CN107425506B - Multi-path power supply protection circuit - Google Patents
Multi-path power supply protection circuit Download PDFInfo
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- CN107425506B CN107425506B CN201710801328.7A CN201710801328A CN107425506B CN 107425506 B CN107425506 B CN 107425506B CN 201710801328 A CN201710801328 A CN 201710801328A CN 107425506 B CN107425506 B CN 107425506B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/20—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess voltage
- H02H3/207—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess voltage also responsive to under-voltage
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/20—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess voltage
- H02H3/202—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess voltage for dc systems
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/24—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to undervoltage or no-voltage
- H02H3/243—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to undervoltage or no-voltage for DC systems
Abstract
The invention discloses a multi-path power supply protection circuit, which comprises an over-voltage and under-voltage detection circuit, a control circuit and a switch circuit, wherein the over-voltage and under-voltage detection circuit is connected with the control circuit; the output end of the over-voltage and under-voltage detection circuit is connected with the control circuit, a plurality of input ends of the over-voltage and under-voltage detection circuit are respectively connected with the output end of each power chip to be detected and used for monitoring each power chip to be detected, and the over-voltage and under-voltage detection circuit outputs a first control signal and a second control signal when any power chip is abnormal; the control circuit is connected with the switch circuit and used for receiving and keeping outputting a third control signal according to the first control signal and the second control signal, and the switch circuit superposes and cuts out the working voltage of each power supply chip to be detected to supply power according to the third control signal. The invention can not only protect the multi-path power supply at the same time, but also reduce the development cost and difficulty; and the power supply chip can be cut off in time to supply power to the rear-stage circuit, so that the rear-stage circuit is protected, and the safety is improved.
Description
Technical Field
The invention relates to the technical field of electronic circuits, in particular to a multi-path power supply protection circuit.
Background
In present electronic equipment, for satisfying the power supply demand of different electronic devices, generally all can select multichannel power supply, and in the debugging stage of equipment or in the middle of the use, phenomenons such as overflowing, short circuit can often appear, can lead to burning out of power chip to damage equipment. Therefore, it is necessary to add a protection circuit to the multi-path power supply.
The existing multi-path protection circuit scheme generally only adopts measures for individually protecting each power supply. For example, only one voltage is subjected to overvoltage protection, undervoltage protection, and the like, and the capability of monitoring and protecting a plurality of power supplies with different specification voltages appearing in a circuit at the same time is not provided. Therefore, the difficulty of protecting a plurality of power supply voltages is increased, the complexity and the cost of the whole design are caused, potential safety hazards exist, the power supply chip cannot be cut off in time to supply power to the rear-stage circuit, the fault is enlarged, and the rear-stage circuit is damaged.
Disclosure of Invention
The invention aims to provide a multi-path power supply protection circuit, which can protect multi-path power supplies simultaneously and reduce the development cost and difficulty; and the power supply chip can be cut off in time to supply power to the rear-stage circuit, so that the rear-stage circuit is protected, and the safety is improved.
The invention provides a multi-path power supply protection circuit, which comprises an over-voltage and under-voltage detection circuit, a control circuit and a switch circuit, wherein the over-voltage and under-voltage detection circuit is connected with the control circuit;
the output end of the over-voltage and under-voltage detection circuit is connected with the control circuit, a plurality of input ends of the over-voltage and under-voltage detection circuit are respectively connected with the output end of each power chip to be detected and are used for monitoring each power chip to be detected, and when any power chip is abnormal, the over-voltage and under-voltage detection circuit outputs a first control signal and a second control signal;
the control circuit is connected with the switch circuit and used for receiving a first control signal and a second control signal and keeping outputting a third control signal according to the first control signal and the second control signal;
and the input end of the switch circuit is respectively connected with the output end of each power supply chip to be detected, and the control end of the switch circuit is connected with the control circuit and is used for superposing and cutting out the working voltage of each power supply chip to be detected to supply power according to the third control signal.
As an implementation manner, the overvoltage and undervoltage detection circuit comprises a plurality of overvoltage detection modules, a plurality of undervoltage detection modules and a monitoring processing module;
the input end of each overvoltage detection module is correspondingly connected with the output end of each power supply chip to be detected, and the output end of each overvoltage detection module is connected with the input end of the control circuit; the overvoltage detection module is used for detecting whether the working voltage of each power supply chip to be detected is higher than the corresponding voltage threshold value or not, and when the working voltage is higher than the corresponding voltage threshold value, the corresponding overvoltage detection module outputs an overvoltage signal;
the input end of each under-voltage detection module is correspondingly connected with the output end of each power supply chip to be detected, and the output end of each under-voltage detection module is connected with the input end of the control circuit; the undervoltage detection module is used for detecting whether the working voltage of each power supply chip to be detected is lower than a corresponding voltage threshold value or not, and when the working voltage is lower than the corresponding voltage threshold value, the corresponding undervoltage detection module outputs an undervoltage signal quickly;
the input end of the monitoring processing module is respectively connected with each overvoltage detection module and each undervoltage detection module, and the output end of the monitoring processing module is connected with the control circuit and used for outputting a first control signal and a second control signal when receiving the overvoltage signal and/or the undervoltage signal.
