One-key multi-function switch control circuit for portable electronic devices

Abstract

The present invention relates to a switch control circuit, which includes a reset switch, a pulse generation circuit, an electronic switch circuit, a first delay switch circuit, and a second delay switch circuit. The electronic switch circuit includes a first switching transistor and a voltage dividing circuit. The voltage dividing output terminal of the voltage dividing circuit is connected to the gate of the first switching transistor, the input terminals are respectively connected to the power input terminal and the source of the first switching transistor, and the output terminal is grounded through the first delay switch circuit. The control signal input terminal of the first delay switch circuit is respectively connected to the output terminal of the second delay switch circuit and the drain of the first switching transistor, and is connected to the power input terminal through the reset switch. The input terminal of the second delay switch circuit is connected to the power input terminal through the reset switch, and the control signal input terminal is connected to the drain of the first switching transistor. Compared with the prior art, through the first delay switch circuit and the second delay switch circuit, in cooperation with the pulse generation circuit, the reset switch of the present invention can generate various signal combinations.

Description

Technical Field

[0001] The present invention relates to a switch control circuit, and more particularly to a one-button multi-function switch control circuit for portable electronic devices. Background Art

[0002] "One-button multi-function" means that a single switch can control multiple functions of a device. Portable electronic devices, especially those specifically used in the railway industry, cannot be powered by mains electricity outdoors, and the construction work hours are relatively long, and it may take an entire day to return to the construction site to recharge the battery. Therefore, it is required that portable electronic devices must ensure a full day's power supply. However, in order to meet the requirement of being lightweight, portable devices cannot be equipped with extra-large capacity batteries. So in actual use, the devices often run short of power, causing the devices to often "break down", and the current solution is only to carry enough spare batteries.

[0003] To solve the problem of "power shortage" of portable devices, in addition to selecting batteries with high capacity density, it is also necessary to reasonably arrange and manage the power consumption of the devices. During on-site construction, portable devices are often used frequently. However, due to the long start-up time of the devices and the need for complex operations such as initialization settings, users generally do not want to save power by frequently turning the devices on and off, resulting in the devices quickly running out of power and unable to continue using. Therefore, it is particularly necessary to make the operation of power management of portable devices easy and simple through optimized design. The present invention provides a switch control circuit that can control the on and off of the device power supply through a single switch button, and can also put some temporarily unnecessary functional circuits into "sleep" and "wake up" through it, so as to achieve the purpose of saving electric energy and extending the usage time of portable devices. Currently, the implementation of one-button multi-function mostly uses software control, and its reliability and effect are not as good as those achieved by hardware circuits. Summary of the Invention

[0004] The purpose of the present invention is to provide a one-button multi-function switch control circuit for portable electronic devices to overcome the defects of the above-mentioned prior art.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A switch control circuit includes a reset switch, a pulse generation circuit, an electronic switch circuit, a first delay switch circuit, and a second delay switch circuit. The electronic switch circuit includes a first switch tube and a voltage division circuit. The voltage division output terminal of the voltage division circuit is connected to the gate of the first switch tube, the input terminals are respectively connected to the power input terminal and the source of the first switch tube, and the output terminal is grounded through the first delay switch circuit. The control signal input terminal of the first delay switch circuit is respectively connected to the output terminal of the second delay switch circuit and the drain of the first switch tube, and is connected to the power input terminal through the reset switch. The input terminal of the second delay switch circuit is connected to the power input terminal through the reset switch, the control signal input terminal is connected to the drain of the first switch tube, the drain of the first switch tube is connected to a controlled device, and the input terminal of the pulse generation circuit is connected to the power input terminal, and the output terminal is connected to the controlled device.

[0007] The control circuit further includes an LED indicator light. One end of the LED indicator light is connected to the drain of the first switch tube, and the other end is grounded.

[0008] An eleventh resistor is provided between the LED indicator light and the drain of the first switch tube.

[0009] The first delay switch circuit includes a second switch tube and a first capacitor. The drain of the second switch tube is connected to the output terminal of the voltage division circuit, the source is grounded and connected to the negative electrode of the first capacitor, and the gate is connected to the power input terminal through the reset switch and is respectively connected to the positive electrode of the first capacitor and the drain of the first switch tube.

