JP2000245059A - Power source supply circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make power supply timing or cut-off timing to loads of a power source supply circuit having n-kinds of output voltages coincide for all the n-kinds of outputs. SOLUTION: In this power source supply circuit, n-kinds of relays A 10 and relays B 13 are connected with n-kinds of outputs A and B. Contacts 10, 13 and 14, 15 of the relays 10, 13 are connected with parts between n-kinds of the outputs A and the outputs B and a load A 8 and a load B 9 of load part 5, respectively, in the manner of logic product. As a result, power supply timing or cut-off timing is made to coincide for all the outputs.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply circuit, and more particularly, to a power supply circuit for electronic equipment configured to be able to simultaneously supply a plurality of types of output voltages.

[0002]

2. Description of the Related Art A power supply circuit is an indispensable circuit for supplying electric power for normal operation of electric / electronic devices or elements constituting all electronic devices. Various circuits have been proposed and put into practical use. Have been.

For example, FIG. 3 shows a block diagram of a conventional general power supply circuit or power supply for supplying two types of output voltages. In FIG. 3, when the primary-side input switch 2 is turned on, power is supplied from, for example, a commercial power supply, and the secondary-side power generation unit 3 generates two types of required voltages. The secondary-side power output circuit 4 supplies the generated two types of voltages to the loads A, B 8, and 9 of the load unit 5. 2
The secondary power output circuit 4 has two overcurrent protection circuits 6 and 7 connected in parallel. The output A of the voltage V1 is equal to the load A8.
The output B of the voltage V2 is connected to a load B9 via a conductor.

[0004] Next, the operation of the power supply circuit of FIG.
This will be described with reference to the operation waveform diagram of FIG. The power supply device 1 outputs the power generated by the secondary power generation unit 3 to the load unit 5 at a time T0 after the primary input SW2 is turned on. In this circuit, the output A rises at time T1 due to the circuit configuration of the secondary-side power generation unit 3 and component tolerances (see FIG. 4B), and then the output B is asynchronous at time T2 after △ X seconds. (See FIG. 4C). In this case, for ΔX seconds, a relational expression of V1> V2 V2 = 0V is established between the output voltages of the output A and the output B.

Therefore, during the ΔX seconds, a current flows from the load A 8 having a high voltage value to the load B 9 having a low voltage value, and the load B
The overcurrent protection circuit B7 connected to the side 9 detects not a steady load of the load B9 but a current of the load A8 that occurs instantaneously. In this case, if the current capacity of the load A8 is larger than the current capacity of the load B9, the overcurrent protection circuit B7 sets the load A8
Has a circuit configuration capable of compensating for the current load capacity of

On the other hand, the operation after the time T3 when the primary-side input SW2 is shut off will be described. The output A falls at time T4 due to the component tolerance of the circuit configuration of the secondary-side power generation unit 3. Next, assume that the output B has fallen asynchronously at time T5 after ΔY seconds. In this case, during ΔY seconds, the output A
The following relationship is established between the output voltage and the output voltage of the output B. V2> V1 V1 = 0V

Therefore, for ΔY seconds, the load B having a high voltage value is used.
From 9, a current flows to the load A <b> 8 having a low voltage level.
Therefore, the overcurrent protection circuit A6 connected to the load A8 side
Detects the instantaneous current of the load B9 other than the load A8 which is a steady load. In this case, the current capacity of the load B9>
If the current capacity of the load A8 is overcurrent protection circuit A6
Has a circuit configuration capable of compensating the current capacity of the load B9.

[0008]

However, in the above-described conventional power supply circuit, in the secondary power output circuit of the power supply device having a plurality of output voltages, only a small amount after the primary power is turned on and after the primary power is turned off. Since the maximum load power value between multiple loads that occur at an appropriate time is determined as a reference for the compensation value in each of the overcurrent protection circuits, the instantaneous maximum load power and the subsequent steady load power value The larger the difference is, the larger the size of the overcurrent protection circuit of the secondary-side power output circuit becomes. When the load to be connected is CMOS (complementary MOS)
In the case of a transistor) device, there is a problem that latch-up may occur.

The reason is that the maximum load power value generated in a short time due to the time difference between the rise or fall of the plurality of types of output power after the primary power is turned on and after the power is turned off is determined by the load capacitance value of the overcurrent protection circuit. This is because the output voltage supplied to the load is supplied and cut off asynchronously with each other.

Therefore, an object of the present invention is to suppress the maximum load power generated during a short time (transient period) after turning on and off the primary power and without increasing the load current value of the overcurrent protection circuit. , An n-type output voltage to a load unit at the same time.

