Remote PMOS (P-channel Metal Oxide Semiconductor) driving circuit suitable for change-over switch electric appliance

Abstract

The utility model discloses a remote PMOS (P-channel Metal Oxide Semiconductor) drive circuit suitable for transfer switching equipment, which comprises a shunt resistor connected in series with a protection transient voltage suppressor diode which is grounded; the divider resistor mechanism comprises a first divider resistor and a second divider resistor which are connected in series with the shunt resistor; the filter capacitor is connected with the first divider resistor in parallel and connected with the second divider resistor in series, a Zener diode is connected in series in a series circuit of the shunt resistor and the second divider resistor, and the filter capacitor is connected with an electrostatic protection diode in parallel. The utility model relates to a drive circuit suitable for remote control, and aims to solve the problems that in the existing application of a dual-power change-over switch, remote control is generally needed, a connecting cable is relatively long, electromagnetic interference is relatively easy to couple, a commonly used PMOS drive circuit only depends on simple resistor voltage division, the anti-interference capability is weak, and the use requirement cannot be met, so that a drive circuit suitable for remote control is designed.

Description

Technical Field

[0001] The utility model relates to the technical field of switch electrical appliance circuits, in particular to a remote PMOS drive circuit suitable for switching electrical appliances. Background Art

[0002] A dual power switch is a switch that automatically switches to another power source due to a power outage. It is an integrated circuit with P-channel MOS field effect transistor as the basic component, referred to as PMOS. The working condition of PMOS is to apply a negative voltage on the gate relative to the source, that is, negatively charged electrons are applied to the gate of PMOS, and what are induced in the substrate are movable positively charged holes and a depletion layer with fixed positive charge. Without considering the influence of the charge in silicon dioxide, the number of positive charges induced in the substrate is equal to the number of negative charges on the PMOS gate.

[0003] However, it still has the following disadvantages in actual use:

[0004] In the current dual power conversion switch application, there is usually a need for remote control. The connecting cable is long and is more likely to couple electromagnetic interference. The commonly used PMOS drive circuit only relies on simple resistor voltage division and has weak anti-interference ability and cannot meet the use requirements. Therefore, a drive circuit suitable for remote control is designed. Utility Model Content

[0005] Technical solutions to be solved

[0006] The purpose of the utility model is to provide a remote PMOS drive circuit suitable for a switching appliance, so as to solve the problem raised in the above-mentioned background technology that in the existing dual power conversion switch application, there is usually a need for remote control, the connection cable is long, and it is easier to couple electromagnetic interference, while the commonly used PMOS drive circuit only relies on simple resistance voltage division, has weak anti-interference ability, and cannot meet the use requirements. For this reason, a drive circuit suitable for remote control is designed.

[0007] Technical Solution

[0008] In order to solve the above technical problems, the utility model is achieved through the following technical solutions:

[0009] The utility model is a remote PMOS drive circuit suitable for a switching device, comprising:

[0010] A shunt resistor, wherein the shunt resistor is connected in series with a protective transient voltage suppression diode, and the protective transient voltage suppression diode is grounded;

[0011] A voltage-dividing resistor mechanism comprises a first voltage-dividing resistor and a second voltage-dividing resistor connected in series with the shunt resistor;

[0012] The filter capacitor is connected in parallel with the first voltage-dividing resistor and in series with the second voltage-dividing resistor.

[0013] Furthermore, a Zener diode is connected in series with the shunt resistor and the second voltage-dividing resistor in the series circuit;

[0014] Specifically, the circuit is voltage-divided by a Zener diode, the current threshold of the driving signal is configured by a voltage-dividing resistor, and the circuit is protected by a transient voltage suppression diode.

[0015] Furthermore, it also includes an electrostatic protection diode, the filter capacitor is connected in parallel with the electrostatic protection diode, and the electrostatic protection diode is connected in series with the second voltage-dividing resistor;

[0016] Specifically, the AC component is filtered out by the filter capacitor, making the output DC smoother.

