JPH06205546A - Uninterruptible switching regulator - Google Patents

Abstract

PURPOSE:To make it possible to provide the use as an uninterruptible power source or a cordless power source by prolonging holding time characteristics from second unit to minute unit. CONSTITUTION:A charge circuit and a discharge circuit of an electrical double layer capacitor or a secondary battery 15 are installed to the tertiary side of a high-frequency transformer 4. The charge circuit has the electrical double layer capacitor or the secondary battery 15 connected to a tertiary winding N3. The discharge circuit has a tertiary side switching device 19 which is connected to the tertiary winding N3 and operates in synchronization with a primary side switching device 6 through a PWM switching control circuit 7. When an output voltage of a rectifier circuit 3 is more than a predetermined level, the charge circuit operates, and when the output voltage is less than the predetermined level, the discharge circuit operates.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switching type DC stabilized power supply with a high power factor and a small output ripple, an uninterruptible DC stabilized power supply for computer-related equipment requiring countermeasures against power failure, or a portable welding machine or an electric motor. The present invention relates to an uninterruptible switching regulator that is widely used for AC input cordless power supplies for tools and the like.

[0002]

2. Description of the Related Art FIG. 8 shows a schematic circuit diagram of a conventional switching regulator. A full-wave rectifier 3 for rectifying the AC power supply 1 via a high-frequency line filter 2 is provided on the primary side, and an input-side smoothing capacitor 3a, a primary winding N ₁ of a high-frequency transformer 4, a high-frequency semiconductor switching device are provided. A primary side circuit including an element such as an FET (Field Effect Transistor) 6 is configured. FET
The gate terminal of 6 is connected to the gate output terminal of a pulse width modulation (hereinafter referred to as PWM) switching control circuit 7. On the other hand, on the secondary side, 2
The secondary winding N ₂ , the high frequency rectification diode 8, the flywheel diode 9, the choke coil 10, and the output side smoothing capacitor 11 constitute a secondary side circuit.
The output voltage detection resistor 12 and the voltage dividing resistor 13 are connected to the output terminal of the secondary side circuit, and the load circuit of the load 14 is connected to the output terminal. The divided voltage between the output voltage detecting resistor 12 and the voltage dividing resistor 13 is connected to the output voltage input terminal of the PWM switching control circuit 7.

In this switching regulator, the alternating current supplied from the alternating-current power supply 1 is full-wave rectified by the full-wave rectifier 3 and smoothed by the input-side smoothing capacitor 3a to generate a DC voltage containing a ripple component as shown in FIG. Occur. This DC voltage is switched by the FET 6 to become a high frequency pulse voltage, which is transformed into a required voltage by the high frequency transformer 4. The transformed high frequency pulse voltage is smoothed by the high frequency rectifier diode 8, the flywheel diode 9, the choke coil 10 and the output side smoothing capacitor 11, and becomes a direct current as shown in FIG.

If the AC input voltage and load are constant, 1
The pulse width of the secondary side high frequency pulse voltage is constant, and a constant DC voltage V ₀ is always supplied to the load. However, since the output voltage V ₀ tends to change with the change of the AC input voltage or the load, the PWM switching control circuit 7 detects the voltage detected by the divided voltage between the output voltage detecting resistor 12 and the voltage dividing resistor 13. By modulating the pulse width of the pulse signal to the FET 6 according to the change ΔV, the pulse width of the primary side high frequency pulse voltage is controlled to make the output voltage V ₀ constant.

[0005]

However, in the conventional switching regulator described above, a DC voltage including a ripple component as shown in FIG. 9 is applied to both ends of the input smoothing capacitor 3a to charge the ripple portion. As a result of the current concentration, the AC input current has a non-linear waveform including many odd harmonics such as third, fifth, etc. as shown in FIG. For this reason, harmonic interference such as heat generation in the transformer of the substation in the input power distribution line or generation of abnormal sound has become a problem in recent years. This high frequency interference is now subject to legal regulation.

As shown in FIG. 10, a ripple component appears in the output voltage waveform depending on the capacity of the input side smoothing capacitor 3a. That is, a trapezoidal output waveform as shown by a broken line in a film capacitor or the like having a small capacity of the input-side smoothing capacitor 3a, and a ripple component becomes smaller as shown by a dashed line to a solid line as the capacity becomes larger like an electrolytic capacitor. go. Such an output voltage has no problem for a load in which the ripple component does not affect, but cannot be used for an IC circuit or the like.

Normally, in a switching power supply, it is required that the output voltage can be held for a certain time (10 to 20 msec) or more even if the AC power supply is instantly turned off, as a holding time characteristic. However, even if it has such a holding time characteristic in units of seconds, in the case of a power failure that occurs in units of minutes, the output voltage cannot be held, so a separate backup measure must be provided. It is an object of the present invention to solve the above-mentioned problems and to provide an uninterruptible switching regulator that can be used as an uninterruptible power supply or a cordless power supply by extending the holding time characteristic from seconds to minutes. To do.

