CN100428602C - Power supply control circuit with set current-limiting mode - Google Patents

Abstract

The invention discloses a power supply control circuit with a set current-limiting mode, which is implemented by adopting an automatic detection mode, and is mainly characterized in that a control circuit for controlling a power supply output circuit of the power supply under a limited energy reference is implemented by adopting an automatic detection mode, the control circuit is provided with a current-limiting setting unit for electrical connection, provides a current-limiting setting value according to the output voltage of the power supply output circuit and outputs a current-limiting setting signal to a current-limiting switching unit, a switching contact is established on the output voltage of the power supply output circuit through the current-limiting setting unit, and the current-limiting switching unit receives the current-limiting setting signal to determine the state of the switching contact and provide a current-limiting detection value for a single group or multiple groups of output voltages to the current-limiting setting.

Description

Power supply control circuit with set current limit mode

technical field

The present invention relates to a control circuit of a power supply with a setting current limiting mode, in particular to a control circuit which can automatically detect the power output circuit of the power supply and is determined to be a single or multiple sets of output voltage limit energy benchmark comparison Fail-Safe Control Circuit.

Background technique

The main board of a general computer and its internal peripheral equipment (such as floppy hard drive, hard hard drive, optical drive, cooling fan, etc.) use different DC voltages. Therefore, the power supply used to supply the internal DC power of the computer host The converter must output at least two different DC powers to meet the different voltage requirements of various equipments in the mainframe computer.

Recently, due to the increasing demand of users for the working speed of computer systems, the power consumption required by the central processing unit and peripheral devices of the system has also increased, so that the power supply used in the computer system needs to provide larger power output, but different computer systems have different designs, and some system designs have a limited energy reference (maximum output power (MaxVA)) for the output port power, so it is necessary to design multiple sets of current limiting for this group of output ports Compare units to meet the use of high-level safety regulations. However, due to the ever-changing changes in computer systems, the power requirements of many peripheral devices are increasing, which will not meet the above-mentioned high-level safety requirements. It is equipped with peripheral functions. Therefore, the power supply that the user really needs must have a power control circuit design with a single or multiple output port current limit comparison function. For this reason, as shown in Figure 1, in each current limit The comparison unit is electrically connected with a selection circuit designed with a switch circuit, allowing users to determine single or multiple sets of current limiting protection failure functions according to the power of the connected peripheral equipment, although this prior art can solve most of the problems of users , but it must be done manually, which is very inconvenient to operate.

Contents of the invention

The main purpose of the present invention is to solve the above defects. In order to avoid the existence of the defects, the present invention provides a power supply control circuit with a setting current limiting mode, which is between the power output circuit and the protection circuit of a power supply. An overload failure control circuit is electrically connected between them. The power supply control circuit includes: a current limiting setting unit, which is electrically connected to the power output circuit and provides a current limiting setting value and a current limiting unit according to the output voltage of the power output circuit. Set the signal, and the current limit setting unit obtains the current limit detection value from the output voltage of the power output circuit and compares it with the current limit set value to determine to output a fail-safe signal to the protection circuit; a current limit switching unit, which It is electrically connected to the current-limiting setting unit and establishes switching contacts on the output voltage of the power output circuit, so that the current-limiting switching unit receives the current-limiting setting signal to determine the state of the switching contacts and provides current-limiting detection for single or multiple output voltages. measured value to the current limit setting unit.

Another object of the present invention is that the current limit setting unit also outputs a warning signal to an external warning unit to prompt the output voltage overload state.

Description of drawings

FIG. 1 is a schematic block diagram of an existing fail-safe control circuit;

2 is a schematic block diagram of a circuit according to a first embodiment of the present invention; and

FIG. 3 is a schematic block diagram of a circuit according to a second embodiment of the present invention.

