CN210225370U - MOS opens circuit - Google Patents

Abstract

A MOS opens the circuit, including electric capacity, diode and MOS tube; one end of the first capacitor is connected with an IO port of the singlechip, and the other end of the first capacitor is connected with the anode of the diode; one end of the second capacitor is connected with the cathode of the diode, and the other end of the second capacitor is grounded; the source electrode and the drain electrode of the first MOS tube are respectively connected with the power input end and the power output end, and the grid electrode of the first MOS tube is connected with the drain electrode of the second MOS tube; the grid electrode of the second MOS tube is connected with the cathode of the diode, and the source electrode of the second MOS tube is grounded. The MOS starting circuit can charge and discharge a capacitor when the single chip microcomputer works normally, keeps the conduction of an MOS tube, ensures the connection between the input and the output of a power supply, and enables equipment to work normally in a power supply mode. And when software in the single chip microcomputer runs and bug occurs and high level is continuously output, the first capacitor is opened in the charging ending stroke, the second capacitor is further enabled to end discharging to turn off the second MOS tube, finally the first MOS tube is turned off, connection between power supply input and output is cut off, power supply is stopped, and overheating burnout caused by long-time electrification is avoided.

Description

MOS opens circuit

Technical Field

The utility model belongs to switch protection circuit field especially relates to a MOS opens circuit.

Background

In the existing equipment, a single chip microcomputer is directly adopted to control the MOS, so that the input and the output of the MOS control equipment are conducted. However, when the software in the single chip microcomputer runs and bug occurs, the signal output of the single chip microcomputer is continuously high level, so that the MOS is in a continuous conduction state, the input and the output of the equipment are continuously conducted, the running part in the equipment is continuously in an open state, and the running part generates heat and continuously heats up, even has the risk of burning out.

SUMMERY OF THE UTILITY MODEL

The utility model discloses there is the MOS to the switch circuit of current singlechip direct control MOS and continuously switches on the problem that causes to generate heat or burn out, provides a MOS and opens the circuit.

In order to achieve the above object, the utility model discloses a technical scheme be:

a MOS opens the circuit, including electric capacity, diode and MOS tube;

the capacitor comprises a first capacitor and a second capacitor;

one end of the first capacitor is connected with an IO port of the singlechip, and the other end of the first capacitor is connected with the anode of the diode;

one end of the second capacitor is connected with the cathode of the diode, and the other end of the second capacitor is grounded;

the MOS tube comprises a first MOS tube and a second MOS tube;

the source electrode and the drain electrode of the first MOS tube are respectively connected with the power input end and the power output end, and the grid electrode of the first MOS tube is connected with the drain electrode of the second MOS tube;

and the grid electrode of the second MOS tube is connected with the cathode of the diode, and the source electrode of the second MOS tube is grounded.

Preferably, the first MOS transistor is a PMOS.

Compared with the prior art, the utility model discloses an advantage lies in with positive effect:

1. the MOS starting circuit can charge and discharge a capacitor when the single chip microcomputer works normally, keeps the conduction of an MOS tube, ensures the connection between the input and the output of a power supply, and enables equipment to work normally in a power supply mode. And when the software in the singlechip runs and bug occurs and continuously outputs high level, the first capacitor is charged to finish the stroke and is opened, so that the second capacitor finishes discharging to cut off the second MOS tube, finally the first MOS tube is cut off, the connection between the power input and the power output is cut off, the power supply running of the equipment is stopped, and the problem of overheating or burnout caused by long-time power-on running of the equipment is avoided.

2. The first MOS tube for controlling the connection between the input and the output of the power supply adopts a PMOS, the absolute value of the threshold voltage is higher, and the requirement of higher working voltage can be met.

Drawings

Fig. 1 is a circuit diagram of the MOS open circuit of the present invention;

in the above figures: c50, a first capacitance; c56, a second capacitor; d5, a diode; q1, a first MOS tube; q10, second MOS pipe.

Detailed Description

The present invention is specifically described below by way of exemplary embodiments. It should be understood, however, that elements, structures and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.

