The overpowering protective circuit diagram with the direct current and current measuring system MAX4211

Published:2011/3/22 21:14:00 Author:Ecco | Keyword: The overpowering protective circuit, direct current, current measuring system | From:SeekIC

The overpowering protective circuit with MAX4211 is as below. The working principle is that the protective circuit will cut off the load current when checking out the overpowering error. The circuit can avoid the batteries from the damage of overpower of short circuit. Once it check out the overpowering error, the circuit will cut off P channel MOSFET(V) until pressing the reseting button. Simultaneously, the input power will make LE pin be in low level, and the output 1 of comparator 1 won't be locked, and the protective circuit will reset. When the characteristic of load changing, the load may produce surging current and higher voltage on POUT to cause malfunction. To avoid the circumstance, the circuit could connect a RC network(R4 and C1), and it can provide high level to INHIBIT port of comparator 1. In the term, the comparator 1 wil stop working, and the time of pause is decided by the formula that showing as below: t=R4C1ln(△U/0.6)。 In the formula, △U is variance of load voltage. The RC net will not produce an effect on the protection of long time overpowering circuit. R3 is resistance of the current limiter in 10kΩ. Follow the above-mentioned circuitry, it can be used as measuring the error of current, the exact method is connecting the resistance divider R1～R2 to IOUT port.



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