JP2539158Y2 - DC power supply - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a DC power supply device that can receive a first voltage and a second voltage twice as much as the first voltage.

[Conventional technology]

A DC power supply device in which a switching regulator is connected to a commercial AC power supply via a rectifier circuit is known. When this type of device is connected to a 100 V AC power supply, for example, the boost ratio is set to three times, and when it is connected to a 200 V AC power source, the boost ratio is set to 1.5 times. This makes it possible to obtain a constant DC output voltage regardless of changes in the input voltage.

[Problems to be solved by the invention]

By the way, when the boosting ratio of the switching regulator increases, the passing power of the switching element and the like increases, and the switching loss increases.

SUMMARY OF THE INVENTION An object of the present invention is to provide a DC power supply that does not need to change the voltage conversion ratio even when the input voltage is switched.

[Means for solving the problem]

The device according to claim 1 for achieving the above object has the following features.
And a second AC voltage twice as large as the first value.
And a pair of AC input terminals to which the AC voltage is alternatively supplied, and whichever of the first and second AC voltages is applied to the pair of AC input terminals. A pair of DC output terminals required to transmit the same DC output voltage, and a first for passing only a positive half-wave of an AC voltage connected to one of the pair of AC input terminals. A diode, a second diode connected to one of the pair of AC input terminals for passing only a negative half-wave of an AC voltage, a cathode of the first diode, and the other of the pair of AC input terminals And a positive DC output is provided to one of the pair of DC output terminals with respect to the other AC input terminal, and the first and second AC input terminals are connected to the pair of AC input terminals. Which AC voltage is marked A first voltage conversion circuit configured to convert a voltage level different from a voltage of the positive half-wave have the same voltage conversion ratio be, the second
The diode is connected to an anode of the diode and the other AC input terminal, and is formed so as to provide a negative DC output to the other of the pair of DC output terminals with reference to the other AC input terminal; and To the AC input terminal
And a second voltage conversion circuit configured to convert the negative half-wave voltage to a different voltage level with the same voltage conversion ratio regardless of which of the second AC voltage is applied; A third anode having an anode connected to the other AC input terminal and a cathode connected to the one DC output terminal;
And a fourth diode whose anode is connected to the other DC output terminal, and whose cathode is connected to the other AC input terminal, are connected in series with each other,
And a first and second capacitor connected between the pair of DC output terminals, a mutual connection point of the third and fourth diodes, and a mutual connection of the first and second capacitors. And is turned on when the first AC voltage is applied to the AC input terminal, and is turned off when the second AC voltage is applied to the AC input terminal. The present invention relates to a DC power supply device including a voltage switch.

In the invention according to claim 2, there is a possibility that the first AC voltage having the first value and the second AC voltage having a second value twice as large as the first value are supplied alternatively. A pair of AC input terminals, and whether any of the first and second AC voltages are applied to the pair of AC input terminals, it is required to transmit the same DC output voltage. A pair of DC output terminals, a positive terminal connected to the pair of AC input terminals and generating a voltage corresponding to a positive half-wave of the AC voltage applied to the pair of AC input terminals, A rectifier circuit having a negative terminal that generates a voltage corresponding to a negative half-wave, an intermediate terminal that takes an intermediate potential between the positive terminal and the negative terminal, and a positive terminal connected to one of the pair of DC output terminals. An output terminal and a negative output terminal connected to the other of the pair of DC output terminals; An intermediate output terminal, the positive output terminal and the intermediate output terminal by converting the voltage of the positive half-wave obtained between the positive terminal and the intermediate terminal of the rectifier circuit to different levels, Between the negative output terminal and the intermediate output terminal by converting the voltage of the negative half-wave obtained between the negative terminal and the intermediate terminal of the rectifier circuit to a different level. And a voltage that is configured to operate at substantially the same voltage conversion ratio regardless of whether the first or second AC voltage is applied to the pair of AC input terminals. A conversion circuit, a first diode having an anode connected to the intermediate output terminal, a cathode connected to the positive output terminal, an anode connected to the negative output terminal, and a cathode connected to the intermediate output terminal. The second Daioh A first and a second capacitor connected in series with each other and connected between the positive output terminal and the negative output terminal; a mutual connection point of the first and second diodes; The first and second capacitors are connected between mutual connection points, and are turned on when the first AC voltage is applied to the AC input terminal, and the second input terminal is connected to the AC input terminal. The present invention relates to a DC power supply device having a voltage switch that is turned off when an AC voltage is applied.

