CN215772911U - Input enable hysteresis protection circuit - Google Patents

Abstract

The utility model provides an input enable hysteresis protection circuit which comprises a first circuit and a second circuit, wherein the first circuit comprises a Metal Oxide Semiconductor (MOS) transistor VT₂₂The second circuit comprises a driving chip U₁₅(ii) a MOS tube VT₂₂Is connected with a driving chip U₁₅And connected with the driving chip U_15‑EN‑RCThe pin is connected; grid electrode connecting resistance R of MOS tube VT22₁₈₁And a capacitor C₁₆₄Then grounding; capacitor C₁₆₄The other end far away from the grounding end is sequentially connected with a voltage stabilizing tube VD₃₈、VD₃₇Resistance R₁₈₂Then connect to VCC₁(ii) a MOS tube VT₂₂Is connected with a resistor R between the drain electrode and the source electrode₁₇₈MOS transistor VT₂₂The drain electrode of the transistor is connected with a resistor I, an MOS tube VT₂₂Is connected to the driving chip U through a resistor connection_15‑VINA pin; voltage stabilizing tube VD₃₆Negative electrode and MOS transistor VT₂₂After the drain electrode of the voltage stabilizing tube VD is connected₃₆The positive electrode of (2) is grounded; MOS tube VT₂₂And then grounded through a second resistor. The required functions can be realized by using common general electronic devices, the cost is low, and the functions can be flexibly set according to requirements.

Description

Input enable hysteresis protection circuit

Technical Field

The utility model belongs to the field of circuits, and particularly relates to an input enable hysteresis protection circuit.

Background

When power is supplied to communication equipment, in order to ensure stable and reliable power supply, a redundant power supply system is generally used, wherein one path adopts a battery power supply standby system, and usually a lead-acid battery is used as a backup power supply, so that an enable (undervoltage and startup) protection circuit is required to be added to a power supply input circuit to prevent the input voltage from being too low, the input current from being too high and the power supply from being damaged; and to prevent the repeated on/off of the main board power supply caused by the difference between the no-load voltage and the pull-load voltage of the battery, an enable (under-voltage and on-time) protection with a hysteresis circuit function needs to be added to control the power supply. A conventional hysteresis operational amplifier circuit is usually used to drive the MOSFET for switching control. However, the scheme has the defects that the power supply range of the chip is relatively narrow, a separate voltage-stabilizing power supply circuit is needed, and in addition, the risk of chip power failure exists when foreign technologies are blocked.

SUMMERY OF THE UTILITY MODEL

In order to overcome the defects in the prior art, the utility model provides the input enable hysteresis protection circuit, the required functions can be realized only by using common general electronic devices, the cost is low, and the functions can be flexibly set according to the requirements.

The utility model provides an input enable hysteresis protection circuit, which comprises a first circuit and a second circuit,

the first circuit comprises a MOS transistor VT₂₂The second circuit comprises a driving chip U₁₅；

The MOS transistor VT₂₂Is connected with a driving chip U₁₅And the driving chip U_15-EN-RCThe pin is connected;

the MOS transistor VT₂₂The grid electrode of the grid electrode is connected with a resistor R in sequence₁₈₁And a capacitor C₁₆₄Then grounding;

the capacitor C₁₆₄Are connected in parallel with a resistor R₁₈₃Said capacitor C₁₆₄The other end far away from the grounding end is sequentially connected with a voltage stabilizing tube VD₃₈、VD₃₇Resistance R₁₈₂Then connect to VCC₁；

The MOS transistor VT₂₂Is connected with a resistor R between the drain electrode and the source electrode₁₇₈Said MOS transistor VT₂₂The drain electrode of the MOS transistor is connected with a first resistor, and the MOS transistor VT₂₂Is connected to the driving chip U through the resistor_15-VINA pin;

the MOS transistor VT₂₂The drain electrode is connected with a voltage stabilizing tube VD₃₆The voltage stabilizing tube VD₃₆And the MOS transistor VT₂₂After the drain electrode of the voltage stabilizing tube VD is connected₃₆The positive electrode of (2) is grounded;

the MOS transistor VT₂₂The source electrode of the MOS transistor is connected with a second resistor, and the MOS transistor VT₂₂Grounding after passing through the second resistor;

the second circuit further comprises a third circuit connected to the driving chip U₁₅U of (1)_15-ENA pin;

the driving chip U₁₅U of (1)_15-VCCPin and U_15-GNDA first capacitor is connected in parallel between the pins.

