JPH0538141A - Power supply device generating plural secondary power supplies - Google Patents

Abstract

PURPOSE:To stabilize simultaneously all secondary supply voltages respectively to set voltages by setting resistor voltage division circuits for signal and control so that their voltage values are equalized in the case the secondary supply voltage are at the setting voltage. CONSTITUTION:Resistor voltage division circuits R110, R100 and R120 for signal and resistor voltage division circuits R11, R12, R21 and R22 for control are respectively provided to secondary power supply paths L1 and L2 and, at the same time, when the secondary supply voltage +V1 and +V2 are in a state of setting voltage, terminal voltage values Vs1 and Vs2 of a signal generating element 41 are the same, and driving voltage values Vd1 and Vd2 of a control element 42 are so constituted that they are the same. Secondary supply voltage having the largest fluctuating width is so controlled by voltage signal generating circuits 41 and 42 provided to the secondary supply voltage side as a common circuit and one voltage control circuit 30 provided to primay voltage side that it is setting voltage, and any of the secondary supply voltages are stabilized simultaneously.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device for generating a plurality of secondary power supplies from a common primary power supply.

[0002]

2. Description of the Related Art FIG. 3 shows a general configuration of a power supply device for generating a plurality of secondary power supplies from a common primary power supply. In the figure, a primary power source is composed of a filter circuit 10 and a rectifier circuit 20 including a rectifier 21 and a smoothing capacitor 22, and this primary power source is a voltage control circuit 30 (power MOS 3
3, PWM control IC 34, photocoupler light receiver 35), and is connected to the primary winding (control winding 31, base winding 32) of the transformer Tr.

On the other hand, the secondary power source is a first secondary power source system path L1 drawn from the secondary winding CL1 of the transformer Tr, which is separately wound, and a second secondary power source system drawn from the secondary winding CL2. There are two (a plurality of) roads L2.

A resistor R11 is provided in the first secondary power supply path L1.
0, a signal generating element (photocoupler light emitter) 41, and a control element (shunt regulator) 42 are connected in series to provide a voltage signal generating circuit. The drive voltage Vd1 of the shunt regulator (42) is equal to the control resistance voltage dividing circuit (R1
1, R12), and the terminal voltage Vs1 of the photocoupler light emitter (41) is the resistance R11.
It is generated by the circuit constant of the voltage signal generation circuit (R110, 41, 42) itself including 0. The first secondary power supply system path L1 includes a direct current generating diode D1 and smoothing capacitors C11 and C12.

Next, the second secondary power system path L2 is drawn from the other secondary winding CL2 of the transformer Tr, and the voltage control I
C45, a diode D2 for generating direct current, and capacitors C21 and C22 for smoothing are formed.

In the power supply device having such a configuration, the voltage (+ V1) of the first secondary power supply (+ V1 to GND) fluctuates and becomes higher than the set voltage, and the drive voltage Vd increased accordingly.
When 1 becomes higher than the reference voltage, the shunt regulator (4
2) is turned on, and a voltage signal (light amount) is generated from the photocoupler light emitter 41. Therefore, according to the voltage signal (light quantity) received by the photocoupler light receiver 35, the voltage control circuit 3
0 (33, 34, 35) is 1 to the transformer Tr (31)
Control the next power supply. Here, the first secondary power supply voltage (+ V
1) is returned to the set voltage for stabilization.

On the other hand, when the voltage (+ V1) becomes low and the driving voltage Vd1 which becomes low due to this becomes less than the reference voltage, the shunt regulator (42) is turned off.
No voltage signal (amount of light) is emitted from the photocoupler light emitter 41. In this case, the voltage control circuit 30 controls to increase the inflow (primary power supply current I1) from the primary side to the secondary side. Therefore, the secondary voltage (+ V1) is stabilized while increasing the first secondary power supply current I2.

Since this power supply device is a so-called flyback system, the primary power supply side current I1 and the first secondary power supply side current I2 have the relationship shown in FIG.