[Action]

In the invention of any claim, the voltage conversion ratio is kept substantially constant irrespective of the switching of the input voltage. Therefore, it is possible to convert a voltage to a different level with an efficient voltage conversion ratio.

First Embodiment Next, a DC power supply device according to a first embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. This device has a pair of AC input terminals 1 and 2 to which AC voltages of 100 V and 200 V are selectively supplied. The high-frequency removing filter 3 connected to the input terminals 1 and 2 includes reactors 4 and 5 connected in series to the lines, and capacitors 6 and 7 connected between a pair of lines.

A first diode 9 as a first rectifier and a second diode 10 as a second rectifier are connected to one power supply line 8 of the output stage of the filter 3. The first and second diodes 9 and 10 are connected to polarities opposite to each other. Therefore, the first and second diodes 9 and 10 form a rectifier circuit having a positive terminal, a negative terminal, and an intermediate terminal.

A first voltage conversion circuit 12 is connected to a line 11 on the output side of the first diode 9. First voltage conversion circuit 12
A first reactor 13 for energy storage, a first switching block 14, a first current detection resistor 15,
, And a first backflow preventing diode 17. The first reactor 13 and the first reverse current blocking diode 17 are connected in series to the line 11, and the first switching element 14 and the first current detection resistor 15 are connected between the output terminal of the reactor 13 and the filter 3. Connected to the output line 18 on the side.

The second voltage conversion circuit 20 connected to the anode side line 19 of the second diode 10 includes a second reactor 21, a second switching element 22, a second current detection resistor 23,
It comprises a second control circuit 24 and a second reverse current blocking diode 25. The second reactor 21 and the second reverse current blocking diode 25 are connected in series to the line 19, and the second switching element 22 and the second current detecting resistor 23 are connected to the output terminal of the second reactor 21 and the intermediate line 18 respectively. Is connected between.

The first and second switching elements 14, 22 are respectively FE
T and is turned on by a pulse width modulation (PWM) pulse having a repetition frequency sufficiently higher than the frequency of the AC power supplied from the control circuits 16 and 24 (at least several times the power supply frequency, for example, 20 kHz).・ It is driven off.

Note that the first and second voltage conversion circuits 12 and 20 can be considered as one voltage conversion circuit having a positive output terminal, a negative output terminal, and an intermediate output terminal.

A voltage doubler circuit 28 having a voltage switching function is connected between the first and second reverse current blocking diodes 17, 25 and the pair of DC output terminals 26, 27. The voltage doubler circuit 28 includes two diodes 2 connected between a pair of output terminals 26 and 27.
9 and 30, two capacitors 31 and 32, and a switch 33. One diode 29 is connected between the intermediate line 18 and one output terminal 26, the other diode 30 is connected between the other output terminal 27 and the intermediate line 18, and the two capacitors 31, 32 are paired. Are connected in series with each other between the output terminals 26 and 27. The voltage doubler switch 33 includes a connection point 34 between the two diodes 29 and 30 and two capacitors 31 and 32.
Are connected between the connection middle point 35 and the ON operation at the time of the double voltage operation, and the OFF operation at the time of the non-double voltage operation.

The first control circuit 16 is connected to a voltage detection circuit 36 connected to the output terminals 26 and 27 via a line 36a, and is also connected to a current detection line 37 derived from one end of the current detection resistor 15. The output line 38 is connected to the control terminal (gate of the FET) of the switching element 14. The second control circuit 24 is also connected to the voltage detection circuit 36 by a line 36b, and is also connected to a current detection line 39 derived from one end of the second current detection resistor 23. Is connected to the control terminal of the switching element 22.

