Direct current power supply protection circuit and device for director's console

Abstract

The application relates to a director's console direct-current power supply protection circuit and device, which comprises a power supply input positive terminal, a power supply output terminal, a double-channel PMOS tube, a sampling resistor and a switch control unit; the double-channel PMOS tube is connected in series on a power supply path as a main power switch; the sampling resistor converts the current flowing through the main loop into a voltage difference; the switch control unit detects the voltage difference, and when the voltage difference exceeds a preset threshold value due to a short circuit in the rear stage, the switch control unit is turned on and the gate of the double-channel PMOS tube is pulled up to the power supply voltage, so that the main power switch is forced to be cut off to cut off the power supply; after the short circuit fault is removed, the main power switch is automatically restored to be turned on, and it is not necessary to re-power or manually reset; the circuit is also integrated with an anti-reverse connection module, an overvoltage protection module and a slow start module; the application realizes hierarchical protection through full hardware, can keep low power consumption and not be hot in a long-time short circuit state, effectively avoids device burning, and improves the reliability of director's console power supply.

Description

Technical Field

[0001] This invention relates to the field of DC power supply protection technology for broadcast control stations, and more specifically, to a DC power supply protection circuit and device for broadcast control stations. Background Technology

[0002] With the rapid development of converged media live streaming, studio program production, and outdoor live streaming industries, the control room, as the core equipment for video signal switching and scheduling, has extremely high requirements for power supply stability. Existing control room power supply circuits generally suffer from the following defects: 1. Reverse connection protection is unreliable: It often uses a single diode connected in series in the circuit. If the broadcast console shares a ground with other equipment, the high voltage will directly impact the ground network when reverse connected, causing damage to the connected equipment.

[0003] 2. Lack of soft start: The charging of the back-end capacitor at the moment of power-on will generate a huge surge current, which can easily cause the MOSFET or power chip to break down.

[0004] 3. No overvoltage or overcurrent protection: When the adapter malfunctions or the circuit is short-circuited, there is no effective shutdown mechanism, which can easily lead to component burnout, PCB trace overheating, or even damage to the entire circuit, resulting in high maintenance costs.

[0005] 4. Cost and complexity: Using dedicated protection chips or software control increases cost and design complexity, and reduces flexibility.

[0006] Therefore, there is an urgent need for a comprehensive protection circuit that is entirely hardware-based, low-cost, and highly reliable to solve the above problems. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a DC power supply protection circuit for a broadcast control console, and also to provide a broadcast control console device, in view of the above-mentioned defects of the prior art.

[0008] The technical solution adopted by this invention to solve its technical problem is: Construct a DC power supply protection circuit for a broadcast control console, comprising: The positive terminal of the power input is used to connect a DC power supply; The power output terminal is used to supply power to subsequent circuits. A dual-channel PMOS transistor is connected in series in the power supply path between the positive terminal of the power input and the power output terminal, serving as the main power switch; A sampling resistor, connected in series in the power supply path, is used to convert the current flowing through the power supply path into a voltage difference; A switch control unit, the control terminal of which is coupled to both ends of the sampling resistor to detect the voltage difference, and the power supply terminal of which is coupled to the positive power input terminal; When a short circuit occurs in the subsequent circuit, the voltage difference across the sampling resistor increases to the point that the switch control unit is turned on. The positive terminal of the power input supplies power to the gate of the dual-channel PMOS transistor via the turned-on switch control unit, causing the gate-source voltage difference of the dual-channel PMOS transistor to approach zero. The dual-channel PMOS transistor is then turned off, cutting off the power supply path. When the short-circuit fault in the subsequent circuit is cleared, the voltage difference across the sampling resistor disappears, the switch control unit turns off, and the dual-channel PMOS transistor automatically resumes conduction.

