CN210404738U - Reverse connection prevention protection circuit for direct current input - Google Patents
Reverse connection prevention protection circuit for direct current input Download PDFInfo
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- CN210404738U CN210404738U CN201921307533.9U CN201921307533U CN210404738U CN 210404738 U CN210404738 U CN 210404738U CN 201921307533 U CN201921307533 U CN 201921307533U CN 210404738 U CN210404738 U CN 210404738U
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Abstract
The utility model provides a direct current input prevents reverse-connection protection circuit, include: the power supply comprises a power supply, a DC-DC power conversion circuit, an auxiliary power supply and an MOS (metal oxide semiconductor) tube, wherein the positive end of the power supply is connected with the first input end of the DC-DC power conversion circuit, the input end of the auxiliary power supply is connected with the first output end of the DC-DC power conversion circuit, the output end of the auxiliary power supply is connected with the third end of the MOS tube through a sixteenth resistor, the second end of the MOS tube is connected with the second input end of the DC-DC power conversion circuit, the second end of the MOS tube is also connected with the third end of the MOS tube through a seventeenth resistor, and the first end of the MOS tube is connected with the negative end of the power supply. The utility model discloses use auxiliary power source to remove opening of control MOS pipe, and auxiliary power source derives from DC-DC power conversion circuit, and its output is in a stable within range, the utility model discloses can be at the reliable drive MOS pipe of wideer voltage range, but also can work high-efficiently.
Description
Technical Field
The utility model belongs to the switching power supply class product of direct current input type especially relates to a direct current input prevents reverse-connection protection circuit.
Background
With the development and progress of battery technology, more and more electric equipment adopts direct current input for power supply. In general, a dc switching power supply, a driver, a frequency converter and the like built in the dc power supply equipment need to ensure the correctness of the polarity of an input power supply, and if the polarity is misconnected, the equipment is damaged and a safety accident is caused, so that the dc power supply equipment generally needs to be protected against reverse connection.
Referring to fig. 1, a conventional reverse connection protection circuit is provided, which uses a series diode for reverse connection protection, and has the main advantages of simple circuit and low cost, but the main disadvantages are that the forward conduction voltage drop of the diode is large, the power consumption is too large when the current is large, and the efficiency and heat dissipation are both large problems.
Referring to fig. 2, another conventional solution of an anti-reverse-connection protection circuit uses series-connected MOS transistors for anti-reverse-connection protection. Compared with the scheme of performing reverse connection prevention protection on the series diode in the figure 1, the scheme has the advantages that the conduction impedance of the MOS tube can be very low, the current technology can be several milliohms or even lower, the power consumption of the series diode in the circuit is very low, and the efficiency and the heat dissipation of the series diode are not problems in certain application occasions. However, the driving circuit of the MOS transistor gate is composed of three devices, i.e., a resistor R1', a resistor R2' and a zener diode D2', which simply divide and stabilize the power input voltage, and is the biggest problem. Specifically, in order to reduce the on-state power consumption of the MOS transistor, the MOS transistor is generally turned on in saturation. The driving voltage of the grid electrode of the MOS tube is normally 12V-15V, so that the input voltage DC is not too high or too low, the grid electrode of the MOS tube cannot obtain a high enough driving voltage due to too low input voltage, and the MOS tube cannot be saturated and has too large conduction loss; when the input voltage is too high, the voltage regulator tube D2 'is turned on, and the power loss on the voltage dividing resistor R1' is increased. Assuming D2 'is a 12V regulator, if the input voltage is 24V, then the power consumption of R1' is at least (24-12)2R1 '(ignoring losses due to MOS transistor drive current), R1' when the input voltage becomes 48VThe power consumption is at least (48-12)2The power consumption of the power amplifier is increased by 8 times when the input voltage is increased by one time, so that the power of the power amplifier is increased by geometric times when the input voltage is increased.
SUMMERY OF THE UTILITY MODEL
To this problem, the utility model provides a direct current input that power is stable prevents reverse connection protection circuit.
