permitted, and goes to the H level when the boosting operation of the SEPIC circuit 14 is prohibited. Target current signal Ya12 is an analog voltage signal representing a target current value of load current Io, and the higher the voltage value of target current signal Ya4, the larger the target current value becomes. The voltage value of the target current signal Ya12 is set according to the dimming instruction value notified by the dimming signal Yd1.

The voltage control circuit 2e includes a pulse setting section 215 and an error amplifier K11.

The error amplifier K11 outputs the difference between the feedback signal Ys4 and the DC reference voltage Vr11. The reference voltage Vr11 is preferably set to a value as low as possible while still allowing lighting of the lighting load 3, and is a value obtained by adding a certain value to the maximum value of the forward voltage of the lighting load 3. Therefore, the drain-source voltage of transistor Q6 is maintained at a value obtained by subtracting the voltage drop across detection resistor R61 from reference voltage Vr11, and power loss in transistor Q6 can be suppressed.

The pulse setting unit 215 generates a gate signal Yg5 for controlling on/off of the switching element Q5 so that the magnitude of the output of the error amplifier K11 becomes 0, and outputs the gate signal Yg5. That is, the voltage control circuit 2e performs feedback control on the SEPIC circuit 14 so that the feedback signal Ys4 matches the reference voltage Vr11.

If the output permission signal Ya11 is at the L level, the pulse setting unit 215 determines that the output operation of the SEPIC circuit 14 is permitted and generates a gate signal Yg5 that controls the switching element Q5 on and off. If the output permission signal Ya11 is at H level, the pulse setting unit 215 determines that the output operation of the SEPIC circuit 14 is prohibited and generates a gate signal Yg5 that maintains the switching element Q5 in the off state.

(2.4) Startup Sequence of Lighting System After startup, the startup control unit 214 counts the number of cycles of the triangular wave signal Ya2 as a count value, and compares the count value with the first count threshold N1. If the count value is less than the first count threshold N1, the activation control unit 214 sets the output permission signal Ya11 to H level and sets the target current signal Ya12 to 0V. That is, the startup control unit 214 prohibits the output operation of the SEPIC circuit 14 and sets the target current value of the current adjustment circuit 15 to 0A. Therefore, the load current Io is maintained at 0A, and the lighting load 3 is turned off.

Then, when the count value reaches the first count threshold N1, the activation control unit 214 sets the output permission signal Ya11 to L level. That is, the activation control unit 214 permits the output operation of the SEPIC circuit 14. Therefore, the gate signal Yg5 alternately repeats H level and L level to switch the switching element Q5. As a result, the output voltage Vo increases.

When the count value reaches the second count threshold N2, the activation control unit 214 sets the voltage value of the target current signal Ya12 to a value corresponding to the dimming lower limit of the lighting load 3. The load current Io increases to a value corresponding to the dimming lower limit, and the lighting load 3 is lit at the dimming lower limit.

After lighting the lighting load 3 at the dimming lower limit for a predetermined time, the activation control unit 214 increases the voltage value of the target current signal Ya12 to a value corresponding to the dimming signal Yd1. As a result, the load current Io increases to the target current value according to the dimming signal Yd1. Therefore, the lighting load 3 is constantly lit at a dimming level according to the dimming signal Yd1.

Then, as in the first embodiment, the signal generation circuit 22 generates a triangular wave signal Ya2 having a second period Tp2 shorter than the first period Tp1 at the time of restart after an instantaneous voltage drop. Therefore, when restarting after a power sag, the time required for the count value to reach the first count threshold N1 and the time required for the count value to reach the second count threshold N2 are shorter than during normal startup. Become. Therefore, the startup period at the time of restart after an instantaneous voltage drop is shorter than the startup period at the time of normal startup. In other words, the time required for the lighting load 3 to turn on steadily at the time of restart from an instantaneous sag can be shortened.

Note that, in addition to the SEPIC circuit, either a CUK circuit or a ZETA circuit may be used as the buck-boost chopper circuit.