[0008]

In order to achieve the above object, a first invention is a single forward type switching regulator, which does not include a smoothing capacitor for rectifying an alternating current from an alternating current power source, and the rectifying circuit. A primary side circuit in which a primary winding of a high frequency transformer and a primary side switching element are connected in series to the output side of the primary side switching element, and a primary side high frequency pulse voltage is generated by the primary side switching element;
A rectification and smoothing circuit is connected to the secondary winding of the high frequency transformer, and a secondary side circuit that supplies a DC output voltage to a load, and an electric double layer capacitor or a secondary battery and a choke in the tertiary winding of the high frequency transformer. Between the charging circuit in which a coil and a high-frequency rectifying diode are connected in series, and between the winding start end and the winding end end of the tertiary winding or a tap drawn from the middle of the winding, the electric double layer capacitor or Secondary battery and 3
A discharge circuit in which a secondary switching element is connected in series,
A pulse signal synchronized with the primary side switching element and the tertiary side switching element is output to perform a switching operation, and the pulse width of the pulse signal is modulated according to the fluctuation of the output voltage of the secondary side circuit in the previous period. And a pulse width modulation switching control circuit for controlling the pulse width of the primary side high frequency pulse voltage. If the output voltage of the rectifier circuit exceeds a predetermined level, the charging circuit operates, and if it falls below the predetermined level. The discharge circuit is operated.

A second invention is a flyback type switching regulator, which includes a rectifier circuit which does not include a smoothing capacitor for rectifying an alternating current from an alternating current power source, and a primary winding of a high frequency transformer on an output side of the rectifier circuit. The primary side switching element is connected in series, and the primary side circuit that generates the primary side high frequency pulse voltage by the primary side switching element and the primary winding of the high frequency transformer is wound in the opposite polarity. The secondary winding is connected to a rectification / smoothing circuit to supply a DC output voltage to the load, and the tertiary winding wound in the opposite polarity to the primary winding of the high frequency transformer is electrically connected. A charging circuit in which a double-layer capacitor or a secondary battery and a high-frequency rectifier diode are connected in series, and between a winding start end of the tertiary winding or a tap drawn from the middle of the winding and a winding end, The electricity A discharge circuit in which a multilayer capacitor or a secondary battery, a choke coil, and a tertiary side switching element are connected in series, and a pulse signal synchronized with the primary side switching element and the tertiary side switching element are output to perform a switching operation. And a pulse width modulation switching control circuit that controls the pulse width of the primary side high frequency pulse voltage by modulating the pulse width of the pulse signal according to the fluctuation of the output voltage of the secondary side circuit, When the output voltage of the circuit exceeds a predetermined level, the charging circuit operates, and when the output voltage falls below the predetermined level, the discharging circuit operates.

Further, a third invention is a full-bridge type switching regulator, which does not include a smoothing capacitor for rectifying an alternating current from an alternating current power source, and a primary winding of a high frequency transformer on an output side of the rectifying circuit. And four bridge-connected primary side switching elements are connected in series, and positive / negative alternating is performed by the primary side switching elements 1
A primary side circuit for generating a secondary side high frequency pulse voltage and a rectification / smoothing circuit connected to the secondary winding of the high frequency transformer,
A secondary side circuit for supplying a DC output voltage to a load and an electric double layer capacitor or a secondary battery and four high frequency rectifying diodes bridge-connected to a choke coil are connected in series to the tertiary winding of the high frequency transformer. Charging circuit, the winding start end of the tertiary winding and the electric double layer capacitor or 2
A third side first switching element is connected between the positive electrode of the secondary battery and the winding end of the tertiary winding or the first tap pulled out from the middle of the winding and the electric double layer capacitor or A third side fourth switching element that operates in synchronization with the third side first switching element is connected in series between the negative electrode of the secondary battery and the winding end end of the third winding. A secondary side second switching element is connected between the electric double layer capacitor or the positive pole of the secondary battery, and a second tap drawn from the winding start end of the tertiary winding or the middle of the winding. A discharge circuit in which a tertiary side third switching element that operates in synchronization with the tertiary side second switching element is connected in series between the electric double layer capacitor or the negative electrode of the secondary battery, and the primary circuit. Bridge-connected to each other And two switching elements that face, said tertiary first, fourth switching element or tertiary second, with causing the output to the switching operation of the pulse signal synchronized with a third switching element, the two
A pulse width modulation switching control circuit for controlling the pulse width of the primary side high frequency pulse voltage by modulating the pulse width of the pulse signal according to the fluctuation of the output voltage of the secondary side circuit,
When the output voltage of the rectifying circuit exceeds a predetermined level, the charging circuit operates, and when the output voltage falls below the predetermined level, the discharging circuit operates. In the switching regulator according to each of the above inventions, the rectifying circuit may include a smoothing capacitor.

[0011]

According to the switching regulator of the present invention, the alternating current input to the primary side from the alternating current power source is rectified by the rectifying circuit into a full-wave sine wave and then switched by the primary side switching element. The high frequency pulse voltage generated by the switching induces a voltage in the secondary winding and the tertiary winding. The voltage induced in the secondary winding passes through a rectifying and smoothing circuit to become a smooth DC output voltage and is supplied to the load.

