Low-power-consumption direct-current step-down circuit
By designing a low-power DC step-down circuit that utilizes depletion N-channel field effect transistors and voltage-regulating diodes, the problems of large size, high cost and high energy consumption in the step-down mode of low-power circuits in the prior art are solved, and the balance of efficient step-down and low power consumption is achieved.
Patent Information
- Application Number
- CN202411768802.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-04
- Publication Date
- 2025-03-14
AI Technical Summary
In existing low-power small signal circuits, the commonly used LDO or switching power supply step-down method has problems such as large size, high cost and low power utilization rate in low-power usage scenarios, resulting in high energy consumption.
A low-power DC step-down circuit is designed, and the gate of the depletion N-channel field effect tube and the voltage stabilization diode is used as the core, and the gate of the depletion N-channel field effect tube is connected to the positive electrode of the voltage stabilization diode, and the source is connected to the positive electrode of the voltage stabilization diode through the first resistor, so as to keep the voltage of the output terminal consistent during the rising stage of the input power supply, and maintain the target voltage after exceeding a certain value, so that the overall power consumption is low.
It realizes efficient step-down in low-power scenarios, low overall power consumption, high power utilization, wide application range and flexible configuration, and has self-protection, micro-ampere level of quiescent current, reduced conversion loss and improved conversion efficiency.
Smart Images
Figure CN119628411A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a step-down circuit, in particular to a low-power DC step-down circuit. Background Art
[0002] Currently, 3-24V DC power supplies are often used in low-power small signal circuits. The usual design is to step down the high input power supply through an LDO chip or a switching power supply chip before use.
[0003] Although this LDO or switching power supply step-down method has a large output power, it is large in size and high in cost. In addition, when used in low-power usage scenarios, the power utilization rate is not high, resulting in high energy consumption. Summary of the invention
[0004] The purpose of the present invention is to provide a low-power DC step-down circuit, with a depletion-type N-channel field effect transistor and a Zener diode as the core, connecting the gate of the depletion-type N-channel field effect transistor to the positive electrode of the Zener diode, and connecting the source of the depletion-type N-channel field effect transistor to the positive electrode of the Zener diode through a first resistor, so that when the input power is in the rising stage, the voltage of the output terminal is consistent with the actual voltage of the input power supply, and the voltage of the output terminal is maintained at the target voltage after exceeding a certain value, and the entire circuit has low power consumption.
[0005] The purpose of the present invention can be achieved by the following technical solutions:
[0006] A low-power DC step-down circuit comprises a depletion-type N-channel field effect transistor, a voltage-stabilizing diode, a first resistor, a second resistor and an output terminal, wherein the drain of the depletion-type N-channel field effect transistor is connected to an input power supply, the gate is connected to the first end of the second resistor, the source is connected to the first end of the first resistor, the positive electrode of the voltage-stabilizing diode is respectively connected to the second end of the second resistor and the second end of the first resistor, the negative electrode is grounded, and the first end of the first resistor is also connected to the output terminal.
[0007] The circuit further comprises a filter capacitor, one end of which is connected to the output terminal, and the other end of which is connected to the cathode of the voltage-stabilizing diode.
[0008] The capacitance of the filter capacitor is 1 microfarad.
[0009] The voltage stabilization value of the voltage stabilizing diode is:
[0010] U Z =VOUT*+V GS
[0011] Among them: U Z is the voltage regulation value of the Zener diode, VOUT* is the target output voltage, VGS It is the turn-off voltage of the depletion-type N-channel field effect transistor.
[0012] The depletion-type N-channel field effect transistor has a turn-off voltage V GS is -1V.
[0013] The circuit further comprises a fuse group, and the fuse group is arranged between the source of the depletion type N-channel field effect transistor and the first resistor.
[0014] The fuse group includes a temperature fuse and a current limiting fuse.
[0015] The first resistor and the second resistor are both fixed value resistors.
[0016] The resistance of the first resistor is more than 10 times the resistance of the second resistor.
[0017] The resistance value of the first resistor is 15 times the resistance value of the second resistor.
[0018] Compared with the prior art, the present invention has the following beneficial effects:
[0019] 1. With a depletion-type N-channel field effect transistor and a Zener diode as the core, the gate of the depletion-type N-channel field effect transistor is connected to the anode of the Zener diode, and the source of the depletion-type N-channel field effect transistor is connected to the anode of the Zener diode through a first resistor, so that when the input power is in the rising stage, the voltage of the output terminal is consistent with the actual voltage of the input power supply, and the voltage of the output terminal is maintained at the target voltage after exceeding a certain value, and the whole circuit has low power consumption.
