JPS58215927A - Power source - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power supply device, and more particularly to a power supply device including a plurality of switching regulators whose switching frequencies are synchronized.

Generally, various electronic devices (1) such as video tape recorders (VTRs), video cameras, etc., which are portable or mounted on vehicles, use a power source as a driving power source. This type of power supply can
The terminal voltage may fluctuate greatly, and in order to suppress such fluctuations and maintain the operation of the electronic device in a stable state, a stabilized power supply device is installed. Although a switching regulator is used in this power supply device, there are cases where a plurality of switching regulators are installed together to configure the power supply device in order to obtain an output voltage corresponding to a large number of loads.

FIG. 1 shows a conventional separately excited switching regulator used in such a power supply device. In this switching regulator, the DC human power Vi supplied between the input terminals 2A and 2B has its ripple removed by the ripple absorbing capacitor 4 installed between the input terminals 2A and 2B, and by the switching transistor 6. After being converted to AC and then converted back to DC by a DC regeneration circuit 14 consisting of a diode 8, a choke coil 10, and a capacitor 12, it is taken out as a stabilized output Vo from output terminals 16A and 16(2)B. It has become.

Resistors 18.20 are connected in series between the output terminals 16A and 16B in order to divide and extract the DC output voltage Vo, and the divided voltage output generated at the connection point of these resistors 18.20 is input to the error amplifier 22. It is compared with the reference voltage provided by the reference power supply 24, and its fluctuation is detected. This fluctuating output is applied to the non-inverting input terminal of the comparator 26, and the triangular wave output shown in FIG. 2A from the reference waveform generating circuit 28 is applied to the inverting input terminal. In FIG. 2A, Ve is the fluctuating output generated by the error amplifier 22. In FIG. That is,
When such two-person power is applied to the comparator 26,
The comparator 26 performs a pulse width modulation operation, and the pulse shown in FIG. 2B is formed, the pulse width of which is controlled by the variation. This pulse becomes a control input for the transistor 30, and in response to this switching operation, a pulsed drive current flows through the switching transistor 6 via the resistor 32 and the transistor 30, and the switching transistor 6 performs the switching operation. do. Note that the resistor 34 is a bias resistor for the switching transistor 6.

When configuring a power supply by installing multiple such switching regulators, each switching regulator requires an individual reference waveform generation circuit, which complicates the configuration and makes it difficult to match the oscillation frequency of each generation circuit. If not, it may cause extremely inconvenient beat damage. In particular, the occurrence of such beats causes noise in the oscillation and signal processing in the internal circuits of VTRs, video cameras, etc. and causes malfunctions, so it is essential to prevent such beats.

Further, the same drawback exists even when a plurality of self-excited switching regulators each having an oscillation control section are installed.

SUMMARY OF THE INVENTION An object of the present invention is to provide a power supply device that synchronizes the pulse width control section of a switching regulator and has a simplified configuration by removing a separately installed reference waveform generation circuit and the like.

(4) This invention includes a plurality of switching regulators installed together, a switching pulse generated inside one of these switching regulators, which is shaped into a waveform, and the shaped output is inputted to the pulse width control of the other switching regulator. It is characterized by being constructed from a waveform shaping circuit that provides .

Embodiments of the invention will be described in detail with reference to the drawings. FIG. 3 shows an embodiment of the power supply device of the present invention. In the figure, a plurality of switching regulators 41, 42 to 4N are installed in this power supply device, and one of the switching regulators 41, 42 to 4N is a self-excited switching regulator, and the others are passive switching regulators. Consists of a switching regulator.

