JP2019004576A - Power supply device - Google Patents

Abstract

To provide a technique for preventing excess starting current when power is turned on again.SOLUTION: A power supply device 100 includes: a rectification section 104 generating input voltage by rectifying AC voltage of an AC power source 102; a PFC control section 110 for generating output voltage by power-factor-improvement controlling the input voltage; a DC/DC converter 118 for outputting DC voltage by converting the output voltage of the PFC control section 110; a starting circuit 120 for applying starting power to the PFC control section 110; and a starting voltage control section (path from a point P1 to a starting resistor R4) enabling the application of starting voltage to the PFC control section 110 by the starting circuit 120 when the input voltage is applied, and on the other hand, restraining the application of the starting voltage by the starting circuit 120 when the input voltage is not applied.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power supply apparatus that outputs a DC voltage converted from an AC voltage.

  With respect to this type of power supply device, a prior art of an LED power supply device including a DC / DC converter that outputs a DC voltage converted from an AC voltage to an LED of a load is known (for example, see Patent Document 1).

  In this prior art, the AC voltage is full-wave rectified by a rectifier circuit, and the DC voltage boosted by PWM control of the switching element of the PFC circuit is output to a buck converter circuit (DC / DC converter). The output voltage is charged in the capacitor before the buck converter circuit, and the buck converter circuit transforms the voltage of the capacitor by PWM control of the switching element, and outputs a DC voltage to the load. The driving state of each switching element of the PFC circuit and the buck converter circuit is controlled by each control IC, and the PFC circuit and the buck converter circuit drive the switching element according to the PWM control signal from the control IC to output voltage. Alternatively, the output current is controlled. A control power supply circuit is connected to the control IC, and a control power supply voltage of about 15 V can be extracted from the capacitor of the control power supply circuit.

JP 2017-46535 A

  In the above prior art, even if the application of the input voltage is momentarily stopped (or the voltage is lowered) at the time of a power failure, the control IC of the PFC circuit is driven by the control power supply voltage charged in the capacitor. The PFC circuit and the buck converter circuit continue to operate in the same manner as in the steady state. However, the voltage fed back to the PFC_V terminal when the input voltage is momentarily stopped is the voltage of the capacitor C3 and is lower than the output voltage to be controlled by the PFC circuit in the steady state, so that the gate of the PFC_drive (DR) terminal The signal tries to operate with the ON width widened in the direction of increasing the output voltage. If the power is turned on again (return of power interruption) in this state, there is a problem that an excessive start-up current is generated when the input voltage is applied.

  Therefore, the present invention provides a technique for preventing the starting current from becoming excessive when the power is turned on again.

  In order to solve the above problems, the present invention employs the following solutions.

  The power supply device of the present invention is configured to stop the operation of the PFC control unit when the input voltage is not applied in the configuration having the PFC control unit and the DC / DC converter. Specifically, for a startup circuit that applies a startup voltage to the PFC control unit using an internal voltage generated between the rectification unit and the DC / DC converter, the startup voltage control is performed when the input voltage is applied. While enabling the application of the starting voltage to the PFC control unit by, the application of the starting voltage to the PFC control unit is suppressed when the input voltage is not applied.

[Measures for primary starting current]
Thereby, for example, while the application of the input voltage is stopped by an instantaneous stop, the voltage (starting current) supplied to the PFC control unit can be eliminated, and the operation of the PFC control unit can be stopped reliably. After the power is turned on again, the PFC control unit starts operation from the start (stopped state) including the ON width of the gate drive by PWM control, so the peak of the input current (primary start-up current) is excessive. Can be suppressed.

[Secondary starting current countermeasures]
Furthermore, the present invention also has a solution based on unique knowledge.
That is, the start-up current peak at the time of re-input as described above may not only occur as the primary start-up current when the input voltage is re-applied, but may also occur as a secondary start-up current later. This is because the output voltage temporarily overshoots in the PFC controller when the power is turned on again, and the OVP (overvoltage protection) function is activated and the gate drive is temporarily stopped. However, the DC / DC converter continues to operate during this time. Therefore, when the output voltage drops to the release voltage of the OVP function, the DC / DC converter itself becomes an excessive load, greatly reducing the output voltage (the voltage charged in the electrolytic capacitor before the DC / DC converter). As a result, the ON width of the gate drive at the time of restarting is excessively widened.

