Transmitting end driving circuit

Abstract

The utility model relates to the field of driving circuits, in particular to a transmitting end driving circuit of a photoelectric proximity switch, which comprises a signal generating circuit, a low-pass filter circuit and a voltage follower circuit, the signal generating circuit is connected with the low-pass filter circuit, the low-pass filter circuit is connected with the voltage follower circuit, and the voltage follower circuit is connected with the signal generating circuit. The voltage following circuit forms an output end, and the effect consistency of photoelectric proximity switches in the same batch is improved on the premise that the photoelectric proximity switches are not changed by continuously adjusting the duty ratio of an input signal source in the signal generating circuit.

Description

Technical Field

[0001] The utility model relates to the field of driving circuits, in particular to a driving circuit for the transmitting end of an optoelectronic proximity switch. Background Art

[0002] In the switch interaction in today's society, the switch mode has gradually changed from the traditional mechanical switch to the physical change switch. Users can realize the on and off functions of the circuit through physical changes in the environment, such as changes in external parameters such as sound and brightness. Among them, the optoelectronic proximity switch is a common physical change switch, which uses the occlusion or reflection of the light beam by the detected object to connect the circuit through the synchronization circuit, so as to detect the presence or absence of the object.

[0003] In the prior art, the optoelectronic proximity switch is driven by connecting a DC power supply in series with a current-limiting resistor. The main factors affecting the output signal voltage range are the forward voltage drop VF of the light-emitting diode of the optoelectronic proximity switch and the current transfer ratio of the optoelectronic proximity switch. Among them, the structural assembly accuracy has a great influence on the current transfer ratio of the optoelectronic proximity switch, and the requirement for the structural assembly accuracy is very high. In the case of batch tooling, it is easy to cause inconsistent product effects. Summary of the Utility Model

[0004] Based on the above-mentioned disadvantages of the prior art, the utility model provides a driving circuit for the transmitting end and an optoelectronic proximity switch applying the same, which solves the problem of inconsistent effects between products in the case of batch tooling.

[0005] To achieve the above object, in the first aspect of the utility model, a driving circuit for the transmitting end is provided, which includes a signal generating circuit, a low-pass filtering circuit, and a voltage following circuit. The signal generating circuit is connected to the low-pass filtering circuit, the low-pass filtering circuit is connected to the voltage following circuit, and the voltage following circuit forms an output end.

[0006] Further, the signal generating circuit includes an input signal source and a first resistor. The input signal source is connected to the low-pass filtering circuit in one aspect and grounded through the first resistor in the other aspect.

[0007] Further, the input signal source is a PWM adjustment signal.

[0008] Further, the low-pass filter circuit includes a second resistor, a first capacitor, a third resistor, and a second capacitor. The input end of the second resistor is connected to the signal generation circuit. The output end of the second resistor is connected to the input end of the third resistor on one hand, and grounded through the first capacitor on the other hand. The output end of the third resistor is connected to the voltage follower circuit on one hand, and grounded through the second capacitor on the other hand. The third resistor and the second capacitor form a first-order low-pass filter circuit structure, and the second resistor, the first capacitor, the third resistor, and the second capacitor together constitute a second-order low-pass filter circuit structure.

[0009] Further, the voltage follower circuit includes a triode, a fourth resistor, and a third capacitor. The base of the triode forms the input end and is connected to the low-pass filter circuit. The collector of the triode is connected to the power supply. The emitter of the triode is connected to the input end of the fourth resistor. The output end of the fourth resistor is used as the output end of the emitter drive circuit on one hand, and grounded through the third capacitor on the other hand.

[0010] Optionally, the capacitance of the third capacitor is 10 nF.

[0011] In the second aspect of the present utility model, an optoelectronic proximity switch applying the emitter drive circuit is provided, which includes an optical emitter and an optical receiver. The optical emitter is a light-emitting diode. The input end of the optical emitter is connected to the output end of the emitter drive circuit, and the output end of the optical emitter is grounded. The optical receiver is a photosensitive triode. The input end of the optical receiver is connected to the power supply and the output signal source respectively. The power supply is connected to the optical receiver through a fifth resistor, and the output end of the receiver is grounded.

[0012] By the above method, by continuously adjusting the duty cycle of the input signal source in the signal generation circuit, the actual effect of the optoelectronic proximity switch is adjusted, and the effect consistency of the optoelectronic proximity switches in the same batch is improved without changing the optoelectronic proximity switch. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The drawings described herein are used to provide a further understanding of the present utility model and constitute a part of this application. The schematic embodiments of the present utility model and their descriptions are used to explain the present utility model and do not constitute an improper limitation to the present utility model. In the drawings:

[0014] Figure 1 It is a schematic circuit structure diagram of an optoelectronic proximity switch applying an emitter drive circuit. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0015] The following describes the implementation manners of the present utility model through specific examples. Those skilled in the art can easily understand other advantages and effects of the present utility model from the content disclosed in this specification. The present utility model can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present utility model.

[0016] It should be noted that the illustrations provided in this embodiment only schematically illustrate the basic concept of the present utility model. Therefore, only the components related to the present utility model are shown in the drawings, rather than being drawn according to the number, shape, and size of the components in actual implementation. The form, quantity, and ratio of each component in actual implementation can be arbitrarily changed, and the layout form of its components may also be more complex.

