Current sharing circuit

Abstract

The utility model provides a current sharing circuit which is simple in circuit component, easy to debug, low in cost and wide in application range. One current sharing circuit is arranged in each power supply in parallel dual power supplies, ISHARE ports of the two power supplies are connected together, current is converted into a voltage signal through a sampling resistor RM1, the voltage signal is sent to an operational amplifier U1 to be amplified and enters a pin6 anti-phase end of the U1, the voltage signal of the pin6 anti-phase end of the U1 is compared with a pin5 in-phase end, and the current sharing circuit is connected with the power supply. After amplification, a higher voltage signal enters a pin5 in-phase end of a power supply internal U1 with low output voltage through ISHARE; in the power supply with low output voltage, the pin7 of the U1 outputs a high level, the pin7 of the operational amplifier U2 outputs a low level, the current of the light-emitting tube of the optocoupler PC1 is reduced, the output voltage is increased, and the output voltages of the two power supplies are consistent, so that the current sharing is realized.

Description

Technical Field

[0001] The utility model relates to the technical field of power supplies, in particular to a current sharing circuit. Background Art

[0002] In the existing power management, most important equipment (such as base stations, servers, etc.) require dual power backup. If one power supply is damaged, the other power supply continues to supply power. In order to effectively utilize the dual power supplies and extend the service life of the power supplies, the loads of the dual power supplies need to be shared as much as possible during use, so as to reduce the pressure on the power converter and improve the reliability of the parallel power supply system. However, in the prior art, some current sharing circuits have complex peripheral circuits and many devices, which are not applicable in many occasions. Some current sharing circuits are implemented through digital circuits, which require programming to implement and have high implementation costs. Summary of the invention

[0003] In order to solve the problem in the prior art that the peripheral circuit of the current sharing circuit is complex, resulting in limited usage scenarios or high implementation costs, the utility model provides a current sharing circuit, which has simple circuit components, easy debugging, low cost and wide application range.

[0004] The structure of the utility model is as follows: a current sharing circuit, characterized in that it includes: an optical coupler PC1, a load R2, resistors R1, VR1, RM1, R5~R19, diodes D1 and D2, a voltage zener diode ZD1, operational amplifiers U1 and U2, and capacitors C1~C7;

[0005] One end of the resistor RM1 is connected to the I-FB pin of the power output, the other end of the resistor RM1 is connected to one end of the load R2 and then grounded, the other end of the load R2 is connected to the cathode of the diode D2, and the V+ pin of the power output of the diode D2;

[0006] One end of the capacitor C7 is connected to one end of the resistor R18 and one end of the resistor R16 and then connected to the I-FB pin of the power output; the 2nd pin of the amplifier U1 is connected to the other end of the resistor R16, one end of the capacitor C6, one end of the resistor R14, and one end of the capacitor C4; the 3rd pin of the operational amplifier U1 is connected to the other end of the capacitor C6, one end of the resistor R17, and one end of the resistor R15; the 4th pin of the operational amplifier U1 is connected to one end of the capacitor C5, the other end of the resistor R15, the other end of the capacitor C7, the other end of the resistor R18, and the other end of the resistor R17 and then grounded; the 1st pin of the amplifier U1 is connected to the other end of the resistor R14, the other end of the capacitor C4, and one end of the resistor R12; the 8th pin of the amplifier U1 is connected to the other end of the capacitor C5, and the other end of the resistor R12 is connected to one end of the resistor VR1;

[0007] The other end of the resistor VR1 is connected to one end of the resistor R10 and one end of the resistor R9, the 5th pin of the operational amplifier U1 is connected to one end of the resistor R11, one end of the resistor R13, one end of the capacitor C3, and the other end of the resistor R10, the other end of the resistor R13 is used as the ISHRRE port of the power supply, the 6th pin of the operational amplifier U1 is connected to the other end of the resistor R9 and one end of the resistor R8, the 7th pin of the operational amplifier U1 is connected to the other end of the resistor R8 and one end of the resistor R7, the other end of the resistor R7 is connected to one end of the capacitor C2, the cathode of the voltage zener diode ZD1, and one end of the resistor R5, the anode of the voltage zener diode ZD1 is connected to the other end of the capacitor C2, the other end of the resistor R11, the other end of the capacitor C3 and then grounded;

[0008] Pin 6 of the operational amplifier U2 is connected to the other end of the resistor R5 and one end of the capacitor C1, pin 5 of the operational amplifier U2 is connected to one end of the resistor R6, the other end of the resistor R6 is connected to a 2.5V power supply, the other end of the capacitor C1 is connected to one end of the resistor R19, and pin 7 of the operational amplifier U2 is connected to the other end of the resistor R19 and the anode of the diode D1; the cathode of the diode D1 is connected to one end of the resistor R1, the other end of the resistor R1 is connected to the positive electrode of the optocoupler PC1 transmitter, the negative electrode of the optocoupler PC1 transmitter is grounded, the collector of the receiver of the optocoupler PC1 serves as a voltage output pin, and the emitter of the receiver of the optocoupler PC1 is grounded.

