JP5281471B2 - Power supply - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power supply apparatus for reducing the probability of occurrence of a fault when the apparatus is used by exceeding assumed life of the apparatus. <P>SOLUTION: The power supply apparatus is provided with a DC power supply circuit 1 converting pulsating voltage which is rectified AC voltage from an AC power supply AC into DC voltage of a prescribed size, a load circuit 2 receiving output voltage of the DC power supply circuit 1 and supplying lighting power to a discharge lamp La, an output voltage detecting part 11 detecting output voltage of the DC power supply circuit 1, a DC power supply control circuit 5 controlling output voltage of the DC power supply circuit 1 to a prescribed voltage, an abnormality judging part 54 judging whether or not output voltage of the DC power supply circuit 1 exceeds a prescribed overvoltage exceeding a prescribed voltage and stopping an operation of the DC power supply control circuit 1 for a fixed time when voltage exceeds a prescribed overvoltage, and a clocking part 44 accumulating and clocking time equivalent to operation time of the DC power supply control circuit 1. When time clocked by the clocking part 44 exceeds a prescribed time, an operation of the abnormality judging part 54 is stopped for the fixed time after the DC power supply control circuit 5 starts the operation. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a power supply apparatus that supplies operating power to a load such as a discharge lamp.

  Conventionally, in a power supply device that supplies operating power to a load such as a discharge lamp, the lifetime of electronic components such as a rectifier, a switching element for generating a high-frequency voltage, and a smoothing capacitor is determined. There are known devices that provide a means for informing the user of the fact or performing a protection operation by a protection circuit, and are disclosed in Patent Documents 1 and 2, for example. As means for determining the lifetime, there is, for example, a method for determining the lifetime of the power supply device based on a preset lifetime. In this case, it can be realized with a relatively simple configuration in which the lifetime is stored in the memory in advance and the usage time is counted by the microcomputer. Also, a means for detecting some parameter of the electronic component constituting the apparatus and determining the life of the power supply device from the change of the parameter due to the aging of the electronic component is conceivable.

  On the other hand, as means for informing the user when the power supply device has reached the end of its life, for example, means for increasing or decreasing the amount of light emitted from the light source from the normal time or repeating blinking of the light source can be considered. These means have a simple configuration as compared with the case where a separate notification means is provided, and can be realized at low cost. As described above, when it is determined that the power supply device has reached the end of its life, the user is notified of the fact, thereby prompting the user to stop using the power supply device or replace electronic components constituting the power supply device. be able to.

JP 2001-185374 A JP 2006-236635 A

  By the way, the lifetime of the power supply device as described above is determined according to a period in which the manufacturer guarantees reliability and safety, and the actual lifetime of the power supply device is almost always longer than the lifetime assumed by the manufacturer. is there. In particular, recently, since the stress applied to the electronic components has been reduced by providing a protection circuit in the power supply device, the power supply device can be used for a period far exceeding the life expected by the manufacturer. For this reason, it is unwilling to be prompted by the user to stop the power supply or replace electronic parts even though it is still usable. May continue to use.

  However, when a power supply device is used beyond the lifetime assumed by the manufacturer, there is a high possibility that the power supply device will fail in proportion to the period of use. If a problem occurs in the power supply device, there is a risk that it will be disadvantageous for both the manufacturer and the user.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a power supply device that can reduce the occurrence probability of a malfunction when the device is used beyond the expected life of the device. .

  In order to achieve the above object, a first aspect of the present invention provides a DC power supply circuit for converting a pulsating voltage obtained by rectifying a DC voltage from a DC power supply or an AC voltage from an AC power supply into a DC voltage of a predetermined magnitude; A load circuit that receives the output voltage of the DC power supply circuit and supplies operating power to the load, an output voltage detector that detects the output voltage of the DC power supply circuit, and an output of the DC power supply circuit according to the detection result of the output voltage detector DC power supply control circuit for controlling the voltage to a predetermined voltage, and whether the output voltage of the DC power supply circuit exceeds a predetermined overvoltage higher than the predetermined voltage in response to the detection result of the output voltage detection unit, and a predetermined If the overvoltage exceeds the specified voltage, the abnormality determination unit stops the operation of the DC power supply control circuit for a certain period of time, and the timekeeping unit measures the time corresponding to the operation time of the DC power supply control circuit. Characterized in that stops the operation of the abnormality determination unit until greater than the constant time when at least a DC power supply control circuit has passed a predetermined time from the start of the operation.

