Autonomous current sharing control circuit

Abstract

The utility model discloses an autonomous current sharing control circuit. The control circuit comprises an output current detection part, a current signal processing part and an output voltage adjusting part. When the outputs of a plurality of power supplies are connected in parallel, the output current of the switching power supply is sampled through a current detection resistor, an initial current detection signal is amplified in a fixed proportion through an operational amplifier to obtain a current detection voltage signal, and the current detection voltage signals of each parallel power supply are connected together through a D9 and an R6 to obtain a current-sharing bus voltage Vs. A current detection voltage signal is transmitted to the negative end of the operational amplifier, a current-sharing bus voltage is transmitted to the positive end of the operational amplifier, and an error signal is obtained through proportional integral operation. The error signal adjusts a given reference value of a power supply output voltage feedback loop, the magnitude of the output voltage is adjusted, and the purpose of current sharing is achieved. The control circuit has the advantages of being simple, easy to debug, stable in work, good in current sharing effect, high in reliability, wide in application range and the like.

Description

TECHNICAL FIELD

[0001] The utility model relates to a power supply circuit, more particularly to a control circuit for parallel use of self-current-sharing multiple power supplies. BACKGROUND

[0002] At present, the wide application of a large number of electronic devices, especially computers, communications, space stations, etc. requires to build a power supply system with large power, safety and reliability, and uninterrupted power supply. If a single power supply is used, the converter will inevitably handle huge power and high voltage stress, which brings difficulties to the selection of power devices, switching frequency and power density. And once a single power supply fails, the entire system will collapse. The use of multiple power supply modules to improve the output of large power is a direction of power supply technology development. Each module in the system handles less power, solving the problems encountered by the single power supply.

[0003] However, when a module cannot provide the required current of the load, multiple modules are used in parallel to provide the total load. Since the output voltage of each module cannot be completely consistent, the output impedance characteristics will also be different. Simply connecting the modules in parallel cannot guarantee that the output currents of each module are completely consistent. It is possible that some modules are fully loaded while others are idle. We know that both idle and full load operation of the module are not the best operating state, and the overall life of the system can be imagined.

[0004] The existing power supply output parallel generally cannot realize the active current-sharing function. Due to the large load difference between the parallel power supplies, the output voltage of the power supply with large load is reduced more, and the load current of this power supply is reduced through this way to realize parallel operation. This multi-machine parallel operation will lead to unbalanced load of each power supply, which cannot work in the best efficiency range, and the heat is unbalanced, and even some individual power supplies will operate in overload, which will reduce the reliability of the entire power supply system. The existing current-sharing method has a relatively complex working principle and is difficult to debug, or a digital power supply realizes current-sharing through software control. UTILITY MODEL CONTENTS

[0005] The utility model is exactly designed to solve the above technical problems and provides a self-current-sharing control circuit.

[0006] The utility model adopts the technical scheme that:

[0007] A self-current-sharing control circuit, the control circuit includes an output current detection part, a current signal processing part and an output voltage regulation part.

[0008] The output current detection part power output current flows through the current detection resistor R1, samples the power output current, and obtains an initial sampling voltage Vc. The sampling voltage Vc is amplified by a fixed ratio by the respective operational amplifier U1A, and the current detection voltage Vi of each power supply is obtained. At the same time, the current detection voltage signals of each parallel power supply are connected together through D9 and R6 to obtain the bus voltage Vs.

[0009] The current signal processing part connects the sampling voltage Vi of each power supply to the negative terminal of the corresponding operational amplifier U1B, and connects the bus voltage Vs to the positive terminal of the operational amplifier U1B. The error voltage VEI is obtained by proportional integral operation. When the current detection voltage Vi is lower than the bus voltage Vs, the error voltage VEI rises.

[0010] When the current sharing mode is started, the output voltage adjustment part controls the output reference voltage Vref according to the error voltage VEI and the reference source VCC_2.5V and VCC_5V of the power supply main feedback loop, and realizes current sharing.

[0011] The output current detection part of the self-determined current sharing control circuit includes a current detection resistor R1, an operational amplifier U1A, and its auxiliary circuit. The output current flows through the current detection resistor R1 to obtain an initial sampling voltage Vc. The initial sampling voltage Vc is connected to the negative terminal of the operational amplifier U1A through the resistor R3, and the positive terminal of the operational amplifier U1A is connected to GND through the resistor R2. The operational amplifier U1A amplifies 100 times to obtain the current detection voltage Vi.