  For this reason, this invention has the structure of an output current control part as a countermeasure against a secondary starting current. The output current control unit controls the output current from the DC / DC converter to the load to be lower than the steady value at the start of generation of the output voltage by the PFC control unit, and gradually increases the output current toward the steady value as time elapses. I do. Thereby, the output voltage of a PFC control part can be started in a light load state.

  In other words, by starting the output voltage of the PFC control unit in a light load state, the output voltage while the PFC control unit is temporarily stopped by the OVP function is obtained when the DC / DC converter is started at the rated power. In comparison, the drop is gentle, and a significant drop in output voltage can be suppressed. Further, even when the PFC control unit is restarted after the OVP is released, the output power can be started with the gate drive ON width suppressed by maintaining the light load state. Thereby, it can suppress that the secondary starting current at the time of the re-operation of a PFC control part becomes excessive.

  In addition, the present invention discloses the following aspects as countermeasures for the primary starting current.

[First embodiment]
When the circuit configuration of the power supply apparatus includes an electrolytic capacitor in the previous stage of the DC / DC converter, the start-up voltage control is connected to a path where the voltage from the electrolytic capacitor is not applied when the input voltage is not applied.

  According to the above aspect, since the voltage from the electrolytic capacitor is not applied to the starting circuit while the application of the input voltage is stopped due to the instantaneous stop, the starting voltage necessary for starting the PFC control unit is not applied, The PFC control unit can be stopped reliably.

[Second embodiment]
The starting voltage control unit detects the input voltage by the input voltage detecting unit, and when the application is not detected, the starting circuit is stopped by the ON / OFF circuit.

  According to the above aspect, since the start circuit is stopped while the input voltage is not applied due to the instantaneous stop, the start voltage necessary for starting the PFC control unit is not applied, and the PFC control unit is reliably Can be stopped.

  According to the present invention, it is possible to prevent the starting current from becoming excessive when the power is turned on again.

It is a circuit diagram showing roughly the composition of the power unit of a 1st embodiment. It is a block diagram showing roughly the composition of the power unit of a 1st embodiment. It is a circuit diagram which shows roughly the structure of the power supply device used as a comparative example. It is a block diagram which shows roughly the structure of the power supply device used as a comparative example. It is a figure which shows the various changes at the time of the power interruption of a power supply device of a comparative example, and re-inputting. FIG. 6 is a diagram showing temporal changes in input voltage and input current on the same time axis as in FIG. 5. It is a figure which shows the gate drive waveform of the PFC control circuit observed in a comparative example. It is a figure which shows the various changes at the time of the power interruption of the power supply device of 1st Embodiment having occurred, and restarting. FIG. 9 is a diagram illustrating temporal changes in input voltage and input current on the same time axis as in FIG. 8. It is a figure which shows the gate drive waveform of the PFC control circuit observed in 1st Embodiment. It is a circuit diagram which shows roughly the structure of the power supply device of 2nd Embodiment. It is a block diagram which shows roughly the structure of the power supply device of 2nd Embodiment. It is a flowchart which shows the example of a procedure of the main control process which the output current control part of a DC / DC converter performs.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Hereinafter, an embodiment in which the power supply device is configured as a constant current type LED lighting power source will be described as an example. However, the present invention is not limited to such an embodiment.

[First Embodiment]
FIG. 1 is a circuit diagram schematically showing the configuration of the power supply apparatus 100. In the circuit diagram of FIG. 1, some electrical configurations are simplified as block elements.

