A7801
AiT Semiconductor Inc.
DC-DC CONVERTER
www.ait-ic.com
LOW NOISE, REGULATED CHARGE PUMP
light load applications the above expression can be used as a guideline in determining a starting capacitor
value.
Power Efficiency
The power efficiency of the A7801 is similar to that of a linear regulator with an effective output voltage of
twice the actual input voltage. This occurs because the input current for a voltage doubling charge pump is
approximately twice the output current. In an ideal regulating voltage doubler the power efficiency would be
given by:
At moderate to high output power the switching losses and quiescent current of the A7801 are negligible and
the expression above is valid. For example with VIN = 3V, IOUT = 50mA and VOUT =5V the measured efficiency
is 80% which is in close agreement with the theoretical 83.3% calculation.
Layout Considerations
Due to its high switching frequency and the high transient currents produced by the A7801, careful board
layout is necessary. A true ground plane and short connections to all capacitors will improve performance and
ensure proper regulation under all conditions.
REV1.0
- JAN 2015 RELEASED -
- 8 -
AITSEMI [ AiT Semiconductor ]
