A hysteresis voltage detection circuit
By using voltage stabilization units, power switching circuits and voltage divider resistors in the circuit, combined with field effect transistors and adjustable voltage source, the voltage level drifting problem of the circuit when detecting the rotation point is solved, achieving low cost and low Voltage hysteresis control for power consumption.
Patent Information
- Application Number
- CN202010905664.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2020-09-01
- Publication Date
- 2024-12-10
- Estimated Expiration
- 2040-09-01
AI Technical Summary
When used for state-of-state detection, existing circuits are susceptible to process tolerances or changes in ambient temperature, resulting in severe voltage level drifting, resulting in low accuracy of voltage hysteresis operating points, high cost, large power consumption, and circuit. complex.
A hysteresis voltage detection circuit including a voltage stabilization unit, a first power switching circuit and a second power switching circuit is designed. A field effect transistor and an adjustable voltage source are used to control the voltage level through a voltage divider resistor to achieve hysteresis entry and Accurate control of the disengagement point avoids the use of comparator.
It realizes low cost, low power consumption and precise control of voltage hysteresis, reduces the impact of temperature changes on voltage, and avoids the high cost and complex circuit problems of traditional methods.
Smart Images
Figure CN112014624B_ABST
Abstract
Description
Technical Field
[0001] The present invention is a voltage detection circuit, and in particular relates to a hysteresis voltage detection circuit for detecting voltage changes to control voltage hysteresis. Background Art
[0002] In existing circuit implementations, the positive feedback function of the comparator is generally used to achieve the voltage hysteresis phenomenon. Furthermore, the traditional voltage hysteresis phenomenon can be adjusted by a power switch to adjust the reference voltage, and a comparator is used to produce a hysteresis voltage function. The bipolar junction transistor (BJT) used in conjunction with the comparator in the traditional method is easily affected by process tolerances or changes in ambient temperature and produces a serious voltage level drift phenomenon. When the circuit is used for transition point detection (such as temperature protection, avoiding noise interference / false operation, etc.), the corresponding operating point that produces voltage hysteresis is not accurate, resulting in the problem of being unable to accurately control the voltage hysteresis phenomenon. Furthermore, the comparator components used in the traditional method are more expensive, consume more power, and the corresponding circuit complexity is also higher.
[0003] Therefore, how to design a hysteresis voltage detection circuit, especially to solve the above-mentioned technical problems of the prior art, is an important topic studied by the inventor of this case. Summary of the invention
[0004] The purpose of the present invention is to provide a hysteresis voltage detection circuit to solve the technical problem that the circuit in the prior art is easily affected by process tolerance or changes in ambient temperature when used for transition point detection, resulting in serious voltage level drift, thereby achieving the purpose of low cost, low power consumption and precise control of voltage hysteresis.
[0005] In order to achieve the above-mentioned purpose, the hysteresis voltage detection circuit proposed by the present invention includes a voltage stabilizing unit, a first power switch circuit and a second power switch circuit. Among them, the voltage stabilizing unit includes an anode, a cathode and a reference end, the anode is grounded, and the cathode is coupled to an adjustable voltage source. The first power switch circuit includes a first power switch, and the first power switch is coupled to the cathode of the voltage stabilizing unit and the adjustable voltage source. The second power switch circuit includes a first voltage-dividing resistor, a second voltage-dividing resistor, a third voltage-dividing resistor and a second power switch, the second power switch is a field effect transistor, the reference end of the voltage stabilizing unit is coupled to the adjustable voltage source through the first voltage-dividing resistor, the second voltage-dividing resistor and the third voltage-dividing resistor are coupled to the second power switch, the second voltage-dividing resistor is grounded, the second power switch is coupled to the first power switch, and the second power switch is coupled to the first voltage-dividing resistor and the reference end of the voltage stabilizing unit through the second voltage-dividing resistor and the third voltage-dividing resistor. Among them, when the first power switch and the second power switch are both turned on, the first voltage-dividing resistor, the second voltage-dividing resistor and the third voltage-dividing resistor divide the adjustable voltage source, and generate a first voltage to the reference end of the voltage stabilizing unit, so that the voltage stabilizing unit is turned on. When the first power switch and the second power switch are both turned off, the first voltage-dividing resistor and the second voltage-dividing resistor divide the adjustable voltage source and generate a second voltage to the reference end of the voltage-stabilizing unit, so that the voltage-stabilizing unit is turned off.