  The power supply device 100 is connected to an AC power source 102 (for example, AC 200V) as an external power source, and has an internal configuration such as a rectifying unit 104, an inrush current prevention circuit 106, a ripple filter 108, a PFC control unit 110, and an output voltage detection unit. 116, a DC / DC converter 118, and the like. The power supply apparatus 100 includes a PFC control circuit 114 as an internal element of the PFC control unit 110, and also includes an activation circuit 120, an input voltage detection circuit 122, and the like as accompanying elements. The power supply apparatus 100 converts the AC power supply 102 and supplies a DC voltage subjected to constant current control to the load 121. The load 121 is, for example, an LED lighting device, and a commercial power source and a battery-driven inverter power source can be used as the AC power source 102. In this case, the power supply apparatus 100 can be suitably implemented as an uninterruptible power supply facility of an inverter suspension standby system (instantaneous interruption time of 250 ms or less).

  The function of the power supply apparatus 100 will be schematically described. First, the input AC voltage of the AC power supply 102 is full-wave rectified by the rectification unit 104 and becomes an input voltage (DC voltage) through the inrush current prevention circuit 106. After the input voltage passes through the ripple filter 108, the power factor correction is controlled by the PFC control unit 110 to become an output voltage. The output voltage is detected by the output voltage detector 116 and input to the PFC control circuit 114 as a feedback signal. In response to this, the PFC control circuit 114 outputs a gate drive signal, and appropriately controls the output voltage by switching the switching element Q1 (PWM control). The output voltage is charged and smoothed by the electrolytic capacitor C3, and is output to the load 121 as a DC voltage that is step-down and constant current controlled by the DC / DC converter 118.

  The startup circuit 120 applies the startup voltage to the Vcc terminal of the PFC control circuit 114 while the input voltage is applied to the startup resistor R4. The input voltage detection circuit 122 inputs an ON signal to the DC / DC converter 118 while the input voltage is applied to the detection resistors R6 and R7. In the first embodiment, the start-up circuit 120 and the switching circuit 122 are connected to the input voltage before the ripple filter 108 (P1 point).

  FIG. 2 is a block diagram schematically showing the configuration of the power supply device 100 of the first embodiment. 2, the same components as those shown in FIG. 1 are denoted by the same reference numerals.

  As described above, the processing flow inside the power supply device 100 continues from the rectifying unit 104 to the inrush current prevention circuit 106, the ripple filter 108, the PFC control unit 110, and the DC / DC converter 118. Along with this, the output voltage detection unit 116, the activation circuit 120, the input voltage detection circuit 122, and the like function. The PFC control unit 110 performs switching (PWM control) by the internal PFC control circuit 114 to control the output voltage, and the DC / DC converter 118 performs switching (PWM control) by the internal output current control unit 126. Control the output voltage (constant current control).

[Starting voltage controller]
Here, as described above, in the first embodiment, the starting circuit 120 is connected to the input voltage at the previous stage (P1 point) of the ripple filter 108. For this reason, when the power supply from the AC power supply 102 is momentarily interrupted (instantaneous interruption), the input voltage is not applied (in FIG. 1, the input voltage is not applied to the activation resistor R4). The application of the starting voltage to the unit 110 is suppressed (stopped). Therefore, while the input voltage is stopped due to an instantaneous stop, the voltage (starting current) supplied to the PFC control unit 110 can be eliminated and the PFC control unit 110 can be stopped.

  In view of the same concept as described above, the starting resistor R4 may be connected to the bridge diode (rectifier 104) side of the inductor L2 of the PFC controller 110 in the circuit configuration of FIG. Therefore, the starting circuit 120 may be connected to the input voltage at the subsequent stage (point P2) of the ripple filter 108. Even in this case, it is possible to adopt a configuration in which the starting voltage is not applied to the PFC control unit 110 while the input voltage is not applied.

[Contrast with comparative example]
The usefulness of the first embodiment shown in FIG. 1 and FIG. 2 will become clear by comparison with the following comparative example.

  FIG. 3 is a circuit diagram schematically showing a configuration of a power supply device 300 as a comparative example. Similarly, FIG. 4 is a block diagram schematically showing a configuration of a power supply device 300 as a comparative example. In FIG. 3 and FIG. 4, the same components as those in the first embodiment are denoted by common reference numerals, and redundant description is omitted.

