阅读说明：本技术 一种继电器防粘连及保护驱动管脚控制电路及装置 (Relay anti-adhesion and drive pin protection control circuit and device ) 是由 马钊 赖吉健 赵运德 陈卓 于 2020-05-28 设计创作，主要内容包括：本发明提供一种继电器防粘连及保护驱动管脚控制电路。包括至少包括钳位二极管、耗散电阻、功率MOS以及用于防止感应电压击穿功率MOS的第一二极管,其中：所述钳位二极管的负极连接所述功率MOS的漏极,所述功率MOS的栅极连接单片机控制输出端,所述耗散电阻的一端连接所述功率MOS的源极,所述耗散电阻的另一端连接所述第一二极管的负极,所述第一二极管的正极连接所述钳位二极管的正极。本发明由电阻和二极管组成,成本非常低,能有效避免继电器关断过程粘连,能有效保护驱动管口不受感生电压损坏。(The invention provides a control circuit for preventing a relay from adhering and protecting a driving pin. Including at least including clamping diode, dissipation resistance, power MOS and be used for preventing the induction voltage from breaking down the first diode of power MOS, wherein: the negative electrode of the clamping diode is connected with the drain electrode of the power MOS, the grid electrode of the power MOS is connected with the control output end of the single chip microcomputer, one end of the dissipation resistor is connected with the source electrode of the power MOS, the other end of the dissipation resistor is connected with the negative electrode of the first diode, and the positive electrode of the first diode is connected with the positive electrode of the clamping diode. The invention is composed of a resistor and a diode, has very low cost, can effectively avoid the adhesion in the turn-off process of the relay, and can effectively protect the driving pipe orifice from being damaged by induced voltage.)

1. The utility model provides an antiseized even and protection drive pin control circuit of relay, its characterized in that includes at least that the clamper diode, dissipation resistance, power MOS and be used for preventing the first diode of induced voltage breakdown power MOS, wherein:

the negative electrode of the clamping diode is connected with the drain electrode of the power MOS, the grid electrode of the power MOS is connected with the control output end of the single chip microcomputer, one end of the dissipation resistor is connected with the source electrode of the power MOS, the other end of the dissipation resistor is connected with the negative electrode of the first diode, and the positive electrode of the first diode is connected with the positive electrode of the clamping diode.

2. The circuit of claim 1, wherein the clamping diode comprises a plurality of diodes connected in series, a clamping voltage V of a single one of the clamping diodes_zThe following formula is satisfied:

V_z＝1.5V_r

wherein, V_rThe rated voltage is used for the operation of the relay.

3. The circuit according to claim 2, further comprising relay driving coils, one ends of which are connected between the cathodes of the clamping diodes and the drains of the power MOS, respectively, and the other ends of which are connected to a power supply terminal.

4. The circuit of claim 3, wherein when the relay is turned off, the power MOS is turned off, and an induced voltage V generated by the relay driving coil is generated_inductionSequentially flows through the clamping diode, the first diode and the dissipation resistor.

5. As in claimThe circuit of claim 4, wherein the voltage V is applied across the dissipation resistor₁Greater than the threshold voltage V of the power MOS_gWhen the power MOS is connected, the induced voltage V_inductionSequentially flows through the clamping diode, the first diode, the dissipation resistor and the power MOS.

6. The circuit of claim 1, wherein the source of the power MOS and the dissipation resistor are each connected to ground.

7. A device for preventing adhesion of a relay and protecting control of a driving pin, which comprises the circuit as claimed in any one of claims 1 to 6.

Technical Field

The invention relates to the field of new energy automobile safety, in particular to a control circuit and a control device for preventing a relay from adhering and protecting a driving pin.

Background

At present, a freewheeling diode is added in a coil driving circuit for controlling a relay in the field, so that the conduction of an inverse peak voltage along a power line can be prevented, but because a suppression element and a driving coil form a loop, current continuously flows in the loop, and because the current in the driving coil is influenced by Lenz's law, the current always exists and cannot disappear in an ideal state; in the real state, the current decays slowly. Therefore, the suppression element is introduced, so that the current reduction speed in the coil is reduced slowly (namely, the attraction force for attracting the armature is only reduced slowly and is not suddenly reduced), and the contact opening time side length is long. The life of the relay is impaired.

As shown in fig. 1, there are four main prior art schemes, a: at the moment of S disconnection, a loop in which the resistor R1 is located provides a release channel for energy stored in the relay coil, so that the attenuation of current can be accelerated, but induced voltage in the coil cannot be inhibited; scheme B: the diode D1 provides a low-resistance path in the positive direction of the induced voltage to inhibit the induced voltage, but the loop current is slowly attenuated due to low circuit impedance, which is not beneficial to avoiding the adhesion of the relay; scheme C: realizing follow current and inhibiting induced potential through TVS; scheme D: voltage stabilization and current freewheeling are realized through a diode Z1; the diode is only used as the B/C/D proposal, and only can continue current and can not consume energy; scheme A, only can accelerate attenuation and cannot inhibit induced voltage

Disclosure of Invention

The technical problem to be solved by the embodiment of the invention is to provide a control circuit and a device for preventing the adhesion of a relay and protecting a driving pin, which can accelerate the consumption speed of energy induced in a coil of the relay, thereby accelerating the turn-off time of the relay; the technical problem of protecting the driving nozzle from the influence of the induced voltage of the kilovolt level.

