JP2018110501A - Power supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To omit an insulation component required for monitoring a state of bypass means for protecting components of a power supply device.SOLUTION: A smoothing circuit 212 smooths a current output from a rectification circuit 211 to supply it to a voltage converter 202. A reduction circuit 215 reduces an inrush current is about to flow in the smoothing circuit 212. A bypass circuit 216 causes the inrush current to flow in the reduction circuit 215 during a first period in which the inrush current may be generated and bypasses a current that is about to flow in the reduction circuit 215 during a second period in which the inrush current is hardly generated. A recovery unit 240 is provided at a primary side of the voltage converter 202 to supply a recovery signal for normally recovering operation of the bypass circuit 216 to the bypass circuit 216 when the bypass circuit 216 does not normally operate.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a power supply device.

  A power supply device that converts alternating current supplied from an external power source such as a commercial power source into direct current may be provided with a reduction circuit for reducing inrush current. A simple reduction circuit is formed by a resistance element. However, as long as an external power supply is connected, current flows through the reduction circuit, and power consumption by the reduction circuit becomes a problem. Thus, by providing a relay in parallel with the reduction circuit, the power consumed by the reduction circuit can be reduced.

  However, since the relay has a mechanical movable part, it tends to cause a malfunction as compared with a semiconductor switch. According to Patent Document 1, it is proposed that when the CPU detects a malfunction of the relay, the relay is repeatedly turned on / off to recover the relay.

Japanese Patent Laid-Open No. 11-273524

  According to Patent Document 1, there is a possibility that the relay recovers by executing the recovery operation when the relay malfunctions. However, in Patent Document 1, the CPU is provided on the secondary side of the transformer. However, since the relay is provided on the primary side, an insulating component such as a photocoupler for connecting the CPU and the relay is required. End up. Therefore, an object of the present invention is to omit an insulating component necessary for monitoring the state of the bypass means for protecting the component of the power supply device.

According to the present invention, for example,
Conversion means for converting the primary side voltage and outputting the secondary side voltage;
A rectifying means connected to an AC power supply, provided on the primary side of the conversion means, for rectifying the AC supplied from the AC power supply;
A smoothing means connected to the rectifying means and smoothing the current output from the rectifying means and supplying the smoothed current to the converting means;
A reducing means connected to the smoothing means for reducing an inrush current flowing through the smoothing means;
The rush current is passed through the reduction means in a first period that is connected in parallel to the reduction means, has a resistance value smaller than the resistance value of the reduction means, and can generate the rush current. A bypass means for bypassing a current that is about to flow to the reducing means in the second period in which current is difficult to occur;
A recovery signal is provided on the primary side of the conversion means, is supplied with a voltage generated by the conversion means and operates, and when the bypass means does not operate normally, a recovery signal for recovering the operation of the bypass means normally. There is provided a power supply device comprising recovery means for supplying to the bypass means.

  According to the present invention, since the recovery means for recovering the bypass means is provided on the primary side of the conversion means, the insulating component can be omitted.

Illustration showing electrical equipment Block diagram showing the power supply Circuit diagram showing power supply Diagram showing various waveforms Diagram showing various waveforms Block diagram showing the power supply Diagram showing various waveforms

  FIG. 1 shows an example of an electrical device in which the power supply device 150 is used. The electric apparatus in this example is an electrophotographic image forming apparatus 100 that reads a document by a document reading device 120 and copies the document on a sheet. Note that this embodiment can be applied to any electrical device that uses the power supply apparatus 150 that converts alternating current supplied from an external power source into direct current. The electrical device may be an ink jet printer or other home appliance.

  The image forming apparatus 100 includes four image forming stations that form toner images using toners of yellow, magenta, cyan, and black. “Y”, “m”, “c”, and “k” given at the end of the reference sign mean yellow, magenta, cyan, and black, respectively, and are omitted in the description common to the four colors.

  The photosensitive drum 101 is an image carrier that is uniformly charged by a charging roller of the image forming apparatus 102. The exposure device 103 exposes the surface of the photosensitive drum 101 according to the image data to form an electrostatic latent image. The developing device of the image forming apparatus 102 develops the toner by attaching toner to the electrostatic latent image to form a toner image. The primary transfer roller 104 transfers the toner image to the intermediate transfer belt 105.

