JPH02279006A - Rectifier circuit - 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] [Industrial application field] The present invention relates to a rectifier circuit.

[Prior Art] Conventional rectifier circuits have been devised in various ways to accurately flow input waveforms, and usually require a considerable number of elements. Furthermore, since conventional rectifier circuits are based on an amplifier configuration, they tend to have a large number of elements. For this reason, conventional! When one current path is integrated into an integrated circuit, a large area is required.

On the other hand, in some applications of the rectifier circuit, it is not always necessary to accurately rectify the input waveform, such as when detecting the amplitude of an AC waveform.

[Problems to be Solved by the Invention] However, even in such cases, conventional rectifier circuits have the problem of requiring a large area for integration. For this reason, there has been a demand for a rectifier circuit that can be constructed with a small number of elements even if it is rough.

The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a rectifier circuit that can be configured with a small number of elements.

[Means for Solving the Problems] The above object includes a first transistor whose emitter is connected to a reference power source, whose collector and base are connected, and whose base is connected to the base of the first transistor and whose emitter is a second transistor connected to the reference power supply;
a third transistor having an emitter connected to the collector of the first transistor, a collector connected to the collector of the second transistor, and a base connected to the reference power source; An AC signal is input to a connection point between the collector of the first transistor and the emitter of the third transistor, the input AC signal is rectified, and the AC signal is connected to the collector of the second transistor and the emitter of the third transistor. This is achieved by a rectifier circuit characterized in that it takes out its output from the point where the connector is connected.

[Function] According to the present invention, when the potential of the input AC signal becomes higher than the reference potential, the first transistor turns on and current flows, and conversely, when the potential of the input AC signal becomes lower than the reference potential, the third transistor turns on. It turns on and current flows. In either case, an output is obtained based on currents flowing in the same direction from the commonly connected collectors of the second and third transistors.

[Example] FIG. 1 shows a rectifier circuit according to a first embodiment of the present invention.

The rectifier circuit of this embodiment includes three npn) transistors Ql,
It is composed of five elements: Q2, Q3, and two resistors R1 and R2.

The emitter of the transistor Q1 is connected to the reference power supply VRIIP, and the collector and base are connected.

The emitter and base of transistor Q2 are connected to the emitter and base of transistor Q1.

Transistors Q1 and Q2 have the same current flowing through the other transistor as the current flowing through one transistor.
This is a so-called current mirror function f system.

The emitter of transistor Q3 is connected to the collector of transistor Q1, the collector is connected to the collector of transistor Q2, and the base is connected to reference power supply V REP.

The input AC signal VIN is input to a connection point A between the collector of the transistor Ql and the emitter of the transistor Q3 via a resistor R1.

A resistor R2 is inserted between a connection point B between the collector of the transistor Q2 and the collector of the transistor Q3 and the power supply VCC, and a rectified signal VOUT is output from the connection point B.

Next, the rectifying operation of this embodiment will be explained using the signal waveforms shown in FIG.

As shown in FIG. 2(a), the input AC signal VIN of this embodiment has a reference potential VRI? It is an AC signal centered on .

When the potential of the input signal VIN is higher than the reference potential V*tp, the transistor Q3 remains off;
The potential of IN is the threshold voltage of transistor Q1 Vl1gQ1
When the voltage becomes higher than that, the transistor Q1 turns on. Then, current flows into the transistor Q1 from the input terminal. Since the transistor Q1 and the transistor Q2 form a current mirror circuit, the transistor Q2 causes a current having the same value as the current flowing through the transistor Q1 to flow through the resistor R2.

Therefore, the output signal Voυ↑ is expressed by the following equation.

VOLI ding =vcc-[((IV@ip-
VINI-VIIKO+)/R1+Ieo+
1oot ] xR2> Vcc ((l
Vmip VINI Vsgo+)/R1)
xR, where IIIQ+ is the base current of transistor Q1, and I8.2 is the base current of transistor Q2.

When the potentials of the input signals ■ and N are lower than the reference potential VRIP, the transistor Q1 is turned off, but when the potential of the input signal I becomes lower than the threshold voltage V@tos of the transistor Q3, the transistor Q3 is turned on. Then, current flows from the reference power supply Vcc through the transistor Q3, and current flows through the resistor R2.

Therefore, the output signal ■. 〒 becomes as follows.

VouT = Vcc-[((l Vamp
VINI-V-to3)/R111sos]
xR2 = Vcc ((l Vamp VINI
Vstoi)/R11XRwhere IIQi is the base current of transistor Q3.

In this way, regardless of whether the input signal VIN becomes higher or lower than the reference potential ■RtF, the output signal ■. LIT is the second
As shown in Figure (b), the potential is always lower than the potential Vcc based on the potential Vcc, and a rectified DC signal is obtained.

Note that, as is clear from the above equation, the gain of the rectifier circuit can be changed by changing the ratio between the resistor R1 and the resistor R2.

