Abstract: Disclosed is an uninterruptible power supply system, including a sub power supply device configured to supply or cut off sub input power to a load device; a battery configured to supply or cut off battery input power to the load device; and an uninterruptible power supply device that is electrically connected to the sub power supply device and the battery, and when main input power is selectively received and supplied to the load device or the battery input power is selectively received and supplied to the load device, determines whether the main input power and the battery input power are within a predetermined reference main input power range and reference battery input power range, and when the main input power and the battery input power are outside of the reference main input power range and the reference battery input power range, receives the sub input power and supplies the power to the load device.

Abstract: A sigma-delta modulator includes a summing junction that receives an input signal. A plurality of integrators are arranged in series, the integrators output an integrated signal value to a multi-input quantizer. The multi-input quantizer has a plurality of comparators each with switched capacitor inputs. The multi-input quantizer outputs a quantized signal to a multi-bit feedback DAC that drives the summing junction.