[0009] The DC power supply protection circuit for the broadcast control station described in this invention includes a dual-channel PMOS transistor comprising two PMOS transistors, the drains of the two PMOS transistors being connected to the power output terminal, the gates of the two PMOS transistors being connected to each other, and the sources of the two PMOS transistors being connected to the positive power input terminal. The switch control unit includes a first PNP transistor, the base of which is coupled to one end of the sampling resistor, and the emitter of which is coupled to the positive terminal of the power input. The collector of the first NPN transistor is connected to the gates of the two PMOS transistors via a first low-dropout Schottky diode and a sixth resistor connected in series, and is coupled to the other end of the sampling resistor, which is connected to the positive terminal of the power input.

[0010] The DC power supply protection circuit for the broadcast control station described in this invention includes a first resistor and a second resistor connected in parallel to the base of the first PNP transistor. The other end of the first resistor is connected to one end of the sampling resistor, and the other end of the second resistor is connected to the power output terminal.

[0011] The DC power supply protection circuit for the broadcast control console according to the present invention further includes an overvoltage protection module. The overvoltage protection module includes a first Zener diode and a second PNP transistor. The emitter of the second PNP transistor is coupled to the other end of the sampling resistor. The collector of the second PNP transistor is connected to the gates of the two PMOS transistors via a second low-dropout Schottky diode and a sixth resistor connected in series. The base of the second PNP transistor is connected to a third resistor. The other end of the third resistor is connected in parallel to a fourth resistor and the negative terminal of the Zener diode. The positive terminal of the first Zener diode is grounded. The other end of the fourth resistor is connected to the other end of the sampling resistor.

[0012] The DC power supply protection circuit for the broadcast control console described in this invention further includes a soft-start capacitor. One end of the soft-start capacitor is connected to the base of the second PNP transistor, the other end of the soft-start capacitor is connected to the fifth resistor, and the other end of the soft-start capacitor is also connected to the gates of the two PMOS transistors via the sixth resistor; the other end of the fifth resistor is connected to system ground.

[0013] The DC power supply protection circuit for the broadcast control console according to the present invention further includes a reverse connection protection module. The reverse connection protection module includes a first N-channel MOSFET and a second N-channel MOSFET; the drains of both the first and second N-channel MOSFETs are connected to the negative terminal of the power input and grounded; the gates of both the first and second N-channel MOSFETs are connected to one end of a sixth resistor, the other end of which is connected to the positive terminal of the power input; and the sources of both the first and second N-channel MOSFETs are connected to system ground.

[0014] The DC power supply protection circuit for the broadcast control console of the present invention includes a seventh resistor and a first capacitor connected to the gate of the first N-channel MOSFET; an eighth resistor and a second capacitor connected to the gate of the first N-channel MOSFET; the other ends of the seventh resistor and the eighth resistor are both connected to the sixth resistor; and the other ends of the first capacitor and the second capacitor are both connected to system ground.

[0015] The DC power supply protection circuit for the broadcast control station described in this invention includes a sixth resistor connected to one end of a ninth resistor and the negative terminal of a second Zener diode, and the other end of the ninth resistor and the positive terminal of the second Zener diode both connected to system ground.

[0016] The DC power supply protection circuit for the broadcast control station described in this invention includes a TVS diode connected to the positive terminal of the power input, and the other end of the TVS diode being grounded.

[0017] A broadcast control station device, wherein the broadcast control station device is provided with a broadcast control station DC power supply protection circuit as described above.

[0018] The beneficial effects of this invention are as follows: 1. Intelligent overcurrent protection: It adopts sampling resistor sampling and utilizes the Vbe threshold characteristics of transistor to achieve the effect of breaking the circuit immediately after a short circuit, cooling down immediately after the circuit is broken, and turning on immediately after the fault is cleared. It eliminates the need for a self-locking circuit, greatly simplifying the design.

[0019] 2. No damage from long-term short circuit: After being turned off, there is no large current in the main circuit, and the sampling resistor and MOSFET are in a low power consumption state. Even if short-circuited for a long time, they will not get hot or burn out.

[0020] 3. Multiple isolation protection: Overvoltage and overcurrent control paths are isolated by low-dropout Schottky diodes, providing strong anti-interference capabilities.

