CMOS Switch Trigger Circuit

Abstract

The present invention provides a CMOS switch triggering circuit, comprising: a light sensing unit, which includes a photodiode, a first MOS transistor, a second MOS transistor, a third MOS transistor, a capacitor and a voltage processing module, and is used for sensing a light signal and converting the sensed light signal into an electrical signal for output; a control switch, connected to the electrical signal output end of the light sensing unit, and triggering the disconnection or closure of a subsequent circuit according to the output electrical signal. The present invention is implemented by adopting a CMOS process for the overall circuit, and the circuit structure is simple and reliable; the photosensitive element uses an environmentally friendly silicon material, avoiding the use of photosensitive materials composed of heavy metals.

Description

Technical Field

[0001] The present invention relates to the field of switching circuits, and in particular to a CMOS switch trigger circuit. Background Art

[0002] Currently, most urban street lights adopt automatic control devices to control the automatic turning on or off of street lights. Common automatic control methods for street lights are: photoresistor + relay or photoresistor + triode.

[0003] The photoresistor is used as a light intensity sensor. When the light intensity changes, the resistance value of the photoresistor also changes accordingly, thereby controlling the opening and closing of the relay to achieve the purpose of controlling the street light.

[0004] Currently, common photoresistor materials include cadmium sulfide, cadmium selenide, lead sulfide, etc. Cadmium is a rare element and a toxic heavy metal with a small content in nature, and lead is a toxic heavy metal; when the environment is polluted by cadmium and lead, cadmium and lead can accumulate in organisms and enter the human body through the food chain, causing chronic poisoning.

[0005] Therefore, it is necessary to design an environmentally friendly switch trigger circuit. Summary of the Invention

[0006] The purpose of the present invention is to provide a CMOS switch trigger circuit for realizing the switch trigger function and being environmentally friendly.

[0007] Based on the above considerations, the present invention provides a CMOS switch trigger circuit, including:

[0008] A light sensing unit, the light sensing unit includes a photodiode, a first MOS transistor, a second MOS transistor, a third MOS transistor, a capacitor and a voltage processing module, and the light sensing unit is used to sense a light signal and convert the sensed light signal into an electrical signal for output;

[0009] A control switch, connected to the electrical signal output end of the light sensing unit, and triggering the disconnection or closing of the subsequent circuit according to the output electrical signal.

[0010] Optionally, the first MOS transistor, the second MOS transistor, and the third MOS transistor are all NMOS transistors. The source of the first MOS transistor is connected to the photodiode, the drain is connected to the first end of the capacitor, and the gate is connected to the first signal input terminal. The first signal input terminal controls the switch of the gate of the first MOS transistor; the second end of the capacitor is grounded; the source of the second MOS transistor is connected to the first end of the capacitor, the drain is connected to the control voltage input terminal, and the gate is connected to the second signal input terminal; the gate of the third MOS transistor is connected to the first end of the capacitor, the drain is connected to the power supply voltage input terminal, and the source is connected to the voltage processing module; the voltage processing module obtains the source output voltage of the third MOS transistor at different times and calculates the voltage difference at different times.

[0011] Optionally, the capacitor is a floating diffusion capacitor.

[0012] Optionally, the third MOS transistor is a source follower transistor.

[0013] Optionally, the control switch has multiple gears, and corresponding gears are triggered according to the voltage difference output by the voltage processing module to achieve multi-stage control or stepless continuous control of the switch.

[0014] Optionally, the operation method of the switch trigger circuit includes:

[0015] Control the control voltage input terminal of the drain of the second MOS transistor to be at a low level, the second signal input terminal to be at a high level, the second MOS transistor to conduct, and the voltage at the first end of the capacitor to become low level. At the same time, the photodiode collects light and is in an integration state;

[0016] After the integration of the photodiode is completed, the photo-generated charge is read out. Control the drain voltage input terminal of the second MOS transistor to be at a high level. The photodiode is in a signal readout state, the second MOS transistor conducts, and the voltage at the drain of the second MOS transistor is transmitted to the first end of the capacitor. Then, the second MOS transistor is turned off, and the source output voltage V0 of the third MOS transistor is read;

[0017] Turn on the first MOS transistor to transfer the photo-generated charge in the photodiode to the first end of the capacitor. The source output voltage of the third MOS transistor decreases as the photo-generated charge is transferred. After stabilization, the source output voltage V1 of the third MOS transistor is read;

[0018] The voltage processing module calculates the obtained source output voltage to obtain the voltage difference △V, that is, △V = V0 - V1;

[0019] The control switch controls the disconnection or closure of the subsequent circuit according to the voltage difference △V obtained by the voltage processing module.