  The pickup roller 109 picks up the sheet P stored in the paper feed cassette 108 and sends it out to the conveyance path. The pair of paper feed rollers 110 further conveys the sheet P sent out by the pickup roller 109 to the downstream side in the conveyance path. Here, the side closer to the paper feed cassette 108 in the transport direction of the sheet P is the upstream side, and the side closer to the paper discharge roller 114 is the downstream side. The conveyance roller pair 113 further conveys the sheet P downstream. The registration roller pair 111 is a roller pair that synchronizes the timing at which the sheet P arrives at the secondary transfer portion and the timing at which the toner image arrives at the secondary transfer portion. The secondary transfer roller pair 107 disposed in the secondary transfer portion secondarily transfers the toner image onto the sheet P. The fixing device 112 fixes the toner image on the sheet P by applying heat and pressure to the sheet P and the toner image. The paper discharge roller 114 discharges the sheet P to the paper discharge tray.

  The power supply device 150 supplies a DC voltage to a plurality of arithmetic devices that control the image forming apparatus 100, motors, sensors, cooling fans, high-voltage power supplies, and the like. The power supply apparatus 150 may include not only an AC / DC converter but also a plurality of DC / DC converters.

<Power supply unit>
FIG. 2 is a block diagram showing a basic circuit provided in the power supply device 150. The power supply device 150 is divided into a primary side and a secondary side with the voltage converter 202 as a boundary, and the primary side and the secondary side are insulated.

  On the primary side of the power supply device 150, the rectifier circuit 211 is connected to the external power supply 201, and is a circuit that rectifies the alternating current supplied from the external power supply 201. The smoothing circuit 212 is connected to the rectifier circuit 211 and is a circuit that smoothes the output of the rectifier circuit 211.

  The voltage generation circuit 213 is a circuit that generates a power supply voltage Vcc ′ to be supplied to the power supply controller IC 1 or the like when the power supply apparatus 150 is activated. The switch circuit 214 is a circuit that switches the primary side voltage (primary side current) applied to the primary side of the voltage converter 202.

  On the secondary side of the power supply device 150, the smoothing circuit 222 is a circuit that smoothes the secondary side voltage (secondary side current) generated on the secondary side of the voltage converter 202. The voltage detection circuit 223 detects the output voltage Vout from the smoothing circuit 222 and applies a voltage proportional to the output voltage Vout to the feedback circuit 231. The feedback circuit 231 has a function of insulating the primary side and the secondary side and supplies a voltage Vfb proportional to the output voltage Vout to the power supply controller IC1. The power supply controller IC1 is a control unit that switches the switch circuit 214 according to the fed back voltage Vfb so that the output voltage Vout becomes the target voltage. The voltage generation circuit 210 is a circuit that generates a power supply voltage Vcc to be supplied to the power supply controller IC 1 and the like based on the power supplied from the voltage converter 202. When the power supply voltage Vcc rises to a specified voltage, the power supply controller IC1 cuts off the power supply voltage Vcc 'supplied from the voltage generation circuit 213 and operates with the power supply voltage Vcc. This is because the voltage generation circuit 210 is more efficient than the voltage generation circuit 213.

  Incidentally, a large inrush current may flow through the smoothing circuit 212 when the power supply device 150 is started. The reduction circuit 215 protects the smoothing circuit 212 and the like by reducing the inrush current. As is apparent from FIG. 2, the power supplied from the external power supply 201 is consumed by the reduction circuit 215 not only when the power supply apparatus 150 is started but also after the power supply apparatus 150 transitions to a steady state. Therefore, a bypass circuit 216 is provided in parallel with the reduction circuit 215 in order to reduce power consumption in the power supply device 150. The bypass circuit 216 causes the current to flow through the reduction circuit 215 during the first period when the inrush current can occur, and does not flow the current through the reduction circuit 215 during the second period when the inrush current is difficult to occur. It is a circuit that operates so as to be removed.

  The bypass circuit 216 can be configured by a semiconductor switch, an electromagnetic relay, or the like. In particular, when a switch element having a mechanical movable part such as an electromagnetic relay is used for the bypass circuit 216, the mechanical movable part may not temporarily operate. In such a case, when the recovery unit 240 executes the recovery operation, the bypass circuit 216 operates normally again. The recovery unit 240 detects whether the bypass circuit 216 is operating normally by monitoring the current (voltage Vr1) flowing through the reduction circuit 215.

