Power supply circuit for power management system

Abstract

The utility model discloses a power supply circuit for a power management system, and relates to the technical field of power supply circuits. The circuit specifically comprises a micro-control unit, wherein a pre-stage driver of the micro-control unit is connected with a switching voltage stabilizing circuit which can generate preset voltage to supply power to a core of the micro-control unit; and the test interface of the micro-control unit is connected with a time delay circuit for supplying power to the test interface after the power supply of the kernel is completed. On the premise that DCDC and LDO are used, it is guaranteed that an MCU can be successfully started and stably run even under the condition of frequent power-on and power-off.

Description

Technical Field

[0001] The utility model relates to the technical field of power supply circuits, in particular to a power supply circuit for a power supply management system. Background Art

[0002] The Battery Management System (BMS) plays an indispensable role in the energy management system of electric vehicles and other battery-driven devices. It is responsible for monitoring the status of the battery pack, including charge and discharge control, voltage and temperature monitoring, and balancing to improve the service life and safety of the battery pack. In this context, the stability and reliability of the BMS are crucial to the entire system.

[0003] In the prior art, the microcontroller unit (MCU) is the core controller of the BMS. Its stable startup and operation are the prerequisites for ensuring the normal operation of the entire BMS system. The MCU needs a stable power supply system to power its core to ensure its normal startup and operation. Usually, the system core power supply comes from a special power supply chip, such as a single-chip onboard power controller (System Basis Chip, SBC).

[0004] In current practice, due to cost considerations, the SBC integrated chip in the BMS power supply solution is replaced with a discrete DCDC+LDO solution. This change brings a series of problems, especially when the BMS needs to power on and off frequently. Since the DCDC+LDO solution is not designed to provide an independent 1.09V output specifically for the MCU core power supply, the reliability of the MCU core power supply is affected.

[0005] In order to solve the above technical problems, in the discrete DCDC+LDO solution, 3.3V is used for power supply, and the PGATE and NGATE inside the MCU are turned on alternately to generate 1.09V to power the MCU core, forming the MCU's own power supply method. Such a design has certain risks in stability, especially during power on and off.

[0006] However, when the BMS performs power-on and power-off operations, if the power-on timing of the MCU's test reset signal (Test Reset, TRST) is earlier than the 3.3V power supply, this timing mismatch will cause the 1.09V voltage required by the core to fail to be established smoothly. Under normal circumstances, the MCU produces the required 1.09V core power supply from 3.3V by alternately turning on PGATE and NGATE. However, if the 3.3V power supply is established later than the TRST signal, the voltage conversion inside the MCU will not be completed, and the MCU will fail to start successfully, which will eventually cause the entire BMS system to fail to work properly.

[0007] Therefore, under the premise of using DCDC and LDO, how to ensure that the MCU can successfully start and run stably even under frequent power on and off conditions has become a technical problem that needs to be solved urgently. Utility Model Content

[0008] The main purpose of the utility model is to provide a power supply circuit for a power management system, aiming to ensure that the MCU can be successfully started and run stably even in the case of frequent power on and off under the premise of using DCDC and LDO.

[0009] In order to achieve the above object, the utility model provides a power supply circuit for a power management system, comprising:

[0010] A microcontroller unit, wherein a switching voltage regulator circuit capable of generating a predetermined voltage to power the core of the microcontroller unit is connected to the front-stage driver of the microcontroller unit; and a delay circuit for powering the test interface after the core is powered is connected to the test interface of the microcontroller unit.

[0011] In one embodiment of the present application, the delay circuit includes:

[0012] Power supply V1, capacitor C1, diode D1, diode D2, transistor Q1, transistor Q2; among them,

[0013] The power supply V1 is connected to the first end of the capacitor C1, the second end of the capacitor C1 is grounded, the anode of the diode D1 is connected between the power supply V1 and the first end of the capacitor C1, the anode of the diode D2 is connected to the cathode of the diode D1, the cathode of the diode D2 is connected to the base of the transistor Q1, the emitter of the transistor Q1 is grounded, the collector of the transistor Q1 is connected to the base of the transistor Q2, the emitter of the transistor Q2 is connected to the power supply V1, and the collector of the transistor Q2 is connected to the test interface of the micro control unit.

