JPH0545115Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to a multi-input power supply device that has a plurality of inputs and supplies power to a load. The present invention relates to a multi-input power supply device that includes a battery power supply for battery backup of a device, and that stabilizes the output of these power supplies and supplies it to a load.

(Prior Art) FIG. 9 is a block diagram showing an example of a conventional multiple input power supply device. In the figure, 1 is the first
A switching regulator is used, _for example, to output a plurality of stabilized DC voltages Eo ₁ and Eo ₂ . 2 is connected to the second via diode D2.
A backup converter to which the output voltage _e2 of the battery BT, which is the input of the main power supply unit 1, is applied.
The DC voltage Eo ₂ obtained by
is applied via. 3 is a charging circuit that inputs the DC voltage Eo ₂ and charges the battery BT.

An AC signal e ₁ as a first input is supplied, and while the main power supply device 1 is in operation, DC voltages Eo ₁ and Eo ₂ are supplied to each load (not shown). Also, DC voltage
Eo ₂ is applied to the backup converter 2 via diode D1 to provide the backup output BV. When the first input signal e1 is no longer supplied, the output of the battery BT is connected to the diode D2.
is applied to the backup converter 2 via
Provides backup output BV.

(Problem to be solved by the invention) The conventional multiple input power supply device configured as described above has a backup output when the main power supply device 1 is in operation.
Since the BV is output through the main power supply device 1 and the backup converter 2, there is a problem in that the output efficiency is extremely poor.

FIG. 10 is a conceptual diagram showing the power loss distribution in the conventional device shown in FIG. With the ratings shown in the figure, if the efficiency of the main power supply unit 1 is 80% and the efficiency of the backup converter 2 is 70%, the overall efficiency is:
It becomes 70.8%.

The present invention has been made in view of these problems, and its purpose is to realize a multi-input power supply device with a simple configuration and low power loss.

(Means for Solving the Problems) The present invention for solving the above-mentioned problems includes a transformer T, and a first input signal e1 applied to the primary winding of the transformer.
The first switch element SW turns on and off the
1, a first diode D1 that rectifies the output obtained from the secondary winding of the transformer, a second switch element SW2 that turns on and off the second input signal e2, and a second switch element that turns on and off the second input signal e2. a second diode D that rectifies the second input signal switched by
2, a smoothing circuit CH2, C2 that rectifies and smoothes the composite output V24 obtained at the butt point of each of the first and second diodes and supplies it to the load; and a smoothing circuit CH2, C2 that controls on/off of the first switch element. 1 control circuit CNT1, a second control circuit CNT2 that controls on/off of the second switch element, and a signal indicating disconnection of the input signal when the first input signal e1 becomes less than a specified value. and output the second
This is a multi-input power supply device comprising: an input disconnection detection circuit DT for activating the control circuit; and a synchronization means SYC for synchronizing the operations of the first and second control circuits.

(Operation) When the first input signal is supplied normally,
The first diode is conducting and the second diode of the transformer
The output obtained in the next winding is rectified and smoothed to become an output DC voltage, and when the first input signal falls below a specified value, the second control circuit is activated and the second input signal is changed to the second input signal. The output DC voltage is stabilized through the switch element and the second diode.

(Example) The first control circuit and the second control circuit operate in parallel during a period from when the first input signal drops below a specified value until it becomes zero level.

The synchronizing means controls the first and second switch elements to be turned on and off at a synchronized period while the first control circuit and the second control circuit are operating in parallel.

FIG. 1 is a block diagram showing an embodiment of the present invention. Here we have two input signals,
A power supply device that outputs two types of DC voltages Eo ₁ and Eo ₂ will be exemplified.

In the figure, T is the primary winding n ₁ , the secondary winding n ₂₁ ,
SW1 is a transformer having a transformer T having a transformer T and a first input signal e1 (this signal corresponds to a DC signal obtained by rectifying and smoothing an AC signal) to turn on _and off the primary winding _n1 of the transformer T. This is the first switch element that provides the D ₁ is the first diode that rectifies the output V ₂₂ obtained at the secondary winding n ₂₂ of the transformer T,
SW2 is a second switch element that turns on and off the second input signal e2, _D2 is a second switch element SW
2, the second input signal e is switched by
This is the second diode that rectifies the current. here,
The second input signal e2 corresponds to, for example, a battery output.

_D3 is a diode, CH2 is a choke, _C2 is a capacitor, and these are the first and second diodes.
A smoothing circuit is configured to rectify and smooth the output V ₂₄ obtained at the butt point of D ₁ and D ₂ to obtain a DC voltage Eo ₂ .

D ₄ , D ₅ are diodes that rectify the output V ₂₁ obtained at the secondary winding n ₂₁ of the transformer T, CH 1 is a choke, C ₁ is a capacitor, and these are the diodes D ₄ ,
It constitutes a smoothing circuit that smoothes the rectified output of _D5 , and obtains a DC voltage _Eo1 .

The DC voltages Eo ₁ and Eo ₂ obtained from each smoothing circuit are
Both are supplied to a load (not shown).