  According to the present invention, since the protection operation is temporarily stopped when the expected life of the device is reached, the electronic components constituting the device can be intentionally stressed. And can lead to failure of electronic components. Therefore, it is possible to shorten the time until the electronic component fails after reaching the expected life of the device, and even if the user uses the device beyond the expected life of the device, the usage period is intentional. By shortening to a short time, it is possible to reduce the probability that the apparatus will malfunction.

It is a circuit diagram which shows Embodiment 1 of the power supply device which concerns on this invention. (A)-(g) is a time chart for demonstrating a control circuit same as the above. It is a circuit diagram which shows an inverter control circuit same as the above. (A)-(f) is a time chart for demonstrating the sequence control same as the above. It is a circuit diagram which shows a stop execution part same as the above. (A)-(g) is a time chart for demonstrating a stop execution part same as the above. It is a flowchart for demonstrating the basic operation | movement of an operation setting circuit same as the above. It is a circuit diagram which shows a direct-current power supply control circuit and abnormality determination part same as the above. (A)-(d) is a time chart for demonstrating the case where the abnormality determination part same as the above is not operate | moving. (A)-(d) is a time chart for demonstrating the case where the abnormality determination part same as the above is operate | moving. It is a circuit diagram which shows Embodiment 2 of the power supply device which concerns on this invention.

(Embodiment 1)
Hereinafter, Embodiment 1 of the power supply device according to the present invention will be described with reference to the drawings. In this embodiment, the load circuit 2 converts the DC voltage from the DC power supply circuit 1 into a high-frequency voltage, and a high-frequency voltage from the inverter unit 20 is applied to the discharge circuit due to the resonance action as will be described later. The resonance circuit 21 is configured to turn on La, and is configured to supply lighting power to the discharge lamp La. However, the load circuit 2 is not limited to the configuration, and a load other than the discharge lamp La is used. It may be configured to supply operating power.

  In this embodiment, as shown in FIG. 1, a rectifier circuit DB composed of a diode bridge that rectifies an AC voltage from an AC power supply AC and outputs a pulsating voltage, and boosts and smoothes the pulsating voltage from the rectifier circuit DB. A DC power supply circuit 1 that outputs a DC voltage, a load circuit 2 that converts the DC voltage from the DC power supply circuit 1 into a high-frequency voltage and applies the high-frequency voltage to the discharge lamp La to light the discharge lamp La; A control circuit 3 having a DC power supply control circuit 5 for controlling the power supply circuit 1 and an inverter control circuit 6 for controlling an inverter unit 20 to be described later of the load circuit 2, and an operation setting circuit 4 for setting an operation in the control circuit 3. Consists of

  The DC power supply circuit 1 is a step-up chopper circuit including an inductor L1, a switching element Q1, a diode D1, and a smoothing capacitor C1, and the switching element Q1 is turned on / off according to a drive signal from a DC power supply control circuit 5 described later. Is switched to boost the pulsating voltage from the rectifier circuit DB, and a DC voltage obtained by smoothing the boosted pulsating voltage is supplied to the load circuit 2. An input voltage detector 10 for detecting an input voltage of the DC power supply circuit 1 is provided on the input side of the DC power supply circuit 1, and an output voltage of the DC power supply circuit 1 is detected on the output side. An output voltage detector 11 is provided. Further, the switching element Q1 is formed of a MOSFET, and its gate terminal is connected to a first drive unit 50 described later via a resistor R1. A resistor R2 is connected to the source terminal of the switching element Q1, and a voltage drop in the resistor R2 is input to a non-inverting input terminal of a second operational amplifier OP2, which will be described later. Note that the input voltage detection unit 10 and the output voltage detection unit 11 are both composed of resistors and capacitors (see FIG. 5 for the input voltage detection unit 10), and are well known, so detailed description thereof is omitted here.

  The load circuit 2 has a pair of switching elements Q2 and Q3 connected in series, and alternately switches on / off these switching elements Q2 and Q3 according to a drive signal from an inverter control circuit 6 described later. The inverter unit 20 that converts a DC voltage from the DC power supply circuit 1 into a high-frequency voltage, capacitors C2 and C3, and an inductor L2, the high-frequency voltage from the inverter unit 20 is applied to the discharge lamp La by resonance action. A resonating unit 21 to be lit, capacitors C4, C5, C6, and a transformer T1, a preheating unit 22 that preheats the discharge lamp La by applying a high frequency voltage from the inverter unit 20, and a high frequency voltage from the inverter unit 20 The control power generation circuit 23 is applied to generate a second control power supply Vcc2 to be described later. The switching elements Q2 and Q3 are both formed of MOSFETs, and resistors R3 and R4 are inserted between the gate terminals of the switching elements Q2 and Q3 and a second driving unit 60 described later.

