JP2003169470A - Power supply unit and feeding system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact and low-cost power supply unit that has a voltage detection line for detecting a voltage at the input section of each load board, can determine and control an optimum DC power supply output (Vo) based on each voltage detection value, and to provide a feeding system. <P>SOLUTION: The power supply unit for supplying a common supply voltage to a plurality of load boards comprises a plurality of remote detection means for detecting voltages at input sections in a plurality of load apparatuses, an output means for determining and outputting the output voltage of the power supply unit according to a plurality of detection values obtained by the remote detection means, and a constant voltage control means for carrying out constant voltage control to the output means. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for an electronic apparatus represented by an image forming apparatus such as a copying machine / printer, in which one power supply unit supplies power supply voltage to a plurality of loads. The present invention relates to a power supply device and a power supply system that perform mold power supply.

[0002]

2. Description of the Related Art In recent years, image forming apparatuses such as copying machines / printers have been digitized and networked. These devices are often composed of a plurality of boards such as a board for controlling image processing, a board for controlling image formation, and a board for controlling communication. Further, due to advances in semiconductor microfabrication technology, high integration of digital elements such as CPU / ASIC is progressing, and power supply voltage is further decreasing. As the voltage is becoming lower, the absolute voltage accuracy requirement (± 50 mV, etc.) of the power supply is becoming stricter.

Conventionally, as shown in FIG. 5, there was no problem in simply connecting in parallel to a plurality of load boards (load 1 to load 4) with a bundled wire, but in recent years the trend of low voltage Below, the voltage drop due to the bundling became problematic.

(1) Therefore, as shown in FIG.
In order to reduce the impedance of the bundled wire / connector, etc. indicated by Z4, the bundled wire is made thicker and shorter to prevent voltage drop.

(2) Further, as shown in FIG. 6, the voltage of the input portion of the load board load 1 for which the highest voltage accuracy is required is detected, and the output voltage of the DC power supply is adjusted so that the voltage becomes constant. Methods using remote sense technology to control are also practiced.

(3) Furthermore, as shown in FIG. 7, a method is also used in which an independent DC / DC converter is arranged on each load board or on its input section and the power supply voltage is independently controlled for each board. Has been.

[0007]

However, in the above-mentioned conventional example, in the above-mentioned (1), there are great restrictions on the electrical equipment of each load board, the cost of wire bundle processing / wiring increases, and There are drawbacks such as an increase in area.

In the above (2), only the input voltage of the load 1 is guaranteed, but the other loads (load 2 to load 4) are not guaranteed at all.

The above item (3) is disadvantageous in cost and mounting area.

The present invention has been made in view of the above circumstances and is provided with a voltage detection line for detecting the voltage of the input section of each load board, and based on each voltage detection value,
Small size that can determine and control the optimum DC power output (Vo)
An object is to provide a low-cost power supply device and power supply system.

[0011]

The present invention can solve the above-mentioned problems by providing the following constitutions.

(1) A power supply device for supplying a common power supply voltage to a plurality of load boards, which is obtained by a plurality of remote detecting means for detecting a voltage of an input portion of the plurality of load devices and the remote detecting means. A power supply device comprising: output means for determining and outputting the output voltage of the power supply device based on a plurality of detected values; and constant voltage control means for performing constant voltage control on the output means.

(2) In the power supply device described in (1) above, an average value of the plurality of detected values is calculated, and the calculated value is
A power supply device, characterized in that the output voltage of the power supply device is determined so as to be a predetermined value.

(3) In the power supply device described in (1) above, the sum of squares (= variance σ) of the differences between the plurality of detected values and the predetermined target values is calculated, and the calculated values are
A power supply device characterized in that the output voltage of the power supply device is determined so as to be equal to or less than a predetermined value.

(4) In the power supply device described in the above item (1), the sum of squares of differences between the plurality of detected values and predetermined target values multiplied by a predetermined weighting coefficient is calculated as = Weighted variance σ ') is calculated, and the output voltage of the power supply device is determined such that the calculated value is equal to or less than a predetermined value.

(5) A power supply system for supplying a common power supply voltage to a plurality of load boards, wherein a plurality of remote detection means for detecting a voltage of an input portion of a plurality of load devices and a remote detection means are provided. The output voltage of the power supply device is determined from a plurality of detected values and output, and a constant voltage control means for performing a constant voltage control on the output means, and an average value of the plurality of detected values. And the calculated value is
Determine the output voltage of the power supply device so as to be a predetermined value, or calculate the sum of squares (= variance σ) of the difference between each of the plurality of detected values and a predetermined target value, The output voltage of the power supply device is determined so that the calculated value is less than or equal to a predetermined value, or the difference between the plurality of detection values and the predetermined target value is squared. The sum of the multiplied weighting factors ((=
A power supply system, characterized in that a weighted variance σ ′) is calculated, and the output voltage of the power supply device is determined so that the calculated value is equal to or less than a predetermined value.

