JP3966999B2 - Full-wave / voltage doubler rectifier circuit - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a power supply apparatus capable of switching and selecting full-wave rectification and voltage doubler rectification of an input AC voltage.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as a DC power supply device, for example, a rectifier circuit that can be commonly used for a 100V input AC voltage and a 200V input AC voltage, that is, a device using a full-wave / double voltage rectifier circuit is known.
[0003]
FIG. 7 is a circuit diagram showing an example of such a conventional full-wave / voltage-doubler rectifier circuit, wherein 1 is an AC source, 2 is a rectifier diode circuit, 3 and 4 are smoothing capacitors, and 5 is an open / close switch.
[0004]
In the figure, the rectifier diode circuit 2 is configured by connecting four diodes 2a to 2d to a bridge, and is connected in series with the middle point of the diodes 2a and 2c connected in series with the same polarity and with the same polarity. An AC source is connected between the midpoints of the diodes 2b and 2d, and the midpoints of the diodes 2a and 2b connected in the opposite directions and the midpoints of the diodes 2c and 2d connected in opposite polarities. Two smoothing capacitors 3 and 4 are connected in series between them. An open / close switch 5 that can be turned on / off is connected between the midpoint of the diodes 2b and 2d and the midpoint of the smoothing diodes 3 and 4.
[0005]
The AC voltage from the AC source 1 is rectified by the rectifier diode circuit 2. Assuming that the open / close switch 5 is turned off, in the half cycle period of the AC voltage in which the A side is positive, the current is supplied from the AC power source 1 to the diode 2a of the rectifier diode circuit 2, the smoothing capacitors 3 and 4, and the rectifier diode circuit 2. The current flows to the AC source 1 through the diode 2d, and the AC voltage is smoothed by the smoothing capacitors 3 and 4 with the polarity shown in the figure, and in the other half cycle period in which the B side is positive, the current is supplied to the AC power source. 1 flows to the AC source 1 through the diode 2b of the rectifier diode circuit 2, the smoothing capacitors 3 and 4 and the diode 2c of the rectifier diode circuit 2, and this AC voltage is smoothed by the smoothing capacitors 3 and 4 with the same polarity as described above. .
[0006]
In this way, the AC voltage is full-wave rectified and smoothed, and a DC voltage substantially equal to the peak value of the AC voltage is obtained by the smoothing capacitors 3 and 4. That is, the circuit shown in FIG. 6 operates as a full-wave rectifier circuit.
[0007]
On the other hand, when the open / close switch 5 is turned on, during the half cycle period of the AC voltage in which the A side is positive, current flows from the AC power source 1 through the diode 2a of the rectifier diode circuit 2, the smoothing capacitor 3, and the open / close switch 5. By flowing to the source 1, this AC voltage is smoothed by the smoothing capacitor 3 with the polarity shown in the figure, and in the other half cycle period in which the B side is positive, the current is supplied from the AC power source 1 to the open / close switch 5 and smoothed. By flowing to the AC source 1 via the capacitor 4 and the diode 2 c of the rectifier diode circuit 2, this AC voltage is smoothed by the smoothing capacitor 4 with the polarity shown.
[0008]
In this way, every other half cycle of the AC voltage is rectified by the diode 2 a and smoothed by the smoothing diode 3, and every other half cycle is rectified by the diode 2 c and smoothed by the smoothing diode 4. Therefore, since the DC voltage is almost equal to the peak value in each of the smoothing capacitors 3 and 4, the smoothing capacitors 3 and 4 as a whole have a peak value of about 2 of the AC voltage. A double value of the DC voltage is obtained. That is, the circuit shown in FIG. 6 operates as a voltage doubler rectifier circuit.
[0009]
Such a full-wave / voltage-doubler rectifier circuit can be shared by the 100V system and the 200V system of AC voltage to obtain a DC voltage having the same value. That is, when a 100V AC voltage is used, the open / close switch 5 is turned on to function as a voltage doubler rectifier circuit. When a 200V AC voltage is used, the open / close switch 5 is turned off. What is necessary is just to make it function as a full wave rectifier circuit.
[0010]
[Problems to be solved by the invention]
By the way, when the conventional full-wave / voltage doubler rectifier circuit is used, the open / close switch 5 must be switched on / off depending on whether the AC voltage is 100V or 200V. Such switching is performed manually. However, when this full-wave / voltage-doubler rectifier circuit is mounted as a power supply device of a desired device, a DC voltage of a desired value can be obtained unless the open / close switch 5 is in a correct state according to the input AC voltage. Can not. For this purpose, the state of the open / close switch 5 is monitored. In addition, a technique for operating a desired function in conjunction with the state of the open / close switch 5 is also known.