On the other hand, the second secondary power source (+ V2−
The voltage (+ V2) fluctuation of (GND) is controlled by the winding ratio of the transformer Tr and the voltage control IC 45. That is, the first
The secondary power supply voltage + V
2 is not controlled as a feedback signal.

As described above, a plurality of secondary
In the power supply device that generates the next power supply, for example, when used in a printer, the drive power supply for the carrier and print head is 24V to 4V.
0V, 0-20A, logic power supply 5V-12V,
If it is 0 to 2 A, the detection unit, that is, the voltage signal generation circuit (R110, 41, 42) is basically provided in the secondary power supply path (L1) where the load fluctuation is large, and the voltage control circuit (3
3, 34, 35) must control the primary power supply to stabilize the voltage of the secondary power supply.

[0011]

Therefore, the second secondary power supply path L2 (voltage + V2) in which the voltage signal generating circuit (R110, 41, 42) is not provided is simply the winding ratio of the transformer Tr. Since it is indirectly controlled by, voltage + V2
Is very unstable. That is, even if the second secondary power supply voltage (+ V2) fluctuates and its value becomes high or low, the capability of the voltage control IC 45 is maintained as long as the primary power supply is common and the winding ratio of the transformer Tr is constant. If it exceeds, there is no control. Therefore, if the load increases, the second
As shown in FIG. 5, the secondary power supply voltage of 1 is extremely lowered, which is a disadvantage.

Further, when the voltage (+ V1) of the first secondary power source is lowered and the primary power source is controlled by the voltage control circuit 30, the voltage (+ V2) is also changed in accordance with the control so that the voltage (+ V2) is increased. I will end up. Although the voltage control IC 45 works, the power loss in this case is large and heat is generated. On the contrary, a case where the second secondary power supply voltage (+ V2) fluctuates low due to the primary power supply, that is, the first secondary power supply voltage (+ V1) may occur.

The above problems become more prominent as the number of secondary power supplies is increased. That is, as shown by the chain double-dashed line in FIG. 3, the third secondary power supply system path L3 (D3, C3) having a simpler structure extracted from the third secondary winding CL3 of the transformer Tr.
In 3), when the third secondary power source (+ V3 to GND) is generated, this voltage (+ V3) becomes very unstable for the above reason.

Each secondary power source (+ V2, + V3)
Voltage instability can be improved by using a chopper or dropper, for example, with a voltage-controlled secondary power source (+ V1) as a reference, but this is extremely costly and large. It has drawbacks and is difficult to adopt.

Further, in the above conventional power supply device, each secondary power supply system path (L1, L2) is provided with two separate transformers of the common transformer Tr.
Since it is drawn from the secondary windings (CL1, CL2), there is a problem that the winding of the transformer Tr is small at present with the tendency toward higher frequencies and the number of secondary power sources cannot be increased.

The above problem is inherently present even in the case of the forward system having the voltage-current relationship shown in FIG. 7 in the configuration shown in FIG. By the way, each of the secondary power supply paths L1 and L2
Includes diodes D12 and D22 and coils CL11 and C
L21 and are provided.

It is an object of the present invention to provide a power supply device for generating a plurality of secondary power supplies which has a small fluctuation in the secondary power supply voltage, a simple structure, a small size, and a low cost.

[0018]

According to the present invention, a secondary power source, which generates a plurality of secondary power sources from a primary power source via a transformer and has a signal generating element and a control element connected in series, is provided. In a power supply device that generates a plurality of secondary power supplies configured to stabilize the voltage of the secondary power supply by the cooperation of the provided voltage signal generation circuit and the voltage control circuit provided on the primary power supply side, A plurality of secondary power supply system paths are drawn from a common secondary winding of the transformer and have a common ground, and each secondary power supply system path has a terminal voltage of the signal generating element corresponding to the secondary power supply voltage. And a control resistance voltage divider circuit for generating a drive voltage for the control element, and two secondary power supply paths.
When the next power supply voltage is at the set voltage, it is formed so that each terminal voltage value generated by each signal resistance voltage divider circuit is the same and each drive voltage value generated by each control resistance voltage divider circuit is the same, It is characterized in that the voltage signal generating circuit is commonly connected to each secondary power supply system path.