Detailed ways

Relevant detailed description and technical contents of the present invention are as follows now in conjunction with the accompanying drawings:

Please refer to FIG. 2, which is a schematic circuit block diagram according to the first embodiment of the present invention. As shown in the figure: the present invention is a power supply control circuit with a set current limiting mode. The power supply is composed of a The power output circuit 10 provides multiple sets of DC output voltages V1-V4 to single or multiple loads L1-L4, and the power supply is equipped with a protection circuit 20 with an overload failure function. The power output circuit of a power supply of the present invention 10 and the protection circuit 20 are electrically connected to an overload failure control circuit, the control circuit mainly has a current limiting setting unit 30 which can be an IC integrated circuit, and the current limiting setting unit 30 is electrically connected to the power output circuit 10 And provide a current limit setting value and a current limit setting signal according to the output voltages V1-V4 of the power output circuit 10, and the current limit setting unit 30 obtains the current limit from the output voltages V1-V4 of the power output circuit 10 The detection value is compared with the current limit setting value to determine to output a fail-safe signal to the protection circuit 20. In the operation of the embodiment, each output voltage V1-V4 can be connected to a power converter R1-R4 with a resistor , using the power converters R1-R4 to generate a voltage drop to enable the current-limiting setting unit 30 to obtain the current-limiting detection value of the output voltage V1-V4, and the present invention also electrically connects the current-limiting setting unit 30 to a A current-limiting switching unit 40 that is a transistor or a switching circuit, the current-limiting switching unit 40 is to establish switching contacts S1-S4 on the output voltages V1-V4 of the power supply output circuit 10, so that the current-limiting switching unit 40 receives the current-limiting switching unit 40 The current setting signal is used to determine the state of the switching contacts S1-S4 to provide the current-limiting detection value to the current-limiting setting unit 30 for a single or multiple sets of output voltages V1-V4. In addition, the current-limiting setting unit 30 can also output A warning signal is sent to an external warning unit 50 which can be an LED display lamp or a buzzer to prompt the overload status of the output voltages V1 - V4 .

Fig. 3 shows the circuit block schematic diagram according to the second embodiment of the present invention, and the difference with the first embodiment is only that this embodiment adopts multi-group control circuit design, and its mode of operation is the same as that of the first embodiment, and the present invention will be described below implementation of:

Since the present invention adopts the automatic detection mode, the current-limit setting unit 30 of the control circuit can be set directly according to different regions or models when the power supply leaves the factory to provide a single or multiple sets of output voltages V1-V4 to provide limited The current detection value is sent to the current limit setting unit 30, which can effectively prevent the user from making mistakes in manual operation, or the current limit setting unit 30 of the present invention can be designed for IC integrated circuits, allowing users to Or it can be set, modified and controlled by the software environment, which will be more helpful for remote control, and the user can pay attention to the computer status at any time and make appropriate modifications.

The embodiment assumes that the power supply output circuit 10 outputs four sets of 12V DC output voltages V1-V4, and the DC output voltages V1-V4 are used to drive the first loads to the fourth loads L1-L4, and each output voltage V1-V4 is provided with The first to fourth power converters R1 to R4 (0.002Ω), taking the current-limited energy reference as MAX 240VA, the first load to the fourth load L1 to L4 can withstand a current value of 20A. In the case of one setting, if the current limiting setting state of the current limiting setting unit 30 is a single-group current limiting mode, the current limiting switching unit 40 is in a completely open state, so that the first power converter to the fourth power converter R1 ~R4 individually perform the voltage drop action. When the first load~fourth load L1~L4 exceeds 20A due to abnormal operation, the current limit detection value will be lower than 11.96V (the limit calculated by the current limit setting unit 30 due to the voltage drop method) The current setting value is 12V-20A*0.002Ω=11.96V), at this time, the current limiting setting unit 30 will output a fail-safe signal to the protection circuit 20, and the protection circuit 20 will decide whether to stop the power output, attention should be paid Notably, since the first load to the fourth load L1 to L4 may only be temporarily or slightly overloaded due to operating environment temperature, input power fluctuations or other factors, since the present invention adopts the integrated circuit automatic detection mode, therefore, Under predictable conditions, the present invention can define an estimated value for the current limit setting value of the current limit setting unit 30, such as 105% to 120%, so that the transient or slight overload phenomenon will not cause the power supply to immediately A protective effect is performed, making the present invention more flexible in operation.

