Power supply parallel operation current-sharing output device

Abstract

The invention discloses a power supply parallel operation current-sharing output device, which comprises a plurality of channels, power supply modules in each channel perform parallel operation output, and each channel comprises a power converter module, a current sampling module, a maximum value module, a subtraction circuit module, a compensation adjustment module, a feedback module, a following module and a switch and anti-reverse module. The circuit is mainly applied to semiconductor aging equipment, is used for parallel operation output of multiple paths of power supplies, and realizes high-precision current-sharing output and overcompensation control.

Description

Technical Field

[0001] The present invention relates to a power supply parallel output device applied to the semiconductor testing industry. Background Art

[0002] When a semiconductor testing device requires a large current, it needs to output in parallel through multiple power supplies. In the existing technology, diodes are relied on for protection of parallel output, and the current sharing effect after parallel connection is not good. It cannot achieve full current sharing (poor accuracy); there is no protection, and if the current reverses, it will cause circuit damage; the limit compensation current sharing value cannot be adjusted. Summary of the Invention

[0003] The purpose of the present invention is to provide a power supply parallel current sharing output device that can make the output currents of each power converter equal.

[0004] The technical solution of the present invention is as follows:

[0005] A power supply parallel current sharing output device includes multiple channels, and the power supply modules in each channel output in parallel. The characteristics are that each channel includes:

[0006] A power converter module for realizing the conversion between the input voltage and the output voltage;

[0007] A current sampling module for measuring the magnitude of the output current of the power converter;

[0008] A maximum value module for collecting the maximum current value;

[0009] A subtraction circuit module, which is a compensation bias circuit, for performing negative bias compensation on the maximum current value and then amplifying and outputting it. Similar to a subtraction circuit, it subtracts an error bias from the collected maximum current value and then outputs it;

[0010] A compensation adjustment module, which is a compensation control circuit;

[0011] A feedback module, which is the output sampling circuit of the converter, for measuring the output voltage of the converter and then amplifying and outputting it. This module also has an isolation function. The input and output use the characteristic of the large input resistance of the operational amplifier to isolate the input and output signals. The purpose of isolation is to reduce the loss of signal transmission;

[0012] A follower module for amplifying the compensated feedback signal and adjusting the output voltage of the power converter;

[0013] A switch and anti-reverse module, which is used for protection and has two protection functions: the first is over-compensation protection, and the other protection is anti-reverse, that is, to prevent current from flowing back into the power converter and causing circuit damage;

[0014] By measuring the output currents of each power converter in multiple channels and extracting the maximum value of the output current in the power converter, after subtracting a bias from this maximum value and then comparing it with the output currents of each power converter, if the output current of a certain power converter is lower than this maximum current, its own feedback circuit will be adjusted to make the self-current equal to it, achieving current sharing.

[0015] The current sampling module includes a sampling resistor R1 and a differential amplifier U4; the first terminal pin of the amplifier U4 is connected to the second terminal of the resistor R4, the third terminal pin of the amplifier U9, and the third terminal pin of the amplifier U6; the second terminal pin of the amplifier U4 is connected to the second terminal of the resistor R2, the second terminal of the resistor R1, and the third terminal of the PMOS U1, and the third terminal pin of the amplifier U4 is connected to the first terminal of the resistor R1 and the output terminal of the power converter.

[0016] The maximum value module includes an amplifier U9. The first terminal pin of the amplifier U9 is connected to the anode of the diode D2, and the cathode of the diode D2 is connected to the third terminal pin of the amplifier U10 and the second terminal pin of the amplifier U9; when the power converters are paralleled and output, the IOs in each power supply module are connected together to collect the maximum value of the output currents of each power converter.

[0017] The subtraction circuit module includes an amplifier U10, and V1 in the module is a compensation value; let the maximum current value be IMAX, the compensation value be IV, and the output be IOUT, then the output current value:

[0018] IOUT = IAMX - IV [Equation 1].

[0019] The compensation adjustment module includes 3 resistors, 1 operational amplifier, 1 triode, and 1 capacitor; the third terminal pin of the operational amplifier U8 is connected to the first terminal pin of the amplifier U10, the second terminal pin of the operational amplifier U8 is connected to the first terminal of the resistor R4 and the second terminal of the capacitor C1, the first terminal of the operational amplifier U8 is connected to the first terminal of the capacitor C1 and the first terminal of the resistor R7, the second terminal of the resistor R7 is connected to the B pole of the triode Q1, the C pole of the triode Q1 is connected to the second terminal of the resistor R5, the E pole of the triode Q1 is connected to the ground, and the first terminal of the resistor R5 is connected to the third terminal pin of the amplifier U5 and the second terminal of the resistor R3.