[Configuration of Comparative Example]
The power supply device 300 according to the comparative example is different from the power supply device 100 according to the first embodiment in that the activation circuit 120 is connected to the output voltage at the subsequent stage (point P3) of the PFC control unit 110. In this case, while the input voltage is being applied, the output voltage is applied to the starting resistor R4 of the starting circuit 120, so that the PFC control unit 110 can operate normally.

[When instantaneous interruption occurs]
On the other hand, in the comparative example, when an instantaneous stop of, for example, 250 ms occurs in the AC power supply 102, the input voltage is not applied during the stop, so that the charge (voltage) charged in the electrolytic capacitor C3 starts to be discharged. At this time, since the starting resistor R4 of the starting circuit 120 is connected to the cathode side (point P3) of the diode D1, the charge of the capacitor C3 is also discharged by the starting resistor R4. Then, the PFC control unit 110 continues to operate until it becomes equal to or less than the off threshold voltage (voltage threshold at which the operation is turned off) of the PFC control circuit 114 (control IC) through the starting resistor R4.

In an instantaneous stop of about 250 ms, the discharge of the electrolytic capacitor C3 does not stop due to the relationship with the capacity, and the start-up voltage applied from the start-up circuit 120 does not drop below the off-threshold voltage of the PFC control circuit 114. The control unit 110 continues to operate. On the other hand, since the voltage detected by the output voltage detection unit 116 as the output voltage of the PFC control unit 110 during the instantaneous stop is the voltage of the electrolytic capacitor C3, the output that the PFC control unit 110 is trying to control at this level of voltage. Compared to voltage, it is overwhelmingly lower.
[Generation of primary starting current]

  Then, the ON drive width of the gate drive signal output from the PFC control circuit 114 during the instantaneous stop is wider than usual in order to increase the output voltage. If the AC power supply 102 is turned on again (inverter power supply) before the operation of the PFC control unit 110 stops in this state, an excessive primary starting current is generated when the input voltage is reapplied.

  FIG. 5 is a diagram illustrating various changes in the case where an instantaneous power interruption and reactivation occurs in the power supply apparatus 300 of the comparative example. Among these, (A) in FIG. 5 shows the state at that time, and (B) in FIG. 5 shows the input current of the DC / DC converter 118. Further, “PFC voltage” in FIG. 5C indicates the charge (voltage) of the electrolytic capacitor C3, and FIG. 5D indicates the output current of the DC / DC converter 118.

[Before time t1]
Prior to time t1, the state shown in FIG. 5A is “steady”, and the input current shown in FIG. 5B and the PFC voltage shown in FIG. 5C are both rated values (Peak). -Peak). Therefore, the output current shown in (D) of FIG. 5 is constant current controlled to the rated value.

[Time t1 to Time t2]
When the AC power supply 102 is interrupted at time t1, the state shown in FIG. 5A is “power failure” and the input current shown in FIG. 5B is stopped. The PFC voltage shown in FIG. 5 (C) decreases due to the discharge of the electrolytic capacitor C3, but the discharge does not end in the instantaneous stop (250 ms or less) from time t1 to time t2, and the PFC control unit 110 operates even in a power failure state. Keep doing. On the other hand, the output current of (D) in FIG.

[Time t2]
When the AC power supply 102 is switched to the inverter power supply at time t2, the state shown in FIG. 5A is “inverter drive”. As already described, in the comparative example, the PFC control unit 110 continues to operate even during the instantaneous stop, but the value detected as the output voltage is the PFC voltage shown in FIG. 5C, which is the PFC control. Since the unit 110 is lower than the target output voltage to be controlled in the steady state, the ON width of the gate drive signal is wider than that in the steady state by time t2. When the input voltage is applied in this state, the input current (primary starting current) becomes excessive as shown in FIG. In the power supply device 300 of the comparative example, the primary starting current is a value exceeding twice the rated value.

