An anti-backflow circuit with input overvoltage protection

Abstract

The present invention discloses a novel backflow prevention circuit with input overvoltage protection, comprising a PV input unit, wherein the PV input unit is electrically connected to a PV input overvoltage detection unit, which is electrically connected to a controlled unit, and is also electrically connected to a P-channel MOS switch tube unit, which is electrically connected to a controlled unit, which is also electrically connected to a current sampling unit, which is also electrically connected to a main control chip unit, and the P-channel MOS switch tube unit is also electrically connected to a topology circuit. The present invention implements the backflow prevention function through the P-channel MOS switch tube unit, without the need to add an isolation drive circuit and an isolation auxiliary power supply, thereby simplifying the design of the backflow prevention circuit, and mainly implements the input overvoltage protection function and the input reverse connection prevention function through the PV input overvoltage detection unit, the controlled unit, and the P-channel MOS switch tube unit, making the product more competitive in the market.

Description

Technical Field

[0001] The present invention relates to the field of electronic technology, and in particular to a novel anti-backflow circuit with input overvoltage protection. Background Art

[0002] like Figure 1 As shown in the figure, the existing backflow prevention circuit uses an N-channel MOS transistor to implement the backflow prevention circuit, requiring the addition of an isolation drive circuit and an isolated auxiliary power supply. The isolated auxiliary power supply provides power to the isolation drive circuit, which in turn drives the N-channel MOS transistor for backflow prevention. The main control chip is responsible for providing primary-side drive to the isolation drive circuit and detecting current direction.

[0003] Initially, the PV is connected, and the PV provides power to the subsequent topology through the parasitic diode of the N-channel MOS tube. The main control chip turns on the N-channel MOS tube when it detects that the current is in the forward direction through the current sampling resistor. When the PV input terminal is not connected to the PV or is connected to a load, the main control chip turns off the N-channel MOS tube when it detects that the current is zero or in the reverse direction through the current sampling resistor, thereby achieving the anti-backflow effect.

[0004] The existing backflow prevention circuit uses an N-channel MOS tube to implement the backflow prevention circuit, which requires the addition of an isolation drive circuit and an isolation auxiliary power supply, making the entire backflow prevention circuit design more complicated, not conducive to adding functional applications to the product, and making the product's market competitiveness insufficient.

[0005] To this end, the present invention provides a novel anti-backflow circuit with input overvoltage protection. Summary of the Invention

[0006] In view of the above problems existing in the prior art, the object of the present invention is to provide an anti-backflow circuit with a simple design and multifunctional applications such as: anti-backflow function, overvoltage protection function and anti-reverse connection function.

[0007] The purpose of the present invention can be achieved through the following technical solutions:

[0008] A novel backflow prevention circuit with input overvoltage protection includes a PV input unit, which is electrically connected to a PV input overvoltage detection unit, which is electrically connected to a controlled unit. The PV input unit is also electrically connected to a P-channel MOS switch tube unit, which is electrically connected to the controlled unit. The controlled unit is also electrically connected to a current sampling unit, which is also electrically connected to a main control chip unit. The P-channel MOS switch tube unit is also electrically connected to a topology circuit.

[0009] As a further preferred technical solution of the present invention, the P-channel MOS switch tube unit is provided with a P-channel MOS tube M1, the S end point of the P-channel MOS tube M1 is electrically connected to the S end point of the P-channel MOS tube M2, the S end point of the P-channel MOS tube M1 is also electrically connected to the voltage regulator tube DZ2, the other end of the voltage regulator tube DZ2 is electrically connected to the G end point of the P-channel MOS tube M1, the S end point of the P-channel MOS tube M2 is also electrically connected to the current limiting resistor R5, and the other end of the current limiting resistor R5 is electrically connected to the G end point of the P-channel MOS tube M2.

[0010] As a further preferred technical solution of the present invention, the PV input unit is provided with two access points, PV+ and PV-, for accessing PV.

[0011] As a further preferred technical solution of the present invention, the controlled unit is provided with a transistor Q2, the collector of the transistor Q2 is electrically connected to the current-limiting resistor R6, the base of the transistor Q2 is electrically connected to the current-limiting resistors R3~4, the base of the transistor Q2 is also electrically connected to the collector of the transistor Q1, the base of the transistor Q1 is electrically connected to the current-limiting resistors R1~2, the other end of the current-limiting resistor R1 is electrically connected to the diode D2, the other end of the diode D2 is connected to the I / O terminal, and the emitter of the transistor Q2, the other end of the current-limiting resistor R2, and the other end of the current-limiting resistor R4 are electrically connected in parallel to the emitter of the transistor Q1.

