JP2570085Y2 - Power circuit - Google Patents

Description

[Detailed description of the invention]

[0001]

This invention is to reduce the size of a low-noise, high-efficiency resonant power supply useful for audio equipment and the like by partially converting it to a hybrid integrated circuit (HIC), and to provide a large-capacity, high-voltage capacitor and integrated circuit. The present invention relates to a power supply circuit that has increased versatility by externally providing an inductance that is not suitable for realization.

[0002]

2. Description of the Related Art In the field of audio equipment and the like, which are becoming more multifunctional and miniaturized, if a power supply circuit is constituted by discrete components, the appearance of the apparatus becomes large. Therefore, recently, a miniaturized circuit using a hybrid integrated circuit (HIC) has been used. It tends to be. HIC
As is well known, an active element such as a transistor or a diode, or a passive element such as a resistor or a capacitor, or a combination of an IC or an LSI on a substrate made of a thin film or a thick film, is a discrete circuit. It can be made much smaller in size and has high reliability in terms of earthquake resistance.

[0003]

However, since the resonance power supply performs a series resonance or a parallel resonance, a capacitor or an inductance is indispensable in its configuration, and a capacitor is not less than a capacitor in other circuit parts other than the resonance circuit. It is inevitable to use parts that are difficult to integrate such as. The idea is that in the above-mentioned resonance type power supply circuit, most of the circuit parts are reduced to HIC by using external capacitors and inductances that are not suitable for integration, and the constants of external components are arbitrarily set. The purpose is to increase versatility by making it selectable.

[0004]

In order to achieve the above object, according to the present invention, a series resonance circuit and a parallel resonance circuit are provided.
A switching unit having a switching element that switches a current flowing through these resonance circuits, and a timing control unit that controls operation timing of the switching element,
In a resonance type power supply circuit which causes a series resonance with respect to a current during an on period of the switching element and a parallel resonance with respect to a voltage during an off period of the switching element, the series resonance circuit and the parallel resonance The present invention is characterized in that a resonance capacitor and an inductance of a circuit and a switching frequency setting capacitor of the timing control section are externally provided, and the remaining portion is configured as a hybrid integrated circuit.

[0005]

[Function] A resonance type power supply that achieves high efficiency and low noise by using current resonance and voltage resonance requires series and parallel resonance circuits and a switching circuit, and these circuits include capacitors and inductances. Use In this invention, a switching frequency setting capacitor with a low withstand voltage but a large capacitance, a parallel resonance capacitor with a small capacitance but a large withstand voltage, a series resonance capacitor that is indispensable in the circuit configuration, and a resonance that is not suitable for integration. By making the inductance for feedback and feedback external, and making the partial circuit composed of other semiconductor elements and resistors into HIC,
The size of the entire power supply circuit is reduced by the HIC, and a general-purpose power supply is realized by arbitrarily setting external component constants.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a main part circuit diagram of a power supply circuit according to an embodiment of the present invention. The entire power supply circuit shown in this embodiment is of a switching inverter type utilizing voltage resonance and current resonance, and has been filed by the present applicant as Japanese Patent Application No. 3-166383. First, the principle configuration of the power supply device will be described with reference to FIG. In this figure, 1 is a DC power supply, 2 is a main switching element that can be turned on and off at an arbitrary timing, and a switching means for switching the DC power supply 1 to convert it into AC, and 3 is a full-wave AC input supplied. DC output means for rectifying and smoothing with a capacitor to obtain a DC output, 4 is a series resonance circuit formed in series with a current flowing through the output terminal of the switching means 2, and 5 is a voltage generated at the output terminal of the switching means 2. A parallel resonance means formed in parallel with the switching means 2;
Is a timing control means having a drive element for turning on the switching element intermittently.