While the input AC voltage, that is, the output voltage of the rectifying circuit, exceeds a predetermined level, a voltage is induced in the tertiary winding to operate the charging circuit and charge the electric double layer capacitor or the secondary battery. Also, while the output voltage of the rectifier circuit is lower than a predetermined level, or when the AC power supply is cut off due to a power failure or the like, the charging voltage of the electric double layer capacitor or the secondary battery is higher than the voltage induced in the tertiary winding. Wins and the discharge circuit operates. The charging voltage of the electric double layer capacitor or the secondary battery is switched by the switching element on the tertiary side to become the tertiary high frequency pulse current, and the voltage is induced in the secondary winding by this tertiary high frequency pulse current, and the direct current is applied to the load. Output voltage is supplied. Therefore, even if the input AC voltage becomes lower than a predetermined level, a constant DC output voltage that does not drop or is intermittent is obtained at the load end of the secondary side circuit.

[0013]

Embodiments of the present invention will now be described with reference to the drawings. (1) First Embodiment FIG. 1 is a schematic circuit diagram showing a single forward type switching regulator. In this circuit, a high-frequency rectifier diode 5 is added to the primary side of the conventional switching regulator shown in FIG.
Since a has the same configuration as the conventional circuit except that a is removed and a third side circuit is newly provided, the same reference numerals are given to the portions corresponding to the conventional circuit. The tertiary circuit is composed of a charging circuit and a discharging circuit for the electric double layer capacitor 15. A secondary battery may be used instead of the electric double layer capacitor 15.

The charging circuit comprises a tertiary winding N ₃ , an electric double layer capacitor 15, a choke coil 16, a high frequency rectifying diode 17 and a flywheel diode 18. The tertiary winding N ₃ is wound with the same polarity as the primary winding N ₁ . The positive pole of the electric double layer capacitor 15 is connected to the winding start end of the tertiary winding N ₃ , and the negative pole is connected through the smoothing choke 16 and the high frequency rectifier diode 17 to the tertiary winding N 3.
It is connected to the end of winding ₃ . The flywheel diode 18 includes a choke coil 16 and a high frequency diode 1.
It is provided between the midpoint of the anode 7 and the winding start end of the tertiary winding N ₃ . The electric double layer capacitor 15
Is the capacitance in farads, which is 10 ³ of the electrolytic capacitor.
It has a capacity of about 10 ⁶ times. Two electric double layer capacitors 15 are connected in series in consideration of practicality, but the present invention is not limited to this, and a single unit or three or more units may be connected.

The discharge circuit comprises the tertiary winding N _{3, the} electric double layer capacitor 15, the tertiary FET 19 and the reverse current blocking diode 20. The drain terminal of the tertiary FET 19 is connected via the backflow blocking diode 20 to the winding end of the tertiary winding N ₃ or to the tap T pulled out from the middle of the winding, and the source terminal thereof is the electric double layer capacitor 15 Of the primary side FET 6 and the output terminal D of the PWM switching control circuit 7 together with the gate terminal of the primary side FET 6. This makes 3
The secondary side FET 19 performs high frequency switching operation in synchronization with the primary side FET 6. The reverse current blocking diode 20 may be omitted.

The operation of the switching regulator having the above configuration will be described below. The sinusoidal alternating current supplied from the AC power supply 1 is rectified by the full-wave rectifier 3 through the high-frequency line filter 2 into a full-wave sinusoidal pulsating waveform shown in A in FIG. 2 and supplied to the primary side of the high-frequency transformer 4. To be done. The full-wave sinusoidal pulsating current is passed through the primary winding N ₁ and the reverse current blocking diode 5 to the primary side FET 6. Since a high frequency switching pulse signal is applied from the PWM switching control circuit 7 to the gate terminal of the FET 6, the full-wave sinusoidal voltage is directly switched (chopped) by the FET 6 and output to the secondary side. Direct chopping of the full-wave rectified voltage with a large amount of pulsating current is called direct high frequency chopping.

The high frequency pulse voltage on the primary side which is switched by the primary side FET 6 is transformed by the high frequency transformer 4 and output to the secondary side. The high-frequency pulse voltage on the secondary side is converted into a direct current again by the high-frequency rectifier diode 8, smoothed by the flywheel diode 9, the choke coil 10 and the output-side smoothing capacitor 11, and the direct-current output voltage V ₀ is supplied to the load 14. It Here, when the AC input voltage or the load fluctuates and the output voltage V ₀ changes, the PWM switching control circuit 7 compares the output voltage detected by the resistors 12 and 13 with the internal reference voltage, and changes the output voltage. The pulse width of the pulse signal to the gate terminal of the FET 6 is modulated in accordance with. This gives 1
The pulse width of the secondary high-frequency pulse voltage changes and the output voltage is maintained at a constant V ₀ . In such constant voltage control or constant current / constant power control, the primary side voltage corresponding to the secondary side output voltage level V ₀ for which the PWM switching control circuit 7 can control the pulse width of the primary side high frequency pulse voltage. The level is hereinafter referred to as a slice level.