[0012] As a further preferred technical solution of the present invention, the current sampling unit is composed of a sampling resistor RS1 electrically connected to the main control chip unit, the sampling resistor RS1 is also electrically connected to BAT-, and one end of the main control chip unit outputs an I / O endpoint.

[0013] As a further preferred technical solution of the present invention, the PV input overvoltage detection unit is provided with a voltage regulator tube DZ1 , and the voltage regulator tube DZ1 is electrically connected to the diode D1 .

[0014] As a further preferred technical solution of the present invention, the other end of the topology circuit is electrically connected to BAT+.

[0015] As described above, the novel anti-backflow circuit with input overvoltage protection provided by the present invention has the following beneficial effects:

[0016] 1. The present invention utilizes the aforementioned novel backflow prevention circuit with input overvoltage protection. Compared with the prior art, the backflow prevention function of the novel backflow prevention circuit with input overvoltage protection adopts the following circuit structure: two pairs of P-channel MOS transistors are provided to realize the backflow prevention function, abandoning the traditional design scheme of using N-channel MOS transistors, isolated drive circuits and isolated auxiliary power supplies as the backflow prevention circuit, simplifying the backflow prevention circuit design and leaving ample room for adding functional applications to the product.

[0017] 2. The present invention utilizes the aforementioned novel backflow prevention circuit with input overvoltage protection. Compared with the prior art, the overvoltage protection function of the novel backflow prevention circuit with input overvoltage protection adopts the following circuit structure: a voltage regulator diode DZ1 is provided. When the voltage is too high, the voltage regulator diode DZ1 reversely breaks down, thereby turning off the P-channel MOS transistors M1 and M2, thereby protecting the novel backflow prevention circuit with input overvoltage protection from being damaged by the high voltage.

[0018] 3. The present invention utilizes the aforementioned novel anti-backflow circuit with input overvoltage protection. Compared with the prior art, the anti-reverse connection function of the novel anti-backflow circuit with input overvoltage protection adopts the following circuit structure: a diode D1 is provided. The unidirectional blocking property of the diode D1 and the parasitic diodes of the P-channel MOS transistors M1 and M2 cuts off the P-channel MOS transistors M1 and M2, so that the main circuit has the anti-reverse connection function. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 The figure is a circuit schematic diagram of an existing anti-backflow circuit.

[0021] Figure 2 This is a circuit functional module framework diagram of an embodiment of a novel anti-backflow circuit with input overvoltage protection of the present invention.

[0022] Figure 3 The following is a schematic diagram of the circuit structure of an embodiment of a novel anti-backflow circuit with input overvoltage protection according to the present invention.

[0023] In the figure: 1. PV input unit; 2. P-channel MOS switch tube unit; 3. PV input overvoltage detection unit; 4. Main control chip unit; 5. Controlled unit; 6. Current sampling unit. DETAILED DESCRIPTION

[0024] The following describes the implementation of the present invention through specific embodiments. People skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0025] It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention. Therefore, they have no technical substantive significance. Any modification of the structure, change in the proportional relationship, or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the efficacy and purpose that can be achieved by the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description and are not used to limit the scope of the implementation of the present invention. Changes or adjustments in their relative relationships should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content. The specific structure can be described with reference to the drawings of the patent application.

[0026] The present invention provides a new type of anti-backflow circuit with input overvoltage protection, please refer to Figures 2 to 3 As shown, it includes a PV input unit 1, which is electrically connected to a PV input overvoltage detection unit 3, which is electrically connected to a controlled unit 5. The PV input unit 1 is also electrically connected to a P-channel MOS switch tube unit 2, which is electrically connected to a controlled unit 5. The controlled unit 5 is also electrically connected to a current sampling unit 6, which is also electrically connected to a main control chip unit 4. The P-channel MOS switch tube unit 2 is also electrically connected to a topology circuit, and the other end of the topology circuit is electrically connected to BAT+.