FIG. 3 is a block diagram showing the basic principle of the circuit shown in FIG. The general operation will be described with reference to FIG. The main switching elements S1 and S2 are alternately turned on at regular intervals under the control of the timing control means 6,
The turning off is repeated, but has a period in which the turning off is performed at the same time as shown in FIGS. At this time, the voltage VC1 at the intersection A of both switching elements receives the positive and negative DC power supply voltages + VI, -VI, and the peak value V as shown in FIG.
It will be an exchange of I. At this time, the current iD1 or iD2 is
The current is rectified by the diodes D1 and D2 through the inductance L2 and the capacitor C2, is smoothed by the capacitors C3 and C4, and flows to the load RL. When the switching element S1 is on, the diode D1 is in the forward direction.
The charge current iD1 shown in FIG.
Flow to 3. Here, the impedance of the switching element S1 and the diode D1 is sufficiently small, and C3 >> C
If the current is set to 2, the above-mentioned current becomes the inductance L2
And the capacitor C2 becomes a sinusoidal series resonance current.

When the direction of the current is reversed after a lapse of half a wave, the diode D1 becomes a reverse voltage and turns off, so that no more current flows. That is, the series resonance is automatically stopped when the half-wave of the resonance current ends and the current returns to zero. At this time, since the charge corresponding to the flowing resonance current is accumulated in the capacitor C2, the voltage VC2 between both ends remains as shown in FIG. This charge is released to the load RL when the switching element S2 is turned on next time, so that no energy loss occurs. Further, since the energy stored in the inductance is proportional to the current, the energy of the inductance L2 when the resonance stops at zero current is zero. Therefore, generation of harmful current noise is extremely small.

When the switching element S1 is turned off, the current resonance has ended, and only the current iL1 (FIG. 4D) flowing through the inductance L1 flows through the switching element S1. Since the value of the inductance L1 can be set independently of the series resonance inductance L2 and the capacitor C2, by setting L1 >> L2, the value of the current iL1 flowing through the inductance L1 becomes equal to the series resonance current i.
It can be made sufficiently smaller than D1. Therefore, the switching element S1 can be turned off with almost zero current.

[0010] On the other hand, the magnetic energy (current) stored in the inductance L1 while the switching element S1 is turned on becomes energy at which the inductance L1 and the capacitor C1 resonate in parallel. As a result, the voltage VC at point A
The value 1 decreases in a sine wave form, and eventually exceeds zero and approaches −VI. This is the voltage resonance mode. The potential at point A is -VI
When approaching, the diode D2 turns on, and the energy (current) remaining in the inductance L1 is transferred to L2, C2, D2.
2 to the capacitor C4. However, since the current of the inductance L1 is set to be small, there is no large change in current, and the potential at the point A maintains a value near -VI. Accordingly, a zero voltage operation of turning on the switching element S2 in a state where the voltage between both ends thereof is very small becomes possible, and the loss at the time of turning on can be extremely small.

When the switching element S2 is turned on, the inductance L2 and the capacitor C2 generate a negative current resonance, and a charge current iD2 shown in FIG. 4C flows to the capacitor C4 through the diode D2. Thereafter, the above-described operation is repeated according to the on / off states of the switching elements S1 and S2. In such a resonance type power supply device, since all switching operations of the switching elements are performed at zero voltage or zero current, switching loss is small and the efficiency of the entire circuit is extremely high. In addition, since both the series resonance current and the parallel resonance voltage have a spectrum close to a single frequency, the possibility of causing ringing or overshoot by interfering with the resonance dip of each part of the circuit is reduced, and unnecessary radiation such as harmonics is reduced. Very few.

FIG. 5 is a practical circuit diagram in which the series resonance circuits L2 and C2 and the parallel resonance circuits L1 and C1 are configured using the self-inductance L1 and the leakage inductance L2 on the primary side of the transformer T1. The capacitor C1 (C2) is a capacitor C1 / 2 (C2 / 2) having a half capacity
It is configured by connecting them in series. In this case, L2 and C2 are included in the voltage resonance loop, but L2 <
<L1, C2 >> C1, so in practice, L
2, the effect of C2 on voltage resonance is negligible.
A full-wave rectifier circuit 7 composed of four diodes is connected to the secondary side of the transformer T1.
3 and supplied to the load RL. The DC power supply 1 may be a DC power supply obtained by rectifying an AC power supply. In this case, the DC power supply 1 is an AC / DC converter.