If there is no tertiary circuit, as described above, a trapezoidal wave-shaped hum ripple that is synchronized with the DC input voltage (50 Hz or 60 Hz) of the commercial AC power source 1 shown in FIG. 2B appears. , Will hinder the load. In order to eliminate this hum ripple, the smoothing capacitor 11 becomes extremely large and the holding time characteristic of the output voltage cannot be obtained. In this embodiment, since the tertiary circuit including the charging circuit and the discharging circuit of the electric double layer capacitor 15 is provided, the hum ripple is eliminated, and the function as an uninterruptible power supply that can obtain the holding characteristic for a long time is obtained. Have.

The operation of this tertiary circuit will be described below.
In the section P in which the level of the pulsating current voltage of the DC output of the rectifier 3 exceeds the slice level S as indicated by A in FIG.
As shown in FIG. 3, the voltage E ₁ is induced in the tertiary side circuit by the current I ₁ flowing in the primary side circuit when the secondary side FET 6 is ON, and the voltage E ₁ is induced in the tertiary winding N ₃ in FIG. The current I ₃ flows in the direction indicated by the solid arrow. This current I ₃ is smoothed by the choke coil 16 and the current I ₄ charges the electric double layer capacitor 15. When the primary side FET 6 is on, the tertiary side FET 19 is also on in synchronization with this, but the voltage E ₁ induced by the current I ₁ is the charging voltage E ₄ of the electric double layer capacitor 15. Since the electric double layer capacitor 15 is higher and the electric double layer capacitor 15 is being charged, the drain current is in a state of being extremely small and not flowing. Therefore,
The tertiary FET 19 at this time is, so to speak, merely performing an idle operation. In this section P, while the tertiary circuit charges the electric double layer capacitor 15 as described above, in the primary circuit, the output voltage of the rectifier 3 causes the secondary side on the secondary side, as shown by C in FIG. To the output voltage V ₀ .

Next, when the level of the pulsating current voltage of the DC output of the rectifier 3 becomes a section Q lower than the slice level S as shown by A in FIG. 2, or when the DC output of the rectifier 3 cannot be obtained due to a power failure, The charging voltage E ₄ of the electric double layer capacitor 15 becomes relatively higher than the induced voltage E ₁ of the tertiary winding N ₃ . Therefore, the currents I ₃ and I ₄ flowing in the charging circuit at the time of charging are stopped, and the number of turns N ₃ from the winding start end of the tertiary winding N ₃ to the halfway tap T from the discharging circuit, that is, the electric double layer capacitor 15. The discharge current I ₅ flows through the reverse current blocking diode 20 and the tertiary side FET 19 via the part '. As a result, the FE on the tertiary side that was idle during charging
T19 switches to the main operation and performs high frequency switching operation. Since the discharge current I ₅ flows through the winding N ₃ ′, a voltage is induced in the secondary winding N ₂ on the secondary side, and the load 14
An output current I ₇ flows through the output current I ₇ , and an output voltage V ₀ is supplied as indicated by D in FIG. In this way, the output voltage V ₀ is supplied to the secondary side by the output voltage of the rectifier 3 in the section P and by the charging voltage of the electric double layer capacitor 15 in the section Q, and as a result, indicated by E in FIG. Thus, the constant output voltage V ₀ is supplied throughout the entire section.

This operation will be described in more detail using an approximate relational expression. If the voltage across the load 14 is V ₀ , the following relational expression holds between V ₀ and E ₄ .

## EQU1 ## V ₀ = E ₄ (N ₂ / N ₃ ) Further, E ₄ and the voltage E ₁ induced by the switching operation of the primary side FET 6 satisfy the following relational expression.

[ _Equation 2] E ₄ = E ₁ (T _ON1 / T) where T _ON1 / T is the primary side FET as shown in FIG.
6 is a duty ratio with respect to the cycle T of the switching ON time of 6, and its value is determined so that T _ON1 becomes the center point of the control range of constant voltage, constant current, or constant power control.

For convenience of explanation, it is assumed that there is no voltage drop across the reverse current blocking diode 20 and the tertiary FET 19.
Assuming that the duty ratio of the secondary side FET 19 is T _ON1 / T as in the primary side FET 6, the electric double layer capacitor 1
Since the voltage E ₄ charged to 5 becomes the input voltage for obtaining V ₀ ′, the voltage V ₀ ′ across the load 14 is expressed by Equation 3. Note that, here, it is assumed that there is no intermediate tap T in the tertiary winding N ₃ and the backflow prevention diode 20 is connected from the winding end end in the description procedure.

Equation 3] _{V 0 '= E 4 (T} ON1 / T) (N 2 / N 3) Therefore, V _0' is T _ON1 / T becomes a duty ratio amount corresponding V ₀
It will be a lower value and the output will drop.

[0023] Therefore, in order to correct this, the following formula between pull the tap T from the middle of the third winding N _3, 'The provision of portions of, N _3' turns N ₃ and N ₃ Is established.

