Parallel circuit of redundant power supplies

Abstract

The present invention provides a parallel circuit of redundant power supplies. The circuit includes: a plurality of power supply boards and a power supply rail, and the plurality of power supply boards are connected in parallel; wherein, each power supply board includes a power supply module, a PMOS transistor assembly and a control chip; the PMOS transistor assembly includes two PMOS transistors, and the two PMOS transistors are connected in reverse series; the power supply module is connected in series with the PMOS transistor assembly, and the PMOS transistor assembly is connected to the power supply rail; the VIN pin of the control chip is connected to the output end of the power supply module; the SENSE pin of the control chip is connected to the output end of the PMOS transistor assembly; the GATE pin of the control chip is connected to the gates of the two PMOS transistors; the control chip is configured to control the GATE pin to be pulled high to turn off the two PMOS transistors when the difference between the voltage on the SENSE pin and the voltage on the VIN pin is greater than a first preset value. The present invention has low power consumption, reduces line loss, and does not require additional heat sinks.

Description

Technical Field

[0001] The present invention relates to the technical field of redundant power supplies, and in particular to a parallel circuit of redundant power supplies. Background Art

[0002] In the field of rail transit, there are a large number of highly reliable systems that require long-term uninterrupted operation, such as on-vehicle control systems, ground control systems, etc. These systems all require a highly reliable power supply. Redundant power supply design is a key part of them. A redundant power supply means that there are multiple power supplies in the system that supply power to the system simultaneously. When one of the power supplies fails, the other power supplies still work normally to ensure that the power supply of the control system is not affected by the faulty power supply.

[0003] Traditional redundant power supply solutions include power cold backup and parallel redundancy, etc. Cold backup redundancy means that when one of the power supplies fails, the backup power supply starts immediately. In this way, there is a switching interval during power supply switching, and the system power rail is prone to have gaps, so it is not suitable for on-vehicle control systems. The parallel redundancy method means that the power supply system is composed of multiple identical power module outputs connected in parallel. When one of the power supplies fails, it will not affect the power supply system.

[0004] A general parallel redundancy solution is that two or more power supplies are connected in parallel after passing through diodes, as Figure 1 shown. In this way, each power supply can work independently, and when one of the power supplies fails, due to the reverse cut-off characteristic of the diode, the failure of one of the power supplies will not affect the entire power supply system. This solution has the advantages of economy and simple structure.

[0005] However, there is a forward voltage drop in the diode during operation, so that in a situation like an on-vehicle control system where the current is often dozens of amperes, the self-power consumption of only a single diode can reach several watts or even more than ten watts. Such a large power consumption adds difficulty to the thermal design of the system. Therefore, this traditional solution is more suitable for applications with small current and high voltage, and is not suitable for on-vehicle control systems. Summary of the Invention

[0006] The present invention provides a parallel circuit of redundant power supplies to solve the defects in the prior art that the power loss of the diode in the parallel circuit of redundant power supplies is too large, heat dissipation is difficult, and it is not suitable for on-vehicle control systems, and to realize a parallel circuit of redundant power supplies with low power consumption.

[0007] The present invention provides a parallel circuit of redundant power supplies, including:

[0008] Multiple power boards and a power rail, the multiple power boards are connected in parallel;

[0009] Wherein, each power board includes a power module, a PMOS transistor assembly, and a control chip;

[0010] The PMOS transistor assembly includes two PMOS transistors, which are connected in reverse series with each other;

[0011] The power supply module is connected in series with the PMOS transistor assembly, and the PMOS transistor assembly is connected to the power supply rail;

[0012] The VIN pin of the control chip is connected to the output terminal of the power supply module;

[0013] The SENSE pin of the control chip is connected to the output terminal of the PMOS transistor assembly;

[0014] The GATE pin of the control chip is connected to the gates of the two PMOS transistors;

[0015] The control chip is configured to control the GATE pin to be pulled high to turn off the two PMOS transistors when the difference between the voltage on the SENSE pin and the voltage on the VIN pin is greater than a first preset value.

[0016] According to a parallel circuit of redundant power supplies provided by the present invention, each power supply board further includes an MCU, and the CTL pin of the control chip is connected to the MCU.

[0017] According to a parallel circuit of redundant power supplies provided by the present invention, each power supply board further includes a monitoring circuit;

[0018] The monitoring circuit is configured to monitor the output voltage of the power supply module, and send the output voltage to the MCU when the output voltage is not within the preset voltage range of the power supply rail;

[0019] The MCU is configured to send a high-level signal to the CTL pin according to the output voltage;

[0020] The control chip is configured to control the GATE pin to be pulled high according to the high-level signal to turn off the two PMOS transistors.

