JP2005210809A - Electrical equipment power supply - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power supply device of an electric apparatus reduced in circuit scale and manufacturing cost using a single resistor both as rush current prevention resistors for preventing rush currents, in the power supply device equipped with a main power supply circuit and a standby power supply circuit. <P>SOLUTION: A standby current is fed to the standby power supply circuit 30 from an AC power supply 1 via the rush current prevention resistor 2. When a power supply switch 3-1 is turned on from a standby state, a temporary excessive overcurrent (rush current) flows in a rectifying and smoothing circuit of the main power supply circuit 20 from the AC power supply 1 via the rush current prevention resistor 2, but the excessive overcurrent is restrained by the resistor 2, and a diode that constitutes a rectifying circuit 4 is protected. When the charging voltage of a smoothing capacitor 6 reaches a steady value, the excitation coil 5-2 of a short-circuiting switch means 5 is excited, a short-circuiting switch 5-1 is turned on, and power can be fed to the main power supply circuit 20 not via the resistor 2. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a power supply device having a main power supply circuit and a standby power supply circuit, and a power supply device for an electric device having a function of preventing a rush current when the main power supply is turned on.

  Conventionally, in a power supply circuit of a television receiver or the like, an AC voltage from a commercial AC power supply is input, and a DC voltage rectified and smoothed by a rectifier circuit is further stabilized by a switching-type stabilized DC power supply circuit. A DC voltage of a magnitude is generated and supplied to various electronic circuits in each part of the receiver.

  In a rectifier circuit in a power supply circuit of a television receiver or the like, a smoothing capacitor having a relatively large capacity is disposed to stabilize the input voltage when the power is turned on. For this reason, an excessive rush current flows at the start-up when the AC power supply voltage is applied. In order to prevent this, it is common practice to suppress excessive current only during startup using a resistor, and when the device enters a normal operating state from startup, both ends of the resistor are made conductive by switch elements. Thus, a voltage drop and power loss in the power supply line due to resistance are prevented from occurring.

  Conventionally, as such a rush current prevention circuit, for example, a circuit and a device described in Patent Document 1 have been proposed.

  In Patent Document 1, a power supply line from a DC power source to a device is provided with a series circuit of a resistor for preventing a rush current and a first switch element for turning on / off a DC input current. A second switch element is connected in parallel. And when starting normal operation from start-up or normal operation from standby, etc., first the first switch element is made conductive by the first signal from the device, and the rush current is suppressed by the rush current prevention resistor. In the state, power is supplied to a predetermined part of the apparatus. Thereafter, the second switch element is turned on by a second signal from the device, and power is continuously supplied to a predetermined portion of the device.

On the other hand, many power supply circuits for electrical devices such as television receivers are provided with two power supplies, a main power supply circuit and a standby power supply circuit. In such a power supply circuit, since the currents flowing at the time of starting are different between the two power supplies, rush current preventing resistors suitable for the rectifier circuits of the main power supply and the standby power supply are used.
JP 2000-152498 A

  However, Patent Document 1 does not describe a standby power source that is considered to be configured in the apparatus, each circuit of the main power source, and a configuration that is necessary when shifting from the standby state to the main power source operation. Further, in a conventional power supply circuit having two power supplies, that is, a main power supply circuit and a standby power supply circuit, a rush current preventing resistor is required for each of the two power supplies.

  Therefore, in view of the above-described problems, the present invention provides a power supply device having a main power supply circuit and a standby power supply circuit that combines a rush current prevention resistor for preventing a rush current, thereby reducing circuit scale and manufacturing cost. It is an object of the present invention to provide a power supply device for an electric device that can be reduced.

A power supply device for an electrical apparatus according to the present invention includes a rectifier circuit that rectifies a voltage from an AC power supply and a smoothing capacitor that smoothes the rectified voltage, and generates a DC power supply voltage for operating various electronic circuits in the apparatus. A main power circuit to
A main power switch means disposed between the AC power supply and the main power supply circuit for turning on / off the supply of the AC power supply voltage from the AC power supply to the main power supply circuit;
A standby power supply circuit that inputs the voltage from the AC power supply from a branch point on a power supply line connecting the AC power supply and the main power supply switch means, and rectifies to generate a standby DC power supply voltage;
A rush current preventing resistor disposed on a power supply line between the AC power supply and the branch point and suppressing a rush current generated when the main power switch means is turned on;
Connected in parallel to the rush current prevention resistor, and after the main power supply switch means is turned on, turns on when the output voltage of the main power supply circuit reaches a predetermined value and shorts both ends of the rush current prevention resistor. And a short-circuit switch means that is turned off when the predetermined value is not reached and opens both ends of the rush current prevention resistor.

