JPH0626358B2 - Power supply voltage control circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is used in a power supply circuit mounted in a communication device. In particular, it relates to a means for monitoring the power supply voltage supplied from the parent device to the child device by the child device, returning the monitoring result to the parent device, and controlling the output voltage supplied by the parent device to the child device.

〔Overview〕

According to the present invention, in a voltage control means of a power supply circuit mounted on a communication device having a relationship between a parent and a child, a result of detecting a change in voltage drop due to a line by the child device is returned to the parent device, and the child device is based on this information. By controlling the power supply voltage supplied to the device, an appropriate voltage can be given to the child device.

[Conventional technology]

In the conventional example, when power is supplied to each of the parent device 1 and the child device 20, as shown in FIG. 2, AC input powers 7 and 30 are supplied to the respective devices, and the ACDC power supply circuit 2 is supplied.
Then, the AC input power sources 7 and 30 are converted into DC output power sources 9 and 29 to be distributed in the apparatus. The output voltage value of the ACDC power supply circuit 2 is generally set to be semi-fixed. In addition, as shown in FIG.
A method of supplying the output power supply 9 via the DC power supply line 32 is also used.

That is, as a method of supplying power to the child device 20, 1) supply AC power to each of the parent device and the child device,
There are a method of internally having a power supply circuit for converting to a DC power supply and distributing the output within the device, and a method of 2) having a power supply circuit in the parent device and supplying the output to the child device.

However, in 1) above, depending on the installation location of the child device, AC
Power may not be supplied. Further, in order to reduce the cost of the device by simplifying or downsizing the power supply circuit of the child device, the method 2) of supplying DC power from the parent device to the child device has been increasingly used. As the method 2), as shown in FIG. 3, a method of providing a dedicated line for supplying DC power and a method of multiplexing DC power on the line for information transmitted between the parent and child devices are provided. There is a method of supplying in one form, that is, a method of sharing one line.

[Problems to be solved by the invention]

As described above, in the conventional example, when the parent apparatus supplies the DC power to the child apparatus, generally, the AC power is supplied to the parent apparatus by the DC power.
A power supply circuit for converting to a power supply is provided, and a small stabilized power supply circuit for stabilizing the voltage of the DC power supplied from the parent device is provided to the child device.

However, if the distance between the parent device and the child device is 100 to 200 m, there is a problem that the voltage value of the DC power supply supplied to the child device decreases due to the voltage drop due to the line length.
As a measure to solve this problem, there is a method of adding a voltage drop amount to the voltage value of the DC power source in advance in the parent device to increase the voltage value by the voltage drop amount. The slave device stabilizes the DC power supply voltage output at this higher level by the stabilizing power supply circuit and distributes it to the inside of the device.

However, if the distance between the parent device and the child device is long, the input voltage of the stabilized power supply circuit of the child device becomes an appropriate value due to the line voltage drop even if the parent device outputs a higher voltage. However, when the distance is short, the input power supply voltage of this stabilized power supply circuit becomes high, and the power difference between this input power and the input power of the stabilized power supply circuit is converted into heat loss, which reduces efficiency. . In addition, the heat generated by the heat loss raises the operating temperature of the components forming the power supply circuit, which leads to a decrease in reliability. In addition, a heat radiation mechanism is required, which causes an increase in the price of the device and hinders miniaturization.

The present invention eliminates such drawbacks, and an object of the present invention is to provide a power supply voltage control circuit capable of giving an appropriate power supply voltage to a device without being affected by the line length.

[Means for solving problems]