The purpose of the utility model is realized by the following technical scheme:
a direct current input reverse connection prevention protection circuit comprises: the power supply comprises a power supply, a DC-DC power conversion circuit, an auxiliary power supply and an MOS (metal oxide semiconductor) tube, wherein the positive end of the power supply is connected with the first input end of the DC-DC power conversion circuit, the input end of the auxiliary power supply is connected with the first output end of the DC-DC power conversion circuit, the output end of the auxiliary power supply is connected with the third end of the MOS tube through a sixteenth resistor, the second end of the MOS tube is connected with the second input end of the DC-DC power conversion circuit, the second end of the MOS tube is also connected with the third end of the MOS tube through a seventeenth resistor, and the first end of the MOS tube is connected with the negative end of the power supply.
Further, the MOS transistor is an NMOS, the first terminal of the MOS transistor is a drain terminal, the second terminal of the MOS transistor is a source terminal, and the third terminal of the MOS transistor is a gate terminal.
Further, the MOS transistor is a PMOS, the first terminal of the MOS transistor is a source terminal, the second terminal of the MOS transistor is a drain terminal, and the third terminal of the MOS transistor is a gate terminal.
Further, the auxiliary power supply comprises a third secondary winding of a transformer, a fifth diode and a seventh capacitor, the auxiliary power supply is connected with the DC-DC power conversion circuit through the transformer, one end of the third secondary winding of the transformer is connected with the negative end of the power supply, the other end of the third secondary winding of the transformer is connected with the positive end of the fifth diode, the negative end of the fifth diode is connected with one end of the seventh capacitor, the other end of the seventh capacitor is also connected with one end of the third secondary winding of the transformer, and the connection point of the fifth diode and the seventh capacitor is used as the output end of the auxiliary power supply.
Further, the DC-DC power conversion circuit includes a PWM control chip, the PWM control chip and a primary winding of a transformer form a switching loop, one end of the primary winding of the transformer is a first input end of the DC-DC power conversion circuit and is connected to a positive end of the power supply, and the other end of the primary winding of the transformer is connected to an output end of the PWM control chip.
Further, the DC-DC power conversion circuit further includes an absorption circuit, the absorption circuit includes a fifth resistor, a fifth capacitor, and a fourth diode, after the fifth resistor is connected in parallel with the fifth capacitor, one end of the fifth resistor is connected to the first input end of the DC-DC power conversion circuit, the other end of the fifth resistor is connected to the negative end of the fourth diode, and the positive end of the fourth diode is connected to the other end of the primary winding of the transformer.
Further, the DC-DC power conversion circuit further includes a voltage output circuit, the voltage output circuit includes a first secondary winding of the transformer, a first diode, and a second capacitor, one end of the first secondary winding of the transformer is connected to the positive end of the first diode, the other end of the first secondary winding of the transformer is grounded, the negative end of the first diode is used as the output end of the voltage output circuit, the negative end of the first diode is further connected to one end of the second capacitor, and the other end of the second capacitor is grounded.
Further, the DC-DC power conversion circuit further includes a working voltage providing circuit, the working voltage providing circuit includes a second secondary winding of a transformer, a second diode, a third capacitor, a fourth capacitor, and a fifteenth resistor, one end of the second secondary winding of the transformer is connected to the positive terminal of the second diode, the other end of the second secondary winding of the transformer is connected to the negative terminal of the power supply as the second input terminal of the DC-DC power conversion circuit, the negative terminal of the second diode is connected to one end of the third capacitor, the other end of the third capacitor is connected to the second input terminal of the DC-DC power conversion circuit, the negative terminal of the second diode is further connected to one end of the fifteenth resistor, and the other end of the fifteenth resistor is used as the output terminal of the working voltage providing circuit, and after the third diode is connected with the fourth capacitor in parallel, one end of the third diode is connected with the output end of the working voltage providing circuit, the other end of the third diode is connected with the second input end of the DC-DC power conversion circuit, the PWM control chip further comprises a fourth input end, and the output end of the working voltage providing circuit is connected with the fourth input end of the PWM control chip.
Further, the DC-DC power conversion circuit further includes a PWM oscillation signal circuit, the PWM oscillation signal circuit includes a sixth resistor, the PWM control chip further includes a fifth input terminal, one end of the sixth resistor is connected to the fifth input terminal of the PWM control chip, and the other end of the sixth resistor is connected to the second input terminal of the DC-DC power conversion circuit.