[0020] 2. Filter capacitors can maintain the stability of power output.
[0021] 3. The voltage stabilization value of the voltage stabilizing diode can be configured to achieve outputs of different voltage levels, which has a wide range of applications and flexible configuration.
[0022] 4. Stable and reliable, with self-protection function.
[0023] 5. Selecting a larger resistor for the first resistor than the second resistor can make the static current of the circuit reach the microampere level, effectively reducing the conversion loss of the circuit and improving the conversion efficiency of the power supply. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 It is a structural schematic diagram of the present invention;
[0025] Among them: V1, depletion type N-channel field effect transistor, R1, first resistor, R2, second resistor, D1, voltage regulator diode, C1, filter capacitor, VOUT, output terminal, F1, fuse group, VIN, input power supply. DETAILED DESCRIPTION
[0026] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.
[0027] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.
[0028] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "proximal", "distal", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance. Physical quantities in formulas, if not separately marked, should be understood as basic quantities of the base units of the International System of Units, or derived quantities derived from the basic quantities through mathematical operations such as multiplication, division, differentiation or integration.
[0029] In addition, the terms "horizontal", "vertical", "overhanging" and the like do not mean that the components are required to be absolutely horizontal or overhanging, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.
[0030] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0031] In conjunction with the accompanying drawings, some embodiments of the present invention are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments may be combined with each other.
[0032] A low power DC step-down circuit, such as Figure 1As shown, it includes a depletion-type N-channel field effect transistor V1, a voltage-stabilizing diode D1, a first resistor R1, a second resistor R2 and an output terminal VOUT, wherein the drain of the depletion-type N-channel field effect transistor V1 is connected to the input power supply VIN, the gate is connected to the first end of the second resistor R2, the source is connected to the first end of the first resistor R1, the anode of the voltage-stabilizing diode D1 is respectively connected to the second end of the second resistor R2 and the second end of the first resistor R1, the cathode is grounded, and the first end of the first resistor R1 is also connected to the output terminal VOUT.
[0033] With a depletion-type N-channel field effect transistor V1 and a Zener diode D1 as the core, the gate of the depletion-type N-channel field effect transistor V1 is connected to the anode of the Zener diode D1, and the source of the depletion-type N-channel field effect transistor V1 is connected to the anode of the Zener diode D1 through a first resistor R1, so that when the input power supply VIN is in the rising stage, the voltage of the output terminal VOUT can be consistent with the actual voltage of the input power supply VIN, and the voltage of the output terminal VOUT is maintained at the target voltage after exceeding a certain value, and the entire circuit has low power consumption.
[0034] In most embodiments, the circuit also includes a filter capacitor C1, one end of the filter capacitor C1 is connected to the output terminal VOUT, and the other end is connected to the cathode of the voltage-stabilizing diode D1. The filter capacitor C1 can maintain the stability of the power supply output. In this embodiment, the capacitance of the filter capacitor C1 is 1 microfarad.
[0035] In addition, in this application, the voltage stabilization value of the voltage stabilizing diode D1 is:
[0036] U Z =VOUT*+V GS
[0037] Among them: U Z is the voltage regulation value of the Zener diode D1, VOUT* is the target output voltage, V GS It is the turn-off voltage of the depletion type N-channel field effect transistor V1.
[0038] Therefore, the voltage stabilization value of the voltage stabilizing diode D1 can be configured to achieve outputs of different voltage levels, which has a wide range of applications and flexible configuration.
[0039] In particular, in this embodiment, the turn-off voltage V GS If the drain-source saturation voltage VDS is as high as 800V, the drain-source saturation current is 100mA, and the on-resistance is less than 50Ω.
[0040] In addition, in some embodiments, the circuit further includes a fuse group F1, which is arranged between the source of the depletion-type N-channel field effect transistor V1 and the first resistor R1. In this embodiment, the fuse group F1 includes a temperature fuse and a current-limiting fuse. The positive temperature thermistor fuse is selected according to the actual needs, and the model of the corresponding parameters is selected to meet the requirements that the resistance value increases rapidly when the temperature is greater than the specified value, and the current exceeds the limit and the fuse is blown.
