Pulse width modulation signal detection circuit, electronic equipment and lithium ion battery pack
By designing a circuit structure with zero-crossing detection, RC integration, and filtering, the accuracy problem of PWM signal detection was solved, enabling the rapid conversion of signals into digital or analog quantities and reducing costs.
Patent Information
- Application Number
- CN202511779505.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-28
- Publication Date
- 2026-02-27
AI Technical Summary
In existing technologies, it is difficult to achieve fast and accurate detection of PWM signals, resulting in insufficient accuracy in converting signals into digital or analog quantities.
The amplitude of the PWM signal is corrected by a zero-crossing detection unit, the integral correction is performed by an RC integrator unit, and the ripple is eliminated by a filter unit. The design includes a combination circuit of voltage comparator and capacitor-resistor network.
It enables fast and accurate detection of PWM signals, improves the accuracy of signal conversion to digital or analog quantities, and reduces production and maintenance costs.
Smart Images
Figure CN121585145A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of PWM signal modulation, and particularly relates to a pulse width modulation signal detection circuit, an electronic device and a lithium ion battery pack. BACKGROUND
[0002] PWM pulse width modulation, also known as pulse duration modulation (PDM) or pulse length modulation (PLM), is any method of representing a signal as a square wave with different duty cycles (and different periods for some methods). PWM signal modulation is to change the duty cycle of a square wave signal while keeping the frequency unchanged, thereby transmitting information. PWM signals are widely used in the industrial field, such as fan speed signals, display screen dimming signals and the like. How to quickly and accurately detect PWM signals and convert them into digital or analog signals for easy detection is very important. SUMMARY
[0003] To solve the problems in the prior art, the application provides a pulse width modulation signal detection circuit, an electronic device and a lithium ion battery pack, which can quickly and accurately detect PWM signals and improve the accuracy of conversion of PWM signals into digital or analog signals.
[0004] To achieve the above object, the application adopts the following technical scheme: In a first aspect, a pulse width modulation signal detection circuit is provided, comprising: a zero-crossing detection unit for amplitude correction of a PWM signal; an RC integration unit for integral correction of the PWM signal after amplitude correction; and a filter unit for ripple elimination processing of the PWM signal after integral correction.
[0005] The above technical scheme corrects the amplitude of the input PWM signal through the zero-crossing detection unit, performs integral correction through the RC integration unit, and performs ripple elimination processing through the filter unit, thereby quickly and accurately detecting the PWM signal and improving the accuracy of conversion of the PWM signal into a digital or analog signal.
[0006] Further, the zero-crossing detection unit comprises a voltage comparator U1A, one end of a resistor R2 and one end of a resistor R3 are connected to the inverting input terminal of the voltage comparator U1A; one end of a resistor R4, one end of a resistor R6 and one end of a resistor R7 are connected to the non-inverting input terminal of the voltage comparator U1A; one end of a resistor R5, the other end of the resistor R6 and the input terminal of an RC integration unit are connected to the output terminal of the voltage comparator U1A; the other end of the resistor R2 is connected to the input PWM signal through a resistor R1, the common terminal of the resistor R2 and the resistor R1 is connected to the negative electrode of a diode D1, and the positive electrode of the diode D1 is grounded; the other end of the resistor R3, the other end of the resistor R4 and the other end of the resistor R5 are respectively connected to a 5V power supply; and the other end of the resistor R7 is grounded.
[0007] The above technical solution simplifies the circuit structure and reduces the production cost by specifically designing the circuit structure of the zero-crossing detection unit to realize the amplitude correction of the input PWM signal.
[0008] Further, the model of the voltage comparator U1A comprises LM193D.
[0009] The above technical solution reduces the energy consumption and improves the economy of the circuit by giving a specific model of the voltage comparator U1A, while ensuring the normal use of the function.
[0010] Further, the working voltage of the voltage comparator U1A is 5V.
[0011] The above technical solution improves the selection range of the voltage comparator U1A and the replaceability of the device while ensuring the normal use of the function by specifically limiting the working voltage of the voltage comparator U1A, thereby further reducing the maintenance cost.
[0012] Further, the RC integration unit comprises a resistor R8, one end of the resistor R8 is connected to the output terminal of the zero-crossing detection unit, and the other end of the resistor R8 is connected to one end of a capacitor C1 and the input terminal of a filter unit; the other end of the capacitor C1 is grounded.
[0013] The above technical solution simplifies the circuit structure and reduces the production cost by specifically designing the circuit structure of the RC integration unit to realize the integral correction of the input signal.
