Broadcast power dynamic switching circuit based on load detection

Abstract

A broadcast power dynamic switching circuit based on load detection comprises: an MCU control unit for sending instructions to each module; an input circuit comprising at least two input sources; a detection circuit connected with the MCU control unit for detecting the current load to feed back to the MCU control unit; a switching circuit connected with the input circuit, according to the detection feedback of the detection circuit, so that the MCU control unit sends a signal to the switching circuit to turn on the corresponding input source; and an output circuit connected with the switching circuit for outputting the corresponding voltage. The application adopts the mode of multiple power input, one of which is the main power supply and the other is the standby power supply. When the standby power capacity is insufficient, charging is carried out to avoid possible switching failure when the standby power capacity is insufficient. In addition, the switching time is short, the response time is fast, the load state is dynamically monitored, and the system power supply safety is protected.

Description

Technical Field

[0001] This utility model relates to the field of broadcasting systems, and in particular to a dynamic switching circuit for broadcasting power supply based on load detection. Background Technology

[0002] Traditional broadcast power supply systems suffer from several pain points, including: switching delays (traditional relay switching requires 20-50ms, easily causing audio interruptions during high-voltage start-up and shutdown); transient current misjudgment (the instantaneous current at startup of broadcast equipment can reach 3-5 times the steady-state value, such as power transistor surges in amplifiers), and existing detection circuits cannot accurately distinguish between transient and steady-state loads); insufficient backup power capacity (24V backup power needs to be boosted to 220V via DC / AC inverters, but traditional solutions do not consider the dynamic efficiency of the boost circuit (efficiency is only 60%-75% at full load); low conversion efficiency (lack of dynamic load monitoring, potentially leading to switching failures when backup power capacity is insufficient); and poor electromagnetic interference tolerance (the strong electromagnetic environment of broadcast equipment rooms can easily distort detection signals, causing erroneous switching). Utility Model Content

[0003] To address the aforementioned issues, this technical solution provides a dynamic switching circuit for broadcast power supply based on load detection.

[0004] To achieve the above objectives, the technical solution is as follows: A dynamic switching circuit for broadcast power supply based on load detection, comprising: The MCU control unit is used to send instructions to various modules; The input circuit shall include at least two input sources; A detection circuit, connected to the MCU control unit, is used to detect the current load and provide feedback to the MCU control unit. A switching circuit, connected to the input circuit, sends a signal to the switching circuit based on the detection feedback from the detection circuit, thereby turning on the corresponding input source. The output circuit is connected to the switching circuit and outputs the corresponding voltage.

[0005] In some embodiments, the input circuit includes at least: The first input interface is used to receive mains power and, after passing through the AC-DC conversion circuit, provide a first voltage to the switching circuit. The second input interface is used to receive the voltage from the charging circuit, and after passing through the DC-DC conversion circuit, it provides a second voltage to the switching circuit.

[0006] The beneficial effects of this application are: This application adopts a multi-channel power input method, with one channel serving as the main power supply and the other as the backup power supply. The status of the backup power supply is monitored, and when the backup power capacity is insufficient, it is charged to avoid possible switching failure when the backup power capacity is insufficient. In addition, the switching time is short and the response time is fast, achieving dynamic monitoring of the load status and protecting the system power safety. Attached Figure Description

[0007] To more clearly illustrate the technical solutions in the embodiments of this utility model, the accompanying drawings used in the description of the embodiments will be briefly introduced below.

[0008] Figure 1 This is a structural schematic diagram of an embodiment of the present utility model; Figure 2 This is a schematic diagram of the input circuit structure of an embodiment of the present invention. Figure 1 ; Figure 3 This is a schematic diagram of the input circuit structure of an embodiment of the present invention. Figure 2 ; Figure 4 This is a schematic diagram of the AC-DC circuit structure according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the switching circuit structure according to an embodiment of the present invention; Figure 6 This is a schematic diagram of the MCU control unit structure according to an embodiment of the present invention. Detailed Implementation

[0009] To make the technical problems solved, technical solutions, and beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0010] Please refer to Figure 1-6 As shown, a dynamic switching circuit for broadcast power supply based on load detection includes: The MCU control unit is used to send instructions to various modules; The input circuit shall include at least two input sources; A detection circuit, connected to the MCU control unit, is used to detect the current load and provide feedback to the MCU control unit. A switching circuit, connected to the input circuit, sends a signal to the switching circuit based on the detection feedback from the detection circuit, thereby turning on the corresponding input source. The output circuit is connected to the switching circuit and outputs the corresponding voltage.

[0011] ① AC-220V input interface circuit; Functions: Mains power connection and primary protection; Working principle: EMC filtering: A two-stage LC filter design is adopted. The first stage uses an X2 capacitor and a common-mode inductor to suppress common-mode interference, and the second stage uses a Y capacitor to filter out differential-mode noise.

[0012] Surge protection: A varistor is connected in parallel to the input side to absorb lightning surges of ≤6kV; a gas discharge tube enables rapid discharge between the phase line and the ground line with a response time of ≤100ns.

[0013] Safety isolation: Input stage series time-delay fuse to prevent overcurrent from burning out the PCB.

[0014] ② DC-24V input interface circuit; Functions: Backup power access and isolation protection; Working principle: Reverse protection: A Schottky diode is connected in series with the positive input terminal to prevent reverse power flow from the main or backup power source.

[0015] Transient suppression: A TVS diode is connected in parallel at the input terminal to clamp the voltage to ≤30V and absorb ±50A surge current.

[0016] ③ AC-DC circuit (AC220V to ±DC150V); Function: High-efficiency AC power to high-voltage DC power conversion; Working principle: Topology: Active PFC + full-bridge LLC resonant, the PFC stage improves the power factor to >0.98, the LLC stage achieves zero-voltage switching, and the full-load efficiency is ≥92%.