[0010] A third resistor is connected in parallel across both ends of the first capacitor. A tenth resistor is provided between the gate of the second switch tube and the drain of the first switch tube. A sixth diode and a ninth resistor are sequentially provided between the reset switch and the gate of the second switch tube.

[0011] The second delay switch circuit includes a third switch tube, a fourth switch tube, a second capacitor, and a third capacitor. The drain of the fourth switch tube is connected to the power input terminal through the reset switch, the source is connected to the gate of the third switch tube, the gate is connected to the drain of the first switch tube and is grounded through the third capacitor. The gate of the third switch is grounded through the second capacitor, the source is grounded, and the drain is connected to the gate of the second switch tube.

[0012] A fifth resistor is connected in parallel across both ends of the second capacitor. A fourth resistor is provided between the drain of the third switch and the positive electrode of the first capacitor. A fifth diode and a sixth resistor are provided between the gate of the fourth switch tube and the drain of the first switch tube. The fifth diode and the sixth resistor are connected in parallel with each other. A seventh resistor is provided between the drain of the fourth switch tube and the reset switch.

[0013] The reset switch is also grounded through an eighth resistor.

[0014] The pulse generating circuit includes a fourth capacitor, an eighth switching transistor, a ninth switching transistor, a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, and a twelfth diode. The gate of the eighth switching transistor is connected to the power input terminal through the reset switch and grounded through the thirteenth resistor. The source is grounded, and the drain is connected to the power input terminal through the fourteenth resistor and to the positive electrode of the fourth capacitor through the fifteenth resistor. The base of the ninth switching transistor is connected to the negative electrode of the fourth capacitor and the negative electrode of the twelfth diode. The emitter is at a very low potential, and the collector is connected to the controlled device and connected to a 5V power supply through a sixteenth resistor.

[0015] The voltage dividing circuit is composed of a first resistor and a second resistor connected in series.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1) Through the first delay switch circuit and the second delay switch circuit, a reset switch can control the on and off of the first switching transistor at the same time. Cooperating with the pulse generating circuit, the reset switch can generate a variety of signal combinations.

[0018] 2) By setting the LED indicator, after the first delay switch circuit takes effect, the conduction information of the first switching transistor can be fed back, so as to release the reset switch in time and avoid the second delay switch circuit from taking effect.

[0019] 3) The first delay switch circuit is obtained through the second switching transistor and the first capacitor, and the circuit structure is simple.

[0020] 4) The combination of the second delay switch circuit and the first delay circuit can avoid too fast state switching.

[0021] 5) The output of the drain of the first switching transistor can be used to keep the first delay switch circuit continuously conducting and lay a foundation for the second delay switch circuit to take effect. Description of the Drawings

[0022] Figure 1 It is a schematic structural diagram of an embodiment of the present invention;

[0023] Figure 2 It is a schematic structural diagram of the present invention;

[0024] Wherein: 1. Pulse generating circuit, 2. Electronic switch circuit, 3. Main control circuit, 4. Display, 5. Reader control board. Detailed Embodiment

[0025] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. This embodiment is implemented on the premise of the technical solution of the present invention, and the detailed implementation manners and specific operation processes are given, but the protection scope of the present invention is not limited to the following embodiments.

[0026] A switch control circuit, as Figure 2 shown, includes a reset switch S1, a pulse generation circuit 1, an electronic switch circuit 2, a first delay switch circuit, and a second delay switch circuit. Among them, the first delay switch circuit and the second delay switch circuit constitute a main control circuit 3. The electronic switch circuit 2 includes a first switch tube V1 and a voltage division circuit. The voltage division circuit is composed of a first resistor R1 and a second resistor R2 connected in series. The voltage division output end of the voltage division circuit is connected to the gate of the first switch tube V1, the input ends are respectively connected to the power input end and the source of the first switch tube V1, and the output end is grounded through the first delay switch circuit. The control signal input end of the first delay switch circuit is respectively connected to the output end of the second delay switch circuit and the drain of the first switch tube V1, and is connected to the power input end through the reset switch S1. The input end of the second delay switch circuit is connected to the power input end through the reset switch S1, the control signal input end is connected to the drain of the first switch tube V1, the drain of the first switch tube V1 is connected to the controlled device, the input end of the pulse generation circuit 1 is connected to the power input end, and the output end is connected to the controlled device.