[0041] The first resistor R1 and the second resistor R2 are both fixed resistors, and the resistance of the first resistor R1 is more than 10 times the resistance of the second resistor R2. The first resistor R1 is selected to be larger than the second resistor R2, so that the static current of the circuit can reach the microampere level, effectively reducing the conversion loss of the circuit and improving the conversion efficiency of the power supply. In this embodiment, the resistance of the first resistor R1 is 15 times the resistance of the second resistor R2. Specifically, the first resistor R1 is selected to be a 15kΩ resistor, and the second resistor R2 is selected to be a 1kΩ resistor.
[0042] Here’s how this application works:
[0043] Assuming that a 12V power supply voltage needs to be output, the voltage regulator diode D1 selects the SODZ11A-SH voltage regulator tube, and the stable voltage Uz of the voltage regulator tube is 11V. Therefore, when the input power supply VIN slowly rises from 0V, below 11V, the gate voltage of the depletion type N-channel field effect transistor V1 is equal to the source voltage, so the drain to source of the depletion type N-channel field effect transistor V1 is always kept in the on state, and the voltage at VM is the value of the actual input power supply VIN, and the output terminal VOUT is also the voltage value of the actual input power supply VIN.
[0044] When the input power supply VIN rises to 11V or above, due to the turn-off voltage V of the depletion-type N-channel field effect transistor V1, GS The voltage is about -1V, so when the input power VIN is between 11V and 12V, the drain to source of the depletion-type N-channel field effect transistor V1 remains on. When the input power VIN rises to 12V or above, VM is still 11V, but the output terminal VOUT has become 12V. At this time, V GSWhen the voltage is greater than or equal to -1V, the drain and source of the depletion-type N-channel field effect transistor V1 stop conducting. At this time, the voltage value of the output terminal VOUT cannot continue to increase and remains at 12V. At this time, due to the shutdown of the depletion-type N-channel field effect transistor V1 and the power consumption of the load circuit, the voltage of the output terminal VOUT will drop. When it drops to a voltage equal to 11V of VM, the drain to source of the depletion-type N-channel field effect transistor V1 opens again. In this way, a stable 12V power supply voltage output is formed through the repeated conduction of the depletion-type N-channel field effect transistor V1 and the charging and discharging of the filter capacitor C1. The fuse group F1 plays a role in over-temperature protection and current limiting protection of the circuit. The first resistor R1 and the second resistor R2 play a role in current limiting to ensure that the current flowing through the voltage-stabilizing diode D1 is not too large.
Claims
1. A low power consumption DC step-down circuit, characterized in that: It includes a depletion-type N-channel field effect transistor, a voltage-stabilizing diode, a first resistor, a second resistor and an output terminal, wherein the drain of the depletion-type N-channel field effect transistor is connected to an input power supply, the gate is connected to a first end of the second resistor, the source is connected to a first end of the first resistor, the positive electrode of the voltage-stabilizing diode is respectively connected to the second end of the second resistor and the second end of the first resistor, the negative electrode is grounded, and the first end of the first resistor is also connected to the output terminal.
2. A low power consumption DC step-down circuit according to claim 1, characterized in that: The circuit further comprises a filter capacitor, one end of which is connected to the output terminal, and the other end of which is connected to the cathode of the voltage-stabilizing diode.
3. A low power consumption DC step-down circuit according to claim 1, characterized in that: The capacitance of the filter capacitor is 1 microfarad.
4. A low power consumption DC step-down circuit according to claim 1, characterized in that: The voltage stabilization value of the voltage stabilizing diode is: U Z =VOUT*+V GS Among them: U Z is the voltage regulation value of the Zener diode, VOUT* is the target output voltage, V GS It is the turn-off voltage of the depletion-type N-channel field effect transistor.
5. A low power consumption DC step-down circuit according to claim 4, characterized in that: The depletion-type N-channel field effect transistor has a turn-off voltage V GS is -1V.
6. A low power consumption DC step-down circuit according to claim 1, characterized in that: The circuit further comprises a fuse group, and the fuse group is arranged between the source of the depletion type N-channel field effect transistor and the first resistor.
7. A low power consumption DC step-down circuit according to claim 6, characterized in that: The fuse group includes a temperature fuse and a current limiting fuse.
8. The low power consumption DC step-down circuit according to claim 1, characterized in that: The first resistor and the second resistor are both fixed value resistors.
9. A low power consumption DC step-down circuit according to claim 8, characterized in that: The resistance of the first resistor is more than 10 times the resistance of the second resistor.
10. A low power consumption DC step-down circuit according to claim 9, characterized in that: The resistance value of the first resistor is 15 times the resistance value of the second resistor.