[0021] 4. Low cost and high flexibility: Built with all discrete components, the protection threshold can be easily set by adjusting the sampling resistor value (Ohm's law), and it is compatible with different power control console models. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the present invention will be further described below in conjunction with the accompanying drawings and embodiments. The drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort: Figure 1 This is a schematic diagram of the reverse connection and surge protection function circuit of the DC power supply protection circuit for the broadcast control station according to a preferred embodiment of the present invention. Figure 2 This is a schematic diagram of the soft-start, overvoltage protection, and overcurrent protection functions of the DC power supply protection circuit for the broadcast control console according to a preferred embodiment of the present invention (the connecting line at the bottom of the figure is...). Figure 1 (Connect the rightmost connecting line). Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, a clear and complete description will be provided below in conjunction with the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the protection scope of the present invention.

[0024] The preferred embodiment of the present invention includes a DC power supply protection circuit for the broadcast control console, such as... Figure 1 As shown, see also Figure 2 This includes the positive power input terminal, used to connect to a DC power supply; The power output terminal is used to supply power to subsequent circuits. The dual-channel PMOS transistor U27 is connected in series in the power supply path between the positive terminal of the power input and the power output terminal, serving as the main power switch. The sampling resistor R167 is connected in series in the power supply path to convert the current flowing through the power supply path into a voltage difference. The switch control unit has its control terminal coupled to both ends of the sampling resistor to detect the voltage difference, and its power supply terminal coupled to the positive terminal of the power input. When a short circuit occurs in the subsequent circuit, the voltage difference across the sampling resistor R167 increases to the point that the switch control unit is turned on. The positive terminal of the power input supplies power to the gate of the dual-channel PMOS transistor through the turned-on switch control unit, causing the gate-source voltage difference of the dual-channel PMOS transistor U27 to approach zero. The dual-channel PMOS transistor is then turned off, cutting off the power supply path. When the short-circuit fault in the subsequent circuit is cleared, the voltage difference across the sampling resistor R167 disappears, the switch control unit turns off, and the dual-channel PMOS transistor U27 automatically resumes conduction.

[0025] The beneficial effects of this invention are as follows: 1. Intelligent overcurrent protection: It adopts sampling resistor sampling and utilizes the Vbe threshold characteristics of transistor to achieve the effect of breaking the circuit immediately after a short circuit, cooling down immediately after the circuit is broken, and turning on immediately after the fault is cleared. It eliminates the need for a self-locking circuit, greatly simplifying the design.

[0026] 2. No damage from long-term short circuit: After being turned off, there is no large current in the main circuit, and the sampling resistor and MOSFET are in a low power consumption state. Even if short-circuited for a long time, they will not get hot or burn out.

[0027] 3. Multiple isolation protection: Overvoltage and overcurrent control paths are isolated by low-dropout Schottky diodes, providing strong anti-interference capabilities.

[0028] 4. Low cost and high flexibility: Built with all discrete components, the protection threshold can be easily set by adjusting the sampling resistor value (Ohm's law), and it is compatible with different power control console models.

[0029] The specific circuit description is as follows: The dual-channel PMOS transistor U27 includes two PMOS transistors. The drains of the two PMOS transistors are connected to the power output terminal, the gates of the two PMOS transistors are connected together, and the sources of the two PMOS transistors are connected to the positive power input terminal. The switch control unit includes a first PNP transistor Q2. The base of the first PNP transistor Q2 is coupled to one end of the sampling resistor R167, and the emitter of the first NPN transistor Q2 is coupled to the positive power input terminal. The collector of the first NPN transistor Q2 is connected to the gates of the two PMOS transistors through a first low-dropout Schottky diode D23 and a sixth resistor R161 connected in series, and coupled to the other end of the sampling resistor R167. The other end of the sampling resistor R167 is connected to the positive power input terminal. The base of the first PNP transistor Q2 is connected in parallel with a first resistor R169 and a second resistor R171. The other end of the first resistor R169 is connected to one end of the sampling resistor R167, and the other end of the second resistor R171 is connected to the power output terminal.