The present invention includes a parent device having a power supply circuit for converting a given AC voltage into a DC voltage, and a child device connected to the parent device via a transmission line. In a power supply voltage control circuit included in a system that includes a stabilizing circuit that adjusts a given DC voltage to generate a DC voltage of a predetermined value, the power supply circuit has a voltage value suitable for supplying to the parent device. A voltage detecting circuit having means for generating a first direct current voltage and a second direct current voltage to be applied to the stabilizing circuit, wherein the slave device measures the voltage value of the direct current voltage applied to the stabilizing circuit; A first data processing means for generating a control signal relating to the voltage value measured by the voltage detection circuit and the voltage value of the DC voltage generated by the stabilizing circuit is provided, and the parent device is provided with the first data processing means. This control transferred The adjustment of the value of the predetermined portion of the voltage value of the second DC voltage is tried based on the signal, and the trial is repeatedly executed at the predetermined cycle until the value of the control signal that fluctuates by the trial reaches the predetermined value. A second data processing means is provided. That is, in the parent device, ACDC power supply circuit means capable of controlling one of two or more secondary output voltages from the outside of the power supply circuit, and ACDC power supply circuit having a secondary output voltage fixed part and a variable part. And a microprocessor means for transmitting and receiving information for controlling the power supply voltage between the parent device and the child device, a microprocessor for controlling the operating functions of the parent device and the child device, and a microprocessor for voltage control. A / D conversion circuit means for converting a digital control signal into an analog control signal, information for controlling a power supply voltage between a parent device and a child device, analog or digital communication information, and a power supply supplied to the child device are multiplexed. And demultiplexing circuit means for performing demultiplexing, and multiple signal line means for transmitting the multiplexed information and power source by a single line. DC performing the demultiplexing circuit means for multiplexing and separation of information and power supply, and a detection and monitoring of the power supply voltage supplied from the parent device
The outputs of the voltage detection circuit means, the stabilized power supply circuit means for making the power supply voltage that fluctuates depending on the multiple signal line length constant and distributing it to the device, the outputs of the DC power supply detection circuit and the stabilized power supply circuit are analyzed, and the results are analyzed. It has a microprocessor means for transferring to the parent device and a microprocessor for controlling the operation function of the child device, supplies power from the parent device to the child device, and causes the voltage fluctuation caused by the length of the multiple signal line which is a single line to the child device. The device performs monitoring and detection, and the result is fed back to the power supply circuit of the parent device using the function of asynchronous communication of the microprocessor, and the power supply voltage supplied to the child device is controlled by controlling the variable part of the power supply voltage. Voltage control can be performed so that heat loss is small and efficiency is high.

In addition, the result of monitoring and detection by the DC power source detection circuit is directly processed by the demultiplexing circuit means without being processed by the microprocessor means, and is transmitted to the parent device by the demultiplexing circuit means. The result may be separated and the power supply voltage on the secondary side of the ACDC power supply circuit means may be controlled by this result.

In addition, the information for controlling the power supply voltage is transmitted by the multiple signal line means between the parent device and the child device, but the transmission path from the parent device to the child device and the transmission path from the child device to the parent device are One wave by the division method may be commonly used.

In addition, the transmission path from the parent device to the child device and the transmission path from the child device to the parent device may be used exclusively for each of two waves by the frequency division method.

In addition, the power supply voltage supplied from the parent device to the child device is monitored and detected by the child device, and the result is fed back to the power circuit of the parent device to control the variable part of the power circuit. When turned on, it outputs the fixed part, which is the lowest power supply voltage that guarantees the operating function of the microprocessor of the child device due to the voltage fluctuation due to the multiple signal line length among the output voltage of the power supply circuit, and then outputs the fixed part There may be provided means for controlling the variable part by initial control by the microprocessor and thereafter performing voltage control at a predetermined cycle.

Also, analog or digital communication information and the power supply to be supplied to the child device are multiplexed by the demultiplexing circuit means and transmitted by a single line. Good.

[Action]

When supplying DC power to devices connected by a transmission line,
Converting the AC voltage drawn into the parent device to generate two DC voltages, giving one to the device itself, treating the other DC voltage as two parts, fixing one part and connecting one The data related to the voltage drop generated by the transmission line is received from the connected child device, and the voltage of the other part is adjusted based on this data and supplied to the child device.

〔Example〕

 An embodiment of the present invention will be described below with reference to FIG.

