Wide-range series voltage stabilizing circuit design method

Abstract

The invention belongs to the technical field of electronic circuits, and discloses a wide-range series voltage stabilizing circuit design method, which comprises the following steps: providing a voltage judgment unit for comparing an input voltage with a preset threshold value; a voltage stabilizing unit is provided and used for outputting two different voltage levels according to the comparison result of the voltage judging unit, when the input voltage is larger than a preset threshold value, the voltage stabilizing unit outputs a high voltage level, and when the input voltage is smaller than the preset threshold value, the voltage stabilizing unit outputs a low voltage level. According to the technical scheme of the invention, stable power supply for post-stage BUCK input can be realized, the power supply design is simplified, and the reliability and compatibility of the system are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of electronic circuits, and in particular relates to a design method for a wide-range series voltage-stabilizing circuit. Background Art

[0002] The auxiliary power supply design must be reliable. As the space size limit increases, the power supply design must be simplified. In the low-voltage battery motor controller, the motor braking feedback causes a short-term voltage increase. In order to avoid high-voltage damage, the auxiliary power supply was selected in the early stage, but it was relatively complicated. Recently, the series voltage regulation + BUCK mode has appeared. The series voltage regulation bears the short-term high voltage and provides a stable input for the BUCK, which is also conducive to the selection of the BUCK.

[0003] The series voltage regulation principle adjusts the input voltage to the required output voltage through a power transistor. The excess energy in the middle is converted into heat and dissipated. The large input-output voltage difference means high loss and heat generation, which requires a larger heat dissipation volume and better heat dissipation conditions, resulting in series voltage regulation not being suitable for a wide range of inputs.

[0004] Different battery systems, such as 48V and 80V voltage ranges, can use the same parameters for BUCK, which is also beneficial for procurement and production. Currently, auxiliary power supplies tend to be unified and compatible with the entire low-voltage battery system. In this way, how series voltage regulation copes with a wide input range becomes a challenge.

[0005] Therefore, it is an urgent problem to provide a wide range series voltage regulator circuit design method to improve wide range input compatibility and enable the series voltage regulator to automatically adjust the output. Summary of the invention

[0006] In response to the above-mentioned technical problems, the present invention provides a wide-range series voltage regulator circuit design method, which can automatically adjust the output according to the input voltage to meet the requirements of the subsequent BUCK input, while ensuring that the power crystal loss is within its tolerance range.

[0007] The present invention provides a method for designing a wide range series voltage stabilization circuit, the method comprising the following steps: A voltage judgment unit is provided for comparing the input voltage with a preset threshold value; A voltage stabilizing unit is provided to output two different voltage levels according to the comparison result of the voltage judging unit. When the input voltage is greater than a preset threshold, the voltage stabilizing unit outputs a high voltage level, and when the input voltage is less than the preset threshold, the voltage stabilizing unit outputs a low voltage level.

[0008] Specifically, the voltage judgment unit includes: a first voltage regulator tube and a third transistor; The cathode of the first voltage regulator is connected to the circuit input terminal, and the anode is connected to the base of the third transistor, and the stable voltage of the first voltage regulator is a preset threshold value; The collector of the third transistor is connected to the circuit input terminal, and the emitter is grounded.

[0009] Specifically, the anode of the first voltage regulator tube is connected to the base of the third transistor via the third current limiting circuit, and the collector of the third transistor is connected to the circuit input terminal via the second current limiting circuit.

[0010] Specifically, the voltage stabilizing unit includes: a first transistor, a second transistor, a second voltage stabilizing tube and a third voltage stabilizing tube; The first transistor is connected between the circuit input terminal and the circuit output terminal via its collector and emitter; The anode of the second voltage regulator tube is connected in series with the cathode of the third voltage regulator tube, the cathode of the second voltage regulator tube is connected to the base of the first transistor, and the anode of the third voltage regulator tube is grounded; The collector of the second transistor is connected between the second voltage regulator tube and the third voltage regulator tube, the base of the second transistor is connected to the collector of the third transistor, and the emitter of the second transistor is grounded.

[0011] Specifically, the collector of the first transistor is connected to the circuit input terminal, and the emitter is connected to the circuit output terminal.

[0012] Specifically, the base of the first transistor and the cathode of the second voltage-stabilizing tube are connected to the circuit input terminal via the first current limiting circuit.

[0013] Specifically, the current limiting circuit includes a resistor, and the current limiting circuit is a first current limiting circuit, a second current limiting circuit, or a third current limiting circuit.