[0011]

In order to solve the above-mentioned problems, a power supply circuit according to the present invention employs the following characteristic configuration.

(1) A power supply device which is supplied with power via a primary-side input switch and includes a secondary-side power generation section for obtaining n kinds of output voltages, wherein the n-type output voltages are supplied to a load section In a power supply circuit for supplying / cutting off each load,
A power supply circuit comprising: n types of relays each connected to a different output voltage and having at least n contacts, wherein the contacts of the relay are connected by a logical product between the output voltage and the load unit.

(2) The power supply circuit according to (1), wherein the operating voltages of the n types of relays are set in accordance with the n types of output voltages.

(3) The power supply circuit according to (1) or (2), wherein the power supply device includes an overcurrent protection circuit corresponding to the n kinds of outputs.

(4) The contact points of the n relays are
The power supply circuit according to (1), wherein the power supply circuit is connected in series between the seed output and the load.

(5) The power supply circuit according to (1), wherein the n kinds of relays receive the n kinds of output voltages, and open and close the relay contacts with a preset relay operating voltage and cut-off voltage.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of a power supply circuit according to the present invention will be described in detail with reference to FIGS.

FIG. 1 is a block diagram of a preferred embodiment of a power supply circuit according to the present invention, and FIG. 2 is a waveform diagram for explaining its operation. The power supply circuit according to the present invention is shown in FIG.
Since a large number of circuit elements are used in the same manner as in the conventional power supply circuit shown in (1), the same reference numerals are used for the corresponding elements for convenience. 1 shows an example in which the power supply circuit also has two types of output voltages, but this is merely an example,
It is possible to have n types, that is, two or more types of output voltages.

In the power supply circuit shown in FIG.
When the primary-side input SW (switch) 2 is turned on, the secondary-side power generator 3 generates n (two in this example) output voltages. The secondary-side power generation unit 3 is connected to the load unit 5 via the secondary-side power output circuit 4 and supplies power thereto. This secondary-side power output circuit 4 includes n types of relays and n types of relays.
It consists of a kind of overcurrent protection circuit. More specifically, an overcurrent protection circuit A6, a relay A10,
The first contact 11 of the relay A and the first contact 14 of the relay B are connected. On the other hand, the output B of the voltage V2 is connected to the overcurrent protection circuit B7, the relay B13, the second contact 12 of the relay A, and the second contact 15 of the relay B.

As is clear from the comparison between the power supply circuit of FIG. 1 and the power supply circuit of FIG. 3, the feature of the power supply circuit according to the present invention resides in the secondary-side power output circuit 4. In particular, output A
And a relay A and a relay B for controlling the secondary side power output timing between the load A and the load B corresponding to the output B
It is connected as a kind of logical product (AND) circuit.

Further, a relay A1 is connected to the output A and the output B respectively.
By adding 0 and the relay B13, the contacts of the relay are opened and closed when the voltages V1 and V2 supplied to the relay reach the operating voltage or the open voltage for controlling the operation of the relay. Thereby, the supply / cutoff control of the timing of the output A and the output B supplied to the load unit 5 can be performed simultaneously.

Next, the operation of the power supply circuit of FIG. 1 will be described with reference to the waveform diagrams (a) to (e) of FIG. In FIG.
(A) is a primary-side input voltage waveform, (b) is a voltage waveform of an output A, (c) is a voltage waveform of an output B, (d) is a voltage waveform of an output A ′ supplied to a load A8, and (e). ) Is the voltage waveform of the output B 'supplied to the load B9.

The power supply 1 outputs the power generated by the secondary power generator 3 to the load 5 after time T0 when the primary input SW2 is turned on. In the power supply circuit of this specific embodiment, the output A rises at time T1 due to the circuit configuration of the secondary power generation unit 3, component tolerances, and the like. Next, it is assumed that the output B rises asynchronously at time T2 after △ X seconds. When the output A rises at time T1 and reaches the impressed voltage of the relay A10, the relay A10 outputs
, And the second contact 12 of the relay A connected to the output B are closed at the same time.

Next, when the output B rises at time T2 and reaches the operating voltage of the relay B13, the relay B13 is connected to the first contact 14 of the relay B connected to the output A and to the output B. The second contact 15 of the relay B is closed at the same time. Thus, at time T2, relay A
10 and all contacts of relay B13 will be closed,
The output A 'is simultaneously output to the load A8 and the load B9 of the load unit 5.
And an output B ′ can be supplied.