First, the configuration of this embodiment will be described with reference to FIG. A parent device 1 having an ACDC power supply circuit 2 which is a power supply circuit for converting a given AC voltage into a DC voltage, and a child device 20 connected to the parent device 1 via a multiple signal line 14 are provided. The device 20 is included in a system including a stabilized power supply circuit 23 that is a stabilizing circuit that adjusts the DC voltage applied from the multiplex signal line 14 to generate a DC voltage having a predetermined value, and the power supply circuit is The slave device 20 has means for generating a first DC voltage having a voltage value suitable for supplying to the parent device 1 and a second DC voltage applied to the stabilizing circuit, and the child device 20 is supplied with the DC voltage to the stabilizing circuit. A DC power supply detection circuit 22 which is a voltage detection circuit for measuring the voltage value of the control circuit, and a control signal for generating a control signal relating to the voltage value measured by the voltage detection circuit and the voltage value of the DC voltage generated by the stabilization circuit. Microp that is one data processing means A processor 24 is provided, and an attempt is made to adjust the value of a predetermined portion of the voltage value of the second DC voltage to the parent device 1 based on the control signal transferred from the first data processing means. The microprocessor 4 which is the second data processing means for repeatedly executing this trial at a predetermined cycle until the value of the control signal to be controlled reaches a predetermined value.
To provide.

Next, the operation of this embodiment will be described. An AC input power supply 7 is externally supplied to the parent device 1 to the ACDC power supply circuit 2. This ACDC power supply circuit 2 has two or more kinds of DC power supply voltage output terminals, and the DC output power supply 8 therein is a child device.
The DC output power source 9 is supplied to the signal processing circuit 3 for processing analog and digital signals. In particular,
As shown in FIG. 5, the output voltage of the DC output power source 8 includes a voltage fixing unit 50 and a voltage varying unit 51, and the DC voltage of the child device 20.
It is determined by the voltage value of the output power supply 29 and the voltage drop value caused by the line length of the multiple signal line 14. The DC output power source 8 is multiplexed by the demultiplexing circuit 6 with the analog digital signal 11 in the signal processing circuit 3 and the control signal 10 for controlling the operation function of the child device by the frequency division method as shown in FIG. And is supplied to the multiplex signal line 14. On the other hand, the child device 20 is a demultiplexing circuit having the same function as the demultiplexing circuit 6.
21 with analog digital signal 27, control signal 26, DC
Separated from the input power supply 25. This DC input power supply 25 is DC
It is supplied to the power supply detection circuit 22 and the stabilized power supply circuit 23. D
The C power detection circuit 22 is a DC input power supplied to the slave device 20.
25 voltage values are monitored and detected. The result is output to the microprocessor 24 as a DC voltage detection signal 28.
The DC power supply 29, which is the output of the stabilized power supply circuit 23, keeps the fluctuating DC input power supply 25 constant at a value required in the device, and distributes it to the device as the DC output power supply 29. The output of the DC power supply detection circuit 22 and the output of the stabilized power supply circuit 23 are output to the microprocessor 24 as analog signals. The microprocessor 24 analyzes these analog signals, converts them into control signals 26, and outputs them to the demultiplexing circuit 21. The demultiplexing circuit 21 multiplexes the analog digital signal 27 and outputs the multiplexed signal to the multiplexed signal line 14.

On the other hand, the parent device 1 separates the control signal 26 multiplexed on the multiplex signal line 14 by the demultiplexing circuit 6 and outputs it as the control signal 10 to the microprocessor 4. Control signal 10 and control signal 26
Includes information for controlling the voltage value of the DC input power supply 25 and information for controlling the operation function of the child device 20. When the microprocessor 4 analyzes the control signal 10 and confirms that no problem occurs even if the voltage is varied, the digital DC voltage control signal is converted into a DA conversion circuit so that the voltage value of the DC input power supply 25 becomes an optimum value. Output to 5. The DA conversion circuit 5 converts it into an analog voltage control signal 13 and outputs it to the ACDC power supply circuit 2. The ACDC power supply circuit 2 uses this DC voltage control signal
The voltage variable part of the DC output power source 8 is controlled by 13.