  The delay circuit 241 is a circuit that delays the recovery operation so that the recovery unit 240 does not execute the recovery operation during a period in which an inrush current may occur. For example, the delay circuit 241 may include a time constant circuit that delays the time during which the voltage Vr1 of the reduction circuit 215 is transmitted to the operation detection circuit 242. The operation detection circuit 242 is a circuit that detects a current flowing through the reduction circuit 215. This current is converted into a voltage and detected. That is, the operation detection circuit 242 is a circuit that detects the voltage Vr1 generated in the reduction circuit 215. If the voltage Vr1 (detection voltage Vsns) is higher than the threshold voltage, the operation detection circuit 242 determines that the bypass circuit 216 is not operating normally and causes the recovery unit 240 to perform a recovery operation. If the voltage Vr1 (detection voltage Vsns) is equal to or lower than the threshold voltage, the operation detection circuit 242 determines that the bypass circuit 216 is operating normally and does not cause the recovery unit 240 to perform the recovery operation. The switch circuit 243 is a circuit that controls whether or not the recovery circuit 245 generates a recovery signal according to the detection result of the operation detection circuit 242. The switch circuit 243 does not operate the recovery circuit 245 if the bypass circuit 216 is operating normally. On the other hand, the switch circuit 243 activates the recovery circuit 245 if the bypass circuit 216 is not operating normally. The recovery circuit 245 is a circuit that does not output a recovery signal to the switch circuit 246 if the bypass circuit 216 is operating normally, and outputs a recovery signal to the switch circuit 246 if the bypass circuit 216 is not operating normally. . That is, the recovery circuit 245 is a recovery signal generation circuit. The switch circuit 246 is a circuit that attempts to recover the bypass circuit 216 by intermittently supplying the power supply voltage Vcc to the bypass circuit 216 based on the recovery signal. Many of the causes of non-conduction of electromagnetic relays are contamination by foreign matter between the contacts. Therefore, by repeatedly turning on / off the contact portion, the foreign matter moves from the contact portion, the foreign matter is crushed, or the foreign matter is burned out by arc discharge generated at the contact portion. As a result, the contact portion becomes conductive again. The operation limiting circuit 244 is an optional circuit for controlling the period during which the recovery operation of the recovery circuit 245 is continuously executed to a certain period. Note that the operation limiting circuit 244 may be connected to the subsequent stage of the recovery circuit 245 and block or terminate the recovery signal.

<Circuit diagram>
FIG. 3 is a circuit diagram of the power supply device 150. The diode bridge D1 constitutes a rectifier circuit 211 and rectifies an AC voltage input from an external power source 201 that is a commercial AC power source. The primary electrolytic capacitor C1 constitutes a smoothing circuit 212 that smoothes the voltage rectified by the diode bridge D1. For example, if the external power supply 201 is a commercial power supply that supplies an AC voltage of 100V, the primary electrolytic capacitor C1 is charged such that the voltage Vc of the primary electrolytic capacitor C1 is 141V that is the peak voltage of the AC voltage. The charging current of the primary electrolytic capacitor C1 is a current restricted by the resistance value of the reduction resistor R1 that constitutes the reduction circuit 215. Thus, since the inrush current is reduced by the reduction resistor R1, the primary electrolytic capacitor C1 is protected from the inrush current.

  The zener diode ZD1 and the resistor R2 connected to the power controller IC1 constitute a voltage generation circuit 213, and supplies the operating voltage Vcc 'to the power controller IC1. The power supply controller IC 1 supplied with the operating voltage Vcc ′ starts outputting a gate signal to the FET Q 1 constituting the switch circuit 214. FET is an abbreviation for field effect transistor.

  The FET Q1 applies a voltage to the primary winding T1a of the transformer T1 constituting the voltage converter 202 while switching in accordance with the gate signal. The secondary winding T1b and the auxiliary winding T1c are wound around the same core as the primary winding T1a. Voltages corresponding to the turn ratio with respect to the primary winding T1a are generated in the secondary winding T1b and the auxiliary winding T1c, respectively.

  The voltage generated in the secondary winding T1b is smoothed by the smoothing circuit 222 constituted by the diode D2 and the electrolytic capacitor C2. The output voltage Vout of the smoothing circuit 222 is supplied to the load of the electric device. A circuit including the resistors R4, R5, R6, the capacitor C3, and the shunt regulator IC2 constitutes a part of the voltage detection circuit 223 and the feedback circuit 231. When the output voltage Vout is higher than the target voltage, the current flowing through the resistor R3 and the light emitting diode PH1a increases. Conversely, when the output voltage Vout is lower than the target voltage, the current flowing through the photodiode PH1a decreases. The light emitting diode PH1a emits light when a current flows, and turns on the phototransistor PH1b in an electrically insulated state. Note that although the light emitting diode PH1a and the phototransistor PH1b are illustrated at positions apart from each other in FIG. 3, these are photocouplers contained in a single package and function as the feedback circuit 231.

  A terminal of the power supply controller IC1 to which the phototransistor PH1b, the resistor R6, and the capacitor C4 are connected is a constant current source. The voltage at this terminal is determined by the on-resistance of the phototransistor PH1b. This terminal voltage is the feedback voltage Vfb. A reference voltage Vtar (not shown) to be compared with the feedback voltage Vfb exists inside the power supply controller IC1. The power supply controller IC1 controls the gate signal output to the FET Q1 so as to reduce the deviation (difference) between the feedback voltage Vfb and the reference voltage Vtar.