Similarly, in FIG. 2, the primary-side input SW2
Will be described. When the primary-side input SW2 is cut off at the time T3, the power supply device 1 cuts off the power supply from the secondary-side power generation unit 3 to the load unit 5. In this specific example, it is assumed that the output A of the secondary-side power generation unit 3 falls at time T4, and then the output B falls asynchronously at time T5 after ΔY seconds. When the output A falls at the time T4 and reaches the open voltage of the relay A10, the relay A10 outputs
, And the second contact 12 of the relay A connected to the output B is simultaneously opened. Next, when the output B falls at time T5 and reaches the open voltage of the relay B13, the first contact 14 of the relay B13 connected to the output A and the second contact 14 of the relay B13 connected to the output B The third contact 15 is simultaneously opened.
As described above, all the contacts of the relay A10 and the relay B13 are opened at the time T5, but at the time when the relay A10 or the relay B13 is opened earlier (in this case, at the time T4 when the relay A10 is opened), the load 5 is opened. The outputs A 'and B' for the loads A8 and B9 are simultaneously cut off.

As described above, the secondary power output timing between the secondary power generation unit 3 and the load unit 5, that is, the timing at which the output A 'and the output B' are supplied or cut off, is controlled.
The kind of relay is connected as an AND circuit. As a result, when the voltage supplied / interrupted to these relays reaches the operating voltage or the open voltage for controlling the operation of the relays, the contacts of the relays are simultaneously opened and closed to supply / output the output voltage supplied to the load unit. Blocking can be performed simultaneously.

In the above description, the case where the output A rises earlier and falls earlier than the output B has been described.
However, since the contacts of the relays A and B are connected as an AND circuit (or in series), the supply of the output A ′ and the output B ′ is similarly performed even if either of the output A and the output B rises or falls first. / Interruption timing can be matched.

The preferred embodiment of the power supply circuit according to the present invention has been described above. However, it should be understood by those skilled in the art that the present invention should not be limited to only such specific examples, and various modifications can be made without departing from the gist of the present invention.

[0029]

As will be understood from the above description, according to the power supply circuit of the present invention, the following various remarkable effects which cannot be obtained by the prior art can be obtained.

The first effect is that, in a power supply having n kinds of output voltages, the maximum load power value generated in a short time after the primary power is turned on and off is determined by the load capacity of the n kinds of overcurrent protection circuits. Since the circuit can be configured without increasing the value,
A power supply device at low cost can be realized. The reason is that the secondary side power output circuit has a function to monitor the timing of supply and cutoff of the output voltage with a relay circuit composed of logical products and to supply and cut off the power supply to the load at the same time. As a result, it is possible to suppress the generation of maximum load power that occurs a short time after the primary power is turned on and off, and to configure circuits and components without increasing the load capacitance value of the overcurrent protection circuit. It is. .

A second advantage is that a power supply device can be configured with improved reliability by avoiding the risk that a load receiving power supply may cause a latch-up phenomenon in the case of a CMOS structure device. The reason is that the supply and cutoff timings of the power supply voltage between the n types of loads that occur a short time after the primary power supply is turned on and off are determined by the secondary side power output circuit as described above.・ Supply timing of power supply voltage between n kinds of loads by adding a function that can simultaneously supply and cut off power to loads by monitoring the timing of cutoff with a relay circuit composed of logical products A circuit that can be controlled simultaneously is obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram of a preferred embodiment of a power supply circuit according to the present invention.

FIG. 2 is a waveform chart for explaining the operation of the power supply circuit shown in FIG. 1;

FIG. 3 is a block diagram of a conventional power supply circuit.

FIG. 4 is a waveform chart for explaining the operation of the power supply circuit shown in FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Power supply device 2 Primary-side input switch (SW) 3 Secondary-side power generation part 5 Load part 6,7 Overcurrent protection circuit 8,9 Load 10,13 Relay 11,12,14,15 Relay contact

Claims (5)

[Claims] 1. A power supply device which is supplied with power via a primary-side input switch and includes a secondary-side power generation unit for obtaining n types of output voltages, wherein the n types of output voltages are supplied to respective load units. A power supply circuit for supplying / interrupting to / from the load, wherein n kinds of relays each connected to the n kinds of output voltages and having at least n contacts are provided, and the contacts of the relays are connected to the output voltage and the load unit. A power supply circuit characterized by being connected by logical product. 2. The power supply circuit according to claim 1, wherein the operating voltages of the n types of relays are set according to the voltages of the n types of output voltages, respectively. 3. The power supply circuit according to claim 1, wherein the power supply device includes an overcurrent protection circuit corresponding to the n kinds of outputs. 4. The power supply circuit according to claim 1, wherein the contacts of the n relays are connected in series between the n types of outputs and the load. 5. The power supply according to claim 1, wherein the n types of relays receive the n types of output voltages, and open and close the relay contacts with a preset relay operating voltage and cut-off voltage. circuit.