[Time t2 to Time t3]
However, since the output voltage of the PFC control unit 110 overshoots when the power is turned on again (time t2), the OFC (overvoltage protection) function operates in the PFC control circuit 114 to temporarily stop the gate drive. Therefore, the input current is temporarily 0 between time t2 and time t3 ((B) in FIG. 5). During this time, the DC / DC converter 118 starts operating, but the output current is not activated. Note that the PFC voltage shown in FIG. 5C becomes maximum with the generation of the primary starting current.

[Time t3]
When the output current of the DC / DC converter starts to rise at time t3, when the output voltage of the PFC control unit 110 drops to the release voltage of the OVP function, the gate drive operates again in the PFC control circuit 114, and the output voltage increases. . However, since the DC / DC converter 118 continues to operate while the PFC control unit 110 is temporarily stopped by the OVP function, the DC / DC converter 118 outputs the output voltage as soon as the OVP function is canceled at time t3. Is a steady load ((A) in FIG. 5). As a result, the output voltage suddenly drops after time t3, whereby the PFC control circuit 114 widens the ON width of the gate drive and restarts after a temporary stop. This time is also shown in FIG. The input current (secondary starting current) becomes excessive. In the power supply device 300 of the comparative example, the secondary starting current is also a value exceeding twice the rated value.

  FIG. 6 is a diagram showing temporal changes in the input voltage and input current on the same time axis as FIG. Among these, (O) in FIG. 6 shows the change of the input voltage, and (B) in FIG. 6 shows the change of the input current. 6B is the same input current as FIG. 5B.

[Input voltage]
In FIG. 6, (O): As described above, the input voltage is stopped at time t1, and is turned on again at time t2 after the instantaneous stop. The input voltage after re-input is the rated value as before the instantaneous stop.

[Input current]
In FIG. 6, (B): On the other hand, the input current is excessive (primary starting current) to twice or more than the rated value at time t2 when the power is turned on again, and further exceeds twice or more than the rated value after time t3. It can be seen that (secondary starting current).

[Gate drive waveform]
FIG. 7 is a diagram showing a gate drive waveform of the PFC control circuit 114 observed in the comparative example.
In the comparative example, the ON width Wo1 of the gate drive signal of the PFC control circuit 114 is expanded from the steady state at the timing when the AC power supply 102 is instantaneously stopped and after being turned on again. This is because, as described above, the output voltage is lower than the steady state during the instantaneous stop, and after the OVP function is released after the reactivation, the DC / DC converter 118 suddenly becomes a steady load and the output voltage drops significantly. is there.

  The inventor of the present invention has created the configuration of the power supply apparatus 100 according to the first embodiment, paying attention to the fact that improving the above-described phenomenon in the comparative example is effective for measures against the primary startup current and the secondary startup current. It has come to be. Hereinafter, the superiority of the first embodiment will be described.

  FIG. 8 is a diagram illustrating various changes when the power supply apparatus 100 according to the first embodiment undergoes an instantaneous power interruption and reactivation. Among these, (A) in FIG. 8 shows the state at that time, and (B) in FIG. 8 shows the input current. Further, “PFC voltage” in (C) in FIG. 8 indicates the charge (voltage) of the electrolytic capacitor C3, and (D) in FIG. 8 indicates the output current of the DC / DC converter 118.

[Before time t1]
Prior to time t1, the state shown in FIG. 8A is “steady”, and the input current shown in FIG. 8B and the PFC voltage shown in FIG. 8C are both rated values (Peak). -Peak). Therefore, the output current shown in (D) in FIG. 8 is constant current controlled to the rated value.

[Time t1 to Time t2]
When the AC power supply 102 is interrupted at time t1, the state shown in FIG. 8A becomes “power failure”, and the input current shown in FIG. 8B stops. The PFC voltage shown in (C) of FIG. 8 decreases due to the discharge of the electrolytic capacitor C3. However, the discharge does not stop at the momentary stop (250 ms or less) from time t1 to time t2.