[0021] According to a parallel circuit of redundant power supplies provided by the present invention, it further includes an operation management board;

[0022] The STATUS pin of the control chip is connected to the MCU;

[0023] The control chip is configured to send a second low-level signal to the MCU through the STATUS pin after controlling the GATE pin to be pulled high;

[0024] The MCU is used to send the status of the power supply board corresponding to the second low-level signal to the operation management board for storage, so that the user can perform fault analysis on the power supply board according to the status of the power supply board in the operation management board.

[0025] According to a parallel circuit of redundant power supplies provided by the present invention, the MCU is used to send a first low-level signal to the CTL pin;

[0026] The control chip is used to control the power supply board to start working according to the first low-level signal.

[0027] According to a parallel circuit of redundant power supplies provided by the present invention, after the power supply board starts working, when the difference between the voltage on the SENSE pin and the voltage on the VIN pin is less than a second preset value, the control chip is used to pull down the GATE pin to turn on the two PMOS transistors.

[0028] According to a parallel circuit of redundant power supplies provided by the present invention, when the part where the voltage on the VIN pin of the control chip is less than the voltage on the VIN pin of the control chip in any other power supply board is greater than 0 and less than a third threshold, the control chip is used to adjust the voltage of the gates of the two PMOS transistors connected to the GATE pin through the GATE pin of the control chip, so that the voltage on the VIN pin of the control chip is the same as the voltage on the VIN pin of the control chip in any other power supply board.

[0029] According to a parallel circuit of redundant power supplies provided by the present invention, when the part where the voltage on the VIN pin of the control chip is less than the voltage on the VIN pin of the control chip in any other power supply board is greater than the third threshold, the control chip is used to pull up the GATE pin to turn off the two PMOS transistors.

[0030] In the parallel circuit of redundant power supplies provided by the present invention, by using PMOS transistors to replace the diodes in the traditional solution, the on-resistance of the PMOS transistors is relatively small, only a few mΩ, which greatly reduces the loss of the transistors, so that there is no need to install a radiator in the circuit design, simplifies the thermal design, and at the same time greatly improves the efficiency of the circuit for high-current applications; the control chip controls the PMOS transistors to achieve the power supply switching effect of the diodes, thereby realizing the efficient wired-OR operation of multiple power modules. Brief Description of the Drawings

[0031] To more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0032] Figure 1 is the parallel circuit diagram of the redundant power supplies provided by the prior art;

[0033] Figure 2 is the parallel circuit diagram of the redundant power supplies provided by the present invention. Detailed Embodiments

[0034] To make the objectives, technical solutions and advantages of the present invention clearer, the following clearly and completely describes the technical solutions in the present invention with reference to the drawings in the present invention. Obviously, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0035] The following combines Figure 2 to describe a parallel circuit of redundant power supplies of the present invention, which includes a plurality of power supply boards and power rails, and the plurality of power supply boards are connected in parallel;

[0036] Figure 2 includes two power supply boards, namely Power Supply Board I and Power Supply Board II, and the two power supply boards jointly supply power to the power rail. This embodiment is not limited to the number of power supply boards.

[0037] The plurality of power supply boards are connected in parallel to the power rail and are connected in parallel to form a wired-OR logic to jointly supply power to the load.

[0038] Among them, each power supply board includes a power module, a PMOS transistor assembly and a control chip;

[0039] The power module is a module for power supply. The PMOS transistor assembly is an assembly containing P-type MOSFET (Metal Oxide Semiconductor Field Effect Transistor) transistors.

[0040] Optionally, the control chip adopts an LTC4414 chip.

[0041] The PMOS transistor assembly includes two PMOS transistors, and the two PMOS transistors are connected in series in reverse;

[0042] For a PMOS transistor, the current flows from the source to the drain, and when the gate is pulled low, the transistor conducts. Due to the existence of parasitic diodes, if a single MOS transistor is used, LTC4414 cannot turn off the power output through the MOS transistor. Therefore, two MOS transistors need to be connected back-to-back, that is, connected in reverse series, as Figure 2 shown.

[0043] It is connected in series between the power supply module and the PMOS transistor assembly, and the PMOS transistor assembly is connected to the power supply rail;

[0044] Each power supply module in the power supply board is connected in series with the PMOS transistor assembly, and the electrical energy provided by the power supply module enters the power supply rail through the PMOS transistor assembly.

[0045] The VIN (Voltage Input) pin of the control chip is connected to the output terminal of the power supply module;

[0046] The VIN of the control chip is used to monitor the output voltage of the power supply module in this power supply board.