As an implementation manner, the overvoltage detection module includes a first DC/DC conversion unit, a first voltage division unit, and a first comparator;
the input end of the first DC/DC conversion unit is connected with the output end of the corresponding power supply chip to be detected, and the output end of the first DC/DC conversion unit is connected with the first voltage division unit and is used for performing DC/DC conversion on the working voltage output by the power supply chip;
the first voltage division unit is connected with the input end of the first comparator and used for dividing the converted working voltage and outputting a divided voltage;
the first comparator is used for comparing the divided voltage with a preset voltage threshold value, and outputting an overvoltage signal when the divided voltage is higher than the voltage threshold value.
As one possible embodiment, the first voltage division unit includes a resistor R1 and a resistor R2;
the resistor R1 has one end connected to the first DC/DC conversion unit and the other end connected to the first comparator and one end of the resistor R2, respectively;
the other end of the resistor R2 is grounded.
As an implementation manner, the undervoltage detection module and the monitoring processing module are monitoring processor modules;
the monitoring processor module is used for detecting whether the working voltage of each power supply chip to be detected is lower than a corresponding voltage threshold value, and when the working voltage is lower than the corresponding voltage threshold value, the corresponding under-voltage detection module quickly outputs an under-voltage signal; and receiving the overvoltage signal, and outputting a first control signal and a second control signal by the monitoring processing module according to the overvoltage signal and/or the undervoltage signal.
As one possible implementation, the control circuit includes a first double-inverting schmitt trigger circuit, an edge D trigger circuit, a logic and gate circuit, and a second double-inverting schmitt trigger circuit;
the control circuit comprises a first double-reverse-phase Schmitt trigger circuit, an edge D trigger circuit, a logic AND gate circuit and a second double-reverse-phase Schmitt trigger circuit which are sequentially connected;
the first double-inverse-phase Schmitt trigger circuit is used for receiving a second control signal and keeping outputting a first level signal according to the second control signal;
the edge D flip-flop circuit is used for receiving the first control signal and the first level signal and keeping outputting a second level signal according to the first control signal and the first level signal;
the logic AND gate circuit is used for receiving the second level signal and outputting a third level signal according to the second level signal;
and the second double-inverting Schmitt trigger circuit is used for receiving the third level signal and outputting a third control signal according to the third level signal.
As one possible implementation, the first double-inverting schmitt trigger circuit includes a first schmitt trigger, a delay circuit, and a second schmitt trigger;
the first Schmitt trigger, the delay circuit and the second Schmitt trigger are sequentially connected.
As one possible implementation, the delay circuit includes a diode D7, a resistor R13, and a capacitor C28;
the diode D7 is connected in parallel with the resistor R13, the anode of the diode D7 is respectively connected with one end of the capacitor C28 and the second Schmitt trigger, and the cathode of the diode D7 is connected with the first Schmitt trigger;
the other end of the capacitor C28 is grounded.
As one possible implementation, the switch circuit includes a resistor R7, a transistor Q2, a second voltage division unit, and a MOS transistor Q1;
the resistor R7, one end of which is connected with the control circuit and the other end of which is connected with the base stage of the transistor Q2;
the transistor Q2, the emitter of which is grounded, and the collector of which is connected with the first input end of the second voltage division unit;
the second input end of the second voltage division unit is respectively connected with the output end of each power chip to be detected and the source S of the MOS transistor Q1, and the output end of the second voltage division unit is connected with the grid G of the MOS transistor Q1;
and the drain D of the MOS transistor Q1 is used as an output end.
As an implementation, the second voltage division unit includes a resistor R4 and a resistor R5;
one end of the resistor R4 is respectively connected with the output end of each power chip to be detected and the source S of the MOS tube Q1, and the other end of the resistor R4 is respectively connected with the grid G of the MOS tube Q1 and one end of the resistor R5;
the other end of the resistor R5 is connected to the collector of the transistor Q2.