  The control circuit 3 receives the output voltage of the DC power supply circuit 1 and activates the second control power supply Vcc2, the power supply voltage of the second control power supply Vcc2, and the power supply voltage of the second reference voltage source Vref2. Control power source comparison unit 31, a first control power source generation unit 32 that generates a first control power source Vcc1 according to the comparison result of the control power source comparison unit 31, and an output signal from a stop execution unit 34 described later The operation of the first drive unit 50 and the second drive unit 60 according to the determination result of the third control power generation unit 33 that generates the third control power supply Vcc3 according to the determination result of the stop determination unit 42 described later. It comprises a stop execution unit 34 to be controlled, and a time determination unit 35 that controls the operation of an abnormality determination unit 54 to be described later in accordance with an output signal from a notification unit 46 to be described later.

  The operation setting circuit 4 is composed of a microcomputer, a sequence control unit 40 that performs sequence control of a frequency setting unit 41 and a stop determination unit 42, which will be described later, and a frequency for setting the drive frequency of the switching elements Q2 and Q3 of the inverter unit 20. A frequency setting unit 41 that outputs a setting signal, a stop determination unit 42 that outputs a stop signal for stopping the operation of the first drive unit 50 and the second drive unit 60 according to the sequence control by the sequence control unit 40, A period setting unit 43 for setting the clock cycle of the operation setting circuit 4; a time measuring unit 44 for measuring the operation time of the DC power supply control circuit 5; a storage unit 45 for storing the time measured by the time measuring unit 44; When the accumulated time counted at 44 exceeds a predetermined time, a notification unit 46 outputs a life notification signal to the time determination unit 35.

  The DC power supply control circuit 5 includes a first drive unit 50 that outputs a drive signal for switching on / off of the switching element Q1 of the DC power supply circuit 1, and an inductor via a secondary winding of the inductor L1 of the DC power supply circuit 1. The zero current detector 51 for detecting the zero point of the current flowing through L1, the RS flip-flop 52 for controlling the operation of the first driver 50, the detection voltage of the output voltage detector 11, and the first reference voltage source Vref1 The first operational amplifier OP1 that compares the power supply voltage, the multiplier 53 that multiplies the detection voltage of the input voltage detector 10 and the output voltage of the first operational amplifier OP1, and the voltage drop in the resistor R2 of the DC power supply circuit 1 And the second operational amplifier OP2 that compares the output voltage of the multiplier 53, and an abnormality determination that receives the detection voltage of the output voltage detection unit 11 and determines an abnormality in the output voltage of the DC power supply circuit 1. Consisting of part 54.

  The inverter control circuit 6 includes a second drive unit 60 that outputs a drive signal for alternately switching on / off the switching elements Q2 and Q3 of the inverter unit 20, and a frequency output from the frequency setting unit 41 of the operation setting circuit 4. A frequency variable unit 61 that varies the frequency of the drive signal in accordance with the setting signal.

  Hereinafter, the operation of this embodiment will be described. First, the operation of the control circuit 3 will be described with reference to the drawings. When the power supply of this embodiment is turned on, the output voltage of the DC power supply circuit 1 is input to the load circuit 2 and the starter 30 of the control circuit 3 in the subsequent stage. Immediately after the power is turned on, the output voltage of the DC power supply circuit 1 is a smoothed voltage obtained by smoothing the AC voltage of the AC power supply AC with the smoothing capacitor C1. ) Is turned on, and the second control power supply Vcc2 is started (see FIGS. 2A and 2B). The starting unit 30 may have any configuration as long as it can generate the second control power supply Vcc2 of the control circuit 3.

  The power supply voltage of the second control power supply Vcc2 is compared with the power supply voltage of the second reference voltage source Vref2 in the control power supply comparison unit 31. When the power supply voltage of the second control power supply Vcc2 exceeds the power supply voltage of the second reference voltage source Vref2, the first control power supply Vcc1 is generated in the first control power supply generation unit 32, and the first control power supply is generated. The power supply voltage of Vcc1 is supplied to the operation setting circuit 4 (see FIG. 2C). When a predetermined time T1 elapses after the power supply voltage of the first control power supply Vcc1 is supplied, a high level signal is output from the stop execution unit 34, and the third control power generation unit 33 receives the high level signal and the third control power generation unit 33 receives the high level signal. 3 is generated (see FIGS. 2D and 2F). The operation of the first drive unit 50 of the DC power supply control circuit 5 is started by supplying the power supply voltage of the third control power supply Vcc3 (see FIG. 2E). The power supply voltage of the third control power supply Vcc3 is also supplied to the frequency variable unit 61 of the inverter control circuit 6, and the frequency variable unit 61 also starts operation at the same timing as the first drive unit 50. Details of the operation setting circuit 4 will be described later.