## EQU4 ## N ₃ ′ = N ₃ (T _ON1 / T) When N ₃ in Expression 3 is changed to N ₃ ′, V ₀ ′ is represented by the following expression.

V ₀ ′ = E ₄ (T _ON1 / T) [N ₂ / (N ₃ T _ON1 / T)] = E ₄ (N ₂ / N ₃ ) = V ₀ Therefore, V ₀ ′ is V ₀ Therefore, the output of the load does not change. As a result, the output voltage does not drop.

As described above, in this embodiment, the electric double layer capacitor 15 functions as a smoothing capacitor normally connected to the output side of the rectifier 3 and has a large capacity. Has retention time characteristics. Therefore,
The output voltage can be sufficiently held against an instantaneous blackout of less than 3 minutes that may occur in the normal power system. A computer-related device has a longer life than a backup battery, does not require consideration of overcharging and overdischarging, and is a safe power supply device. Also, because it has such a long holding time characteristic, this switching regulator can be used as a power supply device for portable welding machines and electric tools that are not used frequently and continuously, and can be rapidly charged during charging and can be discharged. It is possible to take advantage of the fact that it can be used for a long time. That is, these main bodies can be attached to and detached from the power supply device, can be connected to the power supply device when not in use, can be detached from the power supply device when used, and can be operated in a cordless state.

(2) Second Embodiment FIG. 5 is a schematic circuit diagram showing a flyback type switching regulator used as a small-capacity power supply device. In the figure, the PWM switching control circuit is omitted for simplification, and the FETs 6 and 19 are switch-displayed. The main difference from the first embodiment is that the secondary winding N ₂ forming the secondary side circuit and the tertiary winding N ₃ forming the tertiary side circuit.
Is wound in the opposite polarity to the primary winding N ₁ . The choke coil and the flywheel diode are not provided in the secondary circuit, and the choke coil and the flywheel diode are not provided in the charging circuit of the electric double layer capacitor 15 of the tertiary circuit. Instead, a choke coil 21 is provided between the reverse current blocking diode 20 and the FET 19 of the discharge circuit. Further, the midpoint between the choke coil 21 and the FET 19 is connected to the positive pole of the electric double layer capacitor 15 via the flywheel diode 22, and the midpoint between the choke coil 21 and the reverse current blocking diode is the diode for the return circuit. It is connected via 23 to the negative pole of the electric double layer capacitor. The reverse current blocking diode 20 can be omitted.

The operation of this flyback type switching regulator will be described below. In the section P where the output voltage of the rectifier 3 exceeds the slice level S, the primary side F
When ET6 is ON, magnetic energy is stored in the iron core of the high frequency transformer 4 by the exciting current I ₁ flowing through the primary winding N ₁ . When the primary side FET 6 is OFF, the magnetic energy stored in the iron core is supplied as reversal energy to the secondary side and the tertiary side. A voltage is induced in the secondary winding N ₂ by the inversion energy supplied to the secondary side, and the voltage is applied to the load 14 via the high frequency rectifier diode 8 and the smoothing capacitor 11.
Is output to. Here, the current I ₆ flows through the secondary side circuit. On the other hand, due to the reversal energy supplied to the tertiary side, 3
A voltage is induced in the next winding N ₃ , and the electric double layer capacitor 15 is charged by the voltage. Here, the charging current of I ₄ flows through the charging circuit via the high frequency rectifier diode 17. A tertiary FET that operates in synchronization with the primary FET 6.
19 performs an idle operation as in the above-mentioned embodiment.

When the output voltage of the rectifier 3 is in the section Q lower than the slice level S, or when the AC power source is cut off due to a power failure or the like, the voltage stored in the electric double layer capacitor 15 causes the current I ₅ to turn into the tertiary winding. It flows through the backflow blocking diode 20 and the choke coil 21 through the tap T of N ₃ , and is switched by the tertiary FET 19. As a result, a voltage is induced in the secondary winding N ₂ , a current I ₇ flows in the secondary side circuit, and the output voltage is supplied to the load 14. This output voltage is, as described in the first embodiment, a section P in which the output voltage of the rectifier 3 exceeds the slice level.
Is the same as the output voltage of. Therefore, the voltage supplied to the load 14 does not drop, and is maintained at a constant voltage for a long time even if the power is cut off due to a power failure or the like.

The characteristic in this section Q is that the choke coil 21 of the discharge circuit plays a role equivalent to the inductance of the choke input type smoothing circuit of the rectification circuit on the secondary winding N ₂ side, and the output side smoothing capacitor 11 This is to prevent an excessive current from flowing into the device, and at the same time, alleviate the burden of the inrush current of the tertiary side FET 19. Another feature is that the tertiary side FET 19 performs a single forward type switching operation when the discharge circuit is operating. Furthermore, another feature is that the third side FET 19 is OF
In the case of F, the inversion energy of the choke coil 21 is returned to the electric double layer capacitor 15 via the flywheel diode 22 and is returned to the choke coil 21 via the diode 23.