[0014] Specifically, the transistor is an NPN transistor, and the transistor is a first transistor, a second transistor, or a third transistor.

[0015] Specifically, the stable voltage set by the second voltage regulator is a low voltage level, and the stable voltage set by the third voltage regulator is a difference between a high voltage level and a low voltage level.

[0016] Specifically, the BUCK operating conditions are determined according to the load conditions, including input power P, maximum input voltage, and minimum input voltage; The high voltage level is set according to the maximum input voltage, and the low voltage level is set according to the minimum input voltage.

[0017] The present invention discloses a method for designing a wide range series voltage stabilization circuit, which has at least the following beneficial effects compared with the prior art: 1. It can adapt to a wide range of input voltage, improving the compatibility and reliability of the auxiliary power supply.

[0018] 2. Adjust the series voltage regulator output according to the input voltage, and set multi-point output according to the heat dissipation needs. In the entire wide range input system, the auxiliary power supply realizes the same design.

[0019] 3. Automatically adjust the output according to the input series voltage regulation to meet the input of the subsequent BUCK and ensure that the power crystal loss is within its tolerance range, thereby improving efficiency.

[0020] 4. Simplify power supply design, reduce costs and maintenance difficulties. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0022] Figure 1 A flow chart of a method for designing a wide range series voltage stabilizing circuit according to the present invention; Figure 2 It is a circuit diagram of the wide range series voltage stabilizing circuit of the present invention. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. Obviously, the specific embodiments described herein are only used to explain the present invention and are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention.

[0024] It should be noted that if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0025] Figure 1 FIG. 1 is a flow chart of an embodiment of a wide range series voltage stabilization circuit design method provided by the present invention, and the flow chart specifically includes the following steps: A voltage judgment unit is provided for comparing the input voltage with a preset threshold value; A voltage stabilizing unit is provided to output two different voltage levels according to the comparison result of the voltage judging unit. When the input voltage is greater than a preset threshold, the voltage stabilizing unit outputs a high voltage level, and when the input voltage is less than the preset threshold, the voltage stabilizing unit outputs a low voltage level.

[0026] The voltage stabilizing unit selectively outputs at least two different voltage levels VO-H and VO-L according to the comparison result of the voltage judging unit, wherein when the input voltage VIN is greater than a preset threshold value VIN-REF, the voltage stabilizing unit outputs a high voltage level VO-H, and when the input voltage VIN is less than the threshold value VIN-REF, the voltage stabilizing unit outputs a low voltage level VO-L.

[0027] Figure 2 A circuit diagram of a wide range series voltage stabilization circuit provided in an embodiment of the present application is shown, and the transistors in this embodiment are all NPN triodes.

[0028] Specifically, the voltage judgment unit includes: a first voltage regulator tube and a third transistor, the cathode of the first voltage regulator tube is connected to the circuit input end, the anode is connected to the base of the third transistor, and the stable voltage of the first voltage regulator tube is a preset threshold; the collector of the third transistor is connected to the circuit input end, and the emitter is grounded.

[0029] like Figure 2 As shown, the voltage judgment unit includes a first voltage regulator tube D1 and a third transistor Q3, the cathode of the first voltage regulator tube D1 is connected to the circuit input terminal, the anode is connected to the base of the third transistor Q3, the stable voltage of the first voltage regulator tube is a preset threshold value VIN-REF, the collector of the third transistor Q3 is connected to the circuit input terminal, and the emitter is grounded. Specifically, the anode of the first voltage regulator tube D1 is connected to the base of the third transistor Q3 via a resistor R3, and the collector of the third transistor is connected to the circuit input terminal via a resistor R2.

[0030] A Zener diode (also called a Zener diode) is a special type of diode that is designed to maintain a constant voltage at a specific voltage (called its reverse breakdown voltage) regardless of changes in the current passing through it.

[0031] The set reference voltage of the Zener diode is its reverse breakdown voltage, which is determined by its physical properties. In the circuit, when the input voltage is applied to the Zener diode, if the input voltage is lower than the reference voltage, the Zener diode will not conduct and maintain a high-impedance state; when the input voltage exceeds the reference voltage, the Zener diode conducts and enters a low-impedance state, and maintains a voltage value of the reference voltage across its two ends.

[0032] The reference voltage VD1 of the first voltage regulator D1 is used as a preset threshold VIN-REF for judging the input voltage VIN. When the input voltage VIN exceeds the threshold VIN-REF, the first voltage regulator D1 is turned on, current flows through the resistor R3, and the third transistor Q3 is turned on. When the input voltage VIN is less than the threshold VIN-REF, the first voltage regulator D1 is turned off, no current flows through the resistor R3, and the third transistor Q3 is turned off.