  Next, the frequency variable unit 61 will be described with reference to the drawings. As shown in FIG. 3, the frequency variable unit 61 includes a constant voltage circuit composed of a third operational amplifier OP3, a load impedance circuit composed of resistors R5 and R6 connected to the output terminal of the third operational amplifier OP3, Each having a fourth operational amplifier OP4 to which the power supply voltage of the reference voltage source Vref3 is input to the non-inverting input terminal, and adjusting the current flowing through the capacitor C8 according to the current flowing through the load impedance circuit, A first multiplexer circuit MP1 having a pair of transfer gate elements connected to the fourth reference voltage source Vref4 and the fifth reference voltage source Vref5, and between the output voltage of the first multiplexer circuit MP1 and both ends of the capacitor C8 An oscillation circuit composed of a fifth operational amplifier OP5 for comparing the voltage and the switching of the inverter unit 20 Elements Q2, Q3 are composed of a dead time generation unit 61a for generating a dead time for preventing the turning on simultaneously.

  A frequency setting signal output from the frequency setting unit 41 of the operation setting circuit 4 is input to the non-inverting input terminal of the third operational amplifier OP3 via a filter circuit including resistors R7, R8, R9 and a capacitor C7. The The frequency setting signal is a rectangular wave signal having a predetermined duty ratio as shown in FIG. 4D, for example, and is converted into a DC signal corresponding to the duty ratio in the filter circuit. Here, since the output terminal of the third operational amplifier OP3 is connected to the output terminal of the fourth operational amplifier OP4 via the resistor R5, the output of the third operational amplifier OP3 is changed by changing the duty ratio of the frequency setting signal. The magnitude of the current flowing from the terminal to the output terminal of the fourth operational amplifier OP4 changes. Thus, by varying the duty ratio of the frequency setting signal, the current flowing through the capacitor C8 can be varied, and the drive frequency of the drive signal can be varied.

  The drive signals are input to the high-side drive unit 60a and the low-side drive unit 60b of the second drive unit 60 via the dead time generation unit 61a, and the switching elements Q2 and Q3 are turned on / off by the drive units 60a and 60b. Off is controlled.

  Next, the DC power supply control circuit 5 will be described with reference to the drawings. The DC power supply control circuit 5 repeatedly stores energy in the inductor L1 and discharges energy from the inductor L1 by switching on / off the switching element Q1, and switches the switching element Q1 on. Is performed at the timing of energy release from the inductor L1. For this reason, the DC power supply control circuit 5 is provided with a zero current detection unit 51. The zero current detection unit 51 detects the timing at which the secondary winding voltage of the inductor L1 falls near 0V, thereby causing the inductor L1. Is determined, that is, the timing at which energy is released from the inductor L1. When the zero current detection unit 51 determines that energy is released from the inductor L1, a high level signal is input to the set terminal of the RS flip-flop 52, and the switching element Q1 is turned on via the first drive unit 50.

  When the switching element Q1 is on, the current flowing through the switching element Q1 is detected by the resistor R2, and the voltage drop at the resistor R2 is compared with the output voltage of the multiplier 53 by the second operational amplifier OP2. When the voltage drop in the resistor R2 exceeds the output voltage of the multiplier 53, that is, when the current flowing through the switching element Q1 exceeds a predetermined value, a high level signal is input to the reset terminal of the RS flip-flop 52, The switching element Q1 is switched off via the drive unit 50. The predetermined value is determined by performing feedback control by comparing the detection voltage of the output voltage detection 11 of the DC power supply circuit 1 with the power supply voltage of the reference voltage source Vref1 in the first operational amplifier OP1.

  Hereinafter, the sequence control of the present embodiment will be described with reference to the time chart shown in FIG. A pre-heating period for preheating the filament of the discharge lamp La, a starting period for applying a high voltage to the discharge lamp La using a resonance action to start the discharge lamp La, and lighting for lighting the discharge lamp La with a desired light output Conventionally, the sequence control of each period is generally performed. In the present embodiment, the sequence control is performed using the operation setting circuit 4.

  As shown in FIG. 4A, when the first control power supply Vcc1 rises and the power supply voltage is supplied to the operation setting circuit 4, the input signal to the stop execution unit 34 is the moment when the first control power supply Vcc1 rises. After reaching the high level, the low level is reached (see FIG. 4B). Then, the operations of the frequency variable unit 61, the first drive unit 50, and the second drive unit 60 are stopped for a predetermined period T1 until the output signal of the stop execution unit 34 becomes high level.

