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How are charges stored in a charge pump circuit?
Another method for developing supply voltage for op amp systems employs what is known as a charge-pump circuit (also called switched capacitor voltage conversion). Charge-pump voltage converters accomplish energy transfer and voltage conversion using charges stored on capacitors, thus the name, charge-pump.
How are supply charge pumps used in 5V transceivers?
Parallel operation of the supply charge pumps for 5V powered transceivers is easily achieved to minimize component count. The positive and negative supply have approximately 1μF of holding capacitance for energy storage.
Can a charge pump be used in a voltage doubler?
Charge-pumped circuits similar to the voltage doubler can be built to provide higher voltages, usually integer-multiples of the input voltage (that is, 2×, 3×, etc.). There are also many integrated circuit solutions available for implementing this circuit.
When is a charge pump capacitor charged to the voltage?
The two common charge-pump voltage converters are the voltage inverter and the voltage doubler circuits. In a voltage inverter, a charge pump capacitor is charged to the input voltage during the first half of the switching cycle.
When does the charge pump not need to be on?
The charge-pump does not have to deliver any current to the loop filter when in lock, but still the up and down switch will be on for a small amount of time. The implementation shown in Figure 7.12 uses a switched current source, which only needs a fixed bias voltage but no static DC current.
How much power does a 5V charge pump generate?
The power supply generator on 5V powered devices is a charge pump circuit which generates approximately ±9V from a single 5V supply. Parallel operation of the supply charge pumps for 5V powered transceivers is easily achieved to minimize component count.