Typically, a charge pump consists of a series of switches, diodes, and capacitors.
The basic operation involves charging and discharging the capacitors in a specific sequence to create the desired output voltage. Here's a brief explanation of the process:
Pumping Phase: During this phase, the input voltage is applied to one side of the capacitor, while the other side is grounded. The switches control the connection between the input and the capacitor, allowing it to charge up to the input voltage.
Voltage Conversion Phase: In this phase, the charged capacitor is connected to the output side, while the input side is disconnected. The voltage on the capacitor is then doubled by utilizing voltage doubler circuits, which involve diodes and additional capacitors.
Output Phase: The doubled voltage on the capacitor is transferred to the output, providing the desired higher DC voltage.
The output is regulated and filtered to minimize any voltage ripples or fluctuations.
Charge pumps are commonly used in various applications where voltage conversion is required, such as voltage multipliers, LCD biasing, flash memory programming, and voltage regulators. They offer advantages like simplicity, low cost, and efficiency. However, they may have limitations in terms of output current capability and voltage ripple, depending on the specific design and components used.