PWM CONTROLLED， PWM/PFM SWITCHABLE STEP-UP DC-DC CONTROLLER
DESCRIPTION
The UTC UC3550 series is a compact, high efficiency, step-up
DC/DC controllers includes an error amplifier, oscillator, PWM
comparator, skip cycle comparator, voltage reference, soft-start, and
high speed lower ON-resistance driver for driving external power
devices (NMOS or NPN) ,Additionally, a CE (chip enable) function that
reduces power consumption during shut-down mode.
That typically operated from a single-or dual-cell battery packs. It
have a driver pin ,ext pin, for connecting to an external transistor(NMOS
or NPN). a lower ON-resistance external transistor can obtain larger
output current. With only external components, this series allow a
simple means to accommodate high output current applications.
The UTC UC3550 series goes automatically into skip switching
cycles under light load condition to maintain high efficiency.
FEATURES
* Input Voltage Range：0.9~8V
* Output Voltage Range：1.8~6V Programmable in 0.1V with High
Accuracy ± 2.5%
* High Efficiency 88% (Typ.)
* Low Start-up Voltage of 0.9V Typical at IOUT = 1.0mA
* Oscillator Frequency: 300kHz.(±20%)
* Chip Enable Pin with Pull-up Current Source
* High Output Current up to 1000mA (VIN = 2.0V, VOUT =3.3V) |