[0017] Furthermore, it also includes an output transistor, which is connected in series with the shunt resistor and in parallel with the first voltage-dividing resistor;

[0018] Specifically, the current is controlled by the output transistor.

[0019] Furthermore, it also includes a pull-down resistor connected in series with the output transistor, and the pull-down resistor is grounded;

[0020] Specifically, the pull-down resistor is grounded to protect the circuit.

[0021] Furthermore, it also includes a remote control signal and an output signal, wherein the remote control signal is connected in series with the shunt resistor, and the output signal is connected in series with the output transistor;

[0022] Specifically, the remote control signal voltage V SignalInput When the remote control signal voltage V SignalInput When it is low enough, Signal Output outputs VCC high level, and Signal Input will flow through the set current.

[0023] Beneficial Effects

[0024] Compared with the prior art, the advantages of the present invention are:

[0025] 1. In the present invention, electromagnetic interference is usually a single or grouped voltage pulse, with a high equivalent internal resistance and weak current driving capability. By setting appropriate voltage and current thresholds, the expected electromagnetic interference will not meet these two requirements at the same time, so that the interference will not cause the PMOS tube to turn on, effectively improving stability.

[0026] 2. Based on the first beneficial effect, R1 will carry current and may generate heat. Therefore, different components are used to set the voltage and current thresholds. The advantage of this is that when laying out the components, the heating situation can be comprehensively considered, and the heating points can be kept away from the voltage sensitive points to reduce the voltage drift caused by temperature. At the same time, it can also facilitate the design of the heat dissipation system.

[0027] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for describing the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0029] Figure 1 This is a driving circuit of the utility model.

[0030] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0031] 1. Shunt resistor; 2. Voltage divider resistor mechanism; 201. First voltage divider resistor; 202. Second voltage divider resistor; 3. Filter capacitor; 4. Electrostatic protection diode; 5. Zener diode; 6. Transient voltage suppression diode; 7. Output transistor; 8. Pull-down resistor; 9. Remote control signal; 10. Output signal. DETAILED DESCRIPTION

[0032] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below with reference to the accompanying drawings.

[0033] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific implementation methods disclosed below.

[0034] In order to make the purpose, technical solution and advantages of the present invention more clear, the implementation mode of the present invention will be further described in detail below with reference to the accompanying drawings.

[0035] Embodiment 1

[0036] See also Figure 1 As shown, this embodiment is a remote PMOS drive circuit suitable for a switching device, comprising:

[0037] A shunt resistor 1, the shunt resistor 1 is connected in series with a transient voltage suppression diode 6, and the transient voltage suppression diode 6 is grounded;

[0038] The voltage-dividing resistor mechanism 2 comprises a first voltage-dividing resistor 201 and a second voltage-dividing resistor 202 connected in series with the shunt resistor 1;

[0039] The filter capacitor 3 is connected in parallel with the first voltage-dividing resistor 201 and in series with the second voltage-dividing resistor 202;

[0040] The shunt resistor 1 and the second voltage dividing resistor 202 are connected in series with a Zener diode 5;

[0041] The electrostatic protection diode 4 is connected in parallel with the filter capacitor 3, and the electrostatic protection diode 4 is connected in series with the second voltage-dividing resistor 202;

[0042] An output transistor 7 is connected in series with the shunt resistor 1 and in parallel with the first voltage dividing resistor 201;

[0043] A pull-down resistor 8 is connected in series with the output transistor 7 and is grounded;

[0044] A remote control signal 9 and an output signal 10, wherein the remote control signal 9 is connected in series with the shunt resistor 1, and the output signal 10 is connected in series with the output transistor 7;

[0045] To improve stability, the following steps are announced;

[0046] Remote control signal voltage V SignalInput When the remote control signal voltage V SignalInput When it is low enough, Signal Output outputs VCC high level. At this time, Signal Input will flow through the set current;