[0019]

In the present invention having the above-mentioned structure, even if any secondary power supply system voltage becomes higher than the set voltage, the drive voltage generated by the control resistance voltage dividing circuit becomes higher than the reference voltage. The device for use is turned on. Further, the terminal voltage of the signal generating element also increases in accordance with the changed secondary power source voltage because the signal resistance voltage dividing circuit operates. Therefore, as a result of the voltage signal (light amount) having a magnitude corresponding to the voltage fluctuation being emitted from the photocoupler light emitting device forming the voltage signal generating circuit, the primary voltage control circuit returns the secondary power supply voltage to the set voltage. Control the power supply.

In this case, the drive voltage value and the terminal voltage value of the signal resistance voltage dividing circuit and the control resistance voltage dividing circuit become the same when the secondary power supply voltage is at the set voltage. Since it is formed as one, there is no sneak and no current loop as a voltage signal generating circuit is formed. Therefore, it is possible to accurately control the secondary power supply voltage having the largest voltage fluctuation range to the set voltage. The voltage fluctuation width of the other secondary power supply voltage is returned to the set voltage accordingly.

On the other hand, even if any one of the secondary power supply voltages becomes low, the control resistance voltage dividing circuit and the signal resistance voltage dividing circuit operate to generate a drive voltage and a terminal voltage corresponding to the secondary power supply voltage. .. Then, the control element is turned off and the voltage signal from the signal generating element disappears. Therefore, the voltage control circuit controls the primary power supply in the direction in which the secondary power supply voltage is the set voltage.

Therefore, even if any of the secondary power supply voltages fluctuates, the secondary power supply voltage having the largest fluctuation range is controlled to the set voltage, so that any of the secondary power supply voltages is stabilized at the same time. it can.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. A power supply device that generates a plurality of secondary power supplies has a basic configuration (rectifier circuit 20, voltage control circuit 30 as shown in FIG.
Etc. is the same flyback method as in the conventional example (FIG. 3), but the secondary power supply paths L1 and L2 are formed by drawing the ground GND from the common secondary winding CL of the transformer Tr in common, and The signal resistance voltage dividing circuits R110, R100, R120, R are provided in the respective secondary power supply paths L1, L2.
100 and control resistance voltage dividing circuits R11, R12, R21,
R22 and each secondary power supply voltage + V1, +
The signal generating element 4 when V2 is in the set voltage state
1 has the same terminal voltage values Vs1 and Vs2 (Vs1 = Vs
2), the driving voltage values Vd1 and Vd2 of the control element 42
Are configured to be the same (Vd1 = Vd2), and one voltage signal generation circuit (4
1, 42) and one voltage control circuit 3 provided on the primary power supply side.
0 (33, 34, 35), 2 with the largest voltage fluctuation range
The secondary power supply voltage is controlled to be the set voltage, and any secondary power supply voltage can be simultaneously stabilized.

The same or common parts as those of the conventional example (FIG. 3) such as the filter circuit, the rectifier circuit, the voltage control circuit and the like are designated by the same reference numerals and the description thereof will be simplified or omitted.

In FIG. 1, the two (plural) secondary power supply paths L1 and L2 are drawn from the common secondary winding CL of the transformer Tr, and the ground GND is also common. Extraction position A from the common secondary winding CL of the second secondary power supply path L2
Is the set voltage value (+ V1) of the first secondary power source and the second
It is determined based on the ratio with the set voltage value (+ V2) of the next power source. Therefore, the ratio of the secondary power supply voltages + V1 and + V2 to the primary power supply voltage is constant.

By the way, the resistance voltage dividing circuit for each signal has a resistor R1.
00 becomes common. First (second) secondary power supply path L
The resistor voltage divider circuit for signal provided in 1 (L2) includes resistors R110, R100 (R120, R10) connected in series between the secondary power sources (+ V1 to GND) [(+ V2 to GND)].
0) and the first (second) secondary power supply voltage + V1
When (+ V2) is the set voltage, the terminal voltage of the signal generating element (photocoupler light emitter) 41 becomes Vs1 (Vs2),
And the resistors R110 and R1 so that Vs1 = Vs2.
The resistance values of R20 and R100 are determined.