That is, as shown in FIG. 1, the voltages V1 to V4 at the input portions of the respective load boards (load 1 to load 4) are detected, and the optimum DC power supply output voltage Vo is determined from the detected values to determine the constant voltage. Control.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a power supply device and a power feeding system of the present invention will be described below.

FIG. 1 is a block diagram showing the overall configuration of a power supply device according to the first embodiment, FIG. 2 is a block diagram showing a detailed configuration example of the power supply device according to the first embodiment, and FIG.
4 is a flowchart (main routine) showing the operation of the power supply system in FIG. 4, FIG. 4 is a flowchart showing the operation of the power supply system in the first embodiment (subroutine 1), and FIG. 5 is a block diagram showing a configuration example of the power supply device in the first conventional example. FIG. 6 is a block diagram showing a configuration example of a power supply device in Conventional Example 2, FIG. 7 is a block diagram showing a configuration example of a power supply device in Conventional Example 3, and FIG. 8 is an operation of the power supply system in Example 2. 9 is a flowchart (subroutine) showing the operation of the power supply system in the second embodiment.

As a method for determining the optimum DC power supply output voltage Vo, (1) the average value of V1 and V2 is set to a predetermined value. (2) Minimize the variation from the power supply voltage allowable center value of each load board (dispersion minimization). (3) When the voltage accuracy requirements of each load board are different, weighting is performed according to the required accuracy for each load board,
A method such as minimizing the variance from the power supply voltage allowable center value (minimization of weighted variance) can be considered.

(Embodiment 1) In FIG. 2, T1 is a switching power supply transformer, which is composed of a primary winding N11 and a secondary winding N21. The commercial power source Vin (AC) is rectified by the diode bridge DB1 and smoothed by the smoothing capacitor C1 to obtain the DC voltage Vin (DC). The DC voltage Vin (DC) charged in the smoothing capacitor C1 is high-frequency switched by the field effect transistor (FET) Q1 and applied to the transformer primary winding N11.
Then, a pulse voltage synchronized with the high frequency pulse applied to the N11 winding by the field effect transistor Q1 is generated in the transformer secondary winding N21. This is rectified and smoothed by the diodes D11 and D12, the choke coil L11, and the smoothing capacitor C11 to obtain the DC voltage Vo.

The selection means 51 is a DSP (Digital Signal).
Vo) in response to the detection point selection signal from the processor 55.
Alternatively, one of the voltage detection lines 1 to 4 described below is selected and connected to the filter circuit 52. The output of the filter circuit 52 is converted into digital data by the A / D converter 54 through the sample and hold circuit 53, and the DSP 5
Input to 5.

The operation algorithm in the DSP 55 will be described later.

By controlling the ON / OFF time ratio (duty) of switching of the field effect transistor (FET) Q1 by using the transistor Q21 and the transformer T21 by the PWM signal generated by the DSP 55,
A constant voltage control of the Vo to a predetermined voltage is realized.

Next, the voltage detection lines 1 to 4 will be described with reference to FIG.

In FIG. 1, the DC power supply represents the switching power supply described in FIG.

The output of the DC power source uses a wiring material or the like to represent four printed board units (CPU 1 to load 4).
Board).

In the figure, Z0 to Z4 represent line impedances due to wirings, connecting connectors, etc. In particular, Z0 is a common impedance, and Z1 is a line impedance resulting only from wiring to the load 1.
The same applies to Z2 to Z4.

The voltage V1 at the power source input point of the load 1 is taken into the DC power source through the voltage detection line 1, and the selection means 51 of FIG.
Connect to. Similarly, for the loads 2 to 4, the voltages V2 to V4 at the power source input point are converted to DC by the voltage detection lines 2 to 4.
It is taken into the power source and connected to the selection means 51 of FIG.

Next, an example of the operation algorithm in the DSP 55 will be described with reference to FIG.

(1) The control lower limit voltage Ref1 and the upper limit voltage Re of the output voltage Vo of the DC power supply are set so that the average value D of the voltage of each load board input section becomes RefA <D <RefB.
Determine f2.