[0033] The voltage regulation value VD1 is a key parameter in the entire circuit design. It not only determines the working state of the circuit, but also directly affects the stability of the output voltage and the efficiency of the circuit. By setting the voltage regulation value VD1, a flexible response to the input voltage can be achieved, thereby maintaining a stable output voltage under different input voltage conditions.

[0034] Specifically, the voltage stabilizing unit includes: a first transistor, a second transistor, a second voltage-stabilizing tube and a third voltage-stabilizing tube. The first transistor is connected between a circuit input end and a circuit output end via its collector and emitter; the anode of the second voltage-stabilizing tube is connected in series with the cathode of the third voltage-stabilizing tube, the cathode of the second voltage-stabilizing tube is connected to the base of the first transistor, and the anode of the third voltage-stabilizing tube is grounded; the collector of the second transistor is connected between the second voltage-stabilizing tube and the third voltage-stabilizing tube, the base of the second transistor is connected to the collector of the third transistor, and the emitter is grounded.

[0035] like Figure 2 As shown, the voltage stabilizing unit includes a first transistor Q1, a second transistor Q2, a second voltage stabilizing tube D2 and a third voltage stabilizing tube D3, the collector of the first transistor Q1 is connected to the circuit input end, the emitter is connected to the circuit output end, the anode of the second voltage stabilizing tube D2 is connected in series with the cathode of the third voltage stabilizing tube D3, the cathode of the second voltage stabilizing tube D2 is connected to the base of the first transistor Q1, the anode of the third voltage stabilizing tube D3 is grounded, and the collector of the second transistor Q2 is connected between the second voltage stabilizing tube D2 and the third voltage stabilizing tube D3, the base of the second transistor Q2 is connected to the collector of the third transistor Q3, and the emitter of the second transistor is grounded. Specifically, the base of the first transistor Q1 and the cathode of the second voltage stabilizing tube D2 are connected to the circuit input end via the resistor R1.

[0036] The second transistor Q2 is a key component between the voltage judgment unit and the voltage stabilizing unit. Its conduction state is affected by the output of the voltage judgment unit and directly affects the output voltage of the voltage stabilizing unit. It plays the role of a bridge in the circuit, connecting the voltage judgment unit and the voltage stabilizing unit, and adjusting the output voltage according to the comparison result between the input voltage and the threshold.

[0037] The conduction state of the second transistor Q2 is controlled by the third transistor Q3. When the third transistor Q3 is turned on, the collector of the third transistor Q3 is connected to the base of the second transistor Q2, pulling down the base of the second transistor Q2, causing the second transistor Q2 to be turned off. The base voltage of the first transistor Q1 is the sum of the regulated voltage values ​​of the second voltage regulator tube D2 and the third voltage regulator tube D3. The output of the first transistor Q1 adopts an emitter follower, that is, the voltage level VO-H of the series regulated output VD2+VD3; when the third transistor Q3 is turned off, current flows through the base of the second transistor Q2, the second transistor Q2 is turned on, the collector of the second transistor Q2 is connected to the cathode of the third voltage regulator tube D3, the third voltage regulator tube D3 is bypassed, and the base voltage of the first transistor Q1 is the regulated voltage value of the second transistor D2, that is, the voltage level VO-L of the series regulated output VD2.

[0038] The voltage judgment unit controls the conduction state of the third transistor Q3 and the second transistor Q2 by detecting the comparison result of the input voltage VIN and the preset threshold VIN-REF, thereby affecting the working mode of the subsequent circuit. The voltage stabilizing unit adjusts the output voltage level according to the comparison result of the voltage judgment unit to achieve stable output of a wide range of input voltages.

[0039] In the series voltage regulator circuit, the voltage regulator and the power transistor Q1 are connected in series, which means that the current flows directly into the power transistor Q1 after passing through the voltage regulator, and then reaches the load. The voltage regulator provides a reference voltage, and the power transistor Q1 adjusts the voltage of its emitter according to this reference voltage and the required output voltage to achieve the voltage regulation function. Specifically, the base voltage of the power transistor Q1 is determined by the voltage regulation value of the voltage regulators D2 and D3, and the emitter of the power transistor Q1 provides a stable output voltage. This design allows the circuit to maintain a stable output voltage by adjusting the conduction degree of the power transistor Q1 under different input voltage conditions.

[0040] Specifically, the stable voltage set by the second voltage regulator is a low voltage level, and the stable voltage set by the third voltage regulator is a difference between a high voltage level and a low voltage level.