  In such a configuration, a single rush current prevention resistor is also used, and a rectifier circuit for a main power source and a rectifier circuit for a standby power source are connected to the subsequent stage. In addition, after the main power supply circuit is started up, the rush current prevention resistor is short-circuited by a switch means for short-circuiting so that no current flows through the rush current prevention resistor during normal operation. Voltage drop and power loss can be prevented.

  According to the power supply device of the present invention, in the power supply circuit having the main power supply circuit and the standby power supply circuit, the circuit scale and the manufacturing can be achieved by using the configuration in which the rush current preventing resistor for preventing the rush current is used as one. Cost can be reduced.

 Embodiments of the invention will be described with reference to the drawings.

FIG. 1 shows a configuration diagram of a power supply device for an electrical apparatus according to a first embodiment of the present invention.
In FIG. 1, a power supply device is supplied with a commercial power supply voltage from an AC power supply 1 to generate a DC power supply voltage for a main power supply and a commercial AC power supply voltage from the AC power supply 1. A standby power supply circuit 30 for generating a standby DC power supply voltage; a series circuit of a rush current prevention resistor 2 and a main power supply switch means 3 interposed in a power supply line connecting the AC power supply 1 and the main power supply circuit 20; A microcomputer (hereinafter referred to as a microcomputer) 11 as a control circuit that operates using the standby DC power supply voltage from the standby power supply circuit 30 as an operation voltage and outputs a main power on / off signal, and a rush current prevention resistor 2 are provided. Short-circuit switch means 5 connected in parallel and capable of short-circuiting both ends of the resistor 2, and a main power supply switch for turning on / off the AC power supply to the main power supply circuit 20 The pitch means 3 on the basis of the main power on / off signal is configured by including a drive transistor 13 for driving. The AC power supply voltage to the standby power supply circuit 30 is supplied from series connection points (branch points) a and b between the rush current prevention resistor 2 and the main power supply switch means 3.

  The main power supply circuit 20 includes a main power supply rectifier circuit 4, a main power supply smoothing capacitor 6, and a stabilized DC power supply circuit 7.

  One output terminal of the AC power supply 1 is connected to one AC input terminal of the rectifier circuit 4 for the main power supply via the rush current preventing resistor 2 and the power switch 3-1 of the main power supply switch means 3 in series. . The other AC input terminal of the main power supply rectifier circuit 4 is connected to the other output terminal of the AC power supply 1. The rush current preventing resistor 2 is connected in parallel with a shorting switch 5-1 of the shorting switch means 5 for short-circuiting both ends of the resistor 2.

  The main power supply rectifier circuit 4 is constituted by a full-wave rectifier diode bridge, and an AC power supply voltage is input via a series circuit of a rush current preventing resistor 2 and a switch 3-1 of the main power supply switch means 3. Is full-wave rectified.

  A main power supply smoothing capacitor 6 for smoothing the rectified output voltage is connected to the + output terminal of the rectified voltage of the main power supply rectifier circuit 4. The smoothed voltage output from the main power supply smoothing capacitor 6 is input to the stabilized DC power supply circuit 7.

  The stabilized DC power supply circuit 7 is composed of a switching power supply circuit called a switching regulator, for example, and receives a smoothed voltage from the smoothing capacitor 6 to generate a stabilized DC voltage. The stabilized DC power supply circuit 7 outputs stabilized DC voltages of various sizes, for example, 8V, 11V, 25V, and 120V, according to the necessity of various electronic circuits in the electrical equipment in which the power supply circuit is used. It has come to be.

  On the other hand, the standby power supply circuit 30 includes a standby rectifier circuit 8, a standby smoothing capacitor 9, and a stabilized DC power supply circuit 10.

  A standby rectifier circuit 8 is connected to both ends of the AC power supply 1 via a rush current preventing resistor 2. The standby rectifier circuit 8 is composed of a full-wave rectifier diode bridge, and full-wave rectifies the AC power supply voltage supplied via the rush current prevention resistor 2.

  A standby smoothing capacitor 9 for smoothing the rectified output voltage is connected to the + output terminal of the rectified voltage of the standby rectifier circuit 4. The smoothed voltage output from the standby smoothing capacitor 9 is input to the stabilized DC power supply circuit 10.

  The stabilized DC power supply circuit 10 receives the smoothed voltage from the smoothing capacitor 9 and generates a stabilized DC voltage. The stabilized DC power supply circuit 10 is configured by a switching power supply circuit called a switching regulator, for example. The stabilized DC power supply circuit 10 outputs a stabilized DC voltage of 5V, for example.