[0014] In one embodiment of the present application, the delay circuit further includes:

[0015] The resistor R1 has a first end connected to a power source, a second end connected to a first end of the capacitor, and an anode of the diode D1 connected between the second end of the resistor R1 and the first end of the capacitor C1.

[0016] In one embodiment of the present application, the delay circuit further includes:

[0017] The resistor R2 has a first end connected to the cathode of the diode D2 and a second end connected to the base of the transistor Q1.

[0018] In one embodiment of the present application, the delay circuit further includes:

[0019] The resistor R3 has a first end connected to the collector of the transistor Q2 and a second end connected to the test interface of the micro control unit.

[0020] In one embodiment of the present application, the switching voltage stabilizing circuit includes:

[0021] Power supply V2, MOS tube M1, MOS tube M2, capacitor C4, capacitor C5, inductor L1; wherein, the power supply interface of the micro control unit is connected to the power supply V2, the first end of the MOS tube M1 is connected to the power supply V2, the second end of the MOS tube M1 is connected to the front-stage driver, the third end of the MOS tube M1 is connected to the first end of the MOS tube M2, the second end of the MOS tube M2 is connected to the front-stage driver, the third end of the MOS tube M2 is grounded, the first end of the inductor L1 is connected between the third end of the MOS tube M1 and the first end of the MOS tube M2, the second end of the inductor L1 is respectively connected to the first ends of the capacitor C4 and the capacitor C5, the second ends of the capacitor C4 and the capacitor C5 are both grounded, and the second end of the inductor L1 is connected to the core of the micro control unit and supplies power to the core of the micro control unit.

[0022] In one embodiment of the present application, the power source V1 is 3.3V.

[0023] In one embodiment of the present application, the power source V2 is 3.3V.

[0024] In an embodiment of the present application, the voltage outputted from the second end of the inductor is 1.09V.

[0025] By adopting the above technical solution, the core of the MCU can obtain a stable voltage supply through the preset pre-driver and switch voltage regulator circuit, which is conducive to improving work efficiency and system stability. The addition of a delay circuit ensures that the test interface is powered only after the core power supply is stable, which can avoid interference with the test results due to unstable power supply when the system is just started. Under the premise of using DCDC and LDO, it is guaranteed that the MCU can be successfully started and run stably even in the case of frequent power on and off. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention is described in detail below with reference to specific embodiments and accompanying drawings, wherein:

[0027] Figure 1 This is a schematic structural diagram of the first embodiment of the utility model;

[0028] 10. Switching voltage regulator circuit; 20. Delay circuit. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the utility model clearer, the utility model is described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the following specific embodiments are only used to explain the utility model and do not constitute a limitation on the utility model.

[0030] like Figure 1 As shown, in order to achieve the above-mentioned purpose, the utility model proposes a power supply circuit for a power management system, comprising:

[0031] A microcontroller unit, wherein a switching voltage regulator circuit 10 is connected to the front-stage driver of the microcontroller unit and can generate a predetermined voltage to power the core of the microcontroller unit; a delay circuit 20 is connected to the test interface of the microcontroller unit and powers the test interface after the core is powered on.

[0032] Specifically, the microcontroller unit (MCU) includes a core processing module, which is responsible for executing program code and processing data. The pre-driver is connected between the microcontroller unit and the switching voltage regulator circuit 10. The function of the pre-driver is to adjust the voltage generated by the switching voltage regulator circuit 10 to a level suitable for the MCU core power supply.

