An on-board 28V DC over-voltage surge suppression circuit and method

Abstract

The present application relates to a kind of airborne 28V direct current overvoltage surge suppression circuit and overvoltage surge suppression method.The circuit is composed of overvoltage detection circuit, drive circuit, switch circuit and voltage divider resistor, the input surge voltage is clamped within a certain range by the way of resistance voltage division in the present application, ensure that the load in the back stage works within the safe voltage.Overvoltage detection circuit detects whether there is overvoltage surge, when overvoltage surge occurs, control drive circuit operation, drive circuit drives switch circuit 2 to turn on, switch circuit 1 is closed, at this time, voltage divider resistor 1 and voltage divider resistor 2 are put into work, form resistance voltage division, clamp the output voltage within the safe voltage range.Compared with the mainstream technical scheme of existing MOS tube dissipation method, chopper method, etc., the 28V direct current overvoltage surge suppression circuit provided by the present application has the advantages of large power, high efficiency, simple circuit and device nationalization, etc.The present application is suitable for the scene that 28V direct current input and load output are not common.

Description

Technical Field

[0001] The present invention belongs to the technical field of power electronics, and in particular relates to an airborne 28V DC overvoltage surge suppression circuit and an overvoltage surge suppression method. Background Art

[0002] The 28V DC power supply is used on aircraft. When high-power loads are switched on or off, or when the load changes suddenly, the 28V DC power supply line can experience brief overvoltage spikes. According to the "GJB181 - Aircraft Power Supply Characteristics" standard, equipment using an onboard 28V DC power supply must withstand an 80V / 50ms overvoltage surge to prevent damage. An overvoltage surge suppression circuit absorbs, isolates, or limits overvoltage spikes to protect downstream loads.

[0003] Common overvoltage surge suppression methods include the following: The first is to connect an overvoltage absorption device such as a transient voltage suppression diode or varistor in parallel at the input end of the device. This has the advantage of a simple circuit, but the disadvantage is that it can only be used for situations where the overvoltage duration is relatively short. Once the overvoltage duration lasts for a long time, the device will be damaged by overheating. The second is to connect an electronic switch in series in the loop. When an overvoltage surge occurs, the electronic switch is disconnected, preventing the overvoltage surge from entering the downstream load. This has the advantage of a relatively simple circuit, but the disadvantage is that when the overvoltage surge occurs, the load has no power input and is in the off state, which is not suitable for loads with continuous operation requirements. The third is to connect a MOS transistor in series in the loop. When an overvoltage surge occurs, the MOS transistor operates in the linear region, and the MOS transistor bears the power consumption of the overvoltage part. This has the advantage of a wide range of applications, but the disadvantage is that it is limited by the power in the safe zone of the MOS transistor and is not suitable for high-power load scenarios. The fourth is to use a buck circuit. This has the advantage of very wide applicability, but the disadvantage is the circuit complexity, large size, and slightly low efficiency.

[0004] Due to the special requirements of high power, high efficiency, small size and localization, several commonly used overvoltage surge limiting circuits can no longer meet the needs of certain applications. Summary of the Invention

[0005] The purpose of the present invention is to provide an airborne 28V DC overvoltage surge suppression circuit and an overvoltage surge suppression method, which can meet application scenarios with high requirements on power, efficiency and volume, and the devices used can meet the requirements of complete localization.

[0006] The present invention provides an airborne 28V DC overvoltage surge suppression circuit, which includes an overvoltage detection circuit, a drive circuit, a switch circuit, and a voltage dividing resistor.

[0007] The overvoltage detection circuit has the function of detecting whether an overvoltage surge occurs in the input voltage and controlling the drive circuit.

[0008] The driving circuit has the function of controlling the switching circuit to be turned on and off.

[0009] The switch circuit has the function of controlling whether the voltage divider resistor is put into operation.

[0010] The voltage divider resistor has the function of clamping the output voltage.

[0011] Preferably, the overvoltage detection circuit includes a resistor R1, a resistor R2, a capacitor C1, and a voltage reference V1.

[0012] Among them, one end of resistor R1 is connected to the positive end of the 28V input, and the other end is connected to one end of resistor R2, one end of capacitor C1, and pin 3 of voltage reference V1; capacitor C1, resistor R2 and pin 1 of voltage reference V1 are connected to the negative end of the 28V input; pin 2 of voltage reference V1 is connected to pin 2 of optocoupler N2.