[0027] The P-channel MOS switch tube unit 2 is provided with a P-channel MOS tube M1. The S end point of the P-channel MOS tube M1 is electrically connected to the S end point of the P-channel MOS tube M2. The S end point of the P-channel MOS tube M1 is also electrically connected to the voltage regulator tube DZ2. The other end of the voltage regulator tube DZ2 is electrically connected to the G end point of the P-channel MOS tube M1. The S end point of the P-channel MOS tube M2 is also electrically connected to the current limiting resistor R5. The other end of the current limiting resistor R5 is electrically connected to the G end point of the P-channel MOS tube M2. The D end point of the P-channel MOS tube M1 is electrically connected to the PV input unit 1. The PV input unit 1 is provided with two access points, PV+ and PV-, for accessing the PV.

[0028] The PV input unit 1 is also electrically connected to the controlled unit 5. The controlled unit 5 is provided with a transistor Q2. The collector of the transistor Q2 is electrically connected to the current-limiting resistor R6. The base of the transistor Q2 is electrically connected to the current-limiting resistors R3-4. The base of the transistor Q2 is also electrically connected to the collector of the transistor Q1. The base of the transistor Q1 is electrically connected to the current-limiting resistors R1-2. The other end of the current-limiting resistor R1 is electrically connected to the diode D2. The other end of the diode D2 is connected to the I / O terminal. The emitter of the transistor Q2 and the current-limiting resistor R 2, the other end of the current-limiting resistor R4 is electrically connected in parallel with the emitter of the transistor Q1, the controlled unit 5 is electrically connected to the current sampling unit 6, and the current sampling unit 6 is composed of a sampling resistor RS1 electrically connected to the main control chip unit 4. The sampling resistor RS1 is also electrically connected to BAT-. One end of the main control chip unit 4 outputs an I / O endpoint. The controlled unit 5 is also electrically connected to the PV input overvoltage detection unit 3. The PV input overvoltage detection unit 3 is provided with a voltage regulator DZ1, and the voltage regulator DZ1 is electrically connected to the diode D1.

[0029] Example 1: When a novel backflow prevention circuit with input overvoltage protection is connected to a PV, the PV turns on the transistor Q2 of the controlled unit 5 through the current limiting resistor R3 of the controlled unit 5. The conduction of the transistor Q2 causes the VGS of the P-channel MOS transistors M1 and M2 of the P-channel MOS switch unit 2 to reach the conduction voltage. The P-channel MOS transistors M and M2 are turned on to enable the subsequent power circuit to obtain electrical energy.

[0030] Example 2: When a new backflow prevention circuit with input overvoltage protection is not connected to PV, the transistor Q2 of the controlled unit 5 is not turned on, and BAT+ passes through the parasitic diode of the P-channel MOS tube M2 of the P-channel MOS switch tube unit 2 and the current-limiting resistor R5 of the controlled unit 5 to make the VGS of the P-channel MOS tubes M1 and M2 0, and the P-channel MOS tubes M1 and M2 are turned off, thereby achieving the backflow prevention effect.

[0031] Embodiment 3: In a novel backflow prevention circuit with input overvoltage protection, when the P-channel MOS transistors M1 and M2 of the P-channel MOS switch tube unit 2 are turned on and the input is connected to a load or the input is not connected to a PV, the main control chip unit 4 sets the I / O high by detecting the magnitude of the current fed back by the sampling resistor RS1 and the reverse direction of the current, so that the VBE of the transistor Q1 of the controlled unit 5 is greater than 0, the transistor Q1 is turned on, and the conduction of the transistor Q1 causes the VBE of the transistor Q2 of the controlled unit 5 to be 0, causing the transistor Q2 to be turned off, thereby causing the VGS of the P-channel MOS transistors M1 and M2 of the P-channel MOS switch tube unit 2 to be 0, and the P-channel MOS transistors M1 and M2 to be turned off, thereby achieving an anti-backflow effect.

[0032] Example 4: A novel backflow prevention circuit with input overvoltage protection. When the PV voltage input is too high, the excessive voltage causes the voltage regulator DZ1 of the PV input overvoltage detection unit 3 to reversely break down, turning on the transistor Q1 of the controlled unit 5. The conduction of the transistor Q1 causes the VBE of the transistor Q2 of the controlled unit 5 to be 0, and the transistor Q2 to be turned off, thereby causing the VGS of the P-channel MOS transistors M1 and M2 of the P-channel MOS switch unit 2 to be 0, and the P-channel MOS transistors M1 and M2 to be turned off, thereby achieving the input overvoltage protection function.