  On the other hand, the voltage generated in the auxiliary winding T1c is applied to the voltage generation circuit 210. As shown in FIG. 4, the voltage generation circuit 210 includes a diode D3, a resistor R7, an electrolytic capacitor C5, a transistor Tr1, a resistor R8, and a Zener diode ZD2, and the transistor Tr1 forms a voltage generation circuit 210. The voltage generated in the auxiliary winding T1c is smoothed by the diode D3, the resistor R7, and the electrolytic capacitor C5. The transistor Tr1, the resistor R8, and the Zener diode ZD2 operate so that the emitter output of the transistor Tr1 becomes a constant power supply voltage Vcc. The power supply voltage Vcc is supplied to the power supply controller IC1. Receiving the supply of the power supply voltage Vcc, the power supply controller IC1 cuts off the supply of the power supply voltage Vcc 'generated by the Zener diode ZD1 and the resistor R2.

Bypass operation The power supply voltage Vcc is used as a drive voltage for the relay RL1 constituting the bypass circuit 216. The power supply voltage Vcc switches the transistor Tr5 from off to on via the resistor R16. The transistor Tr5 forms a switch circuit 246 through the resistor R16. When the transistor Tr5 is turned on, a current flows through the drive coil of the relay RL1, and the contact of the relay RL1 is connected. As a result, the current flowing through the reduction resistor R1 constituting the reduction circuit 215 bypasses the reduction resistor R1. The reduction resistor R1 may be a resistor with a thermal fuse. Since no current flows through the reduction resistor R1, power consumption at the reduction resistor R1 is reduced. Thus, when the charging of the primary electrolytic capacitor C1 is completed, the power supply controller IC1 starts supplying the gate signal to the FET Q1, the power supply voltage Vcc is supplied, and the bypass operation by the relay RL1 is started.

Recovery operation By the way, even if a current flows through the drive coil of the relay RL1, the contact may not be conducted. For example, if foreign matter or the like adheres between the contacts, the contacts do not conduct. In this case, the recovery operation is executed.

  If the contact does not conduct even when a current is passed through the drive coil of the relay RL1, the current flows through the reduction resistor R1. By supplying power to the load, the voltage Vc of the primary electrolytic capacitor C1 decreases. When the commercial power supply voltage exceeds the voltage Vc, a current flows. A voltage Vr1 obtained by multiplying the current value by the resistance value of the reduction resistor R1 is generated in the reduction resistor R1. The voltage Vr1 is smoothed by the resistor R9 and the capacitor C6. The voltage dividing circuit formed by the resistor R9 and the resistor R10 divides the voltage Vr1 into the detection voltage Vsns. The detection voltage Vsns is the base voltage of the transistor Tr2. Thus, the detection voltage Vsns depends on the resistor R10 and becomes a voltage proportional to the voltage Vr1. The resistor R9 and the capacitor C6 form the delay circuit 241 described above. The delay circuit 241 is a time constant circuit that delays the timing at which the voltage Vsns is applied to the transistor Tr2. That is, the time constants of the resistor R9 and the capacitor C6 are designed to be sufficiently large so as not to turn on the transistor Tr2 during the period when the inrush current is generated. The resistance value of the resistor R10 is designed to turn on the transistor Tr2 when the average voltage of the voltage Vr1 generated in the reduction resistor R1 is equal to or higher than a predetermined threshold. That is, this threshold is set to a value that turns on the transistor Tr2 when the voltage Vr1 rises due to the malfunction of the relay RL1, and does not turn on the transistor Tr2 if the relay RL1 is operating normally. Yes. Thus, the resistor R9, the resistor R10, and the transistor Tr2 function as the operation detection circuit 242. In addition, this threshold value is designed so that the thermal fuse of the reduction resistor R1 does not blow even when a constant current flows through the reduction resistor R1. This prevents malfunction of the transistor Tr2.

  FIG. 4 is a diagram for explaining the relationship among the AC voltage Vac, the load current Iload, the voltage Vr1, and the detection voltage Vsns. The voltage Vr1 of the reduction resistor R1 increases depending on the load current Iload of the electric device. The detection voltage Vsns follows the change of the reduction resistor R1 voltage Vr1 with a delay. This means that even if an inrush current occurs, the relay RL1 does not turn on immediately, and the inrush current flows to the reduction resistor R1.