[0047] The SENSE pin of the control chip is connected to the output terminal of the PMOS transistor assembly;

[0048] The SENSE pin of the control chip is used to monitor the voltage of the power supply rail connected to the PMOS transistor assembly in this power supply board.

[0049] The GATE pin of the control chip is connected to the gates of the two PMOS transistors;

[0050] The control chip is used to control the GATE pin to be pulled high when the difference between the voltage on the SENSE pin and the voltage on the VIN pin is greater than the first preset value, so as to turn off the two PMOS transistors.

[0051] Due to process limitations, the characteristics and parameters of power supply modules cannot be exactly the same, resulting in different output characteristics of power supply modules. When multiple power supply modules with different output characteristics are connected in parallel for output, there will be current circulation, and some power supplies will even become the loads of other power supplies.

[0052] The control chip compares the output voltage of the power supply module in this power supply board with the voltage of the power supply rail connected to the PMOS transistor assembly in this power supply board. When the value by which the voltage of the power supply rail is higher than the output voltage of the power supply module is large, the GATE pin of the control chip will be automatically pulled high by the control chip, thereby completely turning off the power output path of this power supply board and preventing the occurrence of current circulation phenomenon.

[0053] In this embodiment, a PMOS transistor is used to replace the diode in the traditional solution. The on-resistance of the PMOS transistor is relatively small, only a few mΩ, which greatly reduces the loss of the transistor, enabling the elimination of the need for a heat sink in circuit design, simplifying the thermal design. At the same time, for high-current applications, the circuit efficiency is also significantly improved; the control chip controls the PMOS transistor to achieve the power switching effect of the diode, thereby realizing the high-efficiency wired-OR operation of multiple power modules.

[0054] Based on the above embodiment, in this embodiment, each power board further includes an MCU (Microcontroller Unit), and the CTL pin of the control chip is connected to the MCU.

[0055] Specifically, the MCU in each power board sends a level signal to the control chip in the same power board through the CTL pin of the control chip in the same power board.

[0056] Based on the above embodiment, in this embodiment, each power board further includes a monitoring circuit; the monitoring circuit is used to monitor the output voltage of the power module, and when the output voltage is not within the preset voltage range of the power rail, send the output voltage to the MCU;

[0057] The monitoring circuit in the power board monitors whether the output voltage of the power module in the same power board is within the preset voltage range, that is, the normal voltage range.

[0058] The MCU is used to send a high-level signal to the CTL pin according to the output voltage;

[0059] When the output voltage of the power module is not within the normal voltage range, the power module is likely to be short-circuited, and the MCU sends a high-level signal to the CTL pin of the control chip in the same power board.

[0060] The control chip is used to control the GATE pin to be pulled high according to the high-level signal, so as to turn off the two PMOS transistors.

[0061] The control chip cuts off the connection between the source and drain of each PMOS transistor in the same power board by pulling high the GATE pin, thereby cutting off the power output of the same power board to ensure the normal operation of the power rail.

[0062] For example, when the power module in Power Board I is short-circuited, due to the short-circuit protection circuit inside, it will directly cause no output from this power module. Power Board II still works normally, so the power system still remains normal. Although Power Board I is short-circuited, due to the back-to-back connection of the dual PMOS transistors, it forms an open circuit between Power Board I and the power rail, so it will not affect the external power supply of the entire power system.

[0063] On the basis of the above embodiments, a running management board is further included in this embodiment; the STATUS pin of the control chip is connected to the MCU;

[0064] The control chip is configured to send a second low-level signal to the MCU through the STATUS pin after pulling up the GATE pin;

[0065] When the control chip cuts off the output path of this power supply board by pulling up its own GATE pin, it sends a low-level signal to the MCU through its own STATUS pin.

[0066] The MCU is configured to send the status of the power supply board corresponding to the second low-level signal to the running management board for storage, so that the user can perform fault analysis on the power supply board according to the status of the power supply board in the running management board.

[0067] The status of the power supply board is that the output path is cut off.

[0068] The control part in this embodiment can monitor the output status of the power supply board in real time and can control the output of the power supply according to the application, and is applicable to occasions with high requirements for the reliability of the system power supply.

[0069] On the basis of each of the above embodiments, in this embodiment, the MCU is configured to send a first low-level signal to the CTL pin; the control chip is configured to control the power supply board to start working according to the first low-level signal.

[0070] Specifically, after all the power supply boards in the power supply system are powered on, the MCU on each power supply board will send a low-level signal to the CTL pin of the control chip, and each power supply board starts to work.

[0071] On the basis of the above embodiments, in this embodiment, the control chip is configured to, after the power supply board starts to work, when the difference between the voltage on the SENSE pin and the voltage on the VIN pin is less than a second preset value, control the GATE pin to be pulled low so that the two PMOS transistors are turned on.