[0012] The current signal processing part of the self-determined current sharing control circuit includes a diode D9, an operational amplifier U1B, and its auxiliary circuit. The current detection voltages Vi of all parallel power supplies are connected together through the diode D9 and the resistor R6 to obtain the bus voltage Vs. The current detection voltage Vi is connected to the negative terminal of the operational amplifier U1B through the resistor R8, and the bus voltage Vs is connected to the positive terminal of the operational amplifier U1B through the resistor R7. The error voltage VEI is obtained by proportional integral operation (PI operation) through the operational amplifier U1B. Because of the diode, the Vs voltage value is taken as the maximum value of the Vs values of multiple parallel power supplies, and then the positive terminal of the operational amplifier U1B is given.

[0013] The output voltage regulating part of the self-determined current sharing control circuit comprises a transistor Q1, resistors R11 and R12, reference sources VCC_5V and VCC_2.5V; the error voltage VEI is connected with the collector of the transistor Q1, the reference source VCC_5V is connected with the base of the transistor Q1 through the resistor R11, the reference source VCC_2.5V is connected with the emitter of the transistor Q1 through the resistor R12, and the emitter output voltage value of the transistor Q1 is taken as the power main circuit feedback reference voltage Vref.When the load current of the power supply is lower than the bus voltage Vs, then U1B is operated to make VEI rise, the rising VEI can raise the value of Vref, so that the output voltage and the output current rise until the load current of the power supply approaches the average current value and reaches the current sharing accuracy requirement range.

[0014] The base of the transistor Q1 is connected with GND through a control current sharing switch.

[0015] The operational amplifiers U1A and U1B are an integrated operational amplifier with the model number of LM2904DGKR.

[0016] The current detection resistor R1 is a high-precision resistor with the parameters of 0.01Ω / 2512 / 3W.

[0017] The reference source VCC_5V is a 5V voltage stabilizing source, and the reference source VCC_2.5V is a 2.5V voltage stabilizing source.

[0018] The output current collecting part of the utility model samples the output current of the switching power supply, then the information processing part is operated to process the current detection information, finally the output voltage regulating part adjusts the output current by adjusting the high and low of the switching power supply output voltage, and current sharing is realized. The current sharing scheme has the characteristics of simple circuit, easy debugging, good current sharing effect, high reliability and the like.

[0019] 1, working principle

[0020] The detection device is divided into the following parts

[0021] The output current detection part: the power output current is sampled through the current detection resistor, the sampling signal is amplified by the operational amplifier at a fixed ratio, and the current detection voltage signal is obtained.

[0022] Current signal processing part: the current detection voltage signal is given to the negative end of the operational amplifier, and the current bus voltage is given to the positive end of the operational amplifier, and the error voltage is obtained by proportional integral operation.

[0023] Output voltage regulation part: the error voltage of the information processing part controls the output voltage value by regulating the reference voltage value of the main feedback loop of the power supply, so as to realize current sharing.

[0024] 2. Characteristics of the device

[0025] ① Improve efficiency, reduce heat, and effectively improve reliability.

[0026] The implementation of the technical scheme of the utility model makes the current sharing of the multi-machine parallel power supply, each power supply works in the best working interval, the efficiency is high, the heat is reduced, and the reliability is improved.

[0027] ② Simple circuit, stable operation.

[0028] The circuit principle of the technical scheme of the utility model is simple, easy to debug, and stable in operation.

[0029] ③ Wide application range

[0030] The technical scheme of the utility model can make the multi-machine parallel current sharing of the power supply, allow more power supply to be used in parallel, increase the power of the overall power supply installation, and can be applied to various devices requiring high power electrical equipment, and is suitable for various application occasions.

[0031] The utility model has the advantages of simple circuit, easy debugging, stable operation, good current sharing effect, high reliability, wide application range, etc. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 The utility model is a principle block diagram.

[0033] Figure 2 The utility model is a principle block diagram in the power supply system. DETAILED DESCRIPTION

[0034] The utility model will be further described below in combination with the drawings and examples.

[0035] As shown in Figure 1 and 2 The utility model is a kind of self-acting current control circuit, and the control circuit includes output current detection part, current signal processing part and output voltage regulation part;

[0036] The output current detection part power output current flows through the current detection resistor R1, samples the power output current to obtain the initial sampling voltage Vc, and the sampling voltage Vc is amplified by a fixed ratio by the respective operational amplifier U1A to obtain the current detection voltage Vi of each power supply. Meanwhile, the current detection voltage signals of each parallel power supply are connected together through D9 and R6 to obtain the bus voltage Vs.