Preferably, the resistance R₁₈₁Is 10K.

Preferably, the capacitance C₁₆₄Has a capacity value of 2.2 microfarads.

Preferably, the resistance R₁₈₃Is 10K.

Preferably, the resistance R₁₈₂Is 10K.

Preferably, the resistance R₁₇₈The resistance value of (3) is 6.2K.

Preferably, the resistor R comprises 82K₁₁₃And a resistance R of 200K₁₁₂。

Preferably, the second resistor comprises a resistor R of 10K₁₇₉And a resistance R of 51K₁₈₀。

Preferably, the third circuit comprises a diode U₃₀Said diode U₃₀And the driving chip U₁₅U of (1)_15-ENPin connection, the diode U₃₀And the negative electrode of the driving chip U_15-EN-RCPin connection via the driver chip U_15-EN-RCA voltage stabilizing tube VD is connected behind the pin₄₄The voltage stabilizing tube VD₄₄Of the negative electrodeAnd the diode U₃₀Is connected with the negative electrode of the voltage stabilizing tube VD₄₄The anode of the voltage stabilizing tube VD is grounded₄₄Both ends of which are connected in parallel with a capacitor C₁₁₅；

The diode U₃₀Are connected in parallel with a resistor R₁₆₁Said diode U₃₀The positive electrode of the capacitor is connected with a capacitor C₁₅₉Via said capacitor C₁₅₉And then grounded.

Preferably, the capacitor I comprises a capacitor C connected in parallel₁₂₇And a capacitor C₁₂₈。

The utility model has the beneficial effects that:

(1) the utility model controls the input detection on-off voltage to enable the series resistor to realize the voltage difference (hysteresis voltage) of the on-off point by the existence of the power supply voltage of the chip, thereby avoiding the repeated on-off of the mainboard power supply caused by the voltage difference of the battery load and the no-load.

(2) The circuit adopts a power supply enabling scheme consisting of simple peripheral circuits to replace an operational amplifier hysteresis scheme; and the hysteresis voltage can be flexibly set according to requirements.

(3) The input enable hysteresis function is realized by using a combination and collocation mode of a voltage regulator tube, a resistor, a MOSFET and a driving chip; the hysteresis voltage range can be realized by changing the resistance value of the control resistor according to the requirement.

Drawings

FIG. 1 is a circuit diagram of a first circuit of the present invention;

FIG. 2 is a circuit diagram of a second circuit of the present invention.

Detailed Description

In order to facilitate an understanding of the utility model, the utility model will now be described more fully hereinafter with reference to the accompanying drawings, in which several embodiments of the utility model are shown, but which may be embodied in many different forms and are not limited to the embodiments described herein, but rather are provided for the purpose of providing a more thorough disclosure of the utility model.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs; the terminology used herein in the description of the utility model is for the purpose of describing particular embodiments only and is not intended to be limiting of the utility model; as used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

The utility model provides an input enable hysteresis protection circuit, which can realize the required functions only by using common general electronic devices, has low cost and can be flexibly set according to the requirements.

The input enable hysteresis protection circuit provided by the utility model comprises a first circuit and a second circuit, wherein the first circuit is a detection and hysteresis voltage generation circuit, and the second circuit is an enable action execution circuit.

The first circuit comprises a MOS transistor VT₂₂The second circuit comprises a driving chip U₁₅；

MOS tube VT₂₂Is connected with a driving chip U₁₅And is communicated with a U15-EN-RC pin of the driving chip;

MOS tube VT₂₂The grid electrode of the grid electrode is connected with a resistor R in sequence₁₈₁And a capacitor C₁₆₄Then grounding;

capacitor C₁₆₄Are connected in parallel with a resistor R₁₈₃Capacitor C₁₆₄The other end far away from the grounding end is sequentially connected with a voltage stabilizing tube VD₃₈、VD₃₇Resistance R₁₈₂Then connect to VCC₁；

MOS tube VT₂₂Is connected with a resistor R between the drain electrode and the source electrode₁₇₈MOS transistor VT₂₂The drain electrode of the transistor is connected with a resistor I, an MOS tube VT₂₂Is connected to the driving chip U through a resistor connection_15-VINA pin;