[0072] Specifically, after all the power supply boards start to work, if the difference between the voltage on the SENSE pin and the voltage on the VIN pin of the control chip on each power supply board is less than a second preset value, such as -20 mV, the GATE pin of this control chip will be pulled low, and then the source and drain of each external back-to-back PMOS transistor will be turned on, and the power supply module will output power to the outside.

[0073] Based on the above embodiments, in this embodiment, the control chip is configured to, when the voltage on the VIN pin of the control chip is less than the voltage on the VIN pin of the control chip in any other power supply board, and the part greater than 0 and less than the third threshold, adjust the voltage of the gates of the two PMOS transistors connected to the GATE pin through the GATE pin of the control chip, so that the voltage on the VIN pin of the control chip is the same as the voltage on the VIN pin of the control chip in any other power supply board.

[0074] The control chip in this embodiment monitors the output voltage of the power module in this power supply board in real time. When the output voltages of the power modules in any two power supply boards are different and the difference between them is small, the control chip on the power supply board with the lower output voltage among the two power supply boards will adjust the voltage on its own VIN pin to adjust the conduction state of the PMOS transistor connected to its own VIN pin, making its conduction impedance smaller, so that the voltage it outputs remains consistent with that of the other power supply board, thus achieving the consistent output of multiple power supply boards.

[0075] Based on the above embodiments, in this embodiment, the control chip is configured to, when the part of the voltage on the VIN pin of the control chip that is less than the voltage on the VIN pin of the control chip in any other power supply board is greater than the third threshold, control the GATE pin to be pulled high to turn off the two PMOS transistors.

[0076] Specifically, when the output voltages of the power modules in any two power supply boards are different and the difference between them is large, the control chip automatically cuts off the power output path of this power supply board by controlling the GATE pin to be pulled high.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A parallel circuit of redundant power supplies, characterized in that, It includes multiple power supply boards and power rails, and the multiple power supply boards are connected in parallel; Among them, each power supply board includes a power supply module, a PMOS transistor assembly and a control chip; The PMOS transistor assembly includes two PMOS transistors, and the two PMOS transistors are connected in series in reverse; The power supply module is connected in series with the PMOS transistor assembly, and the PMOS transistor assembly is connected to the power rail; The VIN pin of the control chip is connected to the output end of the power supply module; The SENSE pin of the control chip is connected to the output end of the PMOS transistor assembly; The GATE pin of the control chip is connected to the gates of the two PMOS transistors; The control chip is used to control the GATE pin to be pulled high to turn off the two PMOS transistors when the difference between the voltage on the SENSE pin and the voltage on the VIN pin is greater than a first preset value; Each power supply board further includes an MCU and a monitoring circuit. The CTL pin of the control chip is connected to the MCU; the monitoring circuit is used to monitor the output voltage of the power supply module and send the output voltage to the MCU when the output voltage is not within the preset voltage range of the power rail; the MCU is used to send a high-level signal to the CTL pin according to the output voltage; the control chip is used to control the GATE pin to be pulled high to turn off the two PMOS transistors according to the high-level signal; The control chip is used to adjust the voltage of the gates of the two PMOS transistors connected to the GATE pin through the GATE pin of the control chip when the part where the voltage on the VIN pin of the control chip is less than the voltage on the VIN pin of the control chip in any other power supply board is greater than 0 and less than a third threshold, so that the voltage on the VIN pin of the control chip is the same as the voltage on the VIN pin of the control chip in any other power supply board; The control chip is used to control the GATE pin to be pulled high to turn off the two PMOS transistors when the part where the voltage on the VIN pin of the control chip is less than the voltage on the VIN pin of the control chip in any other power supply board is greater than the third threshold.

2. The parallel circuit of redundant power supplies according to claim 1, wherein It further includes an operation management board; The STATUS pin of the control chip is connected to the MCU; The control chip is used to send a second low-level signal to the MCU through the STATUS pin after controlling the GATE pin to be pulled high; The MCU is used to send the status of the power supply board corresponding to the second low-level signal to the operation management board for storage, so that the user can perform fault analysis on the power supply board according to the status of the power supply board in the operation management board.

3. The parallel circuit of redundant power supplies according to any one of claims 1-2, characterized in that, The MCU is used to send a first low-level signal to the CTL pin; The control chip is used to control the power supply board to start working according to the first low-level signal.

4. The parallel circuit of redundant power supplies according to claim 3, characterized in that, The control chip is used to control the GATE pin to be pulled low after the power supply board starts to work, so that the two PMOS transistors are turned on when the difference between the voltage on the SENSE pin and the voltage on the VIN pin is less than a second preset value.

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