  Here, when the power supply voltage is supplied from the first control power supply Vcc1, the microcomputer configuring the operation setting circuit 4 operates a preset initial activation program to assign functions to the microcomputer terminals. The terminal impedance may be infinite. Therefore, in this embodiment, the resistor R10 is connected between the first control power supply Vcc1 and the output terminal of the stop determination unit 42 to prevent the output of the microcomputer terminal from becoming unstable.

  When the predetermined period T1 has elapsed, as shown in FIG. 4C, the stop signal from the stop execution unit 34 becomes a high level, and the operations of the frequency variable unit 61, the first drive unit 50, and the second drive unit 60 are performed. Starts, and the inverter unit 20 operates at the drive frequency set by the frequency setting unit 41. Here, as shown in FIG. 4D, the frequency setting signal output from the frequency setting unit 41 is a preceding preheating period from time t1 to time t2 when the operation of the inverter unit 20 is started, and from time t2 to time t3. The duty ratio is varied in each of the starting period until and the lighting period after time t3. For this reason, the output signal of the third operational amplifier OP3 changes as shown in FIG. 4E in accordance with the change in the duty ratio of the frequency setting signal. Therefore, the drive frequency is sequentially varied as a frequency f1 during the preceding preheating period, a frequency f2 during the starting period, and a frequency f3 during the lighting period (see FIG. 4 (f)). Thus, the discharge lamp La lights up after the preceding preheating period and the starting period.

  Here, the time constant of the filter circuit composed of the resistors R7, R8, R9 and the capacitor C7 provided before the input of the third operational amplifier OP3 is set so that the output voltage of the filter circuit is stabilized during the predetermined period T1. By setting, the output voltage of the third operational amplifier OP3 at the start of the preceding preheating period is stabilized (see FIG. 4E), so that the drive frequency can be stabilized.

  Note that the preceding preheating period and the starting period may be determined by the operation setting circuit 4 and may generally be measured by a built-in oscillator or timer circuit incorporated in the microcomputer. In the present embodiment, the program processing speed of the microcomputer is determined based on a clock cycle set by a cycle setting unit 43 described later.

  Further, the frequency setting signal output from the frequency setting unit 41 has a duty ratio of 0% in the preceding preheating period, and the duty ratio is increased for the first time in the starting period after the operation of the inverter unit 20 is stabilized. Current consumption in the control circuit 3 and the operation setting circuit 4 immediately after the start of the operation of the inverter unit 20 can be reduced, and supply of power supply voltage from each control power supply can be stabilized. Further, when the operation of the inverter unit 20 is stopped, the stop signal from the stop determination unit 42 is set to the high level (that is, the input signal to the stop execution unit 34 is set to the high level), so that no current flows through the resistor R10. Thus, current consumption in the control circuit 3 when the operation of the inverter unit 20 is stopped can be reduced. In addition, by processing the input / output signals of the microcomputer constituting the operation setting circuit 4 with two levels of high level and low level without using the A / D conversion circuit and the D / A conversion circuit, the microcomputer Current consumption can be significantly reduced.

  Next, the stop execution unit 34 will be described with reference to the drawings. As shown in FIG. 5, the stop execution unit 34 includes a stop signal input unit 34a to which the detection voltage of the input voltage detection unit 10 and the stop signal voltage from the stop determination unit 42 are input, and an output from the stop signal input unit 34a. Upon receiving the signal, the frequency variable unit 61, the first drive unit 50, and the second drive unit 60 include a stop time measuring unit 34b that measures the time for stopping the operation.

  The stop signal input unit 34a includes a sixth operational amplifier OP6 in which the power supply voltage of the sixth reference voltage source Vref6 is input to the non-inverting input terminal and the detection voltage of the input voltage detection unit 10 is input to the inverting input terminal. The seventh operational amplifier OP7 in which the stop signal voltage from the stop determination unit 42 is input to the non-inverting input terminal and the power supply voltage of the sixth reference voltage source Vref6 is input to the inverting input terminal, and the operational amplifiers OP6 and OP7 It is comprised from OR element OR1 into which an output signal is input.

  The stop time measuring unit 34b is formed of a MOSFET, and includes a switching element Q4 whose gate terminal receives an output signal from the stop signal input unit 34a, a capacitor C9 connected to the drain terminal of the switching element Q4, and a current flowing through the capacitor C9. From the constant current source Iref1 and the eighth operational amplifier OP8 in which the voltage across the capacitor C9 is input to the non-inverting input terminal and the power supply voltage of the seventh reference voltage source Vref7 is input to the inverting input terminal. Composed. The switching element Q4 is switched on / off according to the output signal from the stop signal input unit 34a. When the switching element Q4 is off, the switching element Q4 is determined by the current flowing from the constant current source Iref1 and the capacitance of the capacitor C9. The capacitor C9 is charged during the charging time.