[0017] In the first aspect, referring to Figure 1 , an embodiment of the present utility model provides a transmitter drive circuit 10 for an optoelectronic proximity switch, including a signal generation circuit 11, a low-pass filter circuit 12, and a voltage follower circuit 13. The signal generation circuit 11 is connected to the low-pass filter circuit 12, the low-pass filter circuit 12 is connected to the voltage follower circuit 13, and the voltage follower circuit 13 forms an output terminal to form a forward current for the optoelectronic proximity switch.

[0018] The signal generation circuit 11 includes an input signal source and a first resistor R1. The input signal source is connected to the low-pass filter circuit 12 in the first aspect and grounded through the first resistor R1 in the second aspect.

[0019] As a preferred implementation manner, the input signal source is a PWM adjustment signal.

[0020] The low-pass filter circuit 12 includes a second resistor R2, a first capacitor C1, a third resistor R3, and a second capacitor C2. The input end of the second resistor R2 is connected to the signal generation circuit 11. As a preferred implementation manner, the second resistor R2 is connected to the input signal source. The output end of the second resistor R2 is connected to the input end of the third resistor R3 in the first aspect and grounded through the first capacitor C1 in the second aspect. The second resistor R2 and the first capacitor C1 form a first-order low-pass filter circuit structure. The output end of the third resistor R3 is connected to the voltage follower circuit 13 in the first aspect and grounded through the second capacitor C2 in the second aspect. The third resistor R3 and the second capacitor C2 form a first-order low-pass filter circuit structure. The second resistor R2, the first capacitor C1, the third resistor R3, and the second capacitor C2 together constitute a second-order low-pass filter circuit structure.

[0021] The voltage follower circuit 13 includes a triode Q1, a fourth resistor R4, and a third capacitor C3. The base of the triode Q1 forms an input terminal and is connected to the low-pass filter circuit 12. As a preferred embodiment, the base of the triode Q1 is connected to the third resistor R3. The collector of the triode Q1 is connected to the power supply, the emitter of the triode Q1 is connected to the input terminal of the fourth resistor R4, the output terminal of the fourth resistor R4 is, on the one hand, used as the output terminal of the emitter drive circuit 10, and on the other hand, is grounded through the third capacitor C3.

[0022] As a preferred embodiment, the capacitance of the third capacitor C3 is 10 nF.

[0023] Through the above embodiments, the signal generation circuit generates a regulation signal. The regulation signal forms a stable DC voltage through the low-pass filter circuit. The DC voltage is stepped down through the voltage follower circuit to form an output voltage, and the output voltage is output to the photoelectric proximity switch. Under the condition that the measured object contacts the photoelectric proximity switch, by continuously adjusting the duty cycle of the input signal source in the signal generation circuit, the actual effect of the photoelectric proximity switch is adjusted, and the effect consistency of the photoelectric proximity switches of the same batch is improved without changing the photoelectric proximity switch.

[0024] On the other hand, an embodiment of the present invention further provides a photoelectric proximity switch applying the emitter drive circuit 10, which includes a light emitter and a light receiver. The emitter drive circuit 10 is the emitter drive circuit 10 provided in the above embodiments. The light emitter is a light-emitting diode, the input terminal of the light emitter is connected to the output terminal of the emitter drive circuit 10, and the output terminal of the light emitter is grounded. The light receiver is a photosensitive triode, the input terminal of the light receiver is respectively connected to the power supply and the output signal source, the power supply is connected to the light receiver through a fifth resistor R5, and the output terminal of the receiver is grounded.

[0025] The above embodiments merely illustrate the principles and effects of the present invention, rather than limiting the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes completed by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A transmitting end driving circuit, characterized in that: It includes a signal generating circuit, a low-pass filtering circuit and a voltage following circuit. The signal generating circuit is connected to the low-pass filtering circuit, the low-pass filtering circuit is connected to the voltage following circuit, and the voltage following circuit forms an output end.

2. A transmitter driving circuit as claimed in claim 1, characterized in that: The signal generating circuit comprises an input signal source and a first resistor. The input signal source is connected to the low-pass filter circuit on a first aspect and is grounded through the first resistor on a second aspect.

3. A transmitter driving circuit as claimed in claim 2, characterized in that: The input signal source is a PWM regulation signal.

4. A transmitter driving circuit as claimed in claim 1, characterized in that: The low-pass filter circuit includes a second resistor, a first capacitor, a third resistor, and a second capacitor. The second resistor input end is connected to the signal generating circuit. The second resistor output end is first connected to the third resistor input end and second connected to ground via the first capacitor. The third resistor output end is first connected to a voltage follower circuit and second connected to ground via the second capacitor. The third resistor and the second capacitor form a first-order low-pass filter circuit structure. The second resistor, the first capacitor, the third resistor, and the second capacitor together constitute a second-order low-pass filter circuit structure.

5. A transmitter drive circuit as claimed in claim 1, characterized in that: The voltage follower circuit includes a transistor, a fourth resistor, and a third capacitor. The base of the transistor forms an input end and is connected to the low-pass filter circuit. The collector of the transistor is connected to a power supply. The emitter of the transistor is connected to the input end of the fourth resistor. The output end of the fourth resistor firstly serves as the output end of the emitter drive circuit and secondly is grounded through the third capacitor.

6. A transmitter driving circuit as claimed in claim 5, characterized in that: The capacity of the third capacitor is 10nF.

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