[0011]
In such a case, means for detecting the on / off state of the open / close switch 5 is used. As such detection means, another switch operating in synchronization with the open / close switch 5 or an interlocking switch such as a relay switch is used. In general, the contact signal is used. However, when such a switch means is used, in order to obtain a stable detection signal, additional means such as a waveform shaping circuit are further required, which greatly increases the number of parts, increases the size of the apparatus, and increases the Costing will be incurred.
[0012]
As the open / close switch 5, it is conceivable to use a semiconductor switch that automatically turns on / off according to the magnitude of the input AC voltage, such as a hybrid IC or a module. However, such a semiconductor switch generally does not have a terminal for outputting a signal synchronized with the on / off switching. Therefore, the on / off switching of the open / close switch 5 can be performed. It is very difficult to realize a detection circuit.
[0013]
An object of the present invention is to provide a full-wave / double voltage rectifier circuit that solves such a problem and can detect switching between a full-wave rectification function and a double voltage rectification function with a simple circuit configuration. is there.
[0014]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a clamp circuit in which a diode and a capacitor are connected in series between AC input lines in the configuration of the conventional full-wave / voltage-doubler rectifier circuit. Detection means for detecting a potential relationship between the middle point of the capacitor and the negative-side output terminal of the rectifier diode circuit is provided.
[0015]
The midpoint potential with respect to the potential at the negative output terminal changes according to switching between the full-wave rectification function and the voltage doubler rectification function by switching the switch. By detecting this by the detection means, it is possible to know whether the switch is on or off, and therefore whether it is in the full-wave rectification function state or double voltage rectification function state.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0017]
FIG. 1 is a block diagram showing an embodiment of a full-wave / voltage-doubler rectifier circuit according to the present invention, wherein 6 is a clamp circuit, 7 is a diode, 8 is a capacitor, 9 is a detection circuit, and corresponds to FIG. The same reference numerals are given to the portions, and overlapping description is omitted.
[0018]
In the figure, a clamp circuit 6 is connected between AC input lines A and B. The clamp circuit 6 is composed of a series circuit of a diode 7 and a capacitor 8. The diode 7 is connected to the AC input line A side and the capacitor 8 is connected to the AC input line B side. The anode is connected to the capacitor 8.
[0019]
A detection circuit 9 is provided between the midpoint of the diode 7 and the capacitor 8 in the clamp circuit 6 and the negative output terminal of the rectifier diode circuit 2 (that is, the anodes of the diodes 2c and 2d). The detection circuit 9 detects the relationship between the potential at the midpoint C in the clamp circuit 6 and the potential at the negative output terminal D of the rectifier diode circuit 2, and thereby the open / close switch 5 is turned on or off. That is, whether this embodiment functions as a full-wave rectifier circuit or a voltage doubler rectifier circuit.
[0020]
FIG. 2 is a diagram showing a circuit configuration when the open / close switch 5 of this embodiment is turned on and functions as a voltage doubler rectifier circuit.
[0021]
When the open / close switch 5 is turned on and this embodiment functions as a voltage doubler rectifier circuit, only the diodes 2a and 2c act on the rectifier diode circuit 2, and the equivalent configuration is shown in FIG. According to such a configuration, the series circuit of the diode 2c and the smoothing capacitor 4 in the rectifier diode circuit 2 is connected in parallel to the clamp circuit 6 with the same polarity, and the same AC voltage is applied to the series circuit and the clamp circuit 6. Will be. For this reason, the potential of the middle point C of the clamp circuit 6 is equal to the potential of the negative output terminal D of the rectifier diode circuit 2. By detecting this, the detection circuit 9 determines that the open / close switch 5 is turned on and functions as a voltage doubler rectifier circuit.
[0022]
When the open / close switch 5 is turned off and this embodiment functions as a full-wave rectifier circuit, all the diodes 2a to 2d of the rectifier diode circuit 2 act, and as shown in FIG. The configuration is such that three and four series circuits are connected in parallel.
[0023]
In such a configuration, the voltage waveforms of the respective parts with reference to the potential of the negative output terminal D of the rectifier diode 2 are as shown in FIG. In the figure, D is the reference potential of the negative output terminal D of the rectifier diode 2, C is the waveform at the midpoint C of the clamp circuit 6, and E is the point on one AC input line A from the AC source 1. E represents a waveform of E, and F represents a waveform of a point F on the other AC input line B from the AC source 1.