[Time t2]
However, in the case of the first embodiment, since the input voltage is not applied from the time t1 to the time t2 during the instantaneous stop, the activation voltage is not applied from the activation circuit 120 to the PFC control circuit 114, and the PFC control unit 110 is in a power failure state. The operation has stopped.
Therefore, even when the AC power source 102 is switched to the inverter power source at time t2 and the state shown in FIG. 8A becomes “inverter drive”, the PFC control unit 110 is started again from this point, so that is seen in the comparative example. An excessive input current that exceeds twice the rated value will not occur (measures for primary starting current).

[After time t2]
Also in the first embodiment, since the output voltage slightly overshoots in the PFC control unit 110 when the power is turned on again (time t2), the PFC control circuit 114 operates the OVP (overvoltage protection) function to temporarily stop the gate drive. . Therefore, the input current temporarily becomes 0 after time t2 ((B) in FIG. 8). During this time, the DC / DC converter 118 starts to start, but the output current is 0 because it is not started ((D) in FIG. 8). Note that the PFC voltage shown in FIG. 8C becomes maximum as the power is turned on again.

[Time tg]
Here, in the first embodiment, the DC / DC converter 118 is activated in a light load state from time tg between time t2 and time t3. “Light load state” means that the output current shown in (D) of FIG. 8 is not suddenly subjected to constant current control (PWM control) as a rated value, but is started with a current lower than the rated value as a target value. I mean.

[Time tg to Time t3]
By starting the DC / DC converter 118 in a light load state, the output current shown in FIG. 8D is stabilized at a level lower than the rated value. Further, the PFC voltage shown in FIG. 8C is applied to the DC / DC converter 118 and gradually decreases. Note that the input current shown in FIG. 8B is not generated because the voltage does not drop to the OVP function release voltage during this period.

[Time t3]
When the output voltage of the PFC control unit 110 decreases to the release voltage of the OVP function at time t3, the gate drive operates again in the PFC control circuit 114, and the output voltage increases. At this time, the DC / DC converter 118 continued to operate while the PFC control unit 110 was temporarily stopped by the OVP function. However, the DC / DC converter 118 remains lightly loaded even when the OVP function is released at time t3. (A in FIG. 8). Accordingly, since the output voltage gradually decreases after time t3, the PFC control circuit 114 restarts without particularly increasing the ON width of the gate drive. Accordingly, the input current shown in FIG. 8B is not particularly excessive, and an excessive input current exceeding twice the rated value found in the comparative example is not generated (secondary (Measures for starting current).

[Time t3 to Time t4]
As shown in FIG. 8A, the DC / DC converter 118 operates in a light load state until time t4. During this period, control is performed to gradually increase the output current to the rated value. ((D) in FIG. 8).

[Time t4]
After time t4, the DC / DC converter 118 enters a steady load state ((A) in FIG. 8), and thereafter, the output current is controlled to the rated value ((D) in FIG. 8).

  FIG. 9 is a diagram showing temporal changes in input voltage and input current on the same time axis as FIG. Among these, (O) in FIG. 9 shows the change of the input voltage, and (B) in FIG. 9 shows the change of the input current. Note that (B) in FIG. 9 is the same input current as (B) in FIG.

[Input voltage]
In FIG. 9, (O): As described above, the input voltage is stopped at time t1, and is turned on again at time t2 after the instantaneous stop. The input voltage after re-input is the rated value as before the instantaneous stop.

[Input current]
In FIG. 9, (B): The input current rises at time t2 at the time of recharging, but does not become a value exceeding twice the rated value as seen in the comparative example. Similarly, even after time t3, it will not be excessive to more than twice the rated value.

[Gate drive waveform]
FIG. 10 is a diagram showing a gate drive waveform of the PFC control circuit 114 observed in the first embodiment.
In the first embodiment, the ON width Wo2 of the gate drive signal of the PFC control circuit 114 is suppressed to the same level as the steady state at the timing after the AC power supply 102 is turned on again. This is because the effective range of the output voltage can be suppressed because the DC / DC converter 118 is started in a light load state after the OVP function is released after the reactivation as described above. Note that the gate drive signal is not output during the instantaneous stop because the PFC control unit 110 stops operating.