[0006] Furthermore, in the hysteresis voltage detection circuit, the cathode of the voltage stabilizing unit is coupled to the adjustable voltage source via a first current limiting resistor.
[0007] Furthermore, in the hysteresis voltage detection circuit, the first power switch circuit further includes a diode and a second current limiting resistor, wherein the second current limiting resistor is coupled to the diode, and the first power switch is coupled to the first current limiting resistor and the voltage stabilizing unit through the second current limiting resistor and the diode.
[0008] Furthermore, in the hysteresis voltage detection circuit, the first power switch is grounded through the third current limiting resistor.
[0009] Furthermore, in the hysteresis voltage detection circuit, the third current limiting resistor is grounded through a Zener diode.
[0010] Furthermore, in the hysteresis voltage detection circuit, the first voltage is smaller than the second voltage.
[0011] Furthermore, in the hysteresis voltage detection circuit, the adjustable voltage source includes AC power or a sine wave generator.
[0012] Furthermore, in the hysteresis voltage detection circuit, the adjustable voltage source includes a thermistor.
[0013] Beneficial effects:
[0014] When using the hysteresis voltage detection circuit of the present invention, since the voltage level of the adjustable voltage source is variable, the hysteresis entry point and the hysteresis exit point where the hysteresis phenomenon occurs can be controlled according to the first voltage-dividing resistor, the second voltage-dividing resistor and the third voltage-dividing resistor with specific parameters. When the voltage level of the adjustable voltage source is adjusted to make the first power switch and the second power switch both turned on, the first voltage-dividing resistor, the second voltage-dividing resistor and the third voltage-dividing resistor divide the voltage of the adjustable voltage source and generate a first voltage to the reference end of the voltage stabilizing unit, so that the voltage stabilizing unit is turned on, and the hysteresis voltage detection circuit is at the hysteresis entry point. When the voltage level of the adjustable voltage source is adjusted to make the first power switch and the second power switch both turned off, the first voltage-dividing resistor and the second voltage-dividing resistor divide the voltage of the adjustable voltage source and generate a second voltage to the reference end of the voltage stabilizing unit, so that the voltage stabilizing unit is turned off, and the hysteresis voltage detection circuit is at the hysteresis exit point. Furthermore, since the second power switch of the voltage-dividing resistor (including the second voltage-dividing resistor and the third voltage-dividing resistor) below the hysteresis voltage detection circuit is a field effect transistor, the field effect transistor has better temperature stability than the bipolar junction transistor used in the conventional voltage hysteresis circuit, and the on-resistance of the field effect transistor is less susceptible to temperature changes and drift, and the influence of temperature on voltage can be reduced compared to the voltage-dividing resistor. Moreover, compared to the conventional method, the present invention also avoids the disadvantages of high cost, high power consumption and complex circuits caused by the use of comparators.
[0015] To this end, the hysteresis voltage detection circuit described in the present invention solves the technical problem that the circuit in the prior art is easily affected by process tolerance or changes in ambient temperature when used for transition point detection, resulting in serious voltage level drift, thereby achieving the purpose of low cost, low power consumption and precise control of voltage hysteresis. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] 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 some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.
[0017] Figure 1 It is a circuit structure diagram of the hysteresis voltage detection circuit of the present invention;
[0018] Figure 2 A waveform diagram showing the change of the hysteresis voltage measurement point Vo1 of the hysteresis voltage detection circuit of the present invention over time;
[0019] Figure 3This is a waveform diagram of the hysteresis phenomenon of the hysteresis voltage detection circuit of the present invention. When the voltage measured at the voltage measurement point Vin is V1, the first power switch Q1 is in the on state.