  The stabilized DC voltage from the stabilized DC power supply circuit 10 is supplied as an operation voltage to the microcomputer 11 as a control circuit. For example, the microcomputer 11 generates various control signals in response to various commands from the operation means 12 and supplies them to various electronic circuits in the electrical equipment. For example, when the user performs a main power on / off operation with the operation means 12, the microcomputer 11 generates and outputs a main power on / off signal. The main power on / off signal from the microcomputer 11 is input to the base of the relay driving transistor 13.

  The main power switch means 3 is composed of an electromagnetic relay having a relay switch 3-1 and an exciting coil 3-2. One end of the exciting coil 3-2 is a reference via a collector / emitter path of a relay driving transistor 13. Connected to the potential point, the main power on / off signal from the microcomputer 11 is inputted to the base of the relay driving transistor 13, and the other end of the exciting coil 3-2 stabilizes the stabilized DC power circuit 10. It is connected to the DC voltage output terminal (5V), and DC 5V is supplied.

  In the configuration of FIG. 1, the main power switch means 3 is configured by an electromagnetic relay and is turned on / off by a control signal from the microcomputer 11. However, the main power switch means 3 is manually turned on / off instead of the electromagnetic relay. An operation power switch that can be turned off may be provided.

  On the other hand, the short-circuit switch means 5 is composed of an electromagnetic relay having a relay switch 5-1 and an exciting coil 5-2, and the relay switch 5-1 is connected in parallel to both ends of the rush current preventing resistor 2. One end of the exciting coil 5-2 is connected to a reference potential point, and the other end of the exciting coil 5-2 is connected to one of the stabilized DC voltage output terminals of the stabilized DC power supply circuit 7 (for example, the DC 11V output terminal). Connected.

  The switch 5-1 of the short-circuit switch means 5 is connected in parallel to the rush current prevention resistor 2, and after the switch 3-1 of the main power switch means 3 is turned on, the output voltage of the stabilized DC power supply circuit 7 is When it reaches a predetermined value (for example, 10V), it is turned on by the electromagnetic force of the exciting coil 3-2 to short-circuit both ends of the rush current preventing resistor 2. Accordingly, the switch 5-1 of the short-circuit switch means 5 is turned off when the output voltage of the stabilized DC power supply circuit 7 does not reach the predetermined value (10V) after the switch 3-1 of the main power supply switch means 3 is turned on. doing.

  1 may be constituted by an infrared remote controller and its light receiving circuit in addition to the key input means of the operation panel disposed in the casing of the electric device.

FIG. 2 shows a timing chart for explaining the operation of this embodiment.
When an instruction to turn on the main power source is given by the operating means 12 at the time of starting the electric device, a main power on signal (for example, a high level signal) is output from the microcomputer 11 and the relay driving transistor 13 is turned on. As a result, the exciting coil 3-2 of the main power switch means 3 is excited and the power switch 3-1 is turned on (see FIG. 2 (a)). Then, an excessively large rush current flows into the rectifier circuit 4 from the AC power source 1 through the rush current preventing resistor 2 and the power switch 3-1 (see FIG. 2 (d)). During a transient period during which the rush current flows, the main power supply smoothing capacitor 6 is gradually charged as shown in FIG. 2B, and the charging voltage rises, and the charging voltage of the smoothing capacitor 6 increases. Accordingly, when the stabilized DC voltage output from the stabilized DC power supply circuit 7 reaches a predetermined value (for example, 10 V), the exciting coil 5-2 of the short-circuit switch means 5 is necessary for driving the switch based on the voltage. The shorting switch 5-1 is turned on (see FIG. 2 (c)).

  The short-circuit switch means 5 for short-circuiting the rush current prevention resistor 2 is open (off) in the standby state, and in the standby state, a current flows through the rush current prevention resistor 2 and flows into the standby power supply circuit 30. Even after the switch 3-1 of the main power switch means 3 is turned on, the shorting switch 5-1 of the shorting switch means 5 remains off until the output voltage of the smoothing capacitor 6 reaches a certain value. As the main power switch 3-1 is turned on, a transient excessive current (that is, rush current) flowing into the main power circuit 20 is limited (suppressed) when passing through the rush current prevention resistor 2. The Since the short-circuit switch 5-1 short-circuits both ends of the rush current prevention resistor 2 only when the main power supply circuit 20 is started up and the stabilized DC voltage as the output voltage is in a normal operation state. During normal operation, no voltage drop or power loss due to the resistor 2 occurs.

  According to the first embodiment of the present invention, in a power supply apparatus having a main power supply circuit and a standby power supply circuit, the voltage of the AC power supply is rectified and smoothed by the rectification / smoothing circuit, and the DC power supply voltage for the main power supply and the standby DC In the circuit configuration for obtaining the power supply voltage, the main power supply circuit and the standby power supply circuit can share the rush current preventing resistor 2 for suppressing the rush current generated when the main power supply is turned on.