[0020] The feedback module includes an amplifier U3. The third terminal pin of the amplifier U3 is connected to the first terminal of the resistor R2, and the second terminal pin of the amplifier U3 is connected to the first terminal of the resistor R3 after being connected to the first terminal pin.

[0021] The following module includes an amplifier U5. The third terminal pin of the amplifier U5 is connected to the output terminal of the compensation adjustment module. The second terminal pin of the amplifier U5 is connected to the first terminal pin and then connected to the feedback FB of the power converter module to control the voltage output of the power converter module.

[0022] The switch and reverse protection module includes an amplifier U6. The third terminal pin of the amplifier U6 is connected to the maximum value module. The second terminal pin of the amplifier U6 is connected to the compensation voltage. The first terminal pin of the amplifier U6 is connected to the anode of a diode D1. The cathode of the diode D1 is connected to the first terminal of a resistor R6. The second terminal of the resistor R6 is connected to the first terminal pin of an optocoupler U7. The second terminal pin of the optocoupler U7 is connected to the ground. The third terminal pin of the optocoupler U7 is connected to the negative voltage VCC. The fourth terminal pin of the optocoupler U7 is connected to the GATE of a PMOS U1 and the GATE of a PMOS U2. The second pin of the PMOS U1 is connected to the second pin of the PMOS U2. The third terminal pin of the PMOS U1 is connected to the current sampling module. The third terminal pin of the PMOS U2 is connected to the output VOUT.

[0023] Advantages of the present invention:

[0024] 1. By adopting the current measurement technology, the output currents of each power converter are made equal. In the prior art, the current sharing is achieved by using the unidirectional conductivity of diodes, and the output currents of each power converter are not equal.

[0025] 2. By adopting the control maximum compensation technology, the output currents of each power converter cannot be increased or decreased infinitely when compensating for current sharing. In the prior art, the maximum value current limiting control is achieved by relying on the current limiting function of the power converter itself, which is likely to damage the components of the power converter.

[0026] 3. By adopting the switch and reverse protection combination technology, its function is more stable and reliable, and when an abnormality occurs, the output of the power converter can be turned off. In the prior art, there is only diode reverse protection without a switch function.

[0027] The present invention is mainly applied to semiconductor aging equipment, used for multi-channel power supply parallel output to achieve high-precision current sharing output and over-compensation control. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The present invention will be further described below with reference to the drawings and embodiments.

[0029] Figure 1 It is a schematic diagram of a single-channel structure of an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] A power supply parallel current sharing output device is mainly composed of a plurality of power supply modules. Each power supply module is composed of 8 small modules, such as Figure 1The eight modules shown: 1. Power converter, 2. Current sampling module, 3. Maximum value module, 4. Subtraction circuit module, 5. Compensation adjustment module, 6. Feedback module, 7. Follow-up module, 8. Switch and reverse protection module.

[0031] In the parallel operation of multi-channel power outputs, multiple power modules are paralleled for output. The output current of each power converter is equal, that is, the current sharing output is achieved, and the parallel output of multiple power converters realizes current sharing.

[0032] The present invention consists of multiple channels, but only the first channel is described and narrated during the description. Because multiple channels are composed of single channels, and the main implementation methods are the same.

[0033] The power converter module 1 is used to realize the conversion of input voltage and output voltage; it can be a boost circuit or a buck circuit, and the output voltage can be adjusted through the feedback FB.

[0034] The current sampling module 2 is used to measure the magnitude of the output current of the power converter; it includes a sampling resistor R1 and a differential amplifier U4; the first terminal pin of the amplifier U4 is connected to the second terminal of the resistor R4, the third terminal pin of the amplifier U9, and the third terminal pin of the amplifier U6; the second terminal pin of the amplifier U4 is connected to the second terminal of the resistor R2, the second terminal of the resistor R1, and the third terminal of the PMOS U1, and the third terminal pin of the amplifier U4 is connected to the first terminal of the resistor R1 and the output terminal of the power converter.

[0035] The maximum value module 3 is used to collect the maximum current value, including an amplifier U9. The first terminal pin of the amplifier U9 is connected to the anode of the diode D2, and the cathode of the diode D2 is connected to the third terminal pin of the amplifier U10 and the second terminal pin of the amplifier U9; when the power converters are paralleled for output, the IOs in each power module are connected together to collect the maximum value of the output currents of each power converter.

