Adaptive substrate switching circuit structure and battery protection chip

Abstract

The present invention provides an adaptive substrate switching circuit structure and a battery protection chip. The gate of the first MOS transistor Q1 is used as a GP pin, and the drain of the first MOS transistor Q1 is respectively connected to the source of the third MOS transistor Q3. and the gate of the fourth MOS transistor Q4, the source of the first MOS transistor Q1 is respectively connected to the source of the fourth MOS transistor Q4 and the gate of the third MOS transistor Q3, the substrate of the first MOS transistor Q1 is connected to the second MOS transistor The drain of the transistor Q2; the gate of the second MOS transistor Q2 is used as the GB pin, and the source of the second MOS transistor Q2 is respectively connected to the substrate of the second MOS transistor Q2, the substrate of the third MOS transistor Q3, and the third MOS transistor The drain of the transistor Q3, the drain of the fourth MOS transistor Q4, and the substrate of the fourth MOS transistor Q4. The self-adaptive substrate switching scheme proposed by the present invention enables the lithium battery protection chip to be integrated in a single chip, realizes charging and discharging functions at the same time, and reduces the chip area and cost.

Description

technical field [0001] The present invention relates to the technical field of batteries, in particular, to an adaptive substrate switching circuit structure and a battery protection chip. Background technique [0002] At present, the traditional lithium battery protection chip solutions such as figure 1 As shown in the figure, the chip controls the on-off of FET1 and FET2 through pins D0 and C0 to complete the charging and discharging of lithium batteries and their special functions. The working principle is as follows: (1 refers to the high-level state, 0 refers to the low-level state) [0003] a. Normal state: C0=1, D0=1, the corresponding charging tube FET2 and discharge tube FET1 are turned on to complete the normal charging and discharging functions; [0004] b. Overcharge state: D0=1, C0=0, the charging tube FET2 is turned off, and the discharge tube FET1 is turned on. At this time, the positive pole of the battery BAT is connected to the positive pole of the load ...

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Problems solved by technology

But this patent document still has the following defects: (1) in the circuit schematic diagram, the positive and negative poles of the parasitic diodes DP1 and DP2 of the MN switch tube are connected incorrectly, which is closely related to the specific working state: (2) when the chip is in an overcharged state, the main After the switch tube is turned off, a discharge path cannot be formed for discharging. When the chip is in an over-discharge state, after the main switch tube is turned off, the charger is connected, and a charging path cannot be formed for charging.

However, this patent document still has the disadvantage of not being able to perform substrate switching adaptively according to the input voltage at both ends.

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