Constant current zero power consumption bistable circuit and control method

Abstract

The present invention proposes a constant current zero power consumption bistable circuit and control method, comprising: a control arm, a load arm and a feedback control bridge between the two arms arranged between a power supply and a ground; the control arm comprises a start branch, a hold branch and a discharge branch; the start branch is used to charge a capacitor C1; the hold branch, the discharge branch, the feedback control bridge and the load arm all comprise a switch tube; the capacitor C1 is used as a control switch of the switch tube Q2 of the feedback control bridge via a contact switch; the switch tube Q2 of the feedback control bridge is used as a control switch of the switch tube Q3 of the hold branch and the switch tube Q4 of the load arm; the switch tube Q3 of the hold branch is used as a control switch of the switch tube Q1 of the discharge branch; the discharge branch is used to discharge the capacitor C1; the switch tube Q2 and the switch tube Q3 form a self-locking. It only uses the most basic electronic components such as resistors, triodes, capacitors, etc., that is, it realizes the effect of constant current zero power consumption bistable at a low cost.

Description

Technical Field

[0001] The present invention relates to the field of electronic circuits, and in particular to a constant current zero power consumption bistable circuit and a control method. Background Art

[0002] If the existing power switch circuit is to achieve constant current and bistable output, it generally requires a more complex circuit structure and even the use of a control chip. Because these functional devices will inevitably generate power consumption, it is almost impossible to achieve zero power consumption to maximize energy saving and consumption reduction. Summary of the invention

[0003] In view of the defects and shortcomings of the prior art, the present invention proposes a constant current zero power consumption bistable circuit and a control method, which achieves the constant current zero power consumption bistable effect at low cost by only using the most basic electronic components such as resistors, transistors, capacitors, etc., and further introduces functions such as preventing excessive current and automatic shutdown due to low power in the preferred scheme.

[0004] The specific technical solutions are as follows:

[0005] A constant current zero power consumption bistable circuit, characterized by comprising: a control arm arranged between a power supply and a ground, a load arm and a feedback control bridge between the two arms;

[0006] The control arm includes a starting branch, a holding branch and a discharging branch;

[0007] The start-up branch is used to charge the capacitor C1; the holding branch, the discharge branch, the feedback control bridge and the load arm all include a switch tube;

[0008] The capacitor C1 is used as a control switch of the switch tube Q2 of the feedback control bridge through a contact switch; the switch tube Q2 of the feedback control bridge is used as a control switch of the switch tube Q3 of the holding branch and the switch tube Q4 of the load arm; the switch tube Q3 of the holding branch is used as a control switch of the switch tube Q1 of the discharge branch; the discharge branch is used to discharge the capacitor C1; and the switch tube Q2 and the switch tube Q3 are self-locking.

[0009] Preferably, the starting branch includes a resistor R1, a resistor R2 and a capacitor C1 connected in series; one end of the capacitor C1 is grounded, and the other end is connected to one end of the contact switch;

[0010] The holding branch includes a switch tube Q3, a resistor R5 and a resistor R8 connected to each other; the switch tube Q3 is a PNP type triode, the emitter is connected to the power supply, and the collector is connected to the resistor R5; the resistor R8 is grounded; the other end of the contact switch is connected between the resistor R5 and the resistor R8;

[0011] The discharge branch includes a switch tube Q1 and a resistor R3; the switch tube Q1 is an NPN type triode, the base is connected to the collector of the switch tube Q3 via the resistor R3, the collector is connected between the resistor R1 and the resistor R2, and the emitter is grounded;

[0012] The switch tube Q4 used in the load arm is a PNP type triode, the emitter of which is connected to the power supply, and the collector is grounded through a resistor R16 and serves as a port for connecting the load;

[0013] The feedback control bridge includes a resistor R15, a resistor R10 and a switch tube Q2 connected in series; the switch tube Q2 is an NPN type triode, the emitter is grounded, the collector is connected to the resistor R10, and the base is connected between the resistor R5 and the resistor R8 through the resistor R7; the other end of the resistor R10 is connected to the base of the switch tube Q3 and the switch tube Q4 through the resistor R9 and the resistor R13 respectively.

[0014] Preferably, the contact switch is connected in parallel with a capacitor C2.