[0037] The current signal processing part connects the sampling voltage Vi of each power supply to the negative terminal of the corresponding operational amplifier U1B, and connects the bus voltage Vs to the positive terminal of the operational amplifier U1B to obtain the error voltage VEI through proportional integral operation. When the current detection voltage Vi is lower than the bus voltage Vs, the error voltage VEI rises.

[0038] When the current sharing mode is turned on, the output voltage adjustment part controls the output reference voltage Vref according to the error voltage VEI and the reference sources VCC_2.5V and VCC_5V of the power supply main feedback loop to realize current sharing.

[0039] The output current detection part of the self-determined current sharing control circuit includes the current detection resistor R1, the operational amplifier U1A and its auxiliary circuit. The current detection resistor R1 is connected between Vc and GND. The output current flows through the current detection resistor R1 to obtain the initial sampling voltage Vc. The initial sampling voltage Vc is connected to the negative terminal of the operational amplifier U1A through the resistor R3. The positive terminal of the operational amplifier U1A is connected to GND through the resistor R2. The operational amplifier U1A amplifies 100 times to obtain the current detection voltage Vi.

[0040] The current signal processing part of the self-determined current sharing control circuit includes the diode D9, the operational amplifier U1B and its auxiliary circuit. The current detection voltages Vi of all parallel power supplies are connected together through the diode D9 and the resistor R6 to obtain the bus voltage Vs. The current detection voltage Vi is connected to the negative terminal of the operational amplifier U1B through the resistor R8. The bus voltage Vs is connected to the positive terminal of the operational amplifier U1B through the resistor R7. The operational amplifier U1B performs proportional integral operation (PI operation) to obtain the error voltage VEI. The diode prevents voltage backflow, so that the Vs voltage value is the maximum among the Vs values of multiple parallel power supplies, and then is input to the positive terminal of the operational amplifier U1B.

[0041] The autonomous current sharing control circuit, the output voltage regulating part comprises a transistor Q1, resistors R11 and R12, reference sources VCC_5V and VCC_2.5V; the error voltage VEI is connected to the collector of the transistor Q1, the reference source VCC_5V is connected to the base of the transistor Q1 through the resistor R11, the reference source VCC_2.5V is connected to the emitter of the transistor Q1 through the resistor R12, and the emitter output voltage value of the transistor Q1 is taken as the power main feedback reference voltage Vref. When the load current of the power supply is lower than the bus voltage Vs, U1B is operated to make VEI rise, and the rise of VEI will raise the value of Vref, so that the output voltage and the output current rise until the load current of the power supply approaches the average current value and reaches the current sharing accuracy requirement range.

[0042] The autonomous current sharing control circuit, the base of the transistor Q1 is connected to GND through a current sharing switch. When the power supply is operated alone, the current sharing switch is in a connected state, and the Q1 transistor is turned off, so that the current sharing circuit has no effect on the operation of the single machine.

[0043] The autonomous current sharing control circuit, the operational amplifiers U1A and U1B are an integrated operational amplifier, and the model is LM2904DGKR.

[0044] The autonomous current sharing control circuit, the current detection resistor R1 is a high-precision resistor with parameters of 0.01Ω / 2512 / 3W.

[0045] The autonomous current sharing control circuit, the reference source VCC_5V is a 5V voltage stabilizer, and the reference source VCC_2.5V is a 2.5V voltage stabilizer.

[0046] The implementation example is as shown in the figure. Figure 2 As shown in the figure, the current data information collection: the resistor R1 is a 0.01Ω current detection resistor, the output current is collected to obtain the initial current sharing bus voltage Vs, and the current detection voltage Vi is obtained by amplifying 100 times through the operational amplifier U1A.

[0047] The current signal processing part: the current detection voltage Vi is connected to the current sharing bus end Vs through a diode and a resistor in series, and the other end is connected to the negative end of the operational amplifier U1B. The current sharing Vs ends of all parallel power supplies are connected together, and the Vs voltage value is taken as the maximum value of the Vs values of the multiple parallel power supplies due to the diode preventing backflow, and then the Vs voltage value is given to the positive end of the operational amplifier U1B. VEI is obtained through the PI operation of the operational amplifier U1B.

