Digital loop for regulating DC/DC converter using segmented switching

Abstract

A power control circuit is provided containing a switch array, which includes segmented switches, a flying capacitor, an output voltage terminal, a feedback loop, and a digital voltage regulator block. The digital voltage regulator block includes an A / D converter, an encoder, an add-subtractor, and a gate logic. These power control circuits do not include pass transistors. A method is also provided, where the charge pumps of the power control circuit are operated in two-phase cycles including a charging phase and a pumping phase. The power control circuit is controlled in both of these phases, thereby reducing the ripple of the output voltage.

Description

technical field [0001] This invention relates generally to power supplies and, more particularly, to switched capacitor charge pump power supplies for generating a regulated output voltage different from the supply voltage. Background technique [0002] An unregulated switched capacitor DC / DC converter consists of an array of switches. Figure 1A An existing converter topology is shown. The converter uses a flying capacitor and four switches. Figure 1B Another existing topology is shown with two flying capacitors and nine switches. [0003] figure 2 A three-terminal device equivalent to this switch array is shown. Step-up, step-down and inverting topologies can be created by connecting the TOP, MID and BOT terminals in various combinations with input, output and ground. [0004] image 3 A 2:1 buck charge pump is shown. The switches are driven using a two-phase non-overlapping clock. In phase 1, the charging phase, switches S1 and S3 are switched on. Therefore, the...

AI Technical Summary

Problems solved by technology

Pass transistor 47 is typically large and takes up valuable die area

Also, during the pumping phase, charge is transferred from the flying capacitor C1 to the output capacitor C out The flow rate of the uncontrolled

Therefore, the output voltage ripple is uncontrolled and can be quite large

Also, loop stability limits the choice of external output capacitor and its equivalent series resistance

The transient performance of the charge pump is limited by the control loop bandwidth and is not satisfactory

Finally, the dynamic losses associated with the on / off of an array of tuned switches can be high

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