JPH06121537A - Full-wave rectifying circuit - Google Patents

Abstract

PURPOSE:To simplify the constitution and to reduce the cost by reducing the number of components. CONSTITUTION:An AC signal source and a DC reference power supply Vref are connected with input terminals of control transistors Q13, Q16 constituting prestage and poststage of a current mirror structure, respectively, and a resistor R2 is connected between the control transistors. Variation of output from the control transistor is taken out from prestage and poststage loads under control of transistors Q24-Q28 coupling between the prestage and poststage and the variations are combined to obtain a full-wave rectified output.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rectifier circuit, and more particularly to a full wave rectifier circuit.

[0002]

2. Description of the Related Art A conventional full-wave rectifier circuit has a structure as shown in FIG. 4, for example. In FIG. 4, Vref is a DC reference power source and OSC is a peak voltage V
1 AC signal source, Q1 to Q6 are transistors, D1
Is a diode, AP1 is an amplifier, R1 is a resistor, IS1,
IS2 is a current source and AM is an ammeter.

In such a configuration, the amplifier AP1 uses the emitter potentials of the transistors Q1 and Q3 as the reference voltage Vr.
It has the function of setting ef. The AC signal of the peak voltage V1 that changes on the reference voltage Vref is converted into a current by R1 and is transmitted to the subsequent stage as a change in the output current of the transistor Q1 or Q3, and the peak is obtained as the collector current of the transistor Q5 as shown in the figure. Current is V1 /
It is designed to be extracted as a full-wave rectified waveform of R.

[0004]

[SUMMARY OF THE INVENTION However, in such a configuration, the input impedance of the rectifier R1 becomes, the higher the output impedance source, which can result in a lower voltage. Further, the amplifier A1 that keeps the emitter voltages of the transistors Q1 and Q3 constant is required, the number of parts is large, and the cost cannot be further reduced.

[0005]

In order to solve such a problem, according to the present invention , each control transistor forming a differential input stage in which an AC signal source and a DC reference power source are connected to a current mirror stage. Are connected to the input terminals of the control transistors, and resistors are bridged between the emitters of these control transistors, and changes in the output of the control transistors are controlled under the control of the coupling circuit that connects the front and rear stages of each stage. There is provided a full-wave rectification circuit characterized in that a full-wave rectified output is obtained by taking it out from a load and combining it.

[0006]

In this way, a full-wave rectified output can be obtained without using an amplifier as in the conventional case, the number of parts can be reduced, and the cost can be reduced as compared with the conventional case.

[0007]

FIG. 1 shows an embodiment of a rectifying circuit according to the present invention . In the figure, the same components as those in FIG. 4 or those having the same function are designated by the same reference numerals.

In the figure, Q11-Q17, Q22-
Q28 is a transistor, R2 to R4 are resistors, and IS3 is a current source. The transistors Q14 and Q17 are
A current mirror stage is formed, Q13 and Q16 form a differential input stage, transistors Q12 and Q15 form a load stage, transistors Q22 and Q23 form an output stage, and transistors Q24 to Q28 form the above-mentioned transistors. A coupling circuit that couples the front and rear stages of each of the above-described stages is configured.
Then, the control transistor Q1 in the preceding stage of this differential input stage
An AC signal from an AC signal source (not shown) is supplied to the input end of the control signal Q3, and the control transistor Q16 at the rear stage of the differential input stage is supplied.
A DC reference power source Vref is connected to the input terminal of the. Then, the transistor Q1 forming the front stage of the load stage
2, a base and a collector are connected to each other, and this base is also connected to a base of a transistor Q22 that constitutes an output stage. One of the output terminals (collector) of this transistor Q22 is a transistor that similarly constitutes an output stage. Q23
Is connected to the output end (collector) of. A base and a collector of a transistor Q15, which constitutes the latter stage of the load stage, are connected to each other, and this base is also connected to the base of a transistor Q23 which constitutes the output stage. ) Is connected to the ammeter AM together with the output terminal (collector) of the transistor Q22 described above.

Further, a transistor Q1 forming a load stage
The base of 2 is a transistor Q28 which forms a coupling circuit.
Of the transistor Q15, which is connected to one of the output terminals (collector) of the
7 is connected to one of the output terminals (collector). Further, the base of the transistor Q26 is connected to one ends of the current source IS3 and the input end of the transistor Q11 together with the bases of the transistors Q14 and Q17 forming the current mirror stage. The output terminal of the transistor Q26 is connected to the transistors Q24 and Q25,
Q27 and Q28 form a current mirror via resistors R3 and R4.

