Patent ID: 8270140

Claim:
A system for controlling a set of bi-stable solenoids for electromagnetic locking systems comprising: a power supply; a capacitor charge circuit connected to the power supply; a polarity control circuit connected to the capacitor charge circuit; and a solenoid select circuit comprised of a set of solenoids and connected to the polarity control circuit, the capacitor charge circuit comprising i) a capacitor for providing a decreasing voltage in accordance with a voltage dropping curve to the set of solenoids, said capacitor located in parallel to the power supply, ii) a switch connecting a positive lead of the capacitor to either the power supply or to the polarity control circuit by a first power lead, and iii) a second power lead connects a negative lead of the capacitor to the power source and is directly connected to said polarity control circuit, the polarity control circuit comprising a first and a second switch, each switch having a first and a second pole connected to the positive and the negative power lead of the capacitor charge circuit respectively by means of a first and a second power lead, and each switch having a center pole connected to the solenoid selector circuit by means of a third and a fourth power lead, and each solenoid of the solenoid selector circuit having a first and a second pole, wherein the first pole of each solenoid is connected to a respective switch, said solenoid selector circuit receiving a first and a second power lead from the polarity control circuit, and wherein i) the second power lead is connected to the second pole of all the solenoids and ii) the first power lead is connected to each solenoid switch in the circuit as a common to all the switches.