Uninterrupted power supply (UPS) battery low voltage discharge protection circuit with return difference

Abstract

The invention relates to the field of an uninterrupted power supply (UPS) battery low voltage discharge protection, and in particular relates to a UPS battery low voltage discharge protection circuit with return difference. The UPS battery low voltage discharge protection circuit comprises a starting circuit for starting a control chip U1 of an auxiliary power supply board when an input end voltage achieves a starting threshold VH, and a low voltage blocking circuit for blocking the control chip U1 when the input end voltage is lower than a blocking threshold VL, wherein the starting threshold VH is larger than the blocking threshold VL. As the starting threshold VH and the blocking threshold VL are respectively arranged, and the blocking threshold VL is larger than the starting threshold VH, the situation that the auxiliary power supply board is constantly powered on or powered off when the voltage fluctuates near one threshold is avoided; and meanwhile by adjusting the difference between the starting threshold VH and the blocking threshold VL, the return difference can be set, and the working reliability of the circuit is ensured.

Description

technical field [0001] The invention relates to the field of UPS battery low-voltage discharge protection, in particular to a UPS battery low-voltage discharge protection circuit capable of setting hysteresis. Background technique [0002] In the power frequency UPS (uninterruptible power supply), the connection method of the battery is generally directly connected to the busbar, and the auxiliary power board in the UPS is generally directly connected to the busbar to obtain power, that is, the auxiliary power board is connected to the battery. connect. During the working process of the UPS, when the mains fails to supply power and the battery power supply is started, the voltage of the battery will gradually decrease with the loss of power. power to protect the battery. However, even if the UPS is stopped to supply power to the load, the auxiliary power board inside the UPS will still be in working state and take power from the battery through the busbar, and the operatin...

AI Technical Summary

Problems solved by technology

One way is to add a contactor at the connection end of the battery and the busbar, and disconnect the battery from the busbar when the battery is low voltage, so that the battery is in an open state to protect the battery, but the cost of the contactor is high, and the control circuit needs to be added , It also increases the failure point of UPS power supply and increases the failure rate. The new UPS power supply stops using the contactor, so it cannot effectively protect the battery when the battery is low voltage.

[0003] On the other hand, since the existing protection circuit generally adopts setting a threshold value, and controls whether the auxiliary power board works according to whether the battery voltage is greater than or lower than the threshold value, in this case, when the battery voltage fluctuates near the threshold value, the auxiliary power board will continuously If the ground is powered on and off, it will cause huge damage to the auxiliary power board and the control circuit

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