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US 7,397,677 B1Granted
Apparatus and method for charge pump control with adjustable series resistance
AssigneeNational Semiconductor Corporation
InventorsMichael John Collins, Richard Frank
Life of this patent
Estimating the term…
Abstract
A charge pump is provided. The charge pump may include an oscillator, a first switch, a second switch, a capacitor/switch network, an error amplifier, an adjustable resistance circuit, a first switch driver, and a second switch driver. In one embodiment, the first and second drivers each receive the oscillator voltage, and drive the first and second switches, respectively. Further, the adjustable resistance circuit is connected in series with the first and second switch circuits. The charge pump is arranged in a closed loop with the error amplifier driving the adjustable resistance circuit. The resistance of the adjustable resistance circuit is modulated to regulate the output voltage.
Claims24
A charge pump circuit, comprising:
- an error amplifier that is operable to provide an error signal that is based, in part, on at least one of an output voltage or a load current;
- an adjustable resistance circuit that is operable such that a resistance across the adjustable resistance circuit is approximately proportional to the error signal, wherein the adjustable resistance circuit is arranged such that the error amplifier drives the adjustable resistance circuit;
- and
- a plurality of switch circuits that is operable to enable:
- during a sample phase, coupling a flying capacitor in series with the adjustable resistance circuit,
- wherein the plurality of switch circuits includes:
- a first switch circuit that is coupled to a first flying capacitor node;
- a second switch circuit;
- a third switch circuit that is coupled to a second flying capacitor node, wherein the charge pump circuit is arranged to operate with the flying capacitor coupled between the first flying capacitor node and the second flying capacitor node;
- a fourth switch circuit that is coupled between the second flying capacitor node and a third flying capacitor node;
- a fifth switch circuit that is coupled to the third flying capacitor node;
- a sixth switch circuit that is coupled to a fourth flying capacitor node, wherein the charge pump circuit controller is arranged to operate with a second flying capacitor between the third flying capacitor node and the fourth flying capacitor node;
- and
- a seventh switch circuit that is coupled between the fourth flying capacitor node and an output node.
11 more elements
A charge pump circuit, comprising:
- an error amplifier that is operable to provide an error signal that is based, in part, on at least one of an output voltage or a load current;
- an adjustable resistance circuit that is operable such that a resistance across the adjustable resistance circuit is approximately proportional to the error signal, wherein the adjustable resistance circuit is arranged such that the error amplifier drives the adjustable resistance circuit;
- and
- a plurality of switch circuits that is operable to enable:
- during a sample phase, coupling a flying capacitor in series with the adjustable resistance circuit, wherein
- the plurality of switch circuits includes:
- a first switch circuit that is coupled to a first flying capacitor node;
- a second switch circuit;
- a third switch circuit that is coupled to a second flying capacitor node, wherein the charge pump circuit is arranged to operate with the flying capacitor coupled between the first flying capacitor node and the second flying capacitor node;
- and
- a fourth switch circuit that is coupled to the second flying capacitor node, wherein the third switch circuit is coupled between the second flying capacitor node and a ground node.
8 more elements
A method for regulation, comprising:
- providing an error signal that is based, in part, on a difference between a feedback signal and a reference signal, wherein the feedback signal is based, at least in part, on at least one of an output voltage or a load current;
- employing the error signal to drive an adjustable resistance circuit such that a resistance of the adjustable resistance circuit is modulated based on the error signal;
- during a sample phase, coupling a flying capacitor in series with the adjustable resistance circuit;
- during a hold phase, transferring charge between the flying capacitor and an output capacitor;
- and
- during the hold phase, transferring charge between a second flying capacitor and the output capacitor, wherein coupling the flying capacitor in series with the adjustable resistance circuit includes coupling the adjustable resistance circuit in series with a parallel combination of the flying capacitor and the second flying capacitor.
3 more elements
A charge pump circuit, comprising:
- an error amplifier having at least an output that is coupled to a first node;
- an adjustable resistance circuit that is coupled between a second node and a low power supply node, wherein the adjustable resistance circuit is further coupled to the first node;
- a first switch circuit that is coupled between a high power supply node and a first flying capacitor node;
- a second switch circuit that is coupled between the first flying capacitor node and the second node;
- a third switch circuit that is coupled to a second flying capacitor node;
- a fourth switch circuit that is coupled between the second flying capacitor node and a third flying capacitor node;
- a fifth switch circuit that is coupled to the third flying capacitor node;
- a sixth switch circuit that is coupled to a fourth flying capacitor node;
- and
- a seventh switch circuit that is coupled between the fourth flying capacitor node and an output node.
7 more elements
A charge pump circuit, comprising:
- an error amplifier having at least an output that is coupled to a first node;
- an adjustable resistance circuit that is coupled between a second node and a low power supply node, wherein the adjustable resistance circuit is further coupled to the first node;
- a first flying capacitor that is coupled between a first flying capacitor node and a second flying capacitor node;
- a first switch circuit that is coupled between a high power supply node and the first flying capacitor node;
- a second switch circuit that is coupled between the first flying capacitor node and the second node;
- a first diode that is coupled to the second flying capacitor node;
- and
- a second diode that is coupled to the output node.
5 more elements
A charge pump circuit, comprising:
- an error amplifier having at least an output that is coupled to a first node;
- an adjustable resistance circuit that is coupled between a second node and a low power supply node, wherein the adjustable resistance circuit is further coupled to the first node;
- a first switch circuit that is coupled between a high power supply node and a first flying capacitor node;
- a second switch circuit that is coupled between the first flying capacitor node and the second node;
- a third switch circuit that is coupled between the low power supply node and a second flying capacitor node;
- and
- a fourth switch circuit that is coupled between the second flying capacitor node and the output node.
4 more elements
A method for regulation, comprising:
- providing an error signal that is based, in part, on a difference between a feedback signal and a reference signal, wherein the feedback signal is based, at least in part, on at least one of an output voltage or a load current;
- employing the error signal to drive an adjustable resistance circuit such that a resistance of the adjustable resistance circuit is modulated based on the error signal;
- during a sample phase, coupling a flying capacitor in series with the adjustable resistance circuit;
- and
- during a hold phase, transferring charge between the flying capacitor and an output capacitor, wherein transferring charge between the flying capacitor and the output capacitor includes coupling the flying capacitor between ground and the output capacitor during the hold stage.
2 more elements
Dependencies are inferred from the claim text.