why charge pumps?

[docb]

Is a charge pump circuit just more efficient than using a transformer earlier to get the higher voltage? Or is it mainly when it's all DC, so transformers are not an option?

 

[Laplace]

The virtues of charge pumps are simplicity and efficiency. However, inductorless DC-DC power conversion is generally reserved for low-power applications where the voltage change from source to load is limited. Higher currents and greater voltage change generally requires use of inductors or even oscillator-driven transformers for DC-DC power.

 

[docb]

Thanks, helpful.