(Third embodiment)
FIG. 7 is a plan view showing a printed wiring board 7 on which a plurality of circuit components included in the lighting system A1 are mounted. The plurality of circuit components include a circuit component X11 included in the power supply circuit 1 and a circuit component X12 included in the control circuit 2.

The printed wiring board 7 has a long rectangular plate (flat plate) shape, and has a first end 71 in the longitudinal direction and a second end 72 in the longitudinal direction. Mounted on the first end 71 of the printed wiring board 7 is an input connector (input terminal) CN1 having a pair of terminals to which an input voltage Vi is supplied. Mounted on the second end 72 of the printed wiring board 7 is an output connector (output terminal) CN2 having a pair of terminals from which an output voltage Vo is output.

The circuit component X11 is a circuit component that constitutes the power supply circuit 10, and a plurality of circuit components X11 are mounted so as to be lined up from the first end 71 toward the second end 72 along the power transmission direction.

The printed wiring board 7 has an output region Z1 extending from approximately the center in the longitudinal direction to the second end 72. In the output region Z1, among the plurality of circuit components X11, an inductor L11 and a winding Na (see FIG. 1), which are circuit components X11 constituting the output stage of the power supply circuit 10, are mounted. A circuit component X12 constituting the control circuit 2 is also mounted in the output area Z1.

Therefore, the path of the output detection signals Ys31 and Ys32 from the winding Na to the control circuit 2 can be shortened, and the routing of the path can be simplified. As a result, the printed wiring board 7 can be made smaller. Moreover, the paths of the output detection signals Ys31 and Ys32 are low voltage paths, and the high voltage path in the printed wiring board 7 can be reduced.

(Fourth embodiment)
8A and 8B show lighting fixture B1. The lighting fixture B1 includes a lighting system A1, a lighting load 3, and a fixture body 8.

The instrument main body 8 has a housing 81 and a cover 82. The housing 81 is made of a metal material and is shaped like a box with an open front. The cover 82 is made of a translucent material such as quartz glass or polycarbonate resin, and is formed into a flat plate shape that matches the outer shape of the opening of the housing 81 . The cover 82 is attached to the housing 81 by a pair of hinges 83 so as to be rotatable between a closed position where the front opening of the housing 81 is closed and an open position where the front opening is opened. Furthermore, a pair of stops 84 are provided at the edge of the housing 81. That is, when the cover 82 is in the closed position, the pair of fasteners 84 are caught on the free end side of the cover 82, thereby fixing the cover 82 in the closed position.

Furthermore, two mounting fittings 85 are provided on the outer bottom surface of the instrument main body 8 (casing 81) so as to protrude outward for attachment to a tunnel wall or the like. By screwing these fittings 85 to the tunnel wall, etc., the instrument main body 8 is fixed to the tunnel wall, etc.

The lighting system A1 and the lighting load 3 are fixed to the inner bottom surface of the housing 81. Furthermore, a terminal block 86 is attached to the inner bottom surface of the housing 81. The lighting system A1 is supplied with an input voltage Vi via the terminal block 86.

Note that a lighting system A2 may be housed inside the appliance main body 8 instead of the lighting system A1.

(Modified example)
The control circuits 2 and 20 in each of the embodiments described above may include a computer system. In this case, the computer system mainly includes a processor and memory as hardware. The functions of the control circuits 2 and 20 in the present disclosure are realized by a processor executing a program recorded in the memory of the computer system. The program may be pre-recorded in the computer system's memory, or may be provided via a telecommunications line, or on a non-transitory storage medium readable by the computer system, such as a memory card, optical disc, or hard disk drive. It may be recorded and provided. A processor of a computer system is composed of one or more electronic circuits including a semiconductor integrated circuit (IC) or a large-scale integrated circuit (LSI). The plurality of electronic circuits may be integrated into one chip, or may be provided in a distributed manner over a plurality of chips. A plurality of chips may be integrated into one device, or may be distributed and provided in a plurality of devices.

Furthermore, the control circuits 2 and 20 are not limited to computer systems, and may be, for example, ASICs (Application Specific Integrated Circuits), FPGAs (Field Programmable Gate Arrays), control ICs (Integrated Circuits), or the like.