  When the transistor Tr2 is turned on, a voltage generated by dividing the power supply voltage Vcc by the voltage dividing circuit formed by the resistors R11 and R12 is applied to the transistor Tr3. As a result, the transistor Tr3 is switched from OFF to ON, and the power supply voltage Vcc is supplied to the Schmitt inverter IC3 via the transistor Tr3. The transistor Tr3 functions as the switch circuit 243. The Schmitt inverter IC3 is a logic IC whose output changes with hysteresis with respect to a change in input voltage. The oscillation circuit formed by the Schmitt inverter IC3, the resistor R13, and the capacitor C7 oscillates to generate a rectangular wave. The Schmitt inverter IC3, the resistor R13, and the capacitor C7 constitute a recovery circuit 245. The oscillation cycle of the recovery circuit 245 is sufficiently longer than the operation time of the relay RL1 and sufficiently longer than the return time. In order to perform many recovery operations in a short time, the oscillation period is set to about 0.1 sec to 1 sec (eg, 500 ms). The output voltage of the Schmitt inverter IC3 turns on / off the transistor Tr4 via the resistors R14 and R15. The transistor Tr5 connected to the subsequent stage of the transistor Tr4 is turned on / off in conjunction with the on / off of the transistor Tr4. As a result, the current IRL flows through the drive coil of the relay RL1 at a constant period, and the relay RL1 is continuously turned on / off.

  FIG. 5A shows the relationship among commercial power supply voltage Vac, power supply voltage Vcc, detection voltage Vsns, and current IRL when relay RL1 is normal. FIG. 5B shows the relationship among the commercial power supply voltage Vac, the power supply voltage Vcc, the detection voltage Vsns, and the current IRL when the relay RL1 is not normal. If relay RL1 is normal as shown in FIG. 5A, power supply voltage Vcc is generated in response to the start of supply of commercial power supply voltage Vac, current IRL flows through the drive coil of relay RL1, and relay RL1 is turned on. At this time, the detection voltage Vsns proportional to the voltage Vr1 across the reduction resistor R1 is approximately 0V.

  As shown in FIG. 5B, when the relay RL1 causes a conduction failure, the relay RL1 does not conduct when the current IRL flows through the drive coil. Therefore, the detection voltage Vsns does not become 0V but is maintained at a higher voltage. When an electric device that is a load starts operation, the load current increases. When the load current increases, the current flowing through the reduction resistor R1 also increases, so that the detection voltage Vsns increases. When the detection voltage Vsns increases, the transistor Tr2 is turned on, and energization of the drive coil of the relay RL1 is periodically executed. When the conduction of the relay RL1 is restored by repeating energization of the drive coil, the detection voltage Vsns drops to 0V. This is because the relay RL1 bypasses the current flowing through the drive coil. When the detection voltage Vsns falls below the threshold value, the transistors Tr2 and Tr3 are turned off, so that the power supply voltage Vcc is not supplied to the recovery circuit 245 and the recovery circuit 245 stops. As a result, a normal drive current corresponding to the power supply voltage Vcc flows through the drive coil of the relay RL1.

  Thus, according to the present embodiment, the recovery operation is performed by the recovery unit 240 even if the relay RL1 of the bypass circuit 216 malfunctions. As shown in FIGS. 2 and 3, the recovery unit 240 is provided on the primary side. Therefore, the relay RL1 can perform malfunction detection and recovery operations without using an arithmetic IC such as a CPU provided on the secondary side. This will improve the protection against inrush current.

  A power factor correction circuit (PFC) may be provided between the diode bridge D1 and the primary electrolytic capacitor C1. In this case as well, the above embodiment can be applied. When the power factor correction circuit (PFC) is introduced, the waveform of the current flowing through the reduction resistor R1 changes. However, since the resistor R9 and the capacitor C6 are filters having a time constant capable of sufficiently smoothing commercial alternating current, the above embodiment can be applied even if a power factor correction circuit (PFC) is introduced.

<Operation restriction circuit>
FIG. 6 is a circuit diagram of the power supply device 150. Compared to FIG. 3, an operation limiting circuit 244 is added in FIG. 6, but other circuit configurations are shared. The operation limiting circuit 244 includes a resistor R17, a resistor R18, a capacitor C8, and a transistor Tr6, and limits the number of ON / OFF operations (recovery operation period) of the relay RL1.

  FIG. 7A shows the relationship among the commercial power supply voltage Vac, the power supply voltage Vcc, the detection voltage Vsns, the current IRL, and the base voltage Vbe when the relay RL1 is normal. FIG. 7B shows the relationship among the commercial power supply voltage Vac, the power supply voltage Vcc, the detection voltage Vsns, and the current IRL when the relay RL1 is recovered by the recovery operation. FIG. 7C shows the relationship among the commercial power supply voltage Vac, the power supply voltage Vcc, the detection voltage Vsns, and the current IRL when the relay RL1 is recovered by the recovery operation.

