Reduced capacitor charge-pump
AssigneeDialog Semiconductor GmbH
InventorsHynek Saman, Jim Brown
Life of this patent
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Abstract
Systems and methods to achieve a charge pump for generating from single supply voltage energy efficient supply voltages that are symmetrical around ground voltage have been disclosed. The charge pump requires two flying capacitors only. The charge pump generates positive and negative supply voltages following a 1/N ratio of Vdd voltage, i.e. +−Vdd/N, and can be generalized to generate +/−Vdd/2N voltages. This is especially useful for supplying class-G amplifiers.
Claims28
A method for generating from a single supply voltage Vdd energy efficient supply voltages being symmetrical around ground voltage, comprising the following steps:
- (1) providing an input voltage Vdd and a charge pump circuit, having a positive and a negative output node, comprising a digital controller, a set of switches, two or more flying capacitors leading to output voltage ratios of +/−Vdd/2N with just N flying capacitors, and two reservoir capacitors;
- (2) setting output voltage modes desired on the digital controller;
- (3) setting switches in order to put voltages on the flying capacitors and on at least one output port according to one or more equations describing a first phase of an actual output voltage mode of the charge pump;
- (4) setting switches in order to put voltages on the flying capacitors and on at least one output port according to one or more equations describing a second phase of an actual output voltage mode of the charge pump;
- (5) setting switches in order to put voltages on the flying capacitors and on one or more output port according to one or more equations describing a third phase of an actual output voltage mode of the charge pump;
- (6) setting switches in order to put voltages on the flying capacitors and on one or more output port according to one or more equations describing a fourth phase of an actual output voltage mode of the charge pump;
- (7) go to step (8) if charge pump is on, else go to step (10);
- (8) go to step (9) if output voltage mode is to be changed, else go to step (3);
- (9) change output voltage mode and go to step (3);
- and
- (10) end.
A charge pump generating from a single supply voltage Vdd energy efficient supply voltages being symmetrical around ground voltage, comprises:
- a digital controller, controlling the operation of the charge pump in a way that the charge pump is providing just the amount of power required by a stage supplied by the charge pump;
- a first input port connected to Vdd voltage;
- a second input port connected to ground;
- a positive output node;
- a negative output node;
- two reservoir capacitors, wherein a first reservoir capacitor is connected between the positive output node of the charge pump and ground and a second reservoir capacitor is connected between the negative output node of the charge pump and ground;
- two or more flying capacitors leading to output voltage ratios of +/−Vdd/2N with just N flying capacitors;
- and
- a set of switches activating charging of the flying capacitors and connecting first or second plates of the flying capacitors to the positive and negative output nodes wherein the set of switches and the related charging of the flying capacitors are controlled by the digital controller in way that the positive and negative output nodes supply symmetrical output voltages required.
Dependencies are inferred from the claim text.