Further, the DC-DC power conversion circuit further includes a voltage stabilizing feedback network, the voltage stabilizing feedback network includes an optocoupler, a second three-terminal regulated power supply, a sixth capacitor, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, and a fourteenth resistor, an anode of a light emitting diode of the optocoupler is connected to an output terminal of the voltage output circuit through the twelfth resistor, an anode of the light emitting diode of the optocoupler is further connected to one end of the eleventh resistor, the other end of the eleventh resistor is connected to an input terminal of the second three-terminal regulated power supply, a ground terminal of the second three-terminal regulated power supply is grounded, a cathode of the light emitting diode of the optocoupler is also connected to the input terminal of the second three-terminal regulated power supply, and a collector of a phototriode of the optocoupler is connected to an output terminal of the working voltage supply circuit, an emitting electrode of a phototriode of the optocoupler is connected with one end of a ninth resistor, the other end of the ninth resistor is used as a first output end of the voltage-stabilizing feedback network, one end of an eighth resistor is connected with the other end of the ninth resistor, the other end of the eighth resistor is used as a second output end of the voltage-stabilizing feedback network, the emitting electrode of the phototriode of the optocoupler is further connected with a second input end of the DC-DC power conversion circuit through a seventh resistor, an output end of a second three-terminal type voltage-stabilizing power supply is connected with one end of a thirteenth resistor, the other end of a thirteenth resistor is connected with one end of a sixth capacitor, the other end of the sixth capacitor is also connected with an input end of the second three-terminal type voltage-stabilizing power supply, and an output end of the second three-terminal type voltage-stabilizing power supply is further connected with one end of a fourteenth resistor, the other end of the fourteenth resistor is connected with the output end of the voltage output circuit, the output end of the second three-terminal type voltage-stabilized power supply is further connected with one end of the tenth resistor, the other end of the tenth resistor is grounded, the PWM control chip further comprises a sixth input end and a seventh input end, the first output end of the voltage-stabilizing feedback network is connected with the sixth input end of the PWM control chip, and the second output end of the voltage-stabilizing feedback network is connected with the seventh input end of the PWM control chip.
Further, the DC-DC power conversion circuit further includes a power supply circuit, the power supply circuit includes a first three-terminal type voltage-stabilized power supply, a first resistor, a second resistor, a third resistor, a fourth resistor, the PWM control chip further includes a first input terminal, a second input terminal, and a third input terminal, the input terminal of the first three-terminal type voltage-stabilized power supply is connected to one terminal of the fourth resistor, the other terminal of the fourth resistor is connected to the first input terminal of the DC-DC power conversion circuit, the output terminal of the first three-terminal type voltage-stabilized power supply is short-circuited with the input terminal of the first three-terminal type voltage-stabilized power supply, the ground terminal of the first three-terminal type voltage-stabilized power supply is connected to the second input terminal of the DC-DC power conversion circuit and to the second input terminal of the PWM control chip, the input terminal of the first three-terminal type voltage-stabilized power supply is connected to the third input terminal of the PWM control chip through the third resistor, one end of the first resistor is connected with a first input end of the DC-DC power conversion circuit, the other end of the first resistor is connected with a second input end of the PWM control chip through the second resistor, a connection point of the first resistor and the second resistor is also connected with a third input end of the PWM control chip, and the first input end of the PWM control chip is connected with the first input end of the DC-DC power conversion circuit.
Further, the PWM control chip is MP6002 of MPS corporation, and has 8 pins, the first input end of the PWM control chip is pin 7 VIN, the second input end is pin 1 GND, the third input end is pin 2 LINE, the fourth input end is pin 6 VCC, the fifth input end is pin 5 RT, the sixth input end is pin 3 FB, the seventh input end is pin 4 COMP, and the output end is pin 8 SW.
Further, the DC-DC power conversion circuit further includes a first capacitor connected between the first input terminal and the second input terminal of the DC-DC power conversion circuit.
The utility model discloses use auxiliary power source to remove opening of control MOS pipe, and auxiliary power source derives from DC-DC power conversion circuit, and its output is in a stable within range, so the consumption of circuit can not increase along with input voltage's increase, and is corresponding, just can be at the reliable drive MOS pipe of wideer voltage range, but also can work with high efficiency. Furthermore, the utility model discloses utilize the one-way conductivity of MOS pipe to do and prevent reverse connection protection, make full use of MOS pipe saturation and turn on the characteristics that impedance is low, circuit overall efficiency is higher.
