The typical switch type capacitor sufficient electric pump does not need the inductor, therefore easy to design, and can transforms the positive voltage double and the positive voltage an equivalent negative voltage. But in certain applications, only then positive electricity source available, and the electrical power system must have a scope compared to a positive electricity source voltage amplitude greater negative voltage. Shown in Figure 1 the electric circuit to be possible its input voltage opposition at the same time the obtained negative voltage double.
Usually, MAX889T voltage phase reverser IC1 may transform a input voltage an absolute scope to be lower than its input value negative output voltage. But in this electric circuit, Short base diode D1, D2 and capacitor C4 and C5 may help to produce a higher output voltage. This electric circuit’s specified output is VOUT=-(2×VIN-2VD-IOUT×RO), VIN is the input voltage, VD is the diode forward voltage drop, IOUT is the output current, RO is IC1 under the free movement pattern output impedance. Regarding the 300mA load current, this electric circuit output voltage is -10V. The capacitor and the print circuit wafer walk in the line the parasitic inductance to be possible to produce for the output capacitor charge voltage overswing, thus provides is more than - the 10V output voltage in the non-load situation (Figure 2).