That is, which secondary power supply voltage + V1,
Also for + V2, if the voltage fluctuation range with respect to the set voltage is the same, the fluctuation range of the voltage signal (light amount) for feedback from the signal generating element 41 is the same and the absolute amount is also the same.

On the other hand, the first (second) secondary power supply path L1
The control resistance voltage dividing circuit provided in (L2) is the secondary power source (+
V1 to GND) [(+ V2 to GND)] connected in series between resistors R11 and R12 (R21 and R22), where the first (second) secondary power supply voltage + V1 (+ V2) is the set voltage Control element (shunt regulator) 4
The drive voltage for driving 2 (ON-OFF) is Vd1
The resistance values of the resistors R11, R12, R21, R22 are determined such that (Vd2) and Vd1 = Vd2.

Therefore, any secondary power supply voltage + V
Also for 1 and + V2, if the voltage fluctuation width with respect to the set voltage is the same, the fluctuation widths of the drive voltages Vd1 and Vd2 are the same and the absolute values are the same. The shunt regulator (42) of this embodiment has a drive voltage Vd1 = Vd
2 turns on when the reference voltage is 2.5 V or more, and turns off when the reference voltage is less than 2.5 V.

Thus, the voltage signal generating circuit (41, 4
2) is a voltage divider circuit for each signal (R110, R100,
R120, R100) and each control voltage divider circuit (R1
1, R12, R21, R22) are commonly connected to the respective secondary power supply system paths L1, L2.

The power supply device of this embodiment is used for a printer, and the first secondary power supply voltage + V1 is for driving the carrier and the print head, and the set voltage is +40 V, and the second secondary power supply. Voltage + V2 is for logic and the set voltage is + V
It is set to 20V.

Next, the operation of this embodiment will be described. now,
It is assumed that the first secondary power supply voltage + V1 fluctuates due to carrier driving and drops to + 40V or less.

Then, the first control resistance voltage dividing circuit R1
1, the drive voltage Vd1 detected by R12 drops to less than 2.5V which is the reference voltage. Therefore, the shunt regulator (42) is turned off.

At this time, since the secondary winding CL of the transformer Tr is shared, the second secondary power supply voltage + V2 also drops by the same rate as the voltage drop of the first secondary power supply voltage + V1. The drive voltage Vd2 detected by the control resistance voltage dividing circuits R21 and R22 is also the same as the previous drive voltage Vd1. That is, even if any of the secondary power supply voltages + V1 and + V2 changes, the drive voltage Vd1 = Vd2 changes accordingly. That is, no loop is formed and accurate detection is possible.

Thus, since the voltage signal (light amount) from the signal generating element 41 is cut off, the voltage control circuit 30 causes the primary power supply to restore the first secondary power supply voltage + V1 to the set voltage (+ 40V). Control the voltage. When the first secondary power supply voltage + V1 is restored to the set voltage (+ 40V), the second secondary power supply voltage + V2 also returns to the set voltage (+ 20V) accordingly. This is because the secondary winding CL of the transformer Tr is shared.

On the other hand, when the carrier is stopped and the load on the first secondary power supply path L1 is reduced so that the first secondary power supply voltage + V1 exceeds + 40V, the first control resistance voltage dividing circuit R11 is generated. , R12 detected by the drive voltage Vd1 (= Vd
In 2), the reference voltage is 2.5 V or higher. Then, the shunt regulator (42) is turned on.

At the same time, the terminal voltage Vs1 generated by the first signal resistance voltage dividing circuits R110 and R100 is also the first.
It becomes higher according to the fluctuation range of the secondary power supply voltage + V1. Therefore, the voltage signal (light amount) from the photocoupler light emitter (41) increases, and this time the voltage control circuit 30 changes the first
The primary power supply is controlled so that the secondary power supply voltage + V1 of (1) is returned to the set voltage (+ 40V).