[0020] Among them, 10 is the first power switch circuit, 20 is the second power switch circuit, U1 is the voltage stabilizing unit, R11 is the first current limiting resistor, R12 is the second current limiting resistor, R13 is the third current limiting resistor, R1 is the first voltage dividing resistor, R2 is the second voltage dividing resistor, R3 is the third voltage dividing resistor, Q1 is the first power switch, Q2 is the second power switch, D1 is the diode, D3 is the Zener diode, Vin is the voltage measurement point, Vo1 is the voltage measurement point, Vref is the reference terminal, V is the adjustable voltage source, V1 is the voltage, V2 is the voltage, VD3 is the voltage, and T is the time axis. DETAILED DESCRIPTION
[0021] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention. Specific embodiment 1
[0023] The technical content and detailed description of the present invention are described as follows with reference to the accompanying drawings.
[0024] See also Figures 1 to 3 As shown, the hysteresis voltage detection circuit includes a voltage stabilizing unit U1, a first power switch circuit 10 and a second power switch circuit 20. The voltage stabilizing unit U1 includes an anode, a cathode and a reference terminal Vref, the anode of the voltage stabilizing unit U1 is grounded, and the cathode of the voltage stabilizing unit U1 is coupled to an adjustable voltage source V through a first current limiting resistor R11.
[0025] Furthermore, the voltage stabilizing unit U1 may be a TL431 adjustable shunt regulator from Texas Instruments (TI), but the present invention is not limited thereto, and a voltage measurement point Vin is provided between the first current limiting resistor R11 and the adjustable voltage source V.
[0026] Furthermore, the adjustable voltage source V may be a mains power source or a sine wave generator with a variable voltage level, or may be a detection circuit coupled to an electronic element with a negative temperature coefficient (NTC) such as a thermistor.
[0027] The first power switch circuit 10 includes a first power switch Q1, a diode D1, and a second current limiting resistor R12. In the embodiment of the present invention, two ends of the second current limiting resistor R12 are respectively coupled to the diode D1 and the first power switch Q1, and the diode D1 is coupled to the first current limiting resistor R11 and the voltage stabilizing unit U1. However, the present invention is not limited thereto. In other words, the diode D1 and the second current limiting resistor R12 can be coupled in series, that is, in different embodiments, two ends of the diode D1 are respectively coupled to the second current limiting resistor R12 and the first power switch Q1, and the second current limiting resistor R12 is coupled to the first current limiting resistor R11 and the voltage stabilizing unit U1. The first power switch Q1 can be an NPN type bipolar junction transistor (BJT), and the collector of the first power switch Q1 is coupled to the adjustable voltage source V and the first current limiting resistor R11. The base of the first power switch Q1 is sequentially coupled to the first current limiting resistor R11 and the voltage stabilizing unit U1 through the second current limiting resistor R12 and the diode D1. The emitter of the first power switch Q1 is coupled to the third current limiting resistor R13, and is grounded in sequence through the third current limiting resistor R13 and the Zener diode D3. A voltage measurement point Vo1 is provided between the third current limiting resistor R13 and the Zener diode D3. In another embodiment of the present invention not shown in the figure, the Zener diode D3 may not be required, that is, the emitter of the first power switch Q1 is only grounded through the third current limiting resistor R13. However, the present invention is not limited thereto.