Drawings
Fig. 1 is a block diagram of a conventional reverse-connection protection circuit for dc input;
fig. 2 is a block diagram of another conventional reverse-connection protection circuit for dc input;
fig. 3 is a block diagram of a dc input reverse connection prevention protection circuit according to an embodiment of the present invention;
fig. 4 is a block diagram of a dc input reverse connection prevention protection circuit according to another embodiment of the present invention;
fig. 5 is a schematic circuit diagram of a dc input reverse connection prevention protection circuit according to an embodiment of the present invention.
Detailed Description
In order to make the above objects, features and advantages of the present invention more comprehensible, embodiments of the present invention are described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, as those skilled in the art will be able to make similar modifications without departing from the spirit and scope of the present invention.
It will be understood that when an element is referred to as being "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only and do not represent the only embodiments.
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 in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.
Referring to fig. 2, an embodiment of the present invention provides a dc input reverse connection prevention protection circuit, where the dc input reverse connection prevention protection circuit includes: the power supply J1, the DC-DC power conversion circuit (not numbered), the auxiliary power supply (not numbered) and the MOS tube Q1, wherein the positive end DC + of the power supply J1 is connected with the first input end of the DC-DC power conversion circuit, the input end of the auxiliary power supply is connected with the first output end of the DC-DC power conversion circuit, the output end of the auxiliary power supply is connected with the third end of the MOS tube Q1 through a sixteenth resistor R16, the second end of the MOS tube Q1 is connected with the second input end of the DC-DC power conversion circuit, the second end of the MOS tube Q1 is also connected with the third end of the MOS tube Q1 through a seventeenth resistor R17, and the first end of the MOS tube Q1 is connected with the negative end DC-of the power supply J1.
In this embodiment, the MOS transistor Q1 is an NMOS, the first terminal of the MOS transistor Q1 is a drain terminal D, the second terminal of the MOS transistor Q1 is a source terminal S, and the third terminal of the MOS transistor Q1 is a gate terminal G.
Referring to fig. 4, in another embodiment, the MOS transistor Q1 is a PMOS, the first terminal of the MOS transistor Q1 is a source terminal S, the second terminal of the MOS transistor is a drain terminal D, and the third terminal of the MOS transistor is a gate terminal G.
The working principle of the direct current input reverse connection prevention protection circuit shown in fig. 3 is as follows:
(1) when the positive terminal DC + and the negative terminal DC-on the power supply J1 are correctly connected into the circuit, the input direct current charge flows back to the negative terminal DC-from the positive terminal DC + through the auxiliary power supply internal circuit and the parasitic diode of the MOS tube Q1 to form a loop, and the voltage drop of the power-on instantaneous MOS tube Q1 is the forward voltage drop voltage of the parasitic diode;
(2) after a loop is formed between a positive end DC + and a negative end DC-of a power supply J1, an auxiliary power supply is electrified to start working and supply power to a related control circuit, the output end of the auxiliary power supply supplies power to a grid end G of an MOS tube Q1 to drive the MOS tube Q1 to be in saturated conduction, the voltage drop of the MOS tube Q1 is the product of a current I flowing between a drain end D and a source end S and a resistor RDSon when the MOS tube Q1 is in saturated conduction, and the voltage drop is far smaller than the forward conduction voltage drop of a parasitic diode;
(3) when the positive terminal DC + and the negative terminal of the power supply J1 are connected with the reverse access circuit, the parasitic diode of the MOS tube Q1 is reversely biased and cut off, the charges cannot flow back to the negative terminal DC-from the positive terminal DC + through the MOS tube Q1 to form a loop to supply power to the auxiliary power supply, the auxiliary power supply cannot be powered on to work, the related control circuit cannot be powered on to work, and the whole circuit cannot work.
Referring to fig. 5, the auxiliary power source includes a third secondary winding T1-C of a transformer T1, a fifth diode D5, and a seventh capacitor C7, the auxiliary power source is connected to the DC-DC power conversion circuit through the transformer T1, one end of the third secondary winding T1-C of the transformer T1 is DC-connected to the negative terminal of the power source J1, the other end of the third secondary winding T1-C is connected to the positive terminal of the fifth diode D5, the negative terminal of the fifth diode D5 is connected to one end of the seventh capacitor C7, the other end of the seventh capacitor C7 is also connected to one end of the third secondary winding T1-C of the transformer T1, and the connection point of the fifth diode D5 and the seventh capacitor C7 serves as the output terminal of the auxiliary power source.