Since the first and second control circuits 16 and 24 have the same configuration, only the first control circuit 16 is shown in FIG. The control circuit 16 includes a differential amplifier 41, a reference voltage source 42, a voltage comparator 43, a triangular wave generating circuit 44, a synthesizing circuit 45a, a set trigger signal forming circuit 45, a reset trigger signal forming circuit 46, a flip-flop, Consists of 47. Differential amplifier
One input terminal of 41 is connected to the voltage detection line 36a,
Since the other input terminal is connected to the reference voltage source 42,
A voltage corresponding to the difference between the detection voltage and the reference voltage is obtained at this output terminal. The triangular wave generation circuit 44 generates a triangular wave (sawtooth wave) with a period in which the period of the AC voltage is sufficiently short. The synthesizing circuit 45a includes resistors 48 and 49, and synthesizes the output of the differential amplifier 41 and the triangular wave of the triangular wave generating circuit 44 to generate a comparator.
43 to one input terminal. Since the current input line 37 is connected to the other input terminal of the comparator 43,
In the comparator 43, the detected current value is compared with the voltage-corrected triangular wave. The triangular wave has a slope whose amplitude decreases with time, while the current detection resistor
Since the current flowing through 15 has a slope that increases with time due to the action of the inductor 13, there occurs a point in time when the amplitude of the current detection waveform matches the amplitude of the triangular wave, and the output state of the comparator 43 changes here. A set trigger signal forming circuit is provided at the set terminal S of the flip-flop 47.
A trigger signal synchronized with the triangular wave is applied from 45, and a reset trigger signal synchronized with the conversion of the output of the comparator 43 is applied to the reset terminal R from the reset trigger signal forming circuit 46. Therefore, a square wave can be obtained at the output terminal Q of the flip-flop 47 at the same cycle as the triangular wave, and the switching element 14 turns on and off in response to this.

〔motion〕

In FIG. 1, for example, 100 V
When the AC voltage is supplied, the double voltage switch 33 is turned on. The switch 33 may be manually turned on and off, or an input voltage discriminating circuit may be connected to the input terminals 1 and 2 to discriminate between the first AC voltage and the second AC voltage. May be turned on and off automatically. During the period of the positive half-wave of the AC voltage (0 to 180 degrees) while the switch 33 is on, the line 8, the first diode 9, the first reactor 13, and the first switching element
A current flows in a circuit consisting of 14, a first current detection resistor 15, and a line 18. The first switching element 14 is turned on and off a plurality of times during a positive half-wave period (180 degrees). The energy accumulated in the reactor 13 during the ON period of the first switching element 14 includes the first reactor 13, the first reverse current blocking diode 17, the first voltage doubler and smoothing capacitor 31, and the switch 33. , And is transferred to the capacitor 31 by the circuit including the intermediate line 18. Thereby, the capacitor 31 is charged to the output voltage of the first voltage conversion circuit 12. Period of negative half-wave of AC voltage (180-360 degree section)
Now, the intermediate line 18, the second switching element 22,
The second current detection resistor 23, the second reactor 21, and the second
A current flows in a circuit consisting of the diode 10 and the line 8. The energy stored in the second reactor 21 during the ON period of the second switching element 22 is applied to the second reactor 21, the second diode 10, the line 8, the reactor 4, and the input terminals 1, 2. Connected power supply (not shown)
, An intermediate line 18, a switch 33, a second voltage doubler and smoothing capacitor 32, and a second reverse current blocking diode 25.
Flows in the circuit consisting of Thereby, the capacitor 32 is charged with a voltage corresponding to the output voltage of the second voltage conversion circuit 20. Since the two capacitors 31 and 32 are connected in series with each other, a DC output voltage equal to the sum of the voltages of the two capacitors 31 and 32 can be obtained between the pair of output terminals 26 and 27. That is, when the capacitors 31 and 32 are charged to 210 V by the boosting type voltage conversion circuits 12 and 20, respectively, 420 V of the sum is obtained between the output terminals 26 and 27.