  Here, the sixth operational amplifier OP6 outputs a high-level signal when the detection voltage of the input voltage detection unit 10 exceeds a predetermined voltage (power supply voltage of the sixth reference voltage source Vref6). On the other hand, the seventh operational amplifier OP7 outputs a low level signal when the stop signal from the stop determination unit 42 is low level, and outputs a high level signal when the stop signal is high level. Therefore, only when the detection voltage of the input voltage detection unit 10 is equal to or lower than the predetermined voltage and the stop signal from the stop determination unit 42 is at a low level, the switching element Q4 is switched off and the capacitor C9 is charged. Then, when the charging voltage of the capacitor C9 exceeds a predetermined voltage (power supply voltage of the seventh reference voltage source Vref7), a high level signal is output from the eighth operational amplifier OP8, and the third control power generation unit as described above. In 33, the third control power supply Vcc3 is generated, and the operations of the frequency variable unit 61, the first drive unit 50, and the second drive unit 60 are started (see FIGS. 6A to 6F). That is, the charging time of the capacitor C9 is the predetermined period T1, and the operation of the inverter unit 20 is stopped during the period.

  The basic operation of the operation setting circuit 4 will be described below with reference to the flowchart shown in FIG. First, when a power supply voltage is supplied from the first control power supply Vcc1 (the first control power supply Vcc1 is turned on) (S1), an initial startup program operates to perform initial setting (S2), and a cycle setting unit 43 starts the operation (S3). The clock signal generated by the period setting unit 43 is used as a basic clock of the microcomputer constituting the operation setting circuit 4, and in the present embodiment, two clock signals having periods TA and TB (TA> TB) are switched as appropriate. Used. Since the current consumption in the microcomputer increases as the period of the clock signal becomes shorter, the clock signal having the period TA is used first here.

  Next, the information on the duty ratio of the frequency setting signal stored in advance is read (S4), and the frequency setting signal to be output is set (S5). Thereafter, time measurement is started (S6), and the operation period is determined based on the time measured (S7). That is, when the time t1 is reached, it is determined that the preceding preheating period is reached and the frequency setting signal is set so that the driving frequency becomes the frequency f1 (S9), and when the time t2 is reached, the starting period is determined and the driving frequency becomes the frequency f2. The frequency setting signal is set so as to be (S10), and when the time t3 is reached, the lighting period is determined and the frequency setting signal is set so that the driving frequency becomes the frequency f3 (S12). Note that the operation of the inverter unit 20 is stopped during a predetermined period T1 from when the operation setting circuit 4 is activated to when the time t1 is reached (S8).

  By the way, in this embodiment, although not shown, a conventionally known abnormality detection circuit for detecting abnormality such as whether or not the discharge lamp La is normally mounted and whether or not the life of the discharge lamp La is exhausted is separately provided. The operation of the control circuit 3 is stopped when an abnormality is detected in the abnormality detection circuit during the above operation. Thus, when detecting the life of the discharge lamp La, it is necessary to immediately operate the life detection particularly during the lighting period of the discharge lamp La.

  Therefore, when shifting to the lighting period, the cycle setting unit 43 switches the cycle of the clock signal to the cycle TB (S11). By switching the clock signal cycle to the cycle TB shorter than the cycle TA in this way, the processing speed of the microcomputer is increased and the life detection is immediately operated. Note that the timing for switching the cycle is not limited to the transition to the lighting period as described above, but from the start of the preceding preheating period to the transition to the lighting period, that is, the inverter unit 20 operates. As long as the power supply voltage of the second control power supply Vcc2 is stably supplied to the control circuit 3 from the control power supply generation circuit 23 (for example, FIG. )reference).

  Further, when detecting the abnormality and stopping the operation of the control circuit 3 as described above, if the cycle of the clock signal is the cycle TB, the cycle setting unit 43 switches the cycle of the clock signal to the cycle TA. Thus, the current consumption in the operation setting circuit 4 is reduced. Thus, the stress applied to the starting unit 30 can be reduced, and the supply of the power source voltage from each control power source can be stabilized when the operation of the inverter unit 20 is resumed.

  By the way, in this embodiment, when the power supply voltage from the third control power supply Vcc3 is supplied to the operation setting circuit 4, it is determined that the DC power supply control circuit 5 is operating, and the operation setting circuit 4 counts time. The unit 44 measures the operating time of the DC power supply control circuit 5. This operation time is read from the storage unit 45 every time the DC power supply control circuit 5 starts or stops operation, or is accumulated and timed by being overwritten in the storage unit 45. When this accumulated time exceeds a predetermined time (for example, 30,000 hours generally defined as the life of a lighting fixture), it is determined that the life of the present embodiment is approaching and the notification unit 46 determines that the control circuit 3 A life notification signal is output to the time determination unit 35.