[0015] Preferably, a first protection circuit is connected in parallel at both ends of the resistor R5; the first protection circuit includes: a resistor R4, a resistor R6, an NPN transistor Q5 and an NPN transistor Q6; the collector of the NPN transistor Q5 is connected to the collector of the switch tube Q3, the base is connected to the collector of the NPN transistor Q6, and the emitter is connected to the base of the NPN transistor Q6; the emitter of the NPN transistor Q6 is connected to the contact switch; the resistor R4 is connected in parallel with the collector and base of the NPN transistor Q5; the resistor R6 is connected in parallel with the base and emitter of the NPN transistor Q6;

[0016] A second protection circuit is connected in parallel at both ends of the resistor R10; the second protection circuit includes: a resistor R12, a resistor R14, an NPN transistor Q7 and an NPN transistor Q8; the collector of the NPN transistor Q7 is connected between the resistor R9 and the resistor R15 via the resistor R14, the base and the collector of the NPN transistor Q8 are connected between the resistor R9 and the resistor R15, and the emitter is connected to the base of the NPN transistor Q8; the emitter of the NPN transistor Q8 is connected to the collector of the switch tube Q2; the resistor R12 is connected in parallel with the base and emitter of the NPN transistor Q8;

[0017] A third protection circuit is arranged between the switch tube Q2 and the ground; the third protection circuit comprises: an NPN transistor Q11 and a resistor R11; the collector and base of the NPN transistor Q11 are respectively connected to the base and emitter of the switch tube Q2, and the emitter is grounded; one end of the resistor R11 is connected to the emitter of the switch tube Q2, and the other end is grounded.

[0018] Preferably, a low voltage shutdown circuit is connected in parallel at both ends of the resistor R16; the low voltage shutdown circuit includes: resistor R18, resistor R19, resistor R20, resistor R21, resistor R22, NPN transistor Q9, NPN transistor Q10 and temperature drift compensation diode D1; the collector and base of the NPN transistor Q9 are connected to the collector of the switch tube Q4 through resistor R21 and resistor R22 respectively, and the emitter is grounded through resistor R19; the emitter of the NPN transistor Q10 is grounded, the base is connected to the collector of the NPN transistor Q9, and the collector is connected to the end of the contact switch away from the capacitor C1; the temperature drift compensation diode D1 is connected to the base of the NPN transistor Q9, and is connected in series with the resistor R18 and the resistor R20 and then grounded.

[0019] And the control method according to the above constant current zero power consumption bistable circuit is characterized by:

[0020] In the initial state of connecting to the power supply, only the start-up branch is turned on, the bases of the switch tubes of the load arm, the feedback control bridge, the holding branch and the discharge branch are all at 0 potential, and the capacitor C1 is charged to a saturated state;

[0021] The contact switch is then used to switch between the following two states:

[0022] State 1: The switch tubes of the feedback control bridge and the discharge branch are turned on by the potential difference provided by the capacitor C1, so that the holding branch and the load arm are turned on; the capacitor C1 is discharged by the discharge branch;

[0023] State 2: The switch tube of the feedback control bridge is controlled by the capacitor C1 to be powered off and return to the cut-off state, so that the holding branch, the load arm and the discharge branch are turned off, and the starting branch is turned on.

[0024] Preferably, when the power supply voltage is lower than a set threshold, the low voltage shutdown circuit turns off the switch tube of the feedback control bridge.

[0025] The present invention and its preferred solution achieve the effect of constant current zero power consumption bistable state at low cost by only using the most basic electronic components such as resistors, triodes, capacitors, etc. without using a controller, and it is low-cost, simple to operate, and has stable performance. In the preferred solution, simple devices are also used to further introduce functions such as preventing excessive current and automatic shutdown due to low power, which further ensures the working stability of the overall circuit, so that the load and power supply can always maintain a good working state. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0027] Figure 1 This is a schematic diagram of the circuit principle of the first embodiment of the present invention;

[0028] Figure 2 This is a schematic diagram of the circuit principle of the second embodiment of the present invention. DETAILED DESCRIPTION

[0029] In order to make the features and advantages of this patent more obvious and easy to understand, the following embodiments are specifically described in detail with the accompanying drawings as follows:

[0030] like Figure 1 As shown, in the first embodiment of the present invention, a constant current zero power consumption bistable power switch circuit is designed to be implemented, which functionally includes:

[0031] A control arm, a load arm and a feedback control bridge are arranged between the power supply and the ground.

[0032] The control arm includes a starting branch, a holding branch and a discharging branch.

[0033] The start-up branch is used to charge the capacitor C1; the holding branch, the discharge branch, the feedback control bridge and the load arm all include a switch tube (i.e., a triode. In this embodiment, generally only the cut-off and saturation working states of the triode are used).