MOS tube VT₂₂The drain electrode is connected with a voltage stabilizing tube VD₃₆VD of voltage-stabilizing tube₃₆Negative electrode and MOS transistor VT₂₂After the drain electrode of the voltage stabilizing tube VD is connected₃₆The positive electrode of (2) is grounded;

MOS tube VT₂₂The source electrode of the MOS transistor is connected with a second resistor and an MOS transistor VT₂₂The second resistor is grounded;

the second circuit further comprises a third circuit connected to the driving chip U₁₅U of (1)_15-ENA pin;

driving chip U₁₅U of (1)_15-VCCPin and U_15-GNDA first capacitor is connected in parallel between the pins.

Preferably, the resistance R₁₈₁Is 10K.

Preferably, the capacitance C₁₆₄Has a capacity value of 2.2 microfarads.

Preferably, the resistance R₁₈₃Is 10K.

Preferably, the resistance R₁₈₂Is 10K.

Preferably, the resistance R₁₇₈The resistance value of (3) is 6.2K.

Preferably, the resistor R comprises 82K₁₁₃And a resistance R of 200K₁₁₂。

Preferably, the second resistor comprises a resistor R of 10K₁₇₉And a resistance R of 51K₁₈₀。

Preferably, the third circuit comprises a diode U₃₀Diode U₃₀Positive electrode and driving chip U₁₅U of (1)_15-ENPin connection, diode U₃₀Negative electrode and driving chip U_15-EN-RCPin connection via the driver chip U_15-EN-RCA voltage stabilizing tube VD is connected behind the pin₄₄VD of voltage-stabilizing tube₄₄And diode U₃₀Is connected with the negative electrode of a voltage stabilizing tube VD₄₄The anode of the voltage stabilizing tube VD is grounded₄₄Both ends of which are connected in parallel with a capacitor C₁₁₅；

Diode U₃₀Are connected in parallel with a resistor R₁₆₁Diode U₃₀The positive electrode of the capacitor is connected with a capacitor C₁₅₉Via a capacitor C₁₅₉And then grounded.

Preferably, the capacitor one comprises a capacitor C connected in parallel₁₂₇And a capacitor C₁₂₈。

The working principle of the circuit of the utility model is as follows:

when inputtingV_inWhen power is supplied and the input voltage continuously rises, the input voltage passes through the resistor R₁₁₂,R₁₁₃,R₁₇₈,R₁₇₉,R₁₈₀Voltage dividing and driving chip U₁₅Detecting U₁₅__ENSignal when U₁₅__ENWhen the voltage exceeds the threshold voltage of the driving chip, the driving chip U₁₅Starting to work; driving chip U₁₅In operation, VCC₁The voltage of rated DC12V is given from the inside of the chip and passes through R₁₈₂,VD₃₇,VD₃₈,R₁₈₃Voltage division of the related devices, the generated voltage division passing through a current limiting resistor R₁₈₁Driving MOS transistor VT₂₂Make the resistance R₁₇₈In a short-circuited state, thereby changing U₁₅__ENVoltage of (2), voltage at this time is compared with non-short-circuited resistance R₁₇₈The voltage is higher, thus achieving a voltage reduction at the turn-off point, which is equivalent to the resistor R₁₇₈The partial pressure occupied by the series connection is large.

When the input voltage starts to decrease, U₁₅__ENThe series voltage division also begins to decrease when triggering U₁₅When the threshold voltage is enabled, U₁₅Off, thus VCC₁The output is also turned off, VT₂₂Off, which means that the resistance R is₁₇₈Connected in series in the circuit again, if it is about to start up U₁₅A higher input voltage is required. Thereby realizing the voltage difference between startup and shutdown.

When the hysteresis voltage is to be set, i.e. the voltage difference between the power-on point and the power-off point, only the appropriate resistor R is selected₁₇₈And (4) finishing.

The utility model controls the input detection on-off voltage to enable the series resistor to realize the voltage difference (hysteresis voltage) of the on-off point by the existence of the power supply voltage of the chip, thereby avoiding the repeated on-off of the mainboard power supply caused by the voltage difference of the battery load and the no-load. The circuit adopts a power supply enabling scheme consisting of simple peripheral circuits to replace an operational amplifier hysteresis scheme; and the hysteresis voltage can be flexibly set according to requirements. The input enable hysteresis function is realized by using a combination and collocation mode of a voltage regulator tube, a resistor, a MOSFET and a driving chip; the hysteresis voltage range can be realized by changing the resistance value of the control resistor according to the requirement.

