Utility model content
For overcoming above-mentioned the deficiencies in the prior art; the purpose of this utility model is to provide and prevents the full guard such as error-polarity connection, input overvoltage or under-voltage, overcurrent, and have realize simple, pressure drop is low, low in energy consumption, respond a kind of low pressure drop low-power dissipation power supply protective circuit of the effect such as timely.
For achieving the above object, the technical solution of the utility model is: a kind of low pressure drop low-power dissipation power supply protective circuit, this circuit is by metal-oxide-semiconductor Q1, metal-oxide-semiconductor Q2, Transient Suppression Diode D1, voltage stabilizing didoe D2, power protection chip U1 and some resistance and electric capacity composition, wherein Vin is input voltage, it is product power input interface, Vout is protective circuit output voltage, Transient Suppression Diode D1 is parallel to the most prime of power supply input, power supply is connected to the D level of metal-oxide-semiconductor Q1 after the surge protection of diode D1, the G level contact resistance R1 of metal-oxide-semiconductor Q1 is to power cathode, connect the positive pole of positive pole to power supply of diode D2 simultaneously, metal-oxide-semiconductor Q1, resistance R1 and voltage stabilizing didoe D2 forms the circuit of anti-error-polarity connection of power supply, the positive source exported through the S level of metal-oxide-semiconductor Q1 is connected to the D level of metal-oxide-semiconductor Q2, the G level of metal-oxide-semiconductor Q2 is connected to 10 pin of power protection chip U1, resistance R2, resistance R3, resistance R4 is connected between the both positive and negative polarity of power supply after connecting, and be connected respectively to 3 pin and 4 pin of power protection chip U1, electric capacity C1 and electric capacity C2 is connected in parallel, resistance R5 connects 5 pin of positive source and power protection chip U1, 2 pin of power protection chip U1 are directly connected to positive source, resistance R6, resistance R7, resistance R8 connects 1 pin of positive source to power protection chip U1 respectively, 9 pin, 8 pin, electric capacity C3 is connected between 6 pin of power protection chip U1 and 7 pin.
The beneficial effect of the utility model employing technique scheme is: a kind of low pressure drop low-power dissipation power supply protective circuit that the utility model product can provide; on power link; only have two metal-oxide-semiconductor Q1 and Q2, there is no many devices such as the diode of conventional protection circuit, sample circuit, fuse.The conducting resistance of usual metal-oxide-semiconductor, in milliohm rank, is about several milliohm, and the link pressure drop that conducting resistance causes thus is about several millivolt, substantially negligible, is therefore specially adapted in the low electronic product of powered battery, operating voltage.In normal operating conditions, D1, D2 are all in cut-off state, do not have current drain.U1 itself adopts low-power chip, and is operated in wake-up pattern, is in resting state under normal circumstances, power consumption is only microampere order, when there being abnormity of power supply to occur, by abnormality detection pin triggering work, the several milliampere of operating current, recovers normal rear from being advanced into resting state.Resistance R1, R2 and R3 can select the resistance of mega-ohms, and power consumption is also in microampere rank.
Embodiment
Below in conjunction with drawings and Examples, the utility model is further described, but does not form any restriction of the present utility model.
As shown in Figure 1, a kind of low pressure drop low-power dissipation power supply protective circuit, this circuit is by metal-oxide-semiconductor Q1, and metal-oxide-semiconductor Q2, Transient Suppression Diode D1, voltage stabilizing didoe D2, power protection chip U1 and some resistance and electric capacity form,
Wherein Vin is input voltage, and be product power input interface, Vout is protective circuit output voltage, provides level power supply after product.
Transient Suppression Diode D1 is parallel to the most prime of power supply input; power supply is connected to the D level of metal-oxide-semiconductor Q1 after the surge protection of Transient Suppression Diode D1; exported by the S level of metal-oxide-semiconductor Q1; the G level contact resistance R1 of metal-oxide-semiconductor Q1 is to power cathode; connect the positive pole of positive pole to power supply of voltage stabilizing didoe D2, metal-oxide-semiconductor Q1, resistance R1 and voltage stabilizing didoe D2 form the circuit of anti-error-polarity connection of power supply simultaneously.
