Vehicle-mounted DCDC converter primary side voltage sampling circuit with low-voltage side power supply

Abstract

The invention discloses a vehicle-mounted DCDC converter primary side voltage sampling circuit with low-voltage side power supply. The circuit comprises a primary side voltage sampling circuit, an isolation circuit and a single-chip microcomputer sampling circuit. An input end of the isolation circuit is connected with an output end of the primary side voltage sampling circuit, and the output endof the isolation circuit is connected with the input end of the single-chip microcomputer sampling circuit; and the input end of the single-chip microcomputer sampling circuit is connected with a DCDCcircuit and then connected with the output end of a vehicle-mounted small storage battery. According to the vehicle-mounted DCDC converter primary side voltage sampling circuit with low-voltage sidepower supply, an additional power supply does not need to be provided for the primary side voltage sampling circuit at a primary side bus end, and a change of a bus voltage can be monitored in real time according to the change of a duty ratio so that the real-time monitoring of the primary side bus voltage is realized; and the whole structure is simple and effective, reliability is high, an isolated power supply does not need to be additionally provided, a PCB layout space is saved, and product cost is saved too.

Description

technical field [0001] The invention relates to the technical field of vehicle-mounted power supply equipment, in particular to a primary-side voltage sampling circuit of a vehicle-mounted DC-DC converter powered by a low-voltage side. Background technique [0002] In power supply products, it is often necessary to sample and monitor the DC voltage of the primary side and the secondary side through the AD sampling port of the single chip microcomputer, but the existing technology needs to provide a set of isolated power supplies for the primary side or the secondary side, so it is necessary Add a winding to the auxiliary power transformer to achieve isolation, or add an isolated DCDC module to provide isolation voltage; the traditional bus voltage isolation sampling circuit (see Figure 5 ) needs to provide one more isolated DCDC power supply, which requires adding isolated power supply chips or auxiliary power transformer windings, increasing the layout area of ​​the PCB, an...

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Problems solved by technology

[0002] In power supply products, it is often necessary to sample and monitor the DC voltage of the primary side and the secondary side through the AD sampling port of the single chip microcomputer, but the existing technology needs to provide a set of isolated power supplies for the primary side or the secondary side, so it is necessary Add a winding to the auxiliary power transformer to achieve isolation, or add an isolated DCDC module to provide isolation voltage; the traditional bus voltage isolation sampling circuit (see Figure 5 ) needs to provide one more isolated DCDC power supply, which requires adding isolated power supply chips or auxiliary power transformer windings, increasing the layout area of ​​the PCB, and increasing product costs; based on the above problems, a vehicle-mounted DCDC converter powered by the low-voltage side Side Voltage Sampling Circuit

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