The power supply device shown in FIG. 6 is of this type, in which full-wave rectification of an AC power supply AC is performed by a full-wave rectifier circuit 8 composed of four diodes, and smoothed by capacitors C5 and C6. Accordingly, here, the capacitors C5 and C6 are connected to the DC power supply 1
Becomes The two-part capacitor C1 / 2 for parallel resonance is connected in parallel to the main switching elements S1 and S2. The series resonance capacitor C2 is not divided and
It is connected in series with the next winding. The inductance L1 for parallel resonance is the self-inductance of the winding U3 of the transformer T1, and the inductance L2 for series resonance is the leakage inductance of the winding U3.

The timing control section 6 has two independent drive control circuits 61 and 62 so that the main switching elements S1 and S2 can be driven independently. Drive control circuit 6
Output stages of the drive elements Q1, Q2 are drive elements Q1, Q2.
3 and 64, and the OFF timing is controlled by the switching elements Q3 and Q4 in the preceding stage and the CR time constant circuits 63 'and 64.
'Controls. The time constant circuits 63, 63 ', 64, 6
The AC components induced in the windings U1 and U2 of the transformer T1 are positively fed back to 4 '. Drive control circuits 61 and 62
Have the same circuit configuration, but drive elements Q1,
As shown in (f) and (g) of FIG. 4, Q2 is turned on alternately with a period in which both are turned off. That is, the capacitor of the time constant circuit 63 'is charged by the current induced in the winding U1 when the element S1 is turned on. When the charged voltage rises to turn on the transistor Q3, the drive element Q1 is turned off. I do. When the element Q1 is turned off and the element S1 is turned off, the voltage applied to both ends of the primary winding is inverted due to the induction of the primary winding of the transformer T1, and the time constant circuits 64 and 64 '.
Begins to charge. Since the time constant of the circuit 64 'is larger than the time constant of the circuit 64, first, the drive element Q2 is turned on and the element S2 is turned on. Thereafter, the capacitor of the time constant circuit 64 'is completely charged, the transistor Q4 turns on, the element Q2 turns off, and the element S2 turns off. Next is the turn to turn on the element S1, but the same operation is repeated thereafter. The details of the circuit operation, except for the operation of the time constant circuits 63 and 64, are disclosed in Japanese Patent Publication No. 3-1914 filed and published by the present applicant.

FIG. 7 shows the timing control section 6 in detail. Time constant circuit 63 of drive control circuit 61
Is a resistor R11, a diode D11, and a capacitor C12.
When the charge voltage of the capacitor C12 rises beyond the base-emitter voltage of the drive element Q1, the drive element Q1 turns on. The charging time constant of the time constant circuit 63 is C12R11
It is. The time constant circuit 63 'of the drive control circuit 61
Is a resistor R10, a capacitor C10, a diode D10
And a transistor Q3, and a capacitor C1
When the charge voltage of 0 rises beyond the base-emitter voltage of the transistor Q3, the transistor Q3 turns on and turns off the drive element Q1. This time constant circuit 63 '
Is a charging time constant of C10R10, and the charging time constant of
It is set larger than 11. The oscillation frequency and duty ratio of drive element Q1 are defined by these time constants. The other drive control circuit 62 has a similar configuration,
The time constant circuit 64 includes a resistor R21, a diode D21, a capacitor C22, and a drive element Q2.
The time constant circuit 64 'includes a resistor R20, a capacitor C20,
It comprises a diode D20 and a transistor Q4. The resistor R12 and the capacitor C1 of the drive control circuit 61
1. The diode D11 forms an automatic start circuit. The same applies to the other drive control circuit 62, in which the resistor R2
2. The capacitor C21 and the diode D21 form an automatic start circuit. This automatic start circuit is designed to turn on only one of the drive elements Q1 and Q2 when the power is turned on.