Compared with the prior art, the technical scheme has the following advantages:
the multi-path power supply protection circuit provided by the invention is connected with the output end of each power supply chip to be detected through the over-voltage and under-voltage detection circuit, and when any one power supply chip is abnormal, the over-voltage and under-voltage detection circuit outputs a first control signal and a second control signal; the control circuit is connected with the switch circuit and used for receiving and keeping outputting a third control signal according to the first control signal and the second control signal, and the switch circuit superposes and cuts out the working voltage of each power supply chip to be detected to supply power according to the third control signal. The invention can not only protect the multi-path power supply at the same time, but also reduce the development cost and difficulty; and the power supply chip can be cut off in time to supply power to the rear-stage circuit, so that the rear-stage circuit is protected, and the safety is improved.
Drawings
Fig. 1 is a schematic structural diagram of a multi-path power protection circuit according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of the under-voltage detection circuit shown in FIG. 1;
FIG. 3 is a schematic diagram of the control circuit of FIG. 1;
fig. 4 is a schematic structural diagram of the switch circuit in fig. 1.
In the figure: 1. an over-voltage and under-voltage detection circuit; 2. a control circuit; 21. a first double-inverting Schmitt trigger circuit; 22. an edge D flip-flop circuit; 23. a logic AND gate circuit; 24. a second double-inverting Schmitt trigger circuit; 3. a switching circuit.
Detailed Description
The above and further features and advantages of the present invention will be apparent from the following, complete description of the invention, taken in conjunction with the accompanying drawings, wherein the described embodiments are merely some, but not all embodiments of the invention.
Referring to fig. 1, a multi-channel power protection circuit according to a first embodiment of the present invention includes an over-voltage and under-voltage detection circuit 1, a control circuit 2, and a switch circuit 3;
the overvoltage and undervoltage detection circuit 1 is connected with the control circuit 2 at the output end, and a plurality of input ends of the overvoltage and undervoltage detection circuit are respectively connected with the output end of each power chip to be detected and used for monitoring each power chip to be detected, and when any power chip is abnormal, the overvoltage and undervoltage detection circuit 1 outputs a first control signal and a second control signal;
the control circuit 2 is connected with the switch circuit 3 and used for receiving the first control signal and the second control signal and keeping outputting a third control signal according to the first control signal and the second control signal;
and the input end of the switch circuit 3 is connected with the output end of each power supply chip to be detected, and the control end of the switch circuit is connected with the control circuit 2 and used for switching the working voltage of each power supply chip to be detected into a power supply in a superposition mode according to the third control signal.
It should be noted that each power chip to be detected superposes all the operating voltages of each power chip to be detected and then supplies power to the subsequent circuits, and when any one of the power chips to be detected is abnormal, such as overvoltage, undervoltage or short circuit, the overvoltage and undervoltage detection circuit 1 can timely detect and feed back the first control signal and the second control signal; so that the control circuit 2 keeps outputting the third control signal, cuts off the power supply to the subsequent circuit, protects the subsequent circuit, and prevents the fault from further expanding.
The overvoltage and undervoltage detection circuit 1 comprises a plurality of input ends, and output ends of the input ends can be combined to one position to output a first control signal and a second control signal; or two paths are adopted, wherein one path is used for outputting the first control signal, and the other path is used for outputting the second control signal. The control circuit 2 makes the output end of the first control signal reversely output the third control signal according to the first control signal, and the second control signal makes the output third control signal keep the level, for example, the second control signal makes the output low level signal continuously after the reverse output, so as to ensure that the power supply to the subsequent circuit is cut off in time.
The multi-path power supply protection circuit provided by the invention is connected with the output end of each power supply chip to be detected through the over-voltage and under-voltage detection circuit 1, and when any one power supply chip is abnormal, the over-voltage and under-voltage detection circuit 1 outputs a first control signal and a second control signal; the control circuit 2 is connected with the switch circuit 3, and is used for receiving and keeping outputting a third control signal according to the first control signal and the second control signal, and the switch circuit 3 superposes and cuts out the working voltage of each power supply chip to be detected according to the third control signal. The invention can not only protect the multi-path power supply at the same time, but also reduce the development cost and difficulty; and the power supply chip can be cut off in time to supply power to the rear-stage circuit, so that the rear-stage circuit is protected, and the safety is improved.
The circuit parts of the present invention are explained in detail below:
it should be noted that the overvoltage and undervoltage detection circuit 1 may include a plurality of overvoltage detection modules, a plurality of undervoltage detection modules, and a monitoring processing module;
the input end of each overvoltage detection module is correspondingly connected with the output end of each power supply chip to be detected, and the output end of each overvoltage detection module is connected with the input end of the control circuit 2; the overvoltage detection module is used for detecting whether the working voltage of each power supply chip to be detected is higher than the corresponding voltage threshold value or not, and when the working voltage is higher than the corresponding voltage threshold value, the corresponding overvoltage detection module outputs an overvoltage signal;
the input end of each under-voltage detection module is correspondingly connected with the output end of each power supply chip to be detected, and the output end of each under-voltage detection module is connected with the input end of the control circuit 2; the undervoltage detection module is used for detecting whether the working voltage of each power supply chip to be detected is lower than a corresponding voltage threshold value or not, and when the working voltage is lower than the corresponding voltage threshold value, the corresponding undervoltage detection module quickly outputs an undervoltage signal;
and the input end of the monitoring processing module is respectively connected with each overvoltage detection module and each undervoltage detection module, and the output end of the monitoring processing module is connected with the control circuit 2 and is used for outputting a first control signal and a second control signal when receiving an overvoltage signal and/or an undervoltage signal.