FIG. 3 shows a rectifier circuit according to a second embodiment of the invention.

In the first embodiment, the resistor R2 was inserted between the connection point B and the reference power supply ■cC, and the output was obtained as a voltage, but in this embodiment, the output was obtained as a current between the connection point B and the reference power supply Vcc. I'm trying to take it out.

A pnp transistor Q is connected between the connection point B and the reference power supply Vcc.
The emitter of this transistor Q4 is connected to the reference power supply Vcc, and the collector and base are connected to the connection point B. The emitter and base of the pnp transistor Q5 are connected to the emitter and base of the transistor Q4, respectively, forming a current mirror circuit. A resistor R3 is inserted between the transistor Q5 and the reference power supply ■■r, and a DC signal V is rectified from one end of the resistor R3. U
〒 is output.

When the potential of the input signal VIN becomes higher than the reference potential Vat- by the threshold voltage VaIQ+ of the transistor Q1, the transistor Q1 is turned on. Then, the current flowing into the transistor Q1 from the input terminal flows into the transistor Q4.

When the potential of the input signal ■ becomes lower than the reference potential V□2 by more than the threshold voltage Vstos of the transistor Q3, the transistor Q3 is turned on. Then, the current flowing from the reference power supply Vac through the transistor Q3 flows into the transistor Q4.
flows to

In this way, a current flows in the same direction through the transistor Q4 regardless of whether it is higher or lower than the reference potential vRo of the input signal (2). That is, a rectified current is obtained.

Since a current mirror circuit is configured, the same current as that of transistor Q4 flows through transistor Q5 and resistor R3. Therefore, as shown in FIG. 4(b), the reference voltage V
■Always higher output than RIF. 07 is obtained.

FIG. 5 shows a rectifier circuit according to a third embodiment of the present invention.

In the first embodiment, a voltage lower than the potential ■cc was used as a reference, but in this embodiment, a voltage higher than the potential Vat is used as a reference.

The rectifier circuit of this embodiment also includes three pnp transistors Q6,
It is composed of five elements: Ql, Q8, and two resistors R4 and R5. The emitter of the transistor Q6 is connected to the reference power supply v2, and the collector and base thereof are connected. The emitter and base of the transistor Q7 are connected to the emitter and base of the transistor Q6, respectively, and the transistors Q6 and Ql form a current mirror circuit. The emitter of transistor Q8 is transistor Q6
The collector is connected to the collector of the transistor Q7, and the base is connected to the reference power source ■FIEF.

The input AC signal VIN is input to a connection point C between the collector of the transistor Q6 and the emitter of the transistor Q7 via a resistor R4. The connection point between the collector of transistor Q7 and the collector of transistor Q8 and the power supply VtW
A resistor R5 is inserted between the two, and 700 rectified signals are output from the connection point.

When an AC output VIN is input with reference to the reference potential VRtF as shown in FIG. 6(a), a DC output V as shown in FIG. 6(b) is generated. LIT is obtained. Note that the operation of this embodiment is also similar to that of the first embodiment, so detailed explanation will be omitted.

The present invention is not limited to the above-mentioned embodiments, and various modifications are possible.

For example, in the third embodiment, the output is taken out as a voltage, but the output may be taken out as a current as in the second example.

[Effects of the Invention] As described above, according to the present invention, a rectifier circuit can be configured with an extremely small number of elements, so it can be integrated into a circuit with a small area. It was possible to create an integrated circuit with one-half to one-third the area compared to the case where the circuit was integrated.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a rectifier circuit according to a first embodiment of the present invention, FIG. 2 is a signal waveform diagram of the rectifier circuit, and FIG. 3 is a circuit diagram of a rectifier circuit according to a second embodiment of the present invention. FIG. 4 is a signal waveform diagram of the rectifier circuit, FIG. 5 is a circuit diagram of a rectifier circuit according to a third embodiment of the present invention, and FIG. 6 is a signal waveform diagram of the rectifier circuit. In the figure, Ql, Q2, Q3--n p n transistor R
1, R2...Resistor Q4, Q5...PNP transistor R3...Resistor Q6, Ql, Q8...-PNP transistor R4, R5...
...Resistance (b)

Claims (1)

[Claims] A first transistor whose emitter is connected to a reference power source, and whose collector and base are connected; the base is connected to the base of the first transistor, and the emitter is connected to the reference power source. a second transistor; and a third transistor, the emitter of which is connected to the collector of the first transistor, the collector of which is connected to the collector of the second transistor, and the base of which is connected to the reference power supply; An AC signal centered on the reference power source is input to a connection point between the collector of the first transistor and the emitter of the third transistor, the input AC signal is rectified, and the input AC signal is input to the second transistor. A rectifier circuit characterized in that an output is taken out from a point where a collector and a connector of a third transistor are connected.