[0009] It is further characterized by:

[0010] The operational amplifiers U1 and U2 are implemented based on an operational amplifier chip of model LM358;

[0011] A resistor of the same type is connected in parallel to the resistor RM1.

[0012] The present application provides a current sharing circuit, in which a current sharing circuit in the present solution is respectively arranged inside each power supply in a parallel dual power supply, the ISHARE ports of the two power supplies are connected together, the current passes through the sampling resistor RM1, is converted into a voltage signal, is sent to the operational amplifier U1 for amplification and enters the pin6 inverting end of U1, the voltage signal at the pin6 inverting end of U1 is compared with the pin5 inverting end, and the higher voltage signal after amplification passes through ISHARE and enters the pin5 inverting end of the power supply with low output voltage inside U1; inside the power supply with low output voltage, pin7 of U1 outputs a high level, pin7 of the operational amplifier U2 outputs a low level, the light-emitting tube current of the optocoupler PC1 decreases, the output voltage increases, the output voltages of the two power supplies are consistent, and the current is shared; the current sharing circuit of the present application is implemented based on an analog circuit, which not only has a relatively simple circuit component, is easy to debug, and has a low cost, but can also be used as a general circuit for various application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 A circuit diagram of the current sharing circuit of the present application. DETAILED DESCRIPTION

[0014] like Figure 1 As shown, the utility model includes a current sharing circuit, characterized in that it includes: an optical coupler PC1, a load R2, resistors R1, VR1, RM1, R5~R19, diodes D1 and D2, a voltage-stabilizing diode ZD1, operational amplifiers U1 and U2, and capacitors C1~C7. In a specific implementation, amplifiers U1 and U2 are implemented based on an operational amplifier chip of model LM358.

[0015] One end of the resistor RM1 is connected to the I-FB pin of the power output (marked as I-FB in the figure), the other end of the resistor RM1 is connected to one end of the load R2 and then grounded, the other end of the load R2 is connected to the cathode of the diode D2, and the anode of the diode D2 is connected to the V+ pin of the power output.

[0016] One end of capacitor C7 is connected to one end of resistor R18 and one end of resistor R16 and then to the I-FB pin of the power output. Pin 2 of operational amplifier U1 is connected to the other end of resistor R16, one end of capacitor C6, one end of resistor R14, and one end of capacitor C4. Pin 3 of operational amplifier U1 is connected to the other end of capacitor C6, one end of resistor R17, and one end of resistor R15. Pin 4 of amplifier U1 is connected to one end of capacitor C5, the other end of resistor R15, the other end of capacitor C7, the other end of resistor R18, and the other end of resistor R17 and then to ground. Pin 1 of operational amplifier U1 is connected to the other end of resistor R14, the other end of capacitor C4, and one end of resistor R12. Pin 8 of operational amplifier U1 is connected to the other end of capacitor C5, and the other end of resistor R12 is connected to one end of resistor VR1.

[0017] The other end of the resistor VR1 is connected to one end of the resistor R10 and one end of the resistor R9. The 5th pin of the operational amplifier U1 is connected to one end of the resistor R11, one end of the resistor R13, one end of the capacitor C3, and the other end of the resistor R10. The other end of the resistor R13 serves as the ISHRRE port of the power supply. The 6th pin of the operational amplifier U1 is connected to the other end of the resistor R9 and one end of the resistor R8. The 7th pin of the operational amplifier U1 is connected to the other end of the resistor R8 and one end of the resistor R7. The other end of the resistor R7 is connected to one end of the capacitor C2, the cathode of the Zener diode ZD1, and one end of the resistor R5. The anode of the Zener diode ZD1 is connected to the other end of the capacitor C2, the other end of the resistor R11, the other end of the capacitor C3, and then grounded.

[0018] Pin 6 of operational amplifier U2 is connected to the other end of resistor R5 and one end of capacitor C1, pin 5 of operational amplifier U2 is connected to one end of resistor R6, the other end of resistor R6 is connected to a 2.5V power supply, the other end of capacitor C1 is connected to one end of resistor R19, pin 7 of operational amplifier U2 is connected to the other end of resistor R19 and the anode of diode D1; the cathode of diode D1 is connected to one end of resistor R1, the other end of resistor R1 is connected to the positive electrode of the light-emitting diode of optocoupler PC1, and the negative electrode of the light-emitting diode of optocoupler PC1 is grounded. The collector of the phototransistor of optocoupler PC1 is connected to the external PMW chip as an output pin, and the emitter of the phototransistor of optocoupler PC1 is grounded.

[0019] In the parallel dual power supplies, a current sharing circuit of the present application is set in each power supply, and the ISHARE ports of the two power supplies are connected together. When the current passes through the sampling resistor RM1, it is converted into a voltage signal, and the voltage signal is amplified by the operational amplifier U1;

[0020] Among them, the voltage signal size converted by RM1 = the current passing through * RM1 sampling resistance,

[0021] The power signal is amplified by amplifier U1 by a factor of R14 / R16+1.