The DC-DC power conversion circuit comprises a PWM control chip U1, the PWM control chip U1 and a primary winding T1-A of a transformer T1 form a switch loop, one end of the primary winding T1-A of the transformer T1 is connected with a positive end DC + of the power supply J1 as a first input end of the DC-DC power conversion circuit, and the other end of the primary winding T1-A of the transformer T1 is connected with an output end of the PWM control chip U1.
The DC-DC power conversion circuit further comprises an absorption circuit, the absorption circuit comprises a fifth resistor R5, a fifth capacitor C5 and a fourth diode D4, after the fifth resistor R5 and the fifth capacitor C5 are connected in parallel, one end of the fifth resistor R5 is connected with the first input end of the DC-DC power conversion circuit, the other end of the fifth resistor R5 is connected with the negative end of the fourth diode D4, and the positive end of the fourth diode D4 is connected with the other end of the primary winding T1-A of the transformer T1.
The DC-DC power conversion circuit further comprises a voltage output circuit, wherein the voltage output circuit comprises a first secondary winding T1-B of a transformer T1, a first diode D1 and a second capacitor C2, one end of the first secondary winding T1-B of the transformer T1 is connected with the positive end of a first diode D1, the other end of the first secondary winding T1-B of the transformer T1 is grounded, the negative end of a first diode D1 is used as the output end VOUT of the voltage output circuit, the negative end of the first diode D1 is further connected with one end of a second capacitor C2, and the other end of the second capacitor C2 is grounded.
The DC-DC power conversion circuit further comprises an operating voltage providing circuit, the operating voltage providing circuit comprises a second secondary winding T1-D of a transformer T1, a second diode D2, a third diode D3, a third capacitor C3, a fourth capacitor C4 and a fifteenth resistor R15, one end of a second secondary winding T1-B of the transformer T1 is connected with the positive end of the second diode D2, the other end of the second secondary winding T1-B of the transformer T1 is used as a second input end of the DC-DC power conversion circuit and is DC-connected with the negative end of the power supply J1, the negative end of the second diode D2 is connected with one end of the third capacitor C3, the other end of the third capacitor C3 is connected with the second input end of the DC-DC power conversion circuit, the negative end of the second diode D2 is further connected with one end of the fifteenth resistor R15, the other end of the fifteenth resistor R15 is used as the output VCC of the working voltage supply circuit, the third diode D3 is connected in parallel with the fourth capacitor C4, one end of the third diode is connected to the output VCC of the working voltage supply circuit, the other end of the third diode is connected to the second input end of the DC-DC power conversion circuit, the PWM control chip U1 further includes a fourth input end, and the output VCC of the working voltage supply circuit is connected to the fourth input end of the PWM control chip U1. Wherein the third diode D3 is a zener diode or a zener diode.
The DC-DC power conversion circuit further comprises a PWM oscillating signal circuit, the PWM oscillating signal circuit comprises a sixth resistor R6, the PWM control chip U1 further comprises a fifth input end, one end of the sixth resistor R6 is connected with the fifth input end of the PWM control chip U1, and the other end of the sixth resistor R6 is connected with the second input end of the DC-DC power conversion circuit.
The DC-DC power conversion circuit further includes a regulated feedback network, the regulated feedback network includes an optical coupler U4, a second three-terminal regulated power supply U3, a sixth capacitor C6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13, and a fourteenth resistor R14, an anode of a light emitting diode of the optical coupler U4 is connected to the output terminal VOUT of the voltage output circuit through the twelfth resistor R12, an anode of a light emitting diode of the optical coupler U4 is further connected to one end of the eleventh resistor R11, another end of the eleventh resistor R11 is connected to the input terminal of the second three-terminal regulated power supply U3, a ground terminal of the second three-terminal regulated power supply U3 is connected to ground, a cathode of the light emitting diode of the optical coupler U4 is also connected to the input terminal of the second three-terminal regulated power supply U3, a collector of a phototransistor of the optocoupler U4 is connected to an output VCC of the operating voltage supply circuit, an emitter of the phototransistor of the optocoupler U4 is connected to one end of a ninth resistor R9, the other end of the ninth resistor R9 is used as a first output end of the regulated feedback network, one end of an eighth resistor R8 is connected to the other end of the ninth resistor R9, the other end of an eighth resistor R8 is used as a second output end of the regulated feedback network, the emitter of the phototransistor of the optocoupler U4 is further connected to a second input end of the DC-DC power conversion circuit through a seventh resistor R7, an output end of a second three-terminal regulated power supply U3 is connected to one end of a thirteenth resistor R13, the other end of the thirteenth resistor R13 is connected to one end of a sixth capacitor C6, and the other end of the sixth capacitor C6 is also connected to an input end of the second three-terminal regulated power supply U3, the output end of the second three-terminal type regulated power supply U3 is further connected to one end of a fourteenth resistor R14, the other end of the fourteenth resistor R14 is connected to the output end VOUT of the voltage output circuit, the output end of the second three-terminal type regulated power supply U3 is further connected to one end of a tenth resistor R10, the other end of the tenth resistor R10 is grounded, the PWM control chip U1 further includes a sixth input end and a seventh input end, the first output end of the voltage stabilization feedback network is connected to the sixth input end of the PWM control chip U1, and the second output end of the voltage stabilization feedback network is connected to the seventh input end of the PWM control chip U1.