[0027] Through the first delay switch circuit and the second delay switch circuit, a reset switch S1 can be used to control the on and off of the first switch tube V1 at the same time. Cooperating with the pulse generation circuit 1, the reset switch S1 can generate a variety of signal combinations.

[0028] The control circuit further includes an LED indicator light. One end of the LED indicator light is connected to the drain of the first switch tube V1, and the other end is grounded. By setting the LED indicator light, after the first delay switch circuit takes effect, the conduction information of the first switch tube V1 can be fed back, so as to release the reset switch S1 in time and avoid the second delay switch circuit from taking effect. An eleventh resistor R11 is provided between the LED indicator light and the drain of the first switch tube V1.

[0029] The first delay switch circuit includes a second switch tube V2 and a first capacitor C1. The drain of the second switch tube V2 is connected to the output end of the voltage division circuit, the source is grounded and connected to the negative electrode of the first capacitor C1, and the gate is connected to the power input end through the reset switch S1 and is respectively connected to the positive electrode of the first capacitor C1 and the drain of the first switch tube V1.

[0030] A third resistor R3 is connected in parallel across both ends of the first capacitor C1. A tenth resistor R10 is provided between the gate of the second switching transistor V2 and the drain of the first switching transistor V1. A sixth diode V6 and a ninth resistor R9 are successively provided between the reset switch S1 and the gate of the second switching transistor V2.

[0031] The second delay switching circuit includes a third switching transistor V3, a fourth switching transistor V4, a second capacitor C2, and a third capacitor C3. The drain of the fourth switching transistor V4 is connected to the power input terminal through the reset switch S1, the source is connected to the gate of the third switching transistor V3, the gate is connected to the drain of the first switching transistor V1, and is grounded through the third capacitor C3. The gate of the third switch is grounded through the second capacitor C2, the source is grounded, and the drain is connected to the gate of the second switching transistor V2.

[0032] A fifth resistor R5 is connected in parallel across both ends of the second capacitor C2. A fourth resistor R4 is provided between the drain of the third switch and the positive electrode of the first capacitor C1. A fifth diode V5 and a sixth resistor R6 are provided between the gate of the fourth switching transistor V4 and the drain of the first switching transistor V1. The fifth diode V5 and the sixth resistor R6 are connected in parallel. A seventh resistor R7 is provided between the drain of the fourth switching transistor V4 and the reset switch S1.

[0033] The reset switch S1 is also grounded through an eighth resistor R8.

[0034] The pulse generating circuit 1 includes a fourth capacitor C4, an eighth switching transistor V8, a ninth switching transistor V9, a thirteenth resistor R13, a fourteenth resistor R14, a fifteenth resistor R15, and a twelfth diode V10. The gate of the eighth switching transistor V8 is connected to the power input terminal through the reset switch S1 and is grounded through the thirteenth resistor R13. The source is grounded, and the drain is connected to the power input terminal through the fourteenth resistor R14 and is connected to the positive electrode of the fourth capacitor C4 through the fifteenth resistor R15. The base of the ninth switching transistor V9 is connected to the negative electrode of the fourth capacitor C4 and the negative electrode of the twelfth diode V10. The emitter is at a very low level, and the collector is connected to the controlled device and is connected to the 5V power supply through a sixteenth resistor R16.

[0035] The above circuit structure can be applied to various occasions. Taking the transponder message reader / writer as an example, the following is a detailed introduction. As Figure 1 shown, the collector of the ninth switching transistor V9 is connected to the display, and the drain of the first switching transistor V1 is connected to the reader / writer control board.

[0036] The above first switching transistor V1 is a high-power P-channel MOS transistor, and the model can be MTD2955. As a power switching switch, the power supply uses a 12V DC power supply. The drain of V1 is used as the power output terminal and is connected to the subsequent circuit of the device. A resistor R1 with a resistance value of 10K is connected across the S and G poles of V1, and then a resistor R2 with a resistance value of 10K is connected from the G pole to the drain of V2.

[0037] V4, V3, and V2 are three N-channel MOSFETs with a specification of 2N7002, and V8 is an N-channel MOSFET. In the above circuit, the models of the diodes V5, V6, V7, and V10 are all 1N4148, the model of the MOSFET V8 is 2N7002, the model of the triode V9 is 2N5551, the specifications of the electrolytic capacitors C1, C2, C3, and C4 are all 10u, and the resistors are all 0805 surface mount resistors.