In the description of the present invention, it should be noted that the terms "inside", "outside", "upper", "lower", "front", "rear", and the like indicate orientations or positional relationships based on positional relationships shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

As shown in fig. 1, the utility model provides a circuit is opened to MOS, including electric capacity, diode and MOS pipe.

The capacitors include a first capacitor C50 and a second capacitor C56.

One end of the first capacitor C50 is connected with the IO port of the singlechip, and the other end is connected with the anode of the diode D5.

One end of the second capacitor C56 is connected to the negative electrode of D5, and the other end is grounded.

The MOS tube comprises a first MOS tube Q1 and a second MOS tube Q10.

The source and the drain of the first MOS transistor Q1 are respectively connected to the power input terminal and the power output terminal, and the gate of the first MOS transistor Q1 is connected to the drain of the second MOS transistor Q10.

The gate of the second MOS transistor Q10 is connected to the cathode of the diode D5, and the source of the second MOS transistor Q10 is grounded.

When the single chip microcomputer works normally, an IO port of the single chip microcomputer sends a pulse signal to the first capacitor C50. Since the capacitor instantaneous current I ═ C × du/dt, the pulse signal keeps du/dt in a changing state, so that the first capacitor C50 outputs a changing forward current.

After the current output by the first capacitor C50 is rectified by the diode D5, the second capacitor C56 is charged with the current and continuously discharges, the conduction of the second MOS transistor Q10 is maintained, the second MOS transistor Q10 continuously transmits a high level to the gate of the first MOS transistor Q1, a large voltage difference is generated between the gate and the source of the first MOS transistor Q1, so that the first MOS transistor Q1 is turned on, the power input end and the power output end are conducted, and the device is powered on to operate.

When the single chip microcomputer works abnormally, the IO port of the single chip microcomputer continuously sends a high level to the first capacitor C50, and after the first capacitor C50 is charged, the high level cannot be discharged, so that a circuit where the first capacitor C50 is located is equivalent to an open circuit state. After the second capacitor C56 discharges, the current output by the first capacitor C50 cannot be obtained and the second capacitor C56 stops discharging to the second MOS transistor Q10, the second MOS transistor Q10 cannot be conducted, the gate of the first MOS transistor Q1 loses the high level transmitted by the second MOS transistor Q10, the first MOS transistor Q1 is turned off, the power input end and the power output end are disconnected, the equipment is stopped from being electrified, and the equipment is prevented from being operated for a long time and being overheated or burnt out.

When the second MOS transistor Q10 delivers a lower level, it is still possible to make the voltage difference between the gate and the source of the first MOS transistor Q1 reach a threshold value, and turn on the first MOS transistor Q1, which causes the turn-on sensitivity of the first MOS transistor Q1 to be too high, and the power input terminal and the power output terminal are turned on for a long time, and the device is overheated due to long-time power-on.

In order to avoid the above problem, the first MOS transistor that controls the connection between the power input and output is a PMOS transistor, and the absolute value of the threshold voltage is high, so that the first MOS transistor can be turned on only when the level transmitted by the second MOS transistor Q10 is high.

Claims (2)

1. The MOS starting circuit is characterized by comprising a capacitor, a diode and an MOS tube;

the capacitor comprises a first capacitor and a second capacitor;

one end of the first capacitor is connected with an IO port of the singlechip, and the other end of the first capacitor is connected with the anode of the diode;

one end of the second capacitor is connected with the cathode of the diode, and the other end of the second capacitor is grounded;

the MOS tube comprises a first MOS tube and a second MOS tube;

the source electrode and the drain electrode of the first MOS tube are respectively connected with the power input end and the power output end, and the grid electrode of the first MOS tube is connected with the drain electrode of the second MOS tube;

and the grid electrode of the second MOS tube is connected with the cathode of the diode, and the source electrode of the second MOS tube is grounded.

2. The MOS turn-on circuit of claim 1, wherein the first MOS transistor is a PMOS.

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