[0028] The second power switch circuit 20 includes a first voltage-dividing resistor R1, a second voltage-dividing resistor R2, a third voltage-dividing resistor R3 and a second power switch Q2. The second power switch Q2 may be an N-type metal-oxide-semiconductor field effect transistor (MOSFET), but the present invention is not limited thereto. The reference terminal Vref of the voltage-stabilizing unit U1 is coupled to the adjustable voltage source V through the first voltage-dividing resistor R1. One end of the second voltage-dividing resistor R2 is coupled to the source of the second power switch Q2, and the other end is grounded. One end of the third voltage-dividing resistor R3 is coupled to the second voltage-dividing resistor R2, and the other end is coupled to the drain of the second power switch Q2. The gate of the second power switch Q2 is coupled to the emitter of the first power switch Q1, and the second power switch Q2 is coupled to the first voltage-dividing resistor R1 and the reference terminal Vref of the voltage-stabilizing unit U1 through the second voltage-dividing resistor R2 and the third voltage-dividing resistor R3.
[0029] When using the hysteresis voltage detection circuit of the present invention, since the voltage level of the adjustable voltage source V is variable (adjustable), the hysteresis entry point and hysteresis exit point where the hysteresis phenomenon occurs can be controlled according to the first voltage-dividing resistor R1, the second voltage-dividing resistor R2 and the third voltage-dividing resistor R3 with specific parameters. When the voltage level of the adjustable voltage source V is adjusted to make the first power switch Q1 and the second power switch Q2 both turned on (ON), the first voltage-dividing resistor R1, the second voltage-dividing resistor R2 and the third voltage-dividing resistor R3 divide the voltage of the adjustable voltage source V. At this time, the second voltage-dividing resistor R2 and the third voltage-dividing resistor R3 are connected in parallel, and then connected in series with the first voltage-dividing resistor R1, and a first voltage Vref-1 is generated to the reference terminal Vref of the voltage-stabilizing unit U1, so that the voltage-stabilizing unit U1 is turned on (assuming that the turn-on threshold voltage of TL431 is 2.5V). At this time, the hysteresis voltage detection circuit is at the hysteresis entry point.
[0030] Furthermore, when entering the hysteresis entry point, the voltage measured at the voltage measurement point Vin is V1 (in the embodiment of the present invention, the voltage V1 may be 14V), and the voltage waveform at the voltage measurement point Vo1 also changes accordingly with the time axis T (in milliseconds, μs), such as Figure 2 As shown. Since the voltage measured at the voltage measurement point Vin is V1, the first power switch Q1 is in the on state, so the voltage measured at the voltage measurement point Vo1 is the voltage VD3 of the Zener diode D3, as shown Figure 3 shown.
[0031] Furthermore, the value of the voltage V1 can be calculated by the following equation:
[0032]
[0033] And the value of the first voltage Vref-1 can be calculated by the following equation:
[0034]
[0035] When the voltage level of the adjustable voltage source V is adjusted to make the first power switch Q1 and the second power switch Q2 both turned off (OFF), the first voltage-dividing resistor R1 and the second voltage-dividing resistor R2 divide the adjustable voltage source V. At this time, the first voltage-dividing resistor R1 and the second voltage-dividing resistor R2 are connected in series, and generate a second voltage Vref-2 to the reference end Vref of the voltage-stabilizing unit U1, so that the voltage-stabilizing unit U1 is turned off (OFF). At this time, the hysteresis voltage detection circuit is at the hysteresis release point. In the embodiment of the present invention, the first voltage Vref-1 is less than the second voltage Vref-2. Further, when entering the hysteresis release point, the voltage measured at the voltage measurement point Vin is V2 (in the embodiment of the present invention, the voltage V2 can be 10V), and the voltage waveform of the voltage measurement point Vo1 also changes accordingly with the time axis T (in milliseconds, μs), such as Figure 2 As shown. Further, since the second power switch Q2 of the voltage-dividing resistor (including the second voltage-dividing resistor R2 and the third voltage-dividing resistor R3) below the hysteresis voltage detection circuit is a field effect transistor (FET), the field effect transistor has better temperature stability than the bipolar junction transistor (BJT) used in the traditional voltage hysteresis circuit, and the on-resistance of the field effect transistor is less susceptible to temperature changes and drift, the influence of temperature on voltage can be reduced compared to the first voltage-dividing resistor R1, the second voltage-dividing resistor R2 and the third voltage-dividing resistor R3. Moreover, compared with the traditional method, the present invention also avoids the disadvantages of high cost, high power consumption and complex circuits brought by the use of comparators.