(summary)
The lighting system (A1, A2) of the first aspect according to the above-described embodiment includes a power supply circuit (1, 10) and a control circuit (2, 20). The power supply circuits (1, 10) start up when supplied with an input voltage (Vi) from an external power supply (9), convert the input voltage (Vi) to a voltage after starting up, and convert the output voltage (Vo) into a lighting load (Vo). 3). The control circuit (2, 20) controls the power supply circuit (1, 10). The control circuit (2, 20) includes a signal generation circuit (22), a power supply control circuit (21, 210), and a determination circuit (23). The signal generation circuit (22) generates a periodically changing signal (Ya2). The power supply control circuit (21, 210) counts the number of cycles of the signal (Ya2) after startup, and when the count value reaches the count threshold (N1, N2), starts controlling the power supply circuit (1, 10). . The determination circuit (23) determines whether the stop time (Ts), which is the time from when the power supply circuit (1, 10) stops until it starts, is less than or equal to a time threshold (Tr). If the stop time (Ts) is longer than the time threshold (Tr), the signal generation circuit (22) sets the period of the signal (Ya2) to the first period (Tp1), and if the stop time (Ts) is less than or equal to the time threshold (Tr). If so, the period of the signal (Ya2) is set to a second period (Tp2) shorter than the first period (Tp1).

Therefore, the lighting system (A1, A2) can shorten the time required until the lighting load (3) is steadily lit upon restart from an instantaneous sag.

In the lighting system (A1, A2) of the second aspect according to the above-described embodiment, in the first aspect, the determination circuit (23) includes a first time constant circuit (CR1) and a second time constant circuit (CR2). ), a first comparison circuit (K1), and a second comparison circuit (K2). The first time constant circuit (CR1) is charged by the internal voltage of the power supply circuit (1, 10) and discharged at the first time constant. The second time constant circuit (CR2) is charged by the internal voltage and discharged with a second time constant shorter than the first time constant. The first comparison circuit (K1) compares the charging voltage (Vc1) of the first time constant circuit (CR1) with a voltage threshold (Vr1). The second comparison circuit (K2) compares the charging voltage (Vc2) of the second time constant circuit (CR2) with a voltage threshold (Vr1).

Therefore, the lighting systems (A1, A2) can measure the stop time (Ts) with a simple configuration.

In the lighting system (A1, A2) of the third aspect according to the above-described embodiment, in the second aspect, the determination circuit (23) determines whether the first time constant circuit ( The charging voltage (Vc1) of the second time constant circuit (CR2) is equal to or higher than the voltage threshold (Vr1) in the comparison result of the second comparison circuit (K2). ), it is preferable to determine that the stop time (Ts) is equal to or less than the time threshold (Tr).

Therefore, the lighting systems (A1, A2) can determine the stop time (Ts) with a simple configuration.

In the lighting system (A1, A2) of the fourth aspect according to the above-described embodiment, in the second or third aspect, the determination circuit (23) determines the first time in the comparison result of the first comparison circuit (K1). If the charging voltage (Vc1) of the constant circuit (CR1) is less than the voltage threshold (Vr1), it is preferable to determine that the stop time (Ts) is longer than the time threshold (Tr).

Therefore, the lighting system (A1, A2) can easily determine the stop time (Ts).

In the lighting system (A1, A2) of the fifth aspect according to the above-described embodiment, in any one of the first to fourth aspects, the signal generation circuit (22) is a capacitive circuit (22) having a capacitance ( C41, C42). The signal generating circuit (22) switches the period of the signal (Ya2) to the first period (Tp1) or the second period (Tp2) by changing the capacitance.

Therefore, the lighting system (A1, A2) can specifically realize a configuration that switches the cycle of the signal (Ya2).