[0024]
As shown in FIG. 4, when the potential D is used as a reference, the phases of the waveform E and the waveform F are inverted (each phase is 90 °). That is, when the potential E is at a peak, the potential F is minimized and equal to the potential D of the negative terminal D of the rectifier diode circuit 2, and when the potential F is at a peak, the potential E is minimized and the rectifier diode circuit. 2 is equal to the potential D of the negative electrode side terminal D.
[0025]
The voltage waveform C at the middle point C of the clamp circuit 6 is obtained by clamping the peak of the waveform F to the potential E (= potential D) at the point E at the peak.
[0026]
That is, when this embodiment functions as a full-wave rectifier circuit, a voltage waveform on the negative side with respect to the potential D is obtained at the point C.
[0027]
From the above, the detection circuit 9 detects the relationship between the potential at the midpoint C of the clamp circuit 6 with respect to the potential at the negative output terminal D of the rectifier diode circuit 2, so that the open / close switch 5 is turned on. Therefore, it can be determined whether this embodiment functions as a voltage doubler rectifier circuit or a full wave rectifier circuit.
[0028]
FIG. 5 is a circuit diagram showing a specific example of the detection circuit 9 in FIG. 1, in which 10 is a display element, 11 is a resistor, and parts corresponding to those in FIG.
[0029]
In the figure, here, the detection circuit 9 is constituted by a series circuit of a resistor 11 and a display element 10. As the display element 10, a neon lamp, LED, or the like can be used.
[0030]
When the open / close switch 5 is turned on and this embodiment functions as a voltage doubler rectifier circuit, the potential of the midpoint C of the clamp circuit 6 is equal to the potential of the negative output terminal D of the rectifier diode circuit 2, so that the display element 10 Does not flow, and the display element 10 does not emit light. On the other hand, when the open / close switch 5 is turned off and this embodiment functions as a full-wave rectifier circuit, the potential at the midpoint C of the clamp circuit 6 is greater than the potential at the negative output terminal D of the rectifier diode circuit 2. Therefore, in the detection circuit 9, a current flows from the negative output terminal D through the display element 10 and the resistor 11 to the middle point, and the display element 10 emits light.
[0031]
In this way, it is possible to know whether this embodiment functions as a full-wave rectifier circuit or a voltage doubler rectifier circuit by turning on and off the display element 10.
[0032]
6 is a circuit diagram showing another specific example of the detection circuit in FIG. 1, wherein 12 is a diode, 13 is a capacitor, 14 is a Zener diode, and 15 and 16 are resistors. The same reference numerals are assigned and duplicate descriptions are omitted.
[0033]
This specific example is a binary (logic level) of “H” (high level) and “L” (low label) depending on whether this embodiment functions as a full-wave rectifier circuit or a voltage doubler rectifier circuit. ) Output.
[0034]
In FIG. 6, in the detection circuit 9, a capacitor 13 and a forward diode 12 are connected in series in the direction from the negative output terminal D of the rectifier diode circuit 2 to the midpoint C of the clamp circuit 6. A power supply voltage + B is applied to the midpoint of the diode 12 via resistors 15 and 16. A Zener diode 14 is connected between the negative output terminal D and the midpoint of the resistors 15 and 16, and the Zener diode 14 is in the forward direction when viewed from the negative output terminal D.
[0035]
With such a configuration, the potential D at the negative output terminal D of the rectifier diode circuit 2 is applied to the anode of the Zener diode 14, and the divided voltage G by the resistors 15 and 16 of the power supply voltage + B is applied to the cathode. Has been.
[0036]
Assuming that the open / close switch 5 is turned on and this embodiment functions as a voltage doubler rectifier circuit, as described above, the potential D and the potential C at the midpoint C of the clamp circuit 6 are equal, and the capacitor 13 , The midpoint I of the diode 12 becomes equal to the potential D, and the diode 12 becomes non-conductive. Since the potential at the midpoint I of the capacitor 13 and the diode 12 is higher than the potential D, the Zener diode 14 is reverse-biased by the divided voltage G by the resistors 15 and 16, and the voltage across the Zener diode 14 is Voltage. The voltage across the output E ₀ of the detection circuit 9, the output E ₀ at this time is "H".