In one aspect of the present invention, a control circuit for preventing adhesion of a relay and protecting a driving pin is provided, which includes:

at least comprises a clamping diode, a dissipation resistor, a power MOS and a first diode for preventing the induced voltage from breaking down the power MOS, wherein:

the negative electrode of the clamping diode is connected with the drain electrode of the power MOS, the grid electrode of the power MOS is connected with the control output end of the single chip microcomputer, one end of the dissipation resistor is connected with the source electrode of the power MOS, the other end of the dissipation resistor is connected with the negative electrode of the first diode, and the positive electrode of the first diode is connected with the positive electrode of the clamping diode.

Further, the clamping diode comprises a plurality of diodes connected in series, and the clamping voltage V of a single diode in the clamping diode_zThe following formula is satisfied:

V_z＝1.5V_r

wherein, V_rThe rated voltage is used for the operation of the relay.

The power supply circuit further comprises a relay driving coil, one end of the relay driving coil is respectively connected between the cathode of the clamping diode and the drain electrode of the power MOS, and the other end of the relay driving coil is connected with a power supply end.

Further, when the relay is turned off, the power MOS is turned off, and an induced voltage V generated by the relay driving coil_inductionSequentially flows through the clamping diode, the first diode and the dissipation resistor.

Further, when the voltage V is applied across the dissipation resistor₁Greater than the threshold voltage V of the power MOS_gWhen the power MOS is connected, the induced voltage V_inductionSequentially flows through the clamping diode, the first diode, the dissipation resistor and the power MOS.

Further, the source of the power MOS and the dissipation resistor are respectively connected to a ground terminal.

Correspondingly, the invention also provides a control device for preventing the adhesion of the relay and protecting the driving pin, which comprises the following circuit,

at least comprises a clamping diode, a dissipation resistor, a power MOS and a first diode for preventing the induced voltage from breaking down the power MOS, wherein:

the negative electrode of the clamping diode is connected with the drain electrode of the power MOS, the grid electrode of the power MOS is connected with the control output end of the single chip microcomputer, one end of the dissipation resistor is connected with the source electrode of the power MOS, the other end of the dissipation resistor is connected with the negative electrode of the first diode, and the positive electrode of the first diode is connected with the positive electrode of the clamping diode.

In summary, the embodiment of the invention has the following beneficial effects:

the control circuit and the device for preventing the adhesion of the relay and protecting the driving pin only consist of the resistor and the diode, so the cost is very low; guarantee to have the afterflow return circuit in the twinkling of an eye at relay disconnection, the protection drives the mouth and does not receive the influence of coil energy induced voltage in the relay, and coil energy obtains effective consumption simultaneously, avoids the break-off time overlength to lead to the relay adhesion.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is within the scope of the present invention for those skilled in the art to obtain other drawings based on the drawings without inventive exercise.

FIG. 1 is a schematic diagram of a prior art keeper control circuit;

FIG. 2 is a schematic diagram of a control circuit for preventing adhesion of a relay and protecting a driving pin according to the present invention;

fig. 3 is a working schematic diagram of the relay anti-adhesion and driving pin protection control circuit provided by the invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings.

The anti-adhesion and driving pin protection circuit for the relay provides a method for accurately and comprehensively calculating and expressing the efficiency of the circuit.

As shown in fig. 2 and fig. 3, a main flow diagram of an embodiment of a relay adhesion prevention and driving pin protection control circuit provided by the present invention is shown. In this embodiment, the circuit includes:

the power supply comprises a clamping diode D2, a dissipation resistor R6, a power MOS and a first diode D3 for preventing induced voltage from breaking down the power MOS, wherein the cathode of the clamping diode D2 is connected with the drain of the power MOS, the gate of the power MOS is connected with a singlechip control output end Ctrl, one end of the dissipation resistor R6 is connected with the source of the power MOS, the other end of the dissipation resistor D6 is connected with the cathode of a first diode D3, and the anode of the first diode D3 is connected with the anode of the clamping diode D2; the circuit is used in a relay driving interface of a battery management system of a power battery of an electric automobile and consists of an MOSFET, a resistor and a diode. The circuit can ensure that a follow current loop is instantly formed when the relay is disconnected, the driving port is protected from the influence of coil energy induced voltage in the relay, meanwhile, the coil energy is effectively consumed, and relay adhesion caused by overlong disconnection time is avoided.

Specifically, according to the actual relay parameter configuration, if the stored energy in the relay coil is too high, the formed induced voltage has the possibility of breaking down the MOS, so that the addition of D3 can effectively prevent the risk.