[0013] Preferably, the driving circuit includes a resistor R3, a resistor R4, a resistor R7, a resistor R8, a resistor R9, a resistor R13, an optocoupler N1, an optocoupler N2, a transistor Q1 and a transistor Q2.

[0014] Among them, one end of the resistor R3 is connected to the positive end of the 28V input, and the other end is connected to one end of the resistor R13 and pin 1 of the optocoupler N1; the other end of the resistor R13 is connected to the negative end of the 28V input; pin 2 of the optocoupler N1 is connected to pin 1 of the optocoupler N2; pin 2 of the optocoupler N2 is connected to pin 2 of the voltage reference V1; one end of the resistor R4 is connected to the positive end of the 28V input, and the other end is connected to pin 4 of the optocoupler N1; pin 3 of the optocoupler N1 is connected to pin 2 of the transistor Q1; pin 1 of the transistor Q1 is connected to the negative end of the 28V input; pin 3 of the transistor Q1 is connected to one end of the resistor R5 and the voltage regulator Pin 2 of D1, one end of capacitor C2, one end of resistor R6, and pin 2 of MOS tube D3 are connected; one end of resistor R7 is connected to the positive end of the 28V input, and the other end is connected to one end of resistor R8 and pin 4 of optocoupler N2; the other end of resistor R8 is connected to the negative end of the 28V output; one end of resistor R9 is connected to the positive end of the 28V input, and the other end is connected to pin 3 of transistor Q2; pin 2 of transistor Q2 is connected to pin 3 of optocoupler N2; pin 1 of transistor Q2 is connected to one end of resistor R10, pin 2 of voltage regulator D2, one end of capacitor C3, and pin 2 of MOS tube D4.

[0015] Preferably, the switch circuit 1 includes a resistor R5, a resistor R6, a capacitor C2, a voltage regulator tube D1 and a MOS tube D3.

[0016] Among them, one end of resistor R5 is connected to the positive end of the 28V input, and the other end is connected to one end of resistor R6, one end of capacitor C2, pin 2 of Zener diode D1, pin 3 of transistor Q1, and pin 2 of MOS transistor D3; pin 1 of Zener diode D1 is connected to the negative end of the 28V input; pin 1 of transistor Q, the other end of capacitor C2, the other end of resistor R6, and pin 3 of MOS transistor D3 are connected to the negative end of the 28V input; pin 1 of MOS transistor D3 is connected to the negative end of the 28V output.

[0017] Preferably, the switch circuit 2 includes a resistor R10, a capacitor C3, a voltage regulator tube D2 and a MOS tube D4.

[0018] Among them, pin 2 of MOS transistor D4 is connected to pin 1 of transistor Q2, one end of resistor R10, one end of capacitor C3, and pin 2 of voltage regulator D2; pin 1 of MOS transistor D4 is connected to one end of resistor R12; pin 3 of MOS transistor D4, pin 1 of voltage regulator D2, the other end of capacitor C3, and the other end of resistor R10 are connected to the negative terminal of the 28V output.

[0019] Preferably, the voltage-dividing resistor 1 includes a resistor R11 , and the voltage-dividing resistor 2 includes a resistor R12 .

[0020] Among them, one end of the resistor R11 is connected to the negative end of the 28V input, and the other end is connected to the negative end of the 28V output; one end of the resistor R12 is connected to the positive end of the 28V input, and the other end is connected to pin 1 of the MOS tube D4.

[0021] The present invention provides an airborne 28V DC overvoltage surge suppression method, which is implemented based on the above circuit. The method steps are as follows:

[0022] Step 1: When the 28V input is normal, the switch circuit 2 is in the off state, the switch circuit 1 is in the on state, and 28V is directly output.

[0023] Step 2: When an overvoltage surge occurs on the 28V input, the overvoltage detection circuit detects the overvoltage surge and controls the drive circuit to operate.

[0024] Step 3: The driving circuit drives the switch circuit, so that the switch circuit 2 is in the on state and the switch circuit 1 is in the off state. At this time, the output voltage is equal to the voltage on the voltage divider resistor 2.

[0025] Preferably, the resistance value of the voltage divider resistor is reasonably set so that the output voltage is within a reasonable voltage range.

[0026] The beneficial effects of the present invention are:

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. Since the present invention adopts the method of resistor voltage division, the load power that can be protected depends on the ability of the voltage divider resistor to withstand instantaneous power. Therefore, by selecting a suitable voltage divider resistor, the load power can be achieved to more than 2KW.