[0033] The switching voltage regulator circuit 10 is composed of an inductor and a capacitor, and can convert the external power supply into the voltage required by the MCU core. After the core is powered, in order to ensure that the test interface can get power at the appropriate time, a delay circuit 20 is set. This delay circuit 20 can be a circuit including an RC delay element or a digital timer, or a delay circuit 20 composed of a capacitor and a triode. The delay circuit 20 is used to activate and provide power to the test interface after the main core is stably powered for a period of time.

[0034] By adopting the above technical solution, the core of the MCU can obtain a stable voltage supply through the preset pre-driver and the switching voltage regulator circuit 10, which is conducive to improving work efficiency and system stability. The delay circuit 20 is added to ensure that the test interface is powered only after the core power supply is stable, so that the test results are not disturbed by unstable power supply when the system is just started. Under the premise of using DCDC and LDO, it is guaranteed that the MCU can be successfully started and run stably even in the case of frequent power on and off.

[0035] In one embodiment of the present application, the delay circuit 20 includes:

[0036] Power supply V1, capacitor C1, diode D1, diode D2, transistor Q1, transistor Q2; among them,

[0037] The power supply V1 is connected to the first end of the capacitor C1, the second end of the capacitor C1 is grounded, the anode of the diode D1 is connected between the power supply V1 and the first end of the capacitor C1, the anode of the diode D2 is connected to the cathode of the diode D1, the cathode of the diode D2 is connected to the base of the transistor Q1, the emitter of the transistor Q1 is grounded, the collector of the transistor Q1 is connected to the base of the transistor Q2, the emitter of the transistor Q2 is connected to the power supply V1, and the collector of the transistor Q2 is connected to the test interface of the micro control unit.

[0038] Specifically, the power supply V1 is the energy source of the entire delay circuit 20, providing the necessary voltage supply. The capacitor C1 is connected between the power supply V1 and the ground, and plays the role of delay. When the circuit is powered on, the capacitor C1 starts to charge, and its charging time depends on the size of the capacitor. Due to the presence of diodes D1 and D2, there is a certain voltage drop when it is turned on. Therefore, the transistor Q1 can only be turned on when the voltage at the first end of the capacitor C1 reaches a predetermined condition. The base of the transistor Q1 is connected to the power supply V1 through the diode D2, and the emitter is grounded, which plays the role of a switch. After the base voltage reaches a certain threshold, Q1 is turned on so that a low-resistance path is formed between its collector and emitter, thereby driving Q2. The base of the transistor Q2 is connected through the collector of the transistor Q1, and the emitter is connected to the power supply V1, which plays the role of a switch. The conduction state of the transistor Q2 is controlled by Q1. When Q2 is turned on, its collector provides current to the test interface of the micro control unit, so that the test interface power supply is powered.

[0039] With the above technical solution, the RC delay unit (capacitor C1 and related resistive components) in the circuit design ensures that when the power supply V1 is just powered on, the test interface of the microcontroller is powered after a delay of a period of time, allowing the core of the microcontroller to run stably before testing, ensuring the accuracy of the test. Using basic components and simple connections, it is easy to implement and maintain. Such a design reduces complexity and cost while ensuring the realization of the required functions.

[0040] In one embodiment of the present application, the delay circuit 20 further includes:

[0041] The resistor R1 has a first end connected to a power source, a second end connected to a first end of the capacitor, and an anode of the diode D1 connected between the second end of the resistor R1 and the first end of the capacitor C1.

[0042] Specifically, the first end of the resistor R1 is connected to the power source V1, and the second end is connected to the first end of the capacitor C1. The resistor R1 plays a current limiting role in the circuit, controlling the charging speed of the capacitor C1, thereby affecting the delay period of the entire delay circuit 20. Adding R1 can protect the circuit and prevent the capacitor C1 from being damaged due to excessive current when charging.

[0043] The capacitor C1 and the resistor R1 together form an RC delay element, and the charging and discharging time of the capacitor determines the delay length of the entire delay circuit 20. The second end of the capacitor C1 is grounded to form a complete charging and discharging loop.