[0020] Optionally, before the photodiode collects light, the second signal input terminal and the drain voltage input terminal of the second MOS transistor are controlled to be at a high level to turn on the second MOS transistor, and the input voltage at the drain of the second MOS transistor is transmitted to the first end of the capacitor; then the first signal input terminal of the first MOS transistor is controlled to be at a high level to turn on the first MOS transistor, and the charges in the photodiode are transferred to the capacitor to clear the charges in the photodiode.

[0021] Optionally, the circuit is applied to the control of street lights, and according to whether there is light during the day or at night, it triggers the automatic closing or opening of the street light switch, thereby realizing the automatic control of the street lights.

[0022] The present invention provides a CMOS switch trigger circuit, which has the following beneficial effects:

[0023] The overall circuit is implemented using CMOS technology, and the circuit structure is simple and reliable;

[0024] The photosensitive element uses environmentally friendly silicon materials, avoiding the use of photosensitive materials composed of heavy metals. Description of the Drawings

[0025] Other features, objects, and advantages of the present invention will become more apparent by reading the following detailed description of non-limiting embodiments with reference to the accompanying drawings.

[0026] Figure 1 It shows a schematic diagram of the CMOS switch trigger circuit provided by the present invention.

[0027] In the figure, throughout different drawings, the same or similar reference numerals represent the same or similar devices (modules) or steps. Detailed Embodiments

[0028] Many specific details are set forth in the following description in order to provide a thorough understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar generalizations without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0029] Secondly, the present invention is described in detail using schematic diagrams. When detailing the embodiments of the present invention, for the sake of illustration, the schematic diagrams are only examples and should not limit the scope of protection of the present invention herein.

[0030] The present invention provides a CMOS switch trigger circuit, including:

[0031] A light sensing unit, which includes a photodiode, a first MOS transistor, a second MOS transistor, a third MOS transistor, a capacitor, and a voltage processing module. The light sensing unit is used to sense a light signal and convert the sensed light signal into an electrical signal for output.

[0032] A control switch, connected to the electrical signal output terminal of the light sensing unit, triggers the opening or closing of the subsequent circuit according to the output electrical signal. It is used to control the subsequent circuit.

[0033] To make the above objects, features, and advantages of the present invention more obvious and understandable, the technical solutions of the present invention will be described in detail below with reference to the accompanying drawings.

[0034] The present invention provides a CMOS switch triggering circuit, as Figure 1 shown, including:

[0035] A light sensing unit, which includes a photodiode PD, a first MOS transistor T1, a second MOS transistor T2, a third MOS transistor T3, a capacitor C1, and a voltage processing module. The light sensing unit 10 is used to sense a light signal and convert the sensed light signal into an electrical signal for output.

[0036] A control switch, connected to the electrical signal output terminal of the light sensing unit, triggers the opening or closing of the subsequent circuit according to the output electrical signal.

[0037] In this embodiment, the first MOS transistor T1, the second MOS transistor T2, and the third MOS transistor T3 are all NMOS transistors. The source of the first MOS transistor T1 is connected to the photodiode PD, the drain is connected to the first end of the capacitor C1, the gate is connected to the first signal input terminal G1, and the first signal input terminal G1 controls the switch of the gate of the first MOS transistor T1; the second end of the capacitor C1 is grounded; the source of the second MOS transistor T2 is connected to the first end of the capacitor C1, the drain is connected to the control voltage input terminal Vk, and the gate is connected to the second signal input terminal G2; the gate of the third MOS transistor T3 is connected to the first end of the capacitor C1, the drain is connected to the power supply voltage input terminal VDD, and the source is connected to the voltage processing module; the voltage processing module obtains the source output voltage V of the third MOS transistor T3 at different times and calculates the voltage difference △V at different times.

[0038] The capacitor C1 is a floating diffusion capacitor, and the third MOS transistor T3 is a source follower transistor. The voltage processing module includes a comparator circuit, a Ramp circuit (generating the ramp signal required for the comparator to compare), and a calculator, etc.