The timing control section 6 is constructed as described above. The main switching elements S1 and S2 driven by the drive elements and the emitter stabilizing resistors R
1 and R2, a parallel resonance capacitor C1, a series resonance capacitor C2, a resonance inductance U3, feedback inductances U1 and U2, and the like are arranged around the timing control unit 6. In general, in order to reduce the size of such a power supply circuit, it is conceivable to incorporate all circuit components into a common HIC. However, in such a case, the presence of inductance realized by a large-capacity, high-withstand-voltage capacitor or coil is considered. Is a problem. When the circuit of FIG. 7 is put to practical use, the breakdown voltage and capacitance value of each capacitor are roughly as shown in the table below.

[0017]

[Table 1]

The capacitor C1 / 2 shown in the above table has a small capacitance but a high withstand voltage, and thus is not suitable for HIC.
Other capacitors have low withstand voltages, but all have large capacities, which are not suitable for HIC. Therefore, in the present invention, these capacitors and inductance portions are externally mounted, and the other portions are formed into HICs to reduce the size.

FIG. 1 shows the same circuit as that shown in FIG. 7 changed to an arrangement suitable for HIC implementation. The HIC unit 100 includes a resistor R
1, R2, R10, R11, R12, R20, R21,
R22 and diodes D10, D11, D20, D21
Further, only the transistors Q1 to Q4, S1 and S2 are integrated, and the capacitors C1, C2, C10, C11 and C1 are integrated.
2, C20, C21, C22 and inductance U1
U3 is configured to be externally attached. In this case,
HIC unit 1 that does not include capacitors and inductance
00 can be sufficiently reduced in size, and various power supply circuits can be configured using the common HIC unit 100 by arbitrarily setting each constant of the externally attached capacitor and inductance.

[0020]

As described above, according to the present invention, in a resonance type power supply circuit for operating a switching element, a resonance capacitor and an inductance and a switching frequency setting capacitor are externally provided, and the remaining portion is a HIC. With this configuration, it is possible to reduce the size of the entire power supply circuit by adopting the HIC, and to realize general-purpose use by arbitrarily setting external component constants.

[Brief description of the drawings]

FIG. 1 is a main part circuit diagram showing an embodiment of the present invention.

FIG. 2 is a principle configuration diagram of a resonance type power supply device.

FIG. 3 is a detailed circuit diagram showing a specific example of the circuit of FIG. 2;

FIG. 4 is an operation waveform diagram of the circuit of FIG. 3;

FIG. 5 is a circuit diagram showing a modification of the circuit of FIG. 2;

FIG. 6 is a detailed circuit diagram of a practical resonance type power supply device.

FIG. 7 is a detailed configuration diagram of a main part of FIG. 6;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... DC power supply, 2 ... Switching means, 3 ... DC output means, 4 ... Series resonance circuit, 5 ... Parallel resonance circuit, 6 ... Timing control means, 6A ... HIC conversion part, 6B ... External part, Q
1, Q2: drive element, S1, S2: main switching element, C1: parallel resonance capacitor, C2: series resonance capacitor, C10, C11, C12, C20, C2
1, C22: Drive stage switching frequency setting capacitor, U1 to U3: Inductance.

Claims (1)

(57) [Scope of request for utility model registration] 1. A switching unit comprising: a series resonance circuit and a parallel resonance circuit; a switching unit having a switching element for switching a current flowing through these resonance circuits; and a timing control unit for controlling operation timing of the switching element. In a resonance type power supply circuit that causes a series resonance with respect to a current during an on-period of the element and generates a parallel resonance with respect to a voltage during an off-period of the switching element, the series resonance circuit and the parallel resonance circuit A power supply circuit, wherein a resonance capacitor and an inductance, and a switching frequency setting capacitor of the timing control unit are externally provided, and a remaining portion is configured as a hybrid integrated circuit.