The positive source exported through the S level of metal-oxide-semiconductor Q1 is connected to the D level of metal-oxide-semiconductor Q2; export to late-class circuit by the S level of metal-oxide-semiconductor Q2 to use; the G level of metal-oxide-semiconductor Q2 is connected to 10 pin of power protection chip U1, sends the conducting of signal controlling metal-oxide-semiconductor Q2 and overvoltage and under-voltage protection function are played in cut-off by power protection chip U1.
Resistance R2, resistance R3, resistance R4 are connected between the both positive and negative polarity of power supply after connecting; these 3 resistance arrange the threshold value of overvoltage, under-voltage protection point; be connected respectively to 3 pin and 4 pin of power protection chip U1, electric capacity C1 in parallel and electric capacity C2, for eliminating power supply disturbance, avoids protection exception.
Resistance R5 connects 5 pin of positive source and power protection chip U1, and enable power protection chip U1 is in normal operating conditions, and 2 pin of power protection chip U1 are directly connected to positive source, provide the power supply of power protection chip U1 need of work.
Resistance R6, resistance R7, resistance R8 connect 1 pin, 9 pin, 8 pin of positive source to power protection chip U1 respectively, and these 3 resistance provide power protection chip U1 to detect the signal of electric current needs, complete overcurrent protection function.
Electric capacity C3 is connected between 6 pin of power protection chip U1 and 7 pin, can be arranged the response time of the protection act of power protection chip U1 by electric capacity C3, is used for the demand of satisfied different occasion.
Power supply is supplied to the use of product rear class through metal-oxide-semiconductor Q1 and metal-oxide-semiconductor Q2 under normal circumstances.When power supply input error-polarity connection, metal-oxide-semiconductor Q1 turns off voluntarily.Thus loop of cutting off the electricity supply, protection rear class is in the unlikely damage of isolation, simultaneously owing to directly having cut off electric power loop, also plays a protective role to input power.D1 is that Transient Suppression Diode can effectively suppress the interference such as power surge, electrostatic.D2 is voltage stabilizing didoe, shields to metal-oxide-semiconductor Q1 when error-polarity connection of power supply.
When occur input voltage too high or too low time; by the magnitude of voltage the 3rd pin and the 4th pin being detected of power protection chip U1; send instruction in time and turn off metal-oxide-semiconductor Q2; protection late-class circuit is not damaged; when after power up to normal range (NR), automatically open metal-oxide-semiconductor Q2 and ensure that late-class circuit normally works.Resistance R2, resistance R3, resistance R4 can select different resistances as required, thus arrange different overvoltages, under-voltage protection point flexibly.Electric capacity C1, electric capacity C2 can effectively filter out power interference, ensure that circuit can not misoperation, and resistance and the suitable parameter of capacitance selection ensure that Circuit responce is timely.
When rear class short circuit occurring and causing overcurrent, the 1st and the 9th pin abnormal condition detected by power protection chip U1, turn off metal-oxide-semiconductor Q2 in time, thus link of cutting off the electricity supply, protection rear class and input power, when after failture evacuation, recover normal operating conditions voluntarily.
A main feature of this circuit is low pressure drop, on power link, only has two metal-oxide-semiconductor Q1 and Q2, does not have many devices such as the diode of conventional protection circuit, sample circuit, fuse.The conducting resistance of usual metal-oxide-semiconductor, in milliohm rank, is about several milliohm, and the link pressure drop that conducting resistance causes thus is about several millivolt, substantially negligible, is therefore specially adapted in the low electronic product of powered battery, operating voltage.
Another main feature of this circuit is low-power consumption, and in normal operating conditions, Transient Suppression Diode D1, voltage stabilizing didoe D2 are all in cut-off state, do not have current drain.Power protection chip U1 itself adopts low-power chip, and is operated in wake-up pattern, is in resting state under normal circumstances; power consumption is only microampere order, when there being abnormity of power supply to occur, by abnormality detection pin triggering work; the several milliampere of operating current, recovers normal rear from being advanced into resting state.Resistance R1, resistance R2 and resistance R3 can select the resistance of mega-ohms, and power consumption is also in microampere rank.
Therefore, in normal operating conditions, this circuit power consumption is extremely low, is specially adapted to battery power consumption and has in the electronic product of requirement power consumption.
The technical staff of the industry should understand; the utility model is not restricted to the described embodiments; what describe in above-described embodiment and specification just illustrates principle of the present utility model; under the prerequisite not departing from the utility model spirit and scope; the utility model also has various changes and modifications, and these changes and improvements all fall within the scope of claimed the utility model.