Switching regulator current sensing circuits and methods
AssigneeQUALCOMM Incorporated
InventorsJoseph Rutkowski, Yikai Wang, Jiwei Chen
Life of this patent
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Abstract
In one embodiment, a switching regulator includes an inductor, a first switch, and a second switch. The first and second switches generate current in the inductor. Inductor current may flow through the second switch with both a positive and negative polarity. Voltages on terminals of the second switch may be sensed, and an offset applied to generate a level shifted signal. In one embodiment, the switching regulator is a boost switching regulator, and the offset is generated using a current source. Matched MOS transistor switches may be used to couple voltages on terminals of the second switch to amplifier inputs, and the offset is introduced across an MOS switch coupled between one amplifier input and the output.
Claims19
A boost switching regulator circuit comprising:
- an inductor having a first terminal configured to receive a first voltage and a second terminal;
- a first switch having a first terminal coupled to the second terminal of the inductor and a second terminal coupled to a reference voltage;
- a second switch having a first terminal coupled to the second terminal of the inductor and a second terminal coupled to a second voltage greater than the first voltage;
- and
- a control circuit coupled to the second terminal of the second switch and configured to control the first switch and the second switch based on the second voltage and a current, the control circuit comprising a current sense circuit coupled to the first terminal of the second switch and the second terminal of the second switch,
- wherein a current through the second switch transitions from a positive polarity to a negative polarity over a cycle, and wherein the current sense circuit is configured to generate a level shifted signal representing the current through the second switch, and wherein a polarity of the level shifted signal is positive over the cycle of the current through the second switch.
A switching regulator circuit comprising:
- an inductor;
- a first switch having a first terminal and a second terminal;
- a second switch having a first terminal and a second terminal, wherein the first terminal of the first switch and the first terminal of the second switch form a switching node, and wherein the inductor is coupled to the switching node;
- and
- a control circuit coupled to the second terminal of the second switch and configured to control the first switch and the second switch based on an output voltage and an inductor current, the control circuit comprising a current sense circuit coupled to the first terminal of the second switch and the second terminal of the second switch,
- wherein the inductor current flows through the second switch and transitions from a positive polarity to a negative polarity over a cycle, and wherein the current sense circuit is configured to generate a level shifted signal representing the inductor current through the second switch, and wherein a polarity of the level shifted signal is positive over the cycle of the inductor current through the second switch.
A method of generating a regulated voltage comprising:
- controlling a first switch and a second switch to open and close during a cycle to generate a current in an inductor, the inductor receiving a first voltage on a first terminal, wherein the first switch has a first terminal coupled to a second terminal of the inductor and a second terminal coupled to a reference voltage, and wherein the second switch has a first terminal coupled to the second terminal of the inductor and a second terminal having an second voltage greater than the first voltage, and wherein the first switch and the second switch are opened and closed based on the second voltage and the current;
- and
- sensing the current through the second switch when the second switch is closed, wherein the current through the second switch transitions from a positive polarity to a negative polarity over the cycle;
- and
- generating, based on the sensing the current, a level shifted signal representing the current through the second switch, and wherein a polarity of the level shifted signal is positive over the cycle of the current through the second switch, wherein sensing the current comprises generating an offset so that a sensed voltage corresponding to a voltage across the second switch remains positive when the voltage across the second switch transitions from positive to negative.
Dependencies are inferred from the claim text.