At this time, the second resistance voltage dividing circuit for signal R12
The terminal voltage Vs2 generated by 0 and R100 is also the same as the terminal voltage Vs1 because the second secondary power supply voltage + V2 is increased with the variation of the first secondary power supply voltage + V1. .. In other words, the signal resistance voltage dividing circuit R11
As described above, 0, R100, R120, and R100, even if any of the secondary power supply voltages + V1 and + V2 fluctuate, as in the case of the control resistance voltage dividing circuits R11, R12, R21, and R22, the fluctuation components. The terminal voltages Vs1 and Vs2 can be generated so as to generate a voltage signal (light amount) according to

Thus, one of the secondary power supply paths L1,
There is a load change in L2, and the secondary power supply voltage value + V1, +
Even if V2 changes up and down, one voltage signal generation circuit (4
1, 42) and one voltage control circuit (33, 34, 35)
Can be used to automatically adjust the respective secondary power supply voltages + V1 and + V2 to the respective set voltages (+ 40V, + 20V). Therefore, the load current (A) of each of the secondary power supply paths L1 and L2
And the voltage (V) are as shown in FIG. 2, and any of the secondary power supply voltages (+ V1, + V2) can be extremely stabilized.

That is, while the second secondary power supply voltage (+ V2) of the conventional example (FIG. 3) is extremely unstable as shown in FIG. 5, the second secondary power supply of this embodiment having the same configuration is used. As shown in FIG. 2, the voltage (+ V2) can dramatically improve voltage stabilization regardless of load fluctuation.

Even if the third secondary power supply path (L3) shown by the chain double-dashed line in FIG. 3 is provided in this embodiment, as long as the signal and control resistance voltage dividing circuit is provided, It is obvious that the third secondary power supply voltage (+ V3) can be stabilized as shown in FIG. 2, like the other secondary power supply voltages + V1 and + V2, unlike the state shown in FIG.

However, according to this embodiment, a plurality of (2
2) of the secondary power supply system L1 and L2
The ground G is commonly drawn out from the next winding CL,
Each of the secondary power supply paths L1 and L2 is provided with a signal resistance voltage dividing circuit R110, R100, R120, R100 and a control resistance voltage dividing circuit R11, R12, R21, R22, and each secondary power supply voltage + V1, When + V2 is at the set voltage (+ 40V, + 20V), the signal generating element 4
1 terminal voltage values Vs1 and Vs2 are the same (Vs1 = Vs
2) and the driving voltage values Vd1 and Vd2 are also the same (Vd1 = V
As the d2), the voltage signal generating circuits (41, 42) are each divided into two.
Since it is connected in common to the secondary power supply paths L1 and L2, one voltage signal generating circuit (4
1, 42) and one voltage control circuit 3 provided on the primary power supply side.
0 (33, 34, 35), any secondary power supply + V
Even if 1 and + V2 change, any secondary power supply voltage + V
1 and + V2 are both set voltage (+40
V, + 20V) can be quickly restored, and a plurality (two) of secondary power supply voltages (+ V1, + V2) can be accurately and smoothly stabilized.

Further, a plurality (two) of secondary power supply system paths L1,
Since L2 has a configuration in which one secondary winding CL of the transformer Tr is commonly formed and drawn out, the transformer Tr can be extremely miniaturized and has a wide adaptability capable of quickly responding to an increase in power supply frequency. On the other hand, if the size of the transformer Tr is fixed, the number of secondary power supply system paths can be greatly increased.

In addition, the resistor voltage divider circuits for signals and the resistor voltage divider circuits for control include resistors R110, R100, R120,
Since the configuration is simple in which R11, R12, R21, and R22 are connected, the device cost can be significantly reduced, and the voltage control accuracy can be significantly improved. Also, a voltage control IC
The power loss due to (45) is also eliminated.

In the above embodiment, the number of secondary power supply paths is two (L1, L2), but the number of paths can be three or more. Applies as is. Further, although the flyback type power supply device is used, it is also applicable to the case of the forward type.