(3) Third Embodiment FIG. 6 is a schematic circuit diagram of a bridge type switching regulator normally used in a large capacity power supply device. In the figure, for simplification, as in the second embodiment, the FE
T6a to 6d and 19a to 19d are switch-displayed, and the pulse width modulation switching control circuit is omitted. In this bridge type switching regulator, four FETs 6a to 6d are bridge-connected to the primary side circuit, and backflow prevention diodes 5a and 5b are connected in series to the adjacent first FET 6a and second FET 6b, respectively. One opposing first FET 6a and fourth FET 6d operate in synchronization, and the other opposing second FET 6b and third FET 6d
6c operates synchronously, but the first FET 6a and the fourth F
It operates in a phase opposite to that of ET6d.

The winding start end and winding end of the secondary winding N ₂ of the secondary side circuit are connected to the anodes of the high frequency rectifier diodes 8a and 8b, respectively, and the cathodes of the high frequency diodes 8a and 8b are connected to each other at a point P. Has been done. Then, between this connection point P and the midway tap T of the secondary winding,
Similar to the first embodiment, a rectifying / smoothing circuit is formed. Note that the four high-frequency rectifier diodes may be bridge-connected like the primary side without providing the intermediate tap T.

The charging circuit of the tertiary side circuit comprises an electric double layer capacitor 15 and four high frequency rectifying diodes 17a to 17d bridged with the choke coil 16. The midpoint of the first high-frequency rectifier diode 17a and the third high-frequency rectifier diode 17c is connected to the winding start end of the tertiary winding N ₃ , and the second high-frequency rectifier diode 17b and the fourth high-frequency rectifier diode 17b are connected.
The middle point of the high frequency rectifier diode 17d is connected to the winding end of the tertiary winding N ₃ . The cathodes of the first and second high frequency rectifier diodes 17a and 17b are connected to the positive pole of the electric double layer capacitor 15, and the electric double layer capacitor 1
The negative pole of No. 5 is connected to the anodes of the third and fourth high frequency rectifier diodes 17c and 17d via the choke coil 16.

The discharge circuit of the tertiary side circuit includes the electric double layer capacitor 15 and two reverse current element diodes 20.
a and 20b and four tertiary FETs 19a to 19d. Positive pole of the electric double layer capacitor 15 is connected to the winding start end of the tertiary winding N ₃ via the first 1FET19a, connected to the winding end of the tertiary winding N ₃ via the first 2FET19b There is. The negative pole of the electric double layer capacitor 15 is connected to the midway tap T ₁ near the winding end of the third winding N ₃ via the fourth FET 19d and the first reverse current blocking diode 20a, and
It is connected to a midway tap T ₂ near the winding start end of the third winding N ₃ via the third FET 19c and the second reverse current blocking diode 20b. The third side first and fourth FETs 19a, 1
9d operates in synchronism with the first and fourth FETs 6a and 6d of the primary side circuit, and the third and second FETs 19b and 19d.
c is synchronized with the second and third FETs 6b and 6c of the primary side circuit and operates in a phase opposite to that of the third side first and fourth FETs 19a and 19d. The first and second backflow prevention diodes 20a and 20b can be omitted.

The operation of this bridge type switching regulator will be described below. In the section P in which the output voltage of the rectifier 3 exceeds the slice level S, when the first and fourth FETs 6a and 6d of the primary side circuit are turned on, the primary winding N ₁
The current in the positive direction of I ₁ flows through. Next, the first and fourth FETs 6a and 6d of the primary side circuit are turned off and the second and third FEs are turned on.
T6b, 6c is turned ON, a negative current flows I ₁ 'to the primary winding. In this way, positive and negative currents I ₁ and I ₁ ′ alternately flow through the primary winding N ₁ . The primary winding N positive current I ₁ to ₁
Flows, a voltage is induced between the winding start end of the secondary winding N ₂ and the midway tap T, and at the same time, a voltage is induced in the tertiary winding N ₃ . Due to the voltage induced in the secondary winding N ₂ , a current I ₆ flows in the secondary side circuit and the output voltage is supplied to the load 14. Due to the voltage induced in the tertiary winding N ₃ , the charging current of I ₄ is supplied to the electric double layer capacitor 15 by the choke coil 16 and the first and fourth high frequency rectifying diodes 17a, 17.
The electric double layer capacitor 15 is charged by flowing through d.

When a negative current I ₁ ′ flows through the primary winding, a reverse voltage is induced between the midway tap T of the secondary winding N _{2 and} the end of the winding, and at the same time, the tertiary winding N _{3 ′.} Also, a reverse voltage is induced. Due to the reverse voltage induced in the secondary winding N ₂ , a current I ₆ ′ flows in the secondary side circuit and the output voltage is supplied to the load. Due to the voltage induced in the tertiary winding N ₃ , the charging current of I ₄ ′ is applied to the electric double layer capacitor 15 by the choke coil 16 and the second and third high frequency rectifier diodes 17b, 17.
The electric double layer capacitor 15 is charged by flowing through c. In addition, in this section P, the tertiary side first to fourth floors
The ETs 19a to 19d are idling similarly to the first embodiment.