[0044] By adopting the above technical solution, the length of the delay can be easily adjusted by changing the value of the resistor R1 or the capacitor C1. This flexibility allows the circuit to be suitable for different delay requirements. The use of resistor R1 to limit the charging current, coupled with the configuration of capacitor C1 and diode D1, can ensure that the delay effect of the circuit is stable and reliable. At the same time, this design reduces the risk of damage to the capacitor or other components caused by sudden current.

[0045] In one embodiment of the present application, the delay circuit 20 further includes:

[0046] The resistor R2 has a first end connected to the cathode of the diode D2 and a second end connected to the base of the transistor Q1.

[0047] Specifically, the resistor R2 is located between the cathode of the diode D2 and the base of the transistor Q1. The main function of R2 is to provide a bias voltage for the base of the transistor Q1, and to control the conduction degree of Q1 by adjusting the resistance value of R2, thereby affecting the signal transmission strength from Q1 to Q2.

[0048] By adopting the above technical solution, the circuit has a more precise control over the base current of the transistor Q1 through the addition of resistor R2, allowing a more detailed adjustment of the delay response, and enhancing the flexibility and accuracy of the circuit adjustment. At the same time, resistor R2 can not only provide a suitable bias current for Q1, but also limit the excessive current flowing into the base, which plays a certain protective role for the transistor Q1 and prolongs the service life of the transistor.

[0049] In one embodiment of the present application, the delay circuit 20 further includes:

[0050] The resistor R3 has a first end connected to the collector of the transistor Q2 and a second end connected to the test interface of the micro control unit.

[0051] Specifically, the resistor R3 is connected between the collector of the transistor Q2 and the test interface of the micro control unit. The function of R3 is to provide a current limit for the test interface of the micro control unit after Q2 is turned on, and also to stabilize the output voltage.

[0052] By adopting the above technical solution, R3 acts as a current limiting resistor, which can limit the maximum current of the micro control unit test interface and prevent the test interface of the micro control unit from being damaged by a sharp change of current.

[0053] In one embodiment of the present application, the switching voltage regulator circuit 10 includes:

[0054] Power supply V2, MOS tube M1, MOS tube M2, capacitor C4, capacitor C5, inductor L1; wherein, the power supply interface of the micro control unit is connected to the power supply V2, the first end of the MOS tube M1 is connected to the power supply V2, the second end of the MOS tube M1 is connected to the front-stage driver, the third end of the MOS tube M1 is connected to the first end of the MOS tube M2, the second end of the MOS tube M2 is connected to the front-stage driver, the third end of the MOS tube M2 is grounded, the first end of the inductor L1 is connected between the third end of the MOS tube M1 and the first end of the MOS tube M2, the second end of the inductor L1 is respectively connected to the first ends of the capacitor C4 and the capacitor C5, the second ends of the capacitor C4 and the capacitor C5 are both grounded, and the second end of the inductor L1 is connected to the core of the micro control unit and supplies power to the core of the micro control unit.

[0055] Specifically, the power source V2 serves as the power supply of the circuit, providing the required power to the components in the system.

[0056] MOS tube M1 and MOS tube M2 are used as switching elements, and work alternately under the control of PWM signal. The first end of MOS tube M1 is connected to power supply V2, the second end is connected to the pre-stage driver, and the third end is connected to the first end of MOS tube M2. The second end of MOS tube M2 is connected to another pre-stage driver, and the third end is grounded to form a closed loop of the circuit.

[0057] Capacitors C4 and C5, as well as inductor L1, form a charging and discharging loop under the control of MOS transistors M1 and M2. The first end of inductor L1 is located between MOS transistors M1 and M2, and the second end is connected to capacitors C4 and C5, and the other ends of capacitors C4 and C5 are grounded.

[0058] The power interface of the micro control unit is directly connected to the power source V2 to obtain power input. The second end of the inductor L1 is directly connected to the core of the micro control unit to provide a stable power supply for it.