[0048] Output voltage value regulation: VEI series 500K resistance, 2.5V reference source series 10K resistance, connect the two to get the reference voltage Vref of the main circuit feedback of the power supply. When the load current of the power supply is lower than the bus voltage Vs, then U1B operates to make VEI rise, VEI rising will raise the value of Vref, so that the output voltage rises, the output current rises, until the load current of the power supply is close to the average current value, reaches the current sharing accuracy requirement range.

[0049] When the power supply single machine runs, the control current sharing switch lead end OFF is shorted to GND, and the current sharing circuit has no effect on the single machine operation.

[0050] Parameter description:

[0051] Vi is the voltage across the current detection resistor amplified by 100 times;

[0052] VEI voltage value is between 0V-5V;

[0053] Vref=2.45V+VEI / 51;

[0054] The output voltage can be regulated within +2%.

[0055] The utility model is not limited to the above-mentioned best implementation, any person under the enlightenment of the utility model draws other any same or similar product of the utility model, all fall in the protection scope of the utility model.

Claims

1. An autonomous current sharing control circuit, characterized by: The control circuit comprises an output current detection part, a current signal processing part and an output voltage regulating part; The output current detection part is connected with the current detection resistor R1, and the output current of the power supply is sampled to obtain an initial sampling voltage Vc. The sampling voltage Vc is amplified by a fixed ratio by the operational amplifier U1A to obtain the current detection voltage Vi of each power supply. Meanwhile, the current detection voltage signals of each parallel power supply are connected together by D9 and R6 to obtain the bus voltage Vs. The current signal processing part is connected with the sampling voltage Vi of each power supply and the positive terminal of the operational amplifier U1B, and the bus voltage Vs is connected with the negative terminal of the operational amplifier U1B. The error voltage VEI is obtained by proportional integral operation. When the current sharing mode is started, the output voltage regulating part controls the output reference voltage Vref according to the error voltage VEI and the reference sources VCC_2.5V and VCC_5V of the main feedback loop of the power supply to realize current sharing.

2. The autonomous current-sharing control circuit of claim 1, wherein: The output current detection part comprises the current detection resistor R1, the operational amplifier U1A and the auxiliary circuit thereof. The output current flows through the current detection resistor R1 to obtain the initial sampling voltage Vc. The initial sampling voltage Vc is connected with the negative terminal of the operational amplifier U1A through the resistor R3, and the positive terminal of the operational amplifier U1A is connected with GND through the resistor R2. The current detection voltage Vi is obtained by amplifying the operational amplifier U1A by 100 times.

3. The autonomous current-sharing control circuit of claim 1, wherein: The current signal processing part comprises the diode D9, the operational amplifier U1B and the auxiliary circuit thereof. The current detection voltages Vi of all parallel power supplies are connected together by the diode D9 and the resistor R6 to obtain the bus voltage Vs. The current detection voltage Vi is connected with the negative terminal of the operational amplifier U1B through the resistor R8, and the bus voltage Vs is connected with the positive terminal of the operational amplifier U1B through the resistor R7. The error voltage VEI is obtained by proportional integral operation of the operational amplifier U1B.

4. The autonomous current-sharing control circuit of claim 1, wherein: The output voltage regulating part comprises the transistor Q1, the resistors R11 and R12, the reference sources VCC_5V and VCC_2.5V. The error voltage VEI is connected with the collector of the transistor Q1. The reference source VCC_5V is connected with the base of the transistor Q1 through the resistor R11, and the reference source VCC_2.5V is connected with the emitter of the transistor Q1 through the resistor R12. The output voltage value of the emitter of the transistor Q1 is taken as the feedback reference voltage Vref of the main loop of the power supply.

5. The autonomous current-sharing control circuit of claim 4, wherein: The base of the transistor Q1 is connected with GND through the current sharing switch.

6. The autonomous current-sharing control circuit of claim 1, wherein: The operational amplifiers U1A and U1B are an integrated operational amplifier, and the model is LM2904DGKR.

7. The autonomous current-sharing control circuit of claim 1, wherein: The current detection resistor R1 is a high-precision resistor, and the parameters are 0.01Ω / 2512 / 3W.

8. The autonomous current-sharing control circuit of claim 1, wherein: The reference source VCC_5V is a 5V voltage stabilizer, and the reference source VCC_2.5V is a 2.5V voltage stabilizer.

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