[0033] Example 5: When the PV input of a novel backflow prevention circuit with input overvoltage protection is reversely connected, the diode D1 of the PV input overvoltage detection unit 3 and the parasitic diodes of the P-channel MOS transistors M1 and M2 of the P-channel MOS switch tube unit 2 are unidirectionally cut off, so that the P-channel MOS transistors M1 and M2 are cut off, thereby achieving the anti-reverse connection function effect.

[0034] In summary, the overvoltage protection function of the novel backflow prevention circuit with input overvoltage protection of the present invention is mainly achieved by breaking down the voltage regulator tube due to excessive voltage, so that the P-channel MOS tubes M1 and M2 are turned off, thereby achieving the input overvoltage protection function effect;

[0035] The anti-reverse connection function of the novel anti-backflow circuit with input overvoltage protection of the present invention is achieved by cutting off the P-channel MOS tubes M1 and M2 through the unidirectional cutoff property of the diode, thereby achieving the anti-reverse connection function effect;

[0036] The present invention provides a new type of backflow prevention circuit with input overvoltage protection, which uses two pairs of P-channel MOS tubes to realize the circuit's backflow prevention function, abandoning the traditional design scheme of using N-channel MOS tubes, isolation drive circuits and isolated auxiliary power supplies as backflow prevention circuits, simplifying the backflow prevention circuit design and leaving ample room for adding functional applications to the product.

[0037] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be included therein. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

Claims

1. A backflow prevention circuit with input overvoltage protection, characterized in that: The PV input unit includes a PV input unit, the PV input unit is electrically connected to a PV input overvoltage detection unit, the PV input overvoltage detection unit is electrically connected to a controlled unit, the PV input unit is also electrically connected to a P-channel MOS switch tube unit, the P-channel MOS switch tube unit is electrically connected to the controlled unit, the controlled unit is also electrically connected to a current sampling unit, the current sampling unit is also electrically connected to a main control chip unit, and the P-channel MOS switch tube unit is also electrically connected to a topology circuit; The P-channel MOS switch tube unit is provided with a P-channel MOS tube M1. The S end point of the P-channel MOS tube M1 is electrically connected to the S end point of the P-channel MOS tube M2. The S end point of the P-channel MOS tube M1 is also electrically connected to the voltage regulator tube DZ2. The other end of the voltage regulator tube DZ2 is electrically connected to the G end point of the P-channel MOS tube M1. The S end point of the P-channel MOS tube M2 is also electrically connected to the current-limiting resistor R5. The other end of the current-limiting resistor R5 is electrically connected to the G end point of the P-channel MOS tube M2.

2. The anti-backflow circuit with input overvoltage protection according to claim 1, characterized in that: The PV input unit is provided with two access points, PV+ and PV-, for accessing PV.

3. The anti-backflow circuit with input overvoltage protection according to claim 2, characterized in that: The controlled unit is provided with a transistor Q2, the collector of the transistor Q2 is electrically connected to the current-limiting resistor R6, the base of the transistor Q2 is electrically connected to the current-limiting resistors R3 and R4, the base of the transistor Q2 is also electrically connected to the collector of the transistor Q1, the base of the transistor Q1 is electrically connected to the current-limiting resistors R1 and R2, the other end of the current-limiting resistor R1 is electrically connected to the diode D2, the other end of the diode D2 is connected to the I / O terminal, and the emitter of the transistor Q2, the other end of the current-limiting resistor R2, and the other end of the current-limiting resistor R4 are electrically connected in parallel to the emitter of the transistor Q1.

4. The anti-backflow circuit with input overvoltage protection according to claim 3, characterized in that: The current sampling unit is composed of a sampling resistor RS1 electrically connected to the main control chip unit. The sampling resistor RS1 is also electrically connected to BAT-. One end of the main control chip unit outputs an I / O terminal.

5. The anti-backflow circuit with input overvoltage protection according to claim 4, characterized in that: The PV input overvoltage detection unit is provided with a voltage regulator tube DZ1 , and the voltage regulator tube DZ1 is electrically connected to the diode D1 .

6. The anti-backflow circuit with input overvoltage protection according to claim 5, characterized in that: The other end of the topology circuit is electrically connected to BAT+.

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