zxcp330 Zetex Semiconductors plc., zxcp330 Datasheet - Page 7

• Manufacturer Part Number: zxcp330
• Description: Switched Capacitor Dc-dc Converter
• Manufacturer: Zetex Semiconductors plc.

TYPICAL APPLICATIONS
Low quiescent current, regulated operation
By pulsing the enable pin (pin 3) lower quiescent
operating current can be achieved while maintaining
output voltage regulation. A pulse frequency of 100Hz
with a 2% duty cycle is a suitable to achieve a 10 A
operating current.
LED driver
Below is a typical LED driving application for a cell
phone. The ZXCP330 drives a coloured LED with a
typical forward voltage of 2.5V from a single Li-on
battery input. The LEDs can be driven in parallel to
provide backlighting for LCD displays and keypad
illumination. The LED current is regulated by R1 and is
configured for 20mA.
PROVISIONAL ISSUE A - DECEMBER 2001
7
Low noise 3V supply
By adding the ZXCL300 3V regulator to the output of
the ZXCP330, the output voltage ripple can be
eliminated.
A typical waveform of the reduction in noise is shown
below.
Channel 1: V
Channel 2: V
V
IN
=4.4V; I
OUT
OUT
OUT
=40mA; Time base=2 s/DIV
ZXCP330 @20mV/DIV
ZXCL300 @20mV/DIV
ZXCP330