In the lighting system (A1) of the sixth aspect according to the above-described embodiment, in any one of the first to fifth aspects, the power supply circuit (1) includes a step-up chopper circuit (12) and a step-down chopper circuit. (13) It is preferable to have the following. The boost chopper circuit (12) generates an intermediate voltage (V2) by boosting the input voltage (Vi). The step-down chopper circuit (13) steps down the intermediate voltage (V2) to the output voltage (Vo). The power supply control circuit (21) uses a first count threshold (N1) and a second count threshold (N2) larger than the first count threshold (N1) as count thresholds. The power supply control circuit (21) starts controlling the boost chopper circuit (12) when the number of cycles after startup reaches the first count threshold (N1). The power supply control circuit (21) starts controlling the step-down chopper circuit (13) when the number of cycles after startup reaches the second count threshold (N2).

Therefore, the lighting system (A1) has a configuration including a step-up chopper circuit (12) and a step-down chopper circuit (13), and the time required for the lighting load (3) to steadily turn on when restarting from an instantaneous sag. can be shortened.

In the lighting system (A2) of the seventh aspect according to the above-described embodiment, in any one of the first to fifth aspects, the power supply circuit (10) includes a buck-boost chopper circuit (14) and a current adjustment It is preferable to have a circuit (15). The buck-boost chopper circuit (14) converts the input voltage (Vi) into an output voltage (Vo). The current adjustment circuit (15) adjusts the load current (Io) flowing through the lighting load (3). The power supply control circuit (210) uses a first count threshold (N1) and a second count threshold (N2) larger than the first count threshold (N1) as count thresholds. The power supply control circuit (210) starts controlling the buck-boost chopper circuit (14) when the number of cycles after startup reaches the first count threshold (N1). The power supply control circuit (210) starts controlling the current adjustment circuit (15) when the number of cycles after startup reaches the second count threshold (N2).

Therefore, in the lighting system (A2), in a configuration including a buck-boost chopper circuit (14) and a current adjustment circuit (15), it is necessary to turn on the lighting load (3) steadily when restarting from an instantaneous sag. It can save time.

In any one of the first to seventh aspects, the lighting system (A1) of the eighth aspect according to the above-described embodiment includes a plurality of lighting systems constituting each of the power supply circuit (1) and the control circuit (2). It is preferable to include a printed wiring board (7) on which circuit components (X11, X12) are mounted.

The printed wiring board (7) is formed into a long flat plate shape. An input terminal (CN1) to which the input voltage (Vi) is input is provided at the first end (71) in the longitudinal direction of the printed wiring board (7), and an output terminal (CN2) to which the output voltage (Vo) is output is provided. It is provided at the second longitudinal end (72) of the printed wiring board (7). At least two circuit components (X11) constituting the power supply circuit (1) among the plurality of circuit components (X11, It is implemented so that it is lined up towards the front. Among the plurality of circuit components (X11, ).

Therefore, in the lighting system (A1), the printed wiring board 7 can be made smaller.

The lighting fixture of the ninth aspect according to the above-described embodiment (B1 is the lighting system (A1, A2) of any one of the first to eighth aspects and the lighting turned on by the lighting system (A1, A2) It includes a load (3) and a fixture body (8) that supports at least the lighting load (3).

Therefore, the lighting fixture (B1) can shorten the time required for the lighting load (3) to turn on steadily when restarting from an instantaneous voltage sag.

Furthermore, the above-described embodiments and modifications are merely examples. Therefore, the present invention is not limited to the above-described embodiments and modified examples, and even if the present invention is not limited to the above-described embodiments and modified examples, as long as it does not deviate from the technical idea of the present invention, the design Of course, various changes can be made depending on the situation.

A1, A2 Lighting system 1, 10 Power supply circuit 12 Boost chopper circuit 13 Buck chopper circuit 14 Buck-boost chopper circuit 15 Current adjustment circuit 2, 20 Control circuit 21, 210 Power supply control circuit 22 Signal generation circuit 23 Judgment circuit 3 Lighting load 7 Print Wiring board 71 First end 72 Second end 8 Apparatus body 9 External power supply CR1 First time constant circuit CR2 Second time constant circuit K1 First comparison circuit K2 Second comparison circuit C41, C42 Capacitance circuit X11, X12 Circuit components CN1 Input Connector (input terminal)
CN2 output connector (output terminal)
Vi Input voltage Vo Output voltage V2 Intermediate voltage Vc1 Charging voltage Vc2 Charging voltage Vr1 Voltage threshold Ya2 Triangular wave signal (signal)
N1 1st count threshold (count threshold)
N2 2nd count threshold (count threshold)
Ts Stop time Tr Time threshold Tp1 1st period Tp2 2nd period