[0036] The subtraction circuit module 4 is a compensation bias circuit, which is used to perform negative bias compensation on the maximum current value and then amplify and output it. It is similar to a subtraction circuit, that is, subtracting an error bias from the collected maximum current value and then outputting it; it includes an amplifier U10, and V1 in the module is a compensation value; assuming the maximum current value is IMAX, the compensation value is IV, and the output is IOUT, then the output current value:

[0037] IOUT = IAMX - IV [Equation 1].

[0038] The compensation adjustment module 5 is a compensation control circuit, including three resistors, one operational amplifier, one triode, and one capacitor. The third pin of the operational amplifier U8 is connected to the first pin of the amplifier U10. The second pin of the operational amplifier U8 is connected to the first end of the resistor R4 and the second end of the capacitor C1. The first pin of the operational amplifier U8 is connected to the first end of the capacitor C1 and the first end of the resistor R7. The second end of the resistor R7 is connected to the B pole of the triode Q1. The C pole of the triode Q1 is connected to the second end of the resistor R5. The E pole of the triode Q1 is connected to the ground. The first end of the resistor R5 is connected to the third pin of the amplifier U5 and the second end of the resistor R3.

[0039] The feedback module 6 is the output sampling circuit of the converter, used to measure the output voltage of the converter, and then output it after amplification. This module also has an isolation function. The input and output use the characteristic of the large input resistance of the operational amplifier to isolate the input and output signals. The purpose of isolation is to reduce the loss of signal transmission. It includes the amplifier U3. The third pin of the amplifier U3 is connected to the first end of the resistor R2. The second pin of the amplifier U3 is connected to the first pin and then connected to the first end of the resistor R3.

[0040] The follower module 7 is used to amplify the compensated feedback signal and adjust the output voltage of the power converter. It includes the amplifier U5. The third pin of the amplifier U5 is connected to the output end of the compensation adjustment module. The second pin of the amplifier U5 is connected to the first pin and then connected to the FB (feedback) of the power converter module to control the voltage output of the power converter module.

[0041] The switch and anti-reverse module 8 is used for protection and has two protection functions: the first is over-compensation protection. For example, the maximum current compensation is 3A. If the compensated current exceeds 3A, then this switch will disconnect to protect the circuit and output an error message. The other protection is anti-reverse, which is to prevent current from flowing back into the power converter and causing circuit damage. It includes the amplifier U6. The third pin of the amplifier U6 is connected to the maximum value module. The second pin of the amplifier U6 is connected to the compensation voltage. The first pin of the amplifier U6 is connected to the anode of the diode D1. The cathode of the diode D1 is connected to the first end of the resistor R6. The second end of the resistor R6 is connected to the first pin of the optocoupler U7. The second pin of the optocoupler U7 is connected to the ground. The third pin of the optocoupler U7 is connected to the negative voltage VCC. The fourth pin of the optocoupler U7 is connected to the GATE of the PMOS U1 and the GATE of the PMOS U2. The second pin of the PMOS U1 is connected to the second pin of the PMOS U2. The third pin of the PMOS U1 is connected to the current sampling module. The third pin of the PMOS U2 is connected to the output VOUT.

[0042] The circuit connections of the entire device: the IO, VOUT, and -VCC of each power supply module are connected together.

[0043] By measuring the output currents of individual power converters in multiple channels and extracting the maximum output current in the power converters, after subtracting a bias from this maximum value, and then comparing it with the output currents of the individual power converters, if the output current of a certain power converter is lower than this maximum current, its own feedback circuit will be adjusted to make the self - current equal to it, thus achieving current sharing.

[0044] Before implementation, multiple power modules need to be connected in parallel. For example, the IOs in the first power module, the second power module, and the nth power module are interconnected. After being connected together, module 3 in each power module can collect the maximum current values output from the n power modules. Current values less than the maximum will be ignored.

[0045] After obtaining the maximum current value from the power modules connected in multiple parallel paths and comparing it with the output currents of each power module, when there is a current value lower than the maximum, the power supply of this path of the module will be adjusted to increase the current output.

[0046] For example: there are 3 power modules connected in parallel for output, the total current is 30A, and the respective output currents of the 3 power converters connected in parallel are I1 = 7A, I2 = 10A, I3 = 13A; there must be errors in the actual circuit, so the allowable current error for each is 1A, that is, V1 = 1A, and the maximum current value IMAX extracted by measurement is 13A.