[0014] Further, the filter unit comprises a voltage comparator U1C, one end of the non-inverting input terminal of the voltage comparator U1C is connected to one end of the resistor R11, one end of the capacitor C2 and one end of the resistor R10, the output terminal of the voltage comparator U1C is connected to one end of the capacitor C3, one end of the resistor R12 and the inverting input terminal of the voltage comparator U1C; the other end of the resistor R10 is connected to one end of the resistor R9 and the other end of the capacitor C3, the other end of the resistor R9 is connected to the output terminal of the RC integration unit; the other end of the resistor R12 is connected to one end of the resistor R13 and one end of the capacitor C5; the other end of the resistor R13 is connected to one end of the capacitor C4 and the non-inverting input terminal of the voltage comparator U1B; the output terminal of the voltage comparator U1B is connected to the other end of the capacitor C5 and the inverting input terminal of the voltage comparator U1B; the other end of the capacitor C2, the other end of the resistor R11 and the other end of the capacitor C4 are grounded.
[0015] The technical scheme has the advantages that the circuit structure of the filter unit is designed, the function of eliminating the ripple of the input signal is realized, the circuit structure is simplified, and the production cost is reduced.
[0016] Further, the model of the voltage comparator U1C and the voltage comparator U1B comprises TL072ACD.
[0017] Further, the working voltage of the voltage comparator U1C and the voltage comparator U1B is 5V.
[0018] The technical scheme has the advantages that the working voltage of the voltage comparator U1C and the voltage comparator U1B is limited, the selection range of the voltage comparator U1C and the voltage comparator U1B is improved, the replaceability of the device is improved, and the maintenance cost is further reduced.
[0019] The technical scheme has the advantages that a specific model of the voltage comparator U1C and the voltage comparator U1B is given, the energy consumption is reduced, and the economy of the circuit is improved.
[0020] In the second aspect, an electronic device is provided, and the electronic device is configured with the pulse width modulation signal detection circuit in the first aspect.
[0021] The technical scheme has the advantages that the pulse width modulation signal detection circuit in the first aspect is configured in the electronic device, the PWM signal can be quickly and accurately detected, and the accuracy of converting the PWM signal into a digital signal or an analog signal is improved.
[0022] In the third aspect, a lithium ion battery pack is provided, and the lithium ion battery pack is configured with the pulse width modulation signal detection circuit in the first aspect.
[0023] The technical scheme has the beneficial effects that: the first aspect of the pulse width modulation signal detection circuit is configured in the lithium ion battery pack, so that the PWM signal can be quickly and accurately detected, the accuracy of converting the PWM signal into a digital signal or an analog signal is improved, the charging power is adjusted through the PWM signal, and the charging efficiency of the lithium ion battery pack is improved.
[0024] Compared with the prior art, the present application has the beneficial effects that: the zero-crossing detection unit for amplitude correction of the PWM signal, the RC integration unit for integral correction of the PWM signal after amplitude correction, and the filter unit for ripple elimination processing of the PWM signal after integral correction can quickly and accurately detect the PWM signal, and improve the accuracy of converting the PWM signal into a digital signal or an analog signal. BRIEF DESCRIPTION OF DRAWINGS
[0025] Figure 1 is a principle block diagram of a pulse width modulation signal detection circuit provided by an embodiment of the present application; Figure 2 is a signal processing flowchart of the pulse width modulation signal detection circuit in the embodiment of the present application; Figure 3 is Figure 1 a circuit principle schematic diagram of the zero-crossing detection unit in the embodiment; Figure 4 is a signal waveform diagram before and after processing by the zero-crossing detection unit; Figure 5 is Figure 1 a circuit principle schematic diagram of the RC integration unit in the embodiment; Figure 6 is a signal waveform diagram before and after processing by the RC integration unit; Figure 7 is Figure 1 a circuit principle schematic diagram of the filter unit in the embodiment; Figure 8 is a signal waveform diagram before and after processing by the filter unit. DETAILED DESCRIPTION
[0026] The present application will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical scheme of the present application, and cannot be used to limit the protection scope of the present application.
[0027] Embodiment one As shown in Figures 1-8 , a pulse width modulation signal detection circuit comprises: a zero-crossing detection unit for amplitude correction of a PWM signal; an RC integration unit for integral correction of the PWM signal after amplitude correction; and a filter unit for ripple elimination processing of the PWM signal after integral correction.
[0028] First is the zero-crossing detection unit, the actual PWM signal although the frequency is fixed, but due to the characteristics of the signal source itself, when changing the pulse width, the signal amplitude may change, that is, in the case of minimum duty cycle and maximum duty cycle, the output signal amplitude may change greatly relative to the 0 potential reference point.