[0034] In this embodiment, capacitor C1 is used as the control switch of switch tube Q2 of feedback control bridge through contact switch, which is realized by controlling the voltage between the two ends of resistor R8, that is, the base and emitter of switch tube Q2. As long as the switch tube works in the cut-off region or saturation region, the on-off of switch tube Q2 can be controlled. Similarly, switch tube Q2 of feedback control bridge is used as the control switch of switch tube Q3 of holding branch and switch tube Q4 of load arm. As long as switch tube Q2 is turned on, voltage drop is generated across resistor R15, so that Q3 and Q4 are turned on. Switch tube Q3 of holding branch is further used as the control switch of switch tube Q1 of discharge branch. Discharge branch is used to discharge capacitor C1, so as to prepare for the shutdown of the whole circuit.

[0035] In particular, in the circuit designed in this embodiment, a self-locking relationship is formed between the switch tube Q2 and the switch tube Q3. When Q2 controls Q3 to be turned on, a stable voltage drop can be formed across the resistor R8 located in the holding branch, which in turn maintains the conduction of the switch tube Q2. This is also one of the key points that the present embodiment can achieve stable state switching through the contact switch.

[0036] like Figure 1 As shown, specifically, the starting branch includes a resistor R1, a resistor R2 and a capacitor C1 connected in series; one end of the capacitor C1 is grounded, and the other end is connected to one end of the contact switch;

[0037] The holding branch includes a switch tube Q3, a resistor R5 and a resistor R8 connected to each other; the switch tube Q3 is a PNP type triode, the emitter is connected to the power supply, and the collector is connected to the resistor R5; the resistor R8 is grounded; the other end of the contact switch is connected between the resistor R5 and the resistor R8;

[0038] The discharge branch includes a switch tube Q1 and a resistor R3; the switch tube Q1 is an NPN type triode, the base of which is connected to the collector of the switch tube Q3 via the resistor R3, the collector is connected between the resistor R1 and the resistor R2, and the emitter is grounded;

[0039] The switch tube Q4 used in the load arm is a PNP type triode, the emitter is connected to the power supply, and the collector is grounded through the resistor R16 and serves as a port for connecting the load;

[0040] The feedback control bridge includes a resistor R15, a resistor R10 and a switch tube Q2 connected in series; the switch tube Q2 is an NPN type triode, the emitter is grounded, the collector is connected to the resistor R10, and the base is connected between the resistor R5 and the resistor R8 through the resistor R7; the other end of the resistor R10 is connected to the base of the switch tube Q3 and the switch tube Q4 through the resistor R9 and the resistor R13 respectively.

[0041] According to the above circuit structure, in the initial state of power supply, only the starting branch is turned on, and the bases of the switch tubes of the load arm, feedback control bridge, holding branch and discharge branch are all at 0 potential, so that each switch tube works in the cut-off state, which is equivalent to the corresponding branch being disconnected. At this time, capacitor C1 is charged to a saturation state in a very short time (this process can be approximately equal to zero power consumption due to its extremely small power consumption).

[0042] The contact switch can then be used to switch between the following two states:

[0043] State 1: In the initial state, when the contact switch is pressed for the first time, nodes A and B are connected. At this time, the potential difference provided by capacitor C1 is applied to both ends of resistor R8. As long as the resistance value of the resistor is set reasonably, the switch tube Q2 can be turned on by the potential difference provided by capacitor C1 and enter the saturation zone.

[0044] At this time, due to the conduction of the feedback control bridge branch, a voltage drop occurs across the resistor R15. As long as it is greater than the built-in threshold of the transistor device, the switch tubes in the holding branch and the load arm can be turned on.

[0045] In this way, the load arm can output power to the load, and in the control arm, due to the self-locking relationship between the switch tubes Q2 and Q3, the conduction of Q3 in turn ensures that the switch tube Q2 can obtain a stable conduction voltage drop (across the resistor R8). On the other hand, the conduction of the switch tube Q3 also enables the switch tube Q1 to be turned on, which is equivalent to short-circuiting the two ends of the capacitor C1, discharging it and returning to the initial state.

[0046] During this process, the circuit provided by this embodiment maintains zero power consumption.

[0047] State 2: In state 1, if the contact switch is pressed again, the discharged capacitor C1 is equivalent to a short circuit to the resistor R8 in a short time, that is, the conduction state of the switch tube Q2 of the key feedback control bridge is cut off, so that it returns to the cut-off state. At this time, the branch and the load arm are kept off, and the start branch is turned on, returning to the initial state. The capacitor C1 is charged in a very short time, and the power supply no longer outputs power to the load.