On the other hand, when a second power supply of 200 V is connected to the input terminals 1 and 2, the switch 33 is turned off so that the voltages of the output terminals 26 and 27 become the same as those at the time of 100 V. At this time, the step-up ratios of the first and second voltage conversion circuits 12 and 20 are kept the same as in the case of 100V. As a result, the first and second voltage conversion circuits 12, 20
Output voltage is 420V which is twice that at 100V. The output current of the first voltage conversion circuit 12 is a capacitor 31 and a capacitor 32
Flows into the circuit consisting of
The voltages of 1 and 32 are each 210V. The output current of the second voltage conversion circuit 20 includes a diode 29, a capacitor 31,
Flows into the circuit consisting of the capacitor 32 and the capacitors 31 and 32
Are charged to 210V. Therefore, 420 V can be obtained at the output terminals 26 and 27 as in the case of 100 V AC.

Keeping the step-up ratio of the voltage conversion circuits 12 and 20 substantially constant irrespective of the change in the input voltage means that the first and second switching elements 1 and 2 are switched even when the input voltage is switched.
This means that it is not necessary to switch the duty in steps 4 and 22. Therefore, it is possible to operate the first and second switching elements 14 and 22 at a duty that can obtain high efficiency.

Note that no smoothing capacitor is provided at the input stage of the first and second voltage conversion circuits 12 and 20. Therefore, the pulsating current is supplied to the voltage conversion circuits 12 and 20. Since the first and second switching elements 14 and 22 interrupt the pulsation, the amplitude of the current flowing during the interruption changes according to the amplitude of the pulsation. Therefore, the waveform of the current flowing through the input terminals 1 and 2 can be approximated to a sine wave.

Second Embodiment Next, a DC power supply according to a second embodiment will be described with reference to FIG. However, in FIG. 3, substantially the same parts as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. The circuit of FIG. 3 has an energy storage reactor 50 shared by the intermediate line 18 for the positive half wave and the negative half wave.
This reactor 50 is the first and second reactors in FIG.
It has the same function as 13 and 21. Therefore, the same operation and effect as in FIG. 1 can be obtained by the circuit in FIG.

(Modification)

The present invention is not limited to the above-described embodiment, and for example, the following modifications are possible.

(1) The voltage conversion circuit 12 may be configured as shown in FIG. In FIG. 5, a transformer primary winding 13a and a secondary winding 13b are provided instead of the reactor 13, and a primary winding 13a is provided.
a is connected in series with the switching element 14, and the secondary winding 13b
Are connected in series to the DC line. Note that the voltage conversion circuit 20 can be configured in the same manner as in FIG.

(2) The voltage conversion circuit 12 may be configured as shown in FIG. In FIG. 6, the switching element 14 is connected to the DC line 11
, And a reactor 13 is connected between the DC lines 11 and 18. The direction of the diode 17 is opposite to that in FIG. In this case, not only the boost but also the buck is possible. Note that the voltage conversion circuit 20 can also be configured in the same manner as in FIG.

(3) The voltage conversion circuit 12 may be configured as shown in FIG. In FIG. 7, a transformer primary winding 13a and a secondary winding 13b are provided instead of the reactor of FIG. 1, and are isolated from each other. Note that the voltage conversion circuit 20 can be configured in the same manner as in FIG.

(4) The voltage conversion circuit 12 may be configured as shown in FIG. FIG. 8 is obtained by adding a diode 53 and a reactor 54 to the circuit of FIG. The voltage conversion circuit
20 can be configured in the same manner as in FIG.

(5) The control circuit 16 is not limited to that shown in FIG. 2 and can be variously modified. For example, the output of the differential amplifier 41 and the triangular wave may be compared by a comparator to form a PWM pulse.

(6) To improve the waveform of the input current,
It is desirable to supply a pulsating current without connecting a smoothing capacitor to the output stage, but a smoothing circuit may be provided before the voltage conversion circuits 12 and 20 when waveform improvement is not required.

[Effect of the invention]

According to the present invention, the conversion ratio of the voltage conversion circuit can be kept constant irrespective of the switching of the AC input voltage, and the voltage conversion circuit can be operated with high efficiency.

