A charging circuit without loss balance charging multiple serial batteries

Abstract

A nondestructive equalizing charge multi-series connceted cell circuit is provided with a battery consisting a plurality of cells which are connected in series. The battery is connected with a power supply unit. A switch is connected between every two cells in series; each cell is connected with a precise voltage detector in parallel so that the voltage detector detects whether the voltage of the cell is full, and transmits the detected result to a charge control circuit which controls the position of the switch. In this way, a charging source of the power supply unit can charge all cells during charging. When the voltage detector detects that voltage of a cell is full, the charge control circuit controls the switch of the cell, and regulates the switch into the off position so that the cell stops charging. In this way, the circuits of the cells full of power are disconnected one by one until completion of charge.

Description

technical field [0001] The invention relates to a charging circuit for non-destructive and balanced charging of multiple batteries connected in series, in particular to a charging circuit for charging multiple batteries connected in series and using a charging control circuit to detect and control each battery. Background technique [0002] With the increasing demand for portable electronic products such as digital cameras, PDA, MP3, ..., etc., the requirements for rechargeable battery capacity are also greater, and the requirements for charging time are also shorter. In addition, the volume of the charger is also increasing. Thinner is required. Therefore, a charger with small size, fast charging, low price and long life seems to be the trend of future development. [0003] However, currently commonly used chargers each have their own advantages and disadvantages, and cannot achieve the aforementioned expected effects, so there is still room for improvement. It is hereby ...

AI Technical Summary

Problems solved by technology

[0004] Please refer to Figure 1, which is a schematic diagram of the charging circuit of a commonly used series charger, which converts the alternating current of AC 100V to 24OV from the mains to DC charging voltage with the power converter 11, and uses the charging circuit 12 pairs in series The connected batteries B1, B2, B3, B4... are charged; the advantage of this charging mode is that the structure is simple and the price is cheap, but its disadvantage is that when one of the batteries is fully charged, if the other is not fully charged, It will cause the fully charged battery to overcharge and cause danger, or stop charging before reaching the maximum charging capacity, or the characteristics of a certain battery will deteriorate after repeated charging / discharging and reduce its service life

[0005] Furthermore, please refer to FIG. 2 , which is a schematic diagram of a charging circuit of a commonly used parallel charger, which is a mode in which the charging circuit 12 charges the batteries B1, B2, B3, B4 ... connected in parallel. The advantage is that the charging voltage of each battery is close, and there is no overcharging disadvantage of the aforementioned series charging; but the biggest disadvantage of this parallel charging mode is that if you want to charge rapidly, you cannot overcome the requirements of rapid charging, and its electronic control parts It is not easy to choose and configure. For example, the charging voltage is 3.7V, and the charging current of each parallel battery is 1.5 amps, so the charging current must be 6 amps, and the transistors of electronic parts have voltage difference problems. There are many problems to be overcome in the current charging circuit. For example, the circuit board line needs to be more than 6mm and the safety specification is not easy to wire, so that the size of the parallel charging type cannot be reduced. Therefore, it has been unable to meet the market requirements

If you want to increase the charging voltage to increase the power and reduce the current, but the four switching transistors Q1, Q2, Q3, and Q4 will have the disadvantage of extremely high temperature due to the voltage difference problem. If the heat sink is too large and the cost will be greatly increased

Images