Battery protective circuit with single charge-discharge power tube

Abstract

The invention provides a battery protective circuit with a single charge-discharge power tube. The battery protective circuit with the single charge-discharge power tube comprises a battery cell, an inductor L 1, a third p-channel metal oxide semiconductor (PMOS) transistor, an n-channel metal oxide semiconductor (NMOS) transistor MN3 and a pressure boosting-battery protective circuit. The battery cell is connected between a battery cell node and a ground node, the inductor L 1 is connected between the battery cell node and a middle node, and the PMOS transistor is connected between the middle node and a first power source end. When the voltage of the middle node is smaller than the voltage of the first power source end, a lining body end of the third PMOS transistor is controlled to be connected with the first power source end. When the voltage of the middle node is bigger than the voltage of the first power source end, the lining body end of the third PMOS transistor is controlled to be connected with the middle node. The pressure boosting-battery protective circuit controls breakover and turn-off of the NMOS transistor MN3 and the third PMOS transistor, and therefore when the voltage of the battery cell node is bigger than a discharge undervoltage threshold value and smaller than the lowest work voltage of a system, pressure boosting is carried out on the battery cell, and meanwhile charge-discharge protection can be carried out on a battery.

Description

【Technical field】 [0001] The invention relates to the field of circuit design, in particular to a battery protection circuit with a boost circuit and a single charging and discharging power tube. 【Background technique】 [0002] In the prior art, the lithium battery ensures that the cells in the battery are not under-voltage discharged, over-voltage charged, or over-current discharged through a battery protection circuit (or called a battery protection chip) installed inside it. Please refer to figure 1 As shown, it is a schematic circuit diagram of a lithium battery in the prior art when supplying power. The lithium battery includes a battery cell Bat and a battery protection circuit 110 . The battery protection circuit 110 includes a resistor R1, a capacitor C1, a battery protection control circuit 112, a resistor R4, and NMOS (N-channel Metal Oxide Semiconductor) field effect transistors MN1 and MN2. The positive pole of the battery Bat is directly connected to the firs...

AI Technical Summary

Problems solved by technology

exist figure 1 In the lithium battery shown, if the boost circuit is simply connected in series with the input terminal of the power management chip 120, although the powered circuit 130 can use the energy of the cell voltage between 2.7V and 3.4V, the effect is relatively small. The reason is that the boost circuit itself has a certain efficiency loss. For example, if its efficiency is 90%, it will lose 10% of the energy. In this way, it may not only not prolong the working time of the power supply system, but may reduce the working time instead.

Images