[0022] The pin1 output voltage of the operational amplifier U1 passes through resistors R12, VR1 and R9 and enters the pin6 inverting terminal of U1. If the output voltage of the parallel power supply is set to be high and the output current is large, then the corresponding ISHARE voltage is high. After the voltage signal at the inverting terminal of pin6 of U1 is compared with the non-inverting terminal of pin5, the amplified higher voltage signal enters the non-inverting terminal of pin5 of U1 inside the power supply with low output voltage through ISHARE. After comparison with pin6 (inverting terminal) of U1, since the voltage signal of the external ISHARE is higher than the internal pin6 (inverting terminal), the pin7 of U1 inside the power supply with low output voltage outputs a high level (AUX-1.5V).

[0023] Inside the power supply with lower output voltage, it passes through resistors R7 and R5 and enters pin6 (inverting end) of operational amplifier U2, and is then compared with 2.5V of pin5 (non-inverting end) of operational amplifier U2; the voltage of Pin6 (inverting end) of U2 is equal to the voltage regulation value of regulator ZD1. Because the voltage of Pin6 (inverting end) of U2 is higher than that of pin5 (non-inverting end), pin7 of U2 outputs a low level, the light-emitting diode current of the optocoupler decreases, the duty cycle of the external PWM chip increases, the output voltage increases, the output voltages of the two power supplies are consistent, and current is shared.

[0024] In the specific implementation, the sampling resistor RM1 is a very important component, which needs to be implemented with a precision resistor with very small temperature drift, such as manganese copper wire; and according to actual needs, a high-precision resistor of the same type can be connected in parallel to the sampling resistor RM1 to further improve the sampling accuracy. The voltage regulator ZD1 stabilizes the voltage at the pin7 output terminal of the operational amplifier U1 to prevent the voltage entering the pin6 inverting terminal of the operational amplifier U2 from being too high. In actual application, the current sharing circuit of this application as a whole uses resistors with higher precision for current sampling, signal amplification, and voltage division, so that the current sharing effect is better.

Claims

1. A current sharing circuit, characterized in that: It includes: Optocoupler PC1, load R2, resistors R1, VR1, RM1, R5~R19, diodes D1 and D2, Zener diode ZD1, operational amplifiers U1 and U2, capacitors C1~C7; One end of the resistor RM1 is connected to the I-FB pin of the power output, the other end of the resistor RM1 is connected to one end of the load R2 and then grounded, the other end of the load R2 is connected to the cathode of the diode D2, and the V+ pin of the power output of the diode D2; One end of the capacitor C7 is connected to one end of the resistor R18 and one end of the resistor R16 and then connected to the I-FB pin of the power output; the 2nd pin of the amplifier U1 is connected to the other end of the resistor R16, one end of the capacitor C6, one end of the resistor R14, and one end of the capacitor C4; the 3rd pin of the operational amplifier U1 is connected to the other end of the capacitor C6, one end of the resistor R17, and one end of the resistor R15; the 4th pin of the operational amplifier U1 is connected to one end of the capacitor C5, the other end of the resistor R15, the other end of the capacitor C7, the other end of the resistor R18, and the other end of the resistor R17 and then grounded; the 1st pin of the amplifier U1 is connected to the other end of the resistor R14, the other end of the capacitor C4, and one end of the resistor R12; the 8th pin of the amplifier U1 is connected to the other end of the capacitor C5, and the other end of the resistor R12 is connected to one end of the resistor VR1; The other end of the resistor VR1 is connected to one end of the resistor R10 and one end of the resistor R9, the 5th pin of the operational amplifier U1 is connected to one end of the resistor R11, one end of the resistor R13, one end of the capacitor C3, and the other end of the resistor R10, the other end of the resistor R13 is used as the ISHRRE port of the power supply, the 6th pin of the operational amplifier U1 is connected to the other end of the resistor R9 and one end of the resistor R8, the 7th pin of the operational amplifier U1 is connected to the other end of the resistor R8 and one end of the resistor R7, the other end of the resistor R7 is connected to one end of the capacitor C2, the cathode of the voltage zener diode ZD1, and one end of the resistor R5, the anode of the voltage zener diode ZD1 is connected to the other end of the capacitor C2, the other end of the resistor R11, the other end of the capacitor C3 and then grounded; Pin 6 of the operational amplifier U2 is connected to the other end of the resistor R5 and one end of the capacitor C1, pin 5 of the operational amplifier U2 is connected to one end of the resistor R6, the other end of the resistor R6 is connected to a 2.5V power supply, the other end of the capacitor C1 is connected to one end of the resistor R19, and pin 7 of the operational amplifier U2 is connected to the other end of the resistor R19 and the anode of the diode D1; the cathode of the diode D1 is connected to one end of the resistor R1, the other end of the resistor R1 is connected to the positive electrode of the optocoupler PC1 transmitter, the negative electrode of the optocoupler PC1 transmitter is grounded, the collector of the receiver of the optocoupler PC1 serves as a voltage output pin, and the emitter of the receiver of the optocoupler PC1 is grounded.

2. The current sharing circuit according to claim 1, characterized in that: The operational amplifiers U1 and U2 are implemented based on an operational amplifier chip of model LM358.

3. The current sharing circuit according to claim 1, characterized in that: A resistor of the same type is connected in parallel to the resistor RM1.

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