The overvoltage detection module comprises a first DC/DC conversion unit, a first voltage division unit and a first comparator; the input end of the first DC/DC conversion unit is connected with the output end of the corresponding power chip to be detected, and the output end of the first DC/DC conversion unit is connected with the first voltage division unit and is used for performing DC/DC conversion on the working voltage output by the power chip; the first voltage division unit is connected with the input end of the first comparator and used for dividing the converted working voltage and outputting a divided voltage; and the first comparator is used for comparing the divided voltage with a preset voltage threshold value and outputting an overvoltage signal when the divided voltage is higher than the voltage threshold value. Simple structure, it is quick to detect the reflection. The specific composition of the undervoltage detection module is consistent with that of the overvoltage detection module, and the difference between the undervoltage detection module and the overvoltage detection module is that the divided voltage of the undervoltage detection module is compared with a preset voltage threshold by a comparator, and when the divided voltage of the undervoltage detection module is lower than the voltage threshold, an undervoltage signal is output.
The first voltage division unit comprises a resistor R1 and a resistor R2; a resistor R1 having one end connected to the first DC/DC conversion unit and the other end connected to the first comparator and one end of the resistor R2, respectively; the other end of the resistor R2 is connected to ground. The resistor is formed by connecting two resistors in series, and the resistance values of the two resistors are changed according to different requirements; for example, the resistance values are 15K and 3K respectively, the precision is 1%, and the method is used for monitoring that the voltage of the input end exceeds +3.3VDIS to +3.6 VDIS; the resistance values are respectively 25K and 3K, the precision is 1 percent, and the device is used for monitoring the voltage of the input end, wherein the voltage of +5V exceeds + 5.6V; the resistance values are respectively 43K and 2K, the precision is 1 percent, and the device is used for monitoring the voltage of the input end, wherein the voltage of +12V exceeds + 13.6V. The first partial pressure unit has wide application range and reduces the production cost.
The overvoltage and undervoltage detection circuit 1 can also comprise a plurality of overvoltage detection modules and a monitoring processor module; the input end of each overvoltage detection module is correspondingly connected with the output end of each power supply chip to be detected, and the output end of each overvoltage detection module is connected with the input end of the monitoring processor module; the overvoltage detection module is used for detecting whether the working voltage of each power supply chip to be detected is higher than the corresponding voltage threshold value or not, and when the working voltage is higher than the corresponding voltage threshold value, the corresponding overvoltage detection module outputs an overvoltage signal; the monitoring processor module comprises monitoring processor chips and peripheral circuits thereof and is used for detecting whether the working voltage of each power supply chip to be detected is lower than a corresponding voltage threshold value or not, and when the working voltage is lower than the corresponding voltage threshold value, the corresponding under-voltage detection module quickly outputs an under-voltage signal; and receiving the overvoltage signal, and outputting a first control signal and a second control signal by the monitoring processing module according to the overvoltage signal and/or the undervoltage signal.
For example, the undervoltage detection circuit 1 for detecting multiple power supplies with different voltages is described, and the voltages of the power supplies are +5V, +12V, + 3.3V; the voltage of the main power supply group consisting of them is 25V.