[0029] Using the traditional integral means, the integral result will be abnormal due to the change of the signal relative to the 0 potential reference point. Therefore, it is necessary to first use the zero-crossing detection circuit to unify the amplitude of the signal and make the amplitude symbol consistent relative to the 0 potential reference point (that is, all positive signals or all negative signals, eliminating the positive and negative alternation of the PWM signal).
[0030] As shown in Figure 3 , the zero-crossing detection unit includes a voltage comparator U1A (model: LM193D), the inverting input terminal of the voltage comparator U1A is connected to one end of the resistor R2 (5.1kΩ) and one end of the resistor R3 (100kΩ); The non-inverting input terminal of the voltage comparator U1A is connected to one end of the resistor R4 (100kΩ), one end of the resistor R6 (20MΩ), and one end of the resistor R7 (10kΩ); The output terminal of the voltage comparator U1A is connected to one end of the resistor R5 (5.1kΩ), the other end of the resistor R6, and the input terminal of the RC integration unit; The other end of the resistor R2 is connected to the input PWM signal V1 (-0.8V~2.6V, 0.5ms~2ms) through the resistor R1 (5.1kΩ), and the common terminal of the resistor R2 and the resistor R1 is connected to the negative electrode of the diode D1 (model: 1N4148), and the positive electrode of the diode D1 is grounded; The other end of the resistor R3, the other end of the resistor R4, and the other end of the resistor R5 are respectively connected to the 5V power supply; The other end of the resistor R7 is grounded.
[0031] Figure 3 , V1 is the PWM signal source. U1A is a voltage comparator, and the working voltage of the voltage comparator U1A is 5V, for example, LM193D. The output terminal of the voltage comparator outputs the PWM signal after zero-crossing detection, and the actual effect is shown in Figure 4 . As can be seen, the original PWM signal in light blue (with positive and negative alternation) is unchanged in pulse width after zero-crossing detection, and the amplitude and signal positive and negative are unified, and the PWM signal after zero-crossing detection is all positive (as shown in Figure 4 in purple), and the amplitude is 5V.
[0032] The PWM signal after zero-crossing detection is input to the RC integration unit circuit, as shown in Figure 5As shown, the signal enters from the left and exits from the right. The RC integrator unit includes a resistor R8. One end of resistor R8 is connected to the output of the zero-crossing detection unit, and the other end of resistor R8 is connected to one end of capacitor C1 and the input of the filter unit; the other end of capacitor C1 is grounded. The resistance and capacitance values of resistor R8 (100kΩ) and capacitor C1 (1μF) need to be adjusted according to the characteristics of the PWM signal.
[0033] The PWM signal after passing through the RC integrator circuit will be integrated to a specific level. The PWM signal ( Figure 6 The larger the pulse width of the light blue pulse, the greater the signal after integration ( Figure 6 The higher the level (as indicated by the purple curve), the greater the signal level. The magnitude and frequency of the integrated signal ripple depend on the RC parameters of the integrating unit circuit and the frequency and amplitude of the PWM signal itself. The rise time of the integrated signal mainly depends on the time constant of the RC integrating unit circuit.
[0034] For the integrated signal, ripple needs to be eliminated. This can be achieved by setting up a filtering unit circuit and adding a multi-order low-pass filter, such as... Figure 7 The diagram shows a second-order active low-pass filter unit circuit. The filter unit includes a voltage comparator U1C (model: TL072ACD). The non-inverting input of voltage comparator U1C is connected to one end of resistor R11 (2.0MΩ), one end of capacitor C2 (1μF), and one end of resistor R10 (10kΩ). The output of voltage comparator U1C is connected to one end of capacitor C3 (1μF), one end of resistor R12 (10kΩ), and the inverting input of voltage comparator U1C. The other end of resistor R10 is connected to one end of resistor R9 (10kΩ) and the other end of capacitor C3. The other end of resistor R9 is connected to the output of the RC integrator; the other end of resistor R12 is connected to one end of resistor R13 (10kΩ) and one end of capacitor C5 (10μF); the other end of resistor R13 is connected to one end of capacitor C4 (1μF) and the non-inverting input of voltage comparator U1B (model: TL072ACD); the output of voltage comparator U1B is connected to the other end of capacitor C5 and the inverting input of voltage comparator U1B; the other ends of capacitor C2, resistor R11, and capacitor C4 are grounded. In this invention, the operating voltage of voltage comparators U1B and U1C is 5V.