In such a configuration, the point basically different from FIG. 4 is that the AC signal source OSC is connected to the input terminal of the control transistor Q13 in the preceding stage constituting the differential input stage, and the DC reference power source Vref is differential. It is connected to the input terminal of the control transistor Q16 at the rear stage of the input stage, and the output changes of the front stage and the rear stage of each stage are combined and taken out as an output, and both control transistors constituting the differential input stage. A resistor R2 is arranged to bridge between the emitters of Q13 and Q16, that is, between the connection point between the emitter of the transistor Q13 and the collector of the transistor Q14 and the connection point between the emitter of the transistor Q16 and the collector of the transistor Q17. Especially. When there is no signal, the collector current of WQ13 and Q16 and the transistor Q
The collector currents of 27 and Q28 are set to be equal.

According to this structure, the rectifier circuit input section itself functions as a high impedance element, and when an AC signal having a peak value V1 as shown in the figure is supplied to this circuit from the AC signal source OSC, Regarding the current change in the preceding stage of each stage, when there is no signal, the collector current of Q13 is supplemented by the collector current of Q28 and the collector current of Q16 is supplemented by Q27. As a result, the current flowing through Q12 and Q15 becomes zero, and the current flowing from Q22 and Q23 in the next stage to AM becomes zero. If a high level signal is sent from the signal source, the base potential of Q13 becomes high and the emitter potential of Q13 also becomes high. When this signal is V1, the collector current of Q13 is (IA + V1 / R2). Where Q
The collector current of 28 flows to Q12 due to IA. The current is (IA + V1 / R2) -IA = V1 / R2.
At this time, the collector current of Q16 is (IA-V1 / R
2) and I try to pour IA from Q27, so Q
27 becomes a saturated state, and the current flowing through Q15 becomes zero. Therefore, the current flowing through the ammeter AM is V
It becomes 1 / V2. When the signal becomes the Lo (-V1) level, the current flowing in the AM is V1 /
It becomes R2. As a result, full-wave rectification is performed.

Therefore, with such a structure, it is possible to provide a full-wave rectifier circuit which has a smaller number of parts and is simpler than the conventional one, and which is low in cost. Further, since the input impedance can be increased even with such a simple circuit configuration, it is possible to rectify even a signal source having a high output impedance with high accuracy.

FIG. 2 shows another embodiment of the present invention . 2 is different from FIG. 2 in that the transistor Q
A transistor Q31 is arranged on the input side of 13 to form a Darlington structure. With this configuration, the input impedance of the current mirror structure can be further increased.

FIG. 3 shows still another embodiment of the present invention , in which amplifiers AP2 and AP3 are added to the input sides of both control transistors Q13 and Q16 of the differential input stage.
Even in this case, the input impedance of the current mirror structure can be further increased.

In the above-described embodiment, the NPN input stage is shown, but the same operation can be performed by replacing the NPN transistor with the PNP transistor and using the circuit of the PNP input stage. NPN input is Vref
Is effective when is high, and PNP input is Vref.
Is effective when is low.

[0016]

As described above, if the full-wave rectifier circuit according to the present invention is used, the circuit configuration can be made simpler than before, the number of parts can be reduced, and the cost can be reduced. Further, since the input impedance can be made high, it is possible to accurately rectify even a signal source having a high output impedance.

[0017]

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of a full-wave rectifier circuit according to the present invention .

FIG. 2 is a circuit diagram showing another embodiment of the rectifier circuit of the present invention .

FIG. 3 is a circuit diagram showing another embodiment of the rectifier circuit of the present invention .

FIG. 4 is a circuit diagram showing an example of a conventional rectifier circuit.

[Explanation of symbols]

Q1 to Q6, Q11 to Q17, Q22 to Q28 Transistors R1 and R2 Resistance D1 Diode OSC AC signal source Vref DC reference power source IS1 to IS3 Current source AP1 to AP3 Amplifier AM Ammeter

Claims (1)

[Claims] 1. An AC signal source and a DC reference power source are respectively connected to the input terminals of respective transistors constituting a differential input stage connected to a current mirror stage, and resistors are connected between the emitters of these transistors. Along with passing, a change in the output of the transistor is extracted from the loads of the front stage and the rear stage under the control of a coupling circuit that connects the front stage and the rear stage of each stage, and a full-wave rectified output is obtained. A characteristic full-wave rectifier circuit.