[0029] 2. The circuit structure of the present invention is simple and the devices used are all domestically produced devices. Therefore, the present invention has the characteristics of low cost and pure domestic production. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Principle block diagram of an airborne 28V DC overvoltage surge suppression circuit

[0031] Figure 2 Circuit diagram of an airborne 28V DC overvoltage surge suppression circuit

[0032] Figure 3 Equivalent circuit diagram of the circuit working state when there is no overvoltage surge

[0033] Figure 4 Equivalent circuit diagram of the circuit working state when there is an overvoltage surge DETAILED DESCRIPTION

[0034] The technical solutions provided by the present invention will be described in detail below with reference to specific embodiments. It should be understood that the following specific embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0035] The present invention provides an airborne 28V DC overvoltage surge suppression circuit. Figure 1 This is the principle block diagram of the circuit. The circuit consists of an overvoltage detection circuit, a drive circuit, a switching circuit and a voltage divider resistor. The present invention ultimately clamps the input surge voltage within a certain range through resistor voltage division, ensuring that the subsequent load operates within a safe voltage.

[0036] Overvoltage surge suppression circuit working process: When the 28V input is normal, the switch circuit 2 is in the off state, the switch circuit 1 is in the on state, and the 28V is directly output ( Figure 3 When an overvoltage surge occurs on the 28V input, the overvoltage detection circuit detects the overvoltage surge and controls the drive circuit to operate. The drive circuit drives the switch circuit, making switch circuit 2 in the on state and switch circuit 1 in the off state. At this time, the output voltage is equal to the voltage on the voltage divider resistor 2 ( Figure 4 ). According to the size of the load, the resistance of the voltage divider resistor can be reasonably set to make the output voltage within a reasonable voltage range.

[0037] Figure 2 This is an airborne 28V DC overvoltage surge suppression circuit diagram, which details the specific circuit.

[0038] The overvoltage detection circuit includes a resistor R1, a resistor R2, a capacitor C1, and a voltage reference V1.

[0039] Among them, one end of resistor R1 is connected to the positive end of the 28V input, and the other end is connected to one end of resistor R2, one end of capacitor C1, and pin 3 of voltage reference V1; capacitor C1, resistor R2 and pin 1 of voltage reference V1 are connected to the negative end of the 28V input; pin 2 of voltage reference V1 is connected to pin 2 of optocoupler N2.

[0040] When the voltage (Vin×R2 / (R1+R2)) at the filter voltage divider formed by resistors R1, R2 and capacitor C1 exceeds 2.5V, the voltage reference V1 drives the optocouplers N1 and N2 to operate.

[0041] The driving circuit includes a resistor R3, a resistor R4, a resistor R7, a resistor R8, a resistor R9, a resistor R13, an optocoupler N1, an optocoupler N2, a transistor Q1 and a transistor Q2.

[0042] Among them, one end of the resistor R3 is connected to the positive end of the 28V input, and the other end is connected to one end of the resistor R13 and pin 1 of the optocoupler N1; the other end of the resistor R13 is connected to the negative end of the 28V input; pin 2 of the optocoupler N1 is connected to pin 1 of the optocoupler N2; pin 2 of the optocoupler N2 is connected to pin 2 of the voltage reference V1; one end of the resistor R4 is connected to the positive end of the 28V input, and the other end is connected to pin 4 of the optocoupler N1; pin 3 of the optocoupler N1 is connected to pin 2 of the transistor Q1; pin 1 of the transistor Q1 is connected to the negative end of the 28V input; pin 3 of the transistor Q1 is connected to one end of the resistor R5 and the voltage regulator Pin 2 of D1, one end of capacitor C2, one end of resistor R6, and pin 2 of MOS tube D3 are connected; one end of resistor R7 is connected to the positive end of the 28V input, and the other end is connected to one end of resistor R8 and pin 4 of optocoupler N2; the other end of resistor R8 is connected to the negative end of the 28V output; one end of resistor R9 is connected to the positive end of the 28V input, and the other end is connected to pin 3 of transistor Q2; pin 2 of transistor Q2 is connected to pin 3 of optocoupler N2; pin 1 of transistor Q2 is connected to one end of resistor R10, pin 2 of voltage regulator D2, one end of capacitor C3, and pin 2 of MOS tube D4.

[0043] Among them, the voltage divider circuit composed of R3 and R13 ensures that the voltage reference V1 is not damaged when an overvoltage surge occurs; after the optocoupler N1 is turned on, the transistor Q1 is driven to be turned on and the MOS tube D3 is turned off; after the optocoupler N2 is turned on, the transistor Q2 is driven to be turned on and the MOS tube D4 is turned on.