[0041] Specifically, the BUCK working conditions are determined according to the load conditions, including input power P, maximum input voltage and minimum input voltage; a high voltage level is set according to the maximum input voltage, and a low voltage level is set according to the minimum input voltage.

[0042] According to the load conditions, first determine the BUCK working conditions: input power P, maximum input VIN-MAX and minimum output VIN-MIN, where the maximum input VIN-MAX and the minimum output VIN-MIN are the output voltage range of the series voltage regulator. Set the input judgment threshold VIN-REF. When VIN>VIN-REF, the series voltage regulator outputs VO-H, and the transistor loss is (VIN-VO-H)*P / VO-H; when VIN<VIN-REF, the series voltage regulator outputs VO-L, and the transistor loss is (VIN-VO-L)*P / VO-L. Select the appropriate output voltage based on the loss to ensure that the transistor loss is within its tolerance range.

[0043] Preferably, multiple input judgment thresholds can be set as required to achieve a series voltage stabilization multi-level output.

[0044] It should be understood that, although each step in the flow chart of each embodiment of the present invention is shown in sequence according to the indication of the arrow, these steps are not necessarily performed in sequence according to the order indicated by the arrow. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be performed in other orders. Moreover, at least a portion of the steps in each embodiment may include a plurality of sub-steps or a plurality of stages, and these sub-steps or stages are not necessarily performed at the same time, but can be performed at different times, and the execution order of these sub-steps or stages is not necessarily performed in sequence, but can be performed in turn or alternately with at least a portion of other steps or sub-steps or stages of other steps.

[0045] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the above-mentioned program can be stored in a non-volatile computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application may include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0046] The above embodiments only express the preferred implementation mode of the present invention, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A method for designing a wide range series voltage stabilization circuit, characterized in that: The steps include: A voltage judgment unit is provided for comparing the input voltage with a preset threshold value; A voltage stabilizing unit is provided, which is used to output two different voltage levels according to the comparison result of the voltage judgment unit. When the input voltage is greater than the preset threshold, the voltage stabilizing unit outputs a high voltage level, and when the input voltage is less than the preset threshold, the voltage stabilizing unit outputs a low voltage level.

2. The method according to claim 1, characterized in that The voltage judgment unit includes: a first voltage regulator tube and a third transistor; The cathode of the first voltage regulator is connected to the circuit input terminal, and the anode is connected to the base of the third transistor, and the stable voltage of the first voltage regulator is the preset threshold value; The collector of the third transistor is connected to the circuit input terminal, and the emitter is grounded.

3. The method according to claim 2, characterized in that The anode of the first voltage regulator tube is connected to the base of the third transistor via a third current limiting circuit, and the collector of the third transistor is connected to the circuit input end via a second current limiting circuit.

4. The method according to claim 2, characterized in that: The voltage stabilizing unit comprises: a first transistor, a second transistor, a second voltage stabilizing tube and a third voltage stabilizing tube; The first transistor is connected between the circuit input terminal and the circuit output terminal via its collector and emitter; The anode of the second voltage regulator tube is connected in series with the cathode of the third voltage regulator tube, the cathode of the second voltage regulator tube is connected to the base of the first transistor, and the anode of the third voltage regulator tube is grounded; The collector of the second transistor is connected between the second voltage regulator tube and the third voltage regulator tube, the base is connected to the collector of the third transistor, and the emitter is grounded.

5. The method according to claim 4, characterized in that The collector of the first transistor is connected to the circuit input terminal, and the emitter is connected to the circuit output terminal.

6. The method according to claim 5, characterized in that The base of the first transistor and the cathode of the second voltage-stabilizing tube are connected to the circuit input terminal via a first current limiting circuit.

7. The method according to claim 3 or 6, characterized in that: The current limiting circuit includes a resistor, and the current limiting circuit includes the first current limiting circuit, the second current limiting circuit, or the third current limiting circuit.

8. The method according to claim 2 or 4, characterized in that: The transistor is an NPN transistor, and the transistor includes the first transistor, the second transistor, or the third transistor.

9. The method according to claim 4, characterized in that The stable voltage set by the second voltage regulator is the low voltage level, and the stable voltage set by the third voltage regulator is the difference between the high voltage level and the low voltage level.

10. The method according to claim 1, characterized in that Determine the BUCK operating conditions according to the load conditions, including input power P, maximum input voltage and minimum input voltage; The high voltage level is set according to the maximum input voltage, and the low voltage level is set according to the minimum input voltage.

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