First, in step S301, the counter is reset (X = 0, Y = 0, Z = 0), and step S302.
Starts counting up (Z = Z + 1) with step S
If the counter Z is larger than the predetermined value Z0 in 303, the process proceeds to step S304 and the subroutine 1 (determination of Ref1 and Ref2) is performed.

The operation of the subroutine 1 will be described with reference to FIG.

The voltage detecting line 1 to the voltage detecting line 4 are sequentially selected by the selecting means 51, and the voltage V1 of each load board input portion is selected.
~ V4 is a filter circuit 52, a sample and hold circuit 5
3 through 3, it is taken into the A / D converter 54 and converted into digital data D1 to D4. D = 1/4 * (D1 + D2
+ D3 + D4) is calculated to obtain the average value D of each load board input voltage.

If RefA ≧ D, Ref1 = Ref1
The control lower limit voltage Ref1 of the output voltage Vo1 of the DC power supply is counted up as +1 and Ref2 = Ref2 + 1.
Is the control upper limit voltage Re of the output voltage Vo1 of the DC power supply.
Count up f2.

If D ≧ RefB, Ref1 = Ref1
As -1, the control lower limit voltage Ref1 of the output voltage Vo1 of the DC power source is counted down, and Ref2 = Ref2-1.
Is the control upper limit voltage Re of the output voltage Vo1 of the DC power supply.
Count down f2.

If RefA <D <RefB, Ref1
= Ref1 holds the control lower limit voltage Ref1 of the output voltage Vo1 of the DC power supply, and Ref2 = Ref2 holds
The control upper limit voltage Ref2 of the output voltage Vo1 of the DC power supply is held. Control voltage lower limit Ref1 and upper limit Ref based on the above
By repeating the process of determining 2, RefA <D
The control lower limit voltage Ref1 and the upper limit voltage Ref2 of the output voltage Vo of the DC power supply are determined so that <RefB.

(2) And Ref1 <Vo1 <Ref
2, the field effect transistor (FET)
Q1 switching on time Ton, off time Toff
To decide.

On the other hand, in step S303, the counter Z
Is smaller than a predetermined value Z0, the selecting means 51 selects the DC power output voltage Vo1 (step S306). The digital data D0 is taken into the A / D converter 54 through the filter circuit 52 and the sample and hold circuit 53 (step S307).
(Step S308).

D0 and Ref1 are compared (step S30
9) If D0 ≦ Ref1, counter X is incremented (step S310). If the value of the counter X is less than or equal to a predetermined value X0 (step S31
1), D0 is taken in again. If the value of the counter X is larger than the predetermined value Xo, Ton is incremented by 1 and Toff is decremented by 1 (step S312).

If D0> Ref1 in step S309, D0 and Ref2 are compared in step S313. If D0 ≧ Ref2, the counter Y is incremented (step S314). If the value of the counter Y is less than or equal to a predetermined value Y0 (step S31
5) Take D0 again. If the value of the counter Y is larger than the predetermined value Y0, in step S316,
Count down one Ton and count up Toff one.

If Ref1 <D0 <Ref2, To
Hold n and Toff as they are.

P at Ton and Toff determined above
A WM pulse signal is generated (step S317), and thereby the on / off time ratio (duty) of switching of the field effect transistor (FET) Q1 is controlled by using Q21 and T21. V
Constant voltage control of o to a predetermined voltage.

With the above configuration, the average value D of the voltage of each load board input section is RefA <D <RefB.
Can be controlled so that

Example 2 Example 2 is shown in FIG.

In the second embodiment, the variation from the power supply voltage allowable center value of each load board is minimized (dispersion minimization).

The recommended voltage value of the input power source may differ depending on the CPU or ASIC. In that case, the DC power supply output voltage Vo should be set so that the following dispersion values σ are minimized by setting the recommended voltages of the load boards 1 to 4 as Vs1 to Vs4, instead of simply taking the average value. Is desirable.

Σ = (V1-Vs1) ² + (V2-Vs
2) ² + (V3-Vs3) ² + (V4-Vs4) ² Below, an algorithm example of the subroutine will be described (others are the same as in Example 1 and omitted).

The variance value σ of the voltage of each load board input section is
The control lower limit voltage R of the output voltage Vo of the DC power supply is set so that σ <RefC with respect to a predetermined value RefC.
ef1 and the upper limit voltage Ref2 are determined.

The operation of the subroutine will be described with reference to FIG.