[0044] The switch circuit 1 includes a resistor R5, a resistor R6, a capacitor C2, a voltage regulator D1 and a MOS transistor D3.

[0045] Among them, one end of resistor R5 is connected to the positive end of the 28V input, and the other end is connected to one end of resistor R6, one end of capacitor C2, pin 2 of Zener diode D1, pin 3 of transistor Q1, and pin 2 of MOS transistor D3; pin 1 of Zener diode D1 is connected to the negative end of the 28V input; pin 1 of transistor Q, the other end of capacitor C2, the other end of resistor R6, and pin 3 of MOS transistor D3 are connected to the negative end of the 28V input; pin 1 of MOS transistor D3 is connected to the negative end of the 28V output.

[0046] The voltage on the GS of the MOS tube D3 is obtained by dividing the voltage by resistors R5 and R6. The resistance value should be selected to meet Vin×R6 / (R5+R6)>12V to ensure that the MOS tube is reliably turned on. The function of the voltage regulator tube D1 is to limit the voltage on the GS of the MOS tube D3 to 12V to prevent the MOS tube from being damaged.

[0047] The switch circuit 2 includes a resistor R10, a capacitor C3, a voltage regulator D2 and a MOS transistor D4.

[0048] Among them, pin 2 of MOS transistor D4 is connected to pin 1 of transistor Q2, one end of resistor R10, one end of capacitor C3, and pin 2 of voltage regulator D2; pin 1 of MOS transistor D4 is connected to one end of resistor R12; pin 3 of MOS transistor D4, pin 1 of voltage regulator D2, the other end of capacitor C3, and the other end of resistor R10 are connected to the negative terminal of the 28V output.

[0049] The voltage on the GS of the MOS tube D4 is obtained by dividing it by resistors R9 and R10. The resistance value should be selected to meet Vout×R10 / (R9+R10)>12V to ensure that the MOS tube is reliably turned on. The function of the voltage regulator tube D2 is to limit the voltage on the GS of the MOS tube D4 to 12V to prevent damage to the MOS tube.

[0050] The voltage-dividing resistor 1 includes a resistor R11 , and the voltage-dividing resistor 2 includes a resistor R12 .

[0051] Among them, one end of the resistor R11 is connected to the negative end of the 28V input, and the other end is connected to the negative end of the 28V output; one end of the resistor R12 is connected to the positive end of the 28V input, and the other end is connected to pin 1 of the MOS tube D4.

[0052] Resistors R11 and R12 are high-power pulse-resistant resistors. When an overvoltage surge occurs, the output voltage Vout is related not only to these two resistors but also to the load impedance Rd, satisfying the expression Vout = Vin × [R12 × Rd / (R12 + Rd)] / [R11 + R12 × Rd / (R12 + Rd)].

[0053] The present invention provides an airborne 28V DC overvoltage surge suppression method, which is implemented based on the above circuit. The method steps are as follows:

[0054] Step 1: When the 28V input is normal, the switch circuit 2 is in the off state, the switch circuit 1 is in the on state, and 28V is directly output.

[0055] Step 2: When an overvoltage surge occurs on the 28V input, the overvoltage detection circuit detects the overvoltage surge and controls the drive circuit to operate.

[0056] Step 3: The driving circuit drives the switch circuit, so that the switch circuit 2 is in the on state and the switch circuit 1 is in the off state. At this time, the output voltage is equal to the voltage on the voltage divider resistor 2.

[0057] Preferably, the resistance value of the voltage divider resistor is reasonably set so that the output voltage is within a reasonable voltage range.

[0058] The above description is only the best specific implementation method of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or replacements that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention should be covered by the scope of protection of the present invention.

[0059] The contents not described in detail in the specification of the present invention belong to the common knowledge of professionals in this field.