Fig. 2 is a schematic structural diagram of the undervoltage detection circuit 1; the device is provided with 4 overvoltage detection modules, and main chips adopted by the device are U9, U11, U12 and U13, and are voltage comparators ADCMP350 packaged into SC-70; wherein, pin 1 is an inverse analog voltage input terminal, pin 2 is a ground, pin 3 is a digital open-drain output terminal, and pin 4 is a power input terminal. The ADCMP350 chip has a +0.6V reference voltage inside. When the input voltage at the inverting terminal of pin 1 of the ADCMP350 is higher than the internal +0.6V, pin 3 outputs a low level, otherwise it remains high. The voltage dividing circuit comprises a resistor R14 and a resistor R17, the resistance values of the resistor R14 and the resistor R17 are 15K and 3K respectively, the precision is 1%, and once the voltage of the input end exceeds 3.3V and exceeds 3.6V, the voltage of the resistor R17 exceeds +0.6V and is higher than the internal reference voltage of ADCMP350 and +0.6V, the 3-pin output end outputs low level. Similarly, the other three circuits are respectively used for monitoring +12V, +5V, +3.3VDIS, wherein the resistance values of the resistor R21 and the resistor R22 are respectively 15K and 3K, the precision is 1%, and the circuits are used for monitoring that the +3.3VDIS exceeds +3.6VDIS at the input end voltage; the resistance values of the resistor R23 and the resistor R24 are 25K and 3K respectively, the precision is 1%, and the device is used for monitoring the voltage of the input end, wherein the voltage of +5V exceeds + 5.6V; the resistance values of the resistor R19 and the resistor R20 are 43K and 2K respectively, the accuracy is 1%, and the device is used for monitoring the voltage of the input end, wherein the voltage of +12V exceeds + 13.6V. In other embodiments, the reference voltage access 5 pin may be externally disposed, and is not limited herein. The capacitors C25, C27, C30, C31 and C32 are all 100nF/50V for input power supply terminal filtering.
The monitoring processor module comprises a power supply voltage monitoring processor chip TPS3307-33DR packaged as MSOP-8 by U10. The pins 1, 2 and 3 of the U10 are used for monitoring three power supply voltages of +5V, +3.3V, +12V, voltage division circuits are arranged in the pins 1 and 2, undervoltage set values are respectively 4.55V and 2.93V, and reference voltage of 1.25V is arranged in the pin 3. Pin 5 is the active low level reset output and pin 6 is the active high level reset output. Pin 7 is the effective manual reset input of low level, pin 8 is the power end, and pin 4 is ground.
The working principle is that when any one of the power supply voltages +3.3V, +3.3VDIS, +5V and +12V in the four-way overvoltage detection module exceeds the +0.6V reference voltage in the ADCMP350 after being divided by resistors, the 3 pin of the ADCMP350 outputs a low level to the 7 pin of the U10
Middle, 7 feet
At low level, 5 pins
Output low and 6-pin RST high. At the same time, when
When the voltage is high level, if any one of the +3.3V, +5V, +12V of the power supply voltage is lower than the 1-pin internal reference voltage value of 4.55V in TPS3307-33DR, the 2-pin internal reference voltage value is 2.93V, and the voltage value of the voltage dividing circuit formed by the resistance value of the external resistor R15 being 910K with the precision of 1% and the resistance value of the external resistor R18 being 160K with the precision of 1% is lower than that of the 3-pin internal reference voltage valueWhen the quasi-voltage value is 1.25V, 5 pins
Output low and 6-pin RST high. Once any voltage of +5V, +12V, +3.3VDIS exceeds or is lower than the threshold voltage that sets for, will cut off the main power supply and prevent the trouble from expanding further, protect the circuit of the subsequent stage; the short circuit caused by artificial misoperation of two adjacent different voltage values or the short circuit caused by the defects of the device can also cut off the main power supply to prevent the fault from further expanding, so as to protect a rear-stage circuit; the used devices are small packages (SC-70, SOT-23), the cost is low, and the area of the circuit board is not influenced at all.
Further, the control circuit 2 includes a first double-inverting schmitt trigger circuit 21, an edge D trigger circuit 22, a logic and gate circuit 23, and a second double-inverting schmitt trigger circuit 24; the control circuit 2 comprises a first double-inversion Schmitt trigger circuit 21, an edge D trigger circuit 22, a logic AND gate circuit 23 and a second double-inversion Schmitt trigger circuit 24 which are connected in sequence; a first double-inverting schmitt trigger circuit 21 for receiving the second control signal and keeping outputting the first level signal according to the second control signal; an edge D flip-flop circuit 22 for receiving the first control signal and the first level signal and keeping outputting the second level signal according to the first control signal and the first level signal; a logic and circuit 23, configured to receive the second level signal and output a third level signal according to the second level signal; and a second double-inverting schmitt trigger circuit 24 for receiving the third level signal and outputting a third control signal according to the third level signal. The feedback is sensitive, and when the logic and gate circuit 23 receives the second level signal, the output end outputs a low level no matter whether the input ends of the other two and gates are high level or not.
Further, the first double-inverting schmitt trigger circuit 21 includes a first schmitt trigger, a delay circuit, and a second schmitt trigger; the first Schmitt trigger, the delay circuit and the second Schmitt trigger are connected in sequence. The delay circuit comprises a diode D7, a resistor R13 and a capacitor C28; the diode D7 is connected with the resistor R13 in parallel, the anode of the diode D7 is respectively connected with one end of the capacitor C28 and the second Schmitt trigger, and the cathode of the diode D7 is connected with the first Schmitt trigger; the other end of the capacitor C28 is grounded.