Next, control of the power supply voltage by the microprocessor will be described with reference to FIGS. 1 and 5. As shown in FIG. 5, the DC output power supply 8 which is the output of the ACDC power supply circuit 2 is composed of a voltage fixing unit 50 and a voltage changing unit 51. When the parent device 1 is powered on (state S1), the DC output power supply 8 of the ACDC power supply circuit 2 outputs the voltage value of the voltage fixing unit 50. At the same time, the DC output power source 9 is output, whereby the microprocessor 4 operates and outputs the initial control information to the DA conversion circuit 5 (state S2). This is the voltage variable section
Set the center value of the range of 51. Next, the child device 20 detects the voltage of the DC input power supply 25 by the DC power supply detection circuit 22 (state S3), and transfers the result to the microprocessor 4 of the parent device 1 using the start-stop synchronization communication means of the microprocessor 24. To be done. The microprocessor 4 judges whether the voltage value of the DC input power supply 25 is high or low, and outputs a DC voltage control signal 12 to the DA conversion circuit 5 so that the voltage value becomes an appropriate value, to perform voltage control (state S5). At this time, when the line length between the parent device 1 and the child device 20 is long, the voltage variable unit 51 is controlled in the direction of the maximum voltage value, and when the line length is short, it is controlled in the direction of the minimum voltage value. To do. After that, the voltage is detected by the DC power supply detection circuit 22 in a predetermined cycle (state S3), and the result is the parent device 1
And the voltage control is repeatedly executed (state S
4) The output of the ACDC power supply circuit 2 of the parent device 1 is controlled so that the DC output voltage 29 becomes a predetermined value.

〔The invention's effect〕

As described above, according to the present invention, the change in voltage drop due to the length of the line for supplying power is detected by the child device, the result is returned to the parent device, and the parent device supplies the child device based on this result. The power supply voltage is controlled so that 1) the power consumption of the power supply circuit installed in the parent device can be reduced.
The efficiency is improved, and 2) it is no longer necessary to set the voltage in consideration of the voltage drop due to the voltage drop caused by the length of the line length between devices.
The equipment installation cost can be reduced, 3) the power supply voltage input to the slave device can be set to an appropriate value, heat loss can be reduced, efficiency can be improved, and the heat dissipation function that radiates heat can be simplified and downsized can be realized. 4) Because the operating temperature of the components that make up the power supply circuit is low,
The reliability can be expected to improve, and there is a synergistic effect that the device price can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of the embodiment of the present invention. 2 and 3 are block configuration diagrams showing a configuration of a conventional example. FIG. 4 is a diagram showing a multiplexed state of a plurality of signals by the frequency division method. FIG. 5 is a time chart diagram showing the operation of the embodiment of the present invention. 1 ... Parent device, 2 ... AC DC power supply circuit, 3 ... Signal processing circuit, 4,24 ... Microprocessor, 5 ... DA conversion circuit, 6,21 ... Demultiplexing circuit, 7,30 ... AC Input power supply, 8, 9, 29 ... DC output power supply, 10, 26 ... Control signal, 11, 27 ... Analog / digital signal, 12, 13 ... D
C voltage control signal, 14 ... Multiple signal line, 20 ... Child device,
22 …… DC power supply detection circuit, 23 …… Stabilized power supply circuit, 25,
33 …… DC input power supply, 28 …… DC voltage detection signal, 32 ……
DC power supply line, 40 ... DC power supply, 41 ... Modulated control signal, 41 '... Modulated control signal (when using two waves), 42 ... Modulated analog digital signal, 50 ...
… Voltage fixed part, 51 …… Voltage variable part.

Claims (1)

[Claims] 1. A parent device having a power supply circuit for converting a given AC voltage into a DC voltage, and a child device connected to the parent device via a transmission line. The child device is provided with the transmission line. In a power supply voltage control circuit included in a system that includes a stabilizing circuit that adjusts the DC voltage given by the device to generate a DC voltage of a predetermined value, the power supply circuit is a voltage value suitable for supplying to the parent device. A first DC voltage and means for generating a second DC voltage to be applied to the stabilizing circuit, the slave device, a voltage detection circuit for measuring the voltage value of the DC voltage applied to the stabilizing circuit, First data processing means for generating a control signal for voltage value control including a voltage value measured by the voltage detection circuit and a voltage value of the DC voltage generated by the stabilizing circuit, and a multiplexing circuit for the control signal. To the parent device via Means for adjusting the value of a predetermined portion of the voltage value of the second DC voltage to the parent device based on the control signal transferred from the first data processing means, and 2. A power supply voltage control circuit, comprising: second data processing means for repeatedly executing this trial at a predetermined cycle until the value of the fluctuating control signal reaches a predetermined value.