The voltage detecting line 1 to the voltage detecting line 4 are sequentially selected by the selecting means 51, and the voltage V1 of each load board input portion is selected.
~ V2 is a filter circuit 52, a sample and hold circuit 5
3 through 3, it is taken into the A / D converter 54 and converted into digital data D1 to D4. The recommended voltage of each load board 1 to 4 is the digital expression value of Vs1 to Vs4 is Ds1 to Ds.
It is stored as 4.

Σ = (D1-Ds1) ² + (D2-Ds
^{2) 2 + (D3-Ds3} ) 2 + (D4-Ds4) 2 was calculated and compared with RefC.

(A) If σ ≦ RefC, Ref1 = R
The control lower limit voltage Ref1 of the output voltage Vo of the DC power supply is held as ef1, and the control upper limit voltage Ref2 of the output voltage Vo of the DC power supply is held as Ref2 = Ref2.

(B) If RefC <σ, the previous dispersion calculation value σ− is compared with the current dispersion calculation value σ (step S
804) (however, σ− = σ is set in the first time).

When σ ≦ σ−: Ref1 = Ref1 +
P, Ref2 = Ref2 + P, P = 1, σ− = σ (step S805) When σ> σ−: Ref1 = Ref1-P, Ref2 =
Ref2-P, P = -1, σ- = σ (step S80
6) (However, P = 0 at the first time).

The new Ref1, Re obtained as described above
By using f2, the process returns to the main loop, and the DC power supply voltage Vo1 is controlled to a constant voltage as in the first embodiment. Then again
At the appropriate timing, move to the above subroutine and execute Re
Reset f1 and Ref2. By repeating this,
Ref1 and Ref whose dispersion value σ satisfies σ ≦ RefC
2 can be set.

(Embodiment 3) Embodiment 3 is shown in FIG.

In the third embodiment, when the voltage accuracy requirement of each board is different, weighting is performed according to the required accuracy for each board so that the variance from the power supply voltage allowable center value is minimized (weighting). Variance minimization).

Depending on the CPU, ASIC, etc., the recommended voltage value of the input power supply may differ, and the allowable value of the voltage accuracy may also differ.

In that case, instead of simply taking the variance value σ described in the second embodiment, the recommended voltages of the load boards 1 to 4 are set to Vs1 to Vs4, and the voltage tolerance accuracy of each board is set to Q1 to Q4. , It is desirable to set the DC power supply output voltage Vo so that the following weighted dispersion value σ ′ is minimized.

Σ '= Q1 ² * (V1-Vs1) ² + Q2 ²
* (V2-Vs2) ² + Q3 ² * (V3-Vs3) ² + Q
4 ² * (V4-Vs4) ² Below is an example of the algorithm of the subroutine (others are the same as in Example 1 and will be omitted).

The weighted variance value σ ′ of the voltage of each load board input section is σ ′ with respect to a predetermined value RefC.
The control lower limit voltage Ref1 and the upper limit voltage Ref2 of the output voltage Vo of the DC power supply are determined so that <RefC is satisfied.

The operation of the subroutine will be described with reference to FIG.

The voltage detecting line 1 to the voltage detecting line 4 are sequentially selected by the selecting means 51, and the voltage V1 of each load board input portion is selected.
~ V2 is a filter circuit 52, a sample and hold circuit 5
3 through 3, it is taken into the A / D converter 54 and converted into digital data D1 to D4. The recommended voltage of each load board 1 to 4 is the digital expression value of Vs1 to Vs4 is Ds1 to Ds.
4, and the digital expression values of Q1 to Q4 are stored as q1 to q4.

Σ '= q1 ² * (D1-Ds1) ² + q2 <sup>2
* (D2-Ds2) 2 +</sup> q3 2 * (D3-Ds3) 2 + q
Calculate 4 ² * (D4-Ds4) ² and compare with RefC.

(A) If σ ′ ≦ RefC, Ref1 =
The control lower limit voltage Ref1 of the output voltage Vo of the DC power source is held as Ref1, and the DC is set as Ref2 = Ref2.
The control upper limit voltage Ref2 of the output voltage Vo of the power supply is held.

(B) If RefC <σ ′, the previous dispersion calculation value σ− ′ and the current dispersion calculation value σ ′ are compared (step S903) (however, at the first time, σ − ′ = σ ′).
And).

When σ ′ ≦ σ− ′: Ref1 = Ref1
+ P, Ref2 = Ref2 + P, P = 1, σ − ′ = σ ′
(Step S904) When σ ′> σ− ′: Ref1 = Ref1-P, Ref
2 = Ref2-P, P = −1, σ − ′ = σ ′ (step S905) (However, P = 0 at the first time).

