The ZXSC410/420/440 are DC-DC boost controllers. Their wide input voltage range make suitable for operation from a number of battery configurations including single Li-Ion cell and 2~3 alkaline/NiCd/NiMH cells. Using high gain Diodes Zetex-brand switching npn-transistors allow high voltage boost ratios and/or high output current depending on transistor. The ZXSC410/440 has a shutdown feature that can also be used for some dimming functionality. ZXSC420/440 includes an End of Regulation flag that can be used to indicate when the regulator is no longer able to maintain the regulated output voltage/current or has reached the required current/voltage. The ZXSC440 combines the features of the ZXSC410 and ZXSC420 into one device.