  As shown in FIG. 7A, when the relay RL1 is normal, the detection voltage Vsns for the reduction resistor R1 is almost 0V. This is as described with reference to FIG. 5A. Further, since the detection voltage Vsns does not exceed the threshold value, the transistors Tr2 and Tr3 remain off, and the base voltage Vbe does not exceed the operation threshold value. That is, the transistor Tr6 is also kept off.

  As shown in FIG. 7B, when the relay RL1 malfunctions, the detection voltage Vsns for the reduction resistor R1 increases, so that the recovery operation is started. This point is as described with reference to FIG. 5B. When it is detected that the relay RL1 has malfunctioned, the transistors Tr2 and Tr3 are turned on, and charging of the capacitor C8 is started through the resistor R17. The voltage across the capacitor C8 is the base voltage Vbe. Here, the time constants of the resistor R17, the resistor R18, and the capacitor C8 are set to be sufficiently longer than the oscillation cycle of the recovery circuit 245. This is because the period during which the relay RL1 continuously executes the recovery operation is set to be a predetermined period or longer. When the base voltage Vbe generated by dividing by the resistors R17 and R18 becomes equal to or higher than the threshold voltage, the transistor Tr6 is turned on. As shown in FIG. 7B, when the relay RL1 recovers before the transistor Tr6 is turned on, the transistors Tr2 and Tr3 are turned off and the charging of the capacitor C8 is stopped. That is, the increase of the base voltage Vbe ends. Thereafter, the electric charge of the capacitor C8 is discharged through the resistor R18.

  As shown in FIG. 7C, the relay RL1 may not recover even if the recovery operation is executed. The base voltage Vbe increases in proportion to the time (elapsed time) during which the recovery circuit 245 continuously executes the recovery operation. That is, the base voltage Vbe increases as the charging of the capacitor C8 proceeds. Eventually, when the base voltage Vbe becomes equal to or higher than the threshold value, the transistor Tr6 is turned on. When the transistor Tr6 is turned on, the output of the recovery signal by the recovery circuit 245 is invalidated. That is, the rectangular wave signal output from the Schmitt inverter IC3 is guided to the ground and terminated. As a result, the transistor Tr4 is turned off and the transistor Tr5 is turned on. As a result, the power supply voltage Vcc is continuously applied to the relay RL1, and a drive current continuously flows through the drive coil.

  Thus, by limiting the execution time of the recovery operation to a certain time or less, it is possible to limit the generation time of the driving sound of the relay RL1 accompanying the recovery operation to a certain time or less.

<Summary>
As described with reference to FIGS. 2 and 3, the voltage converter 202 and the transformer T <b> 1 are an example of a conversion unit that converts a primary side voltage and outputs a secondary side voltage. The rectifier circuit 211 is an example of a rectifier that is connected to an AC power source and provided on the primary side of the voltage converter 202 and rectifies the AC supplied from the AC power source. The smoothing circuit 212 is an example of a smoothing unit that is connected to the rectifying circuit 211 and smoothes the current output from the rectifying circuit 211 and supplies the smoothed current to the voltage converter 202. The reduction circuit 215 is an example of a reduction unit that is connected to the smoothing circuit 212 and reduces an inrush current that tends to flow to the smoothing circuit 212. The bypass circuit 216 is connected in parallel to the reduction circuit 215 and has a resistance value smaller than the resistance value of the reduction circuit 215. The bypass circuit 216 bypasses the current that flows through the reduction circuit 215 during the first period in which the inrush current can occur and bypasses the current that flows through the reduction circuit 215 during the second period during which the inrush current is unlikely to occur. It is an example. The recovery unit 240 is provided on the primary side of the voltage converter 202 and is supplied with a voltage generated by the voltage converter 202 and operates. The recovery unit 240 is an example of recovery means for supplying a recovery signal for normally recovering the operation of the bypass circuit 216 to the bypass circuit 216 when the bypass circuit 216 does not operate normally. As described above, since the recovery unit 240 for recovering the bypass circuit 216 is provided on the primary side of the voltage converter 202, an insulating component for transmitting the state of the bypass circuit 216 to the secondary side is omitted. Is possible.

  As shown in FIG. 3 and the like, the bypass circuit 216 may be an electromagnetic relay RL1 that is turned on or off according to a control signal. This is because there are many cases where the recovery is performed by the recovery operation in a switch mechanism having a mechanical movable part such as the electromagnetic relay RL1.

  When the electromagnetic relay RL1 does not operate normally, the recovery unit 240 supplies the electromagnetic relay RL1 with a recovery signal that intermittently operates the movable portion of the electromagnetic relay RL1. The cause of the malfunction of the electromagnetic relay RL1 is mainly that foreign matter enters between the contacts. Therefore, the removal of the foreign matter is promoted by intermittently operating the movable portion of the electromagnetic relay RL1.