Claims (9)

a power supply circuit that starts when an input voltage is supplied from an external power supply, converts the input voltage to a voltage after starting, and supplies the output voltage to the lighting load;
A control circuit that controls the power supply circuit,
The control circuit includes:
a signal generation circuit that generates a periodically changing signal;
a power supply control circuit that starts controlling the power supply circuit when the number of cycles of the signal after the activation reaches a count threshold;
a determination circuit that determines whether a stop time, which is the time from when the power supply circuit stops until it starts, is less than or equal to a time threshold;
The signal generation circuit includes:
If the stop time is longer than a time threshold, the period of the signal is a first period;
If the stop time is equal to or less than the time threshold, the period of the signal is set to a second period shorter than the first period. The lighting system. The determination circuit is
a first time constant circuit that is charged by the internal voltage of the power supply circuit and discharged at a first time constant;
a second time constant circuit that is charged by the internal voltage and discharged with a second time constant that is smaller than the first time constant;
a first comparison circuit that compares the charging voltage of the first time constant circuit with a voltage threshold;
The lighting system according to claim 1, further comprising a second comparison circuit that compares the charging voltage of the second time constant circuit and the voltage threshold. The determination circuit determines that the charging voltage of the first time constant circuit is equal to or higher than the voltage threshold in the comparison result of the first comparison circuit, and that the charging voltage of the second time constant circuit is higher than or equal to the voltage threshold in the comparison result of the second comparison circuit. The lighting system according to claim 2, wherein if the voltage is less than the voltage threshold, it is determined that the stop time is less than or equal to the time threshold. The lighting according to claim 2 or 3, wherein the determination circuit determines that the stop time is longer than the time threshold if the charging voltage of the first time constant circuit is less than the voltage threshold in the comparison result of the first comparison circuit. system. Any one of claims 1 to 4, wherein the signal generation circuit includes a capacitance circuit having a capacitance, and switches the period of the signal to the first period or the second period by changing the capacitance. One lighting system. The power supply circuit is
a boost chopper circuit that generates an intermediate voltage by boosting the input voltage;
a step-down chopper circuit that steps down the intermediate voltage to the output voltage;
The power supply control circuit includes:
Using a first count threshold and a second count threshold larger than the first count threshold as the count threshold,
When the number of cycles after the start-up reaches the first count threshold, control of the boost chopper circuit is started;
The lighting system according to any one of claims 1 to 5, wherein control of the step-down chopper circuit is started when the number of cycles after the start-up reaches the second count threshold. The power supply circuit is
a buck-boost chopper circuit that converts the input voltage to the output voltage;
a current adjustment circuit that adjusts the load current flowing through the lighting load;
The power supply control circuit includes:
Using a first count threshold and a second count threshold larger than the first count threshold as the count threshold,
When the number of cycles after the start-up reaches the first count threshold, control of the buck-boost chopper circuit is started;
The lighting system according to any one of claims 1 to 5, wherein control of the current adjustment circuit is started when the number of cycles after the start-up reaches the second count threshold. comprising a printed wiring board on which a plurality of circuit components constituting each of the power supply circuit and the control circuit are mounted;
The printed wiring board is formed in a long flat plate shape,
An input terminal to which the input voltage is input is provided at a first end in the longitudinal direction of the printed wiring board, an output terminal to which the output voltage is output is provided at a second end in the longitudinal direction of the printed wiring board,
At least two circuit components constituting the power supply circuit among the plurality of circuit components are mounted so as to be lined up from the first end toward the second end of the printed wiring board,
Any one of claims 1 to 7, wherein at least one circuit component forming the determination circuit among the plurality of circuit components is mounted on the printed wiring board at a position closer to the second end than to the first end. or one lighting system. A lighting system according to any one of claims 1 to 8,
a lighting load lit by the lighting system;
A lighting fixture, comprising: a fixture body that supports at least the lighting load.

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