[Brief description of the drawings]

1 is a circuit diagram showing a DC power supply according to a first embodiment of the present invention, FIG. 2 is a block diagram showing a control circuit of FIG. 1, and FIG. 3 is a DC power supply according to a second embodiment. FIG. 4, FIG. 5, FIG. 6, and FIG. 7 are circuit diagrams showing modified examples of the voltage conversion circuit. 1, 2, ... input terminal, 9 ... first diode, 10 ...
2nd diode, 12 ... 1st voltage conversion circuit, 20 ...
Second voltage conversion circuits, 26, 27... Output terminals.

Claims (2)

(57) [Scope of request for utility model registration] A pair of AC input terminals to which a first AC voltage having a first value and a second AC voltage having a value twice as large as the first value may be supplied alternatively. A pair of DC output terminals required to transmit the same DC output voltage, regardless of whether the first or second AC voltage is applied to the pair of AC input terminals. A first diode connected to one of the pair of AC input terminals for passing only a positive half-wave of an AC voltage; and a negative half of an AC voltage connected to one of the pair of AC input terminals. A second diode for passing only waves, a cathode connected to the first diode and the other of the pair of AC input terminals, and a positive DC output based on the other AC input terminal. Formed to be applied to one of the pair of DC output terminals. Also, regardless of which of the first and second AC voltages is applied to the pair of AC input terminals, the positive half-wave voltage is converted to a different voltage level with the same voltage conversion ratio. A first voltage conversion circuit configured, connected to an anode of the second diode and the other AC input terminal, and outputs a negative DC output with respect to the other AC input terminal to the pair of the first and second AC input terminals. The negative half-wave is formed so as to be applied to the other of the DC output terminals and has the same voltage conversion ratio regardless of whether the first or second AC voltage is applied to the pair of AC input terminals. A second voltage conversion circuit configured to convert the first voltage to a different voltage level, a third voltage conversion circuit having an anode connected to the other AC input terminal and a cathode connected to the one DC output terminal. And the diode A fourth diode connected to the other DC output terminal, a cathode connected to the other AC input terminal, connected in series with each other, and connected between the pair of DC output terminals. The first and second capacitors are connected between a mutual connection point of the third and fourth diodes and a mutual connection point of the first and second capacitors; A voltage switching switch that is turned on when the first AC voltage is applied to the input terminal and turned off when the second AC voltage is applied to the AC input terminal. 2. A pair of first AC voltages having a first value and a second AC voltage having a second value twice as large as the first value. An AC input terminal, and a pair of DCs required to transmit the same DC output voltage, regardless of which of the first and second AC voltages is applied to the pair of AC input terminals. An output terminal, a positive terminal connected to the pair of AC input terminals to generate a voltage corresponding to a positive half wave of the AC voltage applied to the pair of AC input terminals, and a negative half wave of the AC voltage A rectifier circuit having a negative terminal that generates a voltage corresponding to the rectifier circuit, an intermediate terminal having an intermediate potential between the positive terminal and the negative terminal, a positive output terminal connected to one of the pair of DC output terminals, and Negative output terminals connected to the other of a pair of DC output terminals and their intermediate output terminals The positive half-wave voltage obtained between the positive terminal and the intermediate terminal of the rectifier circuit is converted to a different level and applied between the positive output terminal and the intermediate output terminal. Forming the voltage of the negative half-wave obtained between the negative terminal and the intermediate terminal of the rectifier circuit to a different level and applying the converted voltage between the negative output terminal and the intermediate output terminal. And a voltage conversion circuit formed to operate at substantially the same voltage conversion ratio regardless of which of the first and second AC voltages is applied to the pair of AC input terminals; A first diode having an anode connected to the intermediate output terminal and a cathode connected to the positive output terminal; and a second diode having an anode connected to the negative output terminal and a cathode connected to the intermediate output terminal. Diodes and each other First and second capacitors connected to a column and connected between the positive output terminal and the negative output terminal; a mutual connection point of the first and second diodes; The second capacitor is connected between the mutual connection points of the second capacitors, is turned on when the first AC voltage is applied to the AC input terminal, and the second AC voltage is applied to the AC input terminal. And a voltage switching switch that is turned off when the voltage is applied.