[0038] The transponder message reader / writer is a portable device, and the battery should be constantly connected to the device. The reset button S1 is a normally open contact. Therefore, the working principle of the "one-button multi-function" switch control circuit of the portable electronic device is described in several cases:

[0039] 1) Before power-on: Since the reset switch S1 is in the open state, the positive pole of the battery (+12V) cannot reach the G pole of V8 through R12. Similarly, it cannot reach the D pole of V4 through R7, nor can it reach the G pole of V2 through V6 and R9. However, +12V can reach the G pole of V8 through R14, and at the same time, it can reach the ground through R15, C4, and the be of V9, thus forming a current loop to charge C4 until it is fully charged. During the charging process, there is current flowing through the base of V9 and it conducts, the potential of the c pole changes from high to low. After C4 is fully charged, the base current of V9 becomes zero and it cuts off, and the potential of the c pole returns to the high potential, that is, the ctrl terminal outputs a negative pulse. At this time, other circuits of the device have not been powered, so this pulse is invalid. +12V can also reach the G pole of V1 through R1 and then reach the D pole of V2 through R2. In this way, the MOSFETs V8, V4, V3, and V2 are all in the cut-off state because they do not meet the conduction conditions. Since V2 is cut off, V1 cannot obtain a negative bias voltage and cannot conduct, and the subsequent circuits of the device are in the shutdown state. Because the MOSFET has a gate insulation layer structure and the inter-pole is of high resistance, the power consumption of the whole machine is extremely small during standby, only a few uA of current, and it can be placed for a long time.

[0040] 2) Power on: The operator presses the S1 button (for about 2 seconds), +12V goes through R12 and R13 to the ground, and a forward voltage of about 6V is obtained at the G pole of V8, causing V8 to conduct. C4 starts to discharge through R15 and V10 until it is completely discharged. Since the base of V9 is always reverse-biased during the discharge process, V9 remains cut-off. When pressing the S1 button, +12V reaches the D pole of V4 through R7, and +12V also reaches the G pole of V2 through V6 and R9 to charge C1, causing the G pole voltage to gradually rise from zero and making the D pole of V3 obtain the same voltage through R4. When the voltage exceeds the conduction voltage of V2, V2 conducts, grounding one end of R2, causing the G pole voltage of V1 to drop from +12V to about 6V, making V1 conduct due to obtaining a bias voltage, turning on the electronic switch to output +12V, the indicator light emits light, and the subsequent circuits of the device start to work. After the operator sees the indicator light on or the screen starts, release the button S1. The output +12V is connected to the G pole of V2 through R10 to maintain the conducting state of V1. The output +12V also charges C3 through R6, causing the G pole voltage of V4 to gradually rise to +12V, exceeding the conduction voltage of V4. However, at this time, the S1 button has been released and there is no voltage at the D pole of V4, so V4 still cannot conduct, only providing a preparation condition for the device to shut down. Releasing the button S1 also causes V8 to turn off due to the loss of the G pole voltage. +12V starts to charge C4 through R14 and R15 until it is full. V9 outputs a negative pulse to the display circuit. Since the device is still in the startup mode, this negative pulse has no effect.

[0041] 3) Sleep and wake-up: After the device is powered on, when a test is completed and there is still some time before the next test, in order to save power, it is often required to turn off the display screen and some circuits, which is called sleep. The device's sleep operation requires clicking the button (press and release) S1 once. Since the switch control circuit takes a relatively long time (about 2 seconds) to take effect, we only analyze the principle of the display control circuit. When clicking the S1 button, +12V quickly reaches the G pole of V8 through R12 to make it conduct, and C4 quickly discharges. At this time, V9 remains cut-off. After quickly releasing the S1 button, V8 changes from conducting to cut-off, C4 starts to charge and gradually becomes full. After V9 conducts and then turns off, it outputs a negative pulse to trigger circuits such as the display screen to achieve sleep. When a new test is needed, click the button S1 again to wake up the sleeping circuit. Similarly, V9 outputs another negative pulse to complete the wake-up operation of the device.