  Hereinafter, operations of the time determination unit 35 and the abnormality determination unit 54 of the DC power supply control circuit 5 when the life notification signal is output will be described with reference to the drawings. As shown in FIG. 8, the abnormality determination unit 54 receives the detection voltage of the output voltage detection unit 11 at the non-inverting input terminal and the power supply voltage of the eighth reference voltage source Vref8 at the inverting input terminal. The ninth operational amplifier OP9 includes an AND element AND1 to which the output signal of the ninth operational amplifier OP9 and the output signal of the time determination unit 35 are input. The time determination unit 35 includes a tenth operational amplifier OP10 in which the power supply voltage of the ninth reference voltage source Vref9 is input to the non-inverting input terminal and the life notification signal from the notification unit 46 is input to the inverting input terminal. Is done.

  Generally, when the operation of the DC power supply control circuit 5 is started, the output voltage of the DC power supply circuit 1 once rises to a voltage higher than a predetermined voltage due to a response delay of the first operational amplifier OP1, and then gradually decreases to the predetermined voltage. And stabilize. The abnormality determination unit 54 detects a predetermined overvoltage that is higher than the predetermined voltage, determines an abnormality, and stops the operation of the DC power supply circuit 1. Specifically, the detection voltage of the output voltage detection unit 11 and the power supply voltage of the eighth reference voltage source Vref8 are compared by the ninth operational amplifier OP9, and the detection voltage exceeds the power supply voltage of the eighth reference voltage source Vref8. That is, when the output voltage of the DC power supply circuit 1 becomes a predetermined overvoltage higher than the predetermined voltage, a high level signal is output from the ninth operational amplifier OP9, and the high level signal is output to the reset terminal of the RS flip-flop 52 via the AND element AND1. When the level signal is input, the switching element Q1 is turned off and the boosting operation is stopped. For this reason, as shown in FIGS. 10A and 10B, a portion of the output voltage of the DC power supply circuit 1 that is higher than the predetermined overvoltage is cut, and the DC power supply circuit 1 such as the switching element Q1 is cut. Protects the electronic components that make up from stress caused by overvoltage.

  The power supply voltage of the eighth reference voltage source Vref8 only needs to be larger than the power supply voltage of the first reference voltage source Vref1 that determines the target value of the output voltage of the DC power supply circuit 1. For example, the target value of the output voltage of the DC power supply circuit 1 is 400 V, the power supply voltage of the first reference voltage source Vref1 is 2.5 V, and the output voltage of the DC power supply circuit 1 rises to 110% of the target value. Is determined, the power supply voltage of the eighth reference voltage source Vref8 is 2.75V.

  Here, the abnormality determination operation is performed when the output signal from the time determination unit 35 of the AND element AND1 is high level, and when the output signal from the time determination unit 35 is low level, the AND element Since the output signal of AND1 is at a low level, the abnormality determination operation is not performed. The output signal of the time determination unit 35 becomes low level when the life notification signal from the notification unit 46 exceeds the power supply voltage of the ninth reference voltage source Vref9 in the tenth operational amplifier OP10. This is a case where it is determined that the life of the form is approaching and a high-level life notification signal is output from the notification unit 46.

  That is, in the normal time when the life of the present embodiment is not approaching, the abnormality determination unit 54 performs the abnormality determination operation at the start of the operation of the DC power supply control circuit 5 as described above, and the electronic components constituting the DC power supply circuit 1 are Although protection from stress due to overvoltage is made, if it is determined that the life of the present embodiment is approaching, the DC power supply circuit 1 is deliberately set not to perform an abnormality determination operation when the operation of the DC power supply control circuit 5 is started. Stress due to overvoltage is applied to the constituent electronic components, and the electronic components are safely brought to failure (see FIGS. 9A to 9C). Even when it is determined that the life of the present embodiment is approaching, the life notification signal from the notification unit becomes a low level after a predetermined time has elapsed, and the abnormality determination operation is performed in the same manner as in normal times, for example, Failure due to the occurrence of overvoltage after the discharge lamp La is turned on is prevented (see FIG. 9D).

  As described above, when the expected life of the device is reached, the abnormality determination operation (protection operation) is temporarily stopped, so that the electronic components constituting the device can be intentionally stressed. It is possible to increase the chance of failure and lead to the failure of the electronic component. Therefore, it is possible to shorten the time until the electronic component fails after reaching the expected life of the device, and even if the user uses the device beyond the expected life of the device, the usage period is intentional. By shortening to a short time, it is possible to reduce the probability that the apparatus will malfunction.