For example, the control circuit 2 is described in detail, and fig. 3 is a schematic structural diagram of the control circuit 2; the first double-inverting schmitt trigger circuit 21 is a double-inverting schmitt trigger U7 and its peripheral circuits, the second double-inverting schmitt trigger circuit 24 is a double-inverting schmitt trigger U5 and its peripheral circuits, the edge D trigger circuit 22 is an edge D trigger SN74AUP1G74DCU packaged VSSOP-8 and its peripheral circuits, and the and logic circuit 23 is a three-input logic and gate chip SN74LVC1G11DBV packaged SC70-6 and its peripheral circuits. The main chips U7 and U5 are double-phase reverse Schmitt trigger SN74AUP2G14DCKR packaged SC70, wherein pins 1 and 3 are digital level input terminals, pins 4 and 6 are digital level reverse output terminals, pin 2 is ground, and pin 5 is a power supply terminal. If the input end is at high level, the inverted output end is at low level, otherwise, the output end is at high level. U8 is an edge D flip-flop SN74AUP1G74DCU package VSSOP-8, wherein 1 pin CLK triggers the clock signal input for rising edges, the high level is active; pin 2D is a data input; 3 feet
Is an inverted output end; 4, the pin is grounded; pin 5Q is an output end; 6 feet
To clear the input, the low level is active; 7 feet
The low level is active for a preset input; the 8-pin is a power supply end. U6 is a three-input logic AND gate chip SN74LVC1G11DBV package SC 70-6. Wherein, pin 1 is an A-terminal input, pin 3 is a B-terminal input, pin 6 is a C-terminal input, pin 2 is a ground, pin 4 is a Y-output terminal, and pin 5 is a power supply terminal. D7 and D8 are Schottky diodes BAT54T1G packaged as SOD-123; c26 and C28 are tantalum capacitors 10UF/10V packaged as SOD-123. Wherein the resistance of the resistor R16 is 1K and the capacitance of the capacitor C29 is 1nF/50V constitutes an RC delay circuit; the resistance value of the resistor R13 is 100K, the Schottky diode D7 is BAT54T1G, and the capacitance value of the tantalum capacitor C28 is 10UF/10V to form a delay circuit; the resistance of the resistor R12 is 680K, the Schottky diode D8 is BAT54T1G, and the capacitance of the tantalum capacitor C26 is 10UF/10V to form a filter circuit. The resistor R10 with the value of 10K and the capacitor C21 with the resistance value of 1NF/50V form a filter circuit. The capacitors C19, C20, C23 and C24 have the capacitance value of 100NF/50V and are used for power supply filtering.
When the working principle is normal starting, a pin A1 of U6 transmits a starting signal ON/OFF high level signal from an external display panel. Since all normal is started, pin 6 of U8
Clear input high, pin 7 of U8
The preset input end is changed from low level at the starting moment to high level through a delay circuit consisting of R12 and C26, a 2-pin D data input end of U8 and a 3-pin D data input end of U8
Are connected. At this time, the 1-pin CLK clock signal input of U8 is low, and the 5-pin Q of U8 outputs high. Since the 5 pin of U8 is connected to the 3 pin of U6, the 3 pin B input of U6 is high and the 6 pin C of U6 is the +3.3VDIS input on the external display panel. At this time, the Y terminal of pin 4 of U6 outputs high, and pin 4 of U5 is high by the double-inverted schmitt trigger.
When the overvoltage and undervoltage detection circuit 1 detects that any power supply chip is abnormal, the 6-pin RST of the U10 outputs high level, the 1-pin CK clock signal input end of the U8 is also changed into high level through a delay circuit composed of R16 and C29, the Q value of the 5-pin of the U8 is reversed, the high level is changed into low level, and meanwhile, the 5-pin of the U10 is changed into low level
The original high level is changed into low level, and the U7 double-inverting Schmitt trigger connected with the low level is connected with the 6 pin of the U8 through the C28 and R13 delay circuit
Are connected. Pin 6 of U8 goes low from high and further latches the Q value so that its output stays low. The 5-pin Q output of U8 is connected to 3-pin B of U6. At this time, the 4-pin Y output of U6 outputs low no matter whether pins 1 and 6 of the other two and gate inputs of U6 are high or not. With a double inverting schmitt trigger, pin 4 of U5 is also low.
The structure of the switch circuit 3 shown in fig. 4; the circuit comprises a resistor R7, a transistor Q2, a second voltage division unit and a MOS transistor Q1; a resistor R7 having one end connected to the control circuit 2 and the other end connected to the base of the transistor Q2; a transistor Q2, the emitter of which is grounded and the collector of which is connected to the first input terminal of the second voltage dividing unit; the second input end of the second voltage division unit is respectively connected with the output end of each power supply chip to be detected and the source S of the MOS transistor Q1, and the output end of the second voltage division unit is connected with the grid G of the MOS transistor Q1; and the drain D of the MOS transistor Q1 is used as an output end.