The DC-DC power conversion circuit further includes a power supply circuit, the power supply circuit includes a first three-terminal regulated power supply U2, a first resistor R1, a second resistor R2, a third resistor R3, and a fourth resistor R4, the PWM control chip U1 further includes a first input terminal, a second input terminal, and a third input terminal, an input terminal of the first three-terminal regulated power supply U2 is connected to one terminal of the fourth resistor R4, the other terminal of the fourth resistor R4 is connected to the first input terminal of the DC-DC power conversion circuit, an output terminal of the first three-terminal regulated power supply U2 is shorted to an input terminal of the first three-terminal regulated power supply U2, a ground terminal of the first three-terminal regulated power supply U2 is connected to the second input terminal of the DC-DC power conversion circuit and to the second input terminal of the PWM control chip U1, and an input terminal of the first three-terminal regulated power supply U2 is connected to the third input terminal regulated power supply U35 1 through the third resistor R3 The first resistor R1 has one end connected to the first input end of the DC-DC power conversion circuit, the other end connected to the second input end of the PWM control chip U1 through the second resistor R2, the connection point of the first resistor R1 and the second resistor R2 is also connected to the third input end of the PWM control chip U1, and the first input end of the PWM control chip U1 is connected to the first input end of the DC-DC power conversion circuit.
In this embodiment, the PWM control chip U1 is MP6002 of MPS corporation, and has 8 pins, the first input terminal of the PWM control chip U1 is pin 7 VIN, the second input terminal is pin 1 GND, the third input terminal is pin 2 LINE, the fourth input terminal is pin 6 VCC, the fifth input terminal is pin 5 RT, the sixth input terminal is pin 3 FB, the seventh input terminal is pin 4 COMP, and the output terminal is pin 8 SW.
The DC-DC power conversion circuit further comprises a first capacitor C1, and the first capacitor C1 is connected between the first input end and the second input end of the DC-DC power conversion circuit.
The utility model discloses use auxiliary power source to remove opening of control MOS pipe, and auxiliary power source derives from DC-DC power conversion circuit, and its output is in a stable within range, so the consumption of circuit can not increase along with input voltage's increase, and is corresponding, just can be at the reliable drive MOS pipe of wideer voltage range, but also can work with high efficiency. Furthermore, the utility model discloses utilize the one-way conductivity of MOS pipe to do and prevent reverse connection protection, make full use of MOS pipe saturation and turn on the characteristics that impedance is low, circuit overall efficiency is higher.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only represent some embodiments of the present invention, and the description thereof is specific and detailed, but not to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, without departing from the spirit of the present invention, several variations and modifications can be made, which are within the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.
Claims (13)
1. A direct current input reverse connection prevention protection circuit is characterized by comprising: the power supply comprises a power supply, a DC-DC power conversion circuit, an auxiliary power supply and an MOS (metal oxide semiconductor) tube, wherein the positive end of the power supply is connected with the first input end of the DC-DC power conversion circuit, the input end of the auxiliary power supply is connected with the first output end of the DC-DC power conversion circuit, the output end of the auxiliary power supply is connected with the third end of the MOS tube through a sixteenth resistor, the second end of the MOS tube is connected with the second input end of the DC-DC power conversion circuit, the second end of the MOS tube is also connected with the third end of the MOS tube through a seventeenth resistor, and the first end of the MOS tube is connected with the negative end of the power supply.