The above-mentioned embodiments only express a certain implementation mode of the present invention, and the description thereof is specific and detailed, but not construed as limiting the scope of the present invention; it should be noted that, for those skilled in the art, without departing from the concept of the present invention, several variations and modifications can be made, which are within the protection scope of the present invention; therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims (10)

1. An input enable hysteresis protection circuit, the circuit comprising a first circuit and a second circuit,

the first circuit comprises a MOS transistor VT₂₂The second circuit comprises a driving chip U₁₅；

The MOS transistor VT₂₂Is connected with a driving chip U₁₅And the driving chip U_15-EN-RCThe pin is connected;

the MOS transistor VT₂₂The grid electrode of the grid electrode is connected with a resistor R in sequence₁₈₁And a capacitor C₁₆₄Then grounding;

the capacitor C₁₆₄Are connected in parallel with a resistor R₁₈₃Said capacitor C₁₆₄The other end far away from the grounding end is sequentially connected with a voltage stabilizing tube VD₃₈、VD₃₇Resistance R₁₈₂Then connect to VCC₁；

The MOS transistor VT₂₂Is connected with a resistor R between the drain electrode and the source electrode₁₇₈Said MOS transistor VT₂₂The drain electrode of the MOS transistor is connected with a first resistor, and the MOS transistor VT₂₂Is connected to the driving chip U through the resistor_15-VINA pin;

the MOS transistor VT₂₂The drain electrode is connected with a voltage stabilizing tube VD₃₆The voltage stabilizing tube VD₃₆And the MOS transistor VT₂₂After the drain electrode of the voltage stabilizing tube VD is connected₃₆The positive electrode of (2) is grounded;

the MOS transistor VT₂₂The source electrode of the MOS transistor is connected with a second resistor, and the MOS transistor VT₂₂Grounding after passing through the second resistor;

the second circuit further comprises a third circuit connected to the driving chip U₁₅U of (1)_15-ENA pin;

the driving chip U₁₅U of (1)_15-VCCPin and U_15-GNDA first capacitor is connected in parallel between the pins.

2. The input-enabled hysteretic protection circuit of claim 1, wherein said resistor R₁₈₁Is 10K.

3. The input-enabled hysteretic protection circuit of claim 1, wherein said capacitor C₁₆₄Has a capacity value of 2.2 microfarads.

4. The input-enabled hysteretic protection circuit of claim 1, wherein said resistor R₁₈₃Is 10K.

5. The input-enabled hysteretic protection circuit of claim 1, wherein said resistor R₁₈₂Is 10K.

6. The input-enabled hysteretic protection circuit of claim 1, wherein said resistor R₁₇₈The resistance value of (3) is 6.2K.

7. The input-enabled hysteretic protection circuit of claim 1, wherein said resistor-R comprises 82K₁₁₃And a resistance R of 200K₁₁₂。

8. The input-enabled hysteretic protection circuit of claim 1, wherein said second resistor comprises a 10K resistor R₁₇₉And a resistance R of 51K₁₈₀。

9. The input-enabled hysteretic protection circuit of claim 1, wherein said third circuit comprises a diode U₃₀Said diode U₃₀And the driving chip U₁₅U of (1)_15-ENPin connection, the diode U₃₀And the negative electrode of the driving chip U_15-EN-RCPin connection via the driver chip U_15-EN-RCA voltage stabilizing tube VD is connected behind the pin₄₄The voltage stabilizing tube VD₄₄And the cathode of the diode U₃₀Is connected with the negative electrode of the voltage stabilizing tube VD₄₄The anode of the voltage stabilizing tube VD is grounded₄₄Both ends of which are connected in parallel with a capacitor C₁₁₅；

The diode U₃₀Are connected in parallel with a resistor R₁₆₁Said diode U₃₀The positive electrode of the capacitor is connected with a capacitor C₁₅₉Via said capacitor C₁₅₉And then grounded.

10. The input-enabled hysteretic protection circuit of claim 1, wherein said capacitor-one comprises a capacitor C in parallel₁₂₇And a capacitor C₁₂₈。

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