  By the way, as described in the background art, as means for notifying the user when the power supply device has reached the end of its life, for example, means for increasing or decreasing the amount of light emitted from the light source, or repeating blinking of the light source. Can be considered. Here, for example, when a plurality of power supply devices are used in a place where a relatively large number of people gather, such as an office building or a large store, when all the power supply devices are employed, all the power supply devices However, there is a risk of notifying the failure all at once. In such a case, the amount of light from all the light sources may increase or decrease all at once, or all the light sources may blink repeatedly, which may cause great discomfort and anxiety to people who are present.

  Therefore, if a plurality of the present embodiments are used, it is possible to cause each device to fail at different times determined by the influence of variations in stress resistance of electronic components and variations in characteristics of peripheral components, the usage environment of the devices, and the like. Therefore, it is possible to prevent all the power supply devices from failing at the same time as described above, so that it is possible to avoid the situation where all the power supply devices fail at the same time and all the lights simultaneously increase or decrease or blink. Can do.

(Embodiment 2)
Hereinafter, Embodiment 2 of the power supply device according to the present invention will be described with reference to the drawings. However, since the basic configuration of the present embodiment is common to that of the first embodiment, common portions are denoted by the same reference numerals and description thereof is omitted. As shown in FIG. 11, the present embodiment is characterized by an abnormality determination unit 54, which is connected to a tenth reference voltage source Vref10 and an eleventh reference voltage source Vref11 instead of the AND element AND1. A second multiplexer circuit MP2 having a gate element is provided, and its input terminal is connected to the output terminal of the tenth operational amplifier OP10 of the time determination unit 35, and the output terminal and the inverting input terminal of the ninth operational amplifier OP9 are connected. Connected.

  Therefore, when the output signal of the time determination unit 35 is high level (when the lifetime of the device is not approaching), the power supply voltage of the tenth reference voltage source Vref10 is input to the inverting input terminal of the ninth operational amplifier OP9. When the output signal of the time determination unit 35 is at a low level (when the lifetime of the device is approaching), the power supply voltage of the eleventh reference voltage source Vref11 is input to the inverting input terminal of the ninth operational amplifier OP9. It has become. That is, in this embodiment, the abnormality determination operation is performed both in the normal case where the life of the apparatus is not approaching and in the case where the life of the apparatus is approaching. When the life of the device is approaching, the power supply voltage of the eleventh reference voltage source Vref11 is made larger than the power supply voltage of the tenth reference voltage source Vref10 in order to increase the stress due to overvoltage on the electronic components. ing.

  Here, in the first embodiment, when it is determined that the life of the apparatus is approaching, the abnormality determination operation is not performed. Therefore, when the operation of the DC power supply control circuit 5 is started, no control is performed on the overvoltage exceeding the target voltage in the output voltage of the DC power supply circuit 1. In this case, since the maximum value of the overvoltage differs depending on the effective voltage value of the AC power supply AC, there is a possibility that a difference occurs in stress due to the overvoltage on the electronic component.

  On the other hand, in this embodiment, since the abnormality determination operation is performed even when it is determined that the life of the apparatus is approaching as described above, the level of the overvoltage can be made constant, and the electronic component is caused by the overvoltage. Stress can be kept constant.

DESCRIPTION OF SYMBOLS 1 DC power supply circuit 11 Output voltage detection part 2 Load circuit 44 Timekeeping part 5 DC power supply control circuit 54 Abnormality judgment part AC AC power supply La discharge lamp

Claims (1)

  A DC power supply circuit that converts the DC voltage from the DC power supply or the pulsating voltage obtained by rectifying the AC voltage from the AC power supply into a DC voltage of a predetermined magnitude, and receives the output voltage of the DC power supply circuit to supply operating power to the load A load circuit, an output voltage detector for detecting an output voltage of the DC power supply circuit, a DC power supply control circuit for controlling the output voltage of the DC power supply circuit to a predetermined voltage according to a detection result of the output voltage detector, and an output voltage Based on the detection result of the detection unit, it is determined whether or not the output voltage of the DC power supply circuit has exceeded a predetermined overvoltage higher than the predetermined voltage, and when the predetermined overvoltage is exceeded, the operation of the DC power supply control circuit is stopped for a certain period of time. An abnormality determining unit that causes the time to be accumulated and a time unit that accumulates time corresponding to the operation time of the DC power supply control circuit, and at least a DC power supply control circuit when the time counted by the time measuring unit exceeds a predetermined time Power supply, characterized in that the predetermined time from the start of the operation to stop the operation of the abnormality determination unit until passage.

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