Claims

1. An airborne 28V DC overvoltage surge suppression circuit, characterized in that: The circuit includes an overvoltage detection circuit, a driving circuit, a switching circuit and a voltage dividing resistor; The overvoltage detection circuit has the function of detecting whether the input voltage has an overvoltage surge and controlling the drive circuit; The driving circuit has the function of controlling the switching circuit to be turned on and off; The switch circuit has the function of controlling whether the voltage divider resistor is put into operation; The voltage divider resistor has the function of clamping the output voltage; The overvoltage detection circuit includes a resistor R1, a resistor R2, a capacitor C1, and a voltage reference V1; The driving circuit includes a resistor R3, a resistor R4, a resistor R7, a resistor R8, a resistor R9, a resistor R13, an optical coupler N1, an optical coupler N2, a transistor Q1 and a transistor Q2; The switch circuit 1 includes a resistor R5, a resistor R6, a capacitor C2, a voltage regulator tube D1 and a MOS tube D3; The switch circuit 2 includes a resistor R10, a capacitor C3, a voltage regulator tube D2 and a MOS tube D4; The voltage dividing resistor 1 includes a resistor R11, and the voltage dividing resistor 2 includes a resistor R12; One end of the resistor R1 is connected to the positive end of the 28V input, and the other end is connected to one end of the resistor R2, one end of the capacitor C1, and pin 3 of the voltage reference V1; the capacitor C1, the resistor R2, and pin 1 of the voltage reference V1 are connected to the negative end of the 28V input; pin 2 of the voltage reference V1 is connected to pin 2 of the optocoupler N2; One end of the resistor R3 is connected to the positive end of the 28V input, and the other end is connected to one end of the resistor R13 and pin 1 of the optocoupler N1; the other end of the resistor R13 is connected to the negative end of the 28V input; pin 2 of the optocoupler N1 is connected to pin 1 of the optocoupler N2; pin 2 of the optocoupler N2 is connected to pin 2 of the voltage reference V1; one end of the resistor R4 is connected to the positive end of the 28V input, and the other end is connected to pin 4 of the optocoupler N1; pin 3 of the optocoupler N1 is connected to pin 2 of the transistor Q1; pin 1 of the transistor Q1 is connected to the negative end of the 28V input; pin 3 of the transistor Q1 is connected to one end of the resistor R5 and the voltage regulator D Connect pin 2 of MOSFET 1, one end of capacitor C2, one end of resistor R6, and pin 2 of MOSFET D3; one end of resistor R7 is connected to the positive terminal of the 28V input, and the other end is connected to one end of resistor R8 and pin 4 of optocoupler N2; the other end of resistor R8 is connected to the negative terminal of the 28V output; one end of resistor R9 is connected to the positive terminal of the 28V input, and the other end is connected to pin 3 of transistor Q2; pin 2 of transistor Q2 is connected to pin 3 of optocoupler N2; pin 1 of transistor Q2 is connected to one end of resistor R10, pin 2 of voltage regulator D2, one end of capacitor C3, and pin 2 of MOSFET D4; One end of the resistor R5 is connected to the positive end of the 28V input, and the other end is connected to one end of the resistor R6, one end of the capacitor C2, pin 2 of the voltage regulator D1, pin 3 of the transistor Q1, and pin 2 of the MOS transistor D3; pin 1 of the voltage regulator D1 is connected to the negative end of the 28V input; pin 1 of the transistor Q, the other end of the capacitor C2, the other end of the resistor R6, and pin 3 of the MOS transistor D3 are connected to the negative end of the 28V input; Pin 1 of MOS tube D3 is connected to the negative terminal of 28V output; Pin 2 of the MOS transistor D4 is connected to pin 1 of the transistor Q2, one end of the resistor R10, one end of the capacitor C3, and pin 2 of the voltage regulator D2; pin 1 of the MOS transistor D4 is connected to one end of the resistor R12; pin 3 of the MOS transistor D4, pin 1 of the voltage regulator D2, the other end of the capacitor C3, and the other end of the resistor R10 are connected to the negative end of the 28V output; One end of the resistor R11 is connected to the negative end of the 28V input, and the other end is connected to the negative end of the 28V output; one end of the resistor R12 is connected to the positive end of the 28V input, and the other end is connected to pin 1 of the MOS tube D4.

2. An airborne 28V DC overvoltage surge suppression method, characterized in that: The method is implemented based on the airborne 28V DC overvoltage surge suppression circuit described in claim 1, and the steps of the method are as follows: Step 1: When the 28V input is normal, the switch circuit 2 is in the off state, the switch circuit 1 is in the on state, and 28V is directly output; Step 2: When there is an overvoltage surge on the 28V input, the overvoltage detection circuit detects the overvoltage surge and controls the drive circuit to operate; Step 3: The driving circuit drives the switch circuit, so that the switch circuit 2 is in the on state and the switch circuit 1 is in the off state. At this time, the output voltage is equal to the voltage on the voltage divider resistor 2.

3. The method according to claim 2, characterized in that Reasonably set the resistance value of the voltage divider resistor to keep the output voltage within a reasonable voltage range.

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