[0046]

As described above, according to the present invention, a secondary power source side which generates a plurality of secondary power sources from a primary power source via a transformer and which has a signal generating element and a control element connected in series In a power supply device for generating a plurality of secondary power supplies configured to stabilize the voltage of the secondary power supply by cooperation of a voltage signal generation circuit provided in the power supply circuit and a voltage control circuit provided on the primary power supply side. , A plurality of secondary power supply system paths are formed from a common secondary winding of the transformer and have a common ground, and each of the secondary power supply system paths has terminals of the signal generating element corresponding to the secondary power supply voltage. In the case where a signal resistance voltage dividing circuit for generating a voltage and a control resistance voltage dividing circuit for generating a driving voltage for the control element are provided, and the secondary power supply voltage of each secondary power supply system path is at the set voltage. Generates a voltage divider circuit for each signal Are formed so that the respective terminal voltage values are the same and the respective driving voltage values generated by the respective control resistance voltage dividing circuits are the same, and the voltage signal generating circuit is commonly connected to the respective secondary power supply system paths. Therefore, the following effects are obtained.

1 regardless of the number of secondary power sources
With one voltage signal generation circuit and one voltage control circuit, it is possible to simultaneously stabilize all the secondary power supply voltages to the set voltages, regardless of which secondary power supply voltage changes.

Each of the signal resistance voltage dividing circuit and each control resistance voltage dividing circuit has a simple configuration by resistance connection, so that the device cost can be significantly reduced and highly accurate control can be performed.

Since only one secondary winding is required, the transformer can be made extremely small. Therefore, it is suitable for increasing the frequency of the power supply, and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention.

FIG. 2 is a diagram for explaining the stability of each secondary power supply voltage.

FIG. 3 is a circuit diagram showing a conventional example (flyback method).

FIG. 4 is a diagram for explaining the relationship between the primary power supply current and the secondary power supply current.

FIG. 5 is also a diagram for explaining the problem.

FIG. 6 is a circuit diagram showing another conventional example (forward system).

FIG. 7 is a diagram for explaining the relationship between the primary power supply current and the secondary power supply current.

[Explanation of symbols]

10 Filter Circuit (Primary Power Supply) 20 Primary Power Supply 21 Rectifier 22 Smoothing Capacitor 30 Voltage Control Circuit 31 Control Winding 32 Base Winding 33 Power MOS (Voltage Control Circuit) 34 PWM Control IC (Voltage Control Circuit) 35 Photocoupler Receiver (Voltage control circuit) 40 Secondary power supply 41 Signal generating element (voltage signal generating circuit) 42 Control element (voltage signal generating circuit) 45 Voltage control IC Tr Transformer CL Common secondary winding CL1, CL2, CL3 Secondary winding L1 First secondary power supply system path L2 Second secondary power supply system path + V1 First secondary power supply voltage + V2 Second secondary power supply voltage Vd1, Vd2 Drive voltage Vs1, Vs2 Terminal voltage GND Ground R11, R12 Resistance (First control resistance voltage dividing circuit) R21, R22 Resistances (second control resistance voltage dividing circuit) R110, R100 Anti- (first signal resistor divider) R120, R100 resistance (resistance voltage dividing circuit for the second signal)

Claims (1)

[Claims] 1. A plurality of two power supplies are connected from a primary power source through a transformer.
By the cooperation of the voltage signal generation circuit provided on the secondary power supply side, which generates the secondary power supply and has the signal generation element and the control element connected in series, and the voltage control circuit provided on the primary power supply side. In a power supply device that generates a plurality of secondary power supplies configured to stabilize the voltage of the secondary power supply, a plurality of secondary power supply paths are drawn from a common secondary winding of the transformer and have a common ground. Then, in each of the secondary power supply paths, a signal resistance voltage dividing circuit that generates a terminal voltage of the signal generating element according to the secondary power supply voltage and a control resistance component that generates a drive voltage of the control element. And a voltage divider circuit is provided, and when the secondary power supply voltage of each secondary power supply path is at the set voltage, the terminal voltage values generated by the signal resistance voltage divider circuits are the same and the control resistance voltage divider circuits are The generated drive voltage values are the same A power supply device for generating a plurality of secondary power supplies, characterized in that the voltage signal generating circuit is commonly connected to each secondary power supply system.