  As in the first embodiment of the present invention, the power supply configuration of an electric apparatus such as a television receiver is often a two-power supply configuration of the main power supply circuit 20 and the standby power supply circuit 30 of the microcomputer 11. In order to protect an excessive current flowing from the AC power supply 1 to the smoothing capacitor 6 of the rectifying / smoothing circuit when the power switch 3-1 of the main power switch means 3 is turned on, it is necessary to insert a rush current preventing resistor 2. Therefore, the resistor 2 requires a relatively large resistor. However, the rush current prevention resistor 2 interposed in series with such a power supply line causes a relatively large current to flow when the electric device normally operates. Therefore, the resistor 2 causes a voltage drop and a power loss in the power supply line. It will be. Therefore, a shorting switch 5-1 is connected in parallel to the rush current preventing resistor 2, and during normal operation, an exciting current is supplied to the relay coil 5-2 to turn on the relay switch 5-1. Since the current flows when the prevention resistor 2 is short-circuited and no current flows through the resistor 2, no voltage drop or power loss due to the resistor 2 occurs.

  Further, since the shorting switch 5-1 is also turned off when the main power switch 3-1 is open (off) as in the standby state, a current flows through the rush current prevention resistor 2, but in the standby state, the load (The main load is a microcomputer) and the current is small. Therefore, in the standby state, the voltage drop and power loss due to the rush current prevention resistor 2 are small, and it is not necessary to short the shorting switch 5-1.

  In the first embodiment of the present invention, the main power supply rush current prevention resistor and the standby rush current prevention resistor are combined as described above. Conventionally, the main power supply rectifier circuit and the standby rectification circuit are used. Since the circuit includes the rush current preventing resistors, the standby rush current preventing resistors are not required. The resistance value of the rush current preventing resistor 2 according to the first embodiment of the present invention may be set to a resistance value necessary for limiting (suppressing) the rush current when the main power is turned on.

  The present invention prevents a rush current of a power supply device in an electric device having a main power supply circuit and a standby power supply circuit, and protects a semiconductor component such as a full-wave rectifier diode used in a rectifier circuit for a main power supply. Useful.

The block diagram of the power supply device of the electric equipment of Example 1 of this invention. The timing chart explaining operation | movement of Example 1 of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... AC power supply 2 ... Rash current prevention resistor 3 ... Main power supply switch means 3-1 ... Main power supply switch 4 ... Main power supply rectifier circuit 5 ... Short circuit switch means 5-1 ... Short switch 6 ... Main power supply use Smoothing capacitor 7 ... Stabilized DC power supply circuit for main power supply 8 ... Standby rectifier circuit 9 ... Standby smoothing capacitor 10 ... Standby stabilized DC power supply circuit 11 ... Microcomputer 12 ... Operating means 13 ... Relay drive transistor 20 ... Main power supply Circuit 30 ... Standby power supply circuit Agent Patent attorney Susumu Ito

Claims (4)

A main power supply circuit that generates a DC power supply voltage for operating various electronic circuits in the electrical equipment, including a rectifier circuit that rectifies the voltage from the AC power supply and a smoothing capacitor that smoothes the rectified voltage;
A main power switch means disposed between the AC power supply and the main power supply circuit for turning on / off the supply of the AC power supply voltage from the AC power supply to the main power supply circuit;
A standby power supply circuit that inputs the voltage from the AC power supply from a branch point on a power supply line connecting the AC power supply and the main power supply switch means, and rectifies to generate a standby DC power supply voltage;
A rush current preventing resistor disposed on a power supply line between the AC power supply and the branch point and suppressing a rush current generated when the main power switch means is turned on;
Connected in parallel to the rush current prevention resistor, and after the main power supply switch means is turned on, turns on when the output voltage of the main power supply circuit reaches a predetermined value and shorts both ends of the rush current prevention resistor. And short-circuit switch means for turning off in a state where the predetermined value is not reached and opening both ends of the rush current prevention resistor;
A power supply device for electrical equipment, comprising: A control circuit capable of outputting a main power on / off signal based on a main power on / off command from the operating means, wherein a direct-current power voltage from the standby power circuit is supplied as an operating voltage;
Means for turning on / off the main power switch means based on a main power on / off signal from the control circuit;
The power supply device for an electric device according to claim 1, further comprising:   The main power switch means is composed of an electromagnetic relay having a relay switch and an exciting coil, and one end of the exciting coil is connected to a reference potential point via a collector / emitter path of the relay driving transistor, and the relay driving transistor The main power on / off signal from the control circuit is input to the base of the control circuit, and the other end of the exciting coil is connected to the DC power supply voltage output terminal of the standby power circuit. The power supply unit of the electrical equipment described. 4. The power supply device for an electric device according to claim 2, wherein the control circuit is constituted by a microcomputer.

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