[0047] At this time, the output current signal value of the maximum - value module 3 is 13A - 1A = 12A; the other two current values 10A / 7A are ignored. That is to say, the difference between the maximum current value and the minimum current value is 1A, and V1 = 1A is determined by actual measurement, and it can be smaller or larger in some devices.

[0048] The maximum - value module 3 extracts a maximum value of 13A. After error compensation by module 4, the output is I = 12A. This 12A is used as the reference of operational amplifier U8 and is connected to the non - inverting terminal. The inverting terminal of U8 is connected to the sampling output terminal of U4. When the current - signal voltage at the inverting terminal is greater than 12A, U8 has no output, indicating that the output current of this module power supply is equal to the maximum, and there is no compensation for this power module. On the contrary, if the current signal at the inverting terminal of U8 is less than 12A, U8 outputs a compensation voltage signal. At this time, there is a voltage at VBE of Q1, and VCE conducts. In this way, the voltage at PIN3 of U5 will be reduced. Let the voltage at PIN3 of U5 be Up, the output voltage be VOUT, and the current between CE in Q1 be ICE;

[0049] Up = VOUT - ICE * R3 [Equation 2]

[0050] According to Equation 2, when there is no input to U8, ICE = 0 and Up = VOUT; when there is compensation and ICE is not equal to 0, the voltage of Up decreases. After this voltage is fed back to the power supply module, the power supply module will increase the output voltage. As the output voltage increases and the resistance value of the output load remains unchanged, the output current increases until the output current is equal to the maximum current. Of course, when the voltage of the first module rises and the current rises, the current of the third module with the maximum current value will decrease and the voltage will decrease because when the third power supply module self-checks and detects the voltage rise, it will actively adjust the voltage to decrease automatically.

[0051] The characteristic of the circuit lies in the R5 resistor, which is used for the maximum current compensation value of the device. (It is mainly achieved through the adjustment of the output voltage).

[0052] When the VCE of Q1 = 0,

[0053] Up = VOUT*R5 / (R3 + R5) [Equation 3]

[0054] It can be obtained from Equation 3 that if R5 = 0, then when VCE = 0, Up = 0, and the compensation value at this time will be infinitely large, damaging the device. This setting is set at 70%. In fact, in some implementations, it can be adjusted and is not fixed.

[0055] Up = 0.7*VOUT = VOUT*R5 / (R3 + R5)

[0056] R5 / (R3 + R5) = 0.7 [Equation 4]

[0057] If the R5 / R3 configuration is configured according to Equation 4, then the configuration ratio is 30%. The lower the configuration ratio, the higher the compensation ratio.

[0058] The diode D2 is used to obtain the maximum current and prevent reverse connection. R4 is a matching resistor for current limiting. C1 is used to prevent the amplifier output from oscillating.

[0059] The switch and the anti-reverse module 8 are used for protection. U6 is connected to module 2 to detect whether there is current reflux. If there is current reflux, U6 outputs a low level, the optocoupler U7 does not work, U1 / U2 is disconnected, and there is no output voltage at VOUT. VT1 is the control voltage. When the voltage of VT1 is high (Vp > Vn), U7 does not work and there is no output at VOUT. When there is no load, Vn = 0V. If the no-load voltage needs to be output, the voltage of VT1 is negative, otherwise Vp = Vn, the amplifier oscillates, and the output voltage is unstable. When an abnormality occurs and the output voltage of VOUT needs to be turned off, the voltage of VT1 is a high level of 3V. U7 is an optocoupler. A negative voltage is connected to the third pin of the secondary of U7 to make U1 / U2 also conduct when VOUT = 0. Because the VGS voltage of the MOS needs to be greater than a certain threshold for the DS of the MOS to conduct. U1 / U2 is a PMOS. The conduction threshold voltage of the PMOS is usually -5V for the DS to be fully conductive. If -VCC = 0V and when VOUT = 0V, then VGS = 0V and U1 / U2 cannot conduct. At this time, only a negative voltage, such as -6V, needs to be applied to the G pole, then VGS = -6V, and at this time the MOS U1 / U2 is fully conductive. This is the function of -VCC.