When the output voltage of the rectifier is in the section Q lower than the slice level S or when the AC power source is cut off due to a power failure or the like, the third side first to fourth FETs 19a to 19d are switched from the idle operation to the main operation. That is, this first,
The 4FET19a, 19d by an electric double layer winding of third winding N ₃ from the capacitor 15 start end and a first reverse-blocking diode 20a through a portion between the first middle tap T ₁
A positive current, I _5, flowing through is switched. Further, by the second and third FETs 19b and 19c which operate in the opposite phase to the first and fourth FETs 19a and 19d, the electric double layer capacitor 15 ends the winding end of the tertiary winding N ₃ and the second halfway tap T _2. The negative current I ₅ ′ flowing through the second reverse current blocking diode 20b through the portion between is switched.

[0036] Thus, the third winding N ₃ positive and negative current I ₅ in, I ₅ 'flows result, I ₇ is a voltage in the secondary winding N ₂ is induced in the secondary circuit, I _7' Current flows and the output voltage is supplied to the load 14. As described in the first embodiment, the output voltage of the rectifier 3 is the slice level S.
It is the same as the output voltage of the section P that exceeds the range. Therefore, the voltage supplied to the load 14 does not drop, and is maintained at a constant voltage for a long time even if the power is cut off due to a power failure or the like.

(4) Other Embodiments In each of the above embodiments, each switching regulator operates effectively even if the rectifier 3 includes an input side smoothing capacitor. In this case, the output of the input side smoothing capacitor is
The waveform is not a full-wave sine waveform as indicated by A in FIG. 2, but a smooth waveform including some ripples as shown in FIG. Therefore, during normal operation, there is no section where the level is lower than the slice level S, and the output voltage is not supplied from the electric duograph capacitor 15 of the tertiary side circuit to the secondary side. However, when the AC input voltage fluctuates significantly or the AC input voltage is cut off due to a power failure or the like, and the output voltage of the rectifier 3 falls below the slice level S, the electric double layer capacitor 15 of the tertiary side circuit outputs 2 The output voltage is supplied to the secondary side.

[0038]

As is apparent from the above description, the present invention has the following effects. While the input AC voltage, that is, the output voltage of the rectifier circuit exceeds a predetermined level, the DC output voltage is supplied to the load by the output voltage of the rectifier circuit, and when it becomes lower than the predetermined level, a large capacity of farad unit of the tertiary circuit Since the DC output voltage is supplied to the load by the charging voltage of the electric double layer capacitor or the secondary battery, a constant DC output voltage with no drop is obtained even if the input AC voltage drops, and the holding time characteristic is in seconds. To be expanded to the minute. Therefore, a constant output voltage can be supplied even if the AC power supply is cut off in minutes due to a power failure or the like, and it is not necessary to provide a power failure countermeasure such as a backup battery in computer-related equipment. It can also be used as a cordless power source for portable welding machines and electric tools.

[Brief description of drawings]

FIG. 1 is a schematic circuit diagram of a single-forward type switching regulator according to a first embodiment of the present invention.

FIG. 2A is a waveform diagram of the output voltage of the rectifier, B is a waveform diagram of the output voltage of the load end when there is no tertiary circuit, and C is a load end supplied by the output voltage of the rectifier in the P section of A. Waveform diagram of the output voltage of D, D is a waveform diagram of the output voltage of the load end supplied by the charging voltage of the electric double layer capacitor of the tertiary circuit in the Q section of A, E is the output of the load end over the entire section of A It is a wave form diagram of a voltage.

3 is an enlarged circuit diagram of the tertiary circuit of FIG.

FIG. 4 is a switching pulse waveform diagram of an FET.

FIG. 5 is a schematic circuit diagram of a flyback type switching regulator according to a second embodiment of the present invention.

FIG. 6 is a schematic circuit diagram of a bridge type switching regulator according to a third embodiment of the present invention.

FIG. 7 is a diagram showing an output voltage waveform and a slice level of a smoothing capacitor when a smoothing capacitor is provided on the primary side.

FIG. 8 is a schematic circuit diagram of a conventional switching regulator.

9 is a waveform diagram of the output voltage and the input current of the smoothing capacitor on the primary side in the conventional circuit of FIG.

10 is a waveform diagram of an output voltage in the conventional circuit of FIG.

[Explanation of symbols]

1 ... AC power supply, 2 ... High frequency line filter, 3 ... Full wave rectifier, 4 ... High frequency transformer, 5 ... High frequency rectifier diode, 6
... primary side switching element, 7 ... PWM switching control circuit, 8 ... high frequency rectifying diode, 9 ... flywheel diode, 10 ... choke coil, 11 ... output side smoothing capacitor, 14 ... load, 15 ... electric double layer capacitor, 16 ... choke coil, 17 ... high-frequency rectifier diode, 18 ... fly-fly field diode, 19 ... tertiary side switching element, 21 ...
Choke coil, N ₁ ... primary winding,
N ₂ ... ₂ windings, N ₃ ... ₃ winding.