The switching regulator 41 has common input terminals 52A and 52 for each switching regulator 42 to 4N.
B is formed, and the ripple absorbing capacitor 5
4 are installed. Input (5) The DC human power Vl applied to the terminals 52A and 52B has its ripple absorbed by the capacitor 54, is converted into a switching pulse by the switching transistor 56, is converted into a current by the DC regeneration circuit 58, and then The output terminals 61A and 61B output the stabilized DC output Vol. The DC regeneration circuit 58 includes a diode '62, a choke coil 64, and a capacitor 6.
The choke coil 64 of this embodiment is composed of primary and secondary coils 64P and 64S. The polarities of the primary coil 64P and the secondary coil 64S are such that the generated pulses are opposite to each other, and the switching pulse generated in the secondary coil 64S is fed back to the base of the switching transistor 56 via the differential capacitor 68. ing. That is, the differential pulse synchronized with the switching pulse via the capacitor 68 is added to the control pulse and applied to the control pulse in order to shorten the switching operation time of the switching transistor 56.

(6) A bias resistor 70 is connected between the base and emitter of the switching transistor 56, and a transistor 74 is connected to the collector of the switching transistor 56 via a resistor 72 between the base and the output side of the DC regeneration circuit 58. is connected to the base side of the switching transistor 56, and its emitter is connected to the DC reproduction output side. A feedback circuit 80 is formed between the base of this transistor 74 and the collector of the switching transistor 56 by a capacitor 76 and a resistor 78 connected in series. Bias is applied from the DC input side.

That is, the feedback circuit 8 is connected to the base of the i-Langistav 4.
Since the signal is positively fed back from the collector of the switching transistor 7 transistor 56 by 0, the transistors 56 and 74 oscillate and function as a pulse width controlled oscillator that causes a drive current to flow through the switching transistor 56. It has a function to add to the playback output.

The operation type (7) is connected to the base of this transistor 74, and a constant voltage diode 86 for setting a reference voltage is connected to the emitter of this transistor 84 with its anode on the reference potential point side, and a resistor is connected to it. A DC regeneration output is provided via 88. A DC output Vi is connected to the base of the transistor 84 from the connection point of resistors 90 and 92 connected in series between the input terminals 60A and 60B.
is applied, and this divided voltage output and the voltage regulator diode 86
The Zener voltage of the transistor 84 and the base-emitter voltage of the transistor 84 are compared with a reference voltage set as a composite value.

Further, the switching regulators 42 to 4N have a configuration excluding the feedback circuit 80 of the switching regulator 41, and have respective output terminals 62A, 62B to 6NA,
6NB as stabilized outputs Vo2 to Von having predetermined voltage values.

The switching pulse formed by the switching transistor 56 of the switching regulator 41 is
The signal is taken out from the collector and applied to the waveform shaping circuit 94. This waveform shaping circuit 94 is installed for the switching regulators 42 to 4N in order to make the switching regulator 41 function in the same manner as a conventional reference waveform generation circuit, and therefore converts it into a reference function waveform such as a triangular wave or a sawtooth wave. shall be configured to do so.

The reference waveform formed by this waveform shaping circuit 94 is applied to each switching regulator 42 to 4N transistor 74.
is applied to the base of.

In the above configuration, the operation thereof will be described. The transistor 74 for causing a drive current to flow through the switching transistor 56 oscillates because a switching pulse is positively fed back to its base. In this oscillation operation, the base current of transistor 74 is
4, and this control is dependent on the DC output. Therefore, one control pulse applied to the base of the switching transistor 56 by the oscillation of the transistor 74 becomes a pulse (9) (8) width modulation signal corresponding to the fluctuation level of the DC output, and as a result, the switching Transistor 56 switches.

Such control operations are performed continuously, and the input terminal 52A
, 52B passes through the switching transistor 56 and is converted into a switching pulse.
After 5 days from the DC regeneration circuit, it is taken out from the output terminals 6]A and 61B as a stabilized output Vol. For example, when a fluctuation occurs in the DC input due to a fluctuation in the load, the stabilization control operation described above is instantaneously performed, making it possible to continuously supply a constant DC output to the load.

In such a switching operation, the switching pulse generated at the collector of the switching transistor 6 is transmitted to the primary coil 64 . P, and a switching pulse with reversed polarity is generated in the secondary coil 64S.

This pulse is differentiated by capacitor 68 and then applied to the base of switching transistor 56. Each edge of this differential pulse corresponds to the edge portion of the switching pulse, and since the directions of increase and decrease of the potential (10) level are opposite to each other,
A switching transistor 56 functions to support ON or OFF operation. As a result,
The switching operation time of the switching transistor 56 can be shortened, and the pulses formed through the switching transistor 56 have short rise and fall times, that is, they have sharp edges.