[0037]
Further, when the open / close switch 5 is turned off and this embodiment functions as a full-wave rectifier circuit, as described with reference to FIGS. 3 and 4, the midpoint potential C ≦ the negative output terminal of the rectifier diode circuit 2 This is the potential D of D. Therefore, the diode 12 becomes conductive, and the capacitor 13 is charged so that the potential I at the midpoint I between the diode 12 and the capacitor 13 is substantially equal to the lowest level of the midpoint potential C. Thus, since the potential I is lower than the potential D at the midpoint I, the divided voltage G by the resistors 15 and 16 is lowered. The ratio of the resistance values of the resistors 15 and 16 is set so that the Zener diode 14 is forward-biased by the divided voltage G, whereby the voltage across the Zener diode 14 becomes almost zero. This means that the output E ₀ of the detection circuit 9 is “L”.
[0038]
In this way, a logic level output E ₀ is obtained from the detection circuit 9, and a desired circuit (not shown) is used as a double voltage rectifier circuit by using this embodiment as a full-wave rectifier circuit. Depending on whether it is functioning, it can be controlled. Of course, the lighting of the display element may be controlled by determining the level of the output E ₀ .
[0039]
By turning on the display element as described above, it is possible to easily know whether or not this embodiment is functioning correctly with respect to the input AC voltage, and to easily correct the erroneous setting of the open / close switch 5. It becomes possible. For example, when this embodiment is used in a device having an input AC voltage of 100 V, for example, in FIG. 5, it must be operated as a voltage doubler rectifier circuit, so the display element 10 must be turned off. However, if the display element 10 is lit, the open / close switch 5 is in an off state, causing an erroneous operation, and this can be easily recognized. In this case, the open / close switch 5 may be switched to the on state.
[0040]
In this embodiment, since the on / off state is not directly detected from the open / close switch 5, the open / close switch 5 is automatically turned on / off in accordance with the input AC V voltage of the previous hybrid IC or module. A semiconductor switch that switches off can be used.
[0041]
【The invention's effect】
As described above, according to the present invention, a clamp circuit or a detection circuit having a simple configuration with a small number of parts can be used as a detection unit that functions as a full-wave rectification circuit or a voltage doubler rectification circuit. Therefore, it is not necessary to use a means that directly interlocks with the switch that performs such switching, and because it does not use a switching detection signal by a mechanical contact such as a switch, waveform shaping, etc. For this reason, a circuit for the detection is unnecessary, and detection is stable and highly reliable. In addition, it is possible to easily use switch means for automatically switching between the full-wave rectifier circuit and the voltage doubler rectifier circuit according to the input AC voltage.
[Brief description of the drawings]
FIG. 1 is a circuit diagram showing an embodiment of a full wave / voltage rectifier circuit according to the present invention.
FIG. 2 is a diagram showing a circuit configuration when functioning as a voltage doubler rectifier circuit of the embodiment shown in FIG. 1;
3 is a diagram showing a circuit configuration when functioning as a full-wave rectifier circuit of the embodiment shown in FIG. 1; FIG.
4 is a diagram showing an operation of a detection circuit in the circuit configuration shown in FIG. 3;
5 is a block diagram showing a specific example of the detection circuit in FIG. 1. FIG.
6 is a block diagram showing another specific example of the detection circuit in FIG. 1. FIG.
FIG. 7 is a circuit diagram showing an example of a conventional full-wave / voltage-doubler rectifier circuit.
[Explanation of symbols]
1 AC power supply 2 Rectifier diode circuit 3, 4 Smoothing capacitor 5 Open / close switch 6 Clamp circuit 7 Diode 8 Capacitor 9 Detection circuit

Claims (1)

A rectifier diode circuit for rectifying the input AC voltage, two smoothing capacitors for smoothing the rectified output of the rectifier diode circuit, and between the first AC input terminal of the rectifier diode circuit and the midpoint of the two smoothing capacitors A full-wave / double voltage rectifier circuit that can select a function as a full-wave rectifier circuit and a function as a voltage doubler rectifier circuit according to the on / off state of the switch. ,
A clamp circuit configured to set a potential at the second AC input terminal of the rectifier diode circuit as a clamp potential, and clamp and output an AC voltage at the first AC input terminal of the rectifier diode circuit to the clamp potential;
And detecting means for detecting an on / off state of the open / close switch by detecting a relationship between an output potential of the clamp circuit and a potential at a negative output terminal of the rectifier diode circuit. Full wave / voltage doubler rectifier circuit.

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