Further, the second voltage division unit comprises a resistor R4 and a resistor R5; one end of the resistor R4 is respectively connected with the output end of each power supply chip to be detected and the source S of the MOS tube Q1, and the other end of the resistor R4 is respectively connected with the grid G of the MOS tube Q1 and one end of the resistor R5; the other end of the resistor R5 is connected to the collector of the transistor Q2. Simple structure, the reliability is high, according to the partial pressure demand of difference, can in time dispose.
The operation principle of the switch circuit 3 is that when a switch is normally turned ON, the ON signal transmitted to the resistor R7 is at a high level, and the transistor NPN of the Q2 is turned ON. The +24V of the power supply terminal generates a positive tube voltage difference between the gate G and the source S of the P-channel enhancement type MOS transistor Q1 through a voltage division circuit composed of R2 and R5, thereby turning on the Q1 and enabling the circuit to work normally. Otherwise, the circuit is cut off; safe and reliable, response speed is fast.
Although the present invention has been described with reference to the preferred embodiments, it is not intended to limit the present invention, and those skilled in the art can make variations and modifications of the present invention without departing from the spirit and scope of the present invention by using the methods and technical contents disclosed above.
Claims (8)
1. A multi-path power supply protection circuit is characterized by comprising an over-voltage and under-voltage detection circuit, a control circuit and a switch circuit;
the output end of the over-voltage and under-voltage detection circuit is connected with the control circuit, a plurality of input ends of the over-voltage and under-voltage detection circuit are respectively connected with the output end of each power chip to be detected and are used for monitoring each power chip to be detected, and when any power chip is abnormal, the over-voltage and under-voltage detection circuit outputs a first control signal and a second control signal;
the control circuit is connected with the switch circuit and used for receiving a first control signal and a second control signal and keeping outputting a third control signal according to the first control signal and the second control signal;
the input end of the switch circuit is respectively connected with the output end of each power supply chip to be detected, and the control end of the switch circuit is connected with the control circuit and is used for superposing and cutting out the working voltage of each power supply chip to be detected to supply power according to the third control signal;
the control circuit comprises a first double-inversion Schmitt trigger circuit, an edge D trigger circuit, a logic AND gate circuit and a second double-inversion Schmitt trigger circuit;
the control circuit comprises a first double-reverse-phase Schmitt trigger circuit, an edge D trigger circuit, a logic AND gate circuit and a second double-reverse-phase Schmitt trigger circuit which are sequentially connected;
the first double-inverse-phase Schmitt trigger circuit is used for receiving a second control signal and keeping outputting a first level signal according to the second control signal;
the edge D flip-flop circuit is used for receiving the first control signal and the first level signal and keeping outputting a second level signal according to the first control signal and the first level signal;
the logic AND gate circuit is used for receiving the second level signal and outputting a third level signal according to the second level signal;
the second double-inverting Schmitt trigger circuit is used for receiving the third level signal and outputting a third control signal according to the third level signal;
the switch circuit comprises a resistor R7, a transistor Q2, a second voltage division unit and a MOS transistor Q1;
the resistor R7, one end of which is connected with the control circuit and the other end of which is connected with the base stage of the transistor Q2;
the transistor Q2, the emitter of which is grounded, and the collector of which is connected with the first input end of the second voltage division unit;
the second input end of the second voltage division unit is respectively connected with the output end of each power chip to be detected and the source S of the MOS transistor Q1, and the output end of the second voltage division unit is connected with the grid G of the MOS transistor Q1;
and the drain D of the MOS transistor Q1 is used as an output end.
2. The multi-channel power protection circuit of claim 1, wherein the over-voltage and under-voltage detection circuit comprises a plurality of over-voltage detection modules, a plurality of under-voltage detection modules and a monitoring processing module;
the input end of each overvoltage detection module is correspondingly connected with the output end of each power supply chip to be detected, and the output end of each overvoltage detection module is connected with the input end of the monitoring processing module; the overvoltage detection module is used for detecting whether the working voltage of each power supply chip to be detected is higher than the corresponding voltage threshold value or not, and when the working voltage is higher than the corresponding voltage threshold value, the corresponding overvoltage detection module outputs an overvoltage signal;
the input end of each under-voltage detection module is correspondingly connected with the output end of each power supply chip to be detected, and the output end of each under-voltage detection module is connected with the input end of the monitoring processing module; the undervoltage detection module is used for detecting whether the working voltage of each power supply chip to be detected is lower than a corresponding voltage threshold value or not, and when the working voltage is lower than the corresponding voltage threshold value, the corresponding undervoltage detection module outputs an undervoltage signal quickly;
the input end of the monitoring processing module is respectively connected with each overvoltage detection module and each undervoltage detection module, and the output end of the monitoring processing module is connected with the control circuit and used for outputting a first control signal and a second control signal when receiving the overvoltage signal and/or the undervoltage signal.
