JP3605022B2 - Phase comparison circuit - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a phase comparison circuit that extracts a signal corresponding to a phase difference between two input signals from two input signals using a multistable circuit.
[0002]
[Prior art]
Conventionally, the phase comparison circuit shown in FIG. 8 has been used. This is composed of a logic EXOR circuit constituted by using field effect transistors Q1 to Q7 and load resistors RL1 and RL2. As shown in FIG. 9, two signals Vin1 and Vin2 correspond to both signals Vin1 and Vin2. When Vin2 does not match, the high level signal VH is output, and when they match, the low level signal VL is output as the output signal Vout.
[0003]
[Problems to be solved by the invention]
However, this circuit has a problem that the number of elements is large and the constant current source transistor Q7 is used, so that the power consumption is large and the input signal requires a large amplitude.
[0004]
An object of the present invention is to provide a phase comparison circuit that can reduce the number of elements, reduce power consumption, and operate stably even with a small input signal.
[0005]
[Means for Solving the Problems]
For this purpose, a first invention is a phase comparison circuit that receives two signals and extracts a signal corresponding to a phase difference between the two signals, the first comparison terminal having a first input terminal, a second input terminal, and an output terminal. When the signal at the input terminal of the second input terminal has the first value, one of a plurality of stable states is exhibited according to the relationship between the signal of the first input terminal and the threshold value, and the one of the plurality of stable states is displayed. A signal having a value corresponding to a stable state is output to the output terminal, and when the second input signal has a second value, the plurality of stable signals are output regardless of the signal of the first input terminal. It is configured to exhibit a specific one of the stable states and output a signal having a value corresponding to the specific one of the stable states to the output terminal.
[0006]
A second invention according to the first invention, comprises a transistor connected between the output terminal and the power supply terminal, and a negative resistance element connected between the output terminal and the second input terminal. The first input terminal is connected to the gate or the base of the transistor.
[0007]
In a third aspect based on the first aspect, a first transistor connected between the output terminal and a first power supply terminal; a negative resistance element having one end connected to the output terminal; A second transistor connected between the other end of the resistance element and a second power supply terminal, wherein the first input terminal is connected to a gate or a base of the first transistor; And the second input terminal is connected to the gate or base.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a block diagram of a phase comparison circuit according to an embodiment of the present invention. This phase comparison circuit has a first input terminal 11 to which a first input signal Vin1 is input and a second input terminal 12 to which a second input signal Vin2 is input, and outputs the output signal Vout. It comprises a multistable circuit 10 having an output terminal 13 for outputting.
[0009]
The multi-stable circuit 10 has human output characteristics as shown in FIGS. 2A and 2B depending on whether the value of the input signal Vin2 is V1 or V2 (V1 <V2). That is, when Vin2 = V1, there is one stable state as shown in FIG. At this time, the output signal Vout is fixed at the low level VL regardless of the value of the input signal Vin1. On the other hand, when Vin2 = V2, the multistable circuit 10 has characteristics as shown in FIG. That is, the input signal Vin1 has bistability such that the output signal Vout is VH or VL in a constant voltage region (Vin1 <Vt) (Vt: threshold), and is output in another voltage region (Vin1> Vt). This results in a monostable state where the signal Vout becomes VL.
[0010]
As described above, when the input signal Vin1 changes from V1 to V2 when the input signal Vin1 is Vin1 <Vt, the output signal Vout changes from VL to VH. Thereafter, when Vin2 = V2, if the input signal Vin1 exceeds the threshold value Vt, the output signal Vout changes to VL, and thereafter, even if the input signal Vin1 changes, Vout = VL does not change.
[0011]
Here, it is assumed that the two input signals Vin1 and Vin2 are pulse signals and are input with a phase difference as shown in FIG. When Vin2 changes from V1 to V2 when Vin1 <Vt, Vout rises from VL to VH. After that, when the value of Vin1 exceeds Vt, Vout falls to VL. That is, it can be seen that an output signal Vout having a pulse width corresponding to the phase difference between the two input signals Vin1 and Vin2 is obtained.
[0012]