2. The direct current input reverse connection prevention protection circuit according to claim 1, wherein the MOS transistor is an NMOS, the first terminal of the MOS transistor is a drain terminal, the second terminal of the MOS transistor is a source terminal, and the third terminal of the MOS transistor is a gate terminal.
3. The direct current input reverse connection prevention protection circuit according to claim 1, wherein the MOS transistor is a PMOS, the first end of the MOS transistor is a source end, the second end of the MOS transistor is a drain end, and the third end of the MOS transistor is a gate end.
4. The direct current input reverse connection prevention protection circuit according to claim 1, wherein the auxiliary power supply comprises a third secondary winding of a transformer, a fifth diode and a seventh capacitor, the auxiliary power supply is connected with the DC-DC power conversion circuit through the transformer, one end of the third secondary winding of the transformer is connected with a negative end of the power supply, the other end of the third secondary winding of the transformer is connected with a positive end of the fifth diode, a negative end of the fifth diode is connected with one end of the seventh capacitor, the other end of the seventh capacitor is also connected with one end of the third secondary winding of the transformer, and a connection point of the fifth diode and the seventh capacitor serves as an output end of the auxiliary power supply.
5. The direct current input reverse connection prevention protection circuit according to claim 4, wherein the DC-DC power conversion circuit comprises a PWM control chip, the PWM control chip and a primary winding of a transformer form a switch loop, one end of the primary winding of the transformer is connected with a first input end of the DC-DC power conversion circuit and a positive end of the power supply, and the other end of the primary winding of the transformer is connected with an output end of the PWM control chip.
6. The direct current input reverse connection prevention protection circuit according to claim 5, wherein the DC-DC power conversion circuit further comprises an absorption circuit, the absorption circuit comprises a fifth resistor, a fifth capacitor and a fourth diode, after the fifth resistor and the fifth capacitor are connected in parallel, one end of the fifth resistor is connected with the first input end of the DC-DC power conversion circuit, the other end of the fifth resistor is connected with the negative end of the fourth diode, and the positive end of the fourth diode is connected with the other end of the primary winding of the transformer.
7. The DC input protection circuit of claim 6, wherein the DC-DC power conversion circuit further comprises a voltage output circuit, the voltage output circuit comprises a first secondary winding of a transformer, a first diode, and a second capacitor, one end of the first secondary winding of the transformer is connected to the positive terminal of the first diode, the other end of the first secondary winding of the transformer is grounded, the negative terminal of the first diode is used as the output terminal of the voltage output circuit, the negative terminal of the first diode is further connected to one end of the second capacitor, and the other end of the second capacitor is grounded.
8. The direct current input reverse connection prevention protection circuit according to claim 7, wherein the DC-DC power conversion circuit further comprises a working voltage providing circuit, the working voltage providing circuit comprises a second secondary winding of a transformer, a second diode, a third capacitor, a fourth capacitor and a fifteenth resistor, one end of the second secondary winding of the transformer is connected with a positive end of the second diode, the other end of the second secondary winding of the transformer is connected with a negative end of the power supply as a second input end of the DC-DC power conversion circuit, a negative end of the second diode is connected with one end of the third capacitor, the other end of the third capacitor is connected with a second input end of the DC-DC power conversion circuit, and a negative end of the second diode is further connected with one end of the fifteenth resistor, the other end of the fifteenth resistor is used as the output end of the working voltage providing circuit, after the third diode is connected with the fourth capacitor in parallel, one end of the third diode is connected with the output end of the working voltage providing circuit, the other end of the third diode is connected with the second input end of the DC-DC power conversion circuit, the PWM control chip further comprises a fourth input end, and the output end of the working voltage providing circuit is connected with the fourth input end of the PWM control chip.
9. The direct current input reverse connection prevention protection circuit according to claim 8, wherein the DC-DC power conversion circuit further comprises a PWM oscillating signal circuit, the PWM oscillating signal circuit comprises a sixth resistor, the PWM control chip further comprises a fifth input terminal, one end of the sixth resistor is connected to the fifth input terminal of the PWM control chip, and the other end of the sixth resistor is connected to the second input terminal of the DC-DC power conversion circuit.
