Level conversion circuit and multi-lithium battery protection system

Abstract

The invention discloses a level conversion circuit and a multi-lithium battery protection system. The level conversion circuit comprises a first capacitor, a second capacitor, a second operational amplifier and a plurality of groups of conversion clocks; the first ends of the plurality of groups of conversion clocks are used as the first input end or the third input end of the level conversion circuit; the second ends of the group of conversion clocks are connected with one end of a second capacitor and the in-phase input end of a second operational amplifier; and the second end of the other group of conversion clocks is connected with the vss end and the other end of the second capacitor, the inverting input end of the second operational amplifier is connected with the output end of the second operational amplifier, and the output end of the second operational amplifier serves as the output end of the level conversion circuit. According to the invention, the level conversion is realized through the resistor plus the operational amplifier or the clock, the capacitor and the operational amplifier, so that the voltages of all ports of the operational amplifier are controlled, the grid electrode of the low-voltage CMOS is conveniently used as the input of the operational amplifier, and the error problem caused by the current flowing into the operational amplifier is solved.

Description

technical field [0001] The invention relates to the technical field of lithium battery protection, in particular to a level conversion circuit and a multi-cell lithium battery protection system. Background technique [0002] When multiple lithium batteries are used in series, it is necessary to accurately detect the voltage value of each battery. Due to the series application, the relative level of each battery is different. In order to facilitate the detection, it is necessary to convert the voltage of each battery into a relative fixed voltage through a level conversion circuit, and then divide the voltage through resistors in series, compare the divided voltage with the reference voltage, and output the comparison result to the control logic module. [0003] In the prior art, the op amp in the level conversion circuit works at the high voltage threshold. Due to the limitation of the integrated circuit technology, usually the high voltage MOS transistor can only withstand ...

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Problems solved by technology

[0003] In the prior art, the op amp in the level conversion circuit works at the high voltage threshold. Due to the limitation of the integrated circuit technology, usually the high voltage MOS transistor can only withstand the high voltage between the source and the drain, while the source and the gate The pole can only withstand 5v voltage, so the op amp can only use the source level as the input level, and the source level as the input, there will be part of the current flowing into the op amp, which will cause detection errors; the existing level conversion circuit is essentially It is a current source, which will produce a voltage drop on the resistor, which will also cause detection errors

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