The multistable circuit 10 performing the above operation can be realized by a circuit configuration as shown in FIG. 4, for example. This multistable circuit 10 includes a negative resistance element ND1 such as a resonant tunneling diode and an Ezaki diode and a field effect transistor TR1 connected in series between a second input terminal 12 and a power supply terminal 14, and a negative resistance element ND1 and a transistor The common connection point of TR1 is connected to the output terminal 13, and the gate of the transistor TR1 is connected to the first input terminal 11. Note that the transistor TR1 can be replaced with a bipolar transistor. In this case, the first input terminal 11 is connected to the base.
[0013]
The characteristics of the multi-stable circuit 10 will be described with reference to the load curve diagram shown in FIG. X is a load curve of the resonant tunnel diode ND1. Y is a voltage-current curve of the transistor TR1, and transitions upward when the input voltage Vin1 increases. FIG. 5 shows a case where Vin2 = V2. When Vin2 = V1, the load curve X transitions to the left, and there is only one stable state.
[0014]
When Vin2 = V2, when Vin1 <Vt, the output signal Vout of the multi-stable circuit 10 can take two values of Vout = VL and VH, but when Vin1> Vt, the output signal Vout is VL regardless of Vin2. Take only. Therefore, the input / output characteristics of this circuit are as shown in FIG. 6, which is the same as FIG. 2B. When Vin2 is set to a value (V1) sufficiently close to 0, the multi-stable circuit 10 has only one stable state, and Vout = VL. Further, when Vin2 is raised from V1 to V2, if Vin1 <Vt, the output voltage Vout transitions to VH. Therefore, the circuit shown in FIG.
[0015]
In this multistable circuit 10, as shown in FIG. 7, another field effect transistor TR2 is connected between the negative resistance element ND1 and the power supply terminal 15, and the gate of the transistor TR2 is connected to the second input terminal. 12, the same operation and effect can be obtained even if it is configured as a multistable circuit 10 'in which the input voltage Vin2 is supplied as Vin2' by the transistor TR2. Here, the transistors TR1 and TR2 can be replaced with bipolar transistors. In this case, the first input terminal 11 and the second input terminal 12 are connected to the base.
[0016]
【The invention's effect】
As described above, according to the present invention, the function of the phase comparison circuit can be realized with a very small number of elements such as two or three. Further, since there is no constant current source, current consumption can be reduced.
[Brief description of the drawings]
FIG. 1 is a block diagram of a phase comparison circuit according to an embodiment of the present invention.
2A and 2B are characteristic diagrams of the operation of the phase comparison circuit of FIG. 1, where FIG. 2A is a characteristic diagram when Vin2 = V1, and FIG. 2B is a characteristic diagram when Vin2 = V2.
FIG. 3 is an operation waveform diagram of the phase comparison circuit of FIG. 1;
FIG. 4 is a specific circuit diagram of a phase comparison circuit.
FIG. 5 is a load curve diagram of the phase comparison circuit of FIG. 4;
FIG. 6 is a characteristic diagram of the operation of the phase comparison circuit of FIG. 4;
FIG. 7 is another specific circuit diagram of the phase comparison circuit.
FIG. 8 is a circuit diagram of a conventional phase comparison circuit.
9 is an operation waveform diagram of the phase comparison circuit of FIG. 8;
[Explanation of symbols]
10: multi-stable circuit, 11: first input terminal, 12: second input terminal, 13: output terminal, 14: power terminal, 15: power terminal

Claims (3)

In a phase comparison circuit that receives two signals and extracts a signal corresponding to the phase difference,
A first input terminal, a second input terminal, and an output terminal;
When the signal at the second input terminal is at a first value, one of a plurality of stable states is exhibited according to the relationship between the signal at the first input terminal and a threshold value, and Outputting a signal having a value corresponding to one stable state to the output terminal;
When the second input signal has the second value, the second input signal exhibits a specific one of the plurality of stable states irrespective of the signal of the first input terminal. A phase comparison circuit for outputting a signal having a value corresponding to one stable state to the output terminal. The phase comparison circuit according to claim 1,
It comprises a transistor connected between the output terminal and the power supply terminal, and a negative resistance element connected between the output terminal and the second input terminal. A phase comparison circuit to which an input terminal is connected. The phase comparison circuit according to claim 1,
A first transistor connected between the output terminal and a first power supply terminal, a negative resistance element having one end connected to the output terminal, the other end of the negative resistance element and a second power supply terminal; And the second input terminal is connected to the gate or base of the first transistor, and the second input terminal is connected to the gate or base of the second transistor. A phase comparison circuit characterized by being connected.

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