  The recovery signal is a signal that repeats a high level (on) and a low level (off). This signal is a rectangular drive current IRL as shown in FIG. 5B. The high level duration is longer than the operating time of the electromagnetic relay RL1. The low level time is longer than the return time of the electromagnetic relay. Thereby, the recovery of the relay RL1 is promoted.

  The operation detection circuit 242 is an example of a detection unit that detects that the bypass circuit 216 is not operating normally based on the voltage applied to the reduction circuit 215. This voltage is proportional to the current flowing through the reduction circuit 215. Therefore, the operation detection circuit 242 functions as a voltage detection circuit or a current detection circuit. When the operation detection circuit 242 detects that the bypass circuit 216 is not operating normally, the recovery unit 240 supplies a recovery signal to the bypass circuit 216. As shown in FIG. 5B and the like, if the bypass circuit 216 does not operate normally, the detection voltage Vsns indicating the voltage applied to the reduction circuit 215 increases. Therefore, the operation detection circuit 242 can detect whether the bypass circuit 216 is operating normally by monitoring the detection voltage Vsns.

  The operation detection circuit 242 is an example of a detection unit that detects a voltage applied to the reduction circuit 215. The switch circuit 243 operates the recovery circuit 245 of the recovery unit 240 if the voltage detected by the operation detection circuit 242 is equal to or higher than the threshold, and recovers not to operate the recovery circuit 245 if the detected voltage is not higher than the threshold. It is an example of a control means. As described above, the operation detection circuit 242 monitors the detection voltage Vsns, so that the recovery circuit 245 can be appropriately operated.

  The switch circuit 243 supplies the operating voltage to the recovery circuit 245 if the detection voltage Vsns detected by the operation detection circuit 242 is equal to or higher than the threshold, and supplies the operating voltage to the recovery circuit 245 if the detection voltage Vsns is not higher than the threshold. A switch element that is not supplied may be used. Such a switch element can be realized by the transistors Tr2 and Tr3.

  The recovery circuit 245 is an example of a rectangular wave generating unit that generates a rectangular wave having a fixed period as a recovery signal. Accordingly, by supplying a rectangular wave with a fixed period to the drive coil of the relay RL1, the drive coil is intermittently excited to vibrate the movable part, thereby facilitating the removal of foreign matter.

  The operation limiting circuit 244 is an example of a limiting unit that limits a period during which the recovery circuit 245 continuously outputs the recovery signal to a certain period. When the recovery signal is supplied, the bypass circuit 216 generates driving sound. Therefore, by limiting the period in which the recovery signal is continuously output to a certain period, it is possible to limit the generation period of the drive sound.

  As shown in FIG. 6, the operation limiting circuit 244 is output from the recovery circuit 245 when the voltage of the capacitor C8 charged while the operating voltage Vcc is supplied to the recovery circuit 245 and the voltage of the capacitor C8 exceeds a threshold value. There may be provided a switch element for blocking the recovery signal. This switch element can be realized by the transistor Tr6. Note that a switch element that cuts off the supply of the operating voltage Vcc to the recovery circuit 245 when the voltage of the capacitor C8 becomes equal to or higher than the threshold value may be employed.

  The smoothing circuit 212 may include a primary electrolytic capacitor C1 that is a smoothing capacitor. As shown in FIGS. 4 and 5A, the delay circuit 241 is a delay unit that delays the operation of the bypass circuit 216 so that the bypass circuit 216 starts the bypass operation after the first period during which the inrush current can occur. It is an example. The delay circuit 241 may be a time constant circuit including a resistor R9 and a capacitor C9. With such a simple circuit configuration, the bypass circuit 216 can be operated after a first period during which an inrush current can occur. That is, the inrush current is easily reduced by the reduction circuit 215 in the first period in which the inrush current can occur.

  As shown in FIG. 3 and the like, the FET Q1 is an example of switching means for switching the current flowing in the primary winding of the voltage converter 202. The feedback circuit 231 is an example of feedback means that feeds back the secondary side voltage generated in the secondary winding of the voltage converter 202 to the primary side of the voltage converter 202. The power supply controller IC1 is an example of switching control means for controlling the FET Q1 according to the difference between the voltage Vfb fed back by the feedback circuit 231 and the target voltage. The voltage generation circuit 210 is an example of voltage generation means for generating the power supply voltage Vcc of the power supply controller IC1 and the bypass circuit 216 based on the voltage generated in the auxiliary winding of the voltage converter 202.