[0036] Furthermore, the value of the voltage V2 can be calculated by the following equation:
[0037]
[0038] And the value of the second voltage Vref-2 can be calculated by the following equation:
[0039]
[0040] To this end, the hysteresis voltage detection circuit described in the present invention solves the technical problem that the circuit in the prior art is easily affected by process tolerance or changes in ambient temperature when used for transition point detection, resulting in serious voltage level drift, thereby achieving the purpose of low cost, low power consumption and precise control of voltage hysteresis.
[0041] The above description is only a detailed description and drawings of the preferred specific embodiments of the present invention, but the features of the present invention are not limited thereto, and are not intended to limit the present invention. The entire scope of the present invention shall be subject to the following patent application scope. All embodiments that conform to the spirit of the patent application scope of the present invention and similar variations thereof shall be included in the scope of the present invention. Any changes or modifications that can be easily thought of by anyone familiar with the art within the field of the present invention shall be covered by the following patent scope of this case.
Claims
1. A hysteresis voltage detection circuit, characterized in that: include: A voltage stabilizing unit, comprising an anode, a cathode and a reference terminal, wherein the anode is grounded and the cathode is coupled to an adjustable voltage source; A first power switch circuit includes a first power switch, wherein the first power switch is coupled to the cathode of the voltage stabilizing unit and the adjustable voltage source; as well as The second power switch circuit comprises a first voltage-dividing resistor, a second voltage-dividing resistor, a third voltage-dividing resistor and a second power switch; wherein the second power switch is a field-effect transistor, the reference end of the voltage-stabilizing unit is coupled to the adjustable voltage source through the first voltage-dividing resistor; the second voltage-dividing resistor and the third voltage-dividing resistor are coupled to the second power switch, the second voltage-dividing resistor is grounded, the second power switch is coupled to the first power switch, and the second power switch is coupled to the first voltage-dividing resistor and the reference end of the voltage-stabilizing unit through the second voltage-dividing resistor and the third voltage-dividing resistor; When the first power switch and the second power switch are both turned on, the first voltage-dividing resistor, the second voltage-dividing resistor and the third voltage-dividing resistor divide the voltage of the adjustable voltage source and generate a first voltage to the reference end of the voltage-stabilizing unit, so that the voltage-stabilizing unit is turned on; Wherein, when the first power switch and the second power switch are both turned off, the first voltage-dividing resistor and the second voltage-dividing resistor divide the adjustable voltage source and generate a second voltage to the reference end of the voltage-stabilizing unit, so that the voltage-stabilizing unit is turned off; Wherein, the first power switch is a bipolar junction transistor of NPN type, the collector of the first power switch is coupled to the adjustable voltage source and the first current limiting resistor, the base of the first power switch is coupled to the first current limiting resistor and the voltage stabilizing unit through the second current limiting resistor and the diode in sequence, the emitter of the first power switch is coupled to the third current limiting resistor, and is grounded through the third current limiting resistor and the Zener diode in sequence; The first power switch circuit also includes: a diode; and a second current limiting resistor coupled to the diode; Wherein, the first power switch is coupled to the first current limiting resistor and the voltage stabilizing unit through the second current limiting resistor and the diode; The first power switch is grounded through a third current limiting resistor; The third current limiting resistor is connected to ground via a Zener diode.
2. The hysteresis voltage detection circuit according to claim 1, characterized in that The cathode of the voltage stabilizing unit is coupled to the adjustable voltage source through a first current limiting resistor.
3. The hysteresis voltage detection circuit according to claim 1, characterized in that The first voltage is lower than the second voltage.
4. The hysteresis voltage detection circuit according to claim 1, characterized in that The adjustable voltage source includes mains power or a sine wave generator.
5. The hysteresis voltage detection circuit according to claim 1, characterized in that The adjustable voltage source includes a thermistor.