In the second setting situation, it is assumed that the current limiting setting state of the current limiting setting unit 30 is a multi-group current limiting mode, and the current limiting switching unit 40 is in a completely closed circuit state, so that the first power converter to the fourth power converter R1 ~R4 collectively executes the voltage drop action, assuming that the operating current values of the first load ~ the fourth load L1 ~ L4 are 25A, 18A, 12A, 21A respectively, since the first power converter ~ the fourth power converter R1 ~ R4 are connected in parallel to calculate Current limit detection value, and the current limit detection value obtained by the current limit setting unit 30 is: 12V-[(25A+18A+12A+21A)*0.002Ω]/4=11.962V, at this time, although The current value of the first load L1 and the fourth load L4 exceeds the original set value of a single group, but due to the parallel connection setting, the power supply protection circuit 20 will not operate, but the present invention can use this current limiting setting The unit 30 outputs a warning signal to an external warning unit 50 which can be an LED display lamp or a buzzer to prompt the first load L1 and the fourth load to be in the heavy-load state of the output voltage V1 and V4, which is the same as the first setting situation, limited The current limiting setting value of the current setting unit 30 can define an estimated value such as 105% to 120%, so that the short-term or slight overload phenomenon will not cause the power supply to immediately perform the fail-safe effect of the protection circuit 20, and make this The invention is more flexible in operation.

The present invention is also applicable to the setting state that 3 groups of output voltages V1~V3 are integrated detection current limiting, 1 group of output voltage V4 is single group detection current limiting, or 2 groups of output voltages V1~V2, V3~V4 are respectively Integrated detection current limit, or 2 sets of output voltages V1~V2 are integrated detection current limit, and the other 2 sets of output voltage V3~V4 are single detection current limit, the setting and calculation method of current limit comparison is the same as above.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (8)

1. A power supply control circuit with a set current-limiting mode is an overload failure control circuit electrically connected between a power output circuit and a protection circuit of a power supply, characterized in that the power supply control Circuit includes: A current limit setting unit, which is electrically connected to the power output circuit and provides a current limit setting value and a current limit setting signal according to the output voltage of the power output circuit, and the current limit setting unit is from the The output voltage of the power supply output circuit is compared with the current limit detection value and the current limit set value to determine to output a fail-safe signal to the protection circuit; A current-limiting switching unit, which is electrically connected to the current-limiting setting unit and establishes a switching contact on the output voltage of the power output circuit, so that the current-limiting switching unit receives the current-limiting setting signal to determine The switching contact state provides a current limit detection value to the current limit setting unit for a single or multiple sets of output voltages. 2. The power supply control circuit with setting current limiting mode according to claim 1, wherein the current limiting setting unit is provided with a power converter on the output voltage of each power supply output circuit to obtain Current limit detection value. 3. The power supply control circuit with a set current-limiting mode according to claim 2, wherein the power converter is a resistor. 4. The power supply control circuit with setting current limiting mode according to claim 1 or 2, wherein the current limiting setting unit also outputs a warning signal to an external warning unit to remind the output voltage overloaded state. 5 . The power supply control circuit with a set current-limiting mode according to claim 4 , wherein the external warning unit is an LED display light. 6 . 6. The power supply control circuit with a set current-limiting mode according to claim 4, wherein the external warning unit is a buzzer. 7. The power supply control circuit with setting current limiting mode according to claim 1, wherein the current limiting setting unit is an IC integrated circuit. 8. The power supply control circuit with a settable current-limiting mode according to claim 1, wherein the current-limiting switching unit is a transistor.

Images