DALI bus power supply circuit

Abstract

The invention relates to a DALI bus power supply circuit, which comprises a voltage source, a current limiting circuit, a port, a voltage reference element, an amplifier circuit and a feedback circuit; the voltage reference element and the feedback circuit are in parallel; the input end of the voltage reference element and the input end of the feedback circuit are connected with the port respectively; the output end of the voltage reference element and the output end of the feedback circuit are connected with the input end of the amplifier circuit; the output end of the amplifier circuit is connected with the current limiting circuit. According to the DALI bus power supply circuit, the voltage reference element determines the state of the bus device, and the circuit signal is adjusted according to the state of the bus device; the amplifier circuit ensures sufficient voltage drop for the long-distance transmission of the data, thereby reducing the high voltage requirement for the voltage source, and the feedback circuit ensures the stability and reliability of the product.

Description

technical field [0001] The invention relates to the technical field of power supply circuits, in particular to a DALI bus power supply circuit. Background technique [0002] The DALI communication interface protocol has simple coding and reliable communication. The high and low levels are identified by the voltage difference between the two lines. If it is greater than 9.5V, it is high level, and if it is less than 6.5V, it is low level. Common DALI device interface circuits such as Figure 4 As shown, a maximum of 64 bus devices can be connected. The existing DALI bus power supply circuit such as figure 2 As shown, it includes the voltage source, current limiting circuit and port connected in sequence. The voltage source adopts a voltage source of 18-22.5V. The current limiting circuit includes transistor Q1, resistor R1, resistor R15 and compound diode D6, and the interface circuit between the port and DALI equipment connect. [0003] The circuit characteristic of the ...

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Problems solved by technology

[0007] 3. When no bus device is pulled low, the output bus current of the existing DALI bus power supply circuit is greater than 130mA, and the output bus voltage is less than 6.5V, resulting in at least 0.8W higher power consumption of the triode Q1 than the high level. Q1 heats up, reducing equipment reliability

[0008] 4. When there is a short circuit on the bus, there is no short circuit protection function, the power consumption of the transistor Q1 is greater than 2W, it is easy to heat and damage, and the cost increases

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