[Second Embodiment]
FIG. 11 is a circuit diagram schematically showing the configuration of the power supply device 200 of the second embodiment. Similarly, FIG. 12 is a block diagram schematically showing the configuration of the power supply device 200 of the second embodiment. In these FIG.11 and FIG.12, the same code | symbol is attached | subjected to the same structure as 1st Embodiment, and the overlapping description is abbreviate | omitted.

[Starting voltage controller]
The second embodiment is different from the first embodiment in that the configuration of the ON / OFF circuit 124 of the activation circuit is provided.
That is, the ON / OFF circuit 124 of the starting circuit detects the input voltage with the input voltage detection circuit 122, and turns off the ON / OFF circuit 124 itself (switching element Q4) while the input voltage is not applied. Thus, the start circuit 120 is stopped and the PFC control unit 110 (PFC control circuit 114) is not operated. In this case, even if the starting resistor R4 is connected on the cathode side (P3 point) of the diode D1, the starting circuit 120 is stopped while the ON / OFF circuit 128 is OFF, so that the phenomenon as in the comparative example occurs. There is nothing. Therefore, the measures for the primary startup current and the secondary startup current can be effectively functioned as in the first embodiment.

[Output current control section]
FIG. 13 is a flowchart illustrating an exemplary procedure of main control processing executed by the output current control unit 126 of the DC / DC converter 118. This main control process is for starting the DC / DC converter 118 in a light load state as a measure against the secondary starting current, and when the supply of AC power to the power supply devices 100 and 200 is started (powered on). This is started by the control IC of the output current control unit 126. Hereinafter, it demonstrates along the example of a procedure.

  Step S100: The control IC of the output current control unit 126 internally permits (starts) timer interruption. While permitting the timer interrupt, the control IC periodically generates a timer interrupt (for example, every 1 ms), and executes a timer interrupt process (not shown) separate from the main control process.

  Step S102: The control IC of the output current control unit 126 executes the PWM signal output control for initial operation stabilization. Specifically, the first target value of the output current of the DC / DC converter 118 is set to a value lower than the rated value (for example, about 25% of the rated value), and the PWM signal necessary for constant current control with the first target value. Perform output control.

  Step S104: The control IC confirms whether or not the timer interrupt is currently permitted. Here, since the timer interrupt is already permitted in the previous step S100 (Yes), the control IC loops step S102. Thereafter, the control IC continues to loop steps S102 and S104 (Yes) until the timer interrupt is prohibited (terminated). When the timer interrupt is prohibited (terminated) in a separate timer interrupt process (No), the control IC executes step S106 and subsequent steps.

[Control during loop]
Although not specifically shown in the figure, in the timer interruption process, the time required for starting the DC / DC converter 118 in a light load state (for example, about 100 ms to 150 ms) is counted down, and control is performed until this required time elapses. The IC loops through steps S102 and S104.
In the initial operation stabilization PWM output control in step S102, the control IC sets the target output current to a constant current lower than the rated value in the first time zone (time tg to time t3 in FIG. 8). However, in the second time zone (time t3 to time t4 in FIG. 8), control is performed to gradually increase the output current toward the rated value. Thereby, after starting the DC / DC converter 118 in a light load state, it is possible to make a smooth transition gradually toward a steady load state (steady operation).
When the above loop is completed, the control IC executes step S106 and subsequent steps.

  Step S106: The control IC of the output current control unit 126 executes a set value initialization process. In this process, a setting value for PWM control (target value for constant current control) necessary for steady operation of the DC / DC converter 118 is initialized.

[Transition to main loop]
Step S108: The control IC of the output current control unit 126 shifts from here to the main loop and executes the set value confirmation processing. In this process, the control IC constantly checks the ON width value of the gate drive signal set by the PWM control while referring to various input signals (for example, external signals necessary for the dimming operation). For example, when the external signal for dimming changes (for example, changes from dark to bright) with a change in the external environment, the control IC of the output current control unit 126 sets the dimming level of the LED lighting device to “high”. The ON width of the gate drive signal is set.