[0059] By adopting the above technical solution, the PWM signal generated by the pre-stage driver controls the alternating operation of the MOS tube M1 and the MOS tube M2, so that the capacitor and the inductor form a discharge loop, and a predetermined voltage is obtained through PWM modulation. The structure is simple and easy to implement.

[0060] In one embodiment of the present application, the power source V1 is 3.3V.

[0061] In one embodiment of the present application, the power source V2 is 3.3V.

[0062] In an embodiment of the present application, the voltage outputted from the second end of the inductor is 1.09V.

[0063] The above description is only a preferred embodiment of the utility model, and does not limit the patent scope of the utility model. All equivalent structural changes made by using the contents of the utility model specification and drawings under the utility model concept, or directly / indirectly used in other related technical fields are included in the patent protection scope of the utility model.

Claims

1. A power supply circuit for a power management system, characterized in that: include: A microcontroller unit, wherein a front-stage driver of the microcontroller unit is connected to a switching voltage regulator circuit capable of generating a predetermined voltage to supply power to a core of the microcontroller unit; The test interface of the micro control unit is connected to a delay circuit for supplying power to the test interface after the core is powered on.

2. The power supply circuit for a power management system according to claim 1, characterized in that: The delay circuit comprises: Power supply V1, capacitor C1, diode D1, diode D2, transistor Q1, transistor Q2; among them, The power supply V1 is connected to the first end of the capacitor C1, the second end of the capacitor C1 is grounded, the anode of the diode D1 is connected between the power supply V1 and the first end of the capacitor C1, the anode of the diode D2 is connected to the cathode of the diode D1, the cathode of the diode D2 is connected to the base of the transistor Q1, the emitter of the transistor Q1 is grounded, the collector of the transistor Q1 is connected to the base of the transistor Q2, the emitter of the transistor Q2 is connected to the power supply V1, and the collector of the transistor Q2 is connected to the test interface of the micro control unit.

3. The power supply circuit for a power management system according to claim 2, characterized in that: The delay circuit also includes: The resistor R1 has a first end connected to a power source, a second end connected to a first end of the capacitor, and an anode of the diode D1 connected between the second end of the resistor R1 and the first end of the capacitor C1.

4. The power supply circuit for a power management system according to claim 2 or 3, characterized in that: The delay circuit also includes: The resistor R2 has a first end connected to the cathode of the diode D2 and a second end connected to the base of the transistor Q1.

5. The power supply circuit for a power management system according to claim 4, characterized in that: The delay circuit also includes: The resistor R3 has a first end connected to the collector of the transistor Q2 and a second end connected to the test interface of the micro control unit.

6. The power supply circuit for a power management system according to claim 1, characterized in that: The switching voltage stabilizing circuit comprises: Power supply V2, MOS tube M1, MOS tube M2, capacitor C4, capacitor C5, inductor L1; wherein, the power supply interface of the micro control unit is connected to the power supply V2, the first end of the MOS tube M1 is connected to the power supply V2, the second end of the MOS tube M1 is connected to the front-stage driver, the third end of the MOS tube M1 is connected to the first end of the MOS tube M2, the second end of the MOS tube M2 is connected to the front-stage driver, the third end of the MOS tube M2 is grounded, the first end of the inductor L1 is connected between the third end of the MOS tube M1 and the first end of the MOS tube M2, the second end of the inductor L1 is respectively connected to the first ends of the capacitor C4 and the capacitor C5, the second ends of the capacitor C4 and the capacitor C5 are both grounded, and the second end of the inductor L1 is connected to the core of the micro control unit and supplies power to the core of the micro control unit.

7. The power supply circuit for a power management system according to claim 2, characterized in that: The power supply V1 is 3.3V.

8. The power supply circuit for a power management system according to claim 6, characterized in that: The power supply V2 is 3.3V.

9. The power supply circuit for a power management system according to claim 6, characterized in that: The voltage outputted from the second end of the inductor is 1.09V.

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