[0042] 4) Shutdown: When the device is not needed for a short period of time, shut it down. When shutting down, the operator presses the S1 button (about 2 seconds), and +12V reaches the D pole of V4 through R7. Since the G pole voltage of V4 is already high when it is turned on, V4 is turned on, and +12V charges C2 through R7, causing the G pole voltage of V3 to gradually rise. When it exceeds the V3 conduction voltage, V3 is turned on to quickly lower the G pole voltage of V2, and V2 is cut off, while the G pole voltage of V1 is quickly raised to +12V, V1 loses bias and is cut off, the output voltage is quickly cut off, and the device stops working. When the S1 button is released, C1 discharges the residual voltage through R3, C2 discharges the electricity through R5, and C3 discharges the electricity through V5, R11, and LED. At this point, the circuit returns to the state before the power-on.

Claims

1. A switch control circuit, characterized in that, It includes a reset switch, a pulse generating circuit, an electronic switch circuit, a first delay switch circuit and a second delay switch circuit. The electronic switch circuit includes a first switching transistor and a voltage dividing circuit. The voltage dividing output terminal of the voltage dividing circuit is connected to the gate of the first switching transistor, the input terminals are respectively connected to the power input terminal and the source of the first switching transistor, and the output terminal is grounded through the first delay switch circuit. The control signal input terminal of the first delay switch circuit is respectively connected to the output terminal of the second delay switch circuit and the drain of the first switching transistor, and is connected to the power input terminal through the reset switch. The input terminal of the second delay switch circuit is connected to the power input terminal through the reset switch, and the control signal input terminal of the second delay switch circuit is connected to the drain of the first switching transistor. The drain of the first switching transistor is connected to a controlled device. The input terminal of the pulse generating circuit is connected to the power input terminal, and the output terminal is connected to the controlled device.

2. The switching control circuit according to claim 1, wherein The control circuit further includes an LED indicator light. One end of the LED indicator light is connected to the drain of the first switching transistor, and the other end is grounded.

3. The switching control circuit according to claim 2, wherein An eleventh resistor is provided between the LED indicator light and the drain of the first switching transistor.

4. A switch control circuit according to claim 1, wherein, The first delay switch circuit includes a second switching transistor and a first capacitor. The drain of the second switching transistor is connected to the output terminal of the voltage dividing circuit, the source is grounded and is connected to the negative electrode of the first capacitor, and the gate is connected to the power input terminal through the reset switch and is respectively connected to the positive electrode of the first capacitor and the drain of the first switching transistor.

5. The switching control circuit according to claim 4, characterized in that, A third resistor is connected in parallel across both ends of the first capacitor. A tenth resistor is provided between the gate of the second switching transistor and the drain of the first switching transistor. A sixth diode and a ninth resistor are sequentially provided between the reset switch and the gate of the second switching transistor.

6. The switching control circuit according to claim 4, characterized in that, The second delay switch circuit includes a third switching transistor, a fourth switching transistor, a second capacitor and a third capacitor. The drain of the fourth switching transistor is connected to the power input terminal through the reset switch, the source is connected to the gate of the third switching transistor, the gate is connected to the drain of the first switching transistor and is grounded through the third capacitor. The gate of the third switch is grounded through the second capacitor, the source is grounded, and the drain is connected to the gate of the second switching transistor.

7. The switching control circuit according to claim 6, wherein, A fifth resistor is connected in parallel across both ends of the second capacitor. A fourth resistor is provided between the drain of the third switch and the positive electrode of the first capacitor. A fifth diode and a sixth resistor are provided between the gate of the fourth switching transistor and the drain of the first switching transistor. The fifth diode and the sixth resistor are connected in parallel with each other. A seventh resistor is provided between the drain of the fourth switching transistor and the reset switch.

8. A switch control circuit according to claim 6, characterized in that, The reset switch is further grounded through an eighth resistor.

9. A switch control circuit according to claim 1, characterized in that, The pulse generating circuit includes a fourth capacitor, an eighth switching transistor, a ninth switching transistor, a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, and a twelfth diode. The gate of the eighth switching transistor is connected to the power input terminal through the reset switch and grounded through the thirteenth resistor. The source is grounded, and the drain is connected to the power input terminal through the fourteenth resistor and to the positive electrode of the fourth capacitor through the fifteenth resistor. The base of the ninth switching transistor is connected to the negative electrode of the fourth capacitor and the negative electrode of the twelfth diode. The emitter is at a very low level, and the collector is connected to the controlled device and connected to the 5V power supply through a sixteenth resistor.

10. A switch control circuit according to claim 1, characterized in that, The voltage dividing circuit is composed of a first resistor and a second resistor connected in series.

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