The HN9261 series are PFM Step-up DC/DC ICs (pulse voltage regulators) with output voltages 1.5; 2.5; 3.3; 5.0V. The ICs of pulse voltage regulators are purposed for use in power supply sources of consumer & industrial electronic devices with battery-power sourcing. The application of this ICs permit to keep constant output voltage of power supply source even in the case of low charge level of the battery.
The HN9261 consists of an oscillator, a PFM control circuit, a driver transistor (LX switch), a reference voltage unit, an error amplifier, resistors for voltage detection, and a LX switch protection circuit. A low ripple and high efficiency step-up DC/DC converter can be constructed of this HN9261 with only three external components.
The HN9261A provides with a drive pin (EXT) for an external transistor, so that a power transistor can be externally applied. Therefore, the HN9261A IC is recommended for applications where large currents are required. EN pin enables circuit to set the standby supply current at a maximum of 0.5μA.