[0039] The operation method of the switch triggering circuit provided by the present invention includes:

[0040] Control the drain control voltage input terminal Vk of the second MOS transistor T2 to be at a low level, the second signal input terminal G2 to be at a high level, the second MOS transistor T2 to conduct, and the voltage at the first terminal of the capacitor C1 to become low. At the same time, the photodiode PD collects light and is in an integration state;

[0041] After the photodiode PD finishes integrating and reads out the photo-generated charges, control the drain control voltage input terminal Vk of the second MOS transistor T2 to be at a high level. The photodiode PD is in a signal readout state, the second MOS transistor T2 conducts, and the voltage at the drain of the second MOS transistor T2 is transmitted to the first terminal of the capacitor C1. Then turn off the second MOS transistor T2 and read the source output voltage V0 of the third MOS transistor T3;

[0042] Turn on the first MOS transistor T1 to transfer the photo-generated charges in the photodiode PD to the first terminal of the capacitor C1. The source output voltage of the third MOS transistor T3 decreases as the photo-generated charges are transferred. After stabilization, read the source output voltage V1 of the third MOS transistor T3;

[0043] The voltage processing module calculates the obtained source output voltage to obtain the voltage difference △V, that is, △V = V0 - V1;

[0044] The control switch controls the opening or closing of the subsequent circuit according to the voltage difference △V obtained by the voltage processing module.

[0045] The control switch is provided with multiple gears. Triggering the corresponding gear according to the voltage difference △V output by the voltage processing module can achieve multi-stage control or stepless continuous control of the switch.

[0046] Optionally, before the photodiode PD collects light, the second signal input terminal G2 and the drain voltage input terminal of the second MOS transistor T2 can also be controlled to be at a high level to make the second MOS transistor T2 conduct, and the input voltage at the drain of the second MOS transistor T2 is transmitted to the first terminal of the capacitor C1; then control the first signal input terminal G1 of the first MOS transistor T1 to be at a high level to make the first MOS transistor T1 conduct, and the charges in the photodiode PD are transferred to the capacitor C1 to clear the charges in the photodiode PD.

[0047] The CMOS switch trigger circuit provided by the present invention can be applied to the control of street lights. According to whether there is light during the day or at night, it triggers the automatic closing or opening of the street light switch, thereby realizing the automatic control of the street lights. For example, when the voltage difference △V is less than a certain set value Vm, the signal given at this time represents no light, that is, at night, the control switch turns on switch K1, and at this time the street light is lit with a brightness of L1; when Vm + 0.3 > △V ≥ Vm, the control switch turns on switch K2, and at this time the brightness is L2; when Vm + 0.6 > △V ≥ Vm + 0.3, the control switch turns on switch K3, and at this time the brightness of the street light is L3; when Vm + 1.1 > △V ≥ Vm + 0.6, the control switch turns on switch K4, and at this time the brightness of the street light is L4; when △V ≥ Vm + 1.1, the signal at this time represents the light state, that is, during the day, the control switch is completely turned off to turn off the street light. Among them, the brightness of the street lights L1 > L2 > L3 > L4. It should be noted that switches K1, K2, K3, and K4 can be different relays or other circuit devices, so as to achieve multi-level control of the switch. Of course, the control switch can also be set to countless gears to achieve stepless continuous control of the switch.

[0048] In other embodiments, the operation time of the CMOS switch trigger circuit of the present invention can also be limited. In order to reduce the number of operations, within a period of time when the street light changes from the lit state to the off state or from the off state to the lit state, that is, within a period of time when it completely changes from night to day or from day to night, the circuit operation can be not performed or performed at a longer interval to reduce the number of operations.

[0049] The CMOS switch trigger circuit provided by the present invention can be applied to ambient brightness feedback. According to the different voltage differences △V, it triggers the corresponding switch, thereby reflecting different light intensities in the environment.

[0050] It should be noted that the CMOS switch trigger circuit provided by the present invention can also be used in other light detection circuits or light trigger circuits, which are not limited here.

[0051] In summary, the present invention provides a CMOS switch trigger circuit, including: a light sensing unit, the light sensing unit includes a photodiode, a first MOS transistor, a second MOS transistor, a third MOS transistor, a capacitor and a voltage processing module, and the light sensing unit is used to sense the light signal and convert the sensed light signal into an electrical signal for output; a control switch, connected to the electrical signal output end of the light sensing unit, and triggers the disconnection or closing of the subsequent circuit according to the output electrical signal. The overall circuit is implemented using CMOS technology, and the circuit structure is simple and reliable; the photosensitive element uses environmentally friendly silicon materials, avoiding the use of photosensitive materials composed of heavy metals.

