Delay compensation circuit and lithium battery protection system thereof

Abstract

The invention discloses a delay compensation circuit and a lithium battery protection system thereof. The delay compensation circuit comprises a reference circuit, a short circuit detection circuit, a delay circuit, a voltage-controlled oscillator circuit and a switching tube, and the reference circuit is used for generating a reference voltage source and a current source which do not change along with voltage in a chip; the short circuit detection circuit is used for detecting whether current at two ends of the switch tube exceeds a preset current value; the time delay circuit is used for setting the time delay of the short circuit detection circuit; the switching tube is used for controlling on or off of the charging and discharging path; and the voltage-controlled oscillator circuit is used for controlling the time delay of an oscillator through the voltage of a VM end, and comprises a voltage-controlled voltage source circuit and an oscillating circuit. The magnitude of the reference voltage is adjusted by detecting the short circuit current, and then the period of the oscillating circuit is controlled, so that the protection delay is relatively long when the short circuit current is small, the protection delay is relatively short when the short circuit current is large, and the stability and the reliability of a lithium battery protection system are ensured.

Description

technical field [0001] The invention relates to the technical field of lithium battery protection, in particular to a delay compensation circuit and a lithium battery protection system thereof. Background technique [0002] With the development of microelectronics technology in the 20th century, high requirements have been placed on power supplies. Lithium batteries have entered a large-scale practical stage due to their advantages such as high energy, light weight, long service life, and environmental protection. In applications such as smart phones, notebook computers, and mobile power supplies, the capacity of lithium batteries is getting larger and larger, and the capacity of the battery is as high as several thousand mAH, or even tens of thousands of mAH. [0003] In the prior art, when a lithium battery is short-circuited, the short-circuit current is large, reaching tens of A or even hundreds of A, while the current lithium battery protection chip detects that the sho...

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Problems solved by technology

[0003] In the prior art, when a lithium battery is short-circuited, the short-circuit current is large, reaching tens of A or even hundreds of A, while the current lithium battery protection chip detects that the short-circuit current of the lithium battery reaches or exceeds the threshold, and passes through After the delay set by the corresponding delay circuit, the discharge path is turned off. The traditional lithium battery protection chip uses a fixed delay time. Therefore, after the lithium battery is short-circuited, the delay protection time of different short-circuit currents is the same. If the protection If the delay setting is short, it is easy to trigger the short-circuit protection function when the system is working, causing the switch tube to be turned off by mistake; if the protection delay setting is long, it is easy to accumulate energy and cause the switch tube to burn out when the short-circuit current is large. damage, which will cause the function of the lithium battery protection chip to fail, and even cause the lithium battery to be damaged

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