3. The multi-channel power protection circuit of claim 2, wherein the over-voltage detection module comprises a first DC/DC conversion unit, a first voltage division unit, and a first comparator;
the input end of the first DC/DC conversion unit is connected with the output end of the corresponding power supply chip to be detected, and the output end of the first DC/DC conversion unit is connected with the first voltage division unit and is used for performing DC/DC conversion on the working voltage output by the power supply chip;
the first voltage division unit is connected with the input end of the first comparator and used for dividing the converted working voltage and outputting a divided voltage;
the first comparator is used for comparing the divided voltage with a preset voltage threshold value, and outputting an overvoltage signal when the divided voltage is higher than the voltage threshold value.
4. The multi-channel power protection circuit of claim 3, wherein the first voltage division unit comprises a resistor R1 and a resistor R2;
the resistor R1 has one end connected to the first DC/DC conversion unit and the other end connected to the first comparator and one end of the resistor R2, respectively;
the other end of the resistor R2 is grounded.
5. The multi-channel power protection circuit of claim 2, wherein the under-voltage detection module and the monitor processing module are monitor processor modules;
the monitoring processor module is used for detecting whether the working voltage of each power supply chip to be detected is lower than a corresponding voltage threshold value, and when the working voltage is lower than the corresponding voltage threshold value, the corresponding under-voltage detection module quickly outputs an under-voltage signal; and receiving the overvoltage signal, and outputting a first control signal and a second control signal by the monitoring processing module according to the overvoltage signal and/or the undervoltage signal.
6. The multi-channel power protection circuit of claim 1, wherein the first dual inverting schmitt trigger circuit comprises a first schmitt trigger, a delay circuit, and a second schmitt trigger;
the first Schmitt trigger, the delay circuit and the second Schmitt trigger are sequentially connected.
7. The multi-channel power protection circuit as claimed in claim 6, wherein the delay circuit comprises a diode D7, a resistor R13, and a capacitor C28;
the diode D7 is connected in parallel with the resistor R13, the anode of the diode D7 is respectively connected with one end of the capacitor C28 and the second Schmitt trigger, and the cathode of the diode D7 is connected with the first Schmitt trigger;
the other end of the capacitor C28 is grounded.
8. The multi-channel power protection circuit of claim 1, wherein the second voltage dividing unit comprises a resistor R4 and a resistor R5;
one end of the resistor R4 is respectively connected with the output end of each power chip to be detected and the source S of the MOS tube Q1, and the other end of the resistor R4 is respectively connected with the grid G of the MOS tube Q1 and one end of the resistor R5;
the other end of the resistor R5 is connected to the collector of the transistor Q2.
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| CN111819103B (en) * | 2018-10-23 | 2024-01-12 | 深圳配天机器人技术有限公司 | Safety control system, control method and automobile |
| CN111327026A (en) * | 2020-02-27 | 2020-06-23 | 深圳市深智电科技有限公司 | Two-path direct current power supply circuit with overvoltage and undervoltage protection function and method |
| CN111431143A (en) * | 2020-04-24 | 2020-07-17 | 深圳市三旺通信股份有限公司 | Intrinsic safety type power supply circuit and intrinsic safety type communication network equipment |
| CN112054483B (en) * | 2020-08-04 | 2022-09-27 | 上海空间电源研究所 | Simple high-reliability overvoltage protection circuit |
| CN112069554A (en) * | 2020-09-18 | 2020-12-11 | 天津兆讯电子技术有限公司 | Power-on structure of external power supply, method thereof, security chip and electronic card |
| CN112115520A (en) * | 2020-09-18 | 2020-12-22 | 天津兆讯电子技术有限公司 | Internal power supply structure and method, safety chip and electronic card |
| CN115357108B (en) * | 2022-06-30 | 2023-04-11 | 广州创龙电子科技有限公司 | AM335x discrete power supply power-on and power-off time sequence control circuit and method |
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| CN203377584U (en) * | 2013-08-26 | 2014-01-01 | 三峡大学 | Three-phase non-midline phase-lack, undervoltage and overvoltage protection circuit |
| CN104300509B (en) * | 2014-10-31 | 2017-03-08 | 中颖电子股份有限公司 | It is applied to the under-voltage protection load latch cicuit of multiple li-ion cell protection schemes |
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