  Step S110: The control IC outputs a PWM signal with the set ON width, and performs the switching operation of the DC / DC converter 118. As a result, constant current output control according to the rated target value is performed.

  Thereafter, the control IC of the output current control unit 126 repeats the above steps S108 and S110, and while confirming the set value according to the external signal for dimming, the PWM signal is outputted and the output current is steadily changed. Can be controlled.

As described above, according to the power supply devices 100 and 200 of the first and second embodiments, the following utility can be obtained.
(1) When an instantaneous interruption time (250 ms) occurs in an uninterruptible power supply facility with an inverter sleep / standby method (instantaneous interruption time of 250 ms or less), the start-up current with respect to the steady-state current (rated value) value during instantaneous lighting Is less than 2 times "(an electronic ballast standard). In particular, in the LED lighting power source with constant current control having a PFC circuit, the starting current is 2 with respect to the value of the steady current (rated value) with respect to the primary and secondary starting currents generated at the time of starting. It is possible to realize a measure of “double or less”.
(2) In the first embodiment, the generation of the primary starting current can be suppressed with a simple configuration in which the starting circuit 120 is simply connected to the path where the voltage from the electrolytic capacitor C3 is not applied when the input voltage is not applied.
(3) In the second embodiment, since the configuration of the ON / OFF circuit 124 of the startup circuit is used, the generation of the primary startup current can be more actively suppressed.
(4) Since the main control process of FIG. 13 is a general-purpose logic as a process executed by the control IC of the output current control unit 126, it is possible to easily implement a countermeasure for the secondary startup current only by adjusting the program in step S102. It is.

  The present invention can be implemented with various modifications without being limited to the above-described embodiments. For example, the detailed hardware configuration of the power supply apparatuses 100 and 200 is not limited to the illustrated example, and can be changed as appropriate.

  In each embodiment, 250 ms is exemplified as the instantaneous stop time. However, the present invention may be applied to the case where the instantaneous stop and re-input occur under different conditions.

  In each embodiment, the current value controlled by the control IC of the output current control unit 126 in the light load state is set to about 25% of the rated value. However, the setting of the target value is not particularly limited, and the light load is appropriately set. The level may be appropriately changed as long as it can be activated in the state.

100, 200 Power supply device 102 AC power supply 104 Rectifier 108 Ripple filter 110 PFC controller 116 Output voltage detector 118 DC / DC converter 120 Start-up circuit 121 Load 124 Input voltage detector 126 Output current controller 128 ON / OFF circuit

Claims (4)

A rectifying unit for generating an input voltage obtained by rectifying an AC voltage;
A PFC control unit for generating an output voltage by performing power factor correction control on the input voltage;
A DC / DC converter that converts the output voltage of the PFC controller and outputs a DC voltage;
A starting circuit for applying a starting voltage to the PFC control unit using an internal voltage generated between the rectifying unit and the DC / DC converter;
When the input voltage is applied, the start-up circuit can apply the start-up voltage to the PFC control unit, while when the input voltage is not applied, the start-up circuit can apply the start-up voltage to the PFC control unit. The power supply device provided with the starting voltage control part to suppress. The power supply device according to claim 1,
Output current for controlling the output current from the DC / DC converter to the load to be lower than the steady value at the start of the generation of the output voltage by the PFC control unit and gradually increasing the output current toward the steady value as time elapses A power supply apparatus further comprising a control unit. The power supply device according to claim 1 or 2,
An electrolytic capacitor for charging the output voltage before the DC / DC converter;
The starting voltage controller is
The power supply device is connected to a path through which no voltage from the electrolytic capacitor is applied when the input voltage is not applied. The power supply device according to claim 1 or 2,
The starting voltage controller is
An input voltage detector for detecting the input voltage;
A power supply apparatus comprising: an ON / OFF circuit that stops the starter circuit when application of the input voltage is not detected by the input voltage detector.

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