Patent ID: 7382062

Claim:
A wide voltage range stabilized switching power supply for valve actuators of the type comprising: a common mode input filter ( 2 ) for removing common mode noise; a diode bridge ( 3 ) rectifier producing a rectified voltage; a boost stage ( 4 ) generating a boost stage voltage, the boost stage being located upstream from a power stage ( 7 ) and voltage equalizing capacitors ( 5 ) connected in parallel, for equalizing the rectified voltage; and an auxiliary power supply stage ( 6 ) formed by a switch mode circuit with an operating range of 21 to 380 VDC, which generates supply voltages required for internal operation of the power supply; and a power stage ( 7 ) that receives the boost stage voltage varying in the range of 120 VDC to 373 VDC and generates the output voltages required for supplying a load; characterized in that the boost stage ( 4 ) also acts as a Power Factor Corrector (PFC), to reduce reactive power and has an efficiency of more than 90%; and characterized in that said boost stage ( 4 ) can operate in two modes: a low range mode, operating in the input voltage range of 21.6 VDC to 120 VDC (90 VAC); a high range mode, operating in the range of input voltages above 120 VDC (90 VAC); in the low range mode, the boost stage 4 increases the input voltage, varying in the range of 21.6 VDC to 120 VDC (90 VAC), to the constant value of 120 VDC, which in turn provides the supply to the full bridge circuit of the power stage ( 7 ); and in the high range mode, the boost stage ( 4 ) is automatically shunted by an overvoltage measuring circuit, in which case the power stage ( 7 ) operates at the rectified voltage (from 120 VDC (90 VAC) to 372 VDC (264 VAC)).