Multiple output switched capacitor DC-DC converter for low power applications

Switched capacitor (SC) DC-DC voltage converters have been widely used for low-power applications. These converters play a role of voltage doublers or are used to obtain a dc voltage with reverse polarity. They may also be configured to implement a particular voltage conversion ratio. However, there are applications which require multiple output voltages. If multiple output voltages are required, such converters are duplicated and tuned to obtain the desired output voltages. Employing a separate switched capacitor DC-DC converter for each output increases the silicon area and results in higher cost. Thus, a simple, low-complexity SC DC-DC conversion scheme is proposed, which obtains multiple output voltages from a single input source. The scheme is scalable in nature and is well suited for integration. The scheme is demonstrated using a test chip fabricated in 0.18μm CMOS process.