As a result, power loss can be reduced and conversion efficiency can be improved.

Further, the switching pulse generated at the collector of the switching transistor 56 by such switching operation is applied to the waveform shaping circuit 94 and converted into a reference waveform such as a triangular wave or a sawtooth wave. This reference waveform is applied to the base of the transistor 74 of the separately excited switching regulator 42 to 4N, and serves as a pulse width control input. This control input provides similar pulse width control,
Also in the switching regulators 42 to 4N,
The DC (11) input applied to the input terminals 52A and 5'2B is converted into a switch notching pulse by the switching transistor 56, and converted to DC by the DC regeneration circuit 58, and then output from multiple channels as stabilized outputs Vo2 to Von. can be obtained.

In this way, since the switching regulators 42 to 4N are given a pulse obtained by waveform shaping the switching pulse formed by the switching transistor 56 of the switching regulator 41 as a reference waveform,
The switching frequencies will be synchronized. As a result, compared to a conventional circuit in which a reference waveform generating circuit is installed separately, there is no beat generation due to frequency deviation, and beat disturbances can be suppressed. Further, there is no need to separately provide a reference waveform generation circuit unlike the conventional circuit, and the configuration can be simplified.

FIG. 4 shows a specific embodiment of the present invention, and FIG. 5 shows its operating waveforms. In this embodiment, the waveform shaping circuit 94 is constituted by an integrating circuit composed of a resistor 96 and a capacitor 9, and the integrated output is sent to the switching regulator (12) through the switching regulator 42 or 4N transistor 74 via the capacitor 100. is applied to the base. Note that the time constant of the integrating circuit is set to a value that provides good linearity and peak value of the waveform after molding.

By configuring the waveform shaping circuit 94 in this manner, the switching pulse (not shown in FIG. 5A) generated at the collector of the switching transistor 56 of the switching regulator 41 is converted into a triangular wave shown in FIG. 5B. This triangular wave is applied via the capacitor 100 to the base of the transistor 74 of each switching regulator 42 to 4N.

Now, assuming that the control level formed by the transistor 74 is Vd (not shown in FIG. 5B), a control pulse shown in FIG. 5C is formed on the collector side of the transistor 74. Compared to the switching pulse shown in FIG. 5A, this control pulse has a phase shift between the two, but its frequency does not change, so that no problems such as beats occur.

If the waveform shaping circuit 94 is configured with an integrating circuit in this way,
The number of constituent elements is extremely small, and in addition to its simplification (13), the power supply device can be made smaller by reducing the number of elements.

In the embodiment described above, the self-excited switching regulator 41 and the waveform shaping circuit 94 constitute the reference waveform generator for the other switching regulators 42 to 4N, but the reference pulse may also be taken in from a separately-excited switching regulator. A similar effect can be obtained.

As explained above, according to the present invention, when a plurality of switching regulators are installed together, it is possible to synchronize the switching frequencies, suppress the occurrence of beats etc. that adversely affect waveform processing, and The generation of the reference waveform can be simplified, and the power supply device can also be made smaller.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram showing a conventional switching regulator, Fig. 2 is an explanatory diagram showing its operating waveforms, Fig. 3 is a circuit diagram showing an embodiment of the power supply device of the present invention, and Fig. 4 is a power supply of the present invention. Specific implementation of the device (14) A circuit diagram showing an example, and FIG. 5 is an explanatory diagram showing its operating waveforms. 41.42 or 4N...Switching regulator, 94...Waveform shaping circuit.

Claims (1)

[Claims] (11) A plurality of switching regulators installed together,
A power supply device comprising a waveform shaping circuit that shapes a switching pulse generated inside one of these switching regulators into a waveform and supplies the shaped output as a reference waveform input to another switching regulator. (2) The power supply device according to claim 1, wherein the waveform shaping circuit is constituted by an integrating circuit that integrates the switching pulse.