Datasheet

Basic Operation of the Device
1-2
1.1 Basic Operation of the Device
Except for the REG710–5, the REG710 series of charge pumps work in a
buck/boost fashion. They will produce a regulated output over the entire input
range.
The charge pump consists of switches, oscillator, bandgap, comparator, and
mode control circuits. The comparator senses a divided down version of
output voltage and compares that to the bandgap voltage. If the sensed output
voltage is less than the bandgap voltage, the part begins pumping. When the
sensed output voltage is greater than the bandgap voltage, the pumping stops.
This pulse frequency modulation is how the charge pump regulates the output.
The mode control circuit determines if the part needs to operate in boost or
buck mode.
In boost mode the pump capacitor is charged up from the input and then
connected between the input and output. In buck mode, the pump capacitor
is connected to the input and ground. The output capacitor receives current
pulses from the switches.