[0052] It is obvious to those skilled in the art that the present invention is not limited to the details of the above-described exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, in any case, the embodiments should be regarded as exemplary and non-limiting. In addition, obviously, the word "including" does not exclude other elements and steps, and the term "a" does not exclude a plurality. A plurality of elements recited in the apparatus claims can also be implemented by one element. Words such as first, second, etc. are used to denote names and do not denote any particular order.

Claims

1. A CMOS switch trigger circuit, characterized in that, Comprising: A light sensing unit, the light sensing unit includes a photodiode, a first MOS transistor, a second MOS transistor, a third MOS transistor, a capacitor and a voltage processing module, and the light sensing unit is used to sense a light signal and convert the sensed light signal into an electrical signal for output; A control switch, connected to the electrical signal output end of the light sensing unit, and triggering the disconnection or closure of the subsequent circuit according to the output electrical signal; The first MOS transistor, the second MOS transistor and the third MOS transistor are all NMOS transistors. The source electrode of the first MOS transistor is connected to the photodiode, the drain electrode is connected to the first end of the capacitor, and the gate electrode is connected to the first signal input end. The first signal input end controls the switch of the gate electrode of the first MOS transistor; the second end of the capacitor is grounded; the source electrode of the second MOS transistor is connected to the first end of the capacitor, the drain electrode is connected to the control voltage input end, and the gate electrode is connected to the second signal input end; the gate electrode of the third MOS transistor is connected to the first end of the capacitor, the drain electrode is connected to the power supply voltage input end, and the source electrode is connected to the voltage processing module; the voltage processing module obtains the source output voltage of the third MOS transistor at different times and calculates the voltage difference at different times.

2. The CMOS switch trigger circuit according to claim 1, wherein The capacitor is a floating diffusion capacitor.

3. The CMOS switch trigger circuit according to claim 1, wherein The third MOS transistor is a source follower transistor.

4. The CMOS switch trigger circuit according to claim 1, wherein The control switch is provided with multiple gears, and triggers the corresponding gear according to the voltage difference output by the voltage processing module to realize multi-stage control or stepless continuous control of the switch.

5. The CMOS switch trigger circuit according to claim 1, wherein The operation method of the switch trigger circuit includes: Controlling the control voltage input end of the drain electrode of the second MOS transistor to be at a low level, the second signal input end to be at a high level, the second MOS transistor to be turned on, the voltage at the first end of the capacitor to become low level. At the same time, the photodiode collects light and is in an integration state; After the photodiode finishes integrating, read out the photo-generated charge, control the drain voltage input end of the second MOS transistor to be at a high level, the photodiode is in a signal readout state, the second MOS transistor is turned on, the voltage at the drain electrode of the second MOS transistor is transmitted to the first end of the capacitor, and then turn off the second MOS transistor, and read the source output voltage V0 of the third MOS transistor; Turn on the first MOS transistor, transfer the photo-generated charge in the photodiode to the first end of the capacitor, the source output voltage of the third MOS transistor decreases as the photo-generated charge is transferred, and after stabilization, read the source output voltage V1 of the third MOS transistor; The voltage processing module calculates the obtained source output voltage to obtain a voltage difference △V, △V = V0 - V1; The control switch controls the disconnection or closure of the subsequent circuit according to the voltage difference △V obtained by the voltage processing module.

6. The CMOS switch trigger circuit according to claim 5, wherein Before the photodiode collects light, control the second signal input end and the drain voltage input end of the second MOS transistor to be at a high level to turn on the second MOS transistor, and the input voltage at the drain electrode of the second MOS transistor is transmitted to the first end of the capacitor; then control the first signal input end of the first MOS transistor to be at a high level to turn on the first MOS transistor, and the charge in the photodiode is transferred to the capacitor to clear the charge in the photodiode.

7. The CMOS switch trigger circuit according to any one of claims 1 to 6, characterized in that The circuit is applied to the control of street lights. According to whether there is light during the day or at night, it triggers the automatic closing or opening of the street light switch.

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