[0048] In order to further improve the stability of the circuit, the contact switch is connected in parallel with a capacitor C2, whose main function is to resist jitter and prevent the switch state from being triggered by mistake.

[0049] like Figure 2 As shown, the second embodiment of the present invention is based on the first embodiment and newly adds functions such as preventing excessive current and automatic shutdown due to low power, so as to further improve the performance and avoid abnormal conditions of excessive current. At the same time, when the voltage is too low, it automatically identifies and shuts down the circuit.

[0050] Among them, the first protection circuit is connected in parallel at both ends of the resistor R5; the first protection circuit includes: resistor R4, resistor R6, NPN transistor Q5 and NPN transistor Q6; the collector of the NPN transistor Q5 is connected to the collector of the switch tube Q3, the base is connected to the collector of the NPN transistor Q6, and the emitter is connected to the base of the NPN transistor Q6; the emitter of the NPN transistor Q6 is connected to the contact switch; the resistor R4 is connected in parallel with the collector and base of the NPN transistor Q5; the resistor R6 is connected in parallel with the base and emitter of the NPN transistor Q6;

[0051] A second protection circuit is connected in parallel at both ends of the resistor R10; the second protection circuit includes: a resistor R12, a resistor R14, an NPN transistor Q7 and an NPN transistor Q8; the collector of the NPN transistor Q7 is connected between the resistor R9 and the resistor R15 via the resistor R14, the base and the collector of the NPN transistor Q8 are connected between the resistor R9 and the resistor R15, and the emitter is connected to the base of the NPN transistor Q8; the emitter of the NPN transistor Q8 is connected to the collector of the switch tube Q2; the resistor R12 is connected in parallel with the base and emitter of the NPN transistor Q8;

[0052] A third protection circuit is arranged between the switch tube Q2 and the ground; the third protection circuit comprises: an NPN transistor Q11 and a resistor R11; the collector and base of the NPN transistor Q11 are respectively connected to the base and emitter of the switch tube Q2, and the emitter is grounded; one end of the resistor R11 is connected to the emitter of the switch tube Q2, and the other end is grounded.

[0053] A low voltage shutdown circuit is connected in parallel at both ends of the resistor R16; the low voltage shutdown circuit includes: resistor R18, resistor R19, resistor R20, resistor R21, resistor R22, NPN transistor Q9, NPN transistor Q10 and temperature drift compensation diode D1; the collector and base of the NPN transistor Q9 are connected to the collector of the switch tube Q4 through resistor R21 and resistor R22 respectively, and the emitter is grounded through resistor R19; the emitter of the NPN transistor Q10 is grounded, the base is connected to the collector of the NPN transistor Q9, and the collector is connected to the end of the contact switch away from the capacitor C1; the temperature drift compensation diode D1 is connected to the base of the NPN transistor Q9, and is connected in series with the resistor R18 and the resistor R20 and then grounded.

[0054] When the power supply voltage is lower than the set threshold, the low voltage shutdown circuit can automatically turn off the switch tube of the feedback control bridge.

[0055] This patent is not limited to the above-mentioned best implementation mode. Anyone can derive other forms of constant current zero-power bistable circuits and control methods under the inspiration of this patent. All equal changes and modifications made according to the scope of the patent application of the present invention should be covered by this patent.