  Switch circuit 246 has a first switch element that supplies power supply voltage Vcc to bypass circuit 216 when power supply voltage Vcc is supplied and does not supply power supply voltage Vcc to bypass circuit 216 when power supply voltage Vcc is not supplied. May be. The first switch element may be realized by a transistor Tr5, for example. In addition, the switch circuit 246 may include a second switch element that turns on the transistor Tr5 when no recovery signal is input and intermittently switches the transistor Tr5 according to the recovery signal when the recovery signal is input. . The second switch element may be realized by the transistor Tr4.

DESCRIPTION OF SYMBOLS 150 ... Power supply device, 202 ... Voltage converter, 211 ... Rectifier circuit, 212 ... Smoothing circuit, 215 ... Reduction circuit, 216 ... Bypass circuit, 240 ... Recovery part

Claims (15)

Conversion means for converting the primary side voltage and outputting the secondary side voltage;
A rectifying means connected to an AC power supply, provided on the primary side of the conversion means, for rectifying the AC supplied from the AC power supply;
A smoothing means connected to the rectifying means and smoothing the current output from the rectifying means and supplying the smoothed current to the converting means;
A reducing means connected to the smoothing means for reducing an inrush current flowing through the smoothing means;
The rush current is passed through the reduction means in a first period that is connected in parallel to the reduction means, has a resistance value smaller than the resistance value of the reduction means, and can generate the rush current. A bypass means for bypassing a current that is about to flow to the reducing means in the second period in which current is difficult to occur;
A recovery signal is provided on the primary side of the conversion means, is supplied with a voltage generated by the conversion means and operates, and when the bypass means does not operate normally, a recovery signal for recovering the operation of the bypass means normally. And a recovery unit that supplies the bypass unit.   The power supply apparatus according to claim 1, wherein the bypass unit is an electromagnetic relay that is turned on or off according to a control signal.   3. The power supply according to claim 2, wherein the recovery means supplies the recovery signal that intermittently operates the movable portion of the electromagnetic relay to the electromagnetic relay when the electromagnetic relay does not normally operate. apparatus.   The recovery signal is a signal that repeats a high level and a low level, the high level duration is longer than the operation time of the electromagnetic relay, and the low level time is longer than the return time of the electromagnetic relay. The power supply device according to claim 3. Further comprising detecting means for detecting that the bypass means is not operating normally based on the voltage applied to the reducing means;
5. The recovery means supplies the recovery signal to the bypass means when the detection means detects that the bypass means is not operating normally. Power supply. Detecting means for detecting a voltage applied to the reducing means;
A recovery control means for operating the recovery means if the voltage detected by the detection means is greater than or equal to a threshold value, and not operating the recovery means if the voltage detected by the detection means is not greater than or equal to the threshold value;
The power supply device according to claim 1, further comprising:   The recovery control means supplies an operating voltage to the recovery means if the voltage detected by the detection means is greater than or equal to a threshold, and to the recovery means if the voltage detected by the detection means is not greater than or equal to the threshold. The power supply device according to claim 6, wherein the power supply device is a switch element that does not supply an operating voltage.   The power supply apparatus according to claim 1, wherein the recovery unit includes a rectangular wave generation unit that generates a rectangular wave having a fixed period as the recovery signal.   9. The power supply apparatus according to claim 1, further comprising a limiting unit that limits a period during which the recovery unit continuously outputs the recovery signal to a certain period. The limiting means is
A capacitor that is charged while operating voltage is supplied to the recovery means;
The switch element that cuts off the supply of the operating voltage to the recovery means when the voltage of the capacitor becomes a threshold value or cuts off the recovery signal output from the recovery means. 9. The power supply device according to 9.   The power supply device according to claim 1, wherein the smoothing unit includes a smoothing capacitor.   12. The delay means according to claim 1, further comprising delay means for delaying the operation of the bypass means so that the bypass means starts a bypass operation after the first period during which the inrush current can occur. The power supply device according to any one of the above.   The power supply apparatus according to claim 12, wherein the delay means is a time constant circuit including a resistor and a capacitor. Switching means for switching a current flowing in the primary winding of the conversion means;
Feedback means for feeding back a secondary side voltage generated in the secondary winding of the conversion means to the primary side of the conversion means;
Switching control means for controlling the switching means according to the difference between the voltage fed back by the feedback means and the target voltage;
Voltage generating means for generating a power supply voltage for the switching control means and the bypass means based on a voltage generated in the auxiliary winding of the converting means;
14. The power supply device according to claim 1, comprising: When the power supply voltage is supplied, the power supply voltage is supplied to the bypass means, and when the power supply voltage is no longer supplied, the first switch element that does not supply the power supply voltage to the bypass means;
A second switch element that turns on the first switch element when the recovery signal is not input and switches the first switch element on and off in response to the recovery signal when the recovery signal is input; The power supply device according to claim 14.