[0035] By setting the cutoff frequency as low as possible and the signal attenuation outside the cutoff frequency as high as possible, a relatively stable DC level signal can be obtained. Figure 8As shown, the light blue signal is the high ripple integration result output by the RC integration unit circuit, and the purple signal is the available direct current signal through the multi-stage low-pass filter unit circuit. The voltage value of the direct current signal can directly correspond to the pulse width size of the initial PWM signal source, and the purpose of PWM signal detection is achieved. The PWM signal output by the filter unit is converted by a digital-to-analog converter and sent to a processor for processing and use.
[0036] The present application can quickly and accurately detect the PWM signal by using the zero-crossing detection unit for amplitude correction of the PWM signal, the RC integration unit for integration correction of the PWM signal after amplitude correction, and the filter unit for ripple elimination processing of the PWM signal after integration correction, thereby improving the accuracy of converting the PWM signal into a digital signal or an analog signal, reducing energy consumption, and improving the economy of the circuit.
[0037] Embodiment Two Based on the pulse width modulation signal detection circuit described in Embodiment One, the present embodiment provides an electronic device configured with the pulse width modulation signal detection circuit described in Embodiment One.
[0038] Embodiment Three Based on the pulse width modulation signal detection circuit described in Embodiment One, the present embodiment provides a lithium ion battery pack configured with the pulse width modulation signal detection circuit described in Embodiment One.
[0039] The above description is only the preferred embodiments of the present application, and it should be noted that for ordinary skilled in the art, without departing from the technical principles of the present application, a number of improvements and modifications can be made, and these improvements and modifications should be considered as the protection scope of the present application.
Claims
1. A pulse width modulation signal detection circuit, characterized in that, include: Zero-crossing detection unit used for amplitude correction of PWM signals; An RC integrator unit used for integrating and correcting amplitude-corrected PWM signals; A filter unit used for ripple elimination processing of integrally corrected PWM signals.
2. The pulse width modulation signal detection circuit according to claim 1, characterized in that, The zero-crossing detection unit includes a voltage comparator U1A. The inverting input of the voltage comparator U1A is connected to one end of resistor R2 and one end of resistor R3. The non-inverting input of the voltage comparator U1A is connected to one end of resistor R4, one end of resistor R6, and one end of resistor R7. The output of the voltage comparator U1A is connected to one end of resistor R5, the other end of resistor R6, and the input of the RC integration unit. The other end of resistor R2 is connected to the input PWM signal through resistor R1. The common terminal of resistors R2 and R1 is connected to the negative terminal of diode D1, and the positive terminal of diode D1 is grounded. The other ends of resistors R3, R4, and R5 are connected to a 5V power supply; the other end of resistor R7 is grounded.
3. The pulse width modulation signal detection circuit according to claim 2, characterized in that, The voltage comparator U1A includes the LM193D model.
4. The pulse width modulation signal detection circuit according to claim 2, characterized in that, The voltage comparator U1A operates at 5V.
5. The pulse width modulation signal detection circuit according to claim 1, characterized in that, The RC integration unit includes a resistor R8. One end of the resistor R8 is connected to the output terminal of the zero-crossing detection unit, and the other end of the resistor R8 is connected to one end of the capacitor C1 and the input terminal of the filter unit. The other end of the capacitor C1 is grounded.
6. The pulse width modulation signal detection circuit according to claim 1, characterized in that, The filtering unit includes a voltage comparator U1C. The non-inverting input terminal of the voltage comparator U1C is connected to one end of resistor R11, one end of capacitor C2, and one end of resistor R10. The output terminal of the voltage comparator U1C is connected to one end of capacitor C3, one end of resistor R12, and the inverting input terminal of the voltage comparator U1C. The other end of resistor R10 is connected to one end of resistor R9 and the other end of capacitor C3. The other end of resistor R9 is connected to the output of the RC integrator. The other end of resistor R12 is connected to one end of resistor R13 and one end of capacitor C5; the other end of resistor R13 is connected to one end of capacitor C4 and the non-inverting input of voltage comparator U1B; the output of voltage comparator U1B is connected to the other end of capacitor C5 and the inverting input of voltage comparator U1B. The other end of capacitor C2, the other end of resistor R11, and the other end of capacitor C4 are grounded.
7. The pulse width modulation signal detection circuit according to claim 6, characterized in that, The voltage comparators U1C and U1B include the model number TL072ACD.
8. The pulse width modulation signal detection circuit according to claim 6, characterized in that, The voltage comparators U1C and U1B operate at a voltage of 5V.
9. An electronic device, characterized in that, The electronic device is equipped with a pulse width modulation signal detection circuit as described in any one of claims 1 to 8.
10. A lithium-ion battery pack, characterized in that, The lithium-ion battery pack is equipped with a pulse width modulation signal detection circuit as described in any one of claims 1 to 8.