[0017] High voltage generation: The high-frequency transformer is driven by a full-bridge MOS, and the secondary full-wave rectified and filtered by LC to output ±150V with ripple ≤200mVpp.

[0018] Heat dissipation design: The MOSFET and rectifier diode are mounted on copper-based heat sinks (thermal resistance <1.5℃ / W), and forced air cooling is used to achieve a continuous output of 1000W.

[0019] ④ DC-DC circuit (DC24V to ±DC150V); Functions: Backup power boost and symmetrical output; Working principle: Push-pull boost: Two MOSFETs drive a high-frequency transformer, and the secondary voltage doubler rectifier generates ±150V with an efficiency of ≥88%.

[0020] Voltage regulation control: A PWM controller is used to sample the output voltage through a ±1% precision voltage divider resistor and dynamically adjust the duty cycle.

[0021] Overload protection: The peak current limit is set to 12A. After triggering, it enters hiccup mode to prevent the device from overheating.

[0022] ⑤ Switching circuit and detection circuit; Functions: Seamless switching between primary and backup power and load monitoring; Working principle: Contactless switching: The main power channel uses optocoupler-driven MOSFETs, and the backup power channel uses SSRs, with a switching time of <5ms.

[0023] Current detection: The amplifier acquires the voltage of a 10mΩ sampling resistor, with a dynamic range of 0-50A and an accuracy of ±1%.

[0024] Fault diagnosis: The micro-current detection circuit (≤10μA) determines the continuity of the line, and triggers an MCU alarm when the threshold is exceeded.

[0025] ⑥MCU control unit; Functions: System management and intelligent decision-making; Working principle: Core algorithm: The STM32F407 has a built-in PID algorithm to adjust the PWM duty cycle, combined with an ADC (12-bit) to monitor voltage / current in real time, and the switching logic response time is <1ms.

[0026] Communication interface: RS485 connection to host computer, Modbus protocol for uploading status data; CAN bus reserved for expanding IoT functionality.

[0027] Redundancy design: Dual watchdog timers (hardware WDT + software WDT) ensure stable system operation and fault recovery time <50ms.

[0028] ⑦ Output interface circuit; Functions: High voltage output and protection; Working principle: Symmetrical output: ±150V is connected to the terminal block after being filtered by a π-type filter, with a positive and negative symmetry deviation of ≤3%.

[0029] Overvoltage protection: The comparator monitors the output voltage, and shuts off the drive signal and triggers self-locking when the voltage exceeds ±165V.

[0030] 24V Auxiliary Output: The step-down module provides 24V / 4A power for the detection circuit and MCU, with an efficiency of ≥90%.

[0031] ⑧ AC-DC charging circuit; Function: Intelligent charging management with backup power; Working principle: Three-stage charging: constant current (0.1C) → constant voltage (28.8V) → float charging (27V), with temperature compensation (-3mV / ℃) achieved in conjunction with an NTC thermistor.

[0032] Efficiency optimization: Synchronous rectification Buck circuit achieves AC220V to 28.8V conversion.

[0033] Capacity monitoring: Coulomb meter calculates battery SOC in real time.

[0034] In this embodiment, the input circuit includes at least: The first input interface is used to receive mains power and, after passing through the AC-DC conversion circuit, provide a first voltage to the switching circuit. The second input interface is used to receive the voltage from the charging circuit, and after passing through the DC-DC conversion circuit, it provides a second voltage to the switching circuit.

[0035] This application features millisecond-level dynamic switching capability, replacing relays with contactless electronic switches. Employing MOSFET + optocoupler isolation, the switching time is <5ms, far exceeding traditional relay solutions (>50ms), meeting the seamless switching requirements of fire alarm broadcasting GB 16806-2018. Zero-spark switching avoids the risk of arcing due to high voltage differential (220V main power vs. 24V backup power), improving system safety.

[0036] Secondly, it features a high-efficiency conversion design. The AC-DC stage utilizes a PFC+LLC topology to achieve an efficiency of ≥92% (1000W full load) and standby power consumption of <5μF. The DC-DC stage employs a full-bridge inverter and voltage doubler rectification, with an output symmetry deviation of ±150V ≤±3%, reducing power amplifier losses. Cost reduction and efficiency improvement measures include integrating current sensing, optocoupler drive, and MOSFET switching on the PCB to reduce external circuit costs.

[0037] The above description is only a preferred embodiment of this application and is not intended to limit the scope of implementation of this application. Any other embodiments whose principles and basic structures are the same as or similar to those of this application are within the protection scope of this application.

Claims

1. A load detection based broadcast power dynamic switching circuit, characterized in that, include; The MCU control unit is used to send instructions to various modules; The input circuit shall include at least two input sources; A detection circuit, connected to the MCU control unit, is used to detect the current load and provide feedback to the MCU control unit. A switching circuit, connected to the input circuit, sends a signal to the switching circuit based on the detection feedback from the detection circuit, thereby turning on the corresponding input source; The output circuit is connected to the switching circuit and outputs the corresponding voltage.

2. The load detection based broadcast power dynamic switching circuit according to claim 1, wherein: The input circuit includes at least: The first input interface is used to receive mains power and, after passing through the AC-DC conversion circuit, provide a first voltage to the switching circuit. The second input interface is used to receive the voltage from the charging circuit, and after passing through the DC-DC conversion circuit, it provides a second voltage to the switching circuit.

3. The load detection based broadcast power supply dynamic switching circuit according to claim 1, wherein: The switching circuit includes a MOS transistor for driving.

4. The load detection based broadcast power supply dynamic switching circuit according to claim 1, wherein: The detection circuit detects current through a sampling resistor.

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