CNT1 is a control circuit that controls on/off of the first switch element SW1, and here, the DC voltage Eo ₁
is input, and this DC voltage Eo ₁ is the reference voltage
The on/off duty ratio of the first switch element SW1 is controlled so as to be maintained at a constant value corresponding to Vref1.

CNT2 is a control circuit that controls on/off of the second switch element SW2, which inputs a DC voltage Eo ₂ , and this DC voltage Eo ₂ becomes a reference voltage Vref2.
The on/off duty ratio of the second switch element SW2 is controlled so that it is maintained at a constant value corresponding to . DT is an input disconnection detection circuit that detects disconnection of the first input signal e1 and activates the second control circuit CNT2.

This input disconnection detection circuit DT receives a first input signal e.
1 becomes below a predetermined value, a signal indicating disconnection of the input signal is output, and the second control circuit CNT2 is activated.

As mentioned above, the first input signal is a signal obtained by rectifying and smoothing an AC signal, and when the power is cut off, the voltage level (value) changes from that point on.
Generally, it gradually decreases with a certain time constant and eventually reaches zero level.

Therefore, for example, there is a certain period of time after the power is turned off and the first input signal drops below a specified value until it reaches zero level, and during that period, the first control circuit CNT1 and the second Both control circuits CNT2 operate in parallel.

When the first and second control circuits operate in parallel,
Both an output _V22 resulting from the on/off of the first switch element SW1 and an output _V23 resulting from the on/off of the second switch element SW2 are output.

Here, immediately after the first input signal e1 becomes equal to or less than the specified value (immediately after the second control circuit is activated)
Although the contribution to the output voltage Eo2 due to the on/off of the second switch element SW2 is small,
As the first input signal e1 further decreases,
Its contribution gradually increases. The output V ₂₂ due to the on/off of the first switch element SW1 is
Output due to on/off of switch element SW2
When it becomes smaller than V ₂₃ , the output voltage Eo2 becomes the output V ₂₃ due to the on/off of the second switch element SW2.
It will be in a state where most of the power is supplied.

SYC is a synchronization means, and the first control circuit CNT1
and the second control circuit CNT2 are operating in parallel, the first and second switch elements SW1,
It plays the role of controlling the switch to turn on and off at a synchronized cycle with SW2. As a result, the power supply state according to the first input signal e1 is changed to the second input signal e2.
The switching to the power supply state is made smooth and continuous without causing any fluctuation in the output voltage Eo2. It also prevents beats from occurring in the output.

The operation of the device configured in this way will be explained next.

FIG. 2 is a signal waveform diagram of each part in a state where the first input signal e1 is normally supplied.

The first control circuit CNT1 turns on and off the first switch element SW1 at a repetition period _T1 as shown in a.
Turn off. The first input signal e1 is applied to the primary winding n ₁ of the transformer T via the first switch element SW1, and the rectangular wave output V ₂₁ as shown in b is applied to the secondary windings n ₂₁ and n ₂₂ . , we get V ₂₂ .

In this state, the second control circuit CNT2 is not activated by the input disconnection detection circuit DT and is stopped, and the second switch element SW2 is off as shown in c, and its output terminal is turned off. The voltage V ₂₃ is zero (therefore, the relationship V ₂₂ >V ₂₂ ), and the second diode D2 is non-conductive.

The rectangular wave output V ₂₁ generated in the secondary winding n ₂₁ is rectified by diodes D4 and D5, and then
CH1, DC voltage Eo ₁ smoothed by capacitor C ₁
becomes. Further, this DC voltage Eo ₁ is fed back to the first control circuit CNT1, and the DC voltage Eo 1 is fed back to the first control circuit CNT1.
controls the on/off time of the first switch element so that the DC voltage _Eo1 is maintained at a constant value corresponding to the reference voltage Vref1.

The square wave output V ₂₂ generated in the secondary winding n ₂₂ is V ₂₂ >
Since V ₂₃ , it passes through the first diode D1,
It is smoothed by a rectifier and smoothing circuit and becomes a DC voltage Eo ₂ . d indicates the signal _V24 at the butting point of the first and second diodes D1 and D2.

FIG. 3 is an operational waveform showing the operation when the first input signal e1 decreases.

When the first input signal e1 becomes less than a specified value, the input disconnection detection circuit DT detects this and starts the second control circuit CNT2. Second control circuit CNT2
The DC voltage Eo ₂ is fed back, and the second switch element SW2 is connected as shown in c to compensate for the drop in the DC voltage Eo ₂ due to the drop in the first input signal e1 and to make it equal to the reference voltage Vref2. Drive like this.

Here, the second control circuit CNT2 is synchronized with the operation of the first control circuit CNT1 by the synchronization circuit SYC, and the repetition period at which the second switch element SW2 is turned on is _T1 . It's summery.

d indicates a signal _V24 at the butt point of the first and second diodes D1 and D2, which is rectified and smoothed to become a DC voltage _Eo2 .

In this state, the value of the DC voltage Eo ₂ is almost controlled by the first control circuit CNT1,
The contribution rate by the second control circuit CNT2 is small.