Claims (4)

[Claims] 1. A rectifier circuit which does not include a smoothing capacitor for rectifying an alternating current from an alternating current power source, a primary winding of a high frequency transformer and a primary side switching element are connected in series to the output side of the rectifier circuit, A secondary circuit for supplying a DC output voltage to a load by connecting a primary side circuit for generating a primary side high frequency pulse voltage by a primary side switching element and a rectification / smoothing circuit to the secondary winding of the high frequency transformer. A charging circuit in which an electric double layer capacitor or a secondary battery, a choke coil, and a high-frequency rectifier diode are connected in series to the tertiary winding of the high-frequency transformer; and a winding start end and a winding end end of the tertiary winding, or A discharge circuit in which the electric double layer capacitor or the secondary battery and a tertiary side switching element are connected in series between the tap drawn out from the middle of the winding, and the primary side switch Outputs a pulse signal synchronized with the switching element and the switching element on the tertiary side to perform the switching operation, and modulates the pulse width of the pulse signal according to the fluctuation of the output voltage of the secondary side circuit in the previous period to increase the primary side high frequency. A pulse width modulation switching control circuit for controlling the pulse width of the pulse voltage, wherein the charging circuit operates when the output voltage of the rectifying circuit exceeds a predetermined level, and the discharging circuit operates when the output voltage falls below the predetermined level. An uninterruptible switching regulator characterized in that 2. A rectifier circuit which does not include a smoothing capacitor for rectifying an alternating current from an alternating current power source, and a primary winding of a high frequency transformer and a primary side switching element are connected in series to the output side of the rectifier circuit, A primary side circuit for generating a primary side high frequency pulse voltage by a secondary side switching element, and a secondary circuit wound in a polarity opposite to that of the primary winding of the high frequency transformer.
A secondary side circuit that connects a rectification and smoothing circuit to the secondary winding and supplies a DC output voltage to the load, and a secondary winding that has a polarity opposite to that of the primary winding of the high frequency transformer.
A charging circuit in which an electric double layer capacitor or a secondary battery and a high-frequency rectifier diode are connected in series to a secondary winding, a winding start end of the tertiary winding or a tap and a winding end drawn from the middle of the winding. A discharge circuit in which the electric double layer capacitor or the secondary battery, a choke coil, and a tertiary switching element are connected in series between the end and a pulse synchronized with the primary switching element and the tertiary switching element. A pulse width modulation that outputs a signal to perform a switching operation and modulates the pulse width of the pulse signal in accordance with the fluctuation of the output voltage of the secondary side circuit to control the pulse width of the primary side high frequency pulse voltage. A switching control circuit, wherein the charging circuit operates when the output voltage of the rectifier circuit exceeds a predetermined level, and the discharge frequency when the output voltage falls below the predetermined level. Uninterruptible of the switching regulator, characterized in that but has to work. 3. A rectifier circuit that does not include a smoothing capacitor that rectifies alternating current from an alternating current power source, and four primary side switching elements bridge-connected to the primary winding of a high frequency transformer on the output side of the rectifier circuit. Are connected in series, and a primary side circuit that generates a positive side high frequency pulse voltage alternating with the primary side switching element, and a rectification and smoothing circuit are connected to the secondary winding of the high frequency transformer to connect to a load. A secondary side circuit for supplying a DC output voltage, and an electric double layer capacitor or a secondary battery and a choke coil are bridge-connected to the tertiary winding of the high frequency transformer.
A charging circuit in which a plurality of high-frequency rectifier diodes are connected in series, and a tertiary-side first switching element are provided between the winding start end of the tertiary winding and the positive pole of the electric double layer capacitor or the secondary battery. The third tap is connected between the end of the tertiary winding or the first tap drawn out from the middle of the winding and the negative electrode of the electric double layer capacitor or the secondary battery.
While the tertiary side fourth switching element that operates in synchronization with the secondary side first switching element is connected in series, the winding end end of the third winding and the electric double layer capacitor or the positive electrode of the secondary battery are connected. A secondary side second switching element is connected in between, and a second tap drawn from the winding start end of the tertiary winding or the middle of the winding and the electric double layer capacitor or the negative electrode of the secondary battery. A discharge circuit in which a tertiary side third switching element that operates in synchronization with the tertiary side second switching element is connected in series, and two switching elements that are bridge-connected to the primary side and face each other. And a pulse signal synchronized with the tertiary-side first and fourth switching elements or the tertiary-side second and third switching elements to perform a switching operation and to output the secondary-side circuit. A pulse width modulation switching control circuit that modulates the pulse width of the pulse signal according to voltage fluctuations to control the pulse width of the primary side high frequency pulse voltage, and the output voltage of the rectifier circuit exceeds a predetermined level. An uninterruptible switching regulator, wherein the charging circuit operates, and the discharging circuit operates when the voltage drops below the predetermined level. 4. The uninterruptible switching regulator according to claim 1, wherein the rectifier circuit includes a smoothing capacitor.