JPH04253207A - Switching type voltage controlled loop - Google Patents

Abstract

PURPOSE:To make a circuit simple and low-priced by making circuits to control voltages common in the case of requiring the plural pairs of voltage control loops having various response time or the like and to smoothly change an objective output by smoothly switching the voltage for control inputted to the circuits to control the voltages. CONSTITUTION:The voltage controlled loop is provided with a circut 1 which is controlled with the inputted voltage to apply the objective output while being controlled by the input voltage, plural control voltage generators 2a-2n outputting the control voltage while comparing specified inputs with the objective outputs, and switching circuit 6 inputting the plural control voltages, to select/switch those control voltages and to output them as the voltages for controlling the circuits to control the voltages through a low-pass filter 5 having a time constant decided in advance.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voltage control loop of a voltage-controlled circuit which inputs a plurality of control voltages in a switched manner and outputs a desired output.

0002

2. Description of the Related Art A conventional switching type voltage control loop of this type will be explained with reference to a block diagram shown in FIG. 1(
1a to 1n) are voltage controlled circuits that are controlled by the input control voltage and output a target output; 2 (2a to 2n);
is a control voltage generator that compares a specific input (A to N, N is a positive integer) with the target output from the voltage controlled circuit 1 and outputs a control voltage. Conventionally, a plurality of sets (n sets of a to n, n is a positive integer) of the voltage controlled circuit 1 and the control voltage generator 2 are prepared, and a switch control circuit 4 receives command input from the outside. One of a plurality of (n) target outputs is selected as the final target output by a switch 3 of an N-input circuit controlled by .

Here, the voltage controlled circuit 1 may be, for example, a voltage controlled oscillator, and the controlled voltage generator 2 may be a phase synchronized oscillation circuit, which is a wave detector. . At this time, the control voltage generator 2 inputs the target output of the voltage controlled circuit 1 as a reference signal, compares the phase with the input A, that is, a signal with almost the same frequency as the reference signal (detects), and controls the comparison output. Output as voltage A. The voltage controlled circuit 1 outputs a target output whose frequency is controlled by the control voltage A. At this time,
Naturally, the response times of the N sets of voltage control loops differ depending on the control amount and the like.

0004

[Problems to be Solved by the Invention] In the conventional voltage control loop described above, when multiple sets of voltage control loops with different response times, etc. are required, it is necessary to install as many voltage controlled circuits and control voltage generators as required. It is necessary to prepare a circuit, which has the disadvantage that the circuit has a huge configuration and is expensive.

[0005]

[Means for Solving the Problems] The switching voltage control loop of the present invention includes a voltage controlled circuit that is controlled by an input voltage and outputs a target output, and a control voltage that compares a specific input with the target output. a plurality of control voltage generators that output the voltage, and a low-pass filter that inputs the control voltages from the plurality of control voltage generators, selects and switches the plurality of control voltages, and has a predetermined time constant. and a switching circuit that outputs a control voltage for the voltage controlled circuit.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram of one embodiment of the present invention.

This voltage control loop includes a voltage controlled circuit 1 which is controlled by an input voltage and outputs a target output.
and a plurality of (N in this case, A to N) controls that compare specific inputs (A to N) and the target output output from the voltage controlled circuit 1 and output control voltages (A to N). A voltage generator 2 (2a to 2n), a switch 3 that inputs a plurality of control voltages from the control voltage generator 2, and a switch 3 that inputs a control voltage selected by the switch 3 and sets the control voltage to a predetermined voltage. It is comprised of a low-pass filter 5 that outputs a voltage with a time constant to the voltage-controlled circuit 1, and a switch control circuit 4 that controls switching of the switch 3 of the N-input circuit by inputting a command from the outside.

Now, when the switch 3 selects the switch A, the voltage controlled circuit 1 receives the control voltage A from the input A.
It is controlled by the voltage from Next, when the changeover device 3 is switched to switch B, the voltage input to the voltage controlled circuit 1 is changed from the voltage generated by the control voltage A to the voltage generated by the control voltage B. It switches according to a time constant of 5. After that, control voltage B due to input B
will be controlled by. Therefore, the time constant of the low-pass filter 5 is changed to the voltage-controlled circuit 1 and the plurality of control voltage generation circuits 2 (excluding the switching circuit 6 composed of the switching device 3 and the low-pass filter 5). If the time constant is set longer than the maximum time constant of multiple sets (n sets) of voltage control loops consisting of combinations of voltage control loops 2a to 2n), the gap in the voltage input to the voltage controlled circuit 1 when switching the voltage control loops can be reduced. It is possible to eliminate this problem and achieve a smooth transition to the desired output. The same applies to the operations of other voltage control loops.

It goes without saying that the actual circuits of the voltage controlled circuit 1 and the control voltage generator 2 may be phase synchronized oscillation circuits as described in the conventional example.

[0011]

Effects of the Invention As explained above, when multiple sets of voltage control loops with different response times, etc. are required, the present invention can simplify the circuit configuration and reduce the cost by making the voltage controlled circuit common. This has the effect of Further, by smoothly switching the control voltage input to the voltage controlled circuit, the target output can be smoothly changed.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of one embodiment of the present invention.

FIG. 2 is a block diagram of a conventional example.

[Explanation of symbols]

1 (1a to 1n) Voltage controlled circuit 2 (2a to 2
n) Control voltage generator 3 Switcher 4 Switch control circuit 5 Low-pass filter 6 Switching circuit

Claims (2)

[Claims] 1. A voltage controlled circuit that is controlled by an input voltage and outputs a target output, a plurality of control voltage generators that compare a specific input with the target output and output a control voltage, and a plurality of control voltage generators that output a control voltage by comparing a specific input with the target output. a switching circuit that inputs a control voltage from a control voltage generator, selects and switches the plurality of control voltages, and outputs it as a control voltage for the voltage-controlled circuit through a low-pass filter having a predetermined time constant; A switched voltage control loop comprising: 2. The time constant is set to be longer than the maximum time constant of a plurality of voltage control loops including the voltage controlled circuit excluding the switching circuit and the control voltage generating circuit. The switched voltage control loop of claim 1.