When the value of the first input signal e1 further decreases from the specified value, V ₂₂ >V ₂₃ and the second diode D
2 becomes conductive, the output DC voltage Eo2 becomes,
Most of the signal is supplied from the second input signal e2 side.

FIG. 4 is an operation waveform diagram showing the operation when the first input signal e1 is zero (power outage state).

The output V ₂₁ of each secondary winding n ₂₁ , n ₂₂ of the transformer T,
V ₂₂ becomes zero as shown in a.

The second control circuit CNT2 turns on and off the second switch element SW2 at a repetition period _T1 as shown in b.
Turn off. The second input signal e2 is switched by the second switch element SW2, and the first,
The signal at the butt point of the second diodes D1 and D2 is as shown in c, and this is rectified and smoothed to become a DC voltage Eo ₂ .

FIG. 5 is a conceptual diagram showing the power loss distribution in the device of the present invention shown in FIG. Figure 9 Output 170W (2 types of output: 12V10A and 5V10A) similar to the conventional device
If so, the overall efficiency will increase to 76%.

In addition, in the conventional device shown in Figure 9, 5V, 10A (50W)
backup converter and 12V, 16A
(192W) main power supply is required, but according to the device of this invention, 5V, 10A (50W) and 12V, 10A
A main power supply with a capacity of 170W is sufficient to supply (120W), allowing the capacity of the main power supply to be reduced.

6 to 8 are block diagrams showing other embodiments of the present invention.

The embodiment shown in FIG. 6 uses the device shown in FIG. 1 to include a third switch element (here, one using a mag-amp is shown) SW3 between the secondary winding _n22 of the transformer T and the first diode D1. At the same time, a third switch element is connected so that the DC voltage Eo ₂ becomes a constant value corresponding to the reference voltage Vref2.
A third control circuit CNT3 is provided to control SW3.

In the embodiment of FIG. 7, the secondary windings n ₂₁ and n ₂₂ of the transformer T are shared by one winding n ₂₀ in the embodiment of FIG. 6.

In the embodiment shown in FIG. 8, a fourth switch element (here, an example using a mag-amp is shown) SW4 is inserted and connected between the secondary winding _n21 of the transformer T and the diode D4 in the apparatus shown in FIG. At the same time,
The fourth switch element SW4 is set so that the DC voltage _Eo1 becomes a constant value corresponding to the reference voltage Vref3.
A fourth control circuit CNT4 is provided. In this case, the first control circuit CNT1 has
The configuration is such that the DC voltage Eo ₁ does not return.

In each of the above-mentioned embodiments, the main power supply device includes one switch element SW1, which is one component, but two switch elements SW1 may be used. Further, the number of input signals and the number of output DC voltages are not limited to two.

(Effects of the invention) As explained in detail above, according to the invention,
With a simple configuration, a multi-input power supply device with low power loss and high efficiency can be realized. The device of the present invention is a power supply device that outputs a large number of DC voltages, and is effective when applied to a case where one DC voltage is to be backed up from a battery.

Further, in the present invention, the first input signal e1
When the voltage decreases below the specified value, the second control circuit is activated, and for a while it operates in parallel with the first control circuit, and eventually turns on and off by turning on and off the second switch element. The power supply is switched to the second input signal e2, and the first input signal e1
This has the advantage that switching from the power supply state caused by the input signal e2 to the power supply state caused by the second input signal e2 can be smoothly performed without causing any fluctuation in the output voltage.

[Brief explanation of the drawing]

Figure 1 is a configuration block diagram showing one embodiment of the present invention, Figures 2 to 4 are waveform diagrams to explain its operation, and Figure 5 is a conceptual diagram showing power loss distribution in the device shown in Figure 1. , Fig. 6 to Fig. 8 are block diagrams showing other embodiments of the present invention, Fig. 9 is a block diagram showing an example of a conventional device, and Fig. 10 shows power loss distribution in the device shown in Fig. 9. It is a conceptual diagram. T...Transformer, _n1 ...Primary winding, _n21 , _n22 ...
...Secondary winding, SW1, SW2, SW3...Switch element, _D1 to _D5 ...Diode, CNT1 to CNT
4...Control circuit, SYC...Synchronization circuit, DT...
Input disconnection detection circuit.

Claims (1)

[Claims for Utility Model Registration] A transformer T and a first input signal e1 to the primary winding of this transformer.
The first switch element SW turns on and off the
1, a first diode D1 that rectifies the output obtained from the secondary winding of the transformer, a second switch element SW2 that turns on and off the second input signal e2, and a second switch element that turns on and off the second input signal e2. a second diode D that rectifies the second input signal switched by
2, a smoothing circuit CH2, C2 that rectifies and smoothes the composite output V24 obtained at the butt point of each of the first and second diodes and supplies it to the load; and a smoothing circuit CH2, C2 that controls on/off of the first switch element. 1 control circuit CNT1, a second control circuit CNT2 that controls on/off of the second switch element, and a signal indicating disconnection of the input signal when the first input signal e1 becomes less than a specified value. and output the second
A multi-input power supply device comprising: an input disconnection detection circuit DT for activating a control circuit; and a synchronization means SYC for synchronizing operations of the first and second control circuits.