10. The direct current input reverse connection prevention protection circuit according to claim 9, wherein the DC-DC power conversion circuit further comprises a voltage stabilization feedback network, the voltage stabilization feedback network comprises an optical coupler, a second three-terminal regulated power supply, a sixth capacitor, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, and a fourteenth resistor, an anode of a light emitting diode of the optical coupler is connected to the output terminal of the voltage output circuit through the twelfth resistor, an anode of a light emitting diode of the optical coupler is further connected to one end of the eleventh resistor, the other end of the eleventh resistor is connected to the input terminal of the second three-terminal regulated power supply, a ground terminal of the second three-terminal regulated power supply is grounded, and a cathode of the light emitting diode of the optical coupler is also connected to the input terminal of the second three-terminal regulated power supply, a collector of a phototriode of the optocoupler is connected with an output end of the working voltage supply circuit, an emitter of the phototriode of the optocoupler is connected with one end of a ninth resistor, the other end of the ninth resistor is used as a first output end of the voltage stabilization feedback network, one end of an eighth resistor is connected with the other end of the ninth resistor, the other end of the eighth resistor is used as a second output end of the voltage stabilization feedback network, the emitter of the phototriode of the optocoupler is further connected with a second input end of the DC-DC power conversion circuit through a seventh resistor, an output end of a second three-end type voltage stabilization power supply is connected with one end of a thirteenth resistor, the other end of the thirteenth resistor is connected with one end of a sixth capacitor, and the other end of the sixth capacitor is also connected with an input end of the second three-end type voltage stabilization power supply, the output end of the second three-terminal type voltage-stabilized power supply is further connected with one end of a fourteenth resistor, the other end of the fourteenth resistor is connected with the output end of the voltage output circuit, the output end of the second three-terminal type voltage-stabilized power supply is further connected with one end of a tenth resistor, the other end of the tenth resistor is grounded, the PWM control chip further comprises a sixth input end and a seventh input end, the first output end of the voltage-stabilizing feedback network is connected with the sixth input end of the PWM control chip, and the second output end of the voltage-stabilizing feedback network is connected with the seventh input end of the PWM control chip.
11. The direct current input reverse connection prevention protection circuit according to claim 10, wherein the DC-DC power conversion circuit further comprises a power supply circuit, the power supply circuit comprises a first three-terminal regulated power supply, a first resistor, a second resistor, a third resistor, a fourth resistor, the PWM control chip further comprises a first input terminal, a second input terminal, and a third input terminal, the input terminal of the first three-terminal regulated power supply is connected to one terminal of the fourth resistor, the other terminal of the fourth resistor is connected to the first input terminal of the DC-DC power conversion circuit, the output terminal of the first three-terminal regulated power supply is shorted to the input terminal of the first three-terminal regulated power supply, the ground terminal of the first three-terminal regulated power supply is connected to the second input terminal of the DC-DC power conversion circuit and to the second input terminal of the PWM control chip, the input end of the first three-terminal type voltage-stabilized power supply is connected with the third input end of the PWM control chip through the third resistor, one end of the first resistor is connected with the first input end of the DC-DC power conversion circuit, the other end of the first resistor is connected with the second input end of the PWM control chip through the second resistor, the connection point of the first resistor and the second resistor is also connected with the third input end of the PWM control chip, and the first input end of the PWM control chip is connected with the first input end of the DC-DC power conversion circuit.
12. The dc input reverse connection prevention protection circuit of claim 11, wherein the PWM control chip is MP6002 of MPS corporation, and has 8 pins, the first input terminal of the PWM control chip is pin 7 VIN, the second input terminal is pin 1 GND, the third input terminal is pin 2 LINE, the fourth input terminal is pin 6 VCC, the fifth input terminal is pin 5 RT, the sixth input terminal is pin 3 FB, the seventh input terminal is pin 4 COMP, and the output terminal is pin 8 SW.
13. The direct current input reverse connection protection circuit according to claim 11, wherein the DC-DC power conversion circuit further comprises a first capacitor connected between the first input terminal and the second input terminal of the DC-DC power conversion circuit.
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| CN201921307533.9U CN210404738U (en) | 2019-08-13 | 2019-08-13 | Reverse connection prevention protection circuit for direct current input |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN110445117A (en) * | 2019-08-13 | 2019-11-12 | 苏州格远电气有限公司 | Direct current inputs reverse connection prevention protection circuit |
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| CN110445117A (en) * | 2019-08-13 | 2019-11-12 | 苏州格远电气有限公司 | Direct current inputs reverse connection prevention protection circuit |
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