[0030] Overcurrent protection is activated by calculating the voltage difference at the base (B) of Q2. During a short circuit, +12V and +12_OUT will be approximately 1V lower than DC +12V, causing Q2 to conduct. DC +12V then flows through the gate (G) of D23 and R161, causing U27 to cut off. When the current exceeds the set value during a short circuit, U27 cuts off the output. Once the short circuit is resolved, the circuit automatically returns to normal, effectively protecting the components and the circuit board.

[0031] The circuit also includes an overvoltage protection module; The overvoltage protection module includes a first Zener diode D16 and a second PNP transistor Q1. The emitter of the second PNP transistor Q1 is coupled to the other end of the sampling resistor R167. The collector of the second PNP transistor Q1 is connected to the gates of two PMOS transistors via a second low-dropout Schottky diode D24 and a sixth resistor R161 connected in series. The base of the second PNP transistor Q1 is connected to a third resistor R163. The other end of the third resistor R163 is connected in parallel to a fourth resistor R162 and the negative terminal of the first Zener diode D16. The positive terminal of the first Zener diode D16 is grounded. The other end of the fourth resistor R162 is connected to the other end of the sampling resistor R167.

[0032] Under normal input voltage, Zener diode D16 is cut off. At this time, DC+12V flows through R162 and R163 to the base of PNP transistor Q1. Since the emitter of Q1 is connected to DC+12V, Vbe=0, and Q1 is cut off. The gate of PMOS U27 is grounded through R161 and R164. Vgs≤0, and U27 is turned on, realizing the conduction of DC+12V and +12V_OUT, outputting 12V voltage to the next stage. When the input voltage exceeds 24V, Zener diode D16 breaks down in reverse, clamping the base potential of PNP transistor Q1, causing Q1 to conduct. The overvoltage reaches the gate of PMOS U27 through D24 and R161. Since the voltage drop across the transistor is very small, it can be approximated as Vgs=0, and U27 is turned off, resulting in no output from the next stage, thus achieving overvoltage protection.

[0033] In addition, D24 and D23 isolate the voltage reversal of Q1 and Q2 when they are working. The current through D24 and D23 is very small, and the voltage difference is 0.2V. Since the input DC+12V is connected to the emitter of Q1 and Q2, the output voltage of D24 and D23 is greater than the source of U27, which can turn off U27.

[0034] The circuit also includes a soft-start capacitor C197; One end of the soft-start capacitor C197 is connected to the base of the second PNP transistor Q1, and the other end of the soft-start capacitor C197 is connected to the fifth resistor R164. The other end of the soft-start capacitor C197 is also connected to the gates of the two PMOS transistors via the sixth resistor R161; the other end of the fifth resistor R164 is connected to system ground.

[0035] Due to the influence of capacitor C197, there is a turn-off delay. The capacitor characteristics cannot change abruptly, thus achieving slow start and slow turn-off.

[0036] The circuit also includes a reverse connection protection module; The reverse connection protection module includes a first N-channel MOSFET Q7 and a second N-channel MOSFET Q8. The drains of both Q7 and Q8 are connected to the negative terminal of the power input and grounded. The gates of both Q7 and Q8 are connected to one end of a sixth resistor R159, the other end of which is connected to the positive terminal of the power input. The sources of both Q7 and Q8 are connected to system ground. The gate of the first N-channel MOSFET Q7... Connect the seventh resistor R177 and the first capacitor C200; the gate of the first N-channel MOSFET Q7 is connected to the eighth resistor R178 and the second capacitor C207; the other ends of the seventh resistor R177 and the eighth resistor R178 are both connected to the sixth resistor R159; the other ends of the first capacitor C200 and the second capacitor C207 are both connected to system ground; one end of the sixth resistor R159 is connected to one end of the ninth resistor R172 and the negative terminal of the second Zener diode D6, and the other end of the ninth resistor R172 and the positive terminal of the second Zener diode D6 are both connected to system ground; R177 and R178 are gate series resistors, whose main functions are to dampen oscillations, regulate switching speed (reduce EMI), and limit peak drive current to ensure that Q7 and Q8 can operate stably and reliably.

