JPH01116454A - Full-wave rectifying circuit - Google Patents

Abstract

PURPOSE:To reduce a time constant of a peak holding circuit at the rear stage of a full-wave rectifying circuit to a half than ever by arranging first and second transistors to convert an input signal into current values through detection of its peak and bottom values CONSTITUTION:When a sine wave signal is inputted into an input terminal, current flowing through a transistor 1(2) increases or decreases according to the size of an input signal from the time when a potential at a point A reaches a value enough to make the transistor 1(2) conduct if at a positive (negative) level. The peak value of the current corresponds to a peak value (bottom value) of an input signal. A transistor 2(1) is turned OFF as a potential difference between the base and emitter thereof falls below a value enough to make it conduct. By repeating this operation at the positive or negative level, a current waveform develops at a point of B as illustrated. A change in the current is extracted as change in a voltage with a resistance 5 to detect a peak value and a bottom value of the input signal, thereby achieving full-wave rectification.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a full-wave rectifier circuit.

[Conventional technology]

FIG. 2 shows an example of a conventional half-wave rectifier circuit, in which the voltage source 15 has a voltage value that turns off the transistor 11 when there is no input signal.
3.14 is resistance.

When a signal as shown in FIG. 3 is input to the input terminal, the transistor 11 changes depending on the magnitude of the input signal from the point at which the potential at point A reaches a potential sufficient to make the transistor 11 conductive.
The current flowing through increases and decreases. At this time, a current waveform as shown in FIG. 5 appears at point B, and by extracting this current change as a voltage change at the resistor 14, the input signal is half-wave rectified.

[Problem that the invention seeks to solve]

The conventional half-wave rectifier circuit described above detects only the peak value of the input signal and does not operate on the bottom value.
There is a drawback that the time constant of the peak holding circuit connected to the subsequent stage of the circuit needs to be increased.

An object of the present invention is to provide a full-wave rectifier circuit that eliminates the above-mentioned drawbacks.

[Means for solving problems]

The present invention is a full-wave rectifier circuit that detects the maximum and minimum values of an input signal, and includes a first transistor that detects the peak value of the input signal and converts it into a current value, and a first transistor that detects the bottom value. This is a full-wave rectifier circuit characterized by comprising a second transistor that converts the current into a current value.

【Example〕

1 shows an embodiment of the present invention, the present invention consists of two transistors 1 and 2, two voltage sources 6 and 7 connected between the base and emitter of each transistor, a capacitor 3, and a resistor. 4, 5, both transistors 1, 2
is connected between the collectors of
is extracted as a voltage change.

Voltage sources 6 and 7 are set to voltage values that turn off transistor 1 and transistor 2 when there is no input signal.

When a signal as shown in Fig. 3 is input to the input terminal, if it is a positive level signal, from the time when the potential at point A reaches a potential sufficient to make transistor 1 conductive, depending on the magnitude of the input signal, The current flowing through transistor 1 increases or decreases. The peak value of this current corresponds to the peak value of the input signal. At this time, the potential difference between the base and emitter of the transistor 2 becomes less than a value sufficient for conduction, so that the transistor 2 is turned off.

Further, when a negative level signal is input, the current flowing through the transistor 2 increases or decreases depending on the magnitude of the input signal from the time when the potential at the point A becomes a potential sufficient to make the transistor 2 conductive. The peak value of this current becomes the bottom value of the input signal. At this time, the potential difference between the base and emitter of the transistor 1 becomes less than a value sufficient for conduction, so that the transistor 1 is turned off.

By repeating the above operation, the fourth point will be placed at point B in Figure 1.
A current waveform as shown in the figure appears.

This current change is taken out as a voltage change by a resistor 5, the peak value and bottom value of the input signal are detected, and full-wave rectification is performed.

〔Effect of the invention〕

As explained above, the present invention has a configuration that detects the peak value and bottom value of the input signal, so that the time constant of the peak holding circuit connected after the present full-wave rectifier circuit can be reduced to 172 compared to the conventional circuit. There is an effect that can be done.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing an embodiment of the present invention, Fig. 2 is a circuit diagram showing a conventional half-wave rectifier circuit, Fig. 3 is a diagram showing the input voltage waveforms of Figs. Figure 4 shows the current waveform at point B when the waveform in Figure 3 is input to the circuit of the present invention, and Figure 5 shows the current waveform at point B.
The figure shows a current waveform at point B when the waveform shown in FIG. 3 is input to a conventional circuit.

Claims (1)

[Claims] (1) In a full-wave rectifier circuit that detects the maximum and minimum values of an input signal, the first transistor detects the peak value of the input signal and converts it into a current value, and the first transistor detects the bottom value and converts it into a current value. A full-wave rectifier circuit comprising: a second transistor that converts into a current value.