ce9909升压电路.pdfVIP

HIGH EFFICIENCY STEP-UP DC/DC CONVERTER CE9908/09 TINY PACKAGE HIGH EFFICIENCY CE9908/9 STEP-UP DC/DC CONVERTER Introduction Features The CE9908/9 is a CMOS step-up • Low voltage operation: Startup at 0.9 V switching DC/DC converter that mainly min. (IOUT = 1 mA) guaranteed consists of a reference voltage source, an • Duty ratio: 66/78%, builtin auto switching oscillator, and a comparator. The CE9908 • External parts: Coil, capacitor, diode, allows the duty ratio to be automatically NMOS switched according to the load (light load: • High efficiency：±85% （typ. ） 50%, high output current: 75%), enabling • Output voltage Adjustable products with a low ripple over a wide • Providing Flexibility for Using Internal range, high efficiency, and high output and ExternalPower Switches current. With the CE9908/9, a step-up • Zero Shutdown Mode Supply Current switching DC/DC converter can be • 6µA Quiescent (Switch-off) Supply configured by using an external coil, Current capacitor, diode and NMOS or NPN. The • Small SOT23-5,SOT89-5 Package built-in MOSFET is turned off by a SOT-26(customer order ） protection circuit when the voltage at the LX pin exceeds the limit to prevent it from being damaged. This feature, along with the mini package and low current consumption, makes the CE9908 ideal for applications such as the power supply unit of portable equipment. Applications