[0037] Soft start and buffer: Q7 is the high-side drive transistor; when Q7 turns on, if there is no C200, its gate voltage will jump instantly, which may cause the MOSFET to turn on too quickly and generate oscillation or peak current; C200 is connected in parallel between the gate and the source (or in conjunction with R172 to form an RC time constant) to make the turn-on process of Q7 slightly smoother and reduce voltage overshoot.

[0038] Soft start and buffer: Q8 is the high-side drive transistor. When Q8 turns on, without C207, its gate voltage will jump instantaneously, which may cause the MOSFET to turn on too quickly, resulting in oscillation or peak current. C207 is connected in parallel between the gate and source (or in conjunction with R172 to form an RC time constant) to make the turn-on process of Q8 slightly smoother and reduce voltage overshoot.

[0039] (1) Under normal 12V power supply; The gate voltage is obtained by voltage division using R159 and R172: ; ; ; ; ; At this time, the voltage across D6 is 6V, which is lower than its 10V regulation value. The Zener diode does not break down and does not work.

[0040] Gate-source voltage of a MOSFET: VGS = VG VS=6V 0V = 6V. 6V is greater than the conduction threshold of 50N04 (typically 2~4V) and less than its VGS (±20V) rating, the tube can conduct reliably.

[0041] (2) Protection against overvoltage / surge; When the input voltage rises abnormally (e.g., surge, overshoot to 20V), the gate voltage after voltage division will increase: ; ; ; ; When V_G exceeds 10V, D6 breaks down in reverse and enters a regulated state, clamping the gate voltage at 10V.

[0042] At this time, VGS = 10V, which is still far below the 20V withstand voltage of 50N04, effectively protecting the gate from overvoltage breakdown.

[0043] The positive terminal of the power input is connected to a TVS diode D15, and the other end of the TVS diode D15 is grounded for surge protection.

[0044] When the power supply is not connected, the input voltage is less than the Vgs threshold voltage of the NMOS of Q7 and Q8, or the power supply is reversed, Q7 and Q8 will turn off, and the ground network will be disconnected to protect the circuit.

[0045] The circuit using this application has the following functions: 1. Surge protection (TVS tube D15), immunity level 4, contact discharge ±8kV, air discharge ±15kV.

[0046] 2. Reverse polarity protection (50N04 N-channel MOSFET), BVDSS-40V, RDSON-11mΩ, ID-45A, compliant with reverse polarity protection operation.

[0047] 3. A 100nF capacitor (C200 / C207) is connected in parallel between the gate and source of each MOSFET to filter out spike interference and prevent the MOSFET from being falsely turned on.

[0048] 4. A 100Ω resistor (R177 / R178) is connected in series with the gate of each MOSFET to balance the drive current and avoid inconsistent operating states of the transistors.

[0049] 5. Two 50N04s are connected in parallel to reduce on-resistance and improve high-current capability.

[0050] 6. Overvoltage shutdown and overcurrent protection are provided with low-voltage-drop Schottky isolation (D24 D23), ensuring that their operation does not interfere with each other.

[0051] 7. Overcurrent protection: The protection current value for each model can be set according to Ohm's law.

[0052] A broadcast control station device, wherein the broadcast control station device is provided with a DC power supply protection circuit as described above.

[0053] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A DC power supply protection circuit for a broadcast control console, characterized in that, include: The positive terminal of the power input is used to connect a DC power supply; The power output terminal is used to supply power to subsequent circuits. A dual-channel PMOS transistor is connected in series in the power supply path between the positive terminal of the power input and the power output terminal, serving as the main power switch; A sampling resistor, connected in series in the power supply path, is used to convert the current flowing through the power supply path into a voltage difference; A switch control unit, the control terminal of which is coupled to both ends of the sampling resistor to detect the voltage difference, and the power supply terminal of which is coupled to the positive power input terminal; When a short circuit occurs in the subsequent circuit, the voltage difference across the sampling resistor increases to the point that the switch control unit is turned on. The positive terminal of the power input supplies power to the gate of the dual-channel PMOS transistor via the turned-on switch control unit, causing the gate-source voltage difference of the dual-channel PMOS transistor to approach zero. The dual-channel PMOS transistor is then turned off, cutting off the power supply path. When the short-circuit fault in the subsequent circuit is cleared, the voltage difference across the sampling resistor disappears, the switch control unit turns off, and the dual-channel PMOS transistor automatically resumes conduction.