Specifically, in one embodiment, the clamping diode D2 includes a plurality of diodes connected in series, and the specific number of the diodes connected in series depends on the clamping voltage V of a single diode_zRated voltage V for relay operation_rA clamping voltage V of a single diode in the clamping diode D2_zThe following formula is satisfied:

V_z＝1.5V_r

wherein, V_rThe rated voltage is used for the operation of the relay.

In a specific embodiment, the power supply device further comprises a Relay driving coil Relay, one end of each Relay driving coil Relay is respectively connected between the negative electrode of the clamping diode D2 and the drain of the power MOS, and the other end of each Relay driving coil Relay is connected with a power supply terminal PWR.

Specifically, when the Relay is turned off, the power MOS is turned off, and the induced voltage V generated by the Relay drive coil Relay is generated_inductionFlows through the clamping diode D2, the first diode D3 and the dissipation resistor D6 in sequence.

Specifically, when the Relay is turned off, the power MOS is turned off, and the induced voltage V generated by the Relay drive coil Relay is generated_inductionSequentially flows through the clamping diode D2, the first diode D3 and the dissipation resistor D6; when the voltage V is applied across the dissipation resistor D6₁Greater than the threshold voltage V of the power MOS_gWhen the power MOS is connected, the induced voltage V_inductionFlows through the clamping diode D2, the first diode D3, the dissipation resistor D6 and the power MOS in sequence.

In a specific embodiment, the source of the power MOS and the dissipation resistor are respectively connected to a ground terminal.

In another embodiment of the present invention, the circuit includes a clamping diode D2, a dissipation resistor R6, and a power MOS, wherein a negative electrode of the clamping diode D2 is connected to a drain of the power MOS, a gate of the power MOS is connected to a single-chip microcomputer control output Ctrl, one end of the dissipation resistor R6 is connected to a source of the power MOS, and the other end of the dissipation resistor D6 is connected to a positive electrode of the clamping diode D2; the circuit is used in a relay driving interface of a battery management system of a power battery of an electric automobile and consists of an MOSFET, a resistor and a diode. The circuit can ensure that a follow current loop is instantly formed when the relay is disconnected, the driving port is protected from the influence of coil energy induced voltage in the relay, meanwhile, the coil energy is effectively consumed, and relay adhesion caused by overlong disconnection time is avoided.

Correspondingly, the invention further provides a relay adhesion prevention and drive pin protection control device, which comprises a circuit including a clamping diode D2, a dissipation resistor R6, a power MOS and a first diode D3 for preventing an induced voltage from breaking down the power MOS, wherein a cathode of the clamping diode D2 is connected to a drain of the power MOS, a gate of the power MOS is connected to a control output Ctrl of a single-chip microcomputer, one end of the dissipation resistor R6 is connected to a source of the power MOS, the other end of the dissipation resistor D6 is connected to a cathode of the first diode D3, and an anode of the first diode D3 is connected to an anode of the clamping diode D2.

As shown in FIG. 3, the present invention providesThe Relay anti-adhesion and driving pin protection circuit comprises a power MOS (metal oxide semiconductor), a Relay driving coil Relay, a clamping diode D2, a dissipation resistor R6, a first diode D3, a resistor D2, a resistor D6, a resistor D and a resistor D3. At the moment when the relay is switched from a closed state to an open state, the level of an output Ctrl end controlled by the single chip microcomputer is pulled down from high, and the voltage V at two ends of a dissipation resistor R6_rPulling down, switching off the power MOS tube, and generating induced voltage V in the Relay drive coil Relay due to the stored energy_inductionAt this time, since the power MOS is already turned off, the induced voltage V_inductionThe current through the clamping diode D2/the first diode D3/the dissipation resistor R6, and the current I flowing through the dissipation resistor R6, which results in the voltage V across the dissipation resistor R6_rAnd rises when V_rGreater than threshold voltage V of power MOS_gWhen the power MOS is turned back on, V_inductionThe first path through the clamp diode D2/first diode D3/dissipation resistor R6 becomes parallel to the power MOS switch through the clamp diode D2/first diode D3/dissipation resistor R6, and since the power MOS switch has a smaller impedance, the coil energy is quickly drained for the main drain loop. When the energy is discharged to a certain degree, V_inductionIs not sufficient to continue breaking down the clamping diode D2, so I is zero, V_rWhen the voltage approaches 0V, the power MOS is cut off again, the current of the coil is 0A, and the relay is completely turned off.

In summary, the embodiment of the invention has the following beneficial effects:

the anti-adhesion and driving pin protection circuit for the relay only consists of the resistor and the diode, so that the cost is very low; a follow current loop is ensured at the moment of disconnection of the relay, the driving port is protected from the influence of the energy induced voltage of the coil in the relay, meanwhile, the energy of the coil is effectively consumed, and the relay adhesion caused by overlong disconnection time is avoided; the relay coil energy is supported to be quickly released, the relay is supported to be quickly turned off, and the relay coil energy can work cooperatively to exert the optimal effect; the driving pipe orifice can be effectively protected from being damaged by induced voltage.

While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.