Claims

1. A power supply parallel operation current sharing output device, including multiple channels, and power supply modules in each channel perform parallel operation and output. The characteristics are as follows: Each channel includes: A power converter module for implementing the conversion of the input voltage and the output voltage; A current sampling module for measuring the magnitude of the output current of the power converter; A maximum value module for collecting the maximum current value; A subtraction circuit module, which is a compensation bias circuit for amplifying and outputting the maximum current value after negative bias compensation. It is similar to a subtraction circuit, that is, subtracting an error bias from the collected maximum current value and then outputting; A compensation adjustment module, which is a compensation control circuit; A feedback module, which is the output sampling circuit of the converter for measuring the output voltage of the converter and then amplifying and outputting. This module also has an isolation function. The input and output use the characteristic of the large input resistance of the operational amplifier to isolate the input and output signals. The purpose of isolation is to reduce the loss of signal transmission; A follower module for amplifying the compensated feedback signal and adjusting the output voltage of the power converter; A switch and reverse protection module, which is used for protection and has two protection functions: the first is over-compensation protection, and the other protection is reverse protection, that is, to prevent current from flowing back into the power converter and causing circuit damage; By measuring the output currents of each power converter in multiple channels and extracting the maximum value of the output current in the power converter, after subtracting a bias from this maximum value, it is then compared with the output currents of each power converter. If the output current of a certain power converter is lower than this maximum current value, its own feedback circuit will be adjusted to make the current equal to it, achieving current sharing.

2. The parallel operation and current sharing output device of a power supply according to claim 1, characterized in that: The current sampling module includes a sampling resistor R1 and a differential amplifier U4; the first terminal pin of the amplifier U4 is connected to the second terminal of the resistor R4, the third terminal pin of the amplifier U9, and the third terminal pin of the amplifier U6; the second terminal pin of the amplifier U4 is connected to the second terminal of the resistor R2, the second terminal of the resistor R1, and the third terminal of the PMOS U1, and the third terminal pin of the amplifier U4 is connected to the first terminal of the resistor R1 and the output terminal of the power converter.

3. A parallel operation current sharing output device for a power supply according to claim 1, wherein: The maximum value module includes an amplifier U9. The first terminal pin of the amplifier U9 is connected to the anode of the diode D2, and the cathode of the diode D2 is connected to the third terminal pin of the amplifier U10 and the second terminal pin of the amplifier U9; when the power converters are paralleled and output, the IOs in each power supply module are connected together to collect the maximum value of the output currents of each power converter.

4. A parallel power supply current-sharing output device according to claim 1, characterized in that: The subtraction circuit module includes an amplifier U10, and V1 in the module is a compensation value; assuming the maximum current value is IMAX, the compensation value is IV, and the output is IOUT, then the output current value: IOUT = IAMX - IV [Equation 1].

5. A power supply parallel operation current sharing output device according to claim 1, characterized in that: The compensation adjustment module includes three resistors, one operational amplifier, one triode, and one capacitor; the third terminal pin of operational amplifier U8 is connected to the first terminal pin of amplifier U10, the second terminal pin of operational amplifier U8 is connected to the first end of resistor R4 and the second end of capacitor C1, the first end of operational amplifier U8 is connected to the first end of capacitor C1 and the first end of resistor R7, the second end of resistor R7 is connected to the B pole of triode Q1, the C pole of triode Q1 is connected to the second end of resistor R5, the E pole of triode Q1 is connected to ground, and the first end of resistor R5 is connected to the third terminal pin of amplifier U5 and the second end of resistor R3.

6. The power supply parallel operation current sharing output device according to claim 1, characterized in that: The feedback module includes amplifier U3. The third terminal pin of amplifier U3 is connected to the first end of resistor R2, and the second terminal pin of amplifier U3 is connected to the first end of resistor R3 after being connected to the first terminal pin.

7. The power supply parallel operation current sharing output device according to claim 1, characterized in that: The follower module includes amplifier U5. The third terminal pin of amplifier U5 is connected to the output end of the compensation adjustment module. The second terminal pin of amplifier U5 is connected to the feedback FB of the power converter module after being connected to the first terminal pin to control the voltage output of the power converter module.

8. A power supply parallel operation current sharing output device according to claim 1, characterized in that: The switch and reverse protection module includes amplifier U6. The third terminal pin of amplifier U6 is connected to the maximum value module. The second terminal pin of amplifier U6 is connected to the compensation voltage. The first terminal pin of amplifier U6 is connected to the anode of diode D1. The cathode of diode D1 is connected to the first end of resistor R6. The second end of resistor R6 is connected to the first terminal pin of optocoupler U7. The second terminal pin of optocoupler U7 is connected to ground. The third terminal pin of optocoupler U7 is connected to the negative voltage VCC. The fourth terminal pin of optocoupler U7 is connected to the GATE of PMOS U1 and the GATE of PMOS U2. The second pin of PMOS U1 is connected to the second pin of PMOS U2. The third terminal pin of PMOS U1 is connected to the current sampling module. The third terminal pin of PMOS U2 is connected to the output VOUT.

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