Claims

1. A constant current zero power consumption bistable circuit, characterized in that: include: A control arm, a load arm and a feedback control bridge between the two arms are arranged between the power supply and the ground; The control arm includes a starting branch, a holding branch and a discharging branch; The start-up branch is used to charge the capacitor C1; the holding branch, the discharge branch, the feedback control bridge and the load arm all include a switch tube; The capacitor C1 is used as a control switch of the switch tube Q2 of the feedback control bridge through the contact switch; the switch tube Q2 of the feedback control bridge is used as a control switch of the switch tube Q3 of the holding branch and the switch tube Q4 of the load arm; the switch tube Q3 of the holding branch is used as a control switch of the switch tube Q1 of the discharge branch; the discharge branch is used to discharge the capacitor C1; the switch tube Q2 and the switch tube Q3 form a self-locking structure; The start-up branch includes a resistor R1, a resistor R2 and a capacitor C1 connected in series, the resistor R1 is connected to a power supply; one end of the capacitor C1 is grounded, and the other end is connected to one end of a contact switch; The holding branch includes a switch tube Q3, a resistor R5 and a resistor R8 connected to each other; the switch tube Q3 is a PNP type triode, the emitter is connected to the power supply, and the collector is connected to the resistor R5; the resistor R8 is grounded; the other end of the contact switch is connected between the resistor R5 and the resistor R8; The discharge branch includes a switch tube Q1 and a resistor R3; the switch tube Q1 is an NPN type triode, the base is connected to the collector of the switch tube Q3 via the resistor R3, the collector is connected between the resistor R1 and the resistor R2, and the emitter is grounded; The switch tube Q4 used in the load arm is a PNP type triode, the emitter of which is connected to the power supply, and the collector is grounded through a resistor R16 and serves as a port for connecting the load; The feedback control bridge comprises a resistor R15, a resistor R10 and a switch tube Q2 connected in series, the resistor R15 is connected to a power supply; the switch tube Q2 is an NPN type triode, the emitter is grounded, the collector is connected to the resistor R10, and the base is connected between the resistor R5 and the resistor R8 through the resistor R7; the other end of the resistor R10 is connected to the base of the switch tube Q3 and the switch tube Q4 through the resistor R9 and the resistor R13 respectively; A low voltage shutdown circuit is connected in parallel at both ends of the resistor R16; the low voltage shutdown circuit includes: resistor R18, resistor R19, resistor R20, resistor R21, resistor R22, NPN transistor Q9, NPN transistor Q10 and temperature drift compensation diode D1; the collector and base of the NPN transistor Q9 are connected to the collector of the switch tube Q4 through resistor R21 and resistor R22 respectively, and the emitter is grounded through resistor R19; the emitter of the NPN transistor Q10 is grounded, the base is connected to the collector of the NPN transistor Q9, and the collector is connected to the end of the contact switch away from the capacitor C1; the cathode of the temperature drift compensation diode D1 is connected to the base of the NPN transistor Q9, and the anode is connected in series with the resistor R18 and the resistor R20 and then grounded.

2. The constant current zero power consumption bistable circuit according to claim 1, characterized in that: The contact switch is connected in parallel with a capacitor C2.

3. The constant current zero power consumption bistable circuit according to claim 1, characterized in that: The two ends of the resistor R5 are connected in parallel with a first protection circuit; the first protection circuit includes: a resistor R4, a resistor R6, an NPN transistor Q5 and an NPN transistor Q6; the collector of the NPN transistor Q5 is connected to the collector of the switch tube Q3, the base is connected to the collector of the NPN transistor Q6, and the emitter is connected to the base of the NPN transistor Q6; the emitter of the NPN transistor Q6 is connected to the contact switch; the resistor R4 is connected in parallel with the collector and base of the NPN transistor Q5; the resistor R6 is connected in parallel with the base and emitter of the NPN transistor Q6; A second protection circuit is connected in parallel at both ends of the resistor R10; the second protection circuit includes: a resistor R12, a resistor R14, an NPN transistor Q7 and an NPN transistor Q8; the collector of the NPN transistor Q7 is connected between the resistor R9 and the resistor R15 via the resistor R14, the base and the collector of the NPN transistor Q8 are connected between the resistor R9 and the resistor R15, and the emitter is connected to the base of the NPN transistor Q8; the emitter of the NPN transistor Q8 is connected to the collector of the switch tube Q2; the resistor R12 is connected in parallel with the base and emitter of the NPN transistor Q8; A third protection circuit is arranged between the switch tube Q2 and the ground; the third protection circuit comprises: an NPN transistor Q11 and a resistor R11; the collector and base of the NPN transistor Q11 are respectively connected to the base and emitter of the switch tube Q2, and the emitter is grounded; one end of the resistor R11 is connected to the emitter of the switch tube Q2, and the other end is grounded.

4. The control method of the constant current zero power consumption bistable circuit according to claims 1-3, characterized in that: In the initial state of connecting to the power supply, only the start-up branch is turned on, the bases of the switch tubes of the load arm, the feedback control bridge, the holding branch and the discharge branch are all at 0 potential, and the capacitor C1 is charged to a saturated state; The contact switch is then used to switch between the following two states: State 1: The switch tubes of the feedback control bridge and the discharge branch are turned on by the potential difference provided by the capacitor C1, so that the holding branch and the load arm are turned on; the capacitor C1 is discharged by the discharge branch; State 2: The switch tube of the feedback control bridge is controlled by the capacitor C1 to be powered off and return to the cut-off state, so that the holding branch, the load arm and the discharge branch are turned off, and the starting branch is turned on.

5. The control method of the constant current zero power consumption bistable circuit according to claim 4, characterized in that: When the power supply voltage is lower than a set threshold, the low voltage shutdown circuit turns off the switch tube of the feedback control bridge.

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