In the process of external discharge of the protection board, the two electronic switches in the 8205A are not completely equivalent to two mechanical switches, but are equivalent to two resistors with very small resistance, which are called the on-resistance of the 8205A. The on-resistance of each switch is about 30m\U 03a9, and the total is about 60m\U 03a9. The voltage applied to the G pole actually directly controls the on-resistance of each switch when the G pole voltage is greater than 1V When , the on-resistance of the switch is very small (tens of milliohms), which is equivalent to the switch being closed. When the voltage of the G pole is less than 0.7V, the on-resistance of the switch is very large (several MΩ), which is equivalent to the switch disconnect. The voltage UA is the voltage generated by the on-resistance of 8205A and the discharge current. When the load current increases, UA will inevitably increase. Because UA0.006L×IUA is also called the tube voltage drop of 8205A, UA can be simply connected to indicate the size of the discharge current. . When it rises to 0.2V, it is considered that the load current has reached the limit value, so the output voltage of pin 1 is stopped, the voltage of pin 1 becomes 0V, the discharge control tube in 8205A is turned off, and the discharge circuit of the cell is cut off, which will turn off Discharge control tube. In other words, the maximum current that DW01 allows to output is 3.3A, which realizes overcurrent protection.
View the original article on fsqualitypcb.com