[0047] To turn on PMOS1, its gate-source voltage V G-S =V G -VCC should be less than the PMOS start-up threshold voltage V 阈值 , where V G =VCC-R2*(VCC-V SignalInput -V ZENER1 ) / (R2+R3), when turned on, the gate-source voltage must meet: V G-S =V G -VCC=VCC-R2*(VCC-V SignalInput -V ZENER1 ) / (R2+R3)-VCC <V 阈值 , from which we can get: V SignalInput <VCC+V 阈值*(R2+R3) / R2-V ZENER1 = Turn-on voltage threshold. According to the above inequality, PMOS will only have output when the control signal voltage is less than the set turn-on voltage threshold. ZENER1 , you can adjust the turn-on voltage threshold. A voltage regulator is used here to improve the accuracy of the voltage threshold.

[0048] After determining the required turn-on voltage threshold, the corresponding current value is: turn-on current threshold = (VCC-turn-on voltage threshold) / R1; PMOS will only be turned on when the current that the remote control signal can carry is greater than the turn-on current threshold. Otherwise, due to the low current value, according to Ohm's law, the voltage drop on R1 (V R1 ) will decrease, V SignalInput =VCC – V R1 ,V SignalInput It will increase, and the voltage threshold condition will not be met, and the PMOS will not be turned on. By setting the value of R1, the current threshold can be adjusted;

[0049] Usually electromagnetic interference is a single or group voltage pulse, with high equivalent internal resistance and weak current driving capability. By setting appropriate voltage and current thresholds, the expected electromagnetic interference will not meet these two requirements at the same time, so that the interference will not cause the PMOS tube to turn on;

[0050] R1 will carry current and may generate heat. Therefore, different components are used to set the voltage and current thresholds. The advantage of this is that the heating situation can be taken into account when laying out the components.

[0051] This step effectively improves stability, keeps heat points away from voltage sensitive points, reduces voltage drift caused by temperature, and also facilitates the design of the heat dissipation system.

[0052] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0053] Finally, it should be noted that the above description is only a preferred embodiment of the utility model and is not intended to limit the utility model. Although the utility model is described in detail with reference to the above embodiments, those skilled in the art can still modify the technical solutions recorded in the above embodiments or replace some of the technical features therein with equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A remote PMOS drive circuit suitable for a switching device, characterized in that: include: A shunt resistor (1), the shunt resistor (1) being connected in series with a protective transient voltage suppression diode (6), the protective transient voltage suppression diode (6) being grounded; A voltage-dividing resistor mechanism (2), comprising a first voltage-dividing resistor (201) and a second voltage-dividing resistor (202) connected in series with the shunt resistor (1); The filter capacitor (3) is connected in parallel with the first voltage-dividing resistor (201) and in series with the second voltage-dividing resistor (202).

2. A remote PMOS drive circuit suitable for a switching device according to claim 1, characterized in that The shunt resistor (1) and the second voltage-dividing resistor (202) are connected in series with a Zener diode (5).

3. A remote PMOS drive circuit suitable for a switching device according to claim 1, characterized in that: It also includes an electrostatic protection diode (4), the filter capacitor (3) is connected in parallel with the electrostatic protection diode (4), and the electrostatic protection diode (4) is connected in series with the second voltage-dividing resistor (202).

4. A remote PMOS drive circuit suitable for a switching device according to claim 1, characterized in that: It also includes an output transistor (7), which is connected in series with the shunt resistor (1) and in parallel with the first voltage dividing resistor (201).

5. A remote PMOS drive circuit suitable for a switching device according to claim 4, characterized in that: It also includes a pull-down resistor (8) connected in series with the output transistor (7), and the pull-down resistor (8) is grounded.

6. A remote PMOS drive circuit suitable for a switching device according to claim 4, characterized in that: It also includes a remote control signal (9) and an output signal (10), wherein the remote control signal (9) is connected in series with the shunt resistor (1), and the output signal (10) is connected in series with the output transistor (7).

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