The new Ref1, Re obtained as described above
By using f2, the process returns to the main loop, and the DC power supply voltage Vo1 is controlled to a constant voltage as in the first embodiment. Then again
At the appropriate timing, move to the above subroutine and execute Re
Reset f1 and Ref2. By repeating this,
Re with weighted variance σ ′ satisfying σ ′ ≦ RefC
f1 and Ref2 can be set.

A flow chart showing a subroutine,
4, FIG. 8, and FIG. 9, steps that represent the same operation are assigned the same reference numerals.

[0071]

As described above, the voltage detection line for detecting the voltage of the input portion of each load board is provided,
The optimum DC power output (V
It is possible to provide a small-sized and low-cost power supply device and power supply system capable of determining and controlling o).

[Brief description of drawings]

FIG. 1 is a block diagram showing an overall configuration of a power supply device according to a first embodiment.

FIG. 2 is a block diagram illustrating a detailed configuration example of a power supply device according to the first embodiment.

FIG. 3 is a flowchart (main routine) showing the operation of the power supply system in the first embodiment.

FIG. 4 is a flowchart showing the operation of the power feeding system in the first embodiment (subroutine 1).

FIG. 5 is a block diagram showing a configuration example of a power supply device in Conventional Example 1.

FIG. 6 is a block diagram showing a configuration example of a power supply device in Conventional Example 2.

FIG. 7 is a block diagram showing a configuration example of a power supply device in Conventional Example 3.

FIG. 8 is a flowchart (subroutine) showing the operation of the power supply system in the second embodiment.

FIG. 9 is a flowchart (subroutine) showing the operation of the power supply system in the second embodiment.

[Explanation of symbols]

Q1 Field effect transistor (FET) C1, C11 smoothing capacitors T1 switching power transformer D11 Rectifier diode D12 flywheel diode L11 choke coil N11 primary winding N21 secondary winding

Continued front page    F-term (reference) 5G065 AA08 FA01 GA04 HA04 JA01                       JA07 LA01                 5H730 AA12 AS01 BB23 BB57 CC01                       DD04 DD22 EE02 EE08 EE10                       EE61 FD01 FF09 FF18 FG05                       FG11 FG25

Claims (5)

[Claims] 1. A power supply device for supplying a common power supply voltage to a plurality of load boards, comprising: a plurality of remote detection means for detecting a voltage of an input portion of the plurality of load devices; and a plurality of remote detection means. From multiple detection values,
A power supply device comprising: an output unit that determines and outputs an output voltage of the power supply unit; and a constant voltage control unit that performs constant voltage control on the output unit. 2. The power supply device according to claim 1, wherein an average value of the plurality of detected values is calculated, and the output voltage of the power supply device is determined so that the calculated value becomes a predetermined value. Power supply device characterized by. 3. The power supply device according to claim 1, wherein a sum of squares (= dispersion σ) of differences between the plurality of detected values and respective predetermined target values is calculated, and the calculated values are predetermined. A power supply device, characterized in that the output voltage of the power supply device is determined so as to be equal to or less than a preset value. 4. The power supply device according to claim 1, wherein a sum of values obtained by multiplying a square of a difference between each of the plurality of detected values and a predetermined target value by a predetermined weighting coefficient (= weight). Power supply device, wherein the output voltage of the power supply device is determined so that the calculated dispersion σ ′) is equal to or less than a predetermined value. 5. A power supply system for supplying a common power supply voltage to a plurality of load boards, comprising: a plurality of remote detection means for detecting a voltage of an input part of a plurality of load devices; and a plurality of remote detection means. From multiple detection values,
An output unit that determines and outputs the output voltage of the power supply device and a constant voltage control unit that performs constant voltage control on the output unit are provided, and an average value of the plurality of detection values is calculated, and the calculated value is , Determine the output voltage of the power supply device so as to be a predetermined value, or calculate the sum of squares (= variance σ) of the differences between the plurality of detection values and the respective predetermined target values. , The output voltage of the power supply device is determined so that the calculated value is equal to or less than a predetermined value, or the square of the difference between the plurality of detection values and the predetermined target value is calculated in advance. A sum of values determined by multiplying a predetermined weighting coefficient is calculated (= weighted variance σ ′), and the output voltage of the power supply device is determined so that the calculated value is equal to or less than a predetermined value. Power supply system characterized by.