2. The DC power supply protection circuit for the broadcast control station according to claim 1, characterized in that, The dual-channel PMOS transistor includes two PMOS transistors, with the drains of the two PMOS transistors connected to the power output terminal, the gates of the two PMOS transistors connected to each other, and the sources of the two PMOS transistors connected to the positive power input terminal. The switch control unit includes a first PNP transistor, the base of which is coupled to one end of the sampling resistor, and the emitter of which is coupled to the positive terminal of the power input. The collector of the first NPN transistor is connected to the gates of the two PMOS transistors via a first low-dropout Schottky diode and a sixth resistor connected in series, and is coupled to the other end of the sampling resistor, which is connected to the positive terminal of the power input.

3. The DC power supply protection circuit for the broadcast control station according to claim 2, characterized in that, The base of the first PNP transistor is connected in parallel with a first resistor and a second resistor. The other end of the first resistor is connected to one end of the sampling resistor, and the other end of the second resistor is connected to the power output terminal.

4. The DC power supply protection circuit for the broadcast control station according to claim 2, characterized in that, The circuit also includes an overvoltage protection module; The overvoltage protection module includes a first Zener diode and a second PNP transistor. The emitter of the second PNP transistor is coupled to the other end of the sampling resistor. The collector of the second PNP transistor is connected to the gates of the two PMOS transistors via a second low-dropout Schottky diode and a sixth resistor connected in series. The base of the second PNP transistor is connected to a third resistor. The other end of the third resistor is connected in parallel to a fourth resistor and the negative terminal of the first Zener diode. The positive terminal of the first Zener diode is grounded. The other end of the fourth resistor is connected to the other end of the sampling resistor.

5. The DC power supply protection circuit for the broadcast control station according to claim 4, characterized in that, The circuit also includes a soft-start capacitor; One end of the soft-start capacitor is connected to the base of the second PNP transistor, the other end of the soft-start capacitor is connected to the fifth resistor, and the other end of the soft-start capacitor is also connected to the gates of the two PMOS transistors via the sixth resistor; the other end of the fifth resistor is connected to system ground.

6. The DC power supply protection circuit for the broadcast control console according to claim 1, characterized in that, The circuit also includes a reverse connection protection module; The reverse connection protection module includes a first N-channel MOSFET and a second N-channel MOSFET; the drains of both the first and second N-channel MOSFETs are connected to the negative terminal of the power input and grounded; the gates of both the first and second N-channel MOSFETs are connected to one end of a sixth resistor, the other end of which is connected to the positive terminal of the power input; and the sources of both the first and second N-channel MOSFETs are connected to system ground.

7. The DC power supply protection circuit for the broadcast control station according to claim 6, characterized in that, The gate of the first N-channel MOSFET is connected to a seventh resistor and a first capacitor; the gate of the first N-channel MOSFET is connected to an eighth resistor and a second capacitor; the other ends of the seventh resistor and the eighth resistor are both connected to the sixth resistor; the other ends of the first capacitor and the second capacitor are both connected to system ground.

8. The DC power supply protection circuit for the broadcast control station according to claim 7, characterized in that, One end of the sixth resistor is connected to one end of the ninth resistor and the negative terminal of the second Zener diode, and the other end of the ninth resistor and the positive terminal of the second Zener diode are both connected to system ground.

9. The DC power supply protection circuit for the broadcast control console according to claim 1, characterized in that, The positive terminal of the power input is connected to a TVS diode, and the other end of the TVS diode is grounded.

10. A broadcast control